Environmental Environmental Flows Rebecca Tharme PhD Riverfutures Nile Eco

Transcription

1 Environmental Flows Rebecca Tharme PhD Riverfutures Photo Rebecca Tharme Nile Eco-VWU Project Ecosystem Services and Environmental Flows Training Course Kampala, Uganda 2-5 Nov 2015

2 Outline 1. Introduction environmental flow concepts and principles 2. Environmental flow methodologies types and application contexts 3. Holistic methodologies for different wetland types best practice and case examples 4. Scaling up basin flow management and decision support tools Photos Rebecca Tharme

3 1. Introduction Environmental Flow Concepts and Principles Photo Rebecca Tharme

4 hydropower diversion industrial cooling irrigation Competing Water Uses municipal navigation drinking

5 The highest global risk Diffusion of weapons of mass destruction Major systematic v financial failure Extreme volatility in ag and energy prices Water supply crisis Chronic fiscal imbalances v Vulnerability to geomagnetic storms Entrenched hd organized crime Cyber attacks Im mpact Likelihood Proliferation of orbital debris Source: WEF Risk assessment 2013

6 Water Stress by International Basin ~20% of basins are heavily depleted Source: Transboundary Dispute Database 2002, Oregon State University

7 Strategic objectives of IWRM 3. Environmental sustainability, to protect the water resource base and associated ecosystems Economic Efficiencyi Equity Environmental Sustainability Management Instruments t Assessment Information Allocation Instruments Enabling Environment Policies Legislation Institutional Framework Central - Local River Basin Public - Private (GWP 2000) Balance water for livelihood and water as a resource

8 Environmental Flows Nested Within Integrated t Water Resources Management (van der Zaag and Savenije 2014)

9 Hydrological Alteration is a Primary Driver of Ecosystem Change Loss ofriver floodplain connectivity Presence of physical barriers Photo Rebecca Tharme Altered flow pattern andtiming 8000 Green River Below Flaming Gorge Flow (cfs) October November December January February March April May June July August September Pre-dam Post-dam

10 What alters hydrology? Dams Withdrawals Land-Use Change Climate Change

11 Colorado River Hoover Dam All-American Canal and Colorado River Aqueduct Flaming Gorge and Glen Canyon Dams Central Arizona Project

12 Groundwater Withdrawal Resulting in Streamflow Depletion CHINA Fuyang Basin, North China Plain (Kendy 2002)

13 On the Decline Aquatic biodiversity and Ecosystem Integrity Photos Rebecca Tharme 76% decrease in populations of freshwater dependent spp. since 1970 (WWF 2014) Major loss of freeflowing rivers 50% of length of all rivers with discharge > 1000 m 3 s 1 impacted (Lehner et al. 2011) Source: WWF 2014

14 Detrimental Impacts on Ecosystem Services Livelihoods and Human Well being Provisioning (fish, freshwater) Regulating (pollution control, climate regulation) Supporting (sediment transport, nutrient cycling) Cultural l( (sacred sites, recreation) Photo Rebecca Tharme Photo Eric Baran Photo CFE Mexico Richter et al. 2010

15 Future Impacts Expected eg e.g. Hydropower Expansion (Opperman et al. 2015)

16 View Aquatic Ecosystem as a Social Ecological System Key ecological attributes Flow is a critical variable Hydrograph components Magnitude, timing, duration, frequency, rate of change, variability Flow events with specific functions that support ecological integrity and ecosystem services for people Functional network in basin Coupled natural human system

17 What are environmental flows?..or instream flows or ecological flows..or o sustainable ab flows? or environmental e water requirements The Brisbane Declaration

18 Environmental Flow The quantity, timing, and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods lih and well being that depend don these ecosystems. (Brisbane Declaration 2007) Photo Rebecca Tharme

19 The Natural Flow Paradigm The full range of natural intra- and inter-annual variation in hydrologic regimes, and associated characteristics of timing, duration, frequency, and rate of change, are critical in sustaining the full native biodiversity and integrity of aquatic ecosystems. (Richter et al. 1997)

20 Environmental Flows Management Tool for Ecosystem Integrity and Biodiversity it Conservation (Karr 1991; Silk & Ciruna 2004)

21 Environmental Flows - Management Tool for Delivery of Ecosystem Services for Livelihoods 1. Provisioning (e.g. fish, high quality freshwater) 2. Regulating (e.g. pollution control, climate regulation) 3. Supporting (e.g. nutrient cycling, biodiversity) 4. Cultural (e.g. sacred sites, recreation) (Millennium Ecosystem Assessment 2005)

22 Environmental Flows: Water for People vs Ecosystems? Engineering g Era water only for people p Early Conservation water for single iconic species (fish), reductionistic reductionistic i i Ecological Era water for whole ecosystems, holistic ( but how much is needed?) Social ecological Era water for people and ecosystems, economic optimization of tradeoffs (e.g. ecosystem services) (Poff and Matthews 2013 COSUST)

23 Framework for Ecologically Sustainable Water Management Define Ecosystem Goals

24 Hierarchical Application of Environmental Flows Landscape/regional level national planning estimates, multiple projects, large basins, basin clusters, low priority systems Project/site level single river basin, river reaches, project site, high priority system with allocation tradeoffs

25 Site or project-level environmental flow determination Limited Resources available Extensive Moderate Level 1: Hydrologic analysis Level 2: Expert-panel driven comprehensive Level 3: Field studies and modeling Level 4: Adaptive refinement

26 Establishing eflows at landscape / regional scale Ecological Limits of Hydrologic Alteration (ELOHA) SCIENTIFIC PROCESS Step 1. Hydrologic Foundation Baseline Hd Hydrographs Hydrologic Model and Stream Gauges Developed Hydrographs Step 2. Stream Classification Stream Hydrologic Classification Step 3. Flow Alteration Degree of Hydrologic Alteration Geomorphic Subclassification Hydrologic Alteration by River Type Monitoring Step 4. Flow Ecology Relationships Flow Ecology Hypotheses Ecological Data and Indices Flow Alteration Ecological Response Relationships by River Type SOCIAL PROCESS Implementation Adaptive Adjustments Step 5. Social Balancing & Standards Environmental Flow Standards Acceptable Ecological Conditions Societal Values and Management Needs Rebecca Tharme

27 (Lytle & Poff (2004) The Hydrologic Basis of Eflows

28 Hydrological Regime Characteristics ti Natural within- and between-year flow variability Magnitude Frequency Duration Timing Rate of change Flow components Flow components Extreme low flows Low flows High flow pulses Small floods Large floods

29 River Functions and the Natural Flow Regime Principle 3 Lateral connectivity Longitudinal connectivity Principle 1 Channel form Habitat complexity Patch disturbance Biotic diversity Discha arge Principle 2 Life history patterns Flowers& seeds Growth strategy Time Bunn and Arthington 2002 Principle 4 Natural regime discourages invasions?

30 Creates backwater habitat & spawning bars (cfs) Flow Migration cue Floodplain inundation (stock up on reserves before spawning migration) Stable baseflow (overwinter in backwater habitat) Spawning Spawning habitat maintenance Hatch & larval drift to backwater habitat Fall Winter Time Spring Summer

31 Ecohydrological model (e.g. Trinity River, USA)

32 Identify ecologically relevant flow events Mimic the natural spatiotemporal flow pattern (Tharme and King 1998)

33 Stages in Environmental Flow Assessment Floods Environmental Flow Recommendation Savannah River, below Thurmond Dam (River-Floodplain) 50,000-70,000 cfs; 2 weeks, avg every 2 yrs Maintain channel habitats Create floodplain topographic relief Provide fish access to the floodplain control invasive species Maintain wetlands and fill oxbows and sloughs Enhance nutrient cycling & improve water clarity Disperse tree seeds High Flow Pulses >30,000 cfs;5 pulses, >2 days with 2 events of 2 week duration (March and early April) 20,000-40,000 cfs; 2-3 days, 1/month Provide predator-free habitat for birds Disperse tree seeds Transport fish larvae Flush woody debris from floodplain to channel Floodplain access for fish Fish passage past NSBLD Floods: Maintain wetlands and fill <13,000 cfs; 3 successive years, every years Floodplain tree recruitment oxbows and sloughs 8,000-12,000 cfs; Exchange water with oxbows Low Flows Key Wet Year Avg Year Dry Year >8,000 cfs Larval drift for pelagic spawners <5,000 cfs Adequate floodplain drainage Create shallow water habitat for small-bodied fish 3,000 cfs; 3 successive years every years Floodplain tree recruitment JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

34 Upper Mississippi Basin Catchment Protection (Protected areas) Areas of Freshwater Biodiversity Significance Agriculture Best Management Practices Flow Management For Transportation & Biodiversity Water Use Certification

35 Setting Objectives for Ecosystem Condition: AStakeholde Stakeholder Process Pocess Total development No development Over-utilize water resources Negligible water use Highly degraded river Un-impacted river

36 Resource classification system Stream Ecological Goal Classes Maine, USA Class AA Outstanding natural resource for preservation Class A Habitat for fish and other aquatic life is natural Class B Habitat for fish and other aquatic life is unimpaired Class C Habitat for fish and other aquatic life exists % OF LINEAR MILES OF STATUTORY CLASSIFICATIONS Class AA = 6% Class A = 45% Class B = 47% Tom Danielson, Maine DEP Class C = 2%

37 Vision and Objectives Murray Darling Basin Environmental Watering Objectives Hierarchy

38 Thanks Dr Rebecca Tharme Riverfutures Photo Rebec