Compiled by the Black Forest Water & Wells Committee August 2021
(scroll down to the end to download a printable version)
The Denver Basin is a giant bowl reaching from Greeley in the north to Colorado Springs in the south The basin extends from the front range out to Limon The basin is actually four bowls inside each other representing four separate aquifers The aquifers are the Dawson (top,) Denver, Arapahoe and Laramie-Fox Hills (bottom.) State water officials believe the four aquifers are sealed from each other However, tests in one area from an Arapahoe well affected the adjacent Denver and Dawson aquifer No one knows for sure how much the aquifers are sealed from each other Drilling logs do not show a clear, impermeable boundary between aquifers If these bowls are being recharged at all, it is a slow process over generations of time Only a little over half of the Denver Basin water can be economically removed Through continuous, long-term use, a well becomes less and less efficient After several years, it is not economical to pump because of decreasing output A local well-driller with 30 years of experience presented a program about wells in the Denver Basin He said the geology of the Denver Basin is not unified or homogeneous Basin has multiple interlocking and overlapping layers of sand, gravel, sandstone and claystone Wells 1/4 mile apart can produce widely varying amounts of water Wells only 200 feet apart can have widely different static levels Having a water allocation or water right is no guarantee of predicted amount of water in that area “Paper water does not equate to wet water”
Statewide, agriculture accounts for 86% of the water used in Colorado Water use from Denver Basin is 62% agriculture, 20% municipal and 12% domestic (private wells) Water rights all across the state have been sold to developers and municipalities These water rights include both underground water and water from rain and snow runoff The water in Colorado rivers all belongs to someone with water rights Some of the water in the Colorado River belongs to states like Arizona and Utah When water rights are sold, farm land is idle and unused because of arid conditions and no irrigation Over 45,000 acres along the Arkansas River are now idle under the “buy and dry” principle The water for these rights can be used upstream in Pueblo and beyond For water use, the “use it or lose it” rule sometimes causes water waste If water is not used, water not owned by a water right can be given to another user Another user may claim he can put the water to better use Water that is owned is sometimes “used” by pouring it out on the ground so no one else can claim it
For the water that falls out of the sky, 70% evaporates back into the atmosphere and 30% soaks into the ground and runs off into streams, rivers and the ocean.
For residential households in the Black Forest, the State of Colorado considers water use as follows
An acre foot of water is 326,500 gallons which is 1 acre (about a football field) 1 foot deep in water The average household uses 0.35 acre-feet of water per year. This is 313 gallons per day. 90% of the water used in a household is returned into the ground via the septic system Just 10% is actually consumed or evaporated into the air 15% of the water used for watering gardens and lawns is returned into the ground 85% of irrigation water is evaporated into the air and not soaked into the ground 100% of the water used for animal watering is consumed and none is returned into the ground
Colorado Springs gets water from the Arkansas River and from snow runoff on the Western Slope Colorado Springs gets water that would otherwise run off into streams and then the Arkansas River Water is piped from the Western Slope through Twin Lakes near Buena Vista and then into Arkansas River A secondary pipeline comes over the front range just south of the Air Force Academy The Southern Delivery System (SDS) is a 24-inch waterline from Pueblo Reservoir to Colorado Springs At present, Colorado Springs Utilities has water rights and supplies above the current demand CSU also has extensive Denver Basin water rights CSU policy is not to use Denver Basin aquifer water except in an emergency Annexed developments surrender their water rights to CSU except for golf courses and ponds Flying Horse and Flying Horse North water their golf courses with aquifer water Wolf Ranch created Wolf Lake (6 acres) with aquifer water So far, Colorado Springs Utilities has not provided water to anyone outside the city limits The city is considering providing water to entities outside the city limits Providing water this way would be a revenue boost to Colorado Springs Utilities Colorado Springs uses 40 million gallons per day in the winter and 100 million gpd in the summer
Thousands of homeowners rely on Denver Basin water for their homes The Denver Basin has well over 100,000 wells, but the exact number is difficult to find in state documents El Paso County alone has over 22,000 private wells The suburb of Highlands Ranch in Denver (100,000 residents) uses Denver Basin water for 10% of its needs 70% of water used in the South Denver metro area is groundwater Castle Rock, Parker and other municipalities use Denver Basin water
Water levels in the Denver basin are declining in several areas Around the city of Castle Rock some wells have been declining up to 30 feet/year The Denver basin is thinner in the Castle Rock area The Castle Rock area has a huge number of Denver basin wells Fortunately, according to a local well driller, Black Forest wells have been holding quite steady for many years The Dawson aquifer is much thicker in the Black Forest area than further north
The State of Colorado Division of Water Resources allocates how much water anyone can pump The state has models that tell the thickness of the aquifer at any given location The decree takes the thickness of the aquifer (feet) times the acreage of the parcel = acre-feet This is called the saturated thickness The state considers 0.2 or 1/5 of each cubic foot to be water Calculated volume of water allowed per year is divided by 100 for 100-year duration of aquifer Figure is again divided by 3 for 300-year rule Amount of water allocated for pumping is based on 1985 geological model The amount is based on pumping the aquifers dry in 100 years The 100-year rule was initiated in 1973 We are 46 years, almost halfway, into the 100 years toward “dry” wells in many parts of the state
El Paso County initiated a 300-year rule in 1986 to extend available water for private wells in the county El Paso County approves only 1/3 of the state allocation per year Theoretically the 300-year rule should provide water for two more centuries The 300-year rule was challenged in the Colorado Supreme Court but was upheld for El Paso County In spite of the 300-year rule, all of the northern El Paso County water providers need more water Water providers were told they had enough water for their developments Continuous pumping is resulting in diminishing returns from well production Manager of Woodmoor Water says well that formerly pumped 100 gpm only pumps 40 gpm now Monument, Palmer Lake, Woodmoor, Tri-View, Meridian Ranch, Paint Brush Hills need more water Several have purchased additional water rights on ranches south of Colorado Springs and Leadville Access to that water not available at this time
Loop proposal suggested in late 2021 to pipe SDS water north through Cherokee Metro pipeline Cherokee Metro would get SDS water in exchange for CSU using Cherokee pipeline Cherokee wishes to be absorbed into CSU but high debt is stumbling block Pipeline would be extended from Sundance Ranch to Monument and Palmer Lake Renewable water would be provided to northern water providers to save Denver Basin water Wastewater would be piped south to connect to CSU wastewater system along I-25 Estimated cost around $134 million
Urban development south of Black Forest will potentially use huge amounts of Denver Basin water Sterling Ranch, The Retreat at TimberRidge and The Ranch will total 7400 homes The entire Black Forest has about 6600 homes with private wells by comparison These developments are currently planning to use Denver Basin water from the Black Forest Not enough groundwater exists under these developments to serve the high number of homes Water rights on Sundance Ranch, Flying Horse North, Bar-X Ranch and McCune Ranch purchased to provide more water A potential annexation plan may mean some of these developments will use city water Unintended consequence of annexation may be that developments will redesign to all urban lots More stringent development requirements in Colorado Springs city limits than for rural developments Developers are leapfrogging over Banning-Lewis Ranch because of stringent city requirements Resulting developments often use Denver Basin water instead of renewable city water
Cherokee Metropolitan District has obtained significant water rights in the Black Forest Sundance Ranch, Flying Horse North, Shiloh Ranch and County Line Road water rights were purchased State granted permission to pump 1246 acre-feet of Dawson water per year from 23 well sites Cherokee has permission to pump a total of 3708 acre-feet of water per year from all 4 aquifers Coupled with planned residential development, this is 10 times as much water use as for 5-acre lots All the well sites are on the property boundaries so half of the water pumped belongs to neighbors The water is being piped to supply 18,000 customers in southeast Colorado Springs Cherokee Metro has committed 2025 af/yr of water to Sterling Ranch This is 1.8 million gallons of water per day.
Cherokee Metro District wells already drilled are not producing significant water Only 4 wells have been drilled to date One Denver well drilled to 1970 feet (12-inch bore) and produced only 50 gpm One Arapahoe well drilled to 2520 feet (12-inch bore) and produced 450 gpm One Dawson well drilled to 1044 feet (12-inch bore) and produced 68 gpm A second Dawson well drilled to 1030 feet (12-inch bore) and produced 65 gpm The two Dawson wells do not even have a pump installed and are not producing These wells cost around $750,000 to drill Three of these four wells are producing very poorly These wells suggest that commercial extraction may not be productive or economical Transmissivity or flow of water back and forth underground may not be very rapid Clay and sandstone don’t allow water to flow laterally very easily Water seems to be located in “pockets” within clay and sandstone layers “Pockets” of water sufficient for private wells but not for commercial extraction Water seems to not flow back into large wells fast enough to produce profitable results This is an excellent example of “paper water may not equal real water.”
Falcon Area Water Authority (FAWA) is planning a huge water project in Black Forest Project will pipe water from 27 sites to Falcon and Sterling Ranch area Water coming from High Forest Ranch (7), Bar-X Ranch (16) and Winsome (4) sites Water rights granted for 1270 acre-feet/year to be pumped FAWA officials say more water rights are for sale in the Black Forest Remains to be seen if “paper water equals wet water”
Future Potential Uses of Denver Basin Water
A developer has obtained rights to 39,000 acre-feet of water per year from Greenland Ranch Greenland Ranch is a conservation easement on thousands of acres between Monument and Castle Rock This conservation easement will not be developed but remain as open space Front Range Water Company (Sun Resources) is proposing a 24-inch pipeline to Denver To put this in perspective, this is 35 million gallons of water per day they are allotted. This water would be pumped to an eastern Denver suburb
A water developer in Denver is proposing to pipe San Luis Valley water (Alamosa) to Denver The San Luis Valley is very arid, gets only a few inches of rain per year and is heavily irrigated All the water is appropriated so developer would have to buy water and dry up farm land Sean Tonner is leading a group that proposes to spend $118 million dollars for water They propose to buy 22,000 acre-feet of water that would dry up 10,000 acres of farm fields They propose to pay farmers to not plant crops and save another 30,000 acre-feet of water from irrigation That would dry up another 15,000 acres of farmland and leave it idle They want to sweeten the pie with a $50 million gift to the San Luis Valley farmers Plan involves a 200-mile pipeline to transport the water to Eleven Mile Reservoir and South Platte River
