The Texas Instream Flow Program Barney Austin Surface Water Resources Division Texas Water Development Board February 8 th, 2006

Instream flows methods Desktops methods : Consensus Environmental Planning Criteria Lyons Method Comprehensive methods : State methodology

Desktop methods

CPC for on-channel reservoirs

CPC for direct diversions

Comparison of flows…

Comprehensive methods

In 2001…Senate Bill 2 The Texas Legislature directed tri-agencies (TPWD, TWDB, and TCEQ) to: Establish and continuously maintain an instream flow data collection and evaluation program, and Develop methodologies to determine flow conditions in Texas rivers and streams necessary to support a sound ecological environment.

Senate Bill 2 Framework for Instream Flow Study Program requires tri-agencies to: Share oversight of program studies. Share data, studies, analysis, information and reports. Establish a Work Plan that prioritizes studies and sets interim deadlines for publication of flow determinations, and Complete priority studies by December 31, 2010.

Senate Bill 2 Framework for Instream Flow Study also: Requires TCEQ to consider the results of completed studies in its review of any management plans, water rights, or interbasin transfers.

Joint study accomplishments: Interagency MOA (Executed: Oct 17, 2002) Programmatic Work Plan (Final: Dec 19, 2002) Technical Overview (Draft: August 8, 2003) NAS review…

Summary of Agency Roles Instream Flow Study Element Coordinating Agency Study DesignJoint Hydrological and Hydraulic EvaluationTWDB Biological EvaluationTPWD Physical Processes EvaluationJoint Water Quality EvaluationTCEQ IntegrationJoint InterpretationJoint Study ReportJoint Monitoring and ValidationJoint

Texas Instream Flow Studies

Timeframes for Priority Studies Subbasin Lower Guadalupe River Lower Brazos River Lower San Antonio River Middle Trinity River Lower Sabine River Middle Brazos River Sabine R. Toledo Bend

Second Tier of Studies Upper Guadalupe River Neches River Red River Upper Sabine River Two special studies include the Sulphur River (on-going) and the Lower Colorado River (monitoring). Developed to provide future direction in studies in the event priorities change or supplementary resources are made available. These include: Sulphur R. Colorado R.

Hydrology & Hydraulics TCEQ - Water Availability Model (WAM)

Hydraulic Modeling – Brazos River DOQQ photo taken February 4, 1995; ~7,500 cfs Boundary of FE Mesh used for flows below 3350 cfs is shown in green. Detail Area

Hydraulic Modeling – Brazos River Finite Element Mesh (approximate element resolution 8m x 10m) RMA-2 (depth averaged, hydrostatic Reynolds Averaged Navier-Stokes equations) 1456 cfs shown FE mesh with depth contours 0.0m to 4.0m FE mesh with velocity contours 0.0 to 2.25 mps

Hydraulic Modeling – Brazos River Photo of “Island” area, November 2, Flow is approximately 1500 cfs.

Fish habitat utilization studies

Habitat Modeling– Brazos River Mesohabitats are delineated for 1456cfs using a grid-based GIS model

Modeling Issues – Large woody debris Large Woody Debris (LWD) influences both hydraulics and habitat utilization analysis North Sulphur (near confluence) South Sulphur near Cooper Sulphur US of Patman (near Site 2)

Modeling Issues – Mesh Interpolation MEBAA bounding boxes Typical radial bounding regions Interpolating bathymetric single-beam data to the finite element mesh Exploit the anisotropic shape of the river cross- section for a better interpolation Use flow-directional coordinate system (either linear {TWDB} or curvilinear {CRWR})

Modeling Issues – Mesh Interpolation Standard IDW interpolation using Surface Water Modeling System Improved IDW interpolation using Mesh Elevating and Bathymetry Adjusting Algorithms (MEBAA)

Modeling Issues - Geomorphology Bathymetry that changes with flow Surveying (High Flow) Modeling (Low Flow) Affects both hydraulic and habitat analysis

Physical Processes Flushing flows (> once per year) Restore/enhance riffle habitat Remove surficial and interstitial fine sediment Determined through study of sediment and hydraulic model output Channel maintenance (circa 1.5 per year) Maintain physical characteristics of the channel Study of flow-duration curves Floodplain maintenance (once per 1-10 years) Build and bring nutrients to the floodplain Extent and frequency from (existing?) 1-D models or aerial photos Valley maintenance Q25-ish

Dissolved Oxygen Toxic Criteria Aquatic Life Human Health Bacteria ---- Contact Recreation Chloride, Sulfate, Total Dissolved Solids pH as absolute minima and maxima Temperature as absolute maxima TCEQ – Water Quality & Specific Numeric Criteria

Floodplain - Oxbow Lakes Study of river- floodplain interaction and connectivity

National Academy of Sciences 1. Evaluate science and methodology in key documents 2. Review and provide advice on scientific and technical matters relevant to the Instream Flow Program 3. Evaluate findings and recommendations of Tasks 1 and 2 for consistency with the requirements of Texas law for the study of Instream Flows

NAS Committee 11 members, 4 from Texas: Dr. David Maidment (UT, Austin) Dr. Kirk Winemiller (TAMU) Dr. Clark Hubbs (UT, Austin) Dr. Kenneth Dixon (UNT, Denton)

NAS Public meetings Austin – Oct 2003 San Antonio – Jan 2004 San Marcos – Mar 2004 Report released in March 2005…

Summary (the good stuff) Developing instream flow recommendations for rivers is one of the most difficult and important challenges in applied ecological and physical sciences today.

Summary (the good stuff) The state of Texas shows an impressive commitment to designing and implementing an instream flow program…

Summary (the good stuff) The Texas agencies are commended for proposing a prospective, comprehensive instream flow program…the program will provide enormous benefits to the state over the next several decades and beyond.

Major Recommendations:

Two levels of oversight: State level for management and program consistency Local goals and approaches

Clear definition for “Sound Ecological Environment”

Goals…statewide and for individual subbasins

Ecological indicators: Responsive to flow For monitoring & validation Adaptive management Achieving “Sound Ecological Environment”

Existing information… How will it guide detailed technical evaluations?

Set Goals Study Design Detailed Technical Evaluations Monitoring, Evaluation, and Adaptive Management Study Report Integrate Technical Studies and Develop Instream Flow Recommendations Implementation

Spatial and temporal scale

Sequential steps… How to go from technical evaluations to flow recommendation

The Instream Flow program should be integrated with other water-related programs Water Quality Planning Permitting B&E

Independent, interdisciplinary peer review

Specific recommendations… Specific to each document Specific to elements Biology, H&H, Physical Processes…

Next steps… Update the TOD and PWP with stakeholder input Proceed with data collection in three priority basins Geomorphology conference upcoming…February 22 nd. Stakeholder meetings in May???

Instream Flow Study Program Results Will Be: An essential database for conservation of fish and wildlife resources in Texas. Used in the State’s water rights permitting process, and Incorporated into future regional and state water plans.

For more information… Barney Austin Texas Water Development Board Tel: