Thursday, July 16, 2009

2008-9 Drought Summary and Impacts

The BSEACD is not alone in its Critical Stage drought declaration. The Edwards Aquifer Authority in San Antonio and the Hays-Trinity Groundwater Conservation District have similarly issued Critical Stage declarations. Indeed, the drought is reaching historic proportions. Currently every county in Texas is reporting at least 1 impact from the drought. However, Hays and Travis counties report the most impacts of the state (source: drought impact reporter, link). Below is a quick summary of the drought in central Texas and some of its impacts.

Rainfall (or lack of it!)
  • 7 inch deficit to date for 2009;
  • 16 inch deficit from 2008 (~half of normal); 4th driest year since 1856, driest year since 1956.
That makes for one of the driest year and half periods we've had since we've keeping records in the late 1800's. 2008 was the driest year experienced since the 1950s. It is no surprise then that meteorologically this drought ranks as "Exceptional" according to the US Drought Monitor. The current drought is, according to State Climatologist, the most severe since the 1917-18 drought.

Surface Water
Lack of rain means no runoff, so streams and lakes are suffering.
  • Lake Travis is currently at 50% capacity; yearly inflows are likely to be the lowest ever recorded since it was built in the early 1940s.
  • USGS stream gauges that have readings are reaching their all-time low or are below their 10th percentile.

Water Levels
The lack of rain also translates into less recharge of the groundwater resources and therefore water levels and springs are reaching historic lows:
  • The Lovelady drought index well has reached depths equivalent to the 1950s drought--the worst in recorded history for our area;
  • Older, shallower wells in the Edwards Aquifer are going dry; many pumps within wells are being lowered;
  • The Trinity Aquifer has probably been hit the hardest to date, with many wells reported to have problems just west of the BSEACD in the Hays Trinity Groundwater Conservation District.
The lack of rainfall translates into less recharge, which results in declining water levels and ultimately declining springflow.
  • Barton Springs is at about 16-17 cfs (average is 69 cfs for this time of year), and has only been lower once in 30 years;
  • San Marcos Springs is flowing at 88 cfs (average is 191 for this time of year);
  • Jacob's Well (Trinity Aquifer spring in Wimbereley) has stopped flowing;
  • Anecdotal evidence from Hill Country residents indicate many smaller springs have stopped flowing.

Drought Outlook
The outlook over the next few months, save for any tropical system that moves into our area, is also grim. The image below is from drought outlook which shows our area for "drought to persist."

However, there is reason to be hopeful that the Fall will be wetter than normal. The national Oceanic and Atmospheric Administration indicates that we are moving into a "La Nina" system in the south Pacific, which generally indicates wetter conditions for much of Texas. Click here to find out more. Let's hope that happens!