Aspen Bibliography

Predicted increased water yield after clearcutting verified in west-central Alberta

Document Type

Report

Source

Canadian Forest Service, Northern Forestry Center

First Page

1

Last Page

46

Publication Date

10-1977

Abstract

The effects of clear-cutting on the North Western Pulp and Power Company Ltd. lease near Hinton, Alberta on water yield were predicted to be (1) an increase in streamflow during the snowmelt freshet, (2) an annual yield increase of 20-30% , (3) an increase in storm flow peak magnitude of four to five times, and (4) a longevity of more than 30 years before these effects begin to diminish . These predictions were made using an informal model that states that the change in water yield resulting from forest harvest may be inferred from the alterations in stand structure, density, and arrangement that occur during harvesting which produce predictable changes in the interception, transpiration, snow accumulation, and snowmelt processes that in turn affect generated runoff . Validity of the predictions was tested by statistically comparing water yield from nine logged and nine unlogged catchments on the lease. Results were (1) 59% more streamflow during the snowmelt freshet, (2) 27% greater yield over the gauged season (April 25-September 15), and (3) an increase in storm peaks of 1-1/2 to two times. Since the first two effects confirmed the predictions, and the average harvest age is 10 years, longevity will likely be as predicted also.

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