River Outfall Survey, Monitoring & Source Tracing

Use remote sensing screening, field verification and detailed technical investigation. First, interpret aerial remote sensing data to flag suspected outfalls and areas. Second, inspect shorelines on foot using a grid-based approach and register wastewater outlets, stormwater outlets and non-outfall features. Third, combine drones, unmanned boats, thermal imaging and other equipment for detailed air, water and land verification. Establish an individual record for each wastewater and urban stormwater outfall and compile a survey report.

Conduct rapid water quality testing for flow, temperature, pH, ammonia nitrogen, total phosphorus, COD and other parameters. Upload photographic records and test data to the survey system for traceability. Set monitoring schedules for seasonal and intermittent outlets, with more frequent sampling after rain, during high flows or flood releases where appropriate. Use CMA-accredited laboratories for verification when needed.

Trace river outfalls whose responsible operators are unclear. Record outfall details, administrative area, wastewater volume, receiving waterbody, control unit, tracing methods and wastewater sources. After three-stage tracing, establish a list of responsible operators and complete records of applicable discharge standards, major pollutants and receiving waters.

Build electronic outfall records, a monitoring database and a unified river outfall map. A survey system and mobile application support timely, traceable field data entry and maintain a consolidated register with an individual record for every outfall.