The City of McPherson relied on the Equus Beds Aquifer as its critical source of water for commercial, industrial and municipal use.
In response to declining water levels in the aquifer, the McPherson Board of Public Utilities (BPU) sought an additional source of supply to supplement its local wellfield. The U.S. Bureau of Reclamation indicated that the sustainable level of aquifer withdrawal is approximately 10,000 acre-feet per year (AFY). The city’s total demand — including municipal, industrial, remedial and irrigation needs — was 11,600 AFY, with a projected demand of 12,000 AFY by 2040. Additional reviews put current use at 12,500 AFY, with demand during dry years at 15,000 AFY.
Without a significant reduction in the amount of groundwater pumped in the area, water levels in the wellfield would continue to decline.
In response, BPU worked with our team to initiate three programs that align closely with the Equus Beds‐Walnut Regional Advisory Committee priority goals. The programs:
Wastewater reuse and recycling.
The City of McPherson provides a significant percentage of its treated wastewater effluent to CHS refinery for additional treatment and subsequent reuse to support cooling and process requirements within the refinery. The result is decreased demand and stress on CHS Refinery and BPU water resources, providing value to all aquifer users.
Treatment and utilization of impaired water resources.
McPherson BPU treats and utilizes groundwater impacted by volatile organic compounds (VOCs) as part of the public water supply (PWS) system. This combines groundwater remediation and beneficial reuse of the treated groundwater to minimize the impact on the local aquifer.
BPU also constructed a water blending facility to manage nitrate impacted water resources within the local wellfield area. This initiative allows for continued use of the local groundwater resources that would be unusable for PWS if not effectively managed.
Acquisition of available irrigation water rights.
BPU has acquired water rights in the McPherson Intensive Groundwater Use Control Area (IGUCA) and placed them in the Water Rights Conservation Program (WCRP), reducing aquifer stress and preserving water for future use.
Going further.
To obtain additional water supply, BPU evaluated opportunities to acquire property about 20 miles south of McPherson, in a highly rechargeable area of the aquifer. After evaluating the area for groundwater conditions and determining chloride contamination would not be drawn into the area from a historic oilfield brine disposal area, BPU is developing the McPherson South Wellfield (SWF) project, which will include three new public water supply wells, well houses, raw water collection piping, power supply and access roads.
A new 20-inch water transmission line to the existing water blending facility will be constructed. A new water treatment facility will address iron and manganese removal with greensand filtration. It will also accommodate the potential for future advanced water treatment, allowing its supply to be blended with current groundwater supplies and introduced into the distribution system through the existing high service pump station. Our team also developed reports and designs for all phases (wells, wellhouses, pipeline and water treatment plant).
The development of the SWF will reduce stress on the existing wellfield and allow for operation of groundwater wells within sustainable levels to benefit all water users within the McPherson IGUCA. Future consideration may be given to remedial or water supply management strategies focused on reduction of chloride contamination in the vicinity of the SWF.