INTRODUCTION TO ENVIRONMENTALFLOW ANALYSIS

Thomas R. PayneCertified Fisheries ProfessionalNormandeau Associates, Inc.

ENVIRONMENTAL FLOW TERMINOLOGY

• Environmental Flow is AKA:– Instream Flow– Ecological Flow– E-flow– Rarely “Minimum” Flow

“Environmental flows are the quantity and timing of water flows required to maintain the components, functions, processes, and resilience of freshwater ecosystems and the goods and services they provide to people.”

HISTORY OF DAMS/RIVER REGULATION

• Egypt – 3000 BC• Roman Empire – 500 BC to 500 AD• Japan – 400 AD to 900 AD• China – 833 AD (still there!)• Great Britain – 1787 AD• River Basin Development – 1930’s

– TVA (US), Columbia River (US), Volga River (USSR), Snowy Mountains (Australia)

HISTORY OF DAMS/RIVER REGULATION

• 1800’s – Ten per year• 1900-1920 – Fifty per year• 1920-1940 – One hundred per year• 1960’s – Five hundred per year• 2000’s – Thousands per year• Current Status of Dams

– 50,000 dams storing more than 1,00,000 m3

– 100,000 dams storing 100,000 m3

TYPES OF ENVIRONMENTAL FLOW METHODS

• Hydrologic– Historic flows

• Hydraulic Rating– River channel characteristics

• Habitat Rating– Mechanistic/Observational

• Individual and Population Modeling– Population Dynamics/Interactions

• Professional Judgment– Economics/Environment

HISTORY OF ENVIRONMENTAL FLOW METHODS

• Late 1800s – United Kingdom– Navigation– Public health– Downstream users– Fisheries protection

• 1900s – United States (State Level)– Appropriation Doctrine– Riparian Doctrine– Reserve Doctrine

APPROACHES IN THE ‘50S AND ‘60S

• Hydrologic– 7Q10 – Lowest seven days over ten years– Q90 – Ninety percent exceedance– Baxter’s percent of mean annual flow

• Hydraulic Rating– Wetted perimeter– Wetted usable width

• Professional Judgment– Managers “decide”, biologists “consult”

ENVIRONMENTAL FLOW BEFORE 1970

• Minimum or Base Flow– Single Threshold– Often applied to summer season– Often resulted in constant minimum flow– Did not consider flow variability

• Result– Habitat Degradation!

• Consequence– Awareness, laws, regulations, methods

APPROACHES IN THE ‘70S

• Research Driven by Consequences• Hydrologic

– Tennant Method Percent of Mean Annual Flow Summer season, winter season, flushing

• Habitat Rating– Washington habitat area method (1972)– Waters’ habitat discharge method (1976)– Physical Habitat Simulation (1978)

EXPLOSION OF APPROACHES

• 1980 – 16 Methods• 1986 – 70 Methods• 2002 – 207 Methods• 2015 – ??? Methods

HYDROLOGIC (31 IN 2002)

• Tennant• Modified Tennant• New England Base Flow• Flow Duration Curves• Texas Method• Basic Flow Method (Spain) • Flow Translucency Approach (Australia)• Range of Variability Approach

HYDRAULIC RATING (23 IN 2002)

• Wetted Perimeter• R-2 Cross• Washington Toe-Width• Oregon Method• Arkansas Method• Colorado Method• Standard Depth Approach• One-Flow Method

HABITAT RATING (58 IN 2002)

• Physical Habitat Simulation (PHABSIM)• River Simulation System (RSS – Norway)• Evaluation of Habitat (EVHA – France)• Computer Aided Simulation Model for

Instream Flow Requirements (CASiMIR)• Riverine Community Habitat Assessment

and Restoration Concept (RCHARC)• River2D• MesoHABSIM

INDIVIDUAL/POPULATION DYNAMICS

• Individual Based Modeling (InSTREAM)• Systems Impact Assessment Model (SIAM)• Salmon Life Cycle Production Model

(SALMOD)• River Invertebrate Prediction and

Classification System (RIVPACS)• SALMOD II

PROFESSIONAL JUDGMENT (16 IN 2002)

• Instream Flow Incremental Methodology• Building Block Methodology (BBM)• Downstream Response to Imposed Flow

Transformations (DRIFT)• Demonstration Flow Approach (DFA)• Expert Panel Assessment Method (EPAM)• Ecological Limits of Hydrologic Alteration

(ELOHA)

SO WHERE ARE WE NOW?

METHODS AND METHODOLOGIES

• Method (tools)A process by which a task is completed.

• Methodology (approaches)A guideline system for solving a problem, with specific components such as phases, tasks, methods, techniques and tools.

WHAT WE’RE MOSTLY DOING

• Methods– Tennant (and modifications)– Demonstration Flow Assessment– MesoHABSIM– Direct Habitat Mapping

• Methodologies– Instream Flow Incremental Methodology (IFIM) and PHABSIM (1D and 2D)– Ecological Limits of Hydrologic Alteration

(ELOHA)– System for Environmental Flow Analysis

(SEFA)

TENNANT (AND MODIFICATIONS)

Percentage of Mean Annual FlowNarrative Description October-March April-SeptemberFlushing or Maximum 200 200Optimum range 60-100 60-100Outstanding 40 60Excellent 30 50Good 20 40Fair or degrading 10 30Poor or minimum 10 10Severe degradation <10 <10

Tennant, D.L. 1975. Instream flow regimens for fish, wildlife, recreation and related environmental resources. USFWS, Billings, MT

TENNANT (AND MODIFICATIONS)

Situation Flow RecommendationMMF < 40% MAF MMFMMF > 40% MAF and40% MMF < 40% MAF

40% MAF

40% MMF > 40% MAF 40% MMFMMF = Mean Monthly FlowMAF = Mean Annual Flow

Tessman, S.A. 1980. Environmental assessment, technical Appendix E, western Dakotas region of South Dakota study. WRRI, Brookings, SD

Others:Estes, C.C. 1984 (Washington), 1998 (Alaska)Trihey, E.W. 1996 (California)Bureau of Land Management. 2006 (Oregon, California)

DEMONSTRATION FLOW ASSESSMENT(Railsback, S.F., and Kadvany, J. 2008)

• Step 1 – Frame the Decision– Clearly define the instream flow decision process

• Step 2 – Develop Conceptual Models of Flow Effects– Develop a shared understanding of important flow

mechanisms

• Step 3 – Select Habitat Metrics– Define the specific measures to be observed and

quantified

• Step 4 – Design and Conduct Field Observations– Observe and quantify or rate the selected habitat metrics

• Step 5 – Analyze Results– Rank alternative flows by the quantity or value of the

metrics

• Step 6 – Negotiate Instream Flows

DEMONSTRATION FLOW ASSESSMENT(Railsback, S.F., and Kadvany, J. 2008)

MesoHABSIM (Parasiewicz, P. 2001)

MesoHABSIM (Parasiewicz, P. 2001)

DIRECT HABITAT MAPPING (McBain & Trush 2013)

Habitat at 150 cfs

DIRECT HABITAT MAPPING

Habitat at 200 cfs

INSTREAM FLOW INCREMENTAL METHODOLOGY(Bovee et al. 1998)

INSTREAM FLOW INCREMENTAL METHODOLOGY(Bovee et al. 1998)

Hydraulics

Microhabitat area per unit length of stream

Channel structure

Microhabitat suitability

criteria

HYDRAULIC HABITAT MODELING (PHABSIM)

HYDRAULIC HABITAT SIMULATION (PHABSIM)

XSEC 1

XSEC 2Hydraulic Model

Velocity: v i

Depth: d i

Substrate: s i

Biological Model

Velocity

Cv

Sv i Sd i Ss iSubstrate

Cs

Physical Habitat Index

Flow

AW

S

1-D MODEL PHYSICAL REPRESENTATION

CROSS SECTION PROFILE AND VELOCITY

2-D MODEL PHYSICAL REPRESENTATION

1-D HABITAT REPRESENTATION

O

O

O

O

OO

OOO

OOO

O

Data points

O

O

OO

O

OO

O

O

OO

O

O

O

Data points

O

2-D HABITAT REPRESENTATION

DVASW @150

0 1 2 3 4

VELOCITY IN FEET PER SECOND

0

1

2

3

DE

PT

H IN

FE

ET

Cover

4

5

6

Depth, Velocity and Attribute Scaled by Suitability and Weight at 150cfsT1 = 15% T2 = 35%

T3 = 35% T4 = 15%

T2

T3

T4

T1

Scaled & weighted data points,3-axis frequency analysis

N=132

Data Points Scaled by Suitability and Weight

PHABSIM 1-D OR 2-D HABITAT INDEX

ECOLOGICAL LIMITS OF HYDROLOGIC ALTERATION (ELOHA)

(Poff et al. 2009)

• ELOHA is “a new framework for developing regional environmental flow standards”

• ELOHA Framework1. Model hydrologic baseline and current

hydrograph2. Classify river segments by ecological

characteristics3. Determine the deviation of current flow from

baseline4. Develop flow alteration-ecological response

relationships

• ELOHA should occur in a consensus context• ELOHA should proceed in an adaptive

management context

ECOLOGICAL LIMITS OF HYDROLOGIC ALTERATION (ELOHA)

(Poff et al. 2009)

QUESTIONS AND DISCUSSION…