Integrating hydrology, freshwater ecologyand social processes research for

catchment-scale management

A Pearce, Landcare Research, New ZealandWB Bowden, Landcare Research, New ZealandT Dunne, University of California, Santa Barbara, USAA Fenemor, Tasman District Council, New ZealandJ Harding, Cawthron Institute, New ZealandG Likens, Institute of Ecosystem Studies, New York, USA

Motueka catchmentNew Zealand

• an example of a HELP catchment• a real catchment (2000+km2) - not an experimental catchment• real issues: - land-use effects on water yield - conflict over surface and ground water use - low flow and sediment impacts on trout fishery - land-use effects on water quality (nutrients, bacteria)• how can research help to manage the effects of all uses, and to resolve or manage conflicts over resources

Why the Motueka catchment?

! a ‘microcosm’ of New Zealand

! land uses- mountains (1600+m) to sea; 3500+mm rainfall to <1000 mm- national & conservation parks in primary forest - tourism,

conservation- extensive plantation forests- sheep and beef farming on hills, changing to plantations

- dairy farming on valley floors - supplementary irrigation- berry fruit, hops, kiwi fruit under irrigation on valley floors

and flood plain

Why the Motueka catchment?

! a ‘microcosm’ of New Zealand

! conflicts- forest harvesting on some hill country generates a lot of fine

sediment- sediment damage to trout habitat and fishery- conflict over surface water – irrigation vs minimum flow/fish

habitat- legal action to protect minimum low flow for trout fishery- livestock access to streams causes nutrient and bacterial

contamination- conflict over ground water use

– near-stream extraction vs low flows– plantations vs ground water recharge

Simplified geology and rainfall distribution in the Motueka catchment.

Primary forest in high-rainfall upper catchment. Used for biodiversity conservation, tourism, recreation.

Natural and plantation forests on gravel hill country, mid-upper catchment

Recently harvested plantations on gravel hill country. Little erosion or sediment impacts in contrast to the harsh visual

impact.

Roads and recent harvesting in plantations on granite hill country. Large amounts of fine sediment produced from roads and harvested areas is transported into streams.

Mixed land uses in mid-catchment, gravel hill country near Tapawera. Irrigated horticulture on terraces near

stream. Typical main-stem stream channel.

Intensive horticulture on valley flats. Sheep/cattle grazing and plantations on gravel hill country.

Gravel hill country inferred to be recharge zone for aquifers. Plantations restricted to 25% of total area here.

“Lifestyle” small farms on gravel hill country near the coast.

Lower reaches of Motueka River and small flood plain surrounding outlet to Tasman Bay.

Intensive horticulture on Motueka River flood plan and terraces close to outlet to Tasman Bay.

Overview of process

! Initial 2-day meeting of 40 stakeholders and users to scoperegional issues and research opportunities, March 1998- report sent to all attendees

! Follow-up discussions in 1998 and 1999 to confirm issuesidentified- consensus emerges on key issues, and Motueka catchment

as research focus- Tasman District Council (TDC) supports proposals

! International experts (Dunne and Likens) agree mid-1999 toundertake review and design project in early 2000

! Experts convene for 3 weeks in New Zealand for next 3 stages

Overview of process

! Four interest-group meetings to check & refine issues identified(Jan 2000)- upstream farmers- downstream farmers- iwi & economic sector representatives- marine resource users

! Seven meetings with research staff of Cawthron, Landcare Research, TDCand 5 other collaborating research institutes- define key researchable questions

! Expert panel reports on issues, researchable questions, and proposedresearch Feb 2000

! Research agreed with funders and implemented (July 2000 onwards)

! A questionnaire sent to 160 community stakeholders to prioritise catchmentresearch issues

The key issues

Water! Effects of plantation forestry on stream-flow & ground water

recharge

! Effect of near-stream ground water pumping on low stream-flows

! Effect of floods on stratifying Tasman Bay and transportingsediment, chemical and microbial contaminants to shellfish beds

Sediment! Risk to channels and trout habitat from sediment supplied after

forest harvesting

! Short and long-term sediment impacts in Tasman Bay(very shallow)

The key issues

Water quality! Nitrogen and bacterial loads in downstream reaches and Tasman Bay

! Animal access to streams and berry fruit irrigation fertiliser suspected

Aquatic biota! Significant decline in famous trout fishery - diametrically opposed

views on causes

! Concerns about native fish, invertebrates, and maintaining freshwaterbiodiversity

Riparian zones! No consensus and little information on condition of riparian zones,

their effect on water quality, or habitat for birds & other terrestrial biota

The researchable questions

! Compile historical information on Motueka catchment fromearly settlement by humans (<1000 years ago) to the present

! The ground and surface water supply

! Sources and dispersal of sediment

! Nature and spatial distribution of aquatic habitat

! Nature, distribution and function of riparian zones

! Water quality and the export of nutrients and contaminants toTasman Bay

! Designing how research results are to be used in decision-making and evaluating how, and what, learning occurs in sucha process

Research for the first 2 years

Knowledge integration and delivery for ICM

! construct knowledge base of historic and current environmentwith key users & stakeholders (maps, databases, narrative)

! develop web site for access, retrieval and contributions

! establish and work with Community Advisory Group forcommunity involvement and communication

Research for the first 2 years

Land-use influences on water quality and quantity

! quantify components of surface water balance for the major land usesand land forms

! quantify primary components of sub-surface water balance for primaryaquifers in the upper catchment

! simulate catchment-wide water balance with simple, fast spatiallyexplicit model for current, historic and future land use scenarios

! produce model results as visualisations, incorporate into knowledgebase and discuss them with users and community groups

! determine key gaps in process knowledge to refine these simulationsand design field experiments to fill the highest priority gaps (futurework)

! design and establish network of environmental sampling stations forwater, sediment, nutrients, contaminants and pathogens

Research for the first 2 years

Riparian Zones

! develop typology of riparian zones and map the catchment

! place maps on website

! establish study of stream health, habitat quality and riparianconditions at representative sites

Research for the first 2 years

Land-use effects on fresh water & coastal ecosystems

! develop model of whole stream benthic invertebrate production

! produce GIS maps of distribution of substrate types and biotafor inter-tidal and delta zones

! develop conceptual coastal ecosystem model for distribution ofmicroalgae over scallop beds in Motueka river plume

! determine dynamics of microalgal community structure andquantity/quality of suspended particulates in near-bottomwaters

Research for the first 2 years

Social learning

! work with stakeholders and tangata whenua to develop ways to linkdiverse knowledge bases, improve uptake and enhance learning

! use these findings to develop and improve web site and simulationmodels

! trial participatory approach to further develop research priorities &management tools for 2 selected issues

! estimate marginal economic benefits to anglers from maintainingfish habitat, and to land users from water used for irrigation

! develop and test indicators of understanding and use of science inintegrated catchment management

What might be useful elsewherein HELP?

The major elements of the design process should be transferable:

! Consultation with relevant, interested communities about thekey real-world issues

! Researchers then determine which issues are researchableusing current scientific methods, and those which are not

! Collaborative design of the research, including how it will beconducted and incorporated into learning by managers, policymakers and researchers

! Communal definition of conceptual models of how catchment-scale mechanisms operate, interact and exert downstreameffects

What might be useful elsewherein HELP?

! Concerted effort to gather historic information on climate, landuse, social/economic change to help: check model predictionsusing past conditions; envision future states of the catchment

! Formalise conceptual models into simulation modelsappropriate for integrated management use

! Field data collection for biophysical, social and economicprocesses

! Exploring scenarios of change and variability to guidemanagement and process decisions