City of Abilene uses water from Brazos River to boost lake supply

by: Shelly Womack

ABILENE, Texas (KTAB/KRBC) - The City of Abilene has scalped 1 billion gallons of water from the Clear Fork of the Brazos River thanks to recent rainfall. This will boost the water supply at Lake Fort Phantom Hill.

For a perspective of just how much water this is, the Director of Water Utilities, Rodney Taylor, shared that a typical Olympic-sized swimming pool holds about one million gallons of water.

"So when you’re thinking of a billion [gallons], you’re thinking of 1,000 swimming pools," Taylor said. "So, in a scenario where you pump over a billion gallons, you’re capturing well over a month’s supply of water."

Abilene's average daily water consumption is approximately 22 million gallons each day. This extra supply will help the city meet the municipal and industrial needs. As of July 18, the lake is nearly 79% full.

The scalping process involves using large pumps to divert water from a river to a connecting lake at a higher elevation. It is not an everyday occurrence, as this process relies on things such as river flow, rainfall, reservoir capacity, costs and more.

A permit with the Texas Commission on Environmental Quality allows the city to divert water using a gated structure built across the river channel.

"When stream conditions are right, we can close gates and ‘impound’ water – we can stack it up behind the gates," Taylor said.

In ideal conditions, the city can transfer up to 30,000 acre-feet of water annually. An acre-foot is approximately 326,000 gallons of water.

"And then, we could take out about 25,000 acre-feet, our water right permit for yield out of the lake, for municipal and industrial purposes," Taylor said.

Before the gates can close and water can be collected, 600 acre-feet of water must pass through the measuring station within a 24-hour time frame. The original pump station, located on West Lake Road, consisted of three 50 million gallons per day capacity pumps. The five newer pumps add an additional capacity of 100 million gallons of water each day.

"Depending on the river flow, we can operate a combination of pumps to extract the available water," Taylor said. "Our pump capacity is designed to be just within the limits of the quantity that we can pump at any given time."

Taylor added that visitors should not expect to see the lake fill because of scalping, as water would need to be released, even if all pumps are engaged, "because the river has more capacity than the city has authorized capacity to pump."

Another factor that is taken into consideration is evaporation. Each year, the city loses approximately 58-60 inches of water due to the climate and wind exposure.

"On a hot day, even when we’re pumping a lot of water out of the lake, we’re losing more water to evaporation than we are from our maximum pumping rate,” he said. “Molecules are just flying off the surface of that water... But it’s still water that we would not have otherwise had access to."