Arthington, AH

Brizga, SO

Kapitzke, IR

ResearchOnline at James Cook University

1 INTRODUCTION  Water resource planning policies and practice in Australia, like many other countries, now recognise the environment as a legitimate water user, defining water allocations both for consumptive use and for environmental purposes (see Arthington & Pusey 2003, Brizga et al. 2002, Naiman et al. 2002). Provi-sion of water for the environment (environmental flows) attempts to redress alterations to natural river flow regimes and other threats to river ecosystem health resulting from water resource development (e.g. impoundments, flow supplementation, water extractions) and other development pressures in and adjacent to watercourses (e.g. urbanisation, infra-structure encroachment, channel modifications). River flow regimes are key drivers sustaining the biological diversity and ecological integrity of riv-ers, wetlands, estuarine and near shore marine envi-ronments (Poff et al. 1997, Bunn & Arthington 2002). The object of providing environmental flows is to sustain the ecological values of aquatic ecosys-tems at an acceptable level of risk.  Water resource planning strategies to meet multi-purpose requirements of water for consumptive use and the environment are, in effect, environmental impact assessment studies that examine present wa-ter resource development and future water manage-ment scenarios from bio-physical, socio-cultural and economic perspectives. To determine environmental flows in the context of the whole river ecosystem, and to predict the manner in which various water re-source development or remediation scenarios may further impact ecological values, water planners need to understand how a stream’s bio-physical con-dition is presently affected by water resource and other development pressures. Impact assessment ap-proaches can be used effectively here. Environmental flow determination for water re-source planning in Queensland, Australia uses the Benchmarking Methodology (Brizga et al. 2002), a whole of system (holistic) approach that establishes relationships between water resource and other de-velopment pressures and the geomorphological and ecological condition of the entire waterway from source to sea. The Benchmarking Methodology de-fines condition indicators for flow (hydrological sta-tistics) and how water is taken, and using risk as-sessment and conceptual link models (based on literature and professional experience), assesses the performance of various environmental flow scenar-ios by examining the ecological implications of dif-ferent levels of departure of the flow indicators from natural values. The link models depict relationships between flow indicators (and other environmental factors) and riverine ecosystem components and functions, and describe interactions between the various ecosystem components. The risk assessment models provide a means of relating risk of ecologi-cal impacts to quantitative measures of flow regime change (flow indicators), and form the basis for set-ting targets for achievement of environmental flows (Brizga et al. 2002). Impact assessment tools for determination of environmental flows in water resource planning  I.R. Kapitzke School of Engineering, James Cook University, Queensland, Australia S.O. Brizga  S Brizga and Associates Pty Ltd, Melbourne, Australia A.H. Arthington Centre for Riverine Landscapes, Griffith University, Brisbane, Australia  ABSTRACT: Environmental impact assessment approaches are useful in water planning and environmental flow determination to identify water resource development and remediation strategies that meet multipurpose requirements for consumptive use and for environmental protection. Impact assessment tools introduced here (the development and remediation framework for water resource planning, the cause-effect relationship for development pressures and bio-physical condition, and the double field pressure-effect-impact matrix) will help water planners and managers to understand how a stream’s bio-physical condition is affected by water resource and other development pressures, to predict the suitability of various water resource development or remediation scenarios in meeting flow or non-flow related objectives, and to define indicators and criteria to be used in performance monitoring. This paper introduces several other impact as-sessment tools, which we believe will augment the Benchmarking Methodology and assist water re-source planning and environmental flow determina-tion. The proposed development and remediation framework and associated cause-effect relationships for water resource and other developments show the sequence of human-environment interactions that re-late water planning and management to bio-physical impacts on streams. The double field pressure-effect-impact matrix relates water resource and non-water resource development pressures to bio-physical impacts, through condition indicators for flow and how water is taken.  2 WATER RESOURCE DEVELOPMENT, REMEDIATION AND MANAGEMENT Water planning and provision of water for the envi-ronment, like other areas of sustainable resource management, may encompass mitigation of impacts to protect riverine ecosystems in new water resource development projects, or remediation of degraded ecosystems through restoration of flows in existing schemes (Naiman et al. 2002). Figure 1 (after Kapitzke 2003) shows a development and remedia-tion framework for water resource planning, which links the sequence of human activities, environ-mental impacts, development and remediation objec-tives, and mitigation and remediation measures within the context of the bio-physical and socio-cultural environment. The following discussion il-lustrates the framework components and introduces a formal process to document and assess cause-effect relationships that are central to this form of human-environment interaction. A remediation project (e.g. irrigation area reha-bilitation) usually starts with identified environ-mental impacts (bio-physical – e.g. wetland habitat degradation; or socio-cultural – e.g. inundation of road), which have resulted from existing water re-source development (e.g. dam construction, water harvesting), or from non-water resource develop-ment pressures (e.g. urbanisation, invasion of exotic species). Remediation objectives relating to flow (e.g. reinstate seasonality), and how water is taken (e.g. reduce habitat inundation) are then addressed through remediation measures for planning (e.g. identify redundant impoundments), infrastructure (e.g. provision for fish passage), and operations (e.g. flow release timing, blue-green algae management). On the other hand, a new water resource devel-opment project (e.g. water for agriculture or town-ship) starts with a need or aspiration, and develop-ment objectives related to flow (e.g. capture flood flows) and how water is taken (e.g. draw water from variable level intake). Mitigation measures relating to planning (e.g. water use efficiency), infrastructure (e.g. offstream storages), and operations (e.g. emu-lating natural water levels) may be embodied in the adopted water resource development infrastructure (e.g. flood harvesting storage) and flow regime (e.g. storage release strategies for improved water qual-ity). Nevertheless, some environmental impacts will remain (bio-physical – e.g. degraded riparian vegeta-tion; or socio-cultural – e.g. loss of agricultural land), and these in turn may require remediation. The central zone on the framework diagram (Fig. 1A) depicts the fundamentals of human-environment interactions, where human activity and the bio-physical and socio-cultural environment intersect, resulting in some form of bio-physical or socio-cultural impact. The cause-effect relationship dia-gram (Fig. 1B) links human activities (water re-source – e.g. dam construction; and other develop-ment – e.g. urbanisation) with bio-physical impacts (e.g. altered sediment processes, change in riffle macrophyte abundance, loss of fish species) by way of environmental effects relating to flow and how water is taken (e.g. changes in total flow volume, barriers to fish migration).     Figure 1. Development and remediation framework and cause-effect relationship for water resource planning B - Cause-effect relationship for water re-source and other development pressures on the bio-physical condition of streams Bio-geo-chemical processes Environmental effects (Condition indicators) How water is taken Flow Human activities     WRD Other Geomorphological & ecological impacts Bio-physical environment Non Water Resource Develop Infrastructure  Flow Water Resource Develop  Socio-cultural Bio-physical Environmental impact  Socio-cultural Bio-physicalEnvironmental impact  How water is taken FlowDevelopment objectives - WRD Planning Infrastructure Mitigation measures Operation Water Resource DevelopmentInfrastructure Flow  How water is taken Flow Remediation objectives - WRD  Planning Infrastructure Remediation measures Operation Human-environment interaction and cause-effect relationship Bio-physical and socio-cultural environment Development project Remediation project A – Framework for water resource management practices and environmental impacts  Water planners and managers must understand these interactions to meet multipurpose requirements for human use and protection of environmental processes and function in water resource remedia-tion or development projects.  3 LINKING PRESSURES, CONDITION INDICATORS & BIO-PHYSICAL IMPACTS As the bio-physical condition of streams is affected by flow and non-flow related pressures, a major challenge in water planning and the determination of environmental flows is to separate impacts related to modified flow regime from impacts associated with how water is taken and other development pressures (Brizga et al. 2002). Several interrelated causal mechanisms operate over different temporal and spatial scales, and it is often difficult to determine which attributes of an altered flow regime or other forms of human intervention are directly responsible for observed or predicted impacts, and the ecological condition of a stream. Environmental impact as-sessment (EIA) tools such as matrices are beneficial here to scope human-environment interactions and to understand cause-effect relationships. A double field matrix based on the Sanchez & Hacking (2002) activity-aspect-environmental impact model can be used to evaluate pressures (human activities), bio-physical impacts and their causes from an holistic or synoptic perspective, and to help identify appropri-ate mitigation or remediation measures. Table 1 is an abridged version of the double field pressure-effect-impact matrix, which depicts the re-lationship between water resource and other devel-opment pressures and bio-physical impacts on the stream. It introduces the notion of environmental ef-fects, which are processes set in motion or acceler-ated by human actions (e.g. altered flow regime). Whereas Table 1 deals only with hydrological [flow related] effects (e.g. total flow volume, seasonality, zero flows, low flows, high flows, floodplain flows), a more complete double field matrix could include non-flow related effects and associated condition in-dicators dealing with how water is taken (e.g. water level variations, water quality, habitat inundation, wetland quality, fish barriers). The left-hand field of the matrix shows flow re-lated environmental effects associated with water re-source development (e.g. dams, weirs, water har-vesting) and other catchment development pressures (e.g. grazing, forestry, urbanisation). The matrix can be expanded to include riparian (e.g. encroachment, exotic species invasion) and instream development pressures (e.g. river works, aggregate extraction), which will primarily affect stream bio-physical con-dition through non-flow related effects. The right-hand field shows how bio-physical im-pacts relate to particular flow related environmental effects. Table 1 limits this relationship to a selection of bio-physical impacts that includes geomorphol-ogy (e.g. altered channel morphology), hydraulic habitat (e.g. altered longitudinal connectivity), ter-restrial vegetation (e.g. riparian zonation change), aquatic invertebrates (e.g. lotic species community change), and fish (e.g. flood spawners community change). These impact categories can be expanded to encompass other ecosystem components including subsurface water, water quality, aquatic vegetation, and water dependent vertebrates. Similarly, expan-sion to include non-flow related environmental ef-fects would more completely present the relationship between development pressures and impacts. Each pressure may cause one or more effects, and each effect may have one or more impact. A three level ranking, showing pressure-effect and effect-impact relationships as very important, important, and minor, defines links between pressures and im-pacts, and identifies significant pathways via flow (and non-flow) related environmental effects. Each environmental effect has an associated condition in-dicator for flow and other impacts (e.g. flow volume in ML/year, water level variation in metres/day) that provides a measure of how stream condition is pres-ently affected by water resource and other develop-ment pressures. The condition indicator can also be used in setting targets for environmental condition and monitoring performance under various water re-source development or remediation scenarios.  4 ENVIRONMENTAL FLOW OBJECTIVES & WATER MANAGEMENT MEASURES The development and remediation framework for water resource planning, the cause-effect relation-ship for pressures and condition, and the double field pressure-effect-impact matrix will assist in the stra-tegic water planning process and in operational wa-ter planning and management. Water planners and managers can use the relationships developed through these impact assessment tools to establish appropriate water management measures to meet various flow or non-flow related objectives, and in the definition of indicators and criteria for use in monitoring performance against these objectives. The double field pressure-effect-impact matrix can also provide a formal basis for the development of detailed conceptual models to illustrate how various water resource and other pressures affect the water-way-riparian-estuarine ecosystem by way of the various types of flow regime change (or other envi-ronmental effects).   Table 1. Abridged double field pressure-effect-impact matrix showing impacts of water resource and other development pressures on geomorphological and ecological condition of streams (example pressures and impacts and indicative relationships only) Pressures - Human activities Geomorphological and ecological impacts on streams Water resource de-velopment Catchment de-velopment Environmental effects (Condition indicators) Geomor-phology Hydraulic habitat Terrestrial vegetation Aquatic in-vertebrates Fish Dam Weir / barrage Low flow extraction / diversion Water harvesting Supplementation Grazing Cropping Forestry Urbanisation             Hydrological effects  - Flow related Altered channel morphology Altered sedimentation processes Altered channel-floodplain processes Change in timing & extent of wetting Altered hydraulic diversity Altered longitudinal connectivity Zonation change for riparian species Community change for riparian species Community change for floodplain species Community change for obligate lotic species dtiCommunity change for aerial species Community change for estuarine / marine Community change for flood spawners Community change for low flow spawners Community change for estuarine / marine ? ? ? ? ? ? ? ? ? Total flow volune ? ? ?  ? ? ? ? ? ?  ? ? ? ? ? ? ? ? ?     Annual variability ? ? ?  ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Seasonality  ?  ?  ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?  ?  ? Zero flows  ?  ? ? ? ? ? ? ? ? ? ? ? ? ?  ? ? ? ? ? ? ? Low flows ? ?  ? ? ? ? ? ? ? ? ? ? ? ? ?   ?      High in-channel flows ? ? ? ? ?  ? ? ? ? ? ? ? ? ? ? ?  ?  ? ?  ? Floodplain flows ? ? ? ? ? ? ? ? ? ?  ? ? ? ? Legend ? very important effect ? important effect  minor effect  ? very important impact ? important impact  minor impact   5 ACKNOWLEDGEMENTS  The authors wish to thank the Queensland Depart-ment of Natural Resources, Mines and Energy (NRM&E) for their support, and members of Water Resource Plan Technical Advisory Panels and other colleagues who have contributed in various ways to the development of water resource planning and en-vironmental flow methodologies in Queensland. This paper does not necessarily represent the views of NRM&E or government policy.  6 REFERENCES  Arthington, A.H. & Pusey, B.J. 2003. Flow restoration and pro-tection in Australian rivers. River Research and Applica-tions 19(5-9): 377 - 395. Brizga, S.O., Arthington, A.H., Choy, S., Craigie, N.M., Ken-nard, M.J., Mackay, S.J., Pusey, B.J. & Werren, G.L. 2002. Benchmarking, a ‘top-down' methodology for assessing en-vironmental flows in Australian Rivers. In Proceedings of International Conference on Environmental Flows for Riv-ers. Cape Town, S. Africa. Bunn, S.E. & Arthington, A.H. 2002. Basic principles and eco-logical consequences of altered flow regimes for aquatic biodiversity. Environmental Management 30(4): 492 – 507. Kapitzke, I.R. 2003. From vision to reality: The crucial role of environmental engineers in achieving sustainability. In Proceedings of the National Environment Conference, Brisbane, 18-20 June 2003. Naiman, R.J., Bunn, S.E., Nilsson, C., Petts, G.E., Pinay, G. & Thompson, L.C. 2002. Legitimizing fluvial ecosystems as users of water: An overview. Environmental Management 30(4): 455 - 467. Poff, N.L., Allan, J.D., Bain, M.B., Karr, J.R., Prestegaard, K.L., Richter, B.D., Sparks, R.E. & Stromberg, J.C. 1997.  The natural flow regime - a paradigm for river conservation and restoration. BioScience 47: 769-784. Sanchez, L.E & Hacking, T. 2002. An approach to linking en-vironmental impact assessment and environmental man-agement systems. Impact Assessment and Project Appraisal 20(1): 25-38. 

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Impact assessment tools for determination of environmental flows in water resource planning

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Impact assessment tools for determination of environmental flows in water resource planning

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