FOREST HYDROLOGY ISSUES FOR THE 21ST-CENTURY - A CONSULTANTS VIEWPOINT

Forest hydrology should be a mature science with routine use of hydrol ogical procedures to evaluate the effect of past, current and proposed harvesting practices on water resources. It is not. However, water us ers are pressuring forest managers to exercise their role in managing forested watersheds for water supply. Most forest managers are poorly equipped to carry out this role. Forestry schools need to ensure that their graduates, whether employed in forest management positions or as specialists in watershed management, understand that all forestry ope rations may affect instream or downstream water users. Specialists in forest hydrology should be fully aware of the following: (1) climate a nd watershed characteristics influence streamflow in separate ways; (2 ) forestry practices produce changes in water yield and quality, and t hat only these changes need to be evaluated to estimate their effects; (3) watershed storage is a critical factor in evaluating the effects of harvesting on streamflow; and (4) the effect of harvest on one wate rshed cannot be extrapolated to another without consideration of the p rocesses affected. Research is needed to assist watershed managers in applying models to watersheds for which climate and streamflow data ar e insufficient. Research is also needed to incorporate climate, stream flow and other data for hydrological models into geographic informatio n systems. Joint research projects are needed to develop physical rela tionships between stream channel characteristics of importance to fish eries biologists and streamflow characteristics affected by forest har vest.