Grand River Ditch
|Nearest city||Grand Lake, Colorado|
|Area||460 acres (190 ha)|
|MPS||Rocky Mountain National Park MRA (AD)|
|NRHP Reference #||76000218|
|Added to NRHP||September 29, 1976|
The Grand Ditch, also known as the Grand River Ditch and originally known as the North Grand River Ditch, is a water diversion project in the Never Summer Mountains, in northern Colorado (United States). It is 14.3 miles (23.0 km) long, 20 feet (6.1 m) wide, and 3 feet (0.91 m) deep on average. Streams and creeks that flow from the highest peaks of the Never Summer Mountains are diverted into the ditch, which flows over the Continental Divide at La Poudre Pass at 10,175 feet (3,101 m), delivering the water into the Cache La Poudre River for eastern plains farmers. The ditch was started in 1890 and wasn't completed until 1936. The ditch diverts between 20 to 40% of the runoff from the Never Summer Mountains, and delivers an average of 20,000 acre feet (25,000,000 m3). It significantly impacts the ecology in the valley below and the National Park Service has fought in court to reduce the amount of diverted water.
The Grand Ditch was built by the Larimer County Ditch Company, mostly by Japanese crews, working with hand tools and black powder. The first diverted water flowed east across La Poudre Pass on October 15, 1890. Water Supply and Storage Company took over ownership in 1891. The ditch was extended every year, and reached three miles in 1894.
After the creation of Rocky Mountain National Park, increasing demand for water led to the creation of Long Draw Reservoir, and the required land was taken away from the park in 1923. Long Draw reservoir opened in 1930. The Grand Ditch was then lengthened one more time—this required an act of Congress since it was now in a national park—to 14.3 miles (23.0 km) in September 1936.
In May 2003 a 100 foot section of the ditch breached about 2.4 miles (3.9 km) south of La Poudre Pass, causing the water to cascade down the slopes and into the Colorado River. The flood left a visible scar on the mountainside. The Water Supply and Storage Company was ordered to pay $9 million in damages to Rocky Mountain National Park.
- National Register of Historic Places listings in Grand County, Colorado
- The Colorado-Big Thompson Project, a 1930s tunnel project for diverting Colorado River waters in the same area
- "National Register Information System". National Register of Historic Places. National Park Service. 2010-07-09.
- Effects of the Grand Ditch, National Park Services, 2004. http://www.nps.gov/romo/downloads/CDRLC/summaries/ditch.pdf
- Water across the Divide, in High Country News, October 12, 2009, http://www.hcn.org/issues/41.17/water-across-the-divide
- Perry, Phyllis J., It Happened in Rocky Mountain National Park, Globe Pequot, 2008 ISBN 978-0-7627-4238-7
- Grand Ditch settlement reached: $9 million, in Ft Collins Now, 5 May 2008, http://www.fortcollinsnow.com/article/20080505/NEWS/911660996&parentprofile=search
- Historic American Engineering Record (HAER) No. CO-32, "Grand Ditch, Baker Creek to LaPoudre Pass Creek, Grand Lake vicinity, Grand County, CO"