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Revised April 5, 1985 <br />• tight soils. The relative positions of the water table, capillary <br />fringe and root zone indicates the presence or absence of sub- <br />irrigation at a specific location. Correlation of alluvial ground <br />water conditions in one location with other areas in similar stream <br />valleys can be made by comparing lithology, soils, vegetation and any <br />outside influences such as impoundments or diversions. The quality of <br />alluvial ground water is also central to its suitability for sub- <br />irrigation. <br />Stream Channel Ground Water Hydrology <br />In order to evaluate the possibility of sub-irrigation from ground <br />water in the proposed permit and adjacent area, 6 shallow alluvial <br />wells were installed in the drainage of fish Creek to form a transect <br />crossing the valley, as shown on Map 5, Fish Creek Tipple Hydrology. <br />The wells were installed in backhoe pits to facilitate detailed <br />logging of topsoil, root zone and alluvial materials, and were <br />• constructed with perforated PVC casing to enable water monitoring and <br />sampling. Topsoil and root zone depth, alluvial lithology and water <br />levels from these wells were used in constructing Map 6, Fish Creek <br />Tipple Stream Channel Cross-Sections. Observations were made during <br />the digging of the backhoe pits including depth of soil, depth of root <br />zone, type of alluvial material and water inflow to the pit. Soil <br />mottling or other evidence of periodic ground water fluctuations into <br />the root zone was recorded. <br />With the exception of a few isolated sand and gravel deposits, the <br />upper portion of the channel fill in the intermittent drainages was <br />found to be predominantly tight, sticky clay. The clayey layers in <br />Fish Creek were found to be nearly impermeable, because when digging <br />exposed a gravel layer, the water level in the pit suddenly rose <br />several feet. This would indicate that, while the gravel deposits are <br />satuarated and transmit confined water when excavated, the clay <br />surrounding the gravel severely hinders these deposits from <br />• <br />2.06-16 <br />