What Is a Safe Yield Calculation with Respect to Groundwater?

A safe yield calculation is designed to ensure an adequate water supply within an aquifer. When an applicant applies for a new water right, a safe yield calculation is made by the applicable governing body. This may be the Division of Water Resources or the local groundwater management district.

The safe yield calculation takes into account all the wells in the vicinity of the proposed water right, the saturated thickness of the aquifer, and other factors. A mathematical formula may be used to ensure that adequate water exists in a given location. If the water right satisfies the safe yield calculation, then the applicant may proceed with the next steps in obtaining a water right.

If the water right violates a safe yield calculation, the applicant can still seek a waiver from the local governing body. If the waiver is not granted, the applicant likely can proceed with obtaining the water right. If a waiver is allowed, the applicant can pursue next steps in the process.

Safe yield calculations are a more recent requirement in the grand scheme of Kansas water law. Thus, unfortunately, many portions of aquifers in Kansas are highly over-appropriated. Safe yield calculations are thus vital to protecting water resources.

How Does the Division of Water Resources Determine Whether to Grant a New Water Right?

The Chief Engineer of the Kansas Division of Water Resources must constantly balance the public interest with the goal of allowing water to be allocated to a beneficial use. Thus, there is a constant tension between development, on one end of the spectrum, and the preservation of water as a scarce resource, on the other end of the spectrum. 

Consequently, the Chief Engineer must consider a variety of factors in deliberating on whether to grant a new water right. The Chief Engineer should first evaluate if there is water available for appropriation. In many areas, this is done through a safe yield calculation. In a groundwater management district, the manager of the respective district usually helps with this calculation. 

It is critical for the Chief Engineer to develop an understanding of whether granting the new water right will impair existing water rights. Kansas statutes define the tolerance for “impairment” as “beyond a reasonable economic limit.” This standard has been developed because many areas are already highly appropriated, and, in the case of the Ogallala Aquifer, the continued source of supply may be limited.

The Chief Engineer must also consider whether the granting of the new water right is in the public interest. In making this determination, the Chief Engineer will look at factors such as the minimum desirable streamflows, the nature of the local water supply, prior water rights granted, and other relevant factors.   The Chief Engineer can even add water quality into the calculus. For example, in the Equus Beds Aquifer, there is a saltwater plume that the Chief Engineer will likely seek to keep from spreading in determining whether to grant new water rights.

Frankly, it has become increasingly more difficult to obtain a water right. Most places in Kansas are, simply put, over-appropriated. However, if you are fortunate enough to be located in an area where you believe water is available for appropriation, the above discussion should help illuminate whether the Chief Engineer will issue a permit.

Potential Changes Looming for Recharge Credits in Equus Beds

The City of Wichita has filed applications with the Division of Water Resources to change the manner in which the city is granted “recharge credits” arising from the aquifer recharge project in the Equus Beds aquifer. The recharge project takes water from the Little Arkansas river during the times when the river is flowing at a specified rate above normal.  The water is treated to normal drinking water standards and is caused to be either injected or settled into the aquifer. The city’s stated purpose is to provide increased access to Equus Beds water during times of draught. The city already has the most extensive water rights in the Equus Beds aquifer.  The Division will hold public hearings to consider the applications.