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Edwards Aquifer Forecasts for 2014. Jim Winterle—EAA modeling supervisor HCP Stakeholder Committee May 28, 2014. Risk Zones for Springs. 2014 scenarios based on previous dry years Case 1: 10-year-average pumping rate of 385,000 acre-ft .
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Edwards Aquifer Forecasts for 2014 Jim Winterle—EAA modeling supervisor HCP Stakeholder Committee May 28, 2014
2014 scenarios based on previous dry yearsCase 1: 10-year-average pumping rate of 385,000 acre-ft • 23 Scenarios dip into the 60 cfs risk zone: ≈35% probability • 17 scenarios dip into the 30 cfs risk zone: ≈25% probability
2014 scenarios based on previous dry yearsCase 1: 10-year-average pumping rate of 385,000 acre-ft • 23 Scenarios dip into the 60 cfs risk zone: ≈35% probability • 17 scenarios dip into the 30 cfs risk zone: ≈25% probability
2014 scenarios based on previous dry yearsCase 2:40% reduction in permitted pumping = 350,000 acre-ft • 21 Scenarios dip into the 60 cfs risk zone: ≈31% probability • 17 scenarios dip into the 30 cfs risk zone: ≈25% probability
2014 scenarios based on previous dry yearsCase 3: 44% reduction in permitted pumping = 320,000 acre-ft • 19 Scenarios dip into the 60 cfs risk zone: ≈28% probability • 16 scenarios dip into the 30 cfs risk zone: ≈23% probability
Index Well J-17: analysis of changes from January 1 water levels Median peak summer decline is 15.8 feet Mean is 13.2 feet
J-17 water-level changes for years that started below 650 feet
J-17 maximum water level decline for years that started below 650 feet Greatest J-17 decline of -21 feet was in 1990 when annual pumping was high at 489,000 acre-feet
Conclusions • Analysis of prior drought scenarios suggests at approximately a 1-in-4 chance that springflow at Comal Springs will fall below 30 cfs by late summer, and a 1-in-3 chance that they will fall below 60 cfs • Without above normal rainfall, we can expect J-17 water levels to decline 10 to 20 feet by late summer, making Stage IV likely and Stage V possible • Critical period withdrawal limits and average or better rainfall will help to reduce the amount of decline • The chances that we will end the year above Stage II restrictions are about 1-in-4 • The chances that we will end the year above Stage I restrictions are about 1-in-8