With Colorado’s water year at its mid-July end and many Northern Colorado reservoirs still flush with the bounty of a plentiful water year, water woes of years past have turned into discussions of how the state will store water in the future.
In the coming months, the Army Corps of Engineers will release an updated study on the Northern Water Conservancy District’s proposal to expand its water storage capacity near Fort Collins. The Northern Integrated Supply Project would build Glade Reservoir northwest of the city, bringing a new reservoir larger than Horsetooth Reservoir to the area.
Before the release of the study reignites the battle over the potential environmental impacts of expanding Northern Colorado’s water storage capacity, we look at where Fort Collins gets the water that provides the basis for everything from the natural resources residents enjoy to the craft beer they drink…
Before the High Park Fire, which burned more than 87,000 acres of the Poudre watershed, Fort Collins Utilities split its water sources between the project and the river. But the Poudre’s water has since become filled with fire and flood debris, which prompted a total shutdown of river water for Fort Collins customers.
Time and the September 2013 floods have cleaned out the river, but the city is still mostly reliant on the C-BT project for more than 60 percent of its water each year.
Fundamentally, snowmelt fills the many reservoirs in the C-BT project. The Northern Colorado Water Conservancy District, which helps manage the project, delivers a certain amount of water to cities like Fort Collins as well as farmers and irrigators — all of whom own hundreds or thousands of acre-feet of the project’s water…
Here’s a look at where our water comes from.
THE WESTERN SLOPE
The water that feeds Colorado — and a vast swath of the nation — begins its downward flow from the Continental Divide high in the Rocky Mountains. In order to harness water that otherwise would flow to the Pacific Ocean, water managers created a vast network of reservoirs, tunnels and canals to reroute Western Slope water to Colorado’s more populous Front Range.
For Fort Collins, and much of the northern Front Range, this is where it all begins. Snowmelt fills this Western Slope reservoir, and the water from it is pumped to Shadow Mountain Reservoir. From there, it’s literally all downhill — gravity pushes water through five reservoirs until it gets to Horsetooth Reservoir, southwest of Fort Collins. This year, due to above-average snowpack, Lake Granby soon will spill over its banks. It can hold up to 540,000 acre-feet of water.
Horsetooth was built along with the Colorado-Big Thompson Project and is a fraction of the size of Lake Granby — it holds about 156,000 acre-feet of water. This is where Fort Collins will get most of its C-BT water, which has traveled through the 13-mile Adams Tunnel, under U.S. Highway 34, and through several reservoirs. Fort Collins Utilities has its only operational water treatment plant at Horsetooth. In 2014, Fort Collins gets about 65 percent of its water from the C-BT project.
THE CACHE LA POUDRE RIVER
The Poudre River typically provides Fort Collins with 50 percent of its water. But after the High Park Fire polluted the river, Fort Collins has been forced to shut down its Poudre River sources, sometimes for months. The upper part of the river is considered “wild and scenic” — a federal designation. It is also one of the few remaining dam-free rivers in Colorado. In 2014, Fort Collins gets about 35 percent of its water from the Poudre.
Carter Lake is one of many reservoirs that make up the Colorado-Big Thompson Project. Some of Fort Collins’ water can come from this reservoir, but not frequently. Other reservoirs in the system include Grand Lake, Mary’s Lake, Lake Estes and Flatiron Reservoir, to name just a few.
Treated water coming into Fort Collins comes from a plant near Horsetooth Reservoir. Since Nov. 1, the city has used about 9,700 acre-feet of water from the Colorado-Big Thompson Project, and about 5,200 acre-feet from the Poudre River. Before the High Park Fire, the city typically split its water use between the two sources but has since had to use more C-BT water.