| Abstract: | The geohydrology of the Flathead Indian Reservation was studied to provide information needed to formulate groundwater development plans. Bedrock in the area consists predominantly of slightly metamorphosed carbonate and fine-grained clasitc rocks of the Precambrian Belt Supergroup. Valley-fill deposits consist of alluvium of Holocene age; glacial and glaciolacustrine boulders, cobbles, gravel, sand, silt, and clay of Pleistocene age; and siltstone, fine-grained sandstone, and coal of probable Tertiary age. Most wells in the reservation are completed in valley-fill aquifers--for which well discharge ranges from 0.5 to 1,600 gal/minute and transmissivity ranges from 3.2 to 45,600 sq ft/day. Groundwater flow follows the trend of the respective valleys. Water level in valley-fill aquifers fluctuates seasonally in response to recharge from streams and irrigation canals and discharge from wells. Recharge to valley-fill aquifers occurs by direct infiltration of snowmelt and rainfall, leakage from streams and irrigation canals, subsurface inflow, and irrigation return flow. Discharge from the valley-fill aquifers occurs through evaporation, transpiration by plants, withdrawals from wells, leakage to rivers and streams, and subsurface outflow. Water in bedrock is available from fracture zones of secondary permeability; discharge from wells completed in bedrock ranges from 2.5 to 40 gal/min. Water from wells and springs is calcium bicarbonate or sodium bicarbonate type and contained dissolved-solids concentrations of 42 to 1,100 mg/L. All dissolved constituents in most samples were within Federal drinking water standards. (USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 29761 |
| Citation Author: | Slagle, S. E. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | vi, 152 p. :ill., maps ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 88-4142 |
| Citation Search Results Text: | Geohydrology of the Flathead Indian Reservation, northwestern Montana; 1988; WRI; 88-4142; Slagle, S. E. |
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| Citation Year: | 1988 |
| Type: | citation/reference |
| Text: | Geohydrology of the Flathead Indian Reservation, northwestern Montana; 1988; WRI; 88-4142; Slagle, S. E. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/wri/1988/4142/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/wri/1988/4142/report.pdf |
| URL (PLATE): | http://pubs.usgs.gov/wri/1988/4142/plate-1.pdf |
| URL (PLATE): | http://pubs.usgs.gov/wri/1988/4142/plate-2.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
