Effect of pollution load reduction on water quality in rural lakes in the shallow hill water network area

Abstract

Abstract There is poor water environment quality in rural lakes in the shallow hill water network area north of the Han River on the Chinese Jianghan Plain due to their poor hydrodynamic conditions. We herein selected ten typical rural lakes to simulate water environment improvement. The hydrodynamic and water quality models were built based on MIKE21, while the simulation compared the year-round trends in lake water quality in the current and planning year, and demonstrated the possibility of recharging rural lakes from the backbone of the Han River–Three Inland Rivers networks. The results show that the water quality of the ten lakes has improved significantly after pollution control, with an improvement rate of more than 70%. Pollution interception and management are particularly successful for improving lake water quality in rural lakes. The replenishment of water from the backbone river to the lakes could enhance the fluidity of the rural lakes but cannot eliminate the total phosphorus (TP) risk. Therefore, in the relatively closed water bodies of rural lakes in the shallow hilly water network area, pollution intercept and control is key to controlling TP, and taking measures such as increasing lake hydrodynamic conditions in summer will be a more efficient approach to improve rural lake water quality.