Appendix C 

 Happy Valley Hydrology 



on-site and is not delivered to a stream or draw, but there is delivery to the stream in places. No 

 other sources of erosion or deposition were identified through field review. 



Water Yield . , 



Past activities in and around the proposed project area include timber management, agriculture, 

 and home site development. These activities have led to reductions in forest canopy cover, and 

 construction of roads. 



Following field reconnaissance of the proposed project area, it was determined that a detailed 

 water yield analysis would not be necessary for the proposed project area. The stream running 

 through the project area becomes subsurface just below the project area, and areas between the 

 project area and the Wliitefish River have no current or historic stream or draw features that 

 would deliver surface water. As a result, water yield increases from past activities have not been 

 sufficient to create an ephemeral draw or channel beyond the immediate project area; or to 

 deliver surface flow to downstream waters. 



Direct and Indirect Effects 



No Action Alternative 



Direct and indirect effects of the no action alternative would be similar to the conditions 

 described under the existing conditions for water quality and water yield. The water quality and 

 water yield would be unaffected by the no action alternative, and the stream and ephemeral 

 draws in the proposed project area would continue to be affected by natural and pre-existing 

 conditions. 



Action Alternative 



The proposed action alternative would harvest timber from approximately 443 acres. No 

 measurable impacts to water yield are anticipated from the proposed harvesting for the following 

 reasons: 1) The selective nature of the harvest over most of the proposed project area would 

 leave substantial amounts of live trees on the site, and is designed to allow more rapid grovMh of 

 remaining trees, 2) The well-drained nature of the soils would produce little or no detectable 

 change in water yield, 3) The class 3 stream and ephemeral draws within the project area are 

 stable and vegetated with a dense mat of grass and forb vegetation, making them capable of 

 handling potential water yield increases without destabilizing, and 4) A 50 foot Streamside 

 Management Zone on both sides of the discontinous stream would protect the streambank and 

 adjacent vegetation. 



The action alternative would also improve the erosion control and surface drainage on 6.6 miles 

 of existing road, and bring it up to applicable BMP standards for the duration of activity. 

 Portions of the existing road system in the proposed project area would be rehabilitated and 

 made impassible by motorized traffic. Some portions of the existing road and trail system would 

 be left open for seasonal ATV use, and for fire suppression access. Abandoned roads would 

 have erosion control features installed and be left in a condition where future maintenance would 

 not be needed. Portions of trails left passable by ATVs and fire suppression vehicles would have 

 seasonal use restrictions to minimize the potential for erosion and sediment delivery. These 



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