Variation of Water Quality and Nutrient Load Limits in Lake Baiyangdian, North China

We used Vollenweider mass balance model that can predict maximum allowable nutrient loading rates or load limits (LM) for prediction of trophic status in Lake Baiyangdian's fresh waters. The average annual hydraulic inflow rate (Q(i)) and nutrient input concentration (C(Pi)) explained most of the variation in LM for guiding the lake management. We found such a single model for total phosphorus (TP) could provide a reasonable fit to trophic status in Lake Baiyangdian. The total phosphorus tolerance input value should not exceed 1.0 x 10(7) g/year, and the tolerance range C(Pi) could be limited in less than 0.108 g/m(3). The research results can facilitate the development of total maximum loads for water diversion from reservoirs and may have broader regional utility. They may also aid the development of nutrient concentration criteria.