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Kansas Geological Survey, Open-file Report 2015-33


West Central Kansas GMD1 Model

Kansas Water Office Contract 14-116

by
Brownie Wilson, Gaisheng Liu, Geoff Bohling, Donald Whittemore, and James Butler, Jr.

KGS Open File Report 2015-33
Funded by the Kansas Water Office (Kansas Water Plan) and
Western Kansas Groundwater Management District #1
Nov. 2015

Introduction

Western Kansas Groundwater Management District No. 1 (GMD1) was formally established in 1973 and was the first of five such local management districts in Kansas authorized under the Groundwater Management District Act of 1972. Overlying portions of five counties in west- central Kansas, GMD1's official purpose is to promote the better use of groundwater, collect and disseminate research information, and work congruently for better water management.

GMD1 was one of the first areas developed for groundwater in Kansas with the first irrigation well being drilled in 1907. As such, it has one of the largest densities of vested water rights, those that precede the 1945 Kansas Water Appropriation Act, in the state. The Ogallala portion of the High Plains aquifer (HPA) is the primary water source for virtually all water uses. Like much of western Kansas, GMD1 has experienced declining water tables and reductions in historically limited streamflows. Today, most of the district contains fewer than 40 ft of saturated thickness. However, there are two areas where the thickness of the Ogallala is at or more than 100 ft. One area is in the southern portion of Wallace County, and the other is in a north-south trending trough in Scott County.

Project Objective

The Kansas Water Office (KWO) and GMD1 contracted with the Kansas Geological Survey (KGS) in January of 2013 to develop a numerical groundwater model for the GMD1 area. The primary objective of the model is to better understand the hydrologic system and water table changes occurring in the underlying HPA. The model will be used to simulate future water use and management scenarios to estimate their effects on the HPA in this region.

The project period covered January 2013 through the summer of 2015. The calibrated transient model was completed in July 2015. This final report was completed in August 2015.

Model Oversight

As part of the model development process, GMD1 formed a Model Advisory Committee (MAC) to oversee the initial phases of the project. The MAC met approximately three times a year in Scott City, and the meetings included conference calls and Internet-based PowerPoint presentations viewed by all individuals invited to the meeting. Members of the MAC included staff from the KWO, the Topeka/Manhattan headquarters and Garden City field office of the Kansas Department of Agriculture, Division of Water Resources (KDA-DWR), GMD1 manager and board members, and several individual members of the district representing irrigation and municipal water supply interests. During the model's development, several agencies had key staffing changes, specifically the GMD1 manager and KWO's primary point of contact for the project.

The KGS presented updates throughout the model's creation at various county-based meetings, GMD1's annual meetings, the Governor's 50 Year Water Vision meetings, and regular GMD1 board meetings. The KGS made the final model available for review to the KDA-DWR.

The complete text of this report is available as an Adobe Acrobat PDF file.

Read the PDF version (43 MB)

Recalibrated GMD1 Model based on lithologic- and water-balance-based specific yields. In the summer of 2020, the GMD1 model was recalibrated using specific yield (SY) values based on lithologic- and water-balance-based methods that are derived from relationships between pumping and water-level change in three unique lithology areas; sands and gravels (Wallace County); sands (Wichita County); and clays and silts (Wallace and Greeley counties). This data-driven approach computes SY values that are much smaller than traditional estimates but significantly improves the regional groundwater model simulated responses to future water management scenarios.

Spreadsheet of Lithology-based, water use and water-level change data

Spreadsheet of individual well records

Liu, G., Wilson, B. B., Bohling, G. G., Whittemore, D. O., Butler, J. J., Jr., 2020, Specific yield in regional groundwater modeling: pitfalls, ramifications, and a promising path forward, Water Resources Research, In Review, 35 p. Link coming soon.


Kansas Geological Survey, Geohydrology
Placed online Nov. 9, 2015
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