Project Overview
Nitrate levels in this Wye/O’Keefe Creek/Spring Meadows area of Missoula County have steadily increased over the past 15 years, and have recently exceeded the Maximum Contaminant Level of 10 mg/L, as set by the US Environmental Protection Agency for drinking water and the State of Montana for drinking water.. This project proposes to extend City of Missoula sewer service to the existing Spring Meadows Addition so the 60 homes in the area can connect to City sewer in the future and abandon their existing drainfields. This new sewage collection system is a key step to improving groundwater quality in this area.
Project Area
Spring Meadows Addition is located approximately ten miles northwest of the City of Missoula, northeast of the Interstate 90/Highway 93 interchange. This area is commonly referred to as the “Wye Area”. Spring Meadows Addition falls in Sections 21 and 22 of Township 14 North, Range 20 West at latitude 46° 57’ 43” North and longitude 114° 7’ 13” West. The Spring Meadows Addition and Spring Meadows Drainage are part of the larger O’Keefe Creek drainage, encompassing much of the Wye Area. The topography slopes to the west with approximate elevations of 3200 to 3300 feet.
Project Need
The Missoula Valley Aquifer was designated a “sole source aquifer” by the United States Environmental Protection Agency in 1988, meaning the aquifer is the only source of drinking water for Missoula area residents. The City of Missoula and Missoula County have expressed concern for the protection of the Missoula aquifer and have been engaged in cooperative water quality planning projects since this sole source designation was received. Groundwater quality in the Missoula area has been monitored and studied for many years due to concerns with the effect wastewater effluent from drainfields has on groundwater. The 1994 Cumulative Effects/Carrying Capacity Study and the 1999 Missoula Wastewater Treatment Facility Plan indicate that untreated wastewater from septic systems constitutes a major source of pollution to the Clark Fork and Bitterroot Rivers and poses a threat to the Missoula aquifer.
According to a report prepared by the Missoula Valley Water Quality District, Groundwater Quality in the O’Keefe Creek/Wye Area: 1997/1998, “Residential and commercial development of the O’Keefe Creek/Wye area has led to concerns about potential water quality impacts. Nitrite-N in groundwater is a particular concern due to its association with on-site septic systems, which are used to manage wastewater in the study area due to the absence of municipal sewer service.”
Drinking water quality in the Wye Area/O’Keefe Creek Drainage is currently severely degraded. Water quality sampling over the past 15 years indicates that nitrate levels in many wells have steadily increased. In 2007, the Environmental Protection Agency and Montana Department of Environmental Quality (DEQ) notified Missoula Valley Water Quality District that a water sample from a private well in the area exceeded the Maximum Containment Level of 10 mg/L, as set by the US Environmental Protection Agency for drinking water and the State of Montana for groundwater. Elevated nitrate levels can result in human health effects, including interference with the blood’s ability to deliver oxygen to the body. This may result in a condition known as methemoglobinemia, or blue baby syndrome.
In 2008, Missoula County was notified by DEQ that DEQ could not approve any new drainfields in this area due to the existing water quality violation. In response to the DEQ restriction on new drainfields, the Missoula City County Health Department, in conjunction with the Missoula Valley Water Quality District, conducted a detailed study of the area. This 2008 study, Elevated Nitrates in the Wye/O’Keefe Area, determined that the likely source of contamination for the well in violation of the 10 mg/L was the existing drainfields in the Spring Meadows Drainage. As a result, Missoula County has adopted a “Special Review” for the Spring Meadows Drainage, which essentially prohibits new drainfields. Groundwater nitrate levels in the Wye Area have been a concern for many years. Until the sources of groundwater contamination are removed, the elevated nitrate levels in drinking water wells will continue to pose a significant health threat to area citizens.
Project Formation
In April 2009, Missoula County applied for a preliminary engineering grant from the Treasure State Endowment Program (TSEP) to evaluate alternatives for improving the level of wastewater treatment in the Spring Meadows area in order to improve water quality. A TSEP grant was subsequently awarded and the project study began in the fall of 2009. This study has indicated the most effective and preferred alternative is to extend City of Missoula sewre to the Spring Meadows Addition. In conjunction with the sewer extension, the Missoula City-County Health Department plans to revise their Health Code to require Spring Meadows Addition residents to connect to City sewer at the time of sale of their homes.
Missoula County intends to apply for state and federal grants this year to assist with costs associated with design and construction for this project. If funding is obtained, final design is anticipated for 2011, with construction in 2012.
For more information on the project or to provide comments, please contact Jon Gass, Principal Engineer at WGM Group or Greg Robertson, Public Works Director for Missoula County, as listed below.
WGM Representative
Jon Gass, P.E., LEED AP, Principal Engineer
Email: jgass@wgmgroup.com
Phone: 406.728.4611
General Project Oversight
Missoula County
Greg Robertson, Public Works Director
6089 Training Drive
Missoula, MT 59808
Phone: 406.258.4764
Fax: 406.258.4864
