About the Denver Basin
The Denver Basin aquifers are a series of layered bedrock aquifers containing usable groundwater. A map showing the extent of the Denver Basin aquifers is accessible in the links section below.
Denver Basin Description
The Denver Basin is a unique geologic formation along the Front Range reaching generally from Greeley on the north to Colorado Springs on the south, and from the Foothills on the west to Limon on the east. The Denver Basin is composed of bedrock aquifers, or water bearing formations, that lie one on top of the other in layers. The aquifers in the Denver Basin are called, progressing from top to bottom, the Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers. Northern portions of the Dawson and Arapahoe aquifers are differentiated into Upper and Lower aquifers. Between each aquifer there is a confining layer that isolates the individual aquifers from each other. Because of the nature of the confining layers and because of the limited connection between these aquifers and surface water, the groundwater in the aquifers is not renewable. When the groundwater is used, it is being “mined” or used up without any replacement.
Denver Basin Groundwater Rights
A landowner, or a party to which the underlying water right has been conveyed, may claim a right to withdraw and use groundwater from the Denver Basin bedrock aquifers underlying the land. A legal and administrative history of groundwater rights in the Denver Basin is given below. The following discussion provides references to the Colorado Revised Statutes (C.R.S.).
- Prior to 1973 withdrawal of Denver Basin groundwater was limited primarily by an assessment of proximity to other groundwater appropriations in the same aquifer. A party could, therefore, appropriate large quantities of groundwater from an aquifer regardless of the amount of land that party owned.
- In 1973 the state legislature created provisions for determining the amount of water that a party could claim and withdraw from the Denver Basin aquifers. As a result of Senate Bill 213, effective July 6, 1973 [sections 37-90-137(4) and 37-90-107(7), C.R.S.], a landowner, or a party to which the water right underling the land has been conveyed, is limited to withdrawing only that water determined to be underlying the land. Additionally, Senate Bill 213 limited withdrawals on the basis of an aquifer life of one hundred years, which is administered by limiting average annual withdrawals to one percent of the volume of water that is determined to be available underlying the land.
- In 1985 Senate Bill 5 provided a new framework to guide the appropriation of this groundwater. As required by Senate Bill 5 the State Engineer (the Director of the Colorado Division of Water Resources) adopted Rules in 1986 to carry out the provisions of this act. Senate Bill 5 and the associated rules identify locations within each aquifer where the withdrawal of groundwater has a minimal effect (below a statutory threshold) on the surface water system. The groundwater with this characteristic is legally identified as nontributary groundwater. Nontributary groundwater may be withdrawn and used without developing a plan for mitigating effects to the surface water system. Groundwater in locations where the withdrawal would result in a greater than the minimal effect on the surface water system is identified as not-nontributary groundwater, the withdrawal of which requires a plan to mitigate the effects on the surface water system.
Using Senate Bill 5 and the associated rules, along with other state statutes, the Division of Water Resources (DWR) and the Water Courts in Water Divisions 1 and 2 identify the amount of water available for withdrawal by an applicant, and the nontributary or not-nontributary status of the water. The premises of the quantity of groundwater available based on the amount underlying the land and limiting annual withdrawals to one percent of the total amount are also used to allow the uses permitted for many exempt well permits issued for individual on-lot wells that use Denver Basin groundwater.
Those portions of the Denver Basin aquifers lying within the Designated Groundwater Basins are administered by the Colorado Ground Water Commission separately from water rights outside of the Designated Basins in accordance with Designated Groundwater Basin statutes and rules, which are similar in concept to the statutory and administrative scheme used outside of the Designated Groundwater Basins. Information on the Designated Basins is accessible via the links section below.
Obtaining Denver Basin Groundwater Rights
Outside of the Designated Groundwater Basins state law [Section 37-92-302(1)(a), C.R.S.] allows a landowner, or a party to which the water right underlying the land has been conveyed, to apply to the Water Court for a determination of water right from the Denver Basin aquifers underlying the land. If the land is located in the South Platte River Basin, the Division 1 Water Court in Greeley will do the determination. If the land lies in the Arkansas River Basin, the Division 2 Water Court in Pueblo will do the determination.
Outside of the Designated Groundwater Basins state law [Section 37-90-137(4), C.R.S.] allows a landowner, or a party to which the water right underlying the land has been conveyed, to apply to the State Engineer for a well permit to withdraw water from the Denver Basin aquifers.
If land lies within the Designated Groundwater Basins, the right to withdraw the groundwater underlying the land must be applied for to, and determined by, the Colorado Ground Water Commission. Information on the Designated Basins is accessible via the links section below.
Responsibility of the Division of Water Resources
Applications for a Water Right to the Division 1 or 2 Water Court
When a party applies to the Water Court to adjudicate Denver Basin groundwater, the Division of Water Resources (DWR) has two primary responsibilities. First, representatives of DWR are required to file a consultation report with the Water Court [section 37-92-302(4), C.R.S.]. This report to the water court will state the concerns that DWR has with the application for water rights and advise the applicant as to the issues that must be addressed in the application. If the representatives of DWR feel that there are significant issues in the application and that significant changes must be made, the State Engineer may file a Statement of Opposition to the water court application [section 37-92-302(1)(b), C.R.S.].
Second, DWR will file its Determination of Facts report to the water court [section 37-92-302(2)(a), C.R.S.]. This report will provide the court with DWR’s position on important aspects of the requested water right including amount of water legally available from each aquifer, existing appropriations, nontributary vs. not-nontributary status, and depths to the aquifers. The Determination of Facts report is presumptive on the water court, which means that the information is presumed to be the best information available unless rebutted by other parties [section 37-92-305(6)(b), C.R.S.]. After considering all responses, the water court will then act on the application.
Applications for a Well Permit to the State Engineer
A landowner, or party to which the underlying water right has been conveyed, may apply to the State Engineer for a well permit to withdraw groundwater from a Denver Basin aquifer that has or has not been issued a decree from the Water Court. If a decree has been granted, then the evaluation of a well permit application is primarily a matter of ensuring that the groundwater will be withdrawn and used in a manner consistent with the decree. If a decree has not been granted, then the well permit application will be evaluated in accordance with applicable state statutes, rules and policies of the State Engineer.