Clayey sand with rock fragments (0- 10'), underlain with decomposed rhyolite (10' - 15') and rhyolite with interbedded clay and clayey sand lenses (15' - 50').
On May 30, 2003, the Grand Ditch, a water-diversion canal in the northwest corner of Rocky Mountain National Park breached its bank due to a suspected rockslide into the ditch. At the time of the event, estimated flow from the ditch was 260 cubic feet per minute.
The breach saturated an adjacent slope which gave way, sending a massive (48,000 cubic yards) 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 damaged.
Rocky Mountain National Park personnel and a team of cooperating researchers evaluated the extent of the damage and determined the desired future conditions for the impacted area.
Restoration needed to address many concerns in this rugged and remote area. These concerns included short-and-long-term potential impacts to wilderness character; geological resources; geological hazards; surface and groundwater hydrology; stream channel, floodplain and wetland morphology, and function; water quality; riparian and wetland communities; species of special concern (plants and animals); wildlife habitat and visitor experience.
An Environmental Impact Statement (EIS) was prepared. The results included recommendations for stabilizing the steep, unstable slopes with an engineered solution that would address both the geotechnical and ecological concerns.
To comply with the EIS recommendations and to address the objectives of the project, approximately 85,000 square feet of Anchored TECCO G65/3mm was specified for the project.
As this is an exposed slope and is visible across a large valley, a colored powder coating was applied to the TECCO® System to match the color of the surrounding slope, rendering the TECCO® System virtually invisible.
The Park Service intends on allowing the slope to revegetate naturally, which may take some time due to the elevation (10,000 ft), and the slow growth of the natural vegetation. However, seeds of the natural vegetation were gathered by the Park Service in the event reseeding may be required.
Due to the remote location and the short construction season, availability of materials, powder coating, and delivery were of major concern to the contractor and project owner. The TECCO® System and associated components were easily delivered in a timely manner to meet the construction schedule.
Approximately 500 grouted anchors were drilled and the TECCO® System was placed to stabilize the slope and prevent further raveling of rock.
The project was conducted and completed in the spring / summer of 2016.