Abstract:
This paper is the result of environmental geological survey engineering.
Objectives To meet the water quality monitoring demands arising from rapid urbanization in the Yangtze River Delta, this study takes the Lanlugang River downstream of Dianshan Lake in Qingpu District, Shanghai, as the study area and explores the practical application value of Chinese-made UAV hyperspectral technology in water quality surveys. This research aims to verify the reliability of domestically developed hyperspectral equipment, establish an efficient and low-cost water quality monitoring technical system, and provide scientific support for the integrated ecological and green development of the Yangtze River Delta.
Methods A self-developed hyperspectral imager was mounted on a small UAV platform to conduct low-altitude remote sensing detection over an 8 km reach of the Lanlugang River. Synchronously, water quality parameters were measured at 34 ground sampling sites, yielding data on key indicators including ammonia nitrogen, phosphorus, potassium, and permanganate index. Following a technical workflow of radiometric calibration, reflectance conversion, geometric correction, and feature band extraction, a CARS-LSSVR retrieval model was developed to construct the nonlinear mapping relationships between each indicator and its spectral reflectance.
Results The single-factor water quality classification based on ammonia nitrogen, total phosphorus, and permanganate index shows that Class II water accounts for the largest proportion in the study area, at 99.7429%, whereas Class I and Class III water bodies account for only 0.1518% and 0.1053%, respectively. No Class IV or inferior water bodies were identified, indicating that the water quality in the study area is generally good. This study confirms that the Chinese-made hyperspectral equipment achieves spectral stability comparable with that of international counterparts over the 400–1000 nm range, and that multi-source data fusion can markedly reduce the field workload of conventional water quality monitoring.
Conclusions The results not only provide a replicable technical solution for rapid water quality diagnosis in regions with dense river networks, but also highlight the application potential of Chinese-made remote sensing equipment in the field of water environmental protection, and carry significant practical value for promoting the digital transformation of ecological and environmental governance.
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