Rocky Mountain National Park announced today the availability of the Grand Ditch Breach Restoration Final Environmental Impact Statement (EIS) Record of Decision. This project will restore the natural hydrological processes, ecological services, and wilderness character of the area in the Upper Kawuneeche Valley impacted by the 2003 Grand Ditch breach.
On May 30, 2003, the Grand Ditch, a trans-basin, water-diversion canal in the northwest corner of Rocky Mountain National Park breached its bank. The breach saturated an adjacent hillslope which gave way, sending a massive mud- and rock-slide down into Lulu Creek and the headwaters of the Colorado River. Approximately 22 acres and 1.5 miles of stream, riparian, upland, and wetland habitat were injured.
Implicit in this project is that the ecosystems restored are naturally dynamic and self-sustaining. The area impacted in the Upper Kawuneeche Valley contains more sediment, debris, and subsequent injuries from the breach than it would under natural conditions. This resulted in highly unnatural conditions within the project area as a large amount of excess sediment has been deposited into the system and remains in an unstable, erodible state. The estimated 47,600 cubic-yard debris flow from the breach changed the river channel, deposited a large debris fan, increased sedimentation along the Colorado River, altered aesthetics of a wilderness area, and killed and scarred trees. These impacts degraded the aquatic, riparian, and upland ecosystems, in addition to the wetland communities that support a unique array of species in comparison to other habitat types in the park.
The Grand Ditch Breach Restoration Final EIS Record of Decision selects the preferred alternative to guide restoration of the area within Rocky Mountain National Park that was impacted by the breach. This alternative will emphasize the removal of large debris deposits in the alluvial fan area and in the Lulu City wetland. Actions will be conducted to stabilize limited areas of unstable slopes and banks throughout the upper portions of the restoration area. Hydrology through the Lulu City wetland will be restored in the historical central channel through removal of large deposits of debris, relying on the historical channel to transport river flow. Small-scale motorized equipment will be used for stabilization and re-vegetation activities, while larger equipment will be used for excavation of large debris deposits and reconfiguration of the Colorado River through the Lulu City wetland.
The EIS evaluated potential environmental consequences of the proposed actions for each alternative. There will be short-term, adverse impacts on natural soundscape, wilderness, water resources, wetlands, visitor use and experience, and wildlife from restoration activities and the use of mechanized equipment. There will be long-term major benefits under the NPS preferred alternative as a result of a high level of restoration.
The Final EIS Record of Decision has been approved by the National Park Service Intermountain Regional Director. No implementation will begin until a notice of availability for the Record of Decision has been published in the Federal Register.
A copy of the Final EIS Record of Decision is available online. Printed copies may be obtained by calling the park's Information Office at (970) 586-1206.