Engineering Report for Effluent Disposal in Dayton Sewer Service Area Raises Concerns About Capacity

News Release                 

October 25, 2024                                       

Lyon County Must Pause Issuance of Will-Serves, Final Maps and Building Permits in Dayton Due to Design Flaws in Aspen Creek Rapid Infiltration Basins (RIBs)

Dayton, Nevada – Lyon County Utilities has received a comprehensive engineering report from AtkinsRealis, revealing significant design flaws in the Aspen Creek Rapid Infiltration Basins (RIBs), which have hindered the system’s ability to meet its designed effluent disposal capacity. As a result, effective immediately, Lyon County does not have the effluent disposal capacity to support additional growth within the Dayton Sewer Service Area and, therefore, cannot issue new will-serve letters, final maps, or building permits for developments in Dayton that will contribute additional sewer flows until a solution is identified and implemented.

If a developer desires to do so, Lyon County will continue to process new applications for Final Maps and Improvement Permits to keep projects moving through the process until the above-described issues are resolved. This action does not affect existing residents or developments with already issued building permits.

The Aspen Creek RIBs were originally designed by DOWL to dispose of 1.4 million gallons of treated effluent per day (MGD) to support Dayton’s growing community. Construction began in October 2022, with the project reaching substantial completion by July 2023. However, in October 2023, standing water (ponding) and rising groundwater (mounding) were observed in the basins—indications that the RIBs were not functioning as designed.

In response, Lyon County launched an investigation, first enlisting DOWL, and later signing a contract with AtkinsRealis in May 2024 to perform a thorough review of the RIBs’ design and operations. The final report, submitted by AtkinsRealis on October 19, 2024, confirmed that the RIBs’ actual disposal capacity is only 25% of the designed amount, or 350,000 gallons per day.

Lyon County is actively working to resolve the issue, including the scheduling of discussions with the Nevada Division of Environmental Protection (NDEP) and AtkinsRealis to evaluate both short- and long-term solutions that will mitigate the practical effect of this unexpected reduction in capacity and minimize impacts on continued development in Dayton. The County is also engaging with the development community to find potential solutions for effluent disposal.

For further information, please contact Lyon County Utilities at (775) 246-6220.