Environmental Flowsecological principles, applications,

and lessons from New Mexico

Maceo C. MartinetMarilyn Myers

W. Jason Remshardt

U.S. Fish and Wildlife ServiceAlbuquerque, NM

American Fisheries Society Western Division Conference 2009

Environmental Flows: definition

Describe the quantity, timing, and qualityof water flows required to sustain

freshwater ecosystems

and the human livelihoods and well-being of those that depend on these ecosystems*

*The Brisbane Declaration, 2007: > 750 scientists from >50 countries

Environmental Flows: Principle I

• The natural flow regime is a major force shaping the physical habitat biotic

composition

Bunn and Arthington 2002, Naiman et al. 2002, Arthington et al. 2006, Richter et al., 2003, Poff et al., 1997

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• Redistributing sediment, debris, nutrients

• Channel geomorphology

• Habitat patches disturbance

complexity of runs, riffles, pools, back channels….

Base flows can affect availability of habitat and connectivity between patches

Environmental Flows: Principle II• Aquatic and riparian species have adapted

to natural flow regimes (eg. variability and seasonality)

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CPUE vs DischargeSeasonal pattern life history patternsCottonwood seed dispersal

coincides with receding floodwater

Jul & AugBunn and Arthington 2002, Naiman et al. 2002, Poff et al., 1997

Environmental Flows: Principle III

• Maintain longitudinal and lateral hydrologic connectivity

Vannote et al, 1980, Bunn and Arthington 2002, Naiman et al. 2002Time

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• Overbank flooding

• Upstream ↔ downstream

Environmental Flows: Applications

• 1996 - South Africa’s New Constitution– protection of env. flows are fundamental to healthy

environment healthy society

• 2007 - Maine water use standards– Protection based on natural variations in flow

• 2007 – Montana legislature– Protecting env. flows from groundwater withdrawals

– 2 water bodies are connected

Tharme 2003, Smith 2008

Environmental Flows: lessons from New Mexico

Gila

Rio Grande

San Juan

Pecos

Gila River (Gila, NM) Natural Flow Regime (72-yr record)

• Plans to divert ~ 14,000 acre-ft per year for SW New Mexico• NM Governor and water officials embraced collaborative, science-

based approach • Preliminary environmental flow analysis low flow and small

floods likely altered, spring and winter monthsHaney 2006

Pecos

• Water management ≠ natural flow regime

• Block release flows irrigators

• Different hydrograph if we take ecosystem into account

Pecos bluntnose shiner, interior least tern

San Juan

Pre-dam High spring flows, low base flows (lots of variability)

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1,000

2,000

3,000

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5,000

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9,000

30-S ep 19-Nov 8-J an 27-F eb 17-Apr 6-J un 26-J ul 14-S ep 3-Nov

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cfs

P re-Navajo Dam 1929-61

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1,000

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9,000

30-S ep 19-Nov 8-J an 27-F eb 17-Apr 6-J un 26-J ul 14-S ep 3-Nov

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P re Navajo Dam 1929-61 P os t dam 1962-1991

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1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

30-S ep 19-Nov 8-J an 27-F eb 17-Apr 6-J un 26-J ul 14-S ep 3-Nov

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P re-dam 1929-61 P os t dam 1962-1991 R es earc h P eriod 1993-2008

Post-dam native fish decline

Colorado pikeminnow (listed in 1967) razorback sucker (listed in 1991)

Research Period natural flow regime key to species recovery

- Higher peak flows = build and clean fish habitat (eg. cobble bars, backwaters)- Lower base flows = optimize availability of habitat (eg. backwaters)- Flow recommendations using statistical variability of natural

hydrograph (eg. flows > 5,000 cfs at least 21 days, >10,000 cfs 5 days or more)

Rio Grande

- Quantity and variability of annual peak flows ↓- Sediment starved and stable river bank incised

channel, little overbank flooding

Integrating Environmental Flows

• Progress in how to maintain healthy water ways application

• climate change living within ecological limits

• Challenge help public understand and define sustainability thresholds

Postel and Richter, 2003