LRES M.S. Thesis Defense: Emery Three Irons
- Monday, May 6, 2019 at 11:00am
- Barnard Hall, 126 - view map
An Investigation of Coliform Contamination in Private Well Water on the Crow Reservation, Montana
The Crow reservation has a rural population that depends on home well water for domestic use. Many of the home wells, constructed at various depths, do not have a suitable well cap, and therefore, are vulnerable to bacterial contamination. Coliform contamination of well water is an important health concern among Crow home well users. Fecal coliform is associated with acute health problems, such as gastrointestinal illness, diarrhea and cramps. This research examines correlations among contaminated wells and a suite of physical characteristics and well protection factors. Physical characteristics include the geologic production formation, land cover and distance to the nearest river. Well protection factors include well cap type and condition, well depth and well age. One hundred water quality samples and well protection factor data were collected at homes along the Little Big Horn River in 2017. Sample analysis was conducted using the Colilert IDEXX Quanti-Tray 2000 method. Spatial data describing the physical characteristics were acquired through a combination of well logs, the National Land Cover Dataset, and the National Hydrography Dataset. The data were analyzed using logistic regression to identify the probability of coliform contamination based on the physical characteristics and the well protection factors. Results demonstrate that logistic regression models were statistically significant (α = 0.05 level) with wells in alluvium having a higher probability of coliform contamination as distance from the nearest river increased. Also, wells with old style caps have a higher probability of coliform contamination. The government of the Crow tribe can decide how to use the results for mitigation efforts and awareness for homeowners with contaminated wells. Also, it is important for the Crow Water Quality Project to archive the results for future planning, development and management.
- Department of Land Resources and Environmental Sciences