David Ganje: Aquifers – out of sight and out of mind?

David Ganje
Special to the Farm Forum
David Ganje, Rapid City

The state is in a quandary over an unresolved water-use permit application.

This interesting permit application is for water use as part of an agricultural irrigation system. The application consists of a water draw (the technical term is a water diversion) for groundwater from a little known and little used aquifer in southeast South Dakota. One rarely runs into this particular aquifer in one’s travels.

The state is the trustee of the public waters of the state including groundwater located within the state’s jurisdiction. This means the government of the state of South Dakota manages the right to use public waters.

The permit application we here discuss is still pending even though it was originally filed with the state on January 10th, 2022. The requested irrigation use is not for a large acreage but the challenges for the state have to do with the strong diversion rate requested. The application calls for a diversion rate of over 1 cfs for 70 acres.

Cubic feet per second (CFS) is a common unit for the quantity of water flowing from a water source. The permit application under discussion is requesting a diversion rate greater than the statutory limit of 1 cfs per 70 acres due to the method of irrigation. 1 cubic foot per second = 7.4805 gallons flowing by a particular point in 1 second. So, what’s going on here? Let’s unwrap this.

The South Dakota Niobrara aquifer is a secondary aquifer in the state which consists of marine shale, chalk, marl, and chalky limestone of the Niobrara Formation. Most well yields from the Niobrara are sufficient only for domestic use, but some ag use is noted in state records. Water drawn from it can be utilized for irrigation purposes but not in large quantities.

No studies have been done to estimate the recharge rate to the Niobrara aquifer in South Dakota. The aquifer does contain existing state managed observation wells. The observation well data shows, over the period of record, recharge is greater than discharge. Water levels in the observation wells monitoring the aquifer generally rise during wet periods and decline to stable levels during drier periods.

For a sustainable system the amount of water withdrawn from an aquifer should be balanced with the amount of water returned (recharged) by nature to that aquifer. Recharge of the Niobrara aquifer near the permit application site is likely from groundwater inflow from adjacent or overlying aquifers due to leakage from these hydrologically connected aquifers.

The state in this application did not reject the applicant and in fact in its report paperwork stated, “. . . there is a reasonable probability that unappropriated water is available from this portion of the Niobrara aquifer for the proposed appropriation [meaning the applicant’s permit application].”

Why the quandary? No studies have been done to estimate the recharge rate to the Niobrara aquifer. And no test hole or water-well completion report was submitted with the application. This means the functionality of the aquifer is unknown.

To exacerbate the unknown the state also reported an additional investigation is needed to determine if the existing high-capacity irrigation wells in the area are unlawfully impairing domestic users. The state wants to investigate an unlawful impairment complaint which might find that under high use conditions unlawful water use is occurring resulting in an unacceptable drawdown of the aquifer quantity.

The authority given to government does not necessarily result in secure and comfortable decision making, but rather more often hands government a dilemma. In this permit application case, the Water Management Board approved a motion to defer (delay) a decision on the permit application for up to 2 years. The state DANR as a part of the deferral wanted to coordinate with the South Dakota Geological Survey to install three additional new observation wells in the area.

David Ganje is an attorney who practices natural resources, environmental and commercial law. Contact him at