North Hills Project (Helena)
High-density subdivisions in the North Hills and declining groundwater levels have caused concern about how much development can occur, how densely homes can be spaced, and if restrictions on water usage are needed. Elevated nitrate levels have been seen in some wells, creating concerns about the use of individual septic systems in places where thin soils overlie shallow fractured bedrock. These concerns resulted in the designation of a Temporary Controlled Groundwater Area (CGWA) by the Montana Department of Natural Resources and Conservation (DNRC) in 2002 and again in 2008.
- An improved understanding of the geologic setting, aquifer properties, aquifer recharge, and aquifer discharge have been obtained through the collection of detailed hydrogeologic data.
- Monitoring of water levels has allowed the potentiometric surface to be better defined. Aquifer tests and water chemistry have been used to define aquifer properties and the degree to which aquifers are connected, and to evaluate water-quality patterns.
- Numerical models of groundwater flow have been developed using these data. These models can be used to evaluate the impacts of various development scenarios.
Project Fact Sheet — Aug 2011 (pdf file)
- Slide shows presented at a Public Meeting, October 12, 2011 at UM Helena:
North Hills Hydrogeology(pdf file )
North Hills Groundwater Modeling (pdf file)
- Slide show presented at the 2014 Nitrate in Montana Hydorlogic Systems Conference, April. 23, 2014:
Sources of Nitrate in Groundwater in the North Hills and Scratchgravel Hills (pdf file)
Project Data avaliable here:
Project Duration: July 2009 to June 2011
GWIP Personnel Assigned:
Jane Madison – Professional Scientist
James Swierc, Lewis and Clark County Water Quality Protection District, Helena, MT
Allison Brown – Student Assistant