River Health. Healthy river flow is variable

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River Health River health ranges from poor to good As defined by people, measured scientifically State of river health depends on: Water quality Sediment

1 River Health River health ranges from poor to good As defined by people, measured scientifically State of river health depends on: Water quality Sediment transport Riparian vegetation Connectivity Management of human pressures, e.g. Fishing Gravel extraction River flows (hydrology) Healthy river flow is variable 2

Principle 3 lateral connectivity longitudinal connectivity access to floodplains spates Principle 1 channel

reproductive triggers Principle 2 Life history patterns spawning recruitment seasonality predictability stable

principles and ecological consequences of altered flow regimes for aquatic biodiversity.

2 Principle 3 lateral connectivity longitudinal connectivity access to floodplains spates Principle 1 channel form habitat complexity bio c diversity patch disturbance Discharge dispersal triggers variability reproductive triggers Principle 2 Life history patterns spawning recruitment seasonality predictability stable baseflows drought Time Principle 4 natural regime discourages invasions Bunn SE and Arthington AH (2002) Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity. Environmental Management 30: River banks and bed are naturally dynamic Interaction of flow and channel form creates hydraulic habitat 3

3 Fish behaviour may be influenced by flow events Pulses and floods allow up and downstream movement and floodplain access 4

ecosystems (The Brisbane Declaration 2007) 1 1.

4 Variable flows are less favourable to invasive pest species Definition the quality, quantity, and timing of water flows required to maintain thecomponents, functions, processes, and resilience of aquatic ecosystems, and the human livelihoods and well being that depend on these ecosystems (The Brisbane Declaration 2007) 1 1. Proclaimed at the 10 th International River Symposium and International Environmental Flows Conference, held in Brisbane, Australia, on 3 6 September ganizations_final.pdf 5

5 What do environmental flows protect? components, functions, processes, and resilience of aquatic ecosystems Ecological assets What do environmental flows protect? the human livelihoods and well being that depend on these ecosystems Ecological assets 6

6 Other uses of rivers that do not require good ecological health (prefer steady flow) How to assess flow needs? The ecological environment will respond to all of the flows in a river Flow regime that will maintain the ecological health of assets in the condition desired and agreed by society 7

7 Main steps 1. Define the ecological assets 2. Agree on the desired condition of the assets 3. Set ecological objectives (targets) 4. Scientific work to determine the flows neededto meet the objectives 5. Determine the impacts on other users 6. Undergo trade off and negotiation Scientific approaches Tharme (2003) 207 methods in 44 countries ti e.g. IFIM, BBM, DRIFT, ELOHA, FLOWS, RVA, EPAN, FPM, FLOWRESM, FEM, etc. Methods, Approaches, Frameworks Prescriptive, Interactive Bottom up, Top down Hydraulic index, Hydraulic rating, Habitat simulation, Holistic 8

water does the river need? Then negotiate with other users What is the best way to deliver the given volume?

8 How the process often works Rapid/cheap/easy Need a quick answer Hydrological method Need a politically acceptable answer Management or political decision Slow/expensive/difficult For good river health, how much water does the river need? Then negotiate with other users What is the best way to deliver the given volume? Usually begin with a suboptimal allocation Social decision Scientific problem People Environment More/less flow River health 9

9 Percent of flow (Tennant) Description of flows Percent of mean annual flow Dry season Wet season Flushing or maximum 200 % of mean annual flow Optimum range 60 80% of mean annual flow Outstanding 40% 60% Excellent 30% 50% Good 20% 40% Fair or degrading 10% 30% Poor or minimum 10% 10% Severe degradation 0 10% of mean annual flow Based on biological data from 11 streams in Montana, Wyoming and Nebraska (1970s) Scaling the natural hydrological regime Flow Health ( 9 flow parameters with ecological relevance Low flows, high flows, sequence of flows Scores the hydrology 0 (no flow) to 1 (natural flow) Stth Set the desired dflow Health score (0 1) A flow regime is derived to meet the score, based on the natural flow pattern 10

Detailed holistic assessment process 1 Select representative reaches and sites 2 Identify ecological assets

for each asset and process 5 Hydraulic modeling and hydrological analysis 6 Develop preferred environmental flows

under the preferred and alternative flow options (then make a decision) Characterise the ecological assets Criterion

10 Detailed holistic assessment process 1 Select representative reaches and sites 2 Identify ecological assets (environmental survey) 3 Develop conceptual models (between flow and ecological assets) 4 Set management objectives for each asset and process 5 Hydraulic modeling and hydrological analysis 6 Develop preferred environmental flows rules (ideal) 7 Develop alternative environmental flows rules (options) 8 Model the water resources availability under the preferred and alternative flow options (then make a decision) Characterise the ecological assets Criterion Adult Juvenile Spawning Depth (m) > Velocity (m/s) <0.3 Season All year All year April to June 11

Conceptual models Bankfull and overbank flows Low flows Flow pulses Maintain water depth and water quality in pools Maintain longitudinal connectivity for movement Maintain biofilms; input carbon

11 Conceptual models Bankfull and overbank flows Low flows Flow pulses Maintain water depth and water quality in pools Maintain longitudinal connectivity for movement Maintain biofilms; input carbon from stream margins Scour pools and banks; mobilise bed material Flush estuary with fresh water; supply fine sediment Maintain estuarine salinity gradient Promote growth of macrophytes & algae; detritus Inundate fish spawning areas in Zhuxi and Yong anxi Maintain habitat for invertebrates & amphibians Check vegetation encroachment into channel Maintain water depth in backwaters Transport eggs and larvae downstream Maintain physical habitat Opportunities for reproduction Supply food resources Maintain fisheries One of the assets Gippel, C.J., Bond, N.R., James, C. and Wang, X. 2009a. An asset based, holistic, environmental flows assessment approach. Water Resources Development 25(2): Hydraulic modelling Depth (m) Velocity (m/s) Distribution of depth and velocity at 1,000 m 3 /s 12

12 Recommended flow regimes Flow component Low flow High flow Low flow pulse Timing Months Flow (m 3 /s) Low season High season Low season Frequency (events/yr) Duration (days) Rise and fall (max m 3 /s per day) Objective Jan Dec XX Continuous XX XX/YY a, b, Jan Dec XX Continuous XX XX/YY a, b, Jan Dec XX X XX XX/YY a, b, High flow Spawning Jan Dec XX X XX XX/YY a, b, pulse period Bankfull Overbank High season High season Jan Dec XX X XX XX/YY a, b, Jan Dec XX X XX XX/YY a, b, Model water availability/impacts Hypothetical reservoir (not proposed) Yong anxi L3 L2 Zhuxi L1 engxi Shife L4 L5 Lingjiang Linhai Yongningxi Jiaojiang Taizhou L6 Bay Shisandu Reservoir (proposed) Transfer pipe (proposed) Zhuxi Reservoir (proposed) Changtan Reservoir (existing) Gippel, C.J., Cosier, M., Markar, S. and Liu, C. 2009b. Balancing environmental flow needs and water supply reliability. Water Resources Development 25(2):

Environmental Flow Regimes. Joe Trungale s presentation to the Science Advisory Committee March 4, 2009

Environmental Flow Regimes. Joe Trungale s presentation to the Science Advisory Committee March 4, 2009 Overlays to Hydrology-Based Environmental Flow Regimes Joe Trungale s presentation to the Science Advisory Committee March 4, 2009 Overlays - Definition Application of analysis to validate or refine flow