Uttormark, Paul D.Hutchins, Mark L.2005-09-012005-09-011978-04http://udspace.udel.edu/handle/19716/1545Over the past several years input/output models have been used increasingly as decision-making aids in the design of lake restoration activities because they provide an approximation of the link between nutrients influx and lake trophic status. To evaluate the applicability of these models as design tools, a study was conducted in which "before" and "after" data were obtained for twenty-five lakes which experienced reductions in nutrient inflow, and comparisons were made of measured and predicted changes in lake conditions. Four input/output models were used as predictive tools to describe lake response: those reported by Dillon and Wigler (1974) and Vollenweider (1975, 1976) and a model developed in this study in which cellular biomass, rather than total phosphorus, is used as the trophic state indicator. Comparisons of measured and predicted responses were based on general descriptions of trophic status; Secchi depth, including the Trophic State Index (TSI) reported by Carlson (1977); and a Lake Condition Index(LCI) reported by Uttormark and Wall (1975).3366644 bytesapplication/pdfen-USInput/Output modesLake Restorationdecision criteriaTechnical Report