WINDY GAP BYPASS – Letter to Legislators
Windy Gap Reservoir, a shallow impoundment that stalls the flow of the Colorado River near Granby, Colorado, has severely impaired the river’s health by filling its depleted waters with whirling disease spores, algae, thermal pollution, and silt. A bypass around Windy Gap Reservoir is needed to repair the cumulative ecological damage caused by more than a century of water development near the source of the Southwest’s most important river.
Construction of the Grand Ditch in the 1890s in what is now Rocky Mountain National Park ushered in an era of major transbasin diversions that reshaped the state of Colorado’s economy and ecology. These projects redirected water from the Colorado River headwaters of the West Slope across the Continental Divide to the cities and farms of the East Slope. The Moffat Water Tunnel, funded by federal New Deal money, began delivering water to Denver in 1936. Congress authorized the Colorado-Big Thompson (C-BT) Project in 1938 during the Dust Bowl and the Great Depression to provide supplemental irrigation water to farms on Colorado’s drought-prone northeastern plains. The C-BT Project, which also required federal funding to construct, continued the massive redistribution of Colorado River water across the Continental Divide.
This movement of water across mountain ranges is legal under Colorado water law. Based on the doctrine of prior appropriation, or “first in time, first in right,” Colorado water law allows for water to be diverted from its basin of origin to any place in the state where it can be put to beneficial use by agriculture, industry, and cities.
Before Congress could authorize the C-BT Project, a compromise had to be reached between Colorado’s West Slope and East Slope. As stated in Senate Document 80, Green Mountain Reservoir on the Blue River was created to compensate the West Slope for Colorado River water diverted to the East Slope. The impetus for Green Mountain Reservoir’s compensatory storage was protecting West Slope water rights—not protecting the ecology of the upper Colorado River.
The C-BT Project diverts water from the Colorado River above Windy Gap Dam; not until some thirty miles downstream of Windy Gap does the stored water of Green Mountain Reservoir reinvigorate the Colorado’s depleted flow. Not only does Northern Water’s C-BT Project divert flow from the Colorado River, but also Denver Water’s Moffat Tunnel diverts a significant amount of the native flow of the Fraser River and its tributaries, further diminishing the volume of the Colorado River headwaters.
When the Bureau of Reclamation completed the C-BT Project in 1957, the largest transbasin diversion in the state redirected the Colorado River headwaters through the Adams Tunnel to the East Slope, bolstering agriculture in northeastern Colorado. During the ensuing decades, as the state’s population expanded, the transformation of farmland into towns and cities along the northern Front Range was made possible by converting water delivered by the C-BT Project from agricultural ownership to urban use.
The Windy Gap Project, completed in 1985, was piggybacked on the C-BT Project’s infrastructure. The Windy Gap Project was intended to divert more flow from the Colorado River headwaters to cities facing explosive population growth in Boulder, Larimer, and Weld counties, but the project had unintended consequences. Complex conflicts over water rights prevented the project from diverting a “firm yield” of water, meaning the growing urban areas of the northern Front Range could not rely on a steady supply of water delivered by the Windy Gap Project. The other unintended effect of this project was its harmful impact on the health of the Colorado River downstream of Windy Gap Dam.
As documented in a 2011 Colorado Division of Wildlife study and a 2015 report prepared by Tetra Tech for the Colorado Department of Natural Resources and the Municipal Subdistrict of Northern Colorado Water Conservancy District, Windy Gap Reservoir exacerbates the damaging effects of the Colorado River’s diminished volume. The mottled sculpin, a fish species native to the Colorado River Basin, and 38 percent of native aquatic insect species have been extirpated downstream of Windy Gap Dam due to sedimentation of the streambed caused by Windy Gap Reservoir and depleted streamflows. The loss of these species has rippled throughout the aquatic ecosystem, devastating one of the West’s premier Gold Medal trout fisheries.
The proposed Windy Gap Firming Project will “firm” the yield of water diverted at Windy Gap, further decreasing the volume of the already heavily depleted upper Colorado River. If Northern Water’s Windy Gap Firming Project and Denver Water’s Moffat Collection System Project proceed as planned, some 80 percent of the native annual flows of the Colorado River headwaters will be diverted to the Front Range. To enhance the degraded river and mitigate the effects of future diversions, a bypass must be built around Windy Gap Reservoir, as detailed in the 2015 Tetra Tech report. This bypass will take Windy Gap Reservoir off-stream, helping reverse environmental damage to the river below Windy Gap Dam. The bypass will improve sediment transport, reduce elevated stream temperatures, restore the connectivity of the river, and improve aquatic habitat. The bypass will help heal the damaged headwaters of the state’s namesake river—a national treasure that defines the American Southwest.
The federal government financed Denver Water’s Moffat Tunnel and Northern Water’s Colorado-Big Thompson Project; landowners along the reach of the Colorado River harmed by these projects are now requesting that the federal government help finance the bypass to restore the damaged river. To build the bypass, approximately $9.6 million is required. State agencies have pledged $4 million; $5.6 million is needed from the federal government.
Building the Windy Gap bypass presents a rare opportunity to hand off to the next generation a river in better health than its deteriorated condition of past decades. A restored headwaters reach of the iconic Colorado River will pay dividends far into the future. For a relatively modest financial investment, American taxpayers will receive a revived natural resource of incalculable value.
Construction of the Grand Ditch in the 1890s in what is now Rocky Mountain National Park ushered in an era of major transbasin diversions that reshaped the state of Colorado’s economy and ecology. These projects redirected water from the Colorado River headwaters of the West Slope across the Continental Divide to the cities and farms of the East Slope. The Moffat Water Tunnel, funded by federal New Deal money, began delivering water to Denver in 1936. Congress authorized the Colorado-Big Thompson (C-BT) Project in 1938 during the Dust Bowl and the Great Depression to provide supplemental irrigation water to farms on Colorado’s drought-prone northeastern plains. The C-BT Project, which also required federal funding to construct, continued the massive redistribution of Colorado River water across the Continental Divide.
This movement of water across mountain ranges is legal under Colorado water law. Based on the doctrine of prior appropriation, or “first in time, first in right,” Colorado water law allows for water to be diverted from its basin of origin to any place in the state where it can be put to beneficial use by agriculture, industry, and cities.
Before Congress could authorize the C-BT Project, a compromise had to be reached between Colorado’s West Slope and East Slope. As stated in Senate Document 80, Green Mountain Reservoir on the Blue River was created to compensate the West Slope for Colorado River water diverted to the East Slope. The impetus for Green Mountain Reservoir’s compensatory storage was protecting West Slope water rights—not protecting the ecology of the upper Colorado River.
The C-BT Project diverts water from the Colorado River above Windy Gap Dam; not until some thirty miles downstream of Windy Gap does the stored water of Green Mountain Reservoir reinvigorate the Colorado’s depleted flow. Not only does Northern Water’s C-BT Project divert flow from the Colorado River, but also Denver Water’s Moffat Tunnel diverts a significant amount of the native flow of the Fraser River and its tributaries, further diminishing the volume of the Colorado River headwaters.
When the Bureau of Reclamation completed the C-BT Project in 1957, the largest transbasin diversion in the state redirected the Colorado River headwaters through the Adams Tunnel to the East Slope, bolstering agriculture in northeastern Colorado. During the ensuing decades, as the state’s population expanded, the transformation of farmland into towns and cities along the northern Front Range was made possible by converting water delivered by the C-BT Project from agricultural ownership to urban use.
The Windy Gap Project, completed in 1985, was piggybacked on the C-BT Project’s infrastructure. The Windy Gap Project was intended to divert more flow from the Colorado River headwaters to cities facing explosive population growth in Boulder, Larimer, and Weld counties, but the project had unintended consequences. Complex conflicts over water rights prevented the project from diverting a “firm yield” of water, meaning the growing urban areas of the northern Front Range could not rely on a steady supply of water delivered by the Windy Gap Project. The other unintended effect of this project was its harmful impact on the health of the Colorado River downstream of Windy Gap Dam.
As documented in a 2011 Colorado Division of Wildlife study and a 2015 report prepared by Tetra Tech for the Colorado Department of Natural Resources and the Municipal Subdistrict of Northern Colorado Water Conservancy District, Windy Gap Reservoir exacerbates the damaging effects of the Colorado River’s diminished volume. The mottled sculpin, a fish species native to the Colorado River Basin, and 38 percent of native aquatic insect species have been extirpated downstream of Windy Gap Dam due to sedimentation of the streambed caused by Windy Gap Reservoir and depleted streamflows. The loss of these species has rippled throughout the aquatic ecosystem, devastating one of the West’s premier Gold Medal trout fisheries.
The proposed Windy Gap Firming Project will “firm” the yield of water diverted at Windy Gap, further decreasing the volume of the already heavily depleted upper Colorado River. If Northern Water’s Windy Gap Firming Project and Denver Water’s Moffat Collection System Project proceed as planned, some 80 percent of the native annual flows of the Colorado River headwaters will be diverted to the Front Range. To enhance the degraded river and mitigate the effects of future diversions, a bypass must be built around Windy Gap Reservoir, as detailed in the 2015 Tetra Tech report. This bypass will take Windy Gap Reservoir off-stream, helping reverse environmental damage to the river below Windy Gap Dam. The bypass will improve sediment transport, reduce elevated stream temperatures, restore the connectivity of the river, and improve aquatic habitat. The bypass will help heal the damaged headwaters of the state’s namesake river—a national treasure that defines the American Southwest.
The federal government financed Denver Water’s Moffat Tunnel and Northern Water’s Colorado-Big Thompson Project; landowners along the reach of the Colorado River harmed by these projects are now requesting that the federal government help finance the bypass to restore the damaged river. To build the bypass, approximately $9.6 million is required. State agencies have pledged $4 million; $5.6 million is needed from the federal government.
Building the Windy Gap bypass presents a rare opportunity to hand off to the next generation a river in better health than its deteriorated condition of past decades. A restored headwaters reach of the iconic Colorado River will pay dividends far into the future. For a relatively modest financial investment, American taxpayers will receive a revived natural resource of incalculable value.
