Texas Environmental Flows Process Pursuant to SB3. Sam Vaugh, P.E. August 18, 2010

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1 Texas Environmental Flows Process Pursuant to SB3 Sam Vaugh, P.E. August 18, 2010

2 Topics of Discussion 1) Structure and products of Texas Environmental Flows Process established in 2007 by SB3 of the 80 th Texas Legislature. 2) Current activities of the Guadalupe, San Antonio, Mission, & Aransas Rivers and Mission, Copano, Aransas, and San Antonio Bays Bay & Basin Expert Science Team (GSA BBEST). 2

3 SB3 Environmental Flows Process EFAG BBASC Recommendations on Environmental Flow Standards & Strategies Other Needs Recommended Environmental Flow Regimes SAC BBEST Science Balance Environmental Flow Standards 3

4 Environmental Flows Advisory Group (EFAG) 1) Comprised of nine (9) members: a) Three (3) State senators b) Three (3) State representatives c) Three (3) from TCEQ, TWDB, and TPWD 2) Appoint Science Advisory Group (SAC) 3) Appoint Basin & Bay Area Stakeholder Committees (BBASC) 4

5 Texas Science Advisory Committee (SAC) 1) Comprised of diverse technical experts in areas relevant to evaluation of environmental flows. 2) Technical Guidance: a) Geographic Scope b) Use of Hydrologic Data c) Fluvial Sediment Transport (Geomorphology) d) Freshwater Inflow Regime for Estuaries e) Biological Overlays f) Nutrient & Water Quality Overlay g) Flow Regimes to Environmental Flow Standards h) Lessons Learned 5

6 Basin & Bay Area Stakeholder Committee (BBASC) 1) Must reflect a fair and equitable balance of interest groups concerned with the particular river basin and bay system for which the committee is established. 2) Interest groups include: agriculture, recreation, municipalities, soil & water conservation districts, refining industry, chemical manufacturing, electricity generation, commercial fishing, public interest, regional water planning, groundwater conservation districts, river authorities, and environmental. 3) Appoint Basin & Bay Expert Science Team (BBEST). 4) Provide recommendations on environmental flow standards & strategies by September 1,

7 Basin & Bay Expert Science Team (BBEST) 1) Comprised of technical experts with knowledge of the river basin and bay system and/or development of environmental flow regimes. 2) Charged to develop environmental flow analyses and recommended environmental flow regimes based on best available science through a consensus process. 3) Provide environmental flow regime recommendations by March 1, ) Provide technical support to the BBASC in work plan development. 7

8 SB3 Environmental Flows Process EFAG BBASC Recommendations on Environmental Flow Standards & Strategies Other Needs Recommended Environmental Flow Regimes SAC BBEST Science Balance Environmental Flow Standards 8

9 GSA BBEST Current Activities 1) Hydrology Subcommittee: a) Locations (gages) for flow regime development. b) Application of Hydrology-based Environmental Flow Regime (HEFR) method. 2) Instream Subcommittee: a) Habitat guilds and focal species identification. b) Refining methods to relate flow and habitat availability for focal species. 3) Estuary Subcommittee: a) Pilot salinity suitability analyses for oysters. b) Planning analyses for Rangia clams, white shrimp, and blue crabs. 9

10 Blanco Wimberley, TX Guadalupe Comfort, TX Guadalupe River near Spring Branch, TX San Marcos Luling, TX Plum Creek near Luling, TX Medina Bandera, TX Medina San Antonio, TX San Antonio River near Elmendorf, TX Guadalupe Gonzales, TX Sandies Creek near Westhoff, TX Guadalupe Cuero, TX Guadalupe Victoria, TX San Antonio River near Falls City, TX San Antonio Goliad, TX Cibolo Creek near Falls City, TX Mission Refugio, TX 10

11 Guadalupe Spring Branch

12 HEFR Matrix & Flow Regime Components Overbank High Pulse Base Subsistence 12

13 Habitat Availability Curves Source: Instream flows research, Lower Colorado River (BIO-WEST 2008). 13

14 Oysters, Rangia Clams, & White Shrimp White Shrimp Trawl CPUE x Salinity, Jly-Dec, catch_per_hour start_salinity_num 14

15 Questions, Comments, & Discussion 15

16 Use of the Hydrology-based Environmental Flow Regime (HEFR) Method HEFR is used to provide an initial characterization of environmental systems with readily available data in the absence of definitive data relating flow alteration to ecological response. Advantages: 1) Hydrology is a key variable for instream, and a good indicator for estuarine, environmental flows. 2) Consistent with TIFP and SAC guidance. 3) Lengthy records at multiple streamflow gage locations. 16

17 Use of the Hydrology-based Environmental Flow Regime (HEFR) Method HEFR is used to provide an initial characterization of environmental systems with readily available data in the absence of definitive data relating flow alteration to ecological response. Disadvantages: 1) Limited validation with biological, water quality, and geomorphological data. 2) Should/will be superseded by SB2 field studies. 3) Not useful where gage records are lacking or nonexistent. 17

18 Subsistence & Base Flows Wet Average Dry Seasons 18

19 High Flow Pulses & Overbank Flows Wet Dry & Average 19