GWSSA’s request comes after a dry summer and light runoff from spring La Sal Mountain snow pack has left the lake with very little water and poor prospects for improvement this fall. Last month, GWSSA asked agricultural water users, who rely on Ken’s Lake for irrigation water, to reduce their use.
The current agreement between the district and the BLM requires that a minimum conservation pool containing 400 acre feet of water must be left in the lake at all times. But the agreement allows for a waiver in dire times, according to Lynn Jackson, Moab BLM area director.
The agreement also requires that a minimum flow of 3 cubic feet per second must be maintained below the Sheley Tunnel diversion that draws water from Mill Creek into the lake.
But the BLM recently agreed to allow GWSSA to draw down the lake to 100 acre feet if that is necessary. That minimum level of 100-acre-feet must be carefully monitored to be sure it is not violated, according to Jackson.
“We could go down to 120 acre feet,” said Mark Sovine, GWSSA manager. “I expect to go to 200 acre feet by October 1, but there will not be fish flopping around in the mud.”
A few fish might end up caught in isolated pools away from the main pool, Sovine said.
Jackson said state Division of Wildlife Resource officers agree that most of the fish will survive even if the lake level is reduced as low as 100 acre feet. He said the drain pipe that pulls water from the lake is located high enough from the bottom of the lake that the water level cannot be lowered below 100 acre feet.
“We don’t anticipate dead fish,” Jackson said. “If they appear, we’ll figure out how to deal with that.”
At 100 acre feet the remaining pool would be from 4- to 6-feet deep and large enough that winds will keep the water sufficiently oxygenated for fish to survive, Jackson said.
DWR is considering some sort of free fishing project involving local fishers and children to reduce the number of fish, Jackson said. He noted that Ken’s Lake is a recreational, not a natural, fishery. It is stocked twice a year, and there are no threatened or endangered fish in the lake, Jackson said.
Water flow data posted on the U.S. Geological Survey website shows that the district has faithfully maintained a flow of just over 3 cubic feet per second in Mill Creek below the Sheley Tunnel diversion all summer long.
The flow above the diversion has declined from about 6 cubic feet per second in July to just over 4 cubic feet per second in the last couple of weeks.
Sovine said that, with the lake draw down, the agency will be able to provide irrigation water to agricultural users, including wine makers in Spanish Valley, who need a small amount of water in the fall to keep their grape crops alive through the winter.