Creeks and rivers above the Highland Lakes are falling slowly after additional rainfall yesterday. This morning, the Colorado River near San Saba is falling slowly at 201 cfs, and the Llano River at Llano is also falling at 1,030 cfs. Sandy Creek near Kingland is flowing at 505 cfs and falling, as is the Pedernales River near Johnson City falling through 1,020 cfs this morning.
Lake Conditions
As of 7:30 am, the level of Lake Buchanan is at 997.54 ft msl which is about 16.3 feet below its historic May average of 1,013.88 ft msl. The level of Lake Travis is 642.34 ft msl which is about 29.3 feet below its historic May average of 671.77 ft msl. The total combined storage in the Highland Lakes two water storage reservoirs, Buchanan and Travis, is at 1,018,000 acre-feet, or 51 percent of capacity. The surface water temperature of Lake Travis as measured near Mansfield Dam is 76 degrees.
Lake levels reported by LCRA are not referenced to the NAVD 88 datum, and should not be used to determine first floor elevation of buildings for compliance with floodplain regulations. Surveyors should refer to: http://harn.lcra.org/website/harn/ for information about LCRA GPS control marks and benchmarks.
Dam Operations
There may be daily releases as needed from Buchanan and Inks dams to supply a share of the demand on the Highland Lakes. Releases from Wirtz and Starcke dams will be made today as needed to pass inflows through lakes LBJ and Marble Falls to Lake Travis. Releases may be made from Mansfield dam to supply water to the City of Austin and to maintain the level of Lake Austin within its normal operating range. No releases are scheduled from Tom Miller dam today. Please be advised that brief releases may occur at any of the Highland Lakes dams at any time for hydroelectric generation as needed.
Streamflow Conditions Below the Highland Lakes
Downstream from the Highland Lakes this morning, flow is elevated from recent rainfall. The Colorado River at Bastrop is flowing at 815 cubic feet per second (cfs) while the Colorado River at Columbus, higher from local runoff yesterday, is flowing at 5,185 cfs. Further downstream, Wharton is flowing at 2,130 cfs, while the Colorado River at Bay City is flowing at 3,090 cfs.
As of January 1, 2012 the combined storage of lakes Buchanan and Travis was below 1.1 million acre-feet as defined in the Water Management Plan and therefore environmental instream flow criteria and Bay and Estuary needs are now subject to the "critical" requirements.
Critical Instream Flow Requirements: The minimum instream flow requirement to meet critical needs is to maintain at least 46 cfs at the Austin river gauge at all times, and to maintain a mean daily flow of 120 cfs from Bastrop to Eagle Lake.
Critical Bay and Estuary Requirements: The minimum freshwater inflow to Matagorda Bay to meet critical needs is 14,260 acre-feet each month.
At times the lower river and Matagorda Bay may receive more water than required by the Water Management Plan because water is being delivered to downstream users or due to downstream storms and inflows.
Weather Outlook
For up to date weather forecasts (including a 7-day forecast) for your area go to: http://www.srh.noaa.gov/ewx/ and enter your Zip Code in the Local Forecast bar located in the upper left hand corner.
Colorado River Releases LCRA is operating the lakes under drought relief measures approved by the TCEQ in December and will not provide Highland Lakes water to most downstream farmers in 2012. LCRA still makes releases from the Highland Lakes for a variety of reasons. The water can be released to meet the needs of municipal and industrial customers, to generate electricity in emergencies and for the environmental requirements of the river and Matagorda Bay.
Colorado River Instream Flow Needs In a Critical Year, the Colorado River instream flow needs are defined by meeting specific minimum flows at four hydromet stations downstream of Longhorn Dam. For those locations, the Critical Flow for the current month and Yesterday’s Mean Daily Flow are displayed below:
Instream Flow Conditions
Location
Yesterday's Mean Daily Flow (cfs)
Critical Flow Criteria (cfs)
Colorado River at Austin
567
46
Colorado River at Bastrop
766
120
Colorado River at Columbus
2519
120
Colorado River at Wharton
3358
Matagorda Bay and Estuary Freshwater Inflow Needs In a critical year, Matagorda Bay inflow needs from the Colorado River are 14,260 acre feet per month.
