Quantifying pollution contributions across a reticular river network: Insights from water quantity composition analysis

Abstract

Calculating pollution load contribution rate is an effective way to identify pollution sources, which is important in improving water quality management. Reticular river networks pose unique challenges in pollution load contribution rates calculation, as current methods are not applicable to river networks with uncertain flow direction or exhibit low computational efficiency. This study addresses this challenge by offering a new method that transforms the calculation of water quantity constituents in assessment sections into a conserved substance concentration problem. Applied to a typical reticular river network, Suzhou River Network in the Tai Lake Basin, China, total phosphorus pollution load contribution rates demonstrate significant spatial and temporal variations, and are closely associated with factors such as pollution load, rainfall, and water diversion. The developed method stands out for its simplicity and improved computational efficiency, making it particularly suitable for regions with indeterminate flow directions. Quantifying the contribution of pollution sources in reticular river networks to identify sources of pollution helps to improve the precision and pertinence of water pollution management programs.