Li, H.; Zhang, M.; Yuan, J.; Chen, X., and Yu, G., . Assessment on water environmental capacity of coastal lowlands networked with rivers and lakes in the northern region of Jiaxing, China.
Networked rivers and lakes are widely distributed in coastal lowlands. The water quality in these regions is generally not good and endangers the ecosystem because pollutants accumulate easily. The northern region of Jiaxing, China, was chosen for the case study. This paper investigates the water environmental capacity of coastal lowlands networked with several rivers and lakes. Field measurements were conducted to collect hydrological, water quality, and statistical data in different periods. The study area was divided into river and lake control units, with 10 units in total. The water environment capacity and pollution sources of each control unit were analyzed. The results showed that the pollution load and remnant water environmental capacity of each control unit differ significantly for different periods and control units. The total nitrogen (TN) and total phosphorus (TP) in the region were severely over the standard values. The chemical oxygen demand (COD) and TP in the river control units were higher than those in the lake control units. During the period between October 2018 and June 2019, all control units exceeded the water environmental capacity of TN, but most control units did not exceed the limit for COD. The remnant water environmental capacity of most control units follows the order that the dry period is greater than the normal period, which is greater than the flood period. Finally, according to the pollution sources and water environmental capacity of each control unit, specific measures to improve the water environment were proposed. This study provides references to assess and improve the water environmental capacity in coastal lowlands networked with rivers and lakes.