2021 Critical Period Calculator

This auto-fill calculator allows you to accurately determine your authorized groundwater withdrawal amount for the current total number of days that a stage of Critical Period Management (CPM) has been in effect in the San Antonio and Uvalde Pools. To use, simply select the pool for your area along with the corresponding year of critical period and the program will automatically display the stage(s), number of days, and applicable reduction rates. To calculate your accurate reduction, enter your annual authorized groundwater withdrawal amount in the appropriate box and click the Calculate button. Your new authorized amount is displayed in red. Reset the calculator each time to repeat the process as necessary.

If you wish to forecast your possible end-of-year reduction please use the Critical Period Forecast Calculator or the Interactive Critical Period Calculator if you are an irrigation user who has filed a Notice of Intent to Finish Out a Crop form.



Calculated Data
Authorized Amount Before Reductions Pending acre-ft.
Current Critical Period Reduction Pending acre-ft.
New Authorized Amount After Reduction Pending acre-ft.

Please note that 2021 calculations are not final. These calculations are as of the current date and do not take into account any future reductions.

SA Pools
Stage % Days in Stage Start End Reduction
No Stage 0.0% 51 01/01/2021 02/20/2021 0%
Stage 1 20.0% 11 02/21/2021 03/03/2021 0.60%
No Stage 0.0% 20 03/04/2021 03/23/2021 0%
Stage 1 20.0% 26 03/24/2021 04/18/2021 1.42%
Stage 2 30.0% 11 04/19/2021 04/29/2021 0.90%
Stage 1 20.0% 7 04/30/2021 05/06/2021 0.38%
No Stage 0.0% 117 05/07/2021 08/31/2021 0%
Stage 1 20.0% 19 09/01/2021 09/19/2021 1.04%
262 4.34%
Uvalde Pool
Stage % Days in Stage Start End Reduction
No Stage 0.0% 262 01/01/2021 09/19/2021 0%
262 0%

DISCLAIMER
The above Critical Period calculator is made available to you by the Edwards Aquifer Authority ("EAA"). It is provided to you as a tool to monitor and manage your water use. The EAA makes no claims as to the accuracy or completeness of the results, for any particular purpose, produced by the calculator. If you use the results for any purpose, the responsibility of that use is entirely with you, the user. By using the calculator, you are accepting all the terms of the disclaimer notice.