Thursday, May 30, 2013

Rain not enough to cause flow in Onion Creek; Recharge minimal

Stage III Critical Drought
Barton Springs: 28.3 cfs 10-day average
Lovelady monitor well: 461.3 ft-msl

The rains that came through the area last weekend (May 25-26) helped diminish the rainfall deficit that has grown over the course of the drought declared in November 2012. As of May 30, 2013  the total rainfall deficit since November 2012, compared to the historical average of 19.4 inches over that time period, is -6.2 inches according to district rain gauge totals.

As welcome as any rain during periods of drought, the recent rains were not large enough to generate substantial runoff, and consequently flow in the creeks responsible for the majority of the recharge that enters the Barton Springs segment of the Edwards Aquifer was also minimal. Despite not having generated substantial recharge to the aquifer, the rains have replenished soil moisture such that another storm in the coming days would be more likely to create the much needed recharge.

Barton Springs flow experienced a spike in discharge reaching a 35 cfs day-average on May 26, but is once again on the decline with a 10-day average of 28.3 cfs as of today and the USGS reporting 28 cfs as the most recent instantaneous discharge measurement. Lovelady monitor well showed a small leveling out of its water level due to the rain but is once again on the decline.

The U.S. Drought Outlook by the National Weather Service shows ongoing drought with "some improvement" and the U.S. Drought monitor rates the drought in Travis and Hays counties as moderate to severe.

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