Monday, March 24, 2014

Drought Conditions Possible by Late April

Barton Springs discharge: 52 cfs 10-day avg.
Lovelady monitor well: 483.3 ft-msl

Water levels in the aquifer and flow at Barton Springs continue to gradually decline, after having reached their respective peaks in January and November, following the large storms in October of last year. According to the district rain gauge, March has received a total of 1.5 inches of rain so far, putting it on track to possibly reach its historic average of 2.2 inches. Despite the decent rainfall conditions we've seen this month, the preceding 3 months saw about 1/5 of their historic rainfall, leading to overall dry conditions and meager flow in streams where most of the recharge to the aquifer occurs. At the current rate of decline, without significant recharge to the aquifer, it is possible that Stage II Alarm Drought could be reached by late April based on water level in the District's Lovelady monitor well (see figure). Flow at Barton Springs will likely not reach its Stage II Alarm Drought threshold until later this Spring, perhaps mid-May. It only takes one, of the District's drought trigger sites to cross their respective threshold for a drought declaration to be made. The National Weather Service's Drought Outlook makes a range of predictions for parts of central Texas ranging from intensification of drought to slight improvement, depending on the county. The National Oceanic and Atmospheric Administration reports that the current ENSO cycle is currently in El Niño-Neutral, with some possibility of El Niño conditions arising in the summer or fall 2014. El Niño generally means wetter conditions for Texas. 

Tuesday, March 4, 2014

January and February see below Average Rain

No Drought
Lovelady monitor well: 487 ft-msl 
Barton Springs: 56 cfs (10-day average)

The "thunder-sleet" the Austin-area received last night may have slowed morning commutes, but brought a good start to the month of March with regards to precipitation. The rain gauge at the District office has recorded 0.69 inches so far since the start of the month, while the total historic average for March is 2.2 inches. The previous two months saw precipitation well below their respective historic averages. In January the total rainfall at the District office was 0.43 inches compared its historic average of 2.0 inches, while in February 0.44 inches fell compared to 2.4 inches historic average. Area creeks, where most of the recharge to the Barton Springs Segment of the Edwards Aquifer occurs, have scarcely flowed in 2014 due to predominantly dry conditions. As a result, water levels in the aquifer and flow rate of Barton Springs have been steadily declining. The recent rains were likely not large enough in magnitude to reverse the trend of heading towards drought. It is still too early to give an accurate prediction of when the District may surpass its drought thresholds if dry conditions persist, however it could occur sometime in the Spring. Below see a hydrograph of Lovelady monitor well, one of the District's drought triggers, since the end of 2012 through the present (click to enlarge). The graph shows the District's drought thresholds. Notice the end of the last drought cycle in the fall of 2013 and the peak of aquifer water levels in January of this year. The US Seasonal Drought Outlook predicts meteorological drought in much of the state to persist or intensify.