Presenter:Presenter:Eric S. Hersh, University of Texas Eric S. Hersh, University of Texas at Austin Center for Research in at Austin Center for Research in

Water ResourcesWater Resources

TRRMS Annual SymposiumTRRMS Annual SymposiumMay 18, 2006May 18, 2006

New Tools to Assess New Tools to Assess Hydrologic Hydrologic Alteration Alteration

in Texasin Texas

AcknowledgementsAcknowledgements Co-authors:Co-authors:

David Maidment, UT-Austin CRWRDavid Maidment, UT-Austin CRWR Jordan Furnans, TWDBJordan Furnans, TWDB Mark Wentzel, TWDBMark Wentzel, TWDB Wendy Gordon, TCEQWendy Gordon, TCEQ

Thanks to:Thanks to: Joe Trungale, Trungale Engineering Joe Trungale, Trungale Engineering

and Science, formerly TPWDand Science, formerly TPWD

environmental flow environmental flow definitiondefinition

Water left in or released into a river Water left in or released into a river system, often for managing some aspect of system, often for managing some aspect of its conditionsits conditions Endangered species protectionEndangered species protection Healthy ecosystemHealthy ecosystem Sediment transportSediment transport Commercial fisheries yieldCommercial fisheries yield Freshwater inflows to bays and estuariesFreshwater inflows to bays and estuaries Waste assimilationWaste assimilation

flow- “the master flow- “the master variable”variable”

Controlling factor in Controlling factor in riverine physical, riverine physical, biological, and biological, and chemical processeschemical processes

e.g.: water e.g.: water temperature, temperature, dissolved oxygen, dissolved oxygen, available habitat, available habitat, spawning cues, spawning cues, channel shape, channel shape, substrate type, etcsubstrate type, etc

(Poff et al. 1997)

the natural flow regimethe natural flow regime

(Postel and Richter 2003)

Poff et al 1997

the natural flow regimethe natural flow regime

MagnitudeMagnitude FrequencyFrequency DurationDuration TimingTiming Rate of change of hydrologic eventsRate of change of hydrologic events

characterizing characterizing streamflowstreamflow

Subsistence flowSubsistence flow Water quality (temperature, DO, waste Water quality (temperature, DO, waste

assimilation)assimilation) Restricted habitat and connectivityRestricted habitat and connectivity

Base flowBase flow Dominant flow condition in many riversDominant flow condition in many rivers Determines available habitatDetermines available habitat Maintains groundwater tableMaintains groundwater table

Maidment et al 2005

Flow pulsesFlow pulses Within banksWithin banks Longitudinal connectivityLongitudinal connectivity Nutrient and organic matter deliveryNutrient and organic matter delivery Sediment flushingSediment flushing

Flood flowsFlood flows OverbankOverbank Lateral connectivityLateral connectivity Restructure channel and floodplainRestructure channel and floodplain ““Food bazaar”Food bazaar”

characterizing characterizing streamflowstreamflowMaidment et al 2005

quantifying quantifying environmental flowsenvironmental flows

207 assessment tools (Tharme 2003)207 assessment tools (Tharme 2003) 1950s-present1950s-present South Africa, Australia, United StatesSouth Africa, Australia, United States

Hydrologic (Desktop) ModelsHydrologic (Desktop) Models Hydraulic ModelsHydraulic Models

Habitat ModelsHabitat Models Holistic ModelsHolistic Models

Senate Bill 2Senate Bill 2

In 2001, the tri-agencies (TPWD, TWDB, In 2001, the tri-agencies (TPWD, TWDB, and TCEQ) were directed to:and TCEQ) were directed to: Establish and maintain an instream flow data Establish and maintain an instream flow data

collection and evaluation programcollection and evaluation program Develop methodologies to determine flow Develop methodologies to determine flow

conditions in Texas rivers and streams conditions in Texas rivers and streams necessary to support a sound ecological necessary to support a sound ecological environmentenvironment

(Austin 2005)

hydrologic alteration hydrologic alteration softwaresoftware

The Nature ConservancyThe Nature Conservancy

USGSUSGS

The Indicators of The Indicators of Hydrologic Alteration (IHA)Hydrologic Alteration (IHA) Richter et al., 1996 & 1997Richter et al., 1996 & 1997 33 Annual Statistics33 Annual Statistics Parametric (mean) or non-parametric Parametric (mean) or non-parametric

(median)(median) One or two period analysisOne or two period analysis Range of Variability Approach (RVA) to Range of Variability Approach (RVA) to

quantify hydrologic alterationquantify hydrologic alteration 34 Environmental Flow Components (EFCs) 34 Environmental Flow Components (EFCs)

from NAS review (Mallard et al. 2005)from NAS review (Mallard et al. 2005)

IHAIHA Input: 20+ Input: 20+

yrs of daily yrs of daily flow data flow data recommendedrecommended

Output: Output: scorecards scorecards spreadsheet, spreadsheet, summary and summary and alteration alteration graphsgraphs

National HAT: USGS Fort Collins National HAT: USGS Fort Collins Science Center and Colorado Science Center and Colorado State Univ.State Univ.

171 indices from 13 papers (in 171 indices from 13 papers (in Olden and Poff 2003), including Olden and Poff 2003), including the 33 IHAthe 33 IHA

Input: daily and peak (optional) Input: daily and peak (optional) flow dataflow data

Six stream classifications Six stream classifications from Poff 1996from Poff 1996 420 U.S. rivers420 U.S. rivers

Hydrologic Assessment Tool Hydrologic Assessment Tool (HAT)(HAT)

HATHAT New Jersey Hydrologic Index Tool (HIT) New Jersey Hydrologic Index Tool (HIT)

with NJ Department of Environmental with NJ Department of Environmental ProtectionProtection Includes NJ Stream Classification ToolIncludes NJ Stream Classification Tool Principal components analysis to identify 10 Principal components analysis to identify 10

significant indices for each of 4 state-specific significant indices for each of 4 state-specific stream typesstream types

Missouri and Massachusetts under Missouri and Massachusetts under developmentdevelopment

Texas possibly next yearTexas possibly next year

IHA/HAT ComparisonIHA/HAT Comparison Both are simple, user-friendly statistical tools to Both are simple, user-friendly statistical tools to

evaluate hydrologic characteristics evaluate hydrologic characteristics

Both are based on daily flow data time series which Both are based on daily flow data time series which typically encompasses flow alterationtypically encompasses flow alteration

Both have built-in temporal comparison tools; neither Both have built-in temporal comparison tools; neither has spatial comparison toolshas spatial comparison tools

HAT features more statistical routines and flexibility, HAT features more statistical routines and flexibility, but ‘significant’ indices chosen from a national dataset but ‘significant’ indices chosen from a national dataset likely not representative of Texas conditionslikely not representative of Texas conditions

Ecological significance of specific indices in both is Ecological significance of specific indices in both is unclear in Texasunclear in Texas

Texas Texas Instream FlowInstream FlowStudiesStudies

(Austin 2005)

TIFP priority basinsTIFP priority basins

n = n = 2424

!(

!(!(

!(

!(!(

!(

!(

!(

!(!(

!(

!(!(!(

!(

!(!(

!(

!(

!(!(

!(!(

BrazosBrazos

SabineSabine

TrinityTrinity

GuadalupeGuadalupeSan AntonioSan Antonio

Spatial Patterns: Texas Spatial Patterns: Texas StreamflowStreamflow

Daily Flow08020000 - Sabine Rv nr Gladewater, TX

1630

682

179127

332

10601610 1935 1570

87 96

718

1

10

100

1,000

10,000

100,000

J J M A M J J A S O N D

Month

Flo

w (

cfs

)

95th

75th

median

25th

5th

Daily Flow 08065000, Trinity nr Oakwood

1020

5920

3585

8201050

18602740 3380 3150

672 728

1510

1

10

100

1,000

10,000

100,000

J J M A M J J A S O N D

Month

Flo

w (

cfs

)

95th

75th

median

25th

5th

Daily Flow08168500 - Guadalupe Rv abv Comal Rv at New Braunfels, TX

246

348330

181 189

229 274 299 292

155 175

182

1

10

100

1,000

10,000

100,000

J J M A M J J A S O N D

Month

Flo

w (

cfs

)

95th

75th

median

25th

5th

Daily Flow08188500, San Antonio at Goliad

286

440388 344 374

392 408392

389

254335

367

1

10

100

1,000

10,000

100,000

J J M A M J J A S O N D

Month

Flo

w (

cfs

)

95th

75th

median

25th

5th

Spatial Patterns: Texas Spatial Patterns: Texas StreamflowStreamflow

For streamflow periods of record at the 24 For streamflow periods of record at the 24 priority gages (average of 68 years): priority gages (average of 68 years): Across the range of flow variability, Across the range of flow variability,

streamflow follows a sinusoidal pattern with a streamflow follows a sinusoidal pattern with a spring peak (May-June) and a fall trough spring peak (May-June) and a fall trough (August-September)(August-September)

Signal is stronger to the east, muted to the Signal is stronger to the east, muted to the west along the Texas coastwest along the Texas coast

Spatial Patterns: Texas Spatial Patterns: Texas HydrologyHydrology

Sabine Basin

0.01

0.10

1.00

10.00

1-Jan 31-Jan 2-Mar 2-Apr 2-May 2-Jun 2-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 31-Dec

Date

Me

dia

n M

on

thly

Un

it F

low

& M

on

thly

Pre

cip

ita

tio

n (

inc

he

s)

Sabine Rv nr Gladewater, TX

Sabine Rv nr Bon Wier, TX

Big Cow Ck nr Newton, TX

Sabine Rv nr Ruliff, TX

Sabine Rv nr Gladewater PRISM

Sabine Rv nr Bon Wier PRISM

Big Cow Ck nr Newton PRISM

Sabine Rv nr Ruliff PRISM

Q

P

Q

P

Trinity Basin

0.01

0.10

1.00

10.00

1-Jan 31-Jan 2-Mar 2-Apr 2-May 2-Jun 2-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 31-Dec

Date

Me

dia

n M

on

thly

Un

it F

low

& M

on

thly

Pre

cip

ita

tio

n (

inc

he

s)

Trinity Rv nr Rosser, TX

Trinity Rv at Trinidad, TX

Trinity Rv nr Oakwood, TX

Trinity Rv at Romayor, TX

Trinity Rv nr Rosser PRISM

Trinity Rv at Trinidad PRISM

Trinity Rv nr Oakwood PRISM

Trinity Rv at Romayor PRISM

Q

P

Middle Brazos Basin

0.01

0.10

1.00

10.00

1-Jan 31-Jan 2-Mar 2-Apr 2-May 2-Jun 2-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 31-Dec

Date

Me

dia

n M

on

thly

Un

it F

low

& M

on

thly

Pre

cip

ita

tio

n (

inc

he

s)

Brazos Rv nr Aquilla, TX

Brazos Rv nr Highbank, TX

Leon Rv at Gatesville, TX

Little Rv nr Cameron, TX

Brazos Rv nr Aquilla PRISM

Brazos Rv nr Highbank PRISM

Leon Rv at Gatesville PRISM

Little Rv nr Cameron PRISM

Q

P

Guadalupe Basin

0.01

0.10

1.00

10.00

1-Jan 31-Jan 2-Mar 2-Apr 2-May 2-Jun 2-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec 31-Dec

Date

Me

dia

n M

on

thly

Un

it F

low

& M

on

thly

Pre

cip

ita

tio

n (

inc

he

s)

Guadalupe Rv abv Comal Rv at New Braunfels, TX

Blanco Rv at Wimberley, TX

Guadalupe Rv at Cuero, TX

Guadalupe Rv at Victoria, TX

Guadalupe Rv abv Comal Rv at NB PRISM

Blanco Rv at Wimberley PRISM

Guadalupe Rv at Cuero PRISM

Guadalupe Rv at Victoria PRISM

Spatial Patterns: Texas Spatial Patterns: Texas StreamflowStreamflow

For the period 1961-1990:For the period 1961-1990: precipitation is bimodal, irrespective of precipitation is bimodal, irrespective of

geography, with spring (May-June) and fall geography, with spring (May-June) and fall (September-October) peaks(September-October) peaks

Signal is expressed in magnitude (more Signal is expressed in magnitude (more precipitation to the east) but not in timingprecipitation to the east) but not in timing

Spatial Patterns: Possible Spatial Patterns: Possible CausesCauses

Evapotranspiration Evapotranspiration More vegetation to the eastMore vegetation to the east More available water to the eastMore available water to the east

Groundwater rechargeGroundwater recharge Water demand and reservoir operations Water demand and reservoir operations

timingtiming

Future WorkFuture Work

Continue to investigate flow regime Continue to investigate flow regime characteristics and patterns which may impact characteristics and patterns which may impact instream flow analyses in the six priority instream flow analyses in the six priority basins basins

Compare the relative merits of IHA and HAT Compare the relative merits of IHA and HAT for the Texas Instream Flow Programfor the Texas Instream Flow Program

Recommend enhancements to one of the tools Recommend enhancements to one of the tools to increase effectiveness in Texas studiesto increase effectiveness in Texas studies

Work toward an integrated statewide stream Work toward an integrated statewide stream classification systemclassification system

Questions?Questions?

ReferencesReferences Austin, B. (2005) The Texas Instream Flow Program. Presentation at the Environmental Flows Austin, B. (2005) The Texas Instream Flow Program. Presentation at the Environmental Flows

Conference, Texas State University, San Marcos, October 31.Conference, Texas State University, San Marcos, October 31.

Maidment, D., Montagna, P., Sansom, A., Ward, G., Winemiller, K. (2005). Scientific Principles for Maidment, D., Montagna, P., Sansom, A., Ward, G., Winemiller, K. (2005). Scientific Principles for Definition of Environmental Flows. Statement for Environmental Flows Conference, Texas State Definition of Environmental Flows. Statement for Environmental Flows Conference, Texas State University, San Marcos, October 31.University, San Marcos, October 31.

National Research Council Committee (2005). National Research Council Committee (2005). The Science of Instream Flows: A Review of the The Science of Instream Flows: A Review of the Texas Instream Flow ProgramTexas Instream Flow Program. Committee on Review of Methods for Establishing Instream Flows . Committee on Review of Methods for Establishing Instream Flows for Texas Rivers, National Research Council. The National Academies Press, Washington, D.C. for Texas Rivers, National Research Council. The National Academies Press, Washington, D.C.

Olden, J.D., and Poff, N.L. (2003). Redundancy and the choice of hydrologic indices for Olden, J.D., and Poff, N.L. (2003). Redundancy and the choice of hydrologic indices for characterizing streamflow regimes. characterizing streamflow regimes. River Research and Applications,River Research and Applications, 19, 101-121. 19, 101-121.

Poff, N.L. (1996). A hydrogeography of unregulated streams in the United States and an Poff, N.L. (1996). A hydrogeography of unregulated streams in the United States and an examination of scale-dependence in some hydrological descriptors. examination of scale-dependence in some hydrological descriptors. Freshwater BiologyFreshwater Biology, 36, 71-91., 36, 71-91.

Poff, N. L., Allan, J. D., Bain, M. B., Karr, J. R., Prestegaard, K.L., Richter, B. D., Sparks, R. E., and Poff, N. L., Allan, J. D., Bain, M. B., Karr, J. R., Prestegaard, K.L., Richter, B. D., Sparks, R. E., and Stromberg, J. C. (1997). The natural flow regime. Stromberg, J. C. (1997). The natural flow regime. BioscienceBioscience, 47(11), 769-784., 47(11), 769-784.

Postel, S. and Richter, B. (2003). Postel, S. and Richter, B. (2003). Rivers for Life: Managing Water for People and NatureRivers for Life: Managing Water for People and Nature. Island . Island Press: Washington, D.C.Press: Washington, D.C.

Richter, B. D., Baumgartner, J. V., Powell, J., and Braun, D. P.(1996). A method for assessing Richter, B. D., Baumgartner, J. V., Powell, J., and Braun, D. P.(1996). A method for assessing hydrologic alteration within ecosystems. hydrologic alteration within ecosystems. Conservation BiologyConservation Biology, 10(4), 1163-1174., 10(4), 1163-1174.

Richter, B. D., Baumgartner, J. V., Wigington, R., and Braun, D. P. (1997). How much water does a Richter, B. D., Baumgartner, J. V., Wigington, R., and Braun, D. P. (1997). How much water does a river need? river need? Freshwater BiologyFreshwater Biology, 37(1), 231-249., 37(1), 231-249.

Tharme, R. E. (2003). A global perspective on environmental flow assessment: Emerging trends in Tharme, R. E. (2003). A global perspective on environmental flow assessment: Emerging trends in the development and application of environmental flow methodologies for rivers. the development and application of environmental flow methodologies for rivers. River Research River Research and Applicationsand Applications, 19(5-6), 397-441., 19(5-6), 397-441.