GWIP at the Legislature

 
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The Ground Water Investigation Program (GWIP), established by the 61st Montana Legislature through House Bill 52, was prepared by the 2007/2008 Water Policy Interim Committee (WPIC). WPIC recognized that competition for water resources and the lack of detailed information on groundwater/surface-water interaction has challenged water-resource management and development in Montana.

2010-2011 Biennium
Investigations and Concerns:
(Click the project name to view the poster)

1) North Hills area, Helena — Subdivisions in this area raise the concerns of impacts to water-rights holders by declining water levels, and possible impacts from use of individual septic systems.

2-3) Four Corners and Belgrade area, lower west Gallatin — The possible hydrologic effects of land-use conversion from irrigated agriculture to high-density residential have raised questions concerning both water quality and water availability and groundwater/surface-water interaction. Shallow groundwater in connection with the surface-water systems may be impacted by withdrawals and waste water due to continuing growth pressures.

4) Lower Beaverhead River West, Dillon — The increased number of high-volume production wells since the mid-1990s has caused concerns for senior water-rights holders and raised the issue of possible stream depletion by induced flow away from the stream or capture of stream recharge. Final Report Nov–2012

5) Scratchgravel Hills, Helena — Increased subdivisions and declining water levels have been observed in some parts of this project area, indicating a need to better quantify aquifer recharge and withdrawals.

6) Florence, Bitterroot Valley — Increasing population density in the Bitterroot Valley has increased the demand on the aquifer and the possibility of induced contamination of drinking water by septic waste drainage.

7) Flathead Valley Deep Confined Aquifer — The increase in high-capacity municipal, irrigation, and domestic wells and localized water level declines in the deep aquifer have raised concerns about the long-term sustainability of this water supply.

nominated GWIP sites
WPIC found that: "Continued and expanded study of ground-water resources is vital to shaping statewide policy as well as providing
the data necessary for local decisions regarding water."

Program Status

Forty projects have been nominated for inclusion in the GWIP work plan. For the 2010-2011 biennium, projects are underway in the seven highest priority sites. Each investigation is expected to take from 1 to 3 years tocomplete. The Steering Committee is currently prioritizing the 2012–2013 biennium projects. Each biennium, the Ground-Water Assessment Steering Committee prioritizes the list of projects based on the following criteria:

  • Subdivision growth rate (Score 1-5)
  • New Wells (Score 1-5)
  • Designated Closed Basin (Score 0=no, 5=yes)
  • Flood to Sprinkler conversion (Score 1-5)
  • Impaired Water Quality (Score 0=no, 5=yes)
  • Expansion of Industrial water use (Score 0 or 5)
  • Expansion of Agricultural water use (Score 0 or 5 )
  • Population density (Score 1-5)
  • Water Class or usability (Score 1-5)
  • Information already known (Score 1-3)
  • System Complexity (Score 1-3)
  • Highly valued Ecological water system (Score 0=no, 5=yes)
  • Basin fill or bedrock Aquifer Systems (Score 1-3)
  • Diversity of hydrogeology and issues (Score 1-3)
  • Controlled groundwater Area (Score 0=no, 5=yes)
  • Availability of Match Funds committed 2010 (Score 0=no, 5=yes)
  • Match Funds have been requested (Score 0=no, 2=yes):
    • Maximum possible score = 74
Instrumenting Blacktail Creek, Dillon to measure stream flows

Program Products:

The final products for each sub-basin investigation are expected to include:

  • A detailed report that describes the hydrogeologic system,
  • A computer model that simulates hydrogeologic features and
    processes, and
  • A comprehensive set of hydrogeologic data available online
    through the Ground-Water Information Center (GWIC).

Computer models will be used to simulate
the hydrogeology and predict the effects of
land-use changes on groundwater and sur-
face water such as this preliminary model
of the Scratchgravel Hills.

 

The models, reports, and supporting data will be technical in nature and used directly by scientists and engineers representing agencies, land owners, senior water-rights holders, new applicants, and other stakeholders.changes in land use and population in the Bitterroot

Changes in land use and population
growth create dramatic numbers of
wells in some areas. Here, wells in
just one area of the Bitterroot Valley
are shown.

 

 

 

 


 

Installing a water-level transducer near Kalispell
 
 
Drilling near stream ob- servation wells in Gallatin County
 
Running an aquifer test near Helena
running aquifer test near Helena, Montana