The Potential for Water Yield Augmentation From Forest Management in the Rocky Mountain Region1

Abstract

ABSTRAn:With the exception of the Sierra-Cascade mountain ranges, the Rocky Mountain chain is the only portion of the western United States that consistently yields more than 3 cm of flow annually.Ten to 15 percent of the land mass in the redon produces the majority of the total flow. This paper addresses the opportunities for increasing flow through forest manipulation, and summarizes the research base that has yielded the current "state of the art" understanding of how snow pack and vegetation management can influence water yield. The optimal harvest design appears to consist of small openings. irregularly shaped, and about 3 to 8 tree heights in width parallel to the wind. (KEY TERMS: watershed manage;ent; water yield; water yield augmentation; snow pack management; vegetation manipulation; hydrology.) 'Paper No. 83077 of the Wuter Resources Bulletin. 'Principal Hydrologist, Rocky Mountain Forest and Range Experiment Station, USDA Forest Service, 240 W. Prospect St.. Fort Collins, Colorado 359 WATER RESOURCES BULLETIN 80526.

Climate change, forests, fire, water, and fish: Building resilient landscapes, streams, and managers

“…The actual performance of thinning in increasing water yields, however, is not well established (e.g., Troendle and King 1987;Troendle and others 2010). In high elevation forest environments, increases in snowpack due to reduced canopy have been documented (Wilm 1944;Wilm and Dunford 1948;Troendle 1983). However, success has not been unequivocally determined for thinning (e.g., Wilm and Dunford 1948;Troendle and King 1987;Ffolliott and others 1989), because it is thought that the residual stand can develop rapidly to utilize the available water.…”

“…There are, however, questions about whether water yield increases realized in small experimental basins (typically less than 10 km 2 ) translate into increases from large basins on the order of a few thousand km 2 (Troendle 1983;Troendle and others 2010). There are also questions about whether the larger fires that have been occurring in recent decades will translate to greater risks of flooding in large basins post-fire.…”

Wildland fire in ecosystems: effects of fire on soils and water

“…More snow accumulates and is retained longer into the winter season on "cooler" than on "warmer" sites because of lower solar radiation levels impinging on the former sites. More snow also accumulates in sparsely stocked forests than in more dense forests, and additional snowfall is deposited in small openings in a forest canopy because of increased turbulence (Troendle 1983, Ffolliott and others 1989, Brooks and others 2003 or through the reduction in the amount of snow intercepted by the forest canopy (Troendle and Meiman 1984, Satterlund and Adams 1992, Brooks and others 2003. Once snowmelt is initiated in the spring, the rate of melt becomes more rapid in the forest openings than under dense vegetative canopies because of greater levels of solar radiation impinging on the open site.…”

Water and nitrogen processes along a typical water flowpath and streamwater exports from a forested catchment and changes after clear-cutting: a modelling study

“…Hydrological changes caused by clear-cutting include increased accumulation of snow, earlier onset of snowmelt and higher snowmelt intensity and elevated groundwater table levels (Päivänen, 1982;Troendle, 1983;Whitaker et al, 2002) and increased runoff (Stednick, 1996). During the growing season both interception and transpiration decrease due to the removal of the tree stand (Calder, 1990;Buttle et al, 2000;Whitaker et al, 2002).…”