The Lightner Creek project began in 2009, out of concern for the amount of sediment that Lightner Creek was contributing to the Animas River, particularly during heavy precipitation events. The Lightner Creek Group was formed to address the issue, and includes San Juan Citizens Alliance, Trout Unlimited, City of Durango, and MSI.
The Lightner Creek Group formed the goal of reducing sediment inputs to the Animas, which should improve aquatic habitat and fishing conditions. Phase I of the project was completed by Basin Hydrology in March of 2010. MSI has taken the lead on the Phase II portion with a monitoring effort conducted from March through December 2010.
The main findings from the monitoring work include:
- Total suspended and bed load sediment volumes in Lightner Creek are greater than expected for a stream this size.
- The largest source of sediment to Lightner Creek is from Perrins Canyon.
- Sediment from Perrins Canyon is primarily delivered to Lightner Creek during late summer/early fall rain storms.
- The delivered sediment is mobilized to the confluence with the Animas contributing to water quality reduction downstream.
In 2012 the City of Durango constructed a sediment detention basin at the mouth of Perrins Canyon. We expect this to alleviate much of the short-term sedimentation issues in Lightner Creek. However, the longer-term supply of sediment from Perrins Canyon is still an issue, and of concern because of the maintenance cost associated with cleaning out the sedimentation basin, the gap in our understanding of the hill slope delivery in the canyon, and the possibility of other alternatives to reducing sedimentation to Lightner Creek.
In 2012 MSI will be working with the Animas River Watershed Partnership, and others to evaluate the sediment flux from Perrins Canyon.