Scattered showers and thunderstorms brought some welcome relief to portions of the upper basin Tuesday and Wednesday. Areas around Menard and Mason received some of the higher total amounts of two to four inches over the last several days. Weather conditions are expected to be generally dry and warmer on Thursday and through the July 4th weekend. See Bob Rose's weather blog at http://www.lcra.org/water/conditions/weather/weather_column.html for the latest information on weather. Stream flow to the Highland Lakes has increased only minimally as a result of the recent rains.
The level of LakeBuchanan is 13.24 feet below its historic average for July. LakeTravis is 26.21 feet below the historic July average level. These lower lake levels reflect the ongoing rainfall deficit that started in the fall of 2007. The water temperature at the surface of Lake Travis is 84.8 degrees.
LCRA is releasing water from the HighlandLakes to meet municipal, industrial, power generation, agricultural irrigation and environmental needs. River flow between Bastrop and Columbus varies from about 1,700 to 2,600 cfs, while further downstream streamflow at Wharton is about 670 cfs due to agricultural diversions below Columbus. To see real-time hydrologic data please go to http://hydromet.lcra.org/.
Boater planning to launch from a public ramp at Lake Travis or Lake Buchanan will have only one boat ramp available at each lake until rains bring the lake levels back up.
Lake Travis update:
Currently, Mansfield Dam Recreation Area, located off Ranch Road 620 about five miles south of FM 2222, has the only public boat ramp available for boaters to use on Lake Travis over the Fourth of July weekend. It is usable until the lake level drops below 640 feet above mean sea level.
Since the beginning of the water recreation season, 11 of the 12 Lake Travis public boat ramps have become unusable as the lake level has fallen below the concret ramps. Many boaters still have access to the lake through private marinas and docks.
Travis County Parks, which operates the LCRA-owned parks around Lake Travis, wants boaters who are planning to visit Lake Travis over the holiday weekend to be aware of the conditions and plan accordingly. Additionally, two of the four lanes used to simultaneously launch multiple boats at Mansfield Dam are unusable, reducing the ramp's launch capacity by half.
Boaters planning to use the only open public boat ramp on the lake need to have patience for long lines and to anticipate that the park will be closed to vehicles when parking spaces are filled there and at the nearby Mansfield Dam Overlook Park, which is used for overflow trailer parking. Staff regularly closely the park on holiday weekends as early as noon when the parking areas are full. Drivers on RR 620 need to be aware of potential traffic issues as the park fills up and the line of vehicles backs up onto RR 620.
Without significant rainfall to replenish water released for downstream uses and lost to evaporation, Lake Travis will continue to drop more than two feet a week. The average elevation for Lake Travis in July is 669.28 feet above mean sea level. On July 3 in the morning, its elevation was 643.07 feet.
Lake Travis has been lower during past droughts.
October 2000: 640.24
October 1985: 636.58
November 1963: 615.02
Aug. 14, 1951 (the lake's all-time low elevation): 614.18
Boaters are reminded that while LCRA marks many of the known hazards on the HighlandLakes, it is impossible to mark all of them because the hazards change with the lake levels. Channel buoys typically mark the lake river channel and the deepest water. Also, with shallow areas increasing, life jackets are even more important because when boats run aground, their passengers may be thrown from the boat. For safe boating and swimming tips, go to www.nobodyswaterproof.com.
LakeBuchanan update:
Currently, White Bluff Park, located off FM 2341 about 12 miles north of State Highway 29, has the only public boat ramp available for boaters to use over the Fourth of July weekend.
Since the beginning of the water recreation season, three of the four LakeBuchanan boat ramps have become unusable as the lake level has fallen below the concrete ramps. Currently, WhiteBluffPark boat ramp, operated by BurnetCounty, is the only public boat ramp available for boaters to use over the holiday weekend. It is usable until the lake level drops below 998 feet above mean sea level. Many boaters still have access to the lake through private marinas and docks.
Without significant rainfall, LakeBuchanan is dropping more than half a foot a week as a result of irrigation releases, increased municipal water use and evaporation. The average elevation for LakeBuchanan in July is 1,013.86 feet above mean sea level. On July 1 at noon, its elevation was 1,000.61 feet.
Weather conditions are expected to be hot and generally dry through the Fourth of July weekend. A few scattered showers may develop next Sunday when a weak cold front moves into the area, but otherwise, the weather will be very summer-like. Because of the hot, sunny weather, folks planning on being outside should drink plenty of water, use sunscreen and try to limit their time in direct sunshine.
LakeBuchanan has been lower during past droughts:
January 2007: 997.95
October 2000: 994.73
September 1964: 986.63
September 9, 1952 (the lake's all-time low elevation 983.70
Boaters are reminded that while LCRA marks many of the known hazards on the HighlandLakes, it is impossible to mark all of them because the hazards change with the lake levels. Channel buoys typically mark the lake river channel and the deepest water. Also, with shallow areas increasing, life jackets are even more important because when boats run aground, their passengers may be thrown from the boat. For safe boating and swimming tips, go to www.nobodyswaterproof.com.
HighlandLakes recreation:
As a reminder, boating is not the only attraction along the HighlandLakes and lower Colorado River. Many lakeside businesses and parks offer opportunities for the holiday weekend. For more information, look online at lake-area chambers of commerce and the LCRA park Web site.
The Austin Parks and Recreation Department Park Police will ban the use of personal watercraft on LakeAustin on Saturday, July 4, from sunrise to sunset. The City of Austin has jurisdiction over LakeAustin. For more information, call Austin Park Police Lake Patrol at (512) 329-8841.
LCRA does not ban the use of any type of watercraft on lakes over which it has jurisdiction including Lakes Buchanan, Inks, LBJ, MarbleFalls, Travis, Fayette, and Bastrop.
Unscheduled releases could occur at any of the
HighlandLakes dams without notice to maintain lake levels, pass flood flows, meet sudden demands for hydroelectric power, or for testing and maintenance of equipment. In the event of high energy demands in Texas, the Electric Reliability Council of Texas (ERCOT) may call upon LCRA for hydroelectric generation at anytime without notice. Lakeside residents and lake users immediately downstream of the dams should take necessary precautions against possible high flows and higher lake levels.
Elevations contained in this summary are based on LCRA "legacy" or NGVD 29 datum and are not adjusted to the newer NAVD 88 datum. FEMA and the National Flood Insurance Program reference the NAVD 88 datum in their floodplain maps and regulations. Lake levels reported by LCRA should not be used to determine first floor elevation of buildings for compliance with floodplain regulations. Surveyors should refer to http://harn.lcra.org/ for information about LCRA GPS control marks and benchmarks.
LCRA's state-approved Water Management Plan for the operation of the HighlandLakes includes requirements to provide water for river habitat and water quality along the lower river ("Instream Flow Requirements") and for the health and productivity of Matagorda Bay ("Bay and Estuary Requirements"). These requirements vary from either lower "critical" or higher "target" amounts according to the amount of water stored in the Highland Lakes at different times of year, and from month to month according to seasonal environmental needs. 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 inflows and storms.
Instream Flow Requirements: The minimum or "critical" instream flow requirements are to maintain at least 46 cfs at the Austin river gauge at all times, and a mean daily flow of at least 120 cfs at the Bastrop river gauge on all days. When inflows to the HighlandLakes are sufficient, the requirements are to maintain at least target levels for mean daily flow at Austin, Bastrop, Columbus and Wharton, as shown in the table above.
Bay and Estuary Requirements: Based on the HighlandLakes storage on January 1, 2009, lower "critical" amounts for Bay and Estuary monthly inflow volumes apply in 2009. The minimum or "critical" Bay and Estuary requirement is at least 14,260 acre-feet to Matagorda Bay each month. The Bay and Estuary month-to-date inflow for June was 18,896 acre-feet, and the month-to-date inflow for July is 468 acre-feet, according to provisional data from the Colorado River near Bay City.
