深圳湾流域面源与截排溢流污染特征及其对水环境的影响

随着点源污染逐步得到有效控制,面源与截排溢流污染对水环境的胁迫日益突出。基于土地遥感数据、城市排水管网等资料,构建流域—海湾一体化水环境模型,探讨深圳湾流域面源与截排溢流污染特征及其对水环境的影响,研究表明：（1）雨季COD、NH₃-N和TP单位面积面源与截排溢流污染负荷分别为17.21 t/km²与10.21 t/km²、0.17 t/km²与0.69 t/km²、0.04 t/km²与0.07 t/km²;（2）面源与截排溢流污染时间上主要集中于大雨及以上等级降水较多的5月和8月,空间上主要分布在截排工程集中、下垫面面积较大且坡度较陡的深圳河、大沙河和新洲河流域;（3）面源与截排溢流水体COD、NH₃-N和TP浓度可达地表水V类标准的3.7倍、18.2倍和8.5倍;（4）雨季COD、NH₃-N和TP浓度高于旱季的区域分别超过深圳湾总面积的40%、60%和65%。

Spatio-temporal characteristics of non-point source and sewer overflow pollution and its impacts on water environment in Shenzhen Bay Basin

With the effective control of point source pollution, non-point source and sewer overflow pollution becomes the main type of water pollution. Based on materials of land use, urban drainage network and so on, the basin-bay integrated water environmental model was established, and the spatio-temporal characteristics of non-point source and sewer overflow pollution in Shenzhen Bay Basin as well as its impacts on water environment were analyzed. Results showed that (1) The non-point source and sewer overflow pollution loading per unit area of COD, NH₃-N and TP in rainy season was 17.21 t/km²and 10.21 t/km², 0.17 t/km²and 0.69 t/km², 0.04 t/km² and 0.07 t/km², respectively; (2) The non-point source and sewer overflow pollution was concentrated in May and August with more heavy rainfall observed in Shenzhen River Basin, Dasha River Basin and Xinzhou River Basin with larger area, steeper surface slope and more sewerage cutting projects; (3) The COD, NH₃-N and TP concentrations of non-point source and sewer overflow pollution could approach 3.7, 18.2 and 8.5 times the values of water quality standards, respectively; (4) The areas where the COD, NH₃-N and TP concentrations in rainy season were higher than those in dry season exceeded 40%, 60% and 65% of the total area of Shenzhen Bay, respectively.