Study: No major impacts from Old Dillon Reservoir expansion
Dillon, CO Colorado
SUMMIT COUNTY – A plan to enlarge Old Dillon Reservoir would affect recreational use in the area temporarily and result in some impacts to wetlands, according to a draft Forest Service study released this week.
Completion of the environmental analysis is a huge step forward for the $6.4 million project. The agency will take public comment on the environmental analysis for 30 days. Local officials hope to begin construction next summer.
Dillon, Silverthorne and Summit County will share the cost of the project, which, first and foremost, would help bolster Dillon’s water supplies. The town relies mainly on surface water from Straight Creek, a source that’s susceptible to pollution. The town also felt a pinch during the 2002 drought, when Straight Creek flows dropped to record low levels.
The proposed project includes seven elements:
– enlarging the existing reservoir from 62 acre-feet to 288 acre-feet (an acre-foot is 326,000 gallons, so the capacity would go from a little over 2 million gallons to about 10.5 million gallons);
– restoring the outlet from ODR to the south to the Blue River (now Dillon Reservoir);
– reconstructing the head gate on Salt Lick Gulch and piping the entire length of the Dillon Ditch to serve the enlarged reservoir and improving the siphon under I-70;
– rehabilitating the outlet to Salt Lick Gulch;
– temporary road access improvements;
– burying existing overhead utility lines around Old Dillon Reservor; and
– wetland creation.
About 20 acres of wetlands would be affected by the reservoir enlargement, but the impacts would be addressed by adding new wetland on the southwest shorelines of the reservoir.
In the long run, there would no net impact to recreational uses in the area, according to Paul Semmer, land specialist with the Dillon Ranger District.
The enlargement of the reservoir would actually decrease total diversions from the Salt Lick Gulch drainage from 573 acre feet to 450 acre feet.
The reservoir and dams would permanently impact 10.1 acres of forest and meadow habitat in the project area, according to the draft study.