State of surface water quality in Tasman District, RG Young, TI James, J Hay, R Smith

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Content: STATE OF SURFACE WATER QUALITY IN TASMAN DISTRICT
Document Status: Final Report
June 2005 A technical report presenting results of the Tasman District Council's "State of the Environment" Surface Water Quality Monitoring Programme from 1999 to April 2004 incorporating monitoring data collected by National Water Quality Network from 1989 to 2003 and other data. Along with physical and chemical indicators, results from macroinvertebrate and periphyton indicators are presented. The report highlights freshwater quality issues and outlines what Tasman District Council is doing to help improve water quality where it is found to be poor.
Prepared By: Roger Young1 Trevor James2 Joe Hay1
Reviewed by: Rob Smith2
Cover Photos: From Top: Matakitaki River at Nardoo, Motupipi River at Factory Farm Crossing, Kaituna River at Sollys.
Tasman District Council Ref: R05007 Cawthron Report No. 933 ISBN: 0-473-10060-6 File ref: G:\Environmental\Trevor James\Surface Water Quality\Reports\SER 2005\SWQ SER June2005 - Final Draft1.doc
1Cawthron Institute 98 Halifax Street East Private Bag 2 NELSON
2Tasman District Council 189 Queen Street Private Bag 4 RICHMOND
EXECUTIVE SUMMARY
As part of its obligations under the Resource Management Act, Tasman District Council monitors the state of surface water quality and river health at selected sites throughout the Tasman District. Data from this monitoring programme and selected information collected as part of scientific studies carried out by other agencies in the District are reviewed in this report.
A range of water quality parameters have been measured at most sites on a quarterly basis at base flow since 1999. Samples of aquatic macroinvertebrates have been collected annually since 1999 at most of the water quality sampling sites. Some types of macroinvertebrates are tolerant to pollution while others are not. Therefore, the presence or absence of particular macroinvertebrate species can indicate the ecological health of a site. The amount and types of periphyton (or algae) growing on the river bed is also indicative of river health and has been measured quarterly at most of the water quality sampling sites since 2001.
A cluster analysis of the water quality results identified three groups of sites. One group consisting of eight small streams had poor water quality. These sites (subsequently labelled as the "red" sites) have poor water clarity and high concentrations of nutrients and faecal indicator bacteria compared with other sites in the District and often exceed water quality guidelines. Dissolved oxygen concentrations were low at times at some of these sites. All of these sites are on small streams draining land that has been intensively developed for agriculture, horticulture, or urban usage. Sites in this group include: Motupipi, Watercress and Winter Creeks (near Takaka), Little Sydney and Waiwhero Creeks (near Motueka), Kikiwa (upper Motueka) and Reservoir Creek in Richmond.
A second group of 11 sites (subsequently labelled as the "yellow" sites) have better water quality than the red sites, but tend to have lower water clarity and higher concentrations of nutrients and faecal bacteria than that in the high quality ("green") sites. The yellow sites include small streams and the downstream end of moderate sized rivers that drain intensively developed areas. Sites in this group include: lower Riwaka, lower Sherry (near Tapawera), Mangles (near Murchison), lower Onekaka (Golden Bay), lower Wai-iti (near Brightwater), Motupiko (upper Motueka catchment), Black Valley (in St Arnaud), and Kaituna (near Collingwood).
The remaining "green" sites had the highest water quality and included forested headwaters and also the downstream reaches of the District's large rivers. Sites in this group include: Motueka, Takaka, Aorere, Buller, Matakitaki, Waimea, Wairoa, Wangapeka.
Sites draining low elevation land had higher concentrations of TN, NO3-N, NH4-N, DRP, TP, E. coli, and suspended sediments than sites draining hill country, mountains or flowing from a lake. Oxygen saturation was lowest in first order streams. Concentrations of nutrients also tended to be highest in the smaller streams. Concentrations of nutrients, E. coli and suspended sediment at sites classified as having pastoral land cover were higher than at sites with indigenous forest or exotic forest land cover. Similarly, water clarity was lower at pastoral sites than in forested sites. The effects of land use on water quality are widely recognised and the results of this analysis are consistent with earlier nationwide studies of water quality patterns.
Continuous water temperature records were available for 23 sites, mostly within the Motueka River catchment. Data from well-shaded headwater streams never exceeded the temperature criteria for protecting ecosystem health during the summer. However, the water temperature criterion was regularly exceeded during summer at sites on small unshaded streams draining developed land (e.g. Waiwhero, Little Sydney, Kikiwa). The temperature criterion was also regularly exceeded in the lower reaches of the Tadmor and Motueka rivers.
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Trends in water quality were determined at the three National River Water Quality Network sites (Motueka at Gorge, Motueka at Woodstock, Buller at Longford) where sampling has been conducted monthly since 1989. Concentrations of ammonium nitrogen declined at all three sites over the course of the data record, whereas concentrations of total nitrogen increased at all three sites. Water clarity also tended to increase at all three sites, including the Gorge site, which is upstream of any human land use, over the course of the data record. The fact that these changes were consistent among all three sites suggests that this trend is related to Climatic Changes, rather than changes in land management. However, nitrate nitrogen concentrations and conductivity increased significantly at the Motueka at Woodstock site over the course of the data record, but not at the other sites, suggesting that these changes may be related to changes in land use within the Motueka Catchment over the last 16 years. Macroinvertebrate communities indicated good ecosystem health at the majority of the sites that were sampled. However, ecosystem health appears to be poor in many of the small lowland streams that drain the intensively developed parts of the District (e.g. Motupipi River, Watercress Creek, lower Reservoir Creek, Waiwhero, Little Sydney). These sites were also identified as having poor water quality. Periphyton communities were also indicative of good ecosystem health at the majority of sites. However, again the small lowland streams draining intensively developed land often had excessive accumulations of nuisance algae. In terms of water quality, the Tasman District is lucky because all of the District's large rivers have a significant proportion of native forest in their catchments. Therefore, any inputs of pollutants from developed land in the middle and lower reaches are substantially diluted by the large volume of high quality water from upstream. The main threats to water quality and stream health in the Tasman District relate to the intensification of agriculture in the District, and to a lesser extent the expansion of residential development in the District. The main problems with water quality in the Tasman District are currently found in small streams which drain intensively developed land. Restoration efforts should focus on reducing nutrient and faecal bacteria inputs to these systems. Efforts should also be made to increase the amount of bank-side vegetation along these streams to provide shading and keep water temperatures below the critical levels required for protecting ecosystem health. If improvements can be made to the water quality of many small streams, this will also lead to cumulative improvements in the quality of water in the main rivers.
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TABLE OF CONTENTS
1 INTRODUCTION ............................................................................................................................................... 1 1.1 The Pressure State Response Model ............................................................................................................ 1 1.2 Programme Design....................................................................................................................................... 2
2 SAMPLING SITES ............................................................................................................................................... 3 2.1 Water Quality ............................................................................................................................................... 3 2.2 Macroinvertebrates....................................................................................................................................... 6 2.3 Periphyton ............................................................................................................................................... 8
3 WATER QUALITY .............................................................................................................................................. 8 3.1 Patterns Across Sites and Exceedance of Guidelines ................................................................................... 8 3.1.1 Dissolved Oxygen............................................................................................................................. 9 3.1.2 pH ............................................................................................................................................. 12 3.1.3 Nitrogen .......................................................................................................................................... 13 3.1.4 Phosphorus...................................................................................................................................... 16 3.1.5 Clarity and Turbidity....................................................................................................................... 19 3.1.6 Faecal Indicator Bacteria ................................................................................................................ 20 3.2 Site Groupings............................................................................................................................................ 23 3.3 Water Quality in Relation to the River Environment Classification Groupings ........................................ 24 3.3.1 The REC System............................................................................................................................. 25 3.3.2 Interpreting Water Quality Data With Respect to REC Groupings ................................................ 26 3.4 Water Temperature..................................................................................................................................... 31 3.5 Trends at National River Water Quality Network Sites ............................................................................. 34
4 MACROINVERTEBRATES ............................................................................................................................. 37 4.1 Site Groupings............................................................................................................................................ 42 4.2 REC Groupings .......................................................................................................................................... 43 4.3 Trends in Macroinvertebrate Data.............................................................................................................. 46
5 PERIPHYTON ............................................................................................................................................. 46
6 DISCUSSION OF THE STATE OF TASMAN'S SURFACE WATER QUALITY ..................................... 49
6.1 General
............................................................................................................................................. 49
6.2 Pressure, State and Response in Relation to Various Resource Use Activities.......................................... 50
6.2.1 Sewage Discharges from Municipal Sewerage Systems................................................................. 50
6.2.2 Discharges from Farms and Fertiliser Operations........................................................................... 52
6.2.3 Stream Habitat Modification........................................................................................................... 54
6.2.4 Water Takes .................................................................................................................................... 54
6.2.5 Discharges of Sediment from Earthworks and Stockpiling of Material.......................................... 55
6.2.6 Forestry ........................................................................................................................................... 56
6.2.7 Industries Storing of Using Hazardous Chemicals ......................................................................... 58
6.2.8 Orcharding ...................................................................................................................................... 60
6.2.9 Winery Waste Disposal................................................................................................................... 61
6.2.10 Other Fruit Growing ....................................................................................................................... 62
6.2.11 Market Gardening ........................................................................................................................... 62
6.2.12 Fish Farms....................................................................................................................................... 62
6.2.13 Miscellaneous Discharges............................................................................................................... 62
6.3 General Response....................................................................................................................................... 63
7 RECOMMENDATIONS .................................................................................................................................... 64
8 REFERENCES ............................................................................................................................................. 67
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Table 1 Table 2 Table 3 Table 4
LIST OF TABLES Guideline Water Quality Values for Protection of River Ecosystem and Human Health ............................ 9 Summary of Factors and Categories Used in the REC Classification........................................................ 25 Significant (p <5%) Trends in Water Quality Parameters at the NRWQN Sites ....................................... 36 Criteria for water quality based on macro-invertebrate indices...................................................37
LIST OF FIGURES
Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13a Figure 13b Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 30a Figure 31
The Pressure-State Response Model of Environmental Change .................................................................. 1 Water Quality Monitoring Sites Throughout the Tasman District ............................................................... 5 Macroinvertebrate Monitoring Sites Throughout the Tasman District ........................................................ 7 Proportion of Dissolved Oxygen (% Saturation) Measurements at Each Site That Met or Exceeded Guidelines ............................................................................................................................................. 10 Proportion of Dissolved Oxygen (mg/L) Measurements at Each Site That Met or Exceeded Guidelines . 11 Proportion of pH Measurements at Each Site That Met or Exceeded Guidelines...................................... 12 Proportion of Total Nitrogen Measurements at Each Site That Met or Exceeded Guidelines ................... 14 Proportion of Dissolved Inorganic Nitrogen Measurements at Each Site That Met or Exceeded Guidelines ............................................................................................................................................. 15 Proportion of Total Phosphorus Measurements at Each Site That Met or Exceeded Guidelines............... 17 Proportion of Dissolved Reactive Phosphorus at Each Site That Met or Exceeded Guidelines................. 18 Proportion of Water Clarity Measurements at Each Site That Met or Exceeded Guidelines ..................... 19 Proportion of Turbidity Measurements at Each Site That Met or Exceeded Guidelines............................ 20 Proportion of Faecal Indicator Bacteria Measurements at Each Site That Met or Exceeded Guidelines for Contact Recreation ............................................................................................................................... 21 Proportion of Faecal Indicator Bacteria Measurements at Each Site That Met or Exceeded Guidelines for Stock Drinking...................................................................................................................................... 22 Clustering of the Sites Based on Their Water Quality ............................................................................... 23 Ordination of Sites Based on Their Water Quality..................................................................................... 24 Comparison of Median Water Quality Parameters among REC Source of Flow Classes.......................... 28 Comparison of Median Water Quality Parameters among REC Land Cover Classes ............................... 29 Comparison of Median Water Quality Parameters among REC Stream Order Classes............................. 30 Yearly Changes in Water Temperature at Three Contrasting Sites in the Motueka River Catchment....... 31 Proportion of the Summer Period When Temperature Measurements Halfway Between the Daily Mean and Daily Maximum Met or Exceeded Criteria for Ecosystem Health ............................................ 33 Decline in Ammonium Nitrogen Concentration at the Buller Rv at Longford Site ................................... 35 Increase in Nitrate Nitrogen Concentration at the Motueka Rv at Woodstock Site ................................... 35 Taxa Richness or Number of Types of Invertebrates Typically Found at Each Site.................................. 37 Percentage of Taxa That Belong to the Sensitive Mayfly (Ephemeroptera), Stonefly (Plecoptera) and Caddis Fly (Trichoptera) Groups ........................................................................................................ 39 Average Macroinvertebrate Community Index Sores at Each Site ............................................................ 40 Average Semi-Quantitative Macroinvertebrate Community Index (SQMCI) Scores at Each Site ............ 41 Non-Metric Multi-Dimensional Scaling Ordination Plot Showing the Similarity of Sites and Sampling Occasions Based on the Macroinvertebrate Data ....................................................................................... 43 Comparison of Average Invertebrate Indices among REC Source of Flow Classes .................................. 44 Comparison of Average Invertebrate Indices among REC Land Cover Classes........................................ 45 Comparison of Average Invertebrate Indices among REC Stream Order Classes..................................... 46 Box Plot of Periphyton Scores at Monitoring Sites in the Tasman District ............................................... 47 Proportion of Samples for Which the Periphyton Community Indicator Scores from Each Site That Did, or Did Not, Exceed a Score of 8 ................................................................................................ 48
LIST OF APPENDICES
Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5
Details and REC Classifications of the Core Monitoring Sites Photos of Core Monitoring Sites Environmental Performance Indicators Used in the Surface Water Quality Monitoring Programme Box Plot Summaries of Water Quality at Each Site Mean and Range of Invertebrate Indices at Each Site
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LIST OF ABBREVIATIONS DRP ­ dissolved reactive phosphorus Ck - creek d/s ­ downstream E. coli ­ a faecal indicator bacteria FSS ­ fixed (inorganic) suspended solids ICM ­ Integrated Catchment Management research programme MCI ­ Macroinvertebrate Community Index NH4-N ­ Ammonium nitrogen NIWA ­ National Institute of Water & Atmospheric Research NO3-N ­ Nitrate nitrogen NRWQN ­ National River Water Quality Network REC ­ River Environment Classification RMA ­ Resource Management Act Rv - River SoE ­ State of the Environment SQMCI ­ Semi-quantitative Macroinvertebrate Community Index Stm - Stream SWQMP ­ Tasman District Council's Surface Water Quality Monitoring Programme TDC ­ Tasman District Council TN ­ total nitrogen TP ­ total phosphorus TRMP ­ Tasman Resource Management Plan TSS ­ Total suspended solids u/s ­ upstream VSS ­ volatile (organic) suspended solids ACKNOWLEDGEMENTS Tasman District Council and Cawthron would like to thank people and organisations who have assisted in this monitoring programme. In particular we would like to thank landowners who provide access to monitoring sites, National Institute for Water and Atmosphere for data from National Water Quality Network sites, Dinah Grew of TDC for formatting and TDC hydrology department staff who provide field assistance (Martin Doyle, Brenda Clapp, Gordon Curnow, Matt McLarin, Tom Kennedy).
STATEMENT OF DATA VERIFICATION AND LIABILITY
Tasman District Council recognises the importance of good quality data. This first comprehensive surface water quality technical report for the whole District provides interpretation of results from the Tasman District Council Surface Water Quality Monitoring Programme and a summary of relevant information available at time of producing the report. Data collection and management systems follow systematic quality control procedures (see Tasman District Council Surface Water Quality Monitoring Programme). International Accreditation New Zealand (IANZ) laboratories carried out sample analysis excluding field analysis. Expert staff have been involved in each stage of the monitoring process. A process of internal and external review of this report has been implemented. While every attempt has been made to ensure the accuracy of the data and information presented, Tasman District Council does not accept any liability for the accuracy of the information. It is the responsibility of the user to ensure the appropriate use of any data or information from the text, tables or figures. Not all available data or information is presented in the report. Only information considered reliable, of good quality and of most importance to the readers has been included. This information will be expanded and improved over the years. Subsequent "state of the environment" monitoring reports will therefore provide a more complete picture of the state of, and pressures on, the regional environment, along with more extensive links to other resource management agencies.
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1 INTRODUCTION Tasman District Council (TDC) monitors surface water quality to fulfil its responsibilities under the Resource Management Act (RMA 1991) and the Tasman Resource Management Plan (TRMP). The RMA (1991) imparts to regional councils a function of maintaining and enhancing the quality of natural water (Section 30) and directs councils to gather information so that they can effectively carry out these functions (Section 35). The TRMP identifies the degradation of water quality as an issue and seeks to maintain and improve the quality of fresh and marine waters in the District. The TDC's State of the Environment (SoE) monitoring programme aims to gather appropriate data to fulfil these responsibilities. Tasman District covers an area of northern South Island from Golden Bay (including most of Kahurangi National Park in the west), Tasman Bay (including the Motueka River Catchment) to Richmond (near Nelson in the east), to upper Buller (including the lower half of the Maruia River in the south). There are 9,253 kilometres of waterways in the District, over 90% of which are situated in a cool extremely wet or cool wet climate (from Snelder, 2004). Most streams are fed from hills (51%) or low elevations (24%), with mountain-fed waterways making up about 25% of waterways. The influence of geology on waterways is mostly sedimentary (soft sedimentary 38% and hard sedimentary 31%), with 6% alluvium and 21% plutonics. Sixty percent of waterways are dominated by indigenous forest, pasture 17% and exotic forest 9%. Over 77% of waterways are on smaller (first to third order) waterways, with 72% having a high gradient. 1.1 The Pressure-State-Response Model Implementation of TDC's SoE monitoring programme is based on the pressure-stateresponse framework (Figure 1). This framework was used in State of New Zealand's Environment (Ministry for the Environment, 1997) report, and is based on a concept of causality. Human activities exert pressures on the environment, such as pollutant discharges or over-use of a resource, changing both the quality and quantity of natural resources. These changes alter the state or condition of the environment, which can then be assessed by measuring various aspects of the environment. The human responses to these changes include any actual organised behaviour that aims to reduce, prevent or mitigate undesirable changes. Pressures from natural sources are not considered in this framework as they are generally not controllable. Pressure
Response
State
Figure 1 The Pressure-State-Response Model of Environmental Change Under this model SoE monitoring seeks to identify changes in the state of the environment, particularly degraded or declining states, so that the pressures causing the identified changes can be found, allowing the Council to formulate an appropriate response. This model is used in the discussion of results (see Section 6 of this report).
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1.2 Programme Design The Surface Water Quality Monitoring Programme (SWQMP) forms part of the Council's broader SoE monitoring programme. Under this programme data on water quality, periphyton (algae on the stream bottom) and stream invertebrates have been gathered from selected rivers and streams since 1999. Additional information has also been collected during the Council's bathing water surveys and as part of scientific studies carried out by other agencies in the District. The specific aims of the SWQMP are: 1 To determine the quality of surface waters in the District in reference to accepted standards (for public health, recreational and ecological reasons). 2 To identify short and long term trends in water quality (bearing in mind that accurate trend analysis on quarterly data is only achievable after 15-20 years of data collection). 3 To identify cumulative environmental effects from multiple discharges into surface waters. 4 To understand the nature of surface water quality problems/issues in order to provide information that enables defensible management responses to be enacted. Such responses include seeking reviews to Council resource management plans, regulations, and resource consent conditions. 5 To identify new issues and monitoring requirements. 6 To identify factors that cause change in surface water quality (i.e. impact monitoring). The SWQMP was designed to achieve the six aims outlined above. However, the programme must work within a number of constraints. Given the resources available, quarterly sampling is undertaken. Sampling only occurs at base flow so very little is known about water quality after rain or flood flow conditions. For the Contact Recreation Water Quality Monitoring Programme (mostly bathing beaches or swimming holes), sites are sampled biweekly or weekly from November-March irrespective of rainfall. While information from the SWQMP will give clues as to the cause of poor water quality, it is often only after intensive sampling within a catchment that clear conclusions of cause and effect relating to specific land-use activities can be drawn. Such follow-up investigations are undertaken on a prioritised basis. The programme targets areas where the most significant human pressures, such as point source discharges, exist or are suspected, while maintaining a few sites in pristine areas for reference sites (eight sites out of a total of 50). Sites in the programme were chosen to try to achieve a balance within and between the following criteria: (a) geographical spread throughout the District; (b) range of waterway sizes represented (from large main-stem rivers to small creeks);
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(c) range of different environmental pressures represented at different sites; (d) in areas with high human use (such as for recreation or drinking) or significant ecological values. In order to address its aims while working within the constraints mentioned above, design of the SWQMP involved careful choice of indicators (measures) of water quality, sites, and methods. In addition to the intrinsic ecological values of waterways the issue of water quality is also related to community values. Therefore, the choice of environmental indicators may differ between monitoring sites with different values. For example, one stretch of river may be highly valued as a fishery resource, but may be seldom used for swimming, while another may be popular for swimming. In this example water clarity, ammonia and macroinvertebrates would be the most important indicators for a river valued for its fishery, but faecal bacteria (E. coli and faecal coliforms), which are indicators of potential human disease, would be the most crucial indicators at monitoring sites valued for contact recreation. Indicators were, therefore, chosen partly to reflect community values, as well as to be consistent (as far as practical) with indicators recommended by Ministry for the Environment (1998). In this report we summarise information from TDC's SWQMP, along with data from other long-term monitoring programmes in the area, and identify the state of water quality and ecosystem health of rivers and streams throughout the Tasman District. The length of the data record at most of the sampling sites in the District is insufficient for determining trends in the parameters monitored, however, three sites are part of the National River Water Quality Network and have been sampled monthly since 1989, allowing trends to be identified. Further information on the design of the monitoring programme and methods used can be found in the Tasman District Council, Surface Water Quality Monitoring Programme document (January 2005). 2 SAMPLING SITES 2.1 Water Quality Water quality information reviewed here has been collected from 89 sites throughout the Tasman District. However, the analyses presented in this report focus on 70 of these sites, which have been sampled at least three times (Figure 2). Most sites in the SWQMP (Appendix 1) have been sampled on a quarterly basis since late 1999 and thus have been sampled 15-20 times. The main exceptions to this are sites included in the Motueka Integrated Catchment Management (ICM) programme (for further details see http://icm.landcareresearch.co.nz), which have generally been sampled quarterly as part of the SWQMP, but were sampled monthly from October 2000 ­ October 2001 at all flows. Sites sampled as part of bathing water surveys have been monitored weekly/fortnightly each year over the swimming season (November-March). Three sites in the Tasman District (Motueka Rv at Gorge, Motueka Rv at Woodstock, Buller Rv at Longford) are part of NIWA's National River Water Quality Network (NRWQN) and have been sampled monthly since 1989 using a standardised protocol (Smith & Maasdam, 1994).
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The range of parameters that have been measured at each site varies depending on the aims of the particular sampling programme. For example, bathing water surveys involved only spot measurements of faecal indicator bacteria, while sampling at the SWQMP sites was undertaken using the protocols detailed in Tasman District Council's Surface Water Quality Monitoring Programme document (latest revision: January 2005) (see Appendix 3 for an explanation of the variables measured and their applications in terms of assessing the state of the environment). Spot field measurements of temperature, dissolved oxygen, pH, specific conductivity and turbidity were measured using standard meters (YSI 85, YSI 650, Orion 210A, Hach 2100P), while visual water clarity was measured using a black disc (Davies-Colley, 1988). River flow was determined using either; velocity and depth measurements across the river cross-section, or from permanent stage-height recorders at the sites. Samples were collected for laboratory analysis of nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), total nitrogen (TN), dissolved reactive phosphorus (DRP), total phosphorus (TP), total suspended solids (TSS), fixed (inorganic) suspended solids (FSS), volatile (organic) suspended solids (VSS) and faecal indicator bacteria (E. coli). Samples were transported to the Cawthron Institute's IANZ accredited laboratory in chilly bins for analysis. Chemical and microbiological analyses were conducted using standard analytical techniques (APHA, 1998). Recent laboratory reporting limits for the chemical analyses were: NO3-N 0.002 mg/L; NH4-N 0.005 mg/L; TN 0.1 mg/L; DRP 0.005 mg/L; TP 0.005 mg/L, TSS 0.3 mg/L, FSS 0.3 mg/L, VSS 0.3 mg/L and E. coli 5 cfu/100mL. In cases where water quality data were below the reporting limit for a particular chemical analysis we substituted a value of half the reporting limit for the calculation of statistics.
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Figure 2 Water quality monitoring sites throughout the Tasman District NRWQN = National River Water Quality Network sites ICM = Integrated Catchment Management programme sites The quarterly sampling has generally been carried out after at least a short period of stable weather throughout the District and therefore represents "base-flow" conditions. In contrast, the three NRWQN sites are sampled on set days each month and therefore include measurements over a wide range of flow conditions.
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2.2 Macroinvertebrates Aquatic macroinvertebrates are small animals (0.5-60 mm in length) that spend most of their lives in streams, rivers, lakes and wetlands. They include insects (e.g., mayflies, stoneflies, caddis flies, true flies), crustacea (e.g., amphipods), worms and snails. These macroinvertebrates live almost their entire lives in the water, although many of the insects have aerial adult stages. Some are pollution tolerant whereas others are not. As a result, the presence or absence of particular macroinvertebrate species can indicate the ecological health of a site. The macroinvertebrate data reviewed here has been collected at 83 sites throughout the Tasman District (Figure 3). These sites include TDC's SWQMP sites that have been sampled annually in spring since 2000 (four samples) and three NIWA National River Water Quality Network sites that have been sampled annually since 1989 (15 samples). The review also includes sites that were chosen for a 2002 study of macroinvertebrate populations around the Motueka River catchment as part of the ICM research programme. Macroinvertebrate samples were collected after a period of at least two weeks following a rainfall event that elevated flows >2.5 times the base flow. Macroinvertebrate data from TDC's SWQMP sites are calculated from single hand net samples collected from each site (Protocol C1, Stark et al. 2001), whereas the NIWA data is calculated from seven pooled surber samples collected from each site. Three surber samples and a hand net were collected from each site in the ICM macroinvertebrate study. For all macroinvertebrate studies, samples were preserved in the field and then transferred back to the laboratory for taxonomic analysis. Samples were sorted to the lowest possible taxonomic level possible using standard identification keys. Macroinvertebrates from surber samples were counted, whereas relative abundances of each taxa were calculated from hand net samples. Several different indices of river ecosystem health were calculated from the data and include:- Species richness (or more strictly, taxa richness). This is simply the number of different types of animals (= taxa) present. Sometimes the different taxa are resolved down to the species level (e.g., Austroclima sepia), but may be at the genera level (e.g., Austroclima sp.), or even higher taxonomic level (e.g., Leptophlebiidae), depending upon the practicality of identification. In general terms, high species richness may be considered good, though often mildly impacted or polluted rivers with slight nutrient enrichment can have higher species richness than naturally "healthy" streams and rivers. EPT taxa. This is the total number of types of mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddis flies (Trichoptera) found in a sample. These kinds of freshwater insects generally are intolerant of pollution. Two types of caddis flies (Oxyethira, Paroxyethira) are often found in enriched streams and thus were not included in the counts of sensitive EPT species. The percentage of EPT species compared to the total number of species found at a site provide an index of health, with high percentages considered to indicate good health.
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І
Invertebrate Site Type !( State of the Environment $+ NRWQN #* ICM
!(Aorere @ Le Comps
!(Kaituna @ Solleys Rd
!( Aorere @ Devils Boots
Onekaka @ Shambala !(!(Onekaka @ Ironstone
Watercress Ck
!(
!(Motupipi @ Reillys
Anatoki @ Bridge !( !(Takaka @ Kotinga
!(Winters Ck above culvert !(!(!(!(!(!( !(Waingaro @ Hanging Rock
!( Takaka @ Harwoods
!(Riwaka @ Nth Branch Source
#!(!( #**#*!(Motueka @ Woodmans Bend #*
Waiwhero @ Cemetery !( Motueka d/s Graham #*#*#*#*$+#*!( #* Motueka @ Woodstock
!(!(!( !( !( Wangapeka @ Walters Pk
Stanley Brook @ Barkers Motueka u/s Wangapeka
#*#* !( !( !( !(!(!(!( !( Sherrie @ Blue Rock
#*#* #*#* #*#*#* #* !(Sherrie @ Cave
!(Wairoa @ Pig Valley
!(Wai-iti above Hiwipango
#* Motupiko @ Christies #* #* !( Motueka @ Gorge #* #*#* #*#* !(!(!( $+ Kikiwa Strm
$+Buller @ Longford
Matakitaki @ Murchison
Buller @ Lk Rotoiti
!( !( !(!(!( Mangles @ Gorge
Black Valley Strm @ Lk
!(
!( Riwaka @ Hickmotts !( Little Sydney #* #*Brooklyn #* !( Motueka @ Woodmans !( Waimea @ Appleby
!(!( !( Matakitaki @ HoMrsaetaTkeirtarakci [email protected] Nardoo
!( Reservoir Ck !( !( Wai-iti @ Livingston Rd
!( Wairoa @ Irvines
Roding @ Twin Bridges !( !( Lee @ Meads Br.
0 5 10 20 30 40 Kilometres
Figure 3
Macroinvertebrate monitoring sites throughout the Tasman District NRWQN = National River Water Quality Network sites ICM = Integrated Catchment Management programme sites (Periphyton was also monitored at State of the Environment sites)
Macroinvertebrate Community Index (MCI) values were calculated according to the method of Stark (1985, 1993, 1998). The MCI relies on prior allocation of scores (between 1 and 10) to different kinds of freshwater macroinvertebrates based upon their tolerance to pollution. Macroinvertebrates that are characteristic of unpolluted conditions score more highly than those found predominantly in polluted conditions. In theory, MCI values can range between 200 and 0, but in practice it is rare to find MCI values greater than 150. Only extremely polluted or sandy/muddy sites score under 50. This index is designed specifically
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for stony riffle substrates in flowing water, therefore interpretation of scores requires some knowledge of the types of habitat where the samples were collected. SQMCI (Semi-Quantitative MCI) values were also calculated. Unlike the MCI, which only uses presence-absence data, the SQMCI incorporates relative abundances into the index calculation. SQMCI values, therefore, reflect both the abundance and types of macroinvertebrates found at a site and thus respond to more subtle changes in macroinvertebrate community composition than the MCI. 2.3 Periphyton The amount and types of periphyton (or algae) growing on the river bed is also indicative of the river ecosystem health. Excessive growth of filamentous green algae is typical in unshaded sites that have abundant nutrients. These growths are often unsightly and can reduce the quality of habitat for other river life. In more healthy systems periphyton growths are dominated by thin films or mats of brown diatoms, which form an important food source for some types of macroinvertebrates. Periphyton data was only available from TDC's SWQMP sites (Figure 3) and has been measured quarterly since October 2001. Periphyton assessments were based on Rapid Assessment Method 2 (RAM-2) from Biggs & Kilroy (2000). This involves estimating the percentage cover of all algae present, classified according to their appearance (e.g., growthform and colour), at a number of regularly spaced points across five transects. The percentage cover values are weighted according to the pollution tolerance of each algal classification, and are then combined to give an overall score for the site ranging between 1 and 10 (1 indicating a site with highly degraded water quality and a score of 10 indicating a healthy site with good water quality). The TDC's methodology varies from that outlined by Biggs & Kilroy (2000) in that clean substrate is given a score of 10 (along with pollution intolerant classes of algae), rather than scoring 0. 3 WATER QUALITY 3.1 Patterns Across Sites and Exceedance of Guidelines Box plots showing median values and the distribution of data points at each site for each water quality parameter are shown in Appendix 3. These box plots give a detailed summary of the results from each site, but are somewhat difficult to read given the large number of sites. An alternative way of viewing the state of water quality throughout the District is to compare results with guideline water quality values (Table 1). The proportion of the samples collected from each site that either meet or exceed these guidelines is shown in Figures 4-13.
State of Surface Water Quality in Tasman District June 2005
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Table 1
Guideline water quality values for protection of river ecosystem and
human health
Parameter
Guideline Value
Reference
Dissolved oxygen
>80% Saturation or >6.5 mg/L
ANZECC (1992)
pH
5-9
CCREM (1987)
Clarity
>1.6 m
ANZECC & ARMCANZ(2000)
Turbidity
<5.6
ANZECC & ARMCANZ(2000)
Total nitrogen
<0.614 mg/L
ANZECC & ARMCANZ(2000)
Dissolved inorganic nitrogen
<0.444 mg/L
ANZECC & ARMCANZ(2000)
Dissolved reactive phosphorus
<0.01 mg/L
ANZECC & ARMCANZ(2000)
Total phosphorus
<0.033 mg/L
ANZECC & ARMCANZ(2000)
E. coli
<260 cfu/100 mL Acceptable
MfE & MoH (2003)
260-550 cfu/100 mL Alert
>550 cfu/100 mL Action
3.1.1 Dissolved Oxygen Dissolved oxygen concentrations were close to saturation at most sites sampled (Figures 4 and 5). The only site with consistently low dissolved oxygen was Watercress Ck at u/s factory. This was not surprising considering the spring-fed nature and the abundant growth of aquatic plants in this stream. Dissolved oxygen concentrations were occasionally also low in Waiwhero Ck, but these low concentrations coincided with periods of extremely low (or zero) flow. Occasional low measurements at other sites may also have been the result of seasonal low flows.
State of Surface Water Quality in Tasman District June 2005
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Figure 4 Proportion of dissolved oxygen (% Saturation) measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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Figure 5 Proportion of dissolved oxygen (mg/L) measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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3.1.2 pH Measurements of pH at most sites were also generally within the guidelines (Figure 6). The few exceedances were found in the western tributaries of the Motueka River (Wangapeka, Graham River, Riwaka), which drain karst (marble) terrain. Water draining this terrain becomes enriched in carbonates, resulting in the high pH recordings.
Figure 6 Proportion of pH measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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3.1.3 Nitrogen Concentrations of total nitrogen and dissolved inorganic nitrogen (nitrate nitrogen plus ammonium nitrogen) exceeded guideline values regularly at some sites (Figures 7 and 8). Particularly high concentrations were observed at Reservoir Ck (particularly downstream of Salisbury Rd), Motupipi Rv at Reillys, Winter Ck, Stanley Brook at Barkers, Wai-iti Rv at Livingstone Rd, and Wai-iti Rv at Pigeon Valley Bridge. The Reservoir Ck and Winter Ck sites are heavily influenced by urban land use. The Motupipi River also had very high coverage of the bed with aquatic plants, which is also partly due to its spring-fed character with stable flow conditions. The catchment is predominantly in pastoral farming. No obvious improvement in total nitrogen could be determined from results for Motupipi Rv at Reillys following wastewater treatment upgrades at the dairy factory in 2003-03. The single sample taken at Takaka Rv at Paynes Ford also contained high concentrations of total nitrogen and dissolved inorganic nitrogen (Appendix 3.5 ­ 3.7). Other sites with moderate to high concentrations of the various forms of nitrogen include Kikiwa Stm, Little Sydney Ck, Motueka Rv at McLeans, Waimea Rv at Appleby, Waiwhero Ck, and Watercress Ck u/s of the factory (Appendix 3.5 ­ 3.7). MacGibbon (2000) and Roberts (1993) showed that nitrate-nitrogen concentrations were very low in the headwaters of the Takaka River and gradually increased downstream. MacGibbon showed they peaked at 0.46 gm-3 at Paynes Ford. However, the headwaters site recorded higher ammonia-nitrogen, phosphorus and conductivity levels than most other sites; the reason for this is not known. The Paynes Ford results for periphyton and macroinvertebrates indicated poor condition. These results could have been due to poorly performing toilets. These facilities were upgraded after this issue was raised. A marked reduction in water clarity was measured between the Takaka River headwaters site and the Harwoods site approximately 15 kilometres downstream of the Cobb Power station discharge. Nutrient concentrations in the Waikoropupu River are consistently relatively high over 10 years from 1990 to 1999 (nitrate range: 0.1-0.9 gm-3) (Tasman District Council springs monitoring programme, unpublished data).
State of Surface Water Quality in Tasman District June 2005
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Figure 7 Proportion of total nitrogen measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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Figure 8 Proportion of dissolved inorganic nitrogen measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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3.1.4 Phosphorus Concentrations of total phosphorus (TP) and dissolved reactive phosphorus (DRP) regularly exceeded guidelines for control of algal growth at a relatively large proportion of sites throughout the District (Figures 9 and 10). Regular exceedance of TP and DRP guidelines occurred at both Reservoir Ck sites, Kikiwa Stm, Little Sydney Ck, Motupipi Rv at Reillys, Waiwhero Ck, Watercress Ck u/s of the factory, and Winter Ck (Appendix 3.8). Concentrations of DRP also regularly exceeded guideline values at Kikiwa Ck, Hunters Ck, Motupiko Rv at Christies, Motupiko Rv at Quinneys, Baton Rv, Motueka Rv at McLeans, Pearse Rv, Riwaka Rv at Hickmotts, Kaituna Rv at Sollys, Tiramea Rv at Track, and Wai-iti Rv above Hiwipango.
State of Surface Water Quality in Tasman District June 2005
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Figure 9 Proportion of total phosphorus measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
Page 17
Figure 10 Proportion of dissolved reactive phosphorus measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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3.1.5 Clarity and Turbidity Water clarity was high (and turbidity low) at most sites throughout the District and the clarity guidelines were only rarely exceeded for the majority of sites (Figures 11 and 12). Exceptions to this were Winter Ck and the two sites on Reservoir Ck which consistently have poor water clarity. Kikiwa Stm, Little Sydney Ck and Waiwhero Ck also have relatively low water clarity (Appendix 3.11). The long sampling record at the NRWQN sites (Motueka Rv at Gorge, Motueka Rv at Woodstock, Buller Rv at Longford) means that a considerable number of samples have been collected under high flow conditions and water clarity at these times is often low (Figure 11, Appendix 3.11). Clarity at Motupipi River is much lower than expected for a spring-fed creek. For interest the maximum recorded water clarity of the Waikoropupu Springs was 62m (NIWA, 1993).
Figure 11 Proportion of water clarity measurements at each site that met or exceeded guidelines
State of Surface Water Quality in Tasman District June 2005
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Figure 12 Proportion of turbidity measurements at each site that met or exceeded guidelines 3.1.6 Faecal Indicator Bacteria Concentrations of E. coli regularly exceeded the "action" limit guideline for contact recreation at Kikiwa Stm, Little Sydney Ck, Mole Ck at Bridge (near Murchison), Motupipi Rv at Reillys, both Reservoir Ck sites, Sherry Rv at Blue Rock, Sherry Rv at Matariki Bridge, Onekaka Rv at Shambala, Watercress Ck u/s factory, and Winter Ck (Figure 13; Appendix 3.10). The catchments of these waterways are dominated by dairy or sheep/beef farming or urban (Reservoir Ck). Nottage (2000) showed E. coli loadings in the Aorere Rv tributary, Kaituna Rv at Sollys had loadings of over 130 Billion E. coli during one 3 hour rainfall event.
State of Surface Water Quality in Tasman District June 2005
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Figure 13a Proportion of faecal indicator bacteria measurements at each site that met or exceeded guidelines for contact recreation
State of Surface Water Quality in Tasman District June 2005
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Figure 13b Proportion of faecal indicator bacteria measurements at each site that met or exceeded guidelines for stock drinking.
State of Surface Water Quality in Tasman District June 2005
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3.2 Site Groupings
Figure 14
To identify groups of sites with similar characteristics a hierarchical cluster analysis was conducted using the water quality data. This technique considers all the different water quality parameters together and calculates a "distance" between sites depending on their similarity in terms of water quality. All variables were log transformed to improve the normality of the data before analysis. The cluster analysis identified three distinct groupings of sites ­ red sites, yellow sites, and green sites (Figure 14).
Buller @ Longford Buller @ Lake Matakitaki @ Nardoo Motueka @ Gorge Waingaro @ Hanging Rock Wairoa @ Pig Valley Wangapeka u/s Dart Takaka @ Harwoods Sherry @ Cave Graham Strm Hunters Strm Tiraumea @ Track Wai-iti above Hiwipango Baton @ Bridge Motueka @ Woodstock Motueka @ Woodmans Bend Wangapeka @ Walters Wairoa @ Irvines Motueka d/s Graham Motueka u/s Wangapeka Takaka @ Kotinga Aorere @ La Comps Matakitaki @ Horse Terrace Matakitaki @ Murchison Glenroy @ Bridge Aorere @ Devils Boots Roding @ Twin Bridges Lee @ Meads Riwaka @ Northbranch Source Waimea @ Appleby Onekaka u/s Ironstone Ck Motupiko @ Christies Mangles @ Gorge Riwaka @ Hickmotts Kaituna @ Solleys Onekaka @ Shambala Sherry @ Blue Rock Wai-iti @ Livingston Bridge Wai-iti @ Pigeon Valley Stanleybrook Black Vly d/s Borlase Ck Black Vly @ Lake Watercress Creek Motupipi @ Reillys Winter Creek Reservoir Ck d/s Salisbury Rd Reservoir Ck u/s Marlborough Cr Waiwhero @ Cemetery Kikiwa Stream Little Sydney
0
1
2
3
Distances
Clustering of the sites based on their water quality
A Principal Components Analysis (PCA) was used to help identify the characteristics that separated each group of sites. PCA is a statistical technique used to condense many variables down to a more manageable number of pseudo-variables (or principal components). Variables that are highly correlated with each other are essentially combined into one principal component. The first principal component (PC1) explained 53.1% of the total variance in the data and was highly correlated with turbidity, water clarity and the concentrations of nitrogen, phosphorus and faecal indicator bacteria. The second principal component (PC2) explained 17.6% of the variance in the data and was highly correlated with pH, conductivity and the concentration of dissolved oxygen. A plot of the principal component scores for each site is shown in Figure 15. Sites with similar characteristics are plotted closely together, while those with markedly different characteristics are plotted far apart. The "red" sites tend to be at the right-hand side of the ordination (Figure 15) indicating that these sites tend to have poor water clarity and high concentrations of nutrients and faecal indicator bacteria compared with other sites throughout the District. These sites are
State of Surface Water Quality in Tasman District June 2005
Page 23
typically the ones that exceeded the water quality guidelines discussed above (Section 3.1). Most of these sites are small streams draining lowland areas that have been intensively developed for agriculture or urban usage. The yellow sites are roughly in the middle of the ordination (Figure 15) indicating that their water quality is intermediate between the poor quality (red) sites and the high quality (green) sites. The yellow sites include both small streams (e.g., Black Valley Stm) and moderatesized rivers (Riwaka Rv at Hickmotts, Sherry Rv at Blue Rock, Mangles Rv at Gorge) and also tend to drain areas that are intensively developed for agriculture. It is notable that many of these yellow sites are downstream of "green" sites with higher water quality (e.g., Riwaka Rv at Hickmotts is downstream of Riwaka Rv at Northbranch Source, Sherry Rv at Blue Rock is downstream of Sherry Rv at Cave, Onekaka Rv at Shambala is downstream of Onekaka Rv upstream of Ironstone Ck, Mangles Rv at Gorge is downstream of Tiramea Rv at Track, and Wai-iti Rv at Livingston Rd and Wai-iti Rv at Pigeon Valley are downstream of Wai-iti Rv above Hiwipango. The "green" sites have the highest water quality and include forested headwater sites and also downstream reaches of the large rivers in the District (e.g., Motueka, Takaka, Aorere, Buller, Waimea).
High pH High conductivity Higher oxygen
PC2 (17.6%)
2
Riwaka @ Northbranch Source
Winter Ck
Onekaka u/s Ironstone
Roding @ Twin Bridges
Riwaka @ Hickmotts
1
Lee @ Meads
Motueka d/s Graham
Wangapeka @ Walters
Motupipi @ Reillys
Res Ck d/s Salisbury Rd
Res Ck u/s Marlborough Cr
Motueka @ Woodstock Motueka @ WoodmansOnekaka @ Shambala
Wangapeka u/s Dart
Waimea @ Appleby
Little Sydney
Takaka @ Kotinga
Motueka @ GorgGelenroy @ Br
Mangles @ GKoargiteuna @ Solleys
0
Wairoa @ Irvines Wai-iti @ Pigeon Vly Waingaro Takaka @ Harwoods
Wai-iti @ Livingstone Rd Sherry @ Blue Rock
Matakitaki @ Horse Terace
Motueka u/s Wangapeka
Aorere @ La Comps
Black Vly @ Lake
Aorere @ Devils BootMs otupiko @ Christies Black Vly ds Borlase Ck
-1Matakitaki @ Nardoo
Tiraumea @ T
Buller @ Longford
Sherry @ Cave
Waiwhero @ Cemetery Kikiwa Strm
Stanleybrook
-2
Buller @ Lake
Graham Strm
Lower pH Low conductivity Lower oxygen
-3 -2
Clear water Low nutrients Low bacteria
Hunters Strm
-1
0
1
PC1 (53.1%)
Watercress Ck
2
3
Turbid water High nutrients High bacteria
Figure 15 Ordination of sites based on their water quality The colours refer to the site groupings from Figure 14 above.
State of Surface Water Quality in Tasman District June 2005
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3.3
Water Quality in Relation to the River Environment Classification Groupings
3.3.1 The REC System
The Ministry for the Environment, in conjunction with NIWA, has recently developed the New Zealand River Environment Classification (REC) system (Snelder et al., 2004). The REC groups rivers, or parts of rivers, at six hierarchical levels according to their climate, source of flow, geology, land cover, network position and valley landform. This system allows sections of rivers that are similar with respect to these factors to be grouped together for management purposes. The first four factors relate to the characteristics of the catchment upstream, while the factors of network position and valley landform are more specifically related to the site of interest. Within each factor there are a series of categories that are used to describe reaches of rivers throughout the country (Table 2).
Table 2
Summary of factors and categories used in the REC classification
(from Snelder, 2004)
Factor
Categories
Code Criteria
Climate
Warm extremely wet
WX
Mean annual temperature:
Warm wet
WW
Warm 12 °C
Warm dry
WD
Cool 12 °C
Cool extremely wet
CX
Mean annual effective precipitation:
Cool wet
CW
Extremely wet 1500 mm
Cool dry
CD
Wet 500-1500 mm
Dry 500 mm
Source of flow Glacial Mountain
GM
% permanent ice:
Mountain
M
Glacial Mountain >1.5%
Hill
H
Rainfall volume in elevation categories:
Low elevation
L
Mountain >50% above 1000 m
Lake
Lk
Hill 50% between 400 ­ 1000 m
Spring
Sp
Low elevation 50% below 400 m
Regulated
R
Lake influence index
Wetland
W
Others manually assigned
Geology
Alluvium
Al
Spatially dominant geology category, unless:
Hard sedimentary
HS
soft sedimentary >25%, then classified as soft
Soft sedimentary
SS
sedimentary
Volcanic basic
VB
Volcanic acidic
VA
Plutonic
Pl
Miscellaneous
M
Land cover
Bare
B
Spatially dominant land cover class, unless:
Native forest
IF
pasture >25%, then classified as pasture
Pastoral
P
urban >15% then classified as urban
Tussock
T
Scrub
S
Exotic forest
EF
Wetland
W
Urban
U
Network
Low order
L
Stream order:
position
Middle order
M
Low = 1 and 2
High order
H
Medium = 3 and 4
High >5
Valley landform High gradient
H
Valley slope:
Medium gradient
M
High >0.04
Low gradient
L
Medium 0.02 ­ 0.04
Low <0.02
State of Surface Water Quality in Tasman District June 2005
Page 25
The source of flow categories of "spring", "regulated" and "wetland" have not been developed for Tasman District at this stage. There are a large number of karst springs in the district particularly in Mt Arthur marble country. Waikoropupu Springs is one of the world's largest cold-water springs with a mean flow of 13.2 m3/sec with a stable mean temperature of 11.7oC. The spring arises from one of the most important karst aquifers in New Zealand in terms of volume of water storage, the Takaka Valley. The marble aquifer extents for 180m2 and is well over 500m thick. The average flow in the Takaka River is 16.1 m3/sec but it loses up to 10-11 m3/sec in its middle reaches. The river regularly dries up in summer. Waterways with flow regulated include the Cobb/Takaka and Onekaka River Hydro schemes. There are a number of small dams on ephemeral streams, particularly in the Moutere, that are used for irrigation and may increase flows during drier periods. Geology plays an important role in shaping aquatic communities particularly in the upper Motueka catchment where there are high concentrations of the heavy metals iron, nickel and chromium in stream sediment due to weathering of ultramafic rock. This occurs to a lesser extent in other streams draining the Red Hills in the eastern part of the district. Rivers draining marble geology have substantial low flows compared to Moutere Gravels.
3.3.2 Interpreting Water Quality Data With Respect to REC Groupings
Using the REC system it is possible to classify sites in a number of ways according to their climate, source of flow, geology, land cover, network position, and valley landform classes. Median values for each water quality parameter from each site were calculated and then combined together to show the range of water quality within each REC classes. There is a considerable amount of intercorrelation among the different REC classes. For example, low elevation land is much more likely to have been developed into pasture than high elevation land. Therefore, Significant differences among sites with different source of flow classes are likely to be due to differences in land cover rather than a direct effect of source of flow. Given the problems of intercorrelation among REC classes only comparisons among three REC classes; source of flow, land cover and network position (or stream order) are presented here. Statistical comparisons among REC classes for each water quality parameter were made using non-parametric Kruskal-Wallis tests, which are not influenced by nonnormal data distributions.
Significant differences among source of flow classes were found for pH, total nitrogen, nitrate nitrogen, ammonium nitrogen, dissolved reactive phosphorus, total phosphorus, E. coli, water clarity, and turbidity. Sites draining low elevation land had higher concentrations of TN, NO3-N, NH4-N, DRP, TP, E. coli, and suspended sediments than sites draining hill country, mountains or flowing from a lake (Figure 16*). As mentioned above, these differences are probably due to differences in land cover rather than a direct effect of source of flow.
Significant differences were also found among the land cover classes for dissolved oxygen, pH, TN, NO3-N, NH4-N, DRP, TP, E. coli, clarity, turbidity, and suspended sediments. Concentrations of nutrients, E. coli and suspended sediment at sites classified as having pastoral land cover were higher than at sites with indigenous
State of Surface Water Quality in Tasman District June 2005
Page 26
forest or exotic forest land cover. Similarly, water clarity was lower at pastoral sites than in forested sites. The one stream classified as being urban (Watercress Creek) appeared to be similar to the pastoral streams in terms of water quality but had lower oxygen concentrations and pH than sites in the other classes (Figure 17). The effects of land use on water quality are widely recognised and the results of this review are consistent with earlier nationwide studies of water quality patterns (Larned et al., 2004). Oxygen saturation, water clarity, turbidity and the concentrations of TN, NO3-N, DRP, and TP varied significantly among REC stream order classes. Oxygen saturation was lowest in first order streams, while concentrations of nutrients tended to be highest in the smaller streams (Figure 18). This result is somewhat contrary to the perception that small headwater streams are generally more healthy than larger lowland rivers. However, this result is related to the high proportion of small streams in the sampling programme which drain areas that are heavily developed (e.g., Reservoir Ck, Watercress Ck). The large rivers in the Tasman District generally have good water quality, probably due to the fact that much of their flow originates from areas of indigenous forest and thus run-off from developed lowland tributaries is diluted.
*Interpretation of Box Plots
Measured values
outer fence Inner fence
Extreme value
Outlier Whisker: largest value within inner fence Upper quartile
Median value
Range within which the central 50% of values fall (interquartile range)
Box and whisker plots illustrate how data are distributed around the central, or median, value. The `box' represents the range of the central 50% of values around the median, which is shown as the line through the box. Values that are further from the median are illustrated by whiskers, outliers or extreme values, depending on how far the value is from the median and on the size of the interquartile range. The `inner fence' is located 1.5 x the interquartile range from the median, and the `outer fence' is at 3 x the interquartile range.
Lower quartile
If only one data value has been collected, then the value appears as a single line (i.e. as the median value).
Inner fence
State of Surface Water Quality in Tasman District June 2005
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Figure 16
110
2.0
1000
105
H = 5.8
1.8
H = 25.0
900
H = 28.3
100
NS
1.6
p < 0.0001
800
p < 0.0001
95
1.4
700
E. coli (cfu/100 mL)
NO3-N (mg /L)
DO (% Saturation)
90
1.2
600
85
1.0
500
80
0.8
400
75
0.6
300
70
0.4
200
65
0.2
100
60
h
l
lk
m
Source of Flow
0.0
h
l
lk
m
Source of Flow
0
h
l
lk
m
Source of Flow
8.6
0.040
12
8.4
H = 9.2
0.035
H = 21.8
8.2
p < 0.05
p < 0.0005
10
0.030
8.0 8
0.025 7.8
H = 12.5 p < 0.01
Clarity (m)
NH4-N (mg/L)
pH
7.6
0.020
6
7.4
0.015
4
7.2
0.010
7.0 2 0.005 6.8
6.6
h
l
lk
m
Source of Flow
280
0.000 0.040
h
l
lk
m
Source of Flow
0
h
l
lk
m
Source of Flow
12
260
H = 4.1
0.035
H = 17.8
240 NS
p < 0.001
10
220
0.030
200
8
180
0.025
H = 7.1 NS
TSS (mg/L)
DRP (mg/L)
Conductivity (µS/cm)
160
0.020
6
140
120
0.015
100
4
80
0.010
60
2
0.005
40
20
h
l
lk
m
Source of Flow
0.000
h
l
lk
m
Source of Flow
0
h
l
lk
m
Source of Flow
Comparison of median water quality parameters among REC Source of flow classes. h = hill country, l = low elevation, lk = lake, m =
mountain. H-statistics and p-values from the Kruskal-Wallis tests are shown for each water quality parameter. Water quality
guidelines are shown with dotted lines where appropriate.
State of Surface Water Quality in Tasman District June 2005
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Figure 17
110
2.0
1000
105
H = 22.3
1.8
H = 20.3
900
H = 25.2
p < 0.0005
p < 0.0005
p < 0.0001
100
1.6
800
95
1.4
700
E. coli (cfu/100 mL)
NO3-N (mg /L)
DO (% Saturation)
90
1.2
600
85
1.0
500
80
0.8
400
75
0.6
300
70
0.4
200
65
0.2
100
60
if
p
ef
s
u
0.0
if
p
ef
s
u
0
if
p
ef
s
u
Land Cover 8.6
0.040
Land Cover
Land Cover 12
8.4
H = 12.7
H = 21.7
p < 0.05
0.035
H = 16.9
10
p < 0.0005
8.2
0.030
p < 0.005
8.0 8
0.025 7.8
Clarity (m)
NH4-N (mg /L)
pH
7.6
0.020
6
7.4 0.015 4 7.2 0.010 7.0 2 0.005 6.8
6.6
if
p
ef
s
u
Land Cover 280
0.000 0.040
if
p
ef
s
u
Land Cover
0
if
p
ef
s
u
Land Cover 12
260
H = 6.4
0.035
H = 14.3
H = 20.1
240
NS
p < 0.01
10
p < 0.001
220
0.030
200 8
180
0.025
TSS (mg/L)
DRP (mg/L)
Conductivity (µS/cm)
160
0.020
6
140
120
0.015
4 100
80
0.010
60
2
0.005
40
20
if
p
ef
s
u
Land Cover
0.000
if
p
ef
s
u
Land Cover
0
if
p
ef
s
u
Land Cover
Comparison of median water quality parameters among REC Land cover classes. if = indigenous forest, p = pasture, ef = exotic forest,
s = scrub, u = urban . H-statistics and p-values from the Kruskal-Wallis tests are shown for each water quality parameter. Water
quality guidelines are shown with dotted lines where appropriate.
State of Surface Water Quality in Tasman District June 2005
Page 29
Figure 18
110
2.0
1000
105
1.8
H = 12.5
900
H = 6.5
100
1.6
p < 0.05
800
NS
95
1.4
700
E. coli (cfu/100 mL)
DO (%Saturation)
90
1.2
600
NO3-N (mg/L)
85
H = 17.7
1.0
500
p < 0.005
80
0.8
400
75
0.6
300
70
0.4
200
65
0.2
100
60
1
2
3
4
5
6
Order
8.6
0.0 0.040
1
2
3
4
5
6
Order
0 12
1
2
3
4
5
6
Order
8.4
H = 8.1
0.035
H = 6.2
H = 16.0
NS
NS
10
p < 0.01
8.2
0.030
8.0 8
7.8
0.025
Clarity (m)
NH4-N (mg /L)
pH
7.6
0.020
6
7.4 0.015 4 7.2
0.010
7.0
2
6.8
0.005
6.6
1
2
3
4
5
6
Order 280
0.000 0.040
1
2
3
4
5
6
Order
0
1
2
3
4
5
6
Order 12
260
H = 6.6
0.035
H = 13.6
H = 10.0
240
NS
p < 0.05
10
NS
220
0.030
200 8
180
0.025
TSS (mg/L)
DRP (mg/L)
Conductivity (µS/cm)
160
0.020
6
140
120
0.015
4 100
80
0.010
60
2
0.005
40
20
1
2
3
4
5
6
Order
0.000
1
2
3
4
5
6
Order
0
1
2
3
4
5
6
Order
Comparison of median water quality parameters among REC stream order classes. Two first order streams join to form a second
order stream, two second order streams join to form a third order stream etc. H-statistics and p-values from the Kruskal-Wallis tests
are shown for each water quality parameter. Water quality guidelines are shown with dotted lines where appropriate.
State of Surface Water Quality in Tasman District June 2005
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3.4 Water Temperature Temperature loggers (Onset StowAway Tidbit or TruTrack TH-R) have been deployed at 23 sites in the Motueka Catchment as part of the ICM programme. A logger has also been deployed in the lower reaches of the Owen River as part of Cawthron's backcountry fishery research. These loggers were programmed to record temperature every hour and operated from at least March 2001 to February 2002. An example of the full temperature record at three contrasting sites is shown in Figure 19. The Motupiko Rv at Christies site experienced very warm temperatures in summer and very cold temperatures in winter. The Motueka Rv at Gorge site had similar cold temperatures in the winter but water temperatures in the summer were much cooler than in the Motupiko Rv. The Graham Rv drains marble terrain and thus much of the water spends time underground before flowing down the river. Therefore, temperatures at this site remained relatively constant throughout the year, with cool water temperatures in the summer and relatively warm temperatures in the winter. It is also worth noting the large daily fluctuations in temperature at the Motupiko Rv at Christies site in the summer, compared with the relatively small daily variations in the Graham River.
Figure 19 Yearly changes in water temperature at three contrasting sites in the Motueka River catchment The main concerns with water temperature are the effects of high temperatures on aquatic life. Some species will only tolerate relatively cool water and may become stressed or die if temperatures become too high. For example, laboratory studies indicate that brown trout growth is optimal at 13°C (Elliott 1994). However, trout will cease feeding once temperatures climb above 19°C and they will begin to die once temperatures climb above 25°C for a sustained period (Elliott, 1994; Jowett, 1997). Trout cannot tolerate temperatures above 30°C for even a short period. Quinn et al. (1994) examined the temperature tolerances of 12 types of freshwater invertebrates and found that LT50 values (i.e. the temperature at which 50% of animals died after 96 hours) under constant temperature conditions ranged from 22.6°C to 32.4°C. New Zealands' most common mayfly, Deleatidium, was the most sensitive species tested. Cox and Rutherford (2000) extended this work and considered the influence of daily temperature fluctuations on temperature tolerances. They found that LT50 values derived at constant temperatures could be compared with values halfway between the daily mean and daily maximum. They also suggest that a safety margin of 3°C should be used when setting
State of Surface Water Quality in Tasman District June 2005
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an acceptable temperature for protecting a particular species. Therefore, in this report the criterion distinguishing acceptable and unacceptable temperatures has been set at 19.6°C (i.e. the LT50 for Deleatidium [22.6°C] minus a 3°C safety margin). Since high temperatures are likely to be a problem only over the summer months, temperature data from the two month period over summer (15 December ­ 15 February) was used for the analysis of temperature patterns. The temperature value halfway between the daily mean and daily maximum was calculated at each site on each day during this two month period. The proportion of this summer period when this statistic was above or below the acceptable temperature criteria is shown in Figure 20. Eleven of the 23 sites never exceeded the temperature criterion for protecting ecosystem health (Young et al, in press; Figure 20). The most regular temperature exceedances were in Waiwhero Ck (35% of the two month period), Tadmor Rv (27%), Little Sydney Ck (24%) and Motueka Rv at Woodmans Bend (18%). The effects of cool tributaries on water temperatures in the Motueka River are shown in the middle offset box (Figure 20). Temperatures exceeded the criterion occasionally in the Motueka Rv at Woodstock, but the cool waters from the Pearse and Graham rivers prevented the criterion from being exceeded in the Motueka Rv downstream of the Graham River. The effects of land use are demonstrated in the bottom offset box (Figure 20). Graham Stm and Hunter Ck are heavily shaded by pine forest and native forest respectively, and temperatures did not exceed the criterion during the recording period. However, the neighbouring Kikiwa Ck site with similar source of flow, flow rate, geology, network position and landform, drains pastoral land and there is little shading. The temperature criterion was often exceeded at this site (Figure 20). Thermal buffering in sites draining marble geology was due to strong connections to groundwater. Daily amplitude and rate of temperature change were found to be similar across all geologies for the same land cover. Stream temperature at small stream sites were more strongly influenced by land cover. Land cover also affects flow, and in pasture catchments that are unshaded, this can lead to even greater temperatures. A change in land use from pasture to pine forest in a Moutere gravel catchment caused the period without flow to increase from two to five months (Fahey et al 2004). However, shading from pine forest resulted in more moderate temperatures. In addition to the study above, a temperature logger were placed in Reservoir Ck at Salisbury Road. This recorded a maximum of 28°C on 4 February 2005. Subsequently two further loggers were placed upstream at the Marlborough Cres site. The difference between the daily mean and daily maximum at these sites from 24 February to 24 March was: Salisbury Road: 21.5°C, Kareti Drive 21.5°C and Marlborough Crescent 17.5°C. The Kareti Drive site showed the highest temperatures (maximums consistently 1-2 degrees higher than Salisbury Road but overnight-lows were regularly 3°C lower). The higher maximums could be due to the heat generated from the long length of unshaded rock armouring in the bed and banks upstream of this site and high concentrations of suspended solids due to earthworks upstream. The relatively high overnight-low at the Salisbury Road site may be higher due to the Templemore Pond upstream.
State of Surface Water Quality in Tasman District June 2005
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Figure 20 Proportion of the summer period when temperature measurements halfway between the daily mean and daily maximum met or exceeded criteria for ecosystem health
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3.5 Trends at National River Water Quality Network Sites Water quality samples have been collected monthly at the National River Water Quality Network sites since January 1989 and thus provide a sufficient number of data points for trends to be calculated. Trends were determined using nonparametric Seasonal Kendall trend statistics, which compute the slope (or magnitude) and significance of any trends in the data. As the name suggests, seasonal variations in water quality are accounted for by this technique. These statistics have been used previously in New Zealand to analyse trends in the records from the National River Water Quality Network and are described fully in Smith et al. (1996). Following Vant and Wilson (1998), a Microsoft Excel spreadsheet was used to calculate the slopes and significance of any trends in the data. Analyses were initially conducted on the raw data. Some water quality variables are strongly affected by varying flows, therefore it was appropriate to adjust data according to the flows when it was collected. This "flow adjustment" procedure involved the determination of the relationship between flow and the water quality variable, this giving the expected value corresponding to the flow at the time of sampling. The difference between this expected value and the measured value gave the flow-dependent residual. The sum of this residual and the median value of the raw data gave the flow adjusted value of the variable. Flow adjustment was only conducted on variables that displayed clear relationships with flow. The concentrations of ammonium nitrogen showed significant declines at all three NRWQN sites over the course of the record (Figure 21, Table 3). These declines were all relatively large, with changes in relative slope of between 4.4-10.9% per year of the median values (Table 3). Total nitrogen concentrations increased significantly at all three sites over the record, with changes in relative slope of around 2% per year of the median values at each site (Table 3). The fact that these changes have been observed at all three sites including Motueka Rv at Gorge (which is not influenced by human land use) perhaps indicates that these trends are the result of long-term changes in climate rather than changes in land management. Nitrate nitrogen concentrations increased at the Motueka Rv at Woodstock site over the record (Figure 22, Table 3). No changes in nitrate concentrations were observed at the other two NRWQN sites, so it is possible that this increase is due to changes in land management within the Motueka River catchment.
State of Surface Water Quality in Tasman District June 2005
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NH4-N (mg/m3)
18 16 14 12 10 8 6 4 2 0 1989
1991
1993
1995
1997
1999
2001
2003
Figure 21 Decline in ammonium nitrogen concentration at the Buller Rv at Longford site
600
500
NO3-N (mg/m3)
400
300
200
100
Figure 22
0 1989
1991
1993
1995
1997
1999
2001
2003
Increase in nitrate nitrogen concentration at the Motueka Rv at Woodstock site
State of Surface Water Quality in Tasman District June 2005
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Table 3
Significant (p < 5%) trends in water quality parameters at the NRWQN
sites
Site
WQ Parameter
Slope
Relative p-value
slope
(%)
Motueka Rv @ Woodstock (NN1) Ammonium nitrogen
-0.20
-4.36
<0.001
Total Nitrogen
3.8
1.97
0.363
Nitrate nitrogen
2.81
2.61
0.148
Conductivity*
0.24
0.21
2.3
Motueka Rv @ Gorge (NN2)
Ammonium nitrogen
-0.22
-7.58
<0.001
Total nitrogen
1.01
1.98
1.4
Dissolved oxygen (% Sat.)
0.06
0.06
0.039
Dissolved reactive phosphorus
0.037
1.42
0.35
Total phosphorus
0.062
1.54
0.19
Clarity*
0.16
1.55
0.64
Buller Rv @ Longford (NN5)
Ammonium nitrogen
-0.35
-10.90
<0.001
Total nitrogen
1.72
2.2
0.007
Clarity*
0.1286
3.52
<0.001
The slope in Table 3 indicates the size of the trend in water quality units per year, while the relative slope indicates the trend per year as a percentage of the median value for that parameter. The significance of the trends is shown with the p-value. Parameters that were flow adjusted before analysis are shown with an asterisk.
Water clarity increased significantly over the length of the data record at the Motueka Rv at Gorge and Buller Rv at Longford sites (Table 3), and there was also an indication of increasing water clarity at the Motueka Rv at Woodstock site, although the slope was not quite significant at the 5% level (slope 0.047, relative slope 1.24, p = 7.5%). Improvements in water clarity have been found at many other sites throughout New Zealand (Scarsbrook et al., 2003; Larned et al., 2004) and have been related to long-term influences of climate rather than improvements in land management (Scarsbrook et al., 2003).
An increase in conductivity has been observed at many sites throughout the country (Larned et al., 2004) and was also apparent at the Motueka Rv at Woodstock site. However, no significant trends in conductivity were observed at the Motueka Rv at Gorge or Buller Rv at Longford sites.
Significant increases in dissolved oxygen saturation and the concentrations of dissolved reactive phosphorus and total phosphorus were observed at the Motueka Rv at Gorge site (Table 3). The relative slope of the trend in dissolved oxygen saturation was very small (0.06) and therefore is ecologically insignificant. The cause of the increase in dissolved reactive and total phosphate concentrations at this site are unknown, but presumably related to climatic factors, since the catchment upstream of this site is largely undisturbed.
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4 MACROINVERTEBRATES
Figures showing the average and range of various macroinvertebrate indices are shown in Appendix 4. These figures are relatively detailed and require knowledge of the sites to interpret District-wide patterns. To enable easier interpretation of the macroinvertebrate data the results of the sampling have been plotted onto maps of the District (Figures 23-26).
The condition of the aquatic ecology at a site was assessed using all relevant indices listed in Table 4.
Table 4: Criteria for water quality based on macro-invertebrate indices
Macro-invertebrate Index MCI SQMCI Mean number of species Total species Total EPT species
Poor < 100 < 4.2 <9 < 10 <5
Average 100 ­ 110 4.2 ­ 5.0 9 ­ 15 15 ­ 20 9 ­ 15
Good 110 ­ 120 5.0 ­ 6.0 15 ­ 24 20 ­ 30 15 ­ 20
Excellent > 120 > 6.0 > 24 >30 > 20
Taxa richness is a coarse indicator of river ecosystem health and was fairly variable throughout the District (Figure 23). Some of the sites with low taxa richness (Watercress Ck u/s factory, Reservoir Ck) also had poor water quality, which may have been responsible for the low taxa richness. However, very low taxa richness was also found during the single sampling occasion at sites (Motueka right branch, Ellis Stm, Porters Ck) located near the headwaters of the Motueka River, perhaps due to the effects of the ultramafic geology found in the Red Hills area. Very low taxa richness has also been consistently found in the Aorere Rv at Devils Boots and in the Takaka Rv at Kotinga. It is not known why these sites have such low taxa richness. An ecological study of the Takaka River, its tributaries and the Motupipi River was carried out in April 1998 (MacGibbon, 1999). Macroinvertebrate populations were healthy at most mainstem and tributary sites, indicating clean waters or low levels of organic enrichment. The Paynes Ford site recorded impoverished aquatic faunal populations.
State of Surface Water Quality in Tasman District June 2005
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Figure 23 Taxa richness or number of types of invertebrates typically found at each site
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Figure 24 Percentage of taxa that belong to the sensitive mayfly (Ephemeroptera), stonefly (Plecoptera) and caddis fly (Trichoptera) groups Mayflies, stoneflies and caddis flies tend to be sensitive to environmental degradation, therefore the percentage of the taxa at a site comprising these groups provides a relatively sensitive indicator of river ecosystem health. Sites with very low percentages of these EPT taxa (Watercress Ck, Motupipi Rv, Waiwhero Ck, Reservoir Ck; Figure 24) were also identified as having relatively poor water quality. In contrast, sites in the upper parts of most catchments tended to have moderate to high percentages of EPT taxa, indicating good ecosystem health.
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Figure 25 Average macroinvertebrate community index (MCI) scores at each site This scoring system is based on the presence or absence of particular types of macroinvertebrates. The macroinvertebrate community index (MCI) and its semi-quantitative variant (SQMCI) are more refined indicators of river ecosystem health and show very similar patterns throughout the Tasman District (Figures 25 and 26). Sites with low MCI scores (Watercress Ck, Motupipi Rv, Reservoir Ck) typically have poor water quality, which has apparently had an adverse effect on stream life. Low SQMCI scores were also seen in the Rosedale Ck and Waiwhero Ck at cemetery sites (Figure 26). Relatively low MCI and SQMCI scores were also reported from Brooklyn Stm and Little Sydney Ck, which are also both small lowland tributaries draining developed land.
State of Surface Water Quality in Tasman District June 2005
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Figure 26 Average semi-quantitative macroinvertebrate community index (SQMCI) scores at each site. This index is based on the presence/absence and abundance of particular types of macroinvertebrates found at each site. Sites in the inland parts of the District appeared to have healthy stream communities. The low SQMCI score that is reported for the Buller Rv at Lake site is typical of lake outlets and should not be interpreted as indicating poor ecosystem health (Figure 26).
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4.1 Site Groupings Non-metric multidimensional scaling (NMDS) was used to investigate the similarity of sites based on the macroinvertebrate data. Relative abundance data from the 2001, 2002 and 2003 sampling periods was used in the analysis. Relative abundance codes were converted to numerical values corresponding to the lowest values of each class (e.g., abundant = 20). Similarity between sites was calculated using Bray-Curtis distance measure. The NMDS analysis plots samples in two dimensional space such that samples with similar invertebrate communities are plotted close together, while dissimilar samples are plotted far apart (Figure 27). The accuracy of the representation of similarities among sites is represented by the stress value, which in this case was 0.24. The arrangement of sites on the macroinvertebrate NMDS ordination (Figure 27) shows considerable similarity to the ordination of sites based on water quality (Figure 15) suggesting that water quality is an important factor controlling macroinvertebrate community composition. Most of the "red" poor water quality sites were towards the centre/left of the macroinvertebrate ordination and reasonably well separated from the other sites. This was particularly the case for Little Sydney Ck, Watercress Ck, Motupipi Rv, Waiwhero Ck, Reservoir Ck at d/s Salisbury Road and Winter Ck (Figure 27). The main exceptions to this were Reservoir Ck at u/s Marlborough Crescent and Kikiwa Stm, which were both plotted towards the centre of the macroinvertebrate ordination in 2003 and towards the right of the macroinvertebrate ordination in 2001 and 2002, indicating that the macroinvertebrate communities found at these sites were similar to those at the "green" sites with high water quality (Figure 27). The "yellow" sites were considered to have intermediate water quality (Section 3.2) and were also plotted towards the centre/right of the macroinvertebrate ordination, supporting the suggestion that these sites are of intermediate health. The majority of the "green" high water quality sites were plotted at the far right-hand side of the macroinvertebrate ordination and presumably represent high-quality macroinvertebrate communities. Samples collected from the Buller Rv at Lake site were plotted in the centre of the macroinvertebrate ordination and probably reflect the fact that this is the only lake outlet invertebrate community sampled and not necessarily that the community there is impaired. Graham Stm was also considered to be a "green" site in terms of water quality but was consistently plotted in the centre of the macroinvertebrate ordination, perhaps indicating some concerns with the macroinvertebrate community.
State of Surface Water Quality in Tasman District June 2005
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2
Axis 2
[email protected] 01
1 0 -1
[email protected] Rock 02
Motueka u/s Wangapeka 02
WaterCress 01
Riwaka Hickmotts 02 Reservoir Ck u/s Marl Cres 03 Little Sydney 03 Little Sydney 02 [email protected] Rock 03
Kikiwa 02
Stanleybrook 03
[email protected] 03
Wai-iti @ Livingston 03
Black Vly Strm @ Lake 01 [email protected] 01 [email protected] Vly 01 Res Ck u/s Marlborough 01 Kaituna 03
Motupipi 02 Motupipi 03
Waiwhero 03
[email protected] Vly 01 [email protected] 03
[email protected] 03
[email protected] Bend 03
[email protected] 02
Kikiwa 01
Wangapeka u/s Dart 01 [email protected] 01 [email protected] 02 [email protected] 02 [email protected] 02
Waiwhero 01
Graham Strm 02
Wangapeka u/s Dart 02
Black Vly Strm @ Lake 03
Res Ck d/s Salisbury 01
Kikiwa 03
[email protected] 02 [email protected] 01
[email protected] 01
[email protected] Terrace 01
Waiwhero 02 Graham Strm 03
Kaituna 01 Winter Ck 03
Hunters 01 Graham Strm 01
Mangles 03 [email protected] 03 Motueka @ Woodstock 02
Little Sydney 01
Glenroy 03
Motupipi 01
Res Ck d/s Salisbury 02 [email protected] Comps 01 [email protected] 01
Wai-iti above Hiwipango 03 Roding 02
Res Ck d/s Salisbury 03
Hunters 03 [email protected] 02
Onekaka u/s Ironstone 02
Res Ck u/s Marlborough 02
Winter Ck 01
[email protected] 03
[email protected] 03
[email protected] 03
[email protected] 02
Riwaka Source 01 Onekaka u/s Ironstone 03
Waingaro 02
-2
-3
-2
-1
0
1
2
Figure 27
Axis1 Non-metric multi-dimensional scaling ordination plot showing the similarity of sites and sampling occasions based on the macroinvertebrate data. The sites are colour coded based upon the water quality classification in Section 3.2. The year when each sample was collected is indicated at the end of the site label.
4.2 REC Groupings Significant differences among REC Source of flow classes were found for the more sensitive invertebrate indices % EPT, MCI and SQMCI (Figure 28). Scores were typically lower at sites draining lowland areas than at sites draining hill country or mountains. Mountain-fed streams had higher ranges of "number of taxa" (types of macroinvertebrates), probably due to greater natural disturbance from high flow events. The single lake outlet site had scores that were equivalent to the lowland sites, but as mentioned above this is typical for lake outlet sites and not an indication of poor health.
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45 40 35 30 25 20 15 10 5 0 100 90 80 70 60 50 40 30 20 10 0 Figure 28
% EPT
T ax a
200
H = 6.7
NS
180
H = 26.6 p < 0.0005
160
140
MCI
120
100
80
60
h
m
l
lk
Source of Flow
9
H = 24.3
p < 0.0005
8
h
m
l
lk
Sourc e of Flow
H = 22.4 p < 0.0005
7
6
SQMCI
5
4
3
h
m
l
lk
Sourc e of Flow
2
h
m
l
lk
Source of Flow
Comparison of average invertebrate indices among REC Source of flow classes. h =
hill country, l = low elevation, lk = lake, m = mountain. H-statistics and p-values from
Kruskal-Wallis tests are shown for each index.
There were also strong differences in invertebrate index scores among the REC land cover classes (Figure 29). The urban and tussock sites had low taxa richness compared with the other groups of sites, while the invertebrate community in the urban and pastoral sites had a lower percentage of EPT taxa (mayflies, stoneflies and caddis flies) than the other groups of sites. The MCI and SQMCI scores indicated relatively poor health in the urban stream (Watercress Ck) and in many of the pastoral streams, while stream health in the indigenous forest, exotic forest, tussock and scrub sites was generally high.
State of Surface Water Quality in Tasman District June 2005
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45 40 35 30 25 20 15 10 5 0 100 90 80 70 60 50 40 30 20 10 0 Figure 29
% EPT
T ax a
200
H = 15.6
p < 0.01
180
H = 33.3 p < 0.0005
160
140
MCI
120
100
80
60
IF
p
ef
t
s
u
Land Cover
9
H = 35.7
p < 0.0005
8
IF
p
ef
t
s
u
Land Cover
H = 23.3 p < 0.0005
7
6
SQMCI
5
4
3
IF
p
ef
t
s
u
Land Cover
2
IF
p
ef
t
s
u
Land Cover
Comparison of average invertebrate indices among REC land cover classes. if = indigenous forest, p = pasture, ef = exotic forest, t = tussock, s = scrub, u = urban . Hstatistics and p-values from Kruskal-Wallis tests are shown for each index.
There was little clear pattern in invertebrate indices among REC stream order classes (Figure 30). The percentage of EPT taxa was lower in first order streams than in the larger streams and rivers, and some of the lowest MCI and SQMCI scores were also observed in these small streams. This effect is probably not a direct effect of stream size, but rather an indirect effect of land use, since most of the first order sites that have been sampled are in heavily developed pastoral or urban areas.
State of Surface Water Quality in Tasman District June 2005
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45 40 35 30 25 20 15 10 5 0 100 90 80 70 60 50 40 30 20 10 0 Figure 30
% EPT
Taxa
200
H = 11.7
p < 0.05
180
H = 9.4 NS
160
140
MCI
120
100
80
60
1
2
3
4
5
6
Order
9
H = 15.5
p < 0.01
8
1
2
3
4
5
6
Order
H = 7.3 NS
7
6
SQMCI
5
4
3
1
2
3
4
5
6
Order
2
1
2
3
4
5
6
Order
Comparison of average invertebrate indices among REC stream order classes. Two
first order streams join to form a second order stream, two second order streams join
to form a third order stream etc. H-statistics and p-values from Kruskal-Wallis tests
are shown for each index.
4.3 Trends in Macroinvertebrate Data
Scarsbrook et al. (2000) reported trends in macroinvertebrate communities at the National River Water Quality Network (NRWQN) sites over the period from 1989 to 1996. For the Buller Rv at Longford site they found a decrease in taxa richness (i.e. number of types of macroinvertebrates) and a decrease in the number of sensitive EPT taxa, but an increase in the MCI. At the Motueka Rv at Woodstock site they found a decrease in the percentage of individual macroinvertebrates that were either mayflies, stoneflies or caddis flies (%EPT).
5 PERIPHYTON A box plot of periphyton scores at sites throughout the Tasman District (Figure 30) shows that periphyton communities at most sites are indicative of good water quality, on the majority of sampling occasions. However, there are a number of exceptions. The Buller Rv at Lake Rotoiti outlet, Motopipi Rv at Reilly's Crossing, Reservoir Ck at Salisbury Road, Wairoa Rv at Clover Road and Watercress Ck at Dairy Factory are all notable for the large proportion of their periphyton samples that are indicative of lower water quality. There are also a number of "one-off" samples (shown as a "-" on Figure 30) that show relatively low periphyton scores, at least at the time of sampling (Figure 30). These sites are Takaka Rv at Paynes Ford, and a series of sites in the Waimea Rv catchment which were sampled during the 2001 drought (Waimea Rv at Challies Island and at Nursery, and the Wairoa Rv at WEIS Weir, Clover Rd and at its confluence with the Wai-iti Rv).
State of Surface Water Quality in Tasman District June 2005
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State of Surface Water Quality in Tasman District June 2005
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Figure 30a Box plot of periphyton scores at monitoring sites in the Tasman District (See text for explanation of scores, scores range from 110, with 10 indicating high ecosystem health).
Aorere R. @ Devils Boots Aorere R. @ La Comps Black Valley Stm below Borlase Ck. Black Valley Stm. @ L. Rotoiti Buller R. @ L. Rotoiti Glenroy @Bridge Graham @ Bridge Graham Ck. @ Kikiwa Hunters @ Weir Kaituna R. @ Solleys Rd. Kikiwa @ Kikiwa Lee R. @ Meads Br. Little Sydney @ Factory Rd Mangles R. @ Gorge Matakitaki R. @ Horse Terrace Matakitaki R. @ Murchison Matakitaki R. @ Nardoo Mot ueka @ Gorge Motuek a @ W ood ma ns Bend Motueka @ Woodstock Motueka d/s of Graham Motueka u/s Wangapeka Motupiko @ Christies Motupipi R. @ Reillys Crossing Onekaka R. @ Shambala Onekaka R. above Ironstone Ck. Reservoir Ck. @ Marlborough Cres. Reservoir Ck. @ Salisbury Rd. Riwaka R. @ Hickmotts Riwaka R. @ Northbranch source Roding R. @ Twin Bridges Sherry R. @ Blue rock Sherry u/s Cave Stanley Brook @ Barkers Takaka R. @ Harwoods Takaka R. @ Kotinga Takaka R. @ Paynes Ford Tira umea R. @ Tra ck Wai-iti R. @ Hiwipango Wai-iti R. @ Livingstone Rd. Wai-iti R. @ Pigeon Valley Waimea @ Challies Island Waimea @ Nursery Waimea R. @ Appleby Br. Waingaro R. @ Hanging Rock Waiora @ WEIS Weir Wairoa @ Clover Road Wairoa @ Wai-iti confluence Wairoa R. @ Irvines Wairoa R. @ Pig Valley Waiwhero [email protected] Wangapeka @ Walters Pk Wangapeka u/s Dart Watercress Ck. @ Dairy Factory Winter Creek @ culvert
12 10 8 6 4 2 0
Periphyton Score
Sites with frequently low periphyton scores are also evident in Figure 31, which provides a simple spatial overview of the way the periphyton indicator behaves over the Tasman District. The majority of sites that had a high proportion of their periphyton scores below a score of 8 also showed high levels of exceedance of guidelines for nutrient concentrations (Figures 7-10). These were mainly lowland streams, draining agricultural land. The exceptions to this were the Buller Rv at Lake Rotoiti site and the Wairoa Rv at Irvines site. The Buller Rv at Lake site probably owes its low periphyton scores to a highly stable flow regime, typical of lake outlets, allowing lower-scoring filamentous algae to establish. However, the reason why the Wairoa Rv at Irvines site should score so lowly, in the absence of high nutrient loads, is not obvious.
Figure 31 Proportion of samples for which the periphyton community indicator scores from each site that did, or did not, exceed a score of 8. (A score of 10 is the highest possible, indicating a healthy stream.)
State of Surface Water Quality in Tasman District June 2005
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Case Study ­ Lake Rotoiti Sampling of Lake Rotoiti undertaken in 1999 (Smith, 1999) indicated that the lake is fully oxygenated and has low levels of nutrients, as would be expected for a lake that is virtually unaffected by human activities. Comparing these results with earlier investigations in 1976, 1990 and 1992-94 indicate that the quality of the lake environment has not changed significantly in the past 25 years. Monitoring Black Valley Stm, the only waterway with any potential to affect water quality of the lake, has shown good water quality over the past five years. Nutrient concentrations in the stream were almost always within guidelines and the waterway was always suitable for contact recreation. Macroinvertebrate health was also very good. 6 DISCUSSION OF THE STATE OF TASMAN'S SURFACE WATER QUALITY 6.1 General The lower reaches of the main rivers throughout the Tasman District are in relatively good condition compared with many of the other large rivers around the country (Larned et al., 2004). The relatively high proportion of indigenous forest in the catchments of large Tasman rivers means that inputs of pollutants from developed tributaries joining the river in the middle and lower reaches are diluted by a large volume of high quality water from upstream. Macroinvertebrate communities in the lower reaches of the main rivers are indicative of clean water or mild pollution (Boothroyd and Stark, 2000). High water temperatures in the summer, rather than chemical pollutants, may be responsible for the reduction in river health scores in the lower reaches of the main rivers (Young et al. in press). Streams and rivers draining the higher altitude and undeveloped areas of the Tasman District have excellent water quality and support a diverse range of macroinvertebrates. Periphyton accumulation at these sites is minimal and is dominated by diatoms. Throughout the Tasman District, small streams draining developed land (agriculture, urban, horticulture) are typically in poor condition, with low water clarity and high concentrations of nutrients and faecal indicator bacteria. In a few extreme situations, dissolved oxygen levels are low enough to harm aquatic life. Small streams draining developed land have macroinvertebrate communities indicative of moderate to severe pollution (Boothroyd and Stark, 2000). Periphyton accumulation in some of these streams is excessive and likely to cause nuisance to those people recreating in these areas. Given the poor state of many small streams draining developed areas, restoration efforts should focus on trying to improve the quality of these systems. If improvements can be made, this will also lead to small cumulative improvements in the quality of the main rivers. June 2005
6.2 Pressure, State and Response in Relation to Various Resource Use Activities This section highlights the monitoring and regulation issues relating to the more significant environmental pressures in Tasman District. For some pressures not enough data is available to make comment. This lack of data stems in part from the fact that not all pressures, for example fruit-growing, are represented in the Surface Water Quality Monitoring Programme. 6.2.1 Sewage Discharges from Municipal Sewerage Systems Pressure Raw sewage or poorly treated sewage discharges can contain high concentrations of bacteria that may cause disease in humans and livestock, and ammonia, which is toxic to aquatic life. Ammonia and other contaminants in sewage effluent can reduce the oxygen in the receiving water and cause suffocation of organisms living in this environment. Discharges of raw sewage are of particularly high threat to human health and may cause ecological damage due to high concentrations of ammonia. The sewage from all towns in Tasman District is treated with plants at the following locations: Collingwood, Takaka, Upper Takaka, Motueka (also services Riwaka to Kaiteriteri), Tapawera, Murchison, St Arnaud and the regional sewage facility at Bell Island (serves Wakefield, Brightwater, Hope, Mapua, Richmond and a large part of Nelson). These treatment plants generally employ oxidation ponds, the performance of which may be affected by variable effluent loading rates. Such loadings increase dramatically over the summer tourist seasons at many of these plants. Raw sewage overflows from pump stations occur periodically in parts of the District, typically where stormwater has not been separated or not successfully separated (possibly through ingress) and heavy rainfall events producing more stormwater than the reticulation system can cope with. State "State of the Environment" and compliance monitoring programmes have indicated that there are large variations in the quality of effluent (sometimes well above guideline or compliance limits) and that this consequently has large effects on the quality of receiving water. Faecal bacteria concentrations at the mouth of the Aorere River downstream of the Collingwood sewage treatment plant and dairy farm effluent discharge receiving waters are regularly above national stock drinking water guidelines. Localised drains and small waterways in areas such as Little Kaiteriteri and Pohara have at times been highly contaminated with faecal material from the discharge of untreated or poorly treated sewage. June 2005
Response Sewage Treatment System Upgrades: Upgrades are either in process or imminent at Tapawera, Murchison, Motueka, Takaka and Collingwood. The Collingwood sewage treatment plant, which currently consists of an oxidation pond and artificial wetlands, is due to have a UV treatment system added on in mid-2005. Sewerage Reticulation Projects: Several townships have had reticulated sewerage installed in the last five years including St Arnaud, Richmond (Hill Street), Motueka, Tapu BayKaiteriteri and Takaka/ Pohara. Stormwater-Sewer Separations: A programme of separation of stormwater and upsizing of sewerage reticulation systems is ongoing. Monitoring: Tasman District Council contracts MWH Ltd to monitor all sewage discharges it is responsible for. This monitoring occurs at a frequency of six samples per year and quantifies flow and several water quality parameters. TDC compliance officers audit these discharges annually and more often when the facilities are non-compliant. Septage (septic tank discharges) Pressure Potential environmental effects of discharges from septic tanks are similar to that of sewage (see above) but adverse effects are more likely to manifest where septic tanks are concentrated near waterways, soil permeability in the infiltration field is low (e.g. clay soils) or very high (e.g. sand/gravel) and/or they are poorly maintained. State Very little information is available on the effects of septage on waterways. There are several examples where national guidelines for contact recreation have not been met due to septage discharges to water. However, most of these investigations are as a result of complaints or from sanitary surveys that follow-up when a bathing area fails to meet guidelines. Response Compliance of such discharges is not routinely monitored by Council but is responded to as a result of complaints from the public or when identified through other monitoring acitivities. However, a survey of groundwater in Golden Bay in areas where septic tanks are common was undertaken in January 2005. Sixteen out of a total of 23 bores sampled had detectable E. coli, with a mean of 5.1 E. coli/100ml. Five results were in the range 100-270 E. coli/100ml. Generally, these concentrations are expected to be further reduced by natural die-off on the passage to waterways and therefore not considered a likely threat to surface water, although serious if consumed from the bore supply. In some areas where septage is known to be an issue "Warrants of Fitness" for the individual treatment systems could be issued on a regular basis, as happens in Marlborough. June 2005
Discharges in excess of 2 m3/day, or those in defined sensitive receiving environments, require resource consent and are monitored annually. Any discharge, whether permitted or consented, found to be non-complying, is liable to some form of enforcement, and in most cases, the issue of an abatement notice. 6.2.2 Discharges from Farms and Fertiliser Operations Pressure Untreated or poorly treated farm dairy effluent contains high concentrations of contaminants that are either toxic (such as ammonia), or potentially disease causing. Fertiliser run-off can cause nutrient enrichment and consequent prolific growth of aquatic plants and algae. The visual clarity of the water is often reduced, which affects aesthetic quality and the ability of fish to locate prey. Beds of waterways can become covered with manure solids. The small to medium sized creeks and streams (first, second and third order) are the most vulnerable to pressures from dairy farm activities. There are currently 33 dairy farms that discharge treated effluent directly to water in the District. A further six that currently discharge to water are planning to discharge to land, or have applications for discharge to water pending. High cattle stocking densities have been correlated in some areas with poor water quality. Stocking rates in the District are variable, with a range from 1-6.8 cows per hectare. The following is a breakdown of stock per locality: Rockville: 1.5-3.5 cows/ha, Pakawau 1.5-4.0 cows/ha, Motupipi-Wainui 2-4 cows/ha, Korere 1-2.5 cows/ha and Waimea 2-6.8 cows/ha. However, Nottage (2000) found for streams in the Aorere catchment that there was a poor correlation between these factors. Fonterra and the Ministry for the Environment have recently published a report on the progress on these issues on a region-by-region basis. The performance of farms in Tasman District compared to the rest of the country was generally below average, particularly for employing nutrient budgets, percentage of farms with unbridged regular crossings and effluent discharges. However, Tasman District was slightly above average for restricting of stock access to waterways. State The effects of agricultural development on water quality and stream health has become widely recognised throughout New Zealand over the last two decades (Wilcock, 1986; Quinn et al., 1997; Harding et al., 1999; Quinn, 2000; Parkyn and Wilcock, 2004). The effects of urbanisation on water quality and stream health are also well known (Suren, 2000; Suren and Elliott, 2004). The main threats to water quality and stream health in the Tasman District relate to the recent and continuing intensification of agriculture in the District, and to a lesser extent the expansion of residential development. The effects of intensive horticulture on streams is not well known. The Kikiwa suite of sites (Hunter Ck, Kikiwa and Graham Stm) in the upper Motupiko River Catchment provides a useful comparison of land use effects, as each site is almost completely dominated by either sheep and beef, exotic forestry or native forest, while having very similar geology, source of flow, network position and valley landform. Kikiwa Creek with sheep and beef has significantly higher E. coli and nutrient concentrations compared to the other two land uses (median: 300 E. coli/100ml compared to a median of 15 and 10 for Graham and Hunter Creeks June 2005
respectively). Motupipi River and Sherry River at Blue Rock, whose catchment is dominated by dairy farming, also has high E. coli concentrations (median: 375 and 400 respectively). The reference site on the Sherry River showed a median of only 35 E. coli/100ml). The Kaituna and Onekaka Rivers showed reasonably low median E. coli concentration (100 and 177.5 respectively) but the proportion of the catchment in dairy farming was significantly less. The recreational water quality monitoring site on the Takaka River at Paynes Ford showed two significant exceedances of guidelines in early 2005 after a particularly wet period. These results could be due to run-off of farm effluent, as most of the farms up the Takaka valley discharge to land and do not have holding capacity to avoid this during wet periods. The removal of riparian vegetation and resultant loss of shading from many streams has caused water temperatures to be elevated to the point where many aquatic organisms die. Careful management will be required to ensure that water quality and stream health does not decline as a result of these changes in the District. Response Most farmers now use commercial fertiliser applicators to spread phosphorus and lime and almost all these applicators have "Spreadmark" certification that dictates a number of environmental controls. Nitrogen fertilisers such as ammonia-urea are spread by farmers themselves, as the timing of the applications is more critical. In general, there has been little uptake by farmers for creating wetlands for nutrient or sediment run-off retention. TDC has encouraged and promoted the formation of Landcare Groups with an interest in environmental quality and worked with them to achieve their environmental goals. One of the most successful Stream Care groups in the District is operating in Murchison. This group has protected creeks near the township with fencing, removing weeds and planting. The use of the Stream Health Monitoring and Assessment Kit (Biggs et al., 1998) should be encouraged for the monitoring of impacts on water quality, particularly from dairy farming activity. Discharges of dairy farm effluent to land are audited against the permitted activity rules (Chapter 36.1.3 of the proposed Tasman Resource Management Plan) once every five years. This is programmed to change to biennial monitoring, with a report on findings published at the completion of each two yearly cycle. All consented dairy farm effluent discharges to water are inspected annually and are sampled for Biological Oxygen Demand (the potential for the waste to reduce the dissolved oxygen in the receiving water) and suspended solids. It is recognised that such discharges should be sampled in addition for faecal coliforms and ammonia, as these are the parameters most likely to compromise values in the downstream catchment e.g. bathing beaches, shellfish farming and aquatic ecology. Resource consent conditions should also require additional monitoring (two to three times per year unless there has been a high level of compliance. Future consent will require compliance limits applied to the receiving water. Stock crossings and the presence of cattle in creeks have been shown to cause a major loading of disease-causing organisms to waterways (Davies-Colley et al., 2004). TDC has recently set up an intensive sampling programme of waterways in farmland to determine the locations and activities that cause major faecal bacteria loads to the coast, affecting shellfish June 2005
farmers and gatherers. Following on from this study corrective actions have been identified. Advice and promotion of bridging or culverting waterways has been given by Council and Fish and Game on these issues and many farmers have taken this positive action, particularly in the Sherry River catchment. An inventory of major crossings has been undertaken by Council staff. Many feed pads and stand-off pads located close to waterways have been re-sited and associated effluent better managed. A comprehensive survey of waterways on farms has recently been undertaken in Golden Bay to determine the major sources of faecal contamination to the marine environment. The Dairying and Clean Streams Accord was signed by Fonterra Co-operative Group, Ministry for the Environment, Ministry of Agriculture and Forestry and Local Government New Zealand in May 2003. This has led to stronger commitments to address these issues. A regional action plan relating to the Accord is close to being ratified. 6.2.3 Stream Habitat Modification Pressure Removing riparian vegetation, installing in-stream ponds and rock armouring of the stream bed can lead to high water temperatures, particularly in small waterways. Even after stream replanting, streams may take years to achieve satisfactory temperatures due to the time it takes for trees to become large enough to produce shade. State Widespread and frequent exceedance of temperature criteria for protecting ecosystem health was observed in the Motueka catchment (see Figure 20) and Reservoir Creek. Response In recent years farmers have put considerable effort into stabilising streams, not only to preserve farmland, but also for reasons of stream habitat and controlling stream temperature. However, streams on sheep and beef farms tend not to be fenced or stabilised. The TDC subsidy for fencing and stability works is always fully subscribed. TDC is looking at revising its Engineering Standards and Policies to include stream redesigns that will maintain more natural water temperatures. 6.2.4 Damming and Taking Water Pressure Damming water can lead to higher water temperatures if the discharge from the dam is from the surface or low dissolved oxygen if the discharge is from the base of the dam. Taking a large percentage of the flow in a waterway can adversely affect water quality by reducing the amount of available dilution for discharges to water and contributes to excessive water temperatures during warm summer periods. June 2005
State Limited information exists on the effects of large water takes or cumulative effects of multiple takes on water quality. It appears that there are few situations where there are significant discharges to water where such takes occur (excluding the Moutere Ditch). The temperature of water released from the Cobb dam is on average 4oC higher in summer than neighbouring catchments (Young et al 2000). Response Limits are placed on how much water can be taken from particular catchments via the proposed Tasman Resource Management Plan. These limits seek to preserve sufficient flows to avoid adverse environmental effects. Most consented water takes are required to fit water meters and record the amount of water used. This meter data is monitored by Council through the irrigation season and audited on a regular basis, with sporadic site inspections occurring in addition. Rationing of water takes is instigated from time to time during periods of drought. The taking of water for stock drinking water and water takes up to 5m3/day are permitted, although subject to conditions that seek to avoid adverse environmental impacts resulting from low flows. 6.2.5 Discharges of Sediment from Earthworks and Stockpiling of Material Pressure Discharge of sediment with stormwater run-off from earthworks such as subdivision development, roading and pasture redevelopment can cause: (a) reduction in water quality, as indicated by reduced clarity; (b) smothering of aquatic organisms by sedimentation of the stream bed. Such earthworks activity is particularly apparent in the Moutere Hills, St Arnaud and in Reservoir Creek catchment. Major quarries include a dolomite quarry in Aorere Valley, near Collingwood, several hard rock quarries up the Wairoa and Lee river valleys. Alluvial gold mining operations, such as in the Matakitaki River catchment, have considerable potential to discharge fine sediment. Although sediment loading to waterways is often naturally high during and after rainfall, the settling velocity is low due to high horizontal river velocity. Comparatively low sediment deposition occurs compared with high sediment discharges from various activities at times of low flow. As has been described earlier, small streams are more vulnerable but small spring-fed streams are even more vulnerable, due to infrequent high-flow events that would flush out the sediment. State Water clarity of the Takaka River downstream of the Cobb powerhouse was often poor in 1999 and little information has been collected since then. The level of fine sediment in the bed of the Onekaka River downstream of the dam has been high on occasion. "State of the Environment" monitoring results from the Matakitaki River show considerable amount of fine, pale grey-coloured sediment within the bed matrix and banks. Macroinvertebrate June 2005
results are variable, with spring 2001 and spring 2003 showing a marked reduction in species richness and total number of mayflies, stoneflies and caddis flies at the Murchison site compared to the Horse Terrace site upstream of most of the mining activity. No significant difference was found between all three sites on the Matakitaki River for the 2002 sample set. It is not known when the main mining activity occurred in this catchment and hence whether this poor condition can be correlated to the mining activity. A small partly spring-fed creek in Murchison has recently been found to contain a heavy fine sediment load, most likely from a relatively small yard development that did not protect sediment run-off during a storm event. This situation is likely to affect trout spawning in this creek. A heavy sediment load is also found in the Motupipi River, which is also springfed. A report on the effects of gravel extraction from the Wairoa River showed significant adverse effects on macroinvertebrate species richness but only minor effects on total macroinvertebrate abundance (Kelly et al., 2005). It could be that substrate size is the major factor governing invertebrate species richness, as this was the main physical habitat feature that changed downstream of gravel harvesting areas. Response Most earthworks work parallel to the contours, which reduces the sediment run-off considerably compared to working up and down slope. The main river channels upstream and downstream of river-based gravel extraction operations, such as for river maintenance purposes, are generally inspected monthly, after water has been bank to bank as a result of storm event, or as necessary. A more thorough site inspection is carried out as part of every resource consent application and upon completion of works approved by the consent. This includes a site visit with the consent holder prior to the exercising of consent. Council's Asset Engineer (Rivers) and Resource Scientist (Rivers) also comment on any gravel extraction consents received. Inspections of quarries and mining is generally carried out annually, however, some large quarries have not been monitored for some time now. 6.2.6 Forestry Pressure Forest harvest operations have the potential to detrimentally affect the quality of adjacent water bodies with discharges of fine sediment and woody debris. If a riparian buffer zone is not left (i.e. trees are harvested right up to stream bank), harvest operations have been shown to change the amounts and characteristics of woody debris in streams and increase channel bank disturbance, i.e. erosion. Additional woody debris enters the stream channel from thinning operations and windthrow. Large amounts of woody debris, particularly finer particles such as pine needles, in water bodies can impact their water quality. However, removal of most or all wood from a stream channel can raise water temperatures to levels that can be stressful to some aquatic animals (Baillie and Cummins, 1998) and reduce the available habitat. A relatively large proportion of the Tasman District is covered by exotic forest (particularly in the Wairoa, Lee and Motueka catchments). Other forestry activities can impact on water June 2005
quality and stream health (Harding et al., 2000; Fahey et al., 2004). Land preparation and forest establishment produced about 7.5% of the background sediment production with roading making up about 0.75% of background production on an annual basis (Fahey et al 2004). Nevertheless, large inputs of sediment discharged to waterways after rainfall events may have longer lasting effects in the coastal and marine environment. Pinus radiata forest tends to produce lower catchment yield (rainfall run-off to waterways) as a result of rainfall interception and evapotransporation than other forest or pasture. State Data reviewed here from sites draining catchments dominated by mature exotic forest generally had water quality and stream health that was equivalent to that in native forest. Graynoth (1992) suggested that reduced stream flows on the Moutere gravels caused by mature Pinus radiata may have more serious impact than short-term effects from sediment discharges. In the larger catchments on the West Bank of the Motueka River where production forestry only covers about 20% of the catchment, there are only small effects due to harvesting operations (Hewitt, 2002). However, in the smaller Kaiteri Forest where the catchments are much smaller, and percentage forest cover much greater, harvesting effects are much greater. In the West Bank Forest, where catchment areas range between 8 and 26 km2, sediment yields vary from 20 t/km2/year pre harvest, to 150 t/km2/year `during' and postharvest. Unlike in the Kaiteri catchments, there was no measurable difference in sedimentconcentration/flow rate relationships from `during' to `post harvest' in the West Bank catchments. In the Kaiteri Forest, sediment yields ranged from 40 t/km2/year pre harvest, to 378 t/km2/year at the peak of harvesting. Bedload was recorded in the Kaiteri catchment at an average rate of 27% of total sediment load from that catchment. Response In harvesting operations, the forestry industry makes extensive use of aerial hauler systems that lead to considerably less sediment run-off compared to a decade or more ago when skidders were used to drag logs over the land surface and through streams. Maintaining riparian buffer strips was introduced as general practice by the major forestry companies in the late 1990s. The larger forestry companies in this District follow comprehensive Environmental Management Systems that have been developed under ISO 14000. These systems require that if any issues arise from their operation, including any complaints from the public, irrespective of the requirements of the resource consent, an incident investigation be undertaken and communication with TDC and sometimes other stakeholders. General inspections of forest harvesting or roading operations by Council is undertaken as required and auditing of forestry companies' operations are carried out by Council and other independent auditors. A TDC officer is represented on the Weyerhaeuser Environmental Improvement Committee, which assists greatly in communicating objectives and ideas for environmental improvement between the organisations. TDC planning rules now restrict the area of a title that can be planted in new forest in Moutere gravel terrain to no more than 20% to ensure higher water yields are maintained. June 2005
6.2.7 Industries Storing or Using Hazardous Chemicals Pressure Discharges of contaminants to surface water (often via groundwater) from landfills, timber treatment plants, petroleum installations and trade waste from many types of industries have the potential to cause considerable environmental damage through toxicity of the material and bioaccumulation. Sixteen closed and two open Council-run landfills exist in the District, with the Eve's Valley landfill being by far the largest. The toxin 1080 (sodium monofluoroacetate), which is used widely throughout the District to limit bovine tuberculosis (Tb) spread and for nature conservation purposes, and pesticides from horticultural operations have the potential to get into waterways and cause adverse effects, particularly from discharges resulting from poor application practices and the rinsing of used pesticide containers. Organo-chlorine pesticides, such as dieldrin, aldrin, DDT, dioxins and furans, are particularly long-lived in the environment as well as being very toxic in high enough concentrations. Lead arsenic was used as an insecticide in sheep dips and horticultural crops, and these harmful residues remain in the soil and then could be mobilised through erosion and discharged into waterways. Discharge of household chemicals to waterways has the potential for serious adverse effects. These include the large scale industries of Dynea and Nelson Pine Industries to car wreckers, transport yards and truck washes, vehicle workshops, concrete and cement plants and spray-painters. Most of the smaller industrial premises in lower Richmond (including the transfer station) were found to discharge untreated stormwater into waterways. Poor onsite management of potential spills and inappropriate storage of hazardous substances is also likely to contribute to the risk of contaminants entering these water bodies. State A survey of discharge to stormwater from the Richmond industrial area was carried out in 1998 and 2004 (Easton, 2005). Moderate to high concentrations of heavy metals and poly aromatic hydrocarbon contaminants were found in waterways receiving run-off from industrial land in Richmond. By comparison, the study showed low concentrations in urban and rural catchments near Richmond. Limited monitoring of waters receiving landfill leachate has indicated adverse effects only in small waterways. Sediments of waterways near the Richmond landfill were found to have high concentrations of heavy metals. It is not known whether pesticides are found in waterways and if so, what effect they may be having. Only two monitoring sites in the current "State of the Environment" programme are on waterways where the dominant land use of the catchment is horticulture (Little Sydney and Riwaka) and no pesticides are sampled. Ministry for the Environment (1999) conducted a survey of shellfish and sediment in estuarine sites throughout New Zealand in 1998, including two sites on the Moutere Inlet, and found very low organo-chlorine concentrations. Sampling by the Animal Health Board and Department of Conservation carried out before and after a 1080 operation shows no significant adverse effects on water quality or aquatic ecology (Broome et al, 2005 and from numerous compliance monitoring reports supplied to TDC). June 2005
In 2003 a pesticide was dumped to stormwater in the urban area of Richmond, which then flowed into Jimmy Lee Creek and caused considerable eel deaths. Response Landfills: All of the 16 closed Council-run landfills in the District are inspected annually and samples of leachate are collected if leachate intercepts the surface. Groundwater sampling has only been carried out at three of these sites. At one of these sites contaminant concentrations were found to be elevated and remedial measures (including capping and armouring) were undertaken but no further sampling has been carried out to confirm the action was effective. Management Plans for all closed landfills should be produced to ensure any adverse effects of future management are taken care of. Monitoring of the new Stage 2 of Eve's Valley landfill has begun after a two year delay. Timber Treatment Sites: Of the five timber treatment sites in the District, only two are monitored (on an annual basis). The largest site, near Motupiko beside the Motueka River, has recently upgraded the site's stormwater management. In response to the recent (March 2005) flood event, work has been done on the stopbanks to protect this site and a further site upgrade to ensure the timber treatment chemicals are contained. Upgrades are being planned for the plant located near the Little Sydney Stream near Riwaka. Another large operation in Richmond was prosecuted by Council in 2004 for discharges of tributyl tin to Vercoes Drain, which flows into the Waimea Estuary. Petroleum Installations: Groundwater contamination is known to occur from historic service stations in two locations and these are being monitored. The 29 operating service stations and large fuel facilities in the District have been required to upgrade to meet the Council's hazardous facility rules. Currently, there are only a few sites yet to comply with these rules. Trade Waste: No Trade Waste Bylaw exists in Tasman. However, an Australia-New Zealand Standard is being developed that may be used in Tasman in the future. Potential contaminants from trade waste should be monitored regularly, such as the leachate being reticulated to Bell Island wastewater treatment plant from Eve's Valley landfill. 1080: Many methods to reduce potential adverse effects from 1080 applications are employed, such as reducing the concentration of 1080 in pellets used in applications and requiring global positioning systems to be fitted to all aircraft to control the application of 1080 and reduce the amount deposited in waterways. Water quality sampling occurs after most aerial application operations. It has been identified that management of many industrial discharges needs to be improved. Few industries have resource consent and few are monitored adequately, and then mostly in response to complaints. Hazardous facilities are monitored annually as a minimum. Those that are required to are presently going through resource consent process. A Motueka industry survey has been undertaken and remedial action taken where issues were identified. A new survey for Richmond's industrial sites is planned within the next year. Dynea and Nelson Pine Industries have facilities for collecting and treating stormwater and process water from their sites. The limited amount of monitoring to date shows contamination of estuarine sediments is not significant around these two sites. June 2005
Council's Environmental Education Officer has led an effective campaign to educate the community as to the negative effects of tipping chemicals and disposing of car-wash effluent to stormwater. Yellow fish are painted on the majority of stormwater grates in major urban areas in the District to remind people of where the drain ends up. 6.2.8 Orcharding Pressure Apple dump wastewater contains mostly sediment, but there can be low concentrations of pesticides washed off the apple skins and traces of chlorine (15-50 ppm), which is sometimes added to the dump water to inhibit stem rot. Combined with a rate of discharge in the range of 5-20 m3/week, there is potential to cause environmental problems if not done properly. It is estimated that over 7,000 m3 of apple dump water is discharged to land throughout Tasman District over the 12­16 weeks duration of the packing season (Milson, April 2004). Between 2001 and 2004 the number of packing houses decreased from 55 to 36. However, the total area of orcharding land had not declined significantly. State It appears that no waterways have been sampled for chemical residue where orchards are the dominant land use in the catchment. Response Based on a study undertaken by the TDC in 1993, it was recommended that the apple dump wastewater should be disposed to land (where sunlight and natural soil micro-organisms would be expected to break down the contaminants) rather than into waterway where the toxicity of contaminants could cause problems to aquatic life (Milson, April,2004). Rules controlling apple dump wastewater disposal were put in place shortly after. Pesticides used currently include Diphenylamine, Dithiocarbamates, Dodine, and Chlorpyrifos. Azinphos­methyl, Carbaryl, Gusathion Diazinon, and Atrazine are either banned, being phased out or no longer in use due to their high toxicity in aquatic ecosystems. Given this development, free chlorine is now the contaminant of most concern. A number of orchards visited were adopting biological methods for pest control, using pheromone strips at key times of the apple growth cycle. A 14 day minimum withholding period between the final spray application and picking the apples seems standard, and this should help reduce the level of toxic chemicals in the spent apple dump water. Spray diaries are closely monitored by Pipfruit New Zealand (PNZ) and the Integrated Fruit Production (IFP) system. Apples are routinely tested for chemical residues as part of these, ENZA, AgriSure and other export programmes. In addition to annual compliance audits, detailed compliance assessments were undertaken by TDC in 2001 and 2004. The latter follow-up also included a compliance assessment of discharges of smaller volumes of effluent from the packing house drench plants which require disposal. One of the drenches in common use is toxic and these residues must also be disposed to land, well away from any waterways. However, this drench is likely to be phased out in the next few years. Those orchards who were not complying (<10% of all visited) were followed up appropriately. June 2005
Through TDC's interaction with orchard owners or managers there was a high level of awareness and increased compliance of the TRMP rules relating to the disposal of spent water from the apple dumps. Also, more attention appears to be being given to apple spray programmes than in the past to improve the efficacy of the sprays and to reduce their usage. The TRMP rules and industry's own best practice guidelines appear to be effective at controlling environmental effects. In general, the standard of spray sheds was very high, with the requirements of location (not prone to flooding), spill containment (bunding), security, Hazchem signage, ventilation and personal protective equipment (ppe) being met. Fuel storage was not to such a high standard, with many tanks being unbunded, the drain pipes on many that are bunded being in an open position (making the bund ineffective), and many with diesel spills on the ground. A number of bunds were full of water (also making the bund ineffective) and/or rubbish and required cleaning out. The Hazardous Substances and New Organisms (HSNO) regulations which came into force on 1 April 2004 (hazardous substances) and 1 July 2004 (pesticides) create new requirements for the storage and handling of these materials, in addition to Council requirements, and all landowners will need to ensure they comply with the new regulations. 6.2.9 Winery Waste Disposal Pressure The three main discharges associated with winery operations are: (a) wash water from rinsing bottles and barrels and washing floors and tanks; (b) domestic wastewater from staff or cafй ablution facilities; (c) leachate from composting marc and other organic solids. The sugar content of winery waste causes the washwater and leachate to have a high biochemical oxygen demand, which has the potential to reduce dissolved oxygen concentrations in waterways to a level that could kill aquatic organisms. The level of nutrients, suspended solids and the pH of the discharges of winery wastes may also have adverse effects on the receiving environment. Winery washwater is either drained directly to land, or run into ponds for the Irrigation water supply. In one case the water is stored and removed by a liquid waste contractor. Most solid wastes are composted and discharged to land or fed to stock. The area in vineyards increased in the Tasman District from 256 hectares in 2001 to 454 hectares in 2004 but the number of processing facilities reduced by nearly half (Milson, May 2004). State It appears that no waterways have been sampled where vineyards are the dominant land use in the catchment. Response Compliance assessments were carried out in 2001 and 2004, both showing a high standard of compliance and there was good awareness within the winemaking community of their June 2005
obligations for waste management. Four of the composting operations require some improvements to ensure that leachate is more adequately controlled. The wine industry has developed their own standards (SWNZ ­ Sustainable Winegrowing NZ) to help minimise the environmental impact of grape growing and processing. 6.2.10 Other Fruit Growing Pressure Berry fruit waste has high BOD and colour. State No systematic monitoring of berry fruit farms has been undertaken. Response Occasional inspections of some berry fruit farms. 6.2.11 Market Gardening Pressure Wastewater, particularly from hydroponic greenhouse discharges and leachate from composting operations contains high concentrations of nutrients. Intensive water and fertiliser use occurs, enabling many crop rotations to occur each year. State It appears that no waterways have been sampled where market gardening is the dominant land use in the catchment. Many market garden operations regularly use chicken manure as a fertiliser source. Response No monitoring is carried out for hydroponic greenhouse discharges, although it is anticipated to occur as part of a nitrate management review in the Waimea plains. 6.2.12 Fish Farms An independent consultant monitors the two farms monthly or bi-monthly, with TDC auditing annually. Occasional minor non-compliance has been recorded with respect to water clarity. June 2005
6.2.13 Miscellaneous Discharges Pressure Discharges of sawdust, lawn-clippings and other organic waste can smother the beds of waterways and lower dissolved oxygen. State Lawn clippings disposed of beside a tributary of Reservoir Creek were found to be the cause of low dissolved oxygen and poor macroinvertebrate condition in this tributary. Response Education and enforcement measures to be implemented as appropriate with respect to discharges to waterways. 6.3 Other Responses Integrated Catchment Management In the Motueka catchment considerable research is being put into resource management issues over a range of scientific disciplines. The Motueka Integrated Catchment Management (ICM) seeks to create integration amongst scientific disciplines, between communities, scientists and environmental managers within the catchment boundary. A report summarising the current state of knowledge in the Motueka catchment was produced in 2003 (Basher, 2003; this can be downloaded from the following website: http://icm.landcareresearch.co.nz/Library/project_documents/ICM%20Report.pdf ). There have been a number of water quality investigations, many of which have been discussed in this report. In addition, the following projects have been completed or ongoing: (a) riparian vegetation assessment for the Sherry River; (b) assessments of various native plants at stabilising stream banks, culminating with workshops on the topic; (c) investigations into the riverine effects on coastal habitats in Tasman Bay, including nutrients and sediment; (d) developing an environment for social and cultural learning, collaborative research, and partnerships to improve knowledge uptake. Water Conservation Orders Water Conservation Orders have been designated for large parts of the Buller and Motueka Catchments. These designations are set up to protect waters of outstanding importance for amenity or intrinsic values. Fish and Game applied for both Water Conservation Orders to protect the trout fishery, wild and scenic character. June 2005
7 RECOMMENDATIONS
7.1 Changes to the Monitoring Programme
While recognising the value of a long-term data set that is based on consistent high quality data from the same sites using the same parameters and similar sampling intervals, there is little value in maintaining the status quo if there are good reasons to make changes to a monitoring programme.
7.1.1
Add more sites on small streams to the programme. Small (first and second order) streams are highly under-represented compared to the percentage of these streams in the District. Small streams are the most vulnerable to pollution. Any new sites chosen should cover both "reference" sites draining areas that are largely undisturbed and "impact" sites that are currently facing pressure, or are likely to in the near future. Several sites on small streams were added in late 2004.
7.1.2 Rationalisation to enable adding sites as above
(a) Remove some sites on larger waterways in order to add sites on small streams. Sites that are candidates for being dropped or moved are: Aorere at Devil's Boots, Wai-iti at Pigeon Valley, Wairoa at Irvines. Sites dropped in the last year: Buller at Lake, Glenroy at Bridge, Matakitaki River at Nardoo, Matakitaki at Horse Terrace, Motueka d/s Graham. Reasons for dropping these sites are explained in a report on surface water quality for the upper Buller catchment (James, 2004).
(b) Cease collecting data from NRWQN sites other than faecal indicator bacteria.
(c) Cease collecting samples for Total nitrogen and total phosphorus analysis except at downstream sites of the large river catchments throughout the District. Cease sampling for Total, Fixed and Volatile suspended solids unless for targeted impact investigations to identify the likely causes of poor water clarity or high turbidity.
7.1.3
Collect macroinvertebrate samples biannually (once in spring and once in autumn) for the next two years and then move to autumn thereafter. This is due to unpredictable weather and flow conditions in spring often upsetting sampling plans and worst-case stream health will generally occur in late summer as a result of low flows, algae accumulation and warm water temperatures. Sampling in both spring and late summer should be undertaken for at least two years to identify the likely seasonal changes in macroinvertebrate community composition at the sites.
7.1.4
Determine the behaviour of contaminant load semi-continuously over a few flood events upstream of sensitive receiving environments e.g. faecal bacteria delivered from the Aorere River to Golden Bay. In this case, the load delivered during large floods will probably be much greater than that delivered over a much longer time period at low flow. Therefore, automated flow-weighted samplers that would sample water throughout floods would be required to calculate an accurate load to the Bay. This kind of sampling is expensive and logistically difficult as staff have to be on standby ready for a flood event. This work is being undertaken in the Motueka River catchment as part of ICM research and has been undertaken in the Aorere River at Devil's Boots.
7.1.5 Increase sampling interval. To be able to detect trends in water quality in the District in less than 10 years from now, more frequent sampling is required. This increased frequency
June 2005
could be carried out at a selection of sites to limit increased costs. This is a medium priority but will add significantly to the cost.
7.1.6
Undertake semi-continuous sampling for dissolved oxygen, pH and temperature at all sites on a rotational basis. These parameters can vary considerably on a 24 hour cycle, meaning that discrete samples should be collected at the same time of day at all sites to be able to compare results with any real meaning. Obviously, this is not possible unless deploying field meters that log data. TDC has two of these and can hire or loan one or two more, enabling efficient and cost-effective coverage of sites. This is a high priority with little extra cost.
7.1.7
Install turbidity and conductivity probes for continuous sampling at key hydrometric stations. Once a correlation is established between these parameters and contaminants such as faecal bacteria and nutrients, the total loading can be established at a range of flows at relatively low cost. These could be established at downstream sites of the large river catchments throughout the District (the last three sites listed above). Low-medium priority.
7.1.8
Increase targeted impact investigations to be able to determine the effects of specific activities within a land use. Part of the annual budget could be dedicated to this type of monitoring to be able to respond to new land use pressures occurring in different areas. It is also a case of moving through the list of priorities ranked on environmental risk. Priorities for such investigations include:
(a) determining what, and where are the activities within the dairy farming land use in Tasman District that generate the highest faecal bacteria loads. Such investigations have begun in coastal western Golden Bay;
(b) what are the causes of the high nutrient load to the Motupipi River? This could potentially involve groundwater monitoring, given that this waterway is fed largely by groundwater;
(c) determining the effects of sewage or septage on waterways from new cluster housing subdivisions such as those proposed in the Moutere. This has implications for planning rules for the Rural 3 Zone.
7.2 Information Management
7.2.1 An inventory of environmental information should be set up using a Web-based, spatially referenced system. This could be integrated with nationally-based systems such as Terrestrial and Freshwater Biodiversity Information System (TFBIS).
7.2.2 Implement a data management system. A comprehensive Council-wide neEDS analysis has been undertaken and a software package has been chosen after a thorough decision process.
7.2.3
Development of Web-based reporting systems to ensure that up-to date information is delivered to the public, thereby adding a lot more value to this monitoring programme. This should not replace the production of more detailed reports, such as this, or oral delivery of this information, such as at planned seminars and road shows.
7.2.4 Develop the NCS consents database so that consents can be sorted by land use or activity type within a catchment or area and output plotted on a map. This is necessary for trying to
June 2005
determine cause and effect. However, this sorting is a very tedious manual process at present. 7.3 Internal Communications Strategy As environmental issues emerge through complaints and monitoring, systems for efficient and effective feedback between consents, planning, resource science, parks and reserves and engineering should be developed. 7.4 Resource Consent Processing Consent decisions should be better peer reviewed and discharges to water should include receiving water monitoring where appropriate. Ensuring resource consents for discharges to water, including stormwater, are processed in a timely fashion for higher risk industrial activities. A greater emphasis should be placed on receiving water sampling to determine loadings from individual activities. 7.5 Compliance Monitoring 7.5.1 Resources for compliance monitoring activity should be increased, particularly in the short-term with respect to the following: (a) dairy farming discharges to land and water, stock crossings, feed pads and stand-off pads, stock access to waterways and management of wetlands. The frequency of monitoring of such activities should be increased to biennial at least and biannual for discharges of dairy farm effluent to water. Farmers should be assisted in defining priorities for improving environmental performance on their farm based on environmental risk. This should go hand in hand with education, particularly around the Clean Streams Accord, which is about to be signed by Fonterra and TDC. A road show on this topic is planned for mid-June. (b) discharges, including stormwater from higher risk industrial activities such as landfills, timber treatment facilities and workshops. 7.5.2 More effective recording of complaints to be able to determine a more representative summary of public opinion. High priority and low cost. 7.6 Education Provide more advice and assistance to those resource users who need to improve their performance. June 2005
8 REFERENCES APHA 1998: Standard methods for the examination of water and wastewater 20th edition. (Eds. L S Clesceri, A E Greenberg, A D Eaton). Published by the American Public Health Association, the American Water Works Association and the Water Environment Federation. 1220p. ANZECC 1992: Australian water quality guidelines for fresh and marine waters. Australian & New Zealand Environment & Conservation Council. ANZECC and ARMCANZ 2000: Australian and New Zealand guidelines for fresh and marine water quality. Australia and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand. Basher, L R Ed., 2003: The Motueka and Riwaka Catchments. A Technical Report summarising the present state of Knowledge of the Catchments, Management Issues, and Research Needs for Integrated Catchment Management. Biggs, BJF & Kilroy, C, 2000: Stream periphyton monitoring manual. NIWA, Christchurch. 226p. Boothroyd, IKG; Stark, J D, 2000: Use of invertebrates in monitoring. In: Collier, K J; Winterbourn, M J, eds. New Zealand Stream invertebrates: ecology and implications for management. New Zealand Limnological Society, Christchurch. pp. 344-373. Bruce, K A; Stark, J D, Gillespie, P A (1987): Motueka River Aquatic Biological Studies. Literature Review and Pilot Study. Cawthron Report for Nelson Catchment Board. CCREM 1987: Canadian water quality guidelines. Canadian Council of Resource and Environment Ministers, Inland Water Directorate, Environment Canada, Ottawa. Broome, K.G.,. Fairweather, A.A.C. & Fisher, P (Compilers), 2005. Sodium fluoroacetate, A review of current knowledge. Davies-Colley, R J; Nagels, J W; Smith, R; Young, R.G.; Phillips, C, 2004: Water Quality Impact a dairy cow herd crossing a stream, the Sherry River, New Zealand. NZ Journal of Marine and Freshwater Research 38:569-576. Davies-Colley, R J, 1988: Measuring water clarity with a black disk. Limnology and Oceanography 33. pp. 616-623. Easton, J, 2005: Impact of Stormwater Sediment on Richmond Estuary ­ Report for Tasman District Council Environment and Planning Committee. Report #: EP05/03/07. Fahey, B D; Duncan, M J; Quinn, J M, 2004: Impacts of forestry. In Harding, J S; Mosely, M P; Pearson, C; Sorrell, B (eds.) Freshwaters of New Zealand. New Zealand Hydrological Society and New Zealand Limnological Society. pp. 33.1 ­ 33.16. Fonterra Co-operative Group, 2004: 2003/2004 Environmental and animal welfare Survey Report. Graynoth, 1992. Long-term Effects of Logging Practices in Golden Downs State Forest, Nelson. pp. 52-69 in NZ Freshwater Fisheries Report 136, MAF Fisheries, Christchurch. Harding, J S; Young, R G; Hayes, J W; Shearer, K A; Stark, J D, 1999: Changes in agricultural intensity and river health along a river continuum. Freshwater Biology 42. pp. 345-357. Harding, J S; Quinn, J M; Hickey, C W, 2000: Effects of mining and production forestry. In: Collier, K J; Winterbourn, M J, eds. New Zealand Stream invertebrates: ecology and implications for management. New Zealand Limnological Society, Christchurch. pp. 230-259. Hewitt, T. 2002. A Study of the Effects of Forest Management Practices on Sediment Yields in Granitic Terrain in Motueka Forest James, T, 2004: State of Surface Water Quality in the Buller Catchment. Report for TDC Resource Management Policy Committee, November 2004. Kelly, D; McKerchar, A; and Hicks, M, 2005: Making Concrete: Ecological Implications of Gravel Extraction. Water and Atmosphere 13(1) 2005. June 2005
Larned, S T; Scarsbrook, M R; Snelder, T H; Norton, N J; Biggs, BJF, 2004: Water quality in low elevation streams and rivers of New Zealand: recent state and trends in contrasting landcover classes. New Zealand Journal of Marine and Freshwater Research 38. pp. 347-366. MacGibbon, J, 1998: Ecological Survey of Rivers of the Takaka Catchment. Tasman District Council report. MacGibbon, J, 2000: How Healthy are our Rivers? The State of Rivers in Tasman District 19992000. Tasman District Council report. Milson, P, April 2004: Compliance Monitoring Project: Apple Dump Wastewater Disposal. Milson, P, May 2004: Compliance Monitoring Project: Winery Waste Disposal Ministry for the Environment and Ministry of Health 2003: Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas. Ministry for the Environment, 1999: Ambient Concentrations of Selected Organochlorines in Estuaries. June 1999. Authors: Scobie, S; Buckland, S; Ellis, H; and Salter, R. Ministry for the Environment 1998: Environmental performance indicators ­ confirmed indicators for air, fresh water and land. Ministry for the Environment, Wellington. Nottage, R, 2000: Water Quality of the Aorere River and its Tributaries, Golden Bay. Parkyn, S M; Wilcock, R J, 2004: Impacts of agricultural land use. In Harding, J S; Mosely, M P; Pearson, C; Sorrell, B (eds.) Freshwaters of New Zealand. New Zealand Hydrological Society and New Zealand Limnological Society. pp. 34.1 ­ 34.16. Quinn, J M; Cooper, A B; Davies-Colley, R J; Rutherford, J C; Williamson, R B, 1997: Land-use effects on habitat, water quality, periphyton, and benthic invertebrates in Waikato, New Zealand, hill-country streams. New Zealand Journal of Marine and Freshwater Research 31. pp. 579-598. Quinn, J M, 2000: Effects of pastoral development. In: Collier, K J; Winterbourn, M J, eds. New Zealand Stream invertebrates: ecology and implications for management. New Zealand Limnological Society, Christchurch. pp. 208-229. Roberts, R, 1993: A Survey of the Biology and Water Quality of Rivers in the Takaka Catchment, Nelson. Report for the Nelson-Marlborough Regional Council. Cawthron Report No 231. Scarsbrook, M R; McBride, C G; McBride, G B; Bryers, G G, 2003: Effects of climate variability on rivers and consequences for long-term trend analysis. Journal of the American Water Resources Association 39. pp. 1435-1447. Smith, D G; Maasdam, R, 1994: New Zealand's National River Water Quality Network 1. Design and physico-chemical characterisation. New Zealand Journal of Marine and Freshwater Research 28. pp. 19-35. Smith, D G; McBride, G B; Bryers, G G; Wisse, J; Mink, DFJ, 1996: Trends in New Zealand's National River Water Quality Network. New Zealand Journal of Marine and Freshwater Research 30. pp. 485-500. Shelder, T; Biggs, B; Weatherhead, M. 2004: New Zealand River Environment Classification User Guide. Ministry for the Environment, Wellington. Stark, J D, 1985: A macroinvertebrate community index of water quality for stony streams. Water & Soil Miscellaneous Publication 87. 53p. Stark, J D, 1990: Macroinvertebrate Communities in the Motueka and Riwaka Catchments. Cawthron Report for Nelson-Marlborough Regional Council. Stark, J D, 1990: Aquatic Studies in the Waimea River Catchment. Cawthron Report for Nelson Catchment Board and Regional Water Board. Stark, J D, 1993: Performance of the macroinvertebrate community index: effects of sampling method, sample replication, water depth, current velocity and substratum on index values. New Zealand Journal of Marine & Freshwater Research 27. pp.463-478. Stark, J D, 1998: SQMCI: a biotic index for macroinvertebrate coded-abundance data. New Zealand Journal of Marine & Freshwater Research 32. pp. 55-66. Stark, J D; Boothroyd, IKG; Harding, J S; Maxted, J R; Scarsbrook, M R, 2001: Protocols for sampling macroinvertebrates in wadeable streams. New Zealand Macroinvertebrate June 2005
Working Group Report No. 1. Prepared for the Ministry for the Environment. Sustainable Management Fund Project No. 5103. 57p. Suren, A M, 2000: Effects of urbanisation. In: Collier, K J; Winterbourn, M J, eds. New Zealand Stream invertebrates: ecology and implications for management. New Zealand Limnological Society, Christchurch. pp. 260-288. Suren, A M; Elliott, S, 2004: Impacts of urbanisation on streams. In Harding, J S; Mosely, M P; Pearson, C; Sorrell, B (eds). Freshwaters of New Zealand. New Zealand Hydrological Society and New Zealand Limnological Society. pp. 35.1 ­ 35.17. Tasman District Council: Surface Water Quality Monitoring Programme, January, 2005 Tasman District Council, 2000: Environment Today, Tasman District Council "State of the Environment" Report, MacGibbon Ed. Thoma, K 1997: Reconnaissance Survey of Soils, Land Use and Water Quality in the Motupipi River Catchment. Report for Tasman District Council. Vant, B; Wilson, B, 1998: Trends in river water quality in the Waikato Region, 1980-97. Environment Waikato technical report 1998/13. Environment Waikato, Hamilton. Wilcock, R J, 1986: Agricultural run-off: a source of water pollution in New Zealand? New Zealand Journal of Agricultural Science 20. pp. 98-103. Young, R G; Quarterman, A J; Eyles, R F; Smith, R A; Bowden, W B, in press: Water quality and thermal regime of the Motueka River: influences of land cover, geology and position in the catchment. New Zealand Journal of Marine and Freshwater Research. Young, RG, Harding, JS, Strickland RR, Stark, JD, Shearer, KA, Hayes, JW. 2000. Cobb Power Scheme resource consent renewal: Water quality, aquatic habitat and fisheries. Prepared for TransAlta. Cawthron Report 554. June 2005

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