The water quality challenge
Over the past twenty years, rural land use in Canterbury has changed. Over the same time period, the amount of nutrients reaching waterways has increased, and this has led in some areas to a decline in water quality.
The need to manage water effectively in the region has led in recent years to the collaboratively-developed Canterbury Water Management Strategy and this is now being implemented. This strategy seeks to enable present and future generations to gain the greatest social, economic, recreational and cultural benefits from the region’s water within an environmentally sustainable framework.
The strategy sets out water quality targets, requires the establishment of catchment limits for nitrate and other contaminants, and supports primary sector initiatives to improve land management practices.
In addition to the strategy, the Government’s Proposed National Policy Statement for Water has now set a national goal of phasing out the contamination of fresh water.
Project aims, benefits
The Land Use and Water Quality project is working alongside the Canterbury Water Management Strategy, and is complementary to it. It has a science aspect which aims to assess the effects of land use changes on the region’s groundwater, streams, rivers and their associated ecosystems.
It also involves extensive work with the community to develop processes and tools which can be used by people in the catchment to reduce and/or avoid nutrient run-off and leaching into waterways. The project will ultimately result in a more effective policy framework for establishing limits for nitrate and other contaminants, and management strategies for improving water quality.
Environment Canterbury is working with Ngāi Tahu, the primary sector, and other stakeholders in a collaborative style to ensure solutions are workable and sensible while being science-informed. The outcome will be a range of preferred approaches for managing the impact of land use change on water quality, with these approaches supported and driven by primary industry and Environment Canterbury.
Benefits
The outcomes of the project will be relevant to other catchments in the region and within New Zealand. The project team will be working closely with the team implementing the Canterbury Water Management Strategy.
Participants
- Environment Canterbury
- DairyNZ
- Federated Farmers
- Horticulture New Zealand
- Irrigation New Zealand
- The Foundation for Arable Research
- Fish & Game
- Forest & Bird
With support from the Crown Research Institutes AgResearch, Landcare Research, ESR and NIWA.
Hurunui case-study
The project is taking a case-study approach with an initial focus on the Hurunui catchment in North Canterbury. The lessons learnt from this catchment will be applied to other areas across the region.
Critical to the project will be: scientific work to establish the implications of different nutrient limits; identifying which parts of the catchment are more susceptible to contaminant losses; modelling to predict the effects of changing land uses; and determining the implications of trends to more intensive land-uses and management practices on surface and groundwater quality.
The work also includes activities at three levels: with land users working on-farm; people living and working within the catchment; and with people working at a regional level to look at the links between economic, social and environmental factors.
The workshops will identify issues and workable solutions to overcome barriers to the take-up of any tools and processes.
The Hurunui catchment
The case-study area consists of the mid and upper catchment areas of the Hurunui River including the Pahau and Waitohi river catchments. Environment Canterbury is already working with landowners to address water quality problems in this area. The communities with an interest in the Waiau and Hurunui Rivers are also part of a project reviewing and establishing environmental flows for the rivers.
In addition, the area:
- is representative of the surface and groundwater environment in Canterbury
- has reasonable surface and groundwater quality records
- has surface and groundwater hydrology which is known
- incorporates a mix of intensive and extensive land uses
- is likely to undergo further land use intensification in the future.
It is also of a size whereby the scope of the project is manageable.
Resources and reports
The reports listed below are some of the background research that is helping to inform the Planning Process.
Environment Canterbury holds a number of technical reports on various aspects on the Hurunui Catchment. A brief summary of these reports is included below.
Nutrient Management in Hurunui: A Case Study in Identifying Options and Opportunities - November 2011
This report records the main conclusions of the pilot study of how the cumulative effects of land use on water quality should be managed in the Hurunui catchment.
Nutrient Management in Hurunui: A Case Study in Identifying Options and Opportunities (pdf 2.32 MB)
Estimating nitrate-nitrogen leaching rates under rural land uses in Canterbury - September 2010
This report summarises the contributing work and the approach used to develop a set of nitrate-N leaching rates for a range of land uses in Canterbury, henceforth referred to in this report as the “lookup table”.
Estimating nitrate-nitrogen leaching rates under rural land uses in Canterbury (pdf 2.22 MB)
Mapping of vulnerability of nitrate and phosphorus leaching, microbial bypass flow, and soil runoff potential for two areas of Canterbury - June 2010
This report models and maps the vulnerability of land to leach nitrogen and phosphorus, to promote phosphorus (and sediment) enriched runoff, and to leach microbes from agricultural land to aquifers and/or transport them to streams in two case study areas. It also models and maps the optimal riparian buffer width to trap bacteria in overland flow.
Mapping of vulnerability of nitrate and phosphorus leaching, microbial bypass flow, and soil runoff potential for two areas of Canterbury (pdf 2.32 MB)
Critical review of contaminant transport time through the Vadose Zone: M Close ESR - August 2010
This report reviews existing knowledge on vadose zone travel processes and their impact on groundwater quality and the information that is available from studies relevant to the Canterbury Plains. There are several different types of information and studies including the response of groundwater nitrate concentrations to major recharge events and land use change, tracing experiments using a range of tracers under varying recharge conditions, and age dating of groundwater.
Critical review of contaminant transport time through the Vadose Zone (pdf 1.30 MB)
Current nutrient loads and options for nutrient load limits for a case study catchment: Hurunui catchment: Ned Norton, David Kelly August 2010
Several tasks are addressed in this report including:
- calculating current nutrient loads;
- reviewing methods for determining load limits;
- identifying a range of options for numeric objectives and nutrient concentration standards; and
- calculating nutrient standard load limits for each option.
Current nutrient loads and options for nutrient load limits for a case study catchment: Hurunui catchment (pdf 2.58 MB)
Depth to Groundwater in the Culverden Basin: PDP 30 June 2010
Environment Canterbury have engaged Pattle Delamore Partners Ltd (PDP) to prepare a map of the Culverden Basin showing the average depth of groundwater from the land surface. The work is being carried out to assist Environment Canterbury staff with the preparation of NRRP Variation 27 – Managing non-point source discharges. This letter presents the methodology for deriving the depth to groundwater contours, the assumptions made and the limitations encountered during the study.
Depth to Groundwater in the Culverden Basin (pdf 92 kB)
Figure 1 : Location of Culverden Basin (pdf 1.53 MB)
Figure 2 : Culverden Basin Showing Major Rivers and Leonard Mound (pdf 4.17 MB)
Figure 3 : Piezometric Contour Map of Average Water Table Elevation (pdf 3.56 MB)
Figure 4 : Average Depth to Groundwater Contours (pdf 4.13 MB)
Figure 5 : Average Depth to Groundwater Contours in Relation to the Data Sources (pdf 4.10 MB)
A review of nitrate toxicity to freshwater aquatic species: C. W. Hickey, M.L. Martin 2009
Environment Canterbury commissioned a review of the ANZECC (2000) and the 2002 revised guideline value freshwater quality guidelines for chronic nitrate (NO3-N) concentrations in surface waters and groundwaters, together with advice on application of guidelines to seasonally varying concentrations (i.e., in groundwaters, rivers and lowland streams). Specific consideration was also requested regarding the availability of data for indigenous and representative species, together with introduced species resident in Canterbury's aquatic ecosystems.
A review of nitrate toxicity to freshwater aquatic species (pdf 1.64 MB)
Seven day mean annual low flow mapping in the Hurunui Catchment: S Facer 2003
This report summarises the project undertaken by Environment Canterbury to estimate the “natural” low flows for tributaries of the Hurunui River from spot gaugings and recorded flows.
Seven day mean annual low flow mapping: Facer 2003 (pdf 6.42 MB)
Hurunui River Catchment: Tangata Whenua Values Report: H Crengle 2002
This report describes the cultural values and traditional relationship with ancestral lands, water sites, wahi tapu and other taonga associated with rivers and streams in the Hurunui Catchment. It also identifies the outcomes that Tangata Whenua are seeking in terms of river flows and water quality and what Tangata Whenua would not like to see.
Tangata Whenua Values Report: H Crengle 2002 (pdf 8.27 MB)
Hurunui River - Results of water quality monitoring: January 1989 to December 1999: S Hayward 2001
This report summarises the analysis of water quality samples on the Hurunui River. Water quality monitoring at four sites on the Hurunui River has been undertaken by Environment Canterbury on a quarterly basis since August 1993. In addition to quarterly sampling, an intensive sampling survey was undertaken in 1997/98. In an independent monitoring programme, NIWA staff have collected water quality samples monthly from two sites on the Hurunui River since 1989. Both sets of data were analysed for seasonal, temporal and spatial trends, and compared to relevant water quality guidelines.
Hurunui River - Results of water quality monitoring: January 1989 to December 1999: S Hayward 2001 (pdf 4.01 MB)
Hurunui River: Instream Values and Flow Regime: Dr P Mosley 2002
This report reviews the natural, heritage and amenity values of the Hurunui River system and outlines their relationship to the natural and managed flow regime.
Hurunui River Instream values and flow regime: Mosley 2002 (pdf 21.58 MB)
Hurunui River habitat 2-D modelling: NIWA 2004
This report outlines the methodology and results of a 2-D hydrodynamic modelling study carried out in the Hurunui River in 2004. This report provides independent information upon which recommendations for minimum flows can be made, based on an instream habitat assessment using two dimensional (2-D) hydrodynamic modelling for prediction of depths and velocities for flows from 5 to 80 m3/s. This report suggests alternative monthly minimum flow regimes dependent upon different management objectives.
Hurunui River habitat 2-D modelling: NIWA 2004 (pdf 7.34 MB)
A desktop assessment of the effects of groundwater abstraction on surface water flow in the Hurunui River catchment: J Weeber 2002
This report provides a desktop investigation provides an estimation of the magnitude of stream depletion in the Hurunui River catchment due to groundwater abstraction.
A desktop assessment of the effects of groundwater abstraction on surface water flow in the Hurunui River catchment: J Weeber 2002 (pdf 1.85 MB)
Economic Impact Analysis of options for the flow regime and allocation of water from the Hurunui River: S Ford 2004
This documents reports the results of analysis of reliability of supply under two river flow regimes, the existing and that proposed by Dr Mosley at two different A permit allocations, 7.5 and 10 cumecs. It reports the impact on individual land uses and the District / Region as a whole.
Economic Impact Analysis of options for the flow regime and allocation of water from the Hurunui River: S Ford 2004 (pdf 1.39 MB)
The Effects of Alternative Hurunui River Allocation Regimes on Abstractive Users: Aqualinc 2005
This report explores the effects of the proposed flow regime on existing abstractive users of Hurunui water while considering “A” and “B” permit allocation impacts and effects on both the abstractors and the river.
The Effects of Alternative Hurunui River Allocation Regimes on Abstractive Users: Aqualinc 2005 (pdf 750 kB)
Planning Report Hurunui River and Tributaries: Environmental flow and water allocation: H Familton 2007
This report summarises the purpose, consultation process, findings and conclusions in reviewing the minimum flows of the Hurunui River and tributaries.
Planning Report Hurunui River and Tributaries: Environmental flow and water allocation: H Familton 2007 (pdf 20.16 MB)
Hurunui River Recreation Study 2000 to 2001: R Greenaway 2001
This report summarises the findings of a survey of recreational visitors to the Hurunui River Catchment over the summer of 2000/01 and Easter 2001. The report is presented in two parts. Part One is a summary and analysis of all data gathered during the research project. Part Two is a presentation to the quantitative survey data as a technical report.
Hurunui River Recreation Study 2000 to 2001: R Greenaway 2001 (pdf 12.51 MB)
Groundwater quality investigation of the Culverden Basin: P Abraham & C Hanson 2006
This report presents the results of a ground water quality investigation conducted by Environment Canterbury in the Culverden Basin in the late summer of 2006. The main aim was to collect infill samples from areas without any groundwater quality data so as to provide a better spatial distribution of available information. In addition land use, sources of contamination and groundwater recharge are also discussed.
Groundwater quality investigation of the Culverden Basin: P Abraham & C Hanson 2006 (pdf 2.28 MB)
Hurunui River - Influence of the middle reach tributaries on water quality of the lower Hurunui River (2005-2008): O Ausseil 2010
This report presents the analysis of the water quality data relating to nutrients and indicator bacteria collected by Environment Canterbury between November 2005 and March 2008, on the middle Hurunui catchment between SH7 and SH1.
Hurunui River - Influence of the middle reach tributaries on water quality of the lower Hurunui River (2005-2008): O Ausseil 2010 (pdf 1.23 MB)
Catchment Workshop 3 - October 27, 2010
This workshop focused on reviewing the stakeholder assessment of the 3 previous scenarios:
- Current,
- Business as usual 20 years out, and
- Extensive irrigation development 20 years out.
The groups were given the opportunity to revisit their judgements and then compare them with all the other stakeholder groups. The groups also had the opportunity to question other stakeholder groups about some of their judgements to assist in understanding.
The information from catchment 2 was taken and used to inform 2 new scenarios and guide the analysis. Stakeholders reviewed the 2 new scenarios and made their judgements on these.
During the evening there were also 4 presentations - copies of which are below:
Deliberation (pdf 102 kB)
Catchment Workshop 2 - September 29, 2010
Workshop 2 focused on deliberating the impact of the current state of land and water and two future land use intensification scenarios. This involved:
- Stakeholder groups verifying the system diagram
- Stakeholder groups identifying a set of things they value that they will use to assess the impact of the 3 states
- Science group presentations (below) on information on the current state of land use and 2 future intensification scenarios
- Stakeholder groups then making a judgement on the acceptability of the three states using their values and noting the reasons for the choice will be recorded to enable the different stakeholder judgements to be made transparent, with the process allowing for in depth conversations that will inform the design of preferred approaches.
Catchment Workshop 1 - September 16, 2010
The first catchment workshop was held on 16 September with an excellent mix of stakeholders present.
The first part of the session was spent listening to presentations on what we know about the current state in the catchment. Copies of these presentations are below:
This was followed by the stakeholder discussion and brainstorming on the issues. The issues discussion has been summarised in the Gp Feedback Summary - What are the factors and relationships that link land (pdf 38 kB) - these are from the post-it note session.
The facilitation team have been working on bringing together the causal loop diagram (CLD) and this will be presented back at the next workshop. One of the tasks at the next workshop is to review both the feedback paper and the CLD to verify they are correct interpretations of the information given at the workshop.
The homework for the group was to take the values paper (as below) and talk to other stakeholders and members of their own group to identify values and indicators for discussion at the next workshop.
Values paper (pdf 52 kB)
Summary of Methodology on Integrating deliberative and systems dynamics approaches (pdf 109 kB)
Case-study introduction session - Culverden 13 July 2010
The following information is copies of the papers and PowerPoint presentations that were available at the workshop in Culverden on 13 July 2010.
Denise Bewsill presentation (pdf 460 kB)
Ian Whitehouse presentation (pdf 575 kB)
Frequently asked questions (pdf 140 kB)
Ken Taylor presentation (pdf 1.15 MB)
Briefing notes (pdf 198 kB)