Edwards Aquifer Forecasts for 2014 Jim Winterle—EAA modeling supervisor HCP Stakeholder Committee May 28,
Risk Zones for Springs 2
2014 scenarios based on previous dry years Case 1: 10-year-average pumping rate of 385,000 acre-ft 3 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 years Case 1: 10-year-average pumping rate of 385,000 acre-ft 4 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 years Case 2: 40% reduction in permitted pumping = 350,000 acre-ft 5 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 years Case 3: 44% reduction in permitted pumping = 320,000 acre-ft 6 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 7
J-17 water-level changes for years that started below 650 feet 8
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 9
J-17 Forecast for
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 11