Laserfiche WebLink
Alluvial water monitoring of Apache Canyon began in May of 1984 with the <br /> installation of a well near the mouth of the canyon (Figure 1). Monthly water level <br /> measurements exhibit fluctuations with the availability of water from the surface <br /> (Appendix 2). Generally, water levels increase during the wetter months of June, July and <br /> August and decrease during the fall and winter months. Pump tests conducted indicate <br /> low yield with the well being pumped dry in a very short time. The well inventory <br /> conducted by WFC in 1984 indicated no water wells or water usage within Apache Canyon. <br /> During August 1985, a series of 19 alluvial holes were drilled down to the bedrock <br /> layer in the canyon to further identify the alluvial characteristics. Mapping of the valley <br /> bottom deposits was conducted in September 1985 and presented on Figure 2 in plan view <br /> and Figure 3 in profile. As indicated, bedrock ranges from 12 to 17 feet below the surface <br /> with upper material consisting of topsoil and colluvial deposits. Horizontal extent of the <br /> material is limited to the valley bottom which is generally 100 to 300 feet wide and <br /> generally corresponds with the tree line of the slopes. Topsoil ranges in thickness from 12 <br /> to 70 inches and is generally a loam to silty clay loam. Colluvial underlying materials are <br /> subangular to angular sands, gravels and shales. <br /> In June, 1985, WFC excavated four (4) backhoe pits in Apache Canyon to determine <br /> the presence or absence of subirrigation. Pit locations are shown on Figure 1. Pit <br /> descriptions are given in Appendix 3. Presence of an moisture regime or reducing <br /> zone was the criteria used to evaluate subirrigation. Evidence of a reducing zone less <br /> than or equal to 6 feet from the surface would indicate subirrigation; unless soil color and <br /> mottling in the rooting zone indicated vegetation was not relying on or enhancing <br /> vegetation. The investigation revealed a reducing environment is not present within 6 <br /> feet of the surface and as such, subirrigation is not a phenomenon in Apache Canyon. <br /> With the above description of the valley bottom, an Alluvial Valley Floor (AVF) <br /> determination was made. As per the CMLRD definitions, "Alluvial Valley Floor means the <br /> unconsolidated stream-laid deposits holding streams with water availability sufficient for <br /> subirrigation or flood irrigation agricultural activities but does not include areas upland <br /> which are generally overlain by a thin veneer of colluvial deposits composed chiefly of <br /> debris from sheet erosion, deposits formed by unconcentrated runoff or slope wash, <br /> together with talus, other mass movement acumulations, and windblown deposits". Data <br /> -5- <br />