methods to promote freshwater inflow to east matagorda bay
TRANSCRIPT
1. June 21, 2013 Methods to promote freshwater inflow to East Matagorda Bay 2. 2 Problem Statement Elevated salinity and Reduced Circulation 3. 3 What are we addressing? - What amount of water could provide benefits? - Where to divert the water? - How to convey the water? - What are rough costs? Senate Bill 3 BBASC 4. 4 Conveyance Alternative? Live Oak Creek, Lake Austin tributary mile 5. 5 Conveyance Alternative? Lake Austin Natural conveyance or Pipeline/siphon 6. 6 Simplest option to infuse fresher water 3 miles 2 miles 7. 7 Another option during hypersaline periods < mile 8. 8 Possible transmission pathways Scenario 1 Scenario 2 D1 R2 R3 D2 Scenario 3 R1 R4 Scenario 4 Scenario 5 Scenario 6 D3 D5 D4 D6 Scenario 7 9. 9 Salinity Goals - Reduce extended periods of salinity greater than 30 ppt - Macrobenthos (Palmer et al.) - Oysters 2 year average (MBHE) 10. 10 Salinity Goals - Promote Fair salinity ranges during particular months (MBHE) - 20-23 ppt - Atlantic Croaker (Jan-Jun) - Gulf Menhaden (Apr-Aug) - 20-25 ppt - White Shrimp (Jul-Nov) - Blue Crab (Feb-Jun) - 30-32 ppt - Brown Shrimp (Apr-Jul) 11. 11 Salinity Habitat Interface Tool - Maps showing focus area (Hab output and Salinity output) - EMB 1/6 - Lake Austin? 12. 12 East Matagorda Bay 13. 13 Salinity 14. 14 Salinity % Rank 97pctl 88pctl 63pctl 44pctl 22pctl 05pctl 37% of days above 30 ppt 56% of days above 25 ppt 15. 15 Salinity % Rank 97pctl 88pctl 63pctl 44pctl 22pctl 05pctl 15 months 12m 17m 17m 17m 14 months 6m 11m 10m 12m 16. 16 Salinity % Rank 97pctl 88pctl 63pctl 44pctl 22pctl 05pctl +2.5 ppt per month 17. 17 MBHE Salinity Model - Animation 18. 18 East Matagorda Bay 19. 19 Salinity % Rank 97pctl 88pctl 63pctl 44pctl 22pctl 05pctl16,250 acft 273 cfs 30 days 5 months 30ppt Sep 1 30ppt Feb 6 33ppt Mar 17 Estimated benefit: 3-5 months 20. 20 Summary - 16,250 ac-ft of freshwater - Positive impact - 25% of EMB - Three to five months 21. 21 Next steps: refinement - Environmental benefits - Timing and amount - Cost (capital and O&M) - Salinity of source water - Freshwater flow available - Permitting - Summary - Recommendations 22. 22 More next steps 23. 23 We welcome your input! - Colorado/Lavaca BBASC - Texas Water Development Board - Meadows Center for Water and the Environment - US Army Corps of Engineers - Harte Research Institute - Other Stakeholders Barney Austin [email protected] Tel: (512) 826-2604