Estimation of water environmental capacity and pollution load reduction for urban lakeside of Lake Taihu, eastern China

[Display omitted] Chinese urban lakeside with dense water networks are experiencing the increasingly intensified social–economic activities and serious surface water pollution. The estimation of water environmental capacity and pollution load reduction are crucial supports for restoring lakeshore aquatic ecosystems. In this study, a feasible environmental model and some model parameter identification methods were used to calculate the water environmental capacity and pollution load reduction for a typical urban lakeside, namely, Lake Taihu. The results indicated that the regional annual environmental capacities for TN, TP, CODMn, BOD5, and NH3-N were 99.25, 7.77, 37.36, 144.63, and 95.85 t under reduced 20% objective, respectively and −37.31, 9.28, 185.81, 27.14, and 148.80 t under Class III objective, correspondingly. The TN, TP, CODMn, BOD5, and NH3-N pollution loads are required to be reduced by 60%, 56%, 77%, 62%, and 51% for satisfying the reduced 20% water quality objective, respectively, and 115%, 47%, −16%, 93%, and 24% for achieving Class III objective, respectively. Among the rivers, the Liangxi, Maligang, and Lucun Rivers had large environmental capacities and pollution load reductions under both objectives, constituting more than half of the total regional values. The TN, TP, BOD5, and CODMn environmental capacity and pollution load reduction were significantly higher during the rainy period than during the other periods.