Water Environmental Capacity Calculation Based on Control of Contamination Zone for Water Environment Functional Zones in Jiangsu Section of Yangtze River, China

Abstract

In recent years, due to unsustainable production methods and the demands of daily life, the water quality of the Yangtze River has deteriorated. In response to Yangtze River protection policy, and to protect and restore the ecological environment of the river, a two-dimensional model of the Jiangsu section was established to study the water environmental capacity (WEC) of 90 water environment functional zones. The WEC of the river in each city was calculated based on the results of the water environment functional zones. The results indicated that the total WECs of the study area for chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP) were 251,198 t/year, 24,751 t/year, and 3251 t/year, respectively. Among the eight cities studied, Nanjing accounted for the largest proportion (25%) of pollutants discharged into the Yangtze River; Suzhou (11%) and Zhenjiang (12%) followed, and Wuxi contributed the least (0.4%). The results may help the government to control the discharge of pollutants by enterprises and sewage treatment plants, which would improve the water environment and effectively maintain the water ecological function. This research on the WEC of the Yangtze River may serve as a basis for pollution control and water quality management, and exemplifies WEC calculations of the world’s largest rivers.

Applying water environment capacity to assess the non-point source pollution risks in watersheds

“…Previous studies showed that the simulation results were acceptable when 𝑅 >0.6, 𝑁𝑆𝐸>0.50 and 𝑀𝐴𝑃𝐸 values between 0 and 1 (Gassman et al 2007, Moriasi et al 2015. Furthermore, the results were satisfactory if the 𝑃𝐵𝐼𝐴𝑆 of runoff and pollutants were within ±25% and ±70%, respectively (Ma et al 2021). With the 𝑁𝑆𝐸 coefficient >0.50, 𝑅 >0.70 as well as 𝑃𝐵𝐼𝐴𝑆 and 𝑀𝐴𝑃𝐸 values between reasonable ranges, the Le 'an River Watershed model calibration results were considered satisfactory.…”

Research on water environmental capacity accounting of the Yongzhou Section of Xiangjiang River Basin based on the SWAT-EFDC coupling model

“…However, using the average flow rate of the driest month for the past 10 years is too strict for the Xiangjiang River Basin where the water quality is still excellent. Based on the actual situation, 90% of the average flow rate of the driest month is selected as the design flow to calculate the conservative water environment capacity (Ma et al 2021). On the other hand, the pollutant source survey data of this project uses 2017 as the base year.…”

A Risk Management Method for the Whole Route of Ferry Vehicles Based on Machine Recognition

“…In recent years, the national and industry competent departments have issued a number of policy documents, requiring further strengthening the control capacity of passenger ships, especially the Yangtze River passenger ships. In 2020, the Safety Committee of the State Council issued the Three Year Action Plan for the Special Rectification of National Work Safety, which pointed out that the safety supervision of "four types of key ships" and "six zones and one line" key waters should be strengthened, and ferries should be severely cracked down on adventurous voyages that exceed routes, passenger quotas, approved load lines, and approved wind resistance levels [1]. In response to the national policy requirements, Jiangsu Province took solving the Yangtze River crossing safety problem as a breakthrough to comprehensively improve the channel safety production management service capacity.…”