Texas Instream Flow Studies:Texas Instream Flow Studies:Technical OverviewTechnical Overview

Wendy Gordon, Ph.D.Wendy Gordon, Ph.D.Texas Commission on Environmental QualityTexas Commission on Environmental Quality

October 2006October 2006

The Context of Instream Flow The Context of Instream Flow ScienceScience

Acknowledgment of the importance of Acknowledgment of the importance of water flowing in a stream to fish, water flowing in a stream to fish, wildlife and peoplewildlife and people

Acknowledgment that competing uses Acknowledgment that competing uses of water have resulted in degraded river of water have resulted in degraded river ecosystemsecosystems

The challenge of developing methods The challenge of developing methods to quantify environmental or instream to quantify environmental or instream flow needsflow needs

Paradigm Shift in Instream Paradigm Shift in Instream Flow RecommendationsFlow Recommendations

1950s-70s development of first 1950s-70s development of first instream flow methods yielding instream flow methods yielding single single minimum flowminimum flow

Growing recognition of role of natural Growing recognition of role of natural flow regimes: flow regimes: magnitude, duration, magnitude, duration, frequency, timing, rate of changefrequency, timing, rate of change

Recent shift to consideration of entire Recent shift to consideration of entire flow regime: flow regime: subsistence, base, high subsistence, base, high flow pulses, overbankflow pulses, overbank

Senate Bill 2Senate Bill 2

Establish data collection and evaluation Establish data collection and evaluation programprogram

Determine flow conditions necessary toDetermine flow conditions necessary tosupport a support a sound ecological environmentsound ecological environmentin Texas rivers and streamsin Texas rivers and streams

Complete priority studies by December Complete priority studies by December 31, 201031, 2010

In 2001, the Texas Legislature directed In 2001, the Texas Legislature directed TCEQ, TPWD & TWDB to:TCEQ, TPWD & TWDB to:

“…“…conduct studies and analyses conduct studies and analyses to determine appropriate to determine appropriate

methodologies for determining methodologies for determining flow conditions in the state’s flow conditions in the state’s

rivers and streams necessary to rivers and streams necessary to support a sound ecological support a sound ecological

environment.”environment.”

Legislative DirectiveLegislative Directive

State drafted its State drafted its methodologymethodology

State contracted State contracted with NRC to peer with NRC to peer review programreview program

Members included Members included TNC’s Brian RichterTNC’s Brian Richter

Report published in Report published in 20052005

(recommended by National Research Council 2005)(recommended by National Research Council 2005)

Instream Flow ComponentsInstream Flow Components

ComponentComponent HydrologyHydrology GeomorphologyGeomorphology BiologyBiology Water QualityWater Quality

Subsistence Subsistence FlowsFlows

Infrequent,Infrequent,low flowslow flows

Increased deposition of Increased deposition of fine & organic particlesfine & organic particles

•Restricted aquatic Restricted aquatic habitathabitat•Limited connectivityLimited connectivity

•Elevated tempElevated temp•Reduced levels ofReduced levels ofDODO

Base FlowsBase Flows Normal Normal flow flow conditions conditions with with variabilityvariability

•Maintain soil moisture & Maintain soil moisture & groundwater table groundwater table•Maintain diversity of Maintain diversity of habitatshabitats

•Suitable aquatic habitat Suitable aquatic habitat •Connectivity along Connectivity along channel corridorchannel corridor

Suitable in-channel Suitable in-channel water qualitywater quality

High Flow High Flow PulsesPulses

In-channel,In-channel,short short duration,duration,high flowshigh flows

•Maintain channel & Maintain channel & substrate characteristicssubstrate characteristics•Prevent encroachment of Prevent encroachment of riparian vegetationriparian vegetation

•Recruitment events for Recruitment events for organismsorganisms•Connectivity to near- Connectivity to near- channel water bodieschannel water bodies

Restore in-channel Restore in-channel water quality after water quality after prolonged low-prolonged low-flowflow

Overbank Overbank FlowsFlows

Infrequent,Infrequent,high flows high flows that exceed that exceed normal normal channelchannel

•Floodplain maintenanceFloodplain maintenance•Lateral channel movementLateral channel movement•New habitat constructionNew habitat construction•Flush organic material Flush organic material into channelinto channel•Deposit nutrients in Deposit nutrients in floodplainfloodplain

•Life phase cues forLife phase cues fororganismsorganisms•Riparian recruitment & Riparian recruitment & maintenancemaintenance•Connectivity with Connectivity with floodplainfloodplain

Restore water Restore water quality in quality in floodplainfloodplainwater bodieswater bodies

Flow Regime FunctionsFlow Regime Functions

Statewide Goal: Support a Sound Statewide Goal: Support a Sound Ecological EnvironmentEcological Environment

““A resilient, functioning ecosystem A resilient, functioning ecosystem characterized by intact, natural characterized by intact, natural

processes, and a balanced, integrated, processes, and a balanced, integrated, and adaptive community of organisms and adaptive community of organisms

comparable to that of the natural habitat comparable to that of the natural habitat of a region."of a region."

River BasinsRiver Basins

Biotic ProvincesBiotic Provinces

Ecosystem DiversityEcosystem Diversity

Summary of the State of KnowledgeSummary of the State of Knowledge

Develop Conceptual Model &Develop Conceptual Model &

Tie Knowledge to Flow ComponentsTie Knowledge to Flow Components

Identify and Prioritize Knowledge GapsIdentify and Prioritize Knowledge Gaps

Develop Prioritized Research AgendaDevelop Prioritized Research Agenda

Interdisciplinary EffortInterdisciplinary Effort

Study DesignStudy Design

Data Integration to Generate Flow Conditions

Reconnaissance andInformation Evaluation

Study Design

Multidisciplinary Data Collectionand Evaluation

Goal Development Consistent with Sound Ecological Environment

Stakeholder Input

Peer Review

Draft Study Report

Final Study Report

Next Steps: Implementation, Monitoring, and Adaptive Management

Stakeholder Input

Stakeholder Input

Stakeholder Input

Stakeholder Input

Peer Review

Peer ReviewSB2 ends

Post SB2

Steps in TIFP Sub-Basin StudiesSteps in TIFP Sub-Basin Studies

Temporal and keyword queryTemporal and keyword queryfish studies conducted 1950s-90sfish studies conducted 1950s-90s

Simple Simple Conceptual ModelConceptual Model

Base FlowsSubsistence Flows Overbank FlowsHigh Flow Pulses

Conserve biologicalfunction

Conserve biological /habitat diversity and

water quality

Life history /geomorphic processes

Floodplain maintenance

•Moisture and nutrients to floodplain•Riparian recruitment

•Water quality tolerances met•Key habitat thresholds maintained

•Habitat for flow dependent species•Bank storage/moisture•Suitable temperatures / dissolved oxygen

•Fish spawning cues•Maintain channel•Sediment/nutrient transport

Sound Ecological Environment

Study DesignStudy Design

Incorporate conceptual model of system Incorporate conceptual model of system Determine geographic scope of studyDetermine geographic scope of study Prioritize data deficienciesPrioritize data deficiencies Develop basin-specific interdisciplinary Develop basin-specific interdisciplinary

study plan study plan

Data Integration to Generate Flow Conditions

Reconnaissance andInformation Evaluation

Study Design

Multidisciplinary Data Collectionand Evaluation

Goal Development Consistent with Sound Ecological Environment

Stakeholder Input

Peer Review

Draft Study Report

Final Study Report

Next Steps: Implementation, Monitoring, and Adaptive Management

Stakeholder Input

Stakeholder Input

Stakeholder Input

Stakeholder Input

Peer Review

Peer ReviewSB2 ends

Post SB2

Steps in TIFP Sub-Basin StudiesSteps in TIFP Sub-Basin Studies

Primary DisciplinesPrimary Disciplines

Hydrology & HydraulicsHydrology & HydraulicsPhysical Processes Physical Processes (Geomorphology)(Geomorphology)

BiologyBiology Water QualityWater Quality

ConnectivityConnectivity

BiologyBiology

Examine integrity of biological Examine integrity of biological communitycommunity

Examine biodiversity within Examine biodiversity within ecosystemecosystem

Assess habitat-flow relationshipsAssess habitat-flow relationships

BiologyBiology

Habitat DiversityHabitat DiversityBiodiversityBiodiversity

Water QualityWater Quality

Identify constituents of concernIdentify constituents of concern Assess low flow-water quality Assess low flow-water quality

relationshiprelationship Conduct water quality modeling studiesConduct water quality modeling studies

Water QualityWater Quality

Dissolved oxygenDissolved oxygen pHpH TemperatureTemperature Total dissolved solidsTotal dissolved solids Turbidity/clarityTurbidity/clarity NutrientsNutrients

Hydrology & HydraulicsHydrology & Hydraulics

Calculate flow statisticsCalculate flow statistics Describe Wet, Normal, & Dry conditionsDescribe Wet, Normal, & Dry conditions Model hydraulic characteristicsModel hydraulic characteristics

Hydrology and HydraulicsHydrology and Hydraulics

Brazos River at Richmond 08114000

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

Feb

-04

Mar

-04

Apr

-04

May

-04

May

-04

Jun-

04

Jul-0

4

Aug

-04

Sep

-04

Oct

-04

Nov

-04

Dec

-04

Jan-

05

Date

Flo

w (

cfs)

Hydraulic and Habitat ModelingHydraulic and Habitat Modeling

Habitat changes with flowHabitat changes with flow

Habitat Habitat ModelingModeling

Habitat Habitat ModelingModeling

Physical Processes Physical Processes (Geomorphology)(Geomorphology)

Assess bedforms, banks, and floodplainsAssess bedforms, banks, and floodplains Assess active floodplain and channel Assess active floodplain and channel

processesprocesses Assess channel adjusting and overbank Assess channel adjusting and overbank

flow behaviorflow behavior Develop sediment budgetsDevelop sediment budgets Identify habitat featuresIdentify habitat features

River Styles HierarchyRiver Styles HierarchyWatershedWatershed Watershed area determined by drainage divide. Determines Watershed area determined by drainage divide. Determines

the boundary conditions within which rivers operate.the boundary conditions within which rivers operate.

Geomorphic UnitGeomorphic Unit Instream and floodplain landforms (pools, bars, levees, Instream and floodplain landforms (pools, bars, levees, backwaters, etc.) that reflect distinct form-process associations. backwaters, etc.) that reflect distinct form-process associations.

River StyleRiver Style Length of channel with a characteristic assemblage of Length of channel with a characteristic assemblage of geomorphic units. geomorphic units.

Landscape UnitLandscape Unit Topographic unit determined on the basis of local relief, Topographic unit determined on the basis of local relief, valley slope and morphology. Defines the valley-setting.valley slope and morphology. Defines the valley-setting.

Hydraulic UnitHydraulic Unit Uniform patches of flow and substrate material within a Uniform patches of flow and substrate material within a geomorphic unit. geomorphic unit.

MicrohabitatMicrohabitat Individual elements (e.g., logs, rocks, gravel patches) within a Individual elements (e.g., logs, rocks, gravel patches) within a stream. stream.

Kilometers0 100 200 300 400

Watershed Namoi River Basin, New South Wales

Watershed

LandscapeUnit

Namoi River Basin, New South Wales

Kilometers0 1005025

Legend – Landscape Units

Rugged metasediments

Rugged volcanics

Uplands

Pillaga outwash

Pillaga

Mid to lower Peel

Lowland plains

Liverpool plains

Middle NamoiSub-basin

Watershed

LandscapeUnit

River Style

Kilometers0 5025

Channel and Valley Width

Channel Slope

Valley Cross Section

Planform

Uplands Escarpment Base of the Escarpment Rounded Foothills Lowland Plain

LandscapeUnit

River StyleHead-water

GorgeFan

Cut & Fill (Incised)

Cut & Fill (Intact)

Vertically Accreated Floodplain

ThroughputFloodout

Transfer

Floodplain Accumulation

GeomorphicUnit

HydraulicUnit

Microhabitat

Riffle

Floodplain

Run

Pool

Bar

Secondary Channel

Pool

BackwaterTrailing

Vegetation

Submerged Macrophyte

Cobbles

Large Woody Debris

BouldersSand

Leaf Pack

Rippled flow on cobbles

Smooth surface flow on cobbles

Smooth surface flow on cobbles/sand

Barely perceptible flow on sand/boulders

Barely perceptible flow on sand

ConnectivityConnectivity

Hydrologic connectivity Hydrologic connectivity Upstream to downUpstream to down Channel to floodplainChannel to floodplain

Groundwater/surface water interactionsGroundwater/surface water interactions

Data Integration to Generate Flow Conditions

Reconnaissance andInformation Evaluation

Study Design

Multidisciplinary Data Collectionand Evaluation

Goal Development Consistent with Sound Ecological Environment

Stakeholder Input

Peer Review

Draft Study Report

Final Study Report

Next Steps: Implementation, Monitoring, and Adaptive Management

Stakeholder Input

Stakeholder Input

Stakeholder Input

Stakeholder Input

Peer Review

Peer ReviewSB2 ends

Post SB2

Steps in TIFP Sub-Basin StudiesSteps in TIFP Sub-Basin Studies

Identify Biological Considerations

Calculate Low Flow Statistics

Identify Water Quality Constituents of Concern

Conduct Water Quality Modeling Studies

Assess Low Flow - Water Quality Relationship

Subsistence Flows

Other Biological Considerations

Primary Discipline Hydrology/Hydraulics Biology Geomorphology Water Quality

Subsistence FlowsSubsistence Flows

Assess Bedform and Banks

Model Hydraulic Characteristics in Relation to Flow

Determine Habitat Criteria

Describe Wet, Normal, and Dry Years

Calculate Base Flow Statistics

Collect Biological Data

Assess Habitat-Flow Relationships,

including Diversity

Consider Water Quality Issues

Consider Biological and Riparian Issues

Base Flows

Identify Biological Issues and Key Species

Base FlowsBase Flows

Primary Discipline Hydrology/Hydraulics Biology Geomorphology Water Quality

Assess Active Channel Processes

Develop Sediment Budgets

Assess Channel Adjusting Flow Behavior

High Flow Pulses

Calculate High Flow Statistics

Consider Water Quality Issues

Consider Biological Issues

Describe Significant Habitat Conditions

High Flow PulsesHigh Flow Pulses

Primary Discipline Hydrology/Hydraulics Biology Geomorphology Water Quality

Assess Overbank Flow Behavior

Overbank Flows

Model Extent of Flood Events

Conduct Riparian Studies

Consider Biological Issues

Estimate Riparian Requirements

Consider Water Quality Issues

Calculate Flood Frequency Statistics

Assess Active Floodplain and Channel Processes

Overbank FlowsOverbank Flows

Primary Discipline Hydrology/Hydraulics Biology Geomorphology Water Quality

Integration to GenerateIntegration to Generatea Flow Regimea Flow Regime

Integration of Flow ComponentsIntegration of Flow Components

OverbankFlows

High FlowPulses

BaseFlows

SubsistenceFlows

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

35 - 55 cfsMaintain water quality (35 cfs) and key habitats in May (55 cfs)

40-50 cfsFish habitat

90-100 cfsFish habitat

150-300 cfsSpring spawning

100-150 cfsFish habitat

300-450 cfsmaintain biodiversity and longitudinal connectivity

700-1500 cfs for 2-3 days2-3 X per year every year

Sediment transportLateral connectivity

Fish spawning

1800 cfs for 2 days1 X per yr every other year“Big River fish” spawningbetween Jul 15 - Aug 15

4,000-10,000 cfs for 2-3 daysOnce every 3-5 yearsChannel Maintenance

Riparian Connectivity, Seed dispersalFlooplain habitat

Wet year Average year Dry year

Projects Funded for SB2Projects Funded for SB2 Field-Based Mapping in support of a Geomorphic Analysis of the Field-Based Mapping in support of a Geomorphic Analysis of the

Lower San Antonio River Subbasin Lower San Antonio River Subbasin GIS-Based Geomorphic Analysis of the Lower San Antonio River GIS-Based Geomorphic Analysis of the Lower San Antonio River

SubbasinSubbasin Field-Based Analysis in support of a Geomorphic Assessment of the Field-Based Analysis in support of a Geomorphic Assessment of the

Brazos & Navasota River SubbasinBrazos & Navasota River Subbasin Geomorphic Equilibrium in Southeast Texas RiversGeomorphic Equilibrium in Southeast Texas Rivers Distributional Survey and Habitat Utilization of Freshwater MusselsDistributional Survey and Habitat Utilization of Freshwater Mussels Developing a Large Woody Debris Budget for the Sabine River, TXDeveloping a Large Woody Debris Budget for the Sabine River, TX Historical Zoogeography And Abundance Of Fishes In Two Texas River Historical Zoogeography And Abundance Of Fishes In Two Texas River

Basins With An Annotated Species ListBasins With An Annotated Species List Assessment of Hydrologic Alteration SoftwareAssessment of Hydrologic Alteration Software Geomorphic Studies of the Lower Brazos and Navasota RiversGeomorphic Studies of the Lower Brazos and Navasota Rivers Analysis of Existing Biological DataAnalysis of Existing Biological Data Biological Sampling on the Lower Brazos River, Sabine River, and San Biological Sampling on the Lower Brazos River, Sabine River, and San

Antonio River (3 separate contracts)Antonio River (3 separate contracts) Stakeholder ProcessStakeholder Process

Additional Questions & CommentsAdditional Questions & Comments

Contact:Contact: Wendy Gordon, TCEQ, 512-239-4174Wendy Gordon, TCEQ, 512-239-4174

wgordon@tceq.state.tx.uswgordon@tceq.state.tx.us Kevin Mayes, TPWD, 512-754-6844, ext. 25Kevin Mayes, TPWD, 512-754-6844, ext. 25

Kevin.mayes@tpwd.state.tx.usKevin.mayes@tpwd.state.tx.us Mark Wentzel, TWDB, 512-936-0823Mark Wentzel, TWDB, 512-936-0823

Mark.wentzel@twdb.state.tx.usMark.wentzel@twdb.state.tx.us

http://www.twdb.state.tx.us/instreamflowshttp://www.twdb.state.tx.us/instreamflows/index.html/index.html