Thursday, October 25, 2012

Aquifer Update

Drought Status: Non-Drought Conditions
Barton Springs: ~40 cfs (41.7 10-day average)
Lovelady: 481.4 ft-msl (172.0 ft depth to water)

Barton Springs discharge that is reported on the USGS website has been corrected to reflect manual verification measurements. The website was reporting values about 4 cfs too low.  District staff also measured springflow and verified the higher values. As such, we've avoided entry into drought for at least a couple of weeks--and hopefully we'll get some rainfall in the meantime.

Unfortunately, the El Nino conditions are very weak, if present at all, so future rainfall projections due to ENSO are not a source of optimism at this time.

Although the District is currently no under drought restrictions or declarations, here's what is happening around us:

Edwards Aquifer Authority:
o   Under Stage 2 restrictions (30% curtailment)  based on 10-day average values for J-17 (current reading:  648msl;  Stage II threshold 650msl, Stage III threshold 640msl). 
o   EAA Critical Stage Info (Triggers, Stages and Reductions)

City of Austin: 
o   Stage II restrictions are in effect (outdoor watering limited to 1 specified day per week, before 10am or after 7pm)
o   Stage II watering restrictions were implemented on Sept. 4, 2012.
o   Follows LCRA drought triggers (see next section).

Lower Colorado River Authority:
o   Water storage is at less than 900,000 acre feet and lakes are currently (10/22/2012) at 44% full (879,288 acre feet).  Check real time Lake Volumes.
o   When lakes reach 900,000 million acre feet, firm water customers required to reduce water use by 10-20%, and they start a curtailment of interruptible supply and environmental flows for critical needs continues.
o   2010 Water Management Plan Drought Triggers

Guadalupe-Blanco River Authority:
o   Currently in Stage 1 Mild Water Shortage Conditions.
o   Comal Springs at 211 cfs and Canyon Reservoir at 901.52 msl (10/22/2012).
o   Stage 1 Mild Water Shortage Conditions triggered when the water level drops below 895 feet in Canyon Reservoir (or less than 274,800 ac/ft of storage) and/or Comal Springs is at or below 250 cfs but greater than 200 cfs.  See 2011 Drought Contingency Plan for more info. 

Hays-Trinity Groundwater Conservation District:
o   The Board of Directors declared Alarm Stage Drought (20% reduction) on 9/1/2012.
o   Discharge readings for the Pedernales (27 cfs) have been below Alarm thresholds (31.6 cfs) for 3 days. (10/22/2012). 
o   Alarm Stage Drought triggers for are 30-day averages of 31.6 cfs for the Pedernales and/or 28.5 for the Blanco.

Thursday, October 11, 2012

Alarm Stage Drought Approaching

Drought Declaration Status: No Drought
Barton Springs discharge: 39 cfs (40.8 cfs 10-day average)
Lovelady Well:  168.8 ft depth to water (484.6 ft elevation)*

Without significant rainfall and recharge Barton Springs discharge could cross its Alarm Stage drought threshold in mid to late October. The Lovelady well will likely cross its threshold about 2-3 weeks later in early November. It only takes one indicator to cross its threshold for the Board to make a drought declaration.

Despite the better-than-average rainfall for parts of central Texas, the rainfall has not come in sufficient intensity or locations to keep us from entering back into drought conditions.  Streams and rivers are not flowing across the recharge zone and streams such as Onion Creek and the Blanco River are flowing below normal. Surface waters reservoirs such as Lake Travis reflect this fact and are currently at about 42% capacity.

The one glimmer of hope for relief from dry conditions the U.S. Seasonal Drought Outlook indicating this part of central Texas as improving into December. This is likely based upon El Nino conditions projected to strengthen in the next few months.

*The Board is on the verge of approving rules that would convert the drought thresholds for the Lovelady well from depth to water (in feet) to an elevation (feet above mean sea level). This is merely a conversion and does not influence the time or frequency of drought declarations from the established methodology.The image below is a summary of those conversions.