The complete WRENSS hydrologic model

TitleThe complete WRENSS hydrologic model
Publication TypeConference Proceedings
Year of Conference2004
AuthorsSwanson, R. H.
Conference Name72nd Annual Western Snow Conference
Series TitleProceedings of the 72nd Annual Western Snow Conference
Date PublishedApril 2004
PublisherWestern Snow Conference
Conference LocationRichmond, B.C.
KeywordsWRENSS, WRNSHYD, WinWrnsHyd, snow accumulation, forest management, peak flow changes

In 1980, the USEPA published a set of graphical procedures to estimate the hydrologic effects of various forest silvicultural practices on water yield and quality. The results from the hydrologic procedures (which I abbreviate as Wrns to distinguish the hydrologic procedure from the entire WRENSS handbook) were the basis for most of the subsequent analyses. Most of the parameters needed to operate Wrns were available from sets of regionalized curves for all forested regions in the United States. Forestry Canada produced an MSDOS version, WRNSHYD, for the hydrologic procedures, with the regionalized curves extended into Canada based on climate and forest similarities, WRNSHYD has received wide use in both Canada and the United States. A new program developed jointly with the US Forest Service, WinWrnsHyd, that overcomes most of these drawbacks is now available. It incorporates the latest research on snow accumulation from the USDA Rocky Mountain Research Station. It is programmed in Microsoft Access and uses database tables as input so that harvesting scenarios can be created with a GIS or other forest planning tool. Silvicultural input data can consist of a series of “snapshots” of forested land units at various times and the subsequent impact on water yield simulated as a batch calculation.