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The Denver Basin is a series of layered aquifers that underlie portions of the following counties: Weld, Boulder, Adams, Denver, Morgan, Arapahoe, Douglas, Elbert, and El Paso.  From top to bottom, the aquifers are named the Dawson, Denver, Arapahoe, and Laramie-Fox Hills.  Property owners that own land within the Denver Basin can often take advantage of non-tributary water that may be in one of the aquifers below their property.   The non-tributary water in the Denver Basin can be used for any purpose (without a requirement for replacement water) so long as annual pumping is set at 1%, or less, of the total quantification of water in that aquifer.  This value is set in state law so that the aquifer will last for at least 100 years.  (Some counties have a stricter rule requiring the aquifer to last for a longer period.)  For example, if a quantification of water in the aquifer for a given parcel is 500 acre-feet, then the property owner may pump 5 acre-feet per year and use the water for any use.   Developers may use this non-tributary water as their water source for housing developments and subdivisions. 

Unfortunately, the non-tributary aquifers are typically the deepest aquifers, which makes them the most expensive to drill into.  However, a plan for augmentation can be set up that will allow the property owner to drill into and pump from the upper not non-tributary aquifers and reserve the non-tributary water for future replacements.   A Water Resource Engineer will be required to analyze the aquifer at the given location for development of the plan for augmentation.  The engineer will quantify the amount of water in the aquifers and model the pumping of the aquifer to determine the streams that will be impacted and the amount of annual depletions to those streams.  Often the depletions are spread out far into the future, and it can be shown that during the life of the plan the septic system and lawn irrigation return flows are enough to offset all river depletions.  These plans are typically set up for 100 years, or longer depending on the county where the parcel is located.  In this type of plan, the developer will not be required to purchase any replacement water or make any replacements during the life of the plan.  The engineer will ensure that the property owner has enough non-tributary water in the deep aquifers to offset the post-plan depletions, and the property owner must agree to assign this non-tributary water to be used to replace those future depletions when the plan ends.

The typical exempt type well permit can also be issued in the Denver Basin, for any aquifer, if the applicant qualifies for an exempt well permit.  Well permits can also be issued for non-tributary ground water for any beneficial use (even if the applicant can not qualify for an exempt well permit), without a requirement for replacement water, for 1% of the quantification as described above.  A decreed water right is not required for these cases, and the property owner can apply directly to the Division of Water Resources for a well permit.

To obtain a water right for the Denver Basin ground water, the property owner must file for a new water right in water court.  After a water right is decreed, the property owner may sell the water right, or he may sell the property and retain the water right.  A plan for augmentation, as described above, must also be decreed in water court.  Therefore, a property owner that desires to adjudicate his Denver Basin ground water or operate a plan for augmentation with Denver Basin water should hire a water rights attorney and a water resources engineer to help him through this process.

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