Rainy start to the new year brought no relief to Medina Lake, as the reservoir continues to shrink
A rainy start to 2024 brought no relief to Medina Lake, and the century-old Hill Country reservoir is continuing to shrink, slipping closer to historically low levels.
Here’s a look at the state of things at the lake, and at what it would take to bring its water levels back to normal:
How empty is Medina Lake?
Medina Lake is currently 3.1% full, according to data from the Texas Water Development Board. Water levels recorded this week have been just over 974 feet above sea level. That number that references the elevation of the top surface of the lake.
How low is that, really?
The Texas Water Development Board’s data goes back to 1997, and the lowest level recorded since then was 972.42 feet, on May 25, 2014. That’s less than two feet below the current level.
The lake is considered full when it reaches “conservation pool” at 1,064.2 feet. The last time the lake was that high was July 7, 2019.
How fast is the lake level dropping?
In the past month, the lake has fallen more than six inches, according to the board’s data. With the water level down more than 1 feet from three months ago, and more than 8 feet from this time last year, another hot and dry summer threatens to draw the lake down to a record low.
What will it take to refill the lake?
The lake was created by building a dam on the Medina River, which springs from the ground in northwest Bexar County. In order to replenish the lake, more water needs to be entering the lake than leaving it through the dam or by evaporation — and that hasn’t been the case.
Upstream of the reservoir, the river has seen some improvement. The river gauge at Bandera reported no flow at all from late July through early December, but since then, the flow rate has increased.
According to U.S. Geological Survey data, for the past two weeks, flows have ranged from about 5 to 10 cubic feet per second, a metric that measures the volume of water. That’s still far below normal. The median flow for this time of year is more than 50 cfs. USGS data shows a oneday surge above median flows on Feb. 10. However, that data is still considered provisional and hasn’t been reviewed and approved yet.
While the San Antonio area saw more rain in January, which helped improve drought conditions, more rain is needed to the north and west in Bandera and Medina counties to help refill the lake and get the river flowing.
The U.S. Drought Monitor shows a bullseye of “extreme drought” lingering over that area, stretching from Medina County through Kendall County and into Blanco County.
Why does Medina Lake matter?
The reservoir provides water to customers in three counties. The Bexar-medina-atascosa Water Control and Improvement District No. 1, known as BMA, manages the lake and distributes water to customers through a canal system. Its customers include a number of farmers who use the water for irrigation. According to the BMA, landowners use more than 46,000 acre feet of water from the lake. An acre-foot is the amount of water needed to cover one acre in one foot of water, or about 326,000 gallons.
The lake is also an important part of the tourism and recreation economy in Medina County.
The San Antonio Water System also has a contract to buy water from the lake, but hasn’t taken that water since 2015, which it says is due to low water levels and poor water quality. Under a contract from 2007, the city-owned utility is still paying the district millions of dollars for the water it isn’t using; last June, SAWS sued BMA in an effort to get out of the contract, which it inherited when it absorbed the former Bexar Metropolitan District in 2012.
That lawsuit is ongoing, according to Bexar County court records.