Status of Instream Flow Sciencein the Southeastern US

Mary M. Davis, Ph.D., Technical AdvisorSouthern Instream Flow Network

Objectives• Present a scientific framework for establishing

protective instream flow criteria

• Provide an update on advances in instream flow science in SE US

• Strengthen links between mollusk and instream flow scientists in the region

“Hydrologic regimes are the master variables in aquatic ecosystems.” Poff et al. 1997

Alteration of hydrologic regimes is a primary threat to the ecological

integrity of aquatic ecosystems.

Source: USFSCSIROMk2-B2 Scenario

WaterManagement

Who decides how much water needs to stay in the rivers?

IFIM

ELOHA

ESWM

Scientifically credible environmental flow standards are necessary to balance economic pressures.

IFIM

Southern Instream Flow Network

Purpose - To facilitate protective instream flow policies and practices in 15 southern states by providing science-based resources and opening lines of communication.

More information at: www.southeastaquatics.net/programs/sifn/

Southern State Approaches for Determining IF Standards

• Minimum flow threshold– 7Q10 (e.g., AL, LA, MS)– Modified Tennant (e.g., AR, GA, SC)

• Statistically based standards(e.g., FL St Johns WMD, Potomac River Commission)

• Percent of flow approaches(e.g., FL SW Florida and Suwannee River WMDs, TN Presumptive WQ Standard)

Science-based Methods to Determine Instream Flow Needs

• Incremental Flow Method (IFIM)

• Ecologically Sustainable Water Management (ESWM)

• Ecological Limits of Hydrologic Alteration (ELOHA)

Science-based Methods to Determine Instream Flow Needs

• Incremental Flow Method (IFIM)

• Ecologically Sustainable Water Management (ESWM)

• Ecological Limits of Hydrologic Alteration (ELOHA)

Ecological Limits of Hydrologic Alteration (ELOHA)

http://conserveonline.org/workspaces/eloha

(Source: Poff et al. 2010)

Bioti

c ind

icat

or

Hydrologic alteration

Ecological Limits of Hydrologic Alteration (ELOHA)

http://conserveonline.org/workspaces/eloha

(Source: Poff et al. 2010)

Characteristic species

Thriving species

1.0

0.9 -

0.8 -

0.7 -

0.6 -

0.5 -

0.4 -

0.3 -

0.2 -

0.1 -

0.0

Prop

ortio

n of

initi

al fi

sh

popu

latio

n m

etric

Proportion of index flow removed

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Adverse resource impact

Acceptable resource impact

Source: Michigan Groundwater Conservation Advisory Council, 2007

ECO

LOG

ICAL

CO

ND

ITIO

NUse of Ecological Response to

Limit Flow Alteration

0

400

800

1200

1600

2000

0 50 100 150 200 250 300 350

Flow

(cfs

)

10%

8%

13%18%

LFT = 67 cfs

Example Flow PrescriptionPercent of Flow and Seasonality

of allowable cumulative withdrawals

Day of YearSource: Southwest Florida Water Management District MFL Program

Objectives• Present a scientific framework for establishing

protective instream flow criteria

• Provide an update on advances in instream flow science in SE US

• Strengthen links between mollusk and instream flow scientists in the region

• Problem: The limited focus on research and funding for instream flows has resulted in a lack of science to support protective instream flow standards.

• Objective: to highlight research needs and coordinate sources of funding and research to address these needs.

• Goal: to ensure that instream flow research is focused on the needs of water resource managers for scientifically credible and protective state instream flow standards and practices.

Southern Instream Flow Research Agendawww.southeastaquatics.net/programs/sifn

South AtlanticGulf Coast Prairie

Support for theSouthern Instream Flow Research Agenda

Instream Flow Products Under Development for the LCCs

• Hydrologic Foundation • Ecological Databases • Flow-ecology Literature Review• Flow Alteration Assessment • River Classification• Aquatic Conservation Priorities

Integration of Instream Research Agenda ProductsTo Develop Flow-Ecology Relationships

Ecol

ogic

al C

ondi

tion

Hydrologic Alteration

+

+

-

- 0

Hydrologic Models

Ecological ConditionAssessment

Aquatic Conservation Priority Areas

Sources of Flow Alteration

River Classification

Hypothetical Flow-Ecology Relationships

Quantify Flow Alteration

EcologicalMetric

Research Priorities and ValidationEc

olog

ical

Dat

a

Integration of Instream Research Agenda ProductsTo Develop Flow-Ecology Relationships

Ecol

ogic

al C

ondi

tion

Hydrologic Alteration

+

+

-

- 0

Hydrologic Models

Ecological ConditionAssessment

Aquatic Conservation Priority Areas

Sources of Flow Alteration

River Classification

Hypothetical Flow-Ecology Relationships

Quantify Flow Alteration

EcologicalMetric

Research Priorities and ValidationEc

olog

ical

Dat

a

SE River Classification

• Based on existing classifications

• Hierarchical scales for geomorphology, hydrology, and biota

• Principals: John Faustini, USFWS and Chris Konrad, USGS

SARP Flow Alteration Assessment

Approach – Qualitatively assess sources, spatial distribution, and relative magnitude of hydrologic alteration from water consumption, impervious cover, and dams.

Preliminary SE Flow-Ecology Relationships

Source: McManamay et al. 2011

Objectives• Present a scientific framework for establishing

protective instream flow criteria

• Provide an update on advances in instream flow science in SE US

• Strengthen links between mollusk and instream flow scientists in the region

Integration of Instream Research Agenda ProductsTo Develop Flow-Ecology Relationships

Ecol

ogic

al C

ondi

tion

Hydrologic Alteration

+

+

-

- 0

Hydrologic Models

Ecological ConditionAssessment

Aquatic Conservation Priority Areas

Sources of Flow Alteration

River Classification

Hypothetical Flow-Ecology Relationships

Quantify Flow Alteration

EcologicalMetric

Research Priorities and ValidationEc

olog

ical

Dat

a

Priority Instream Flow Research Topic 3:Compile regional aquatic ecology data sets

Multistate Aquatic Resources Information Systemwww.marisdata.org

Integrating State Data into the National Fish Habitat Assessment

MARIS States (2010)

Conclusions:

• Instream flow science is advancing through state, regional, and national efforts.

• Access to biological monitoring data is key to developing scientific flow-ecology relationships.

• Good communication among mollusk scientists and instream flow programs will be key to leveraging limited resources and protection of southern aquatic resources.