River Operations Report - Water Supply Operations

Summary

This River Operations Report provides information about LCRA's water supply operations.  Please see the Flood Summary Report for information about flood operations.

You can navigate to specific sections of the River Operations Report using the links below:

Data presented on this web page includes provisional data obtained by LCRA for the use of its professional staff. This data is retrieved and displayed automatically, and is subject to revision.

Current Operations and Conditions
Last Update: 12/20/2014 8:52 AM

Widespread rainfall from the storms Friday produced less than one inch across the Hill Country and as a result no significant runoff occurred in the rivers and tributaries flowing into the Highland Lakes.  Downstream of the Highland Lakes, rainfall rates ranged from 1 to 2 inches with some locations near Columbus and Bay City receiving almost 3 inches. 

The storms have moved out of the Colorado River watershed and no additional rainfall is expected at this time.  While no rivers or tributaries are expected to reach bankfull or flood stage, the flow in the lower river below Columbus will be slightly elevated over the next few days as the runoff from the event makes it way to Matagorda Bay.

Due to the ongoing severe drought, LCRA has no plans to lower any of the pass-through lakes this winter.  The pass-through lakes are lakes Inks, LBJ, Marble Falls and Austin.

Releases from Lake Austin are made as needed to meet customer needs, replace water that evaporated from Lady Bird Lake and along the lower river, and to supplement the natural flow of the lower river for environmental flow requirements.  Releases are made consistent with all applicable water rights and agreements.

Customers taking water from the Colorado River downstream of Lake Austin include Fayette Power Project, industrial customers in Matagorda County, the City of Pflugerville, Decker Creek Power Station, Lost Pines Power Park and others.  Environmental flow requirements include TCEQ requirements to maintain instream flows along the lower Colorado River and supply freshwater inflows to Matagorda Bay and estuary.

Releases from Lake Travis will be made as needed to supply water to customers along Lake Austin, and to replace water that is released or has evaporated from Lake Austin.  Customers taking water from Lake Austin include the City of Austin, West Travis County Public Utility Agency and others.

Releases from Lake Buchanan will be made as needed through Buchanan, Inks, Wirtz and Starcke dams to replace a portion of the water taken by cities, power plants, evaporation and other uses along lakes Inks, LBJ, and Marble Falls, and to replace a portion of the water that is taken or released from Lake Travis.  Customers taking water from the Highland Lakes above Mansfield Dam include the City of Cedar Park, Travis County WCID No. 17, the City of Leander, Lakeway MUD, Ferguson Power Plant and others.

In addition to passing through releases from upstream dams, water may be released from lakes Inks, LBJ, Marble Falls and Austin to pass through runoff from localized storms and control the level of these lakes.



Current Lake Levels
Lake (Dam)Date/Time of Last ReportLake Level
(ft msl)
7 Days Ago
(ft msl)
30 Days Ago
(ft msl)
Buchanan (Buchanan)12/21/2014 2:15 AM 986.52 986.49986.15
Inks (Inks)12/21/2014 2:15 AM 887.08 887.17887.09
LBJ (Wirtz)12/21/2014 2:15 AM 824.62 824.72824.71
Marble Falls (Starcke)12/21/2014 2:15 AM 736.24 736.31736.29
Travis (Mansfield)12/21/2014 2:15 AM 623.59 623.58621.95
Austin (Miller)12/21/2014 2:15 AM 492.00 492.05491.98


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12/20/2014 8:30 AM
Short term lake level forecasts for Buchanan and Travis:

Tomorrow: Buchanan = 986.5 ft msl, Travis = 623.6 ft msl
One week: Buchanan = 986.4 ft msl, Travis = 623.4 ft msl



Current Storage In Lakes Buchanan and Travis
LakeDate/Time
of Last Report
Lake Level


(ft msl)
Historical
December
Average
(ft msl)
Difference
From
Average
(ft)
Storage
When Full

(Ac-Ft)
Current
Storage

(Ac-Ft)
Current
Percent
Full
%
Difference
From Full

(Ac-Ft)
Buchanan 12/21/2014 2:15 AM986.521,010.6424.1 875,588 308,193 35 % 567,395
Travis 12/21/2014 2:15 AM623.59666.9043.3 1,134,956 383,350 34 % 751,606
Total Combined Storage in Lakes Buchanan and Travis 2,010,544691,54334%1,319,001




Upstream Flow Conditions and Gauged Inflows
LocationDate/Time
of Last Report
Current Flow


(cfs)
Previous Day
Average Flow

(cfs)
Inflow Runoff
Factor
Previous Day
Adjusted
Average Flow
(cfs)
Previous Day
Gauged Inflow
Volume
(Ac-Ft)
Colorado River near San Saba 12/21/2014 2:25 AM 51.1 511.035 53 104
Llano River at Llano 12/21/2014 2:25 AM 65.5 661.000 66 131
Sandy Creek near Kingsland 12/21/2014 2:25 AM 0.1 02.367 0 1
Pedernales River near Johnson City 12/21/2014 2:25 AM 23.2 222.030 44 87
Previous Day Total Gauged Inflows*    163323

Inflows to the Highland Lakes are measured at four streamflow gauges shown in the table above. A runoff factor is applied to the measured flow to account for additional inflows that may occur downstream of each gauge. When the natural flow of the Colorado River upstream of the Highland Lakes is abundant, LCRA stores the excess water in the Highland Lakes, and lake levels rise.


Downstream Flow Conditions
LocationDate/Time
of Last Report
Current Flow

(cfs)
Previous Day
Average Flow
(cfs)
Previous Day
Flow Volume
(Ac-Ft)
Colorado River at Austin 12/21/2014 2:25 AM 145 168332
Colorado River at Bastrop 12/21/2014 2:25 AM 680 6391,267
Colorado River at Smithville 12/21/2014 2:25 AM 731 5071,006
Colorado River above La Grange 12/21/2014 2:25 AM 457 1,0792,141
Colorado River at Columbus 12/21/2014 2:25 AM 2,200 2,0374,041
Colorado River near Altair 12/21/2014 2:25 AM 1,724 2,4584,875
Colorado River at Wharton 12/21/2014 2:25 AM 2,472 8061,598
Colorado River near Lane City 12/21/2014 2:25 AM 1,666 6291,248
Colorado River at Bay City 12/21/2014 2:25 AM 1,048 1,0892,160

Note: The U.S. Geological Survey's (USGS) Bay City Gauge is strongly affected by tides from the Gulf of Mexico and provisional gauge readings may be inaccurate when flow in the river at Bay City is low, below about 2,000 cfs.  Provisional data is subject to revision by the USGS.




Previous Day Releases
Lake (dam)Approximate
Time of Release
Average
Discharge
(cfs)
Discharge
Volume
(Ac-Ft)
Buchanan (Buchanan)12/19: No releases00
Inks (Inks)12/19: No releases00
LBJ (Wirtz)12/19: No releases00
Marble Falls (Starcke)12/19: No releases00
Travis (Mansfield)12/19: 5-6 pm109216
Austin (Miller)12/19: No releases00

The Average Discharge and Discharge Volume data in the table above are average daily flows and volumes discharged through hydroelectric generation at each dam.  At times, generally during flood operations or when hydroelectric generating units are out of service, additional water may be released through spillways or floodgates. 

The schedule for today’s hydroelectric generation is competitive electric market information, and is not available to the public. Water may be discharged suddenly and unexpectedly due to emergency hydroelectric generation or other reasons. Residents should exercise caution and avoid being in the water near the dams.

(Releases from Lady Bird Lake through Longhorn Dam are controlled by Austin Energy, the electric utility for the City of Austin.)



Instream Flow Conditions and Environmental Criteria
LocationCriteria
for Minimum
Flow
(cfs)
Previous Day
Minimum
Flow
(cfs)
Criteria
for Average
Flow
(cfs)
Previous Day
Average Flow

(cfs)
Colorado River at Austin 46149 168
Colorado River at Bastrop  588120639
Colorado River at Columbus  1,4491202,037

On Jan. 1, 2014, the combined storage of lakes Buchanan and Travis was 764,341 acre-feet. In accordance with the Water Management Plan, because storage was less than 1.4 million acre-feet, environmental flow requirements for instream flow are set to critical levels in 2014.

Critical instream flow levels are a minimum flow of at least 46 cubic feet per second (cfs) in the Colorado River at Austin, and an average flow of at least 120 cfs in the Colorado River from Bastrop to Eagle Lake, upstream of Wharton.




Freshwater Inflows to Matagorda Bay
MonthMonthly Inflow*
(Ac-Ft)
Monthly Criteria
(Ac-Ft)
January 36,865 14,260
February 23,816 14,260
March 45,960 14,260
April 18,694 14,260
May 186,259 14,260
June 59,721 14,260
July 19,303 14,260
August 8,353 14,260
September 32,164 14,260
October 16,909 14,260
November 48,342 14,260
December 14,260
Annual Total496,386171,120

The data in the table above shows monthly freshwater inflow volumes for 2014.  On Jan. 1, 2014, the combined storage of lakes Buchanan and Travis was 764,341 acre-feet. In accordance with the Water Management Plan, because storage was less than 1.1 million acre-feet, environmental flow requirements for Matagorda Bay's freshwater inflow needs are set to critical levels in 2014. At critical levels, the Water Management Plan requires LCRA to maintain monthly inflows of at least 14,260 acre-feet in the Colorado River at Bay City in all months. This requirement is subject to the availability of inflows to the Highland Lakes in excess of senior water rights.

Freshwater inflows to Matagorda Bay are measured at the U.S. Geological Survey's (USGS) Bay City gauge. However, this gauge is strongly affected by tides from the Gulf of Mexico and provisional gauge readings may be inaccurate when flow in the river at Bay City is low, below about 2,000 cfs. Provisional data is subject to revision by the USGS. At these low river flows, LCRA uses data from the Lane City gauge to determine the amount of freshwater flowing into the bay. The Lane City gauge is upstream of the Bay City gauge and is not influenced by tide. When determining freshwater inflows to the bay using the Lane City gauge, LCRA subtracts the water diverted from the river downstream of the Lane City gauge but upstream of the Bay City gauge. The monthly inflow volumes at the Bay City gauge, as determined by LCRA, are displayed above.




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