Crosho Lake is a popular, secluded fishing location in the Routt National Forest at the foot of the Flat Tops, but for the past 15 years, many of the fish ended up in deadly shallow waters.
The lake holds arctic grayling and Colorado River cutthroat trout, and it serves an irrigation ditch that winds its way to about five ranches below, said U.S. Forest Service Fisheries Biologist Kathy Foster.
The fish need flowing water to spawn, and many have attempted to swim down the irrigation channel. The problem is the ditch doesn't carry much water, and many fish get trapped and die.
"You'd be surprised at the little trickle fish can swim up," Foster said.
Wednesday, while the water level at Crosho Lake was at its year-low, the U.S. Forest Service teamed up with the Colorado Division of Wildlife to build a stone barrier between the lake and the ditch. The barrier is constructed of rocks in wire baskets that will allow water to flow through the ditch, but prevent fish from swimming into it.
Dirt and larger rocks were filled in around the rock baskets with a track-hoe, sealing the levee that surround the south side of the lake. Although Crosho Lake is a natural lake, the levee was built in the late 1800s to hold an additional amount of about 23 vertical feet of water and improve its irrigation capabilities, said DOW District Wildlife Manager Bruce Sigler.
To prevent fish from jumping over the barrier, the barrier was built about 3 to 4 feet above the lake's highest water level, and an apron was built, extending about 4 feet horizontally toward the lake. Anything less, and the grayling and cutthroat could jump over, Sigler said.
The barrier project will cost about $3,000, and Foster says it's well worth it.
In the spring, the Forest Service saved about 200 fish that swam into the ditch by collecting them and restocking them in Crosho Lake, Foster said.
The lake has lost about that many fish each year, but the losses are more significant because their offspring also are lost, and it's more like losing 300 to 500 fish, Sigler said.
The fish are worth about $10 each, but restocking costs about $25 per fish, Sigler said.
Besides the ecologic and economic problems, people were simply netting fish out of the irrigation creek and taking them, instead of trying to return them to the lake, Sigler said.
"Now if they want the fish, they will have to use skill," said Diann Ritschard, public affairs specialist for the U.S. Forest Service.
Now that the fish cannot swim in the flowing waters of the irrigation ditch, it will be more difficult for them to spawn, but Crosho Lake does have at least one spring that could be suitable for spawning, Foster said. The barrier will greatly reduce the need to restock the lake and provide greater opportunities for public fishing.
Directions to Crosho Lake can be obtained by calling the Yampa Ranger District at 638-4516 or stopping by its office at 300 Roselawn in Yampa.
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