基于陆基遥感研究降雨过程对人民渠水质影响

利用监测频率为1min的陆基高光谱水质遥感监测仪于2021年9月24日～11月18日在四川德阳人民渠对浊度、悬浮物、总磷等关键水质参数开展连续监测,精细刻画了水质分钟级的动态变化特征,并结合逐时降水数据探究了不同雨强对人民渠水质的影响.结果显示:降雨量与浊度(r=0.82,P<0.001)、悬浮物(r=0.88,P<0.001)和总磷浓度(r=0.81,P<0.001)均存在极显著正相关,而降雨量与总氮浓度(r=0.39,P=0.07)存在正相关但相关性不显著.当小雨时,降雨量少,没有形成明显的地表径流,河流水质几乎不受影响;大雨及暴雨时,地表径流的形成造成浊度、悬浮物和总磷浓度显著增加,总氮浓度增长幅度则较为平缓.通过高频水质数据可以精细刻画从高强度降雨发生到引发流域氮磷污染物大通量、脉冲式输入再到水质短期剧烈变化这一关键流域污染过程,研究结果为高强度降雨频发地区和未来极端降雨增加情景下流域的污染物控制和综合治理措施提供科学依据.

Impact of rainfall process on the water quality of Renmin Canal using ground-based remote sensing

This paper used a ground-based hyperspectral water quality remote sensing instrument with a monitoring frequency of 1minute to continuously monitor key water quality dynamics such as total suspended solid (TSM), turbidity, and total phosphorus (TP) in the Renmin Canal of Deyang in Sichuan Province, from September 24 to November 18, 2021. Continuous monitoring accurately characterized the minute-level dynamics of water quality and explored the impact of different rainfall intensities on the water quality combining with synchronous hourly rainfall data. Through continuous monitoring, the minute-level dynamics of water quality was accurately characterized and the impact of different rainfall intensities were explored on the water quality combining with synchronous hourly rainfall data. Significantly positive linear correlations were found between rainfall amount and TSM (r=0.88,P<0.001), turbidity (r=0.82,P<0.001), TP (r=0.81,P<0.001). However, positive but no significant correlation was found between rainfall amount and total nitrogen (TN) (r=0.39,P=0.07). During light rain, obvious surface runoff was not brought by small rainfall amount, which almost had no impact on the water quality of the river. In contrast, during heavy rain and rainstorm, a significant increase of turbidity, TSM and TP was caused by the formation of surface runoff, while the increase of TN was relatively gentle. Through high-frequency water quality data, the key river basin pollution process could be accurately characterized, from the occurrence of high-intensity rainfall to the large and pulsed input flux of nitrogen and phosphorus pollutants in the basin, and then to the short-term dramatic changes in water quality. Our results provided a scientific basis for pollution control and comprehensive treatment measures in areas with frequent high-intensity rainfall and basins under the scenario of increasing extreme rainfall in the future.