丹江口水库水体营养状态空间特征分析

Spatial Characteristics of Nutrient Status in Danjiangkou Reservoir

该研究关注丹江口水库的水环境与水生态安全问题,针对库区表层水体营养状态开展了采样分析与空间特征评估。通过在整个库区内布设66个加密监测点位,测定了总氮、总磷、高锰酸盐指数、叶绿素a浓度、透明度等5项水质指标,并核算了水体综合营养状态指数。基于地理信息系统,综合使用插值与聚类等空间分析技术,进一步评估了水体营养状态空间特征,并针对各特征区域开展了敏感因子识别与问题成因分析。结果表明,丹江口水库水体整体处于中营养水平,且存在显著空间差异。上游汉江和丹江干流来水,以及环库支流面源对局部水域表层水体水质影响显著,但水库表现出较强的自净能力,"南水北调"核心水源区处于贫营养水平。未来应面向不同区域开展针对性防控措施,减少入库氮磷污染物通量。

The issue of the water environment and water ecological safety of Danjiangkou Reservoir were concerned in this study.A series of sampling analysis and spatial estimations were carried out on the nutritional status of surface water.66 monitoring points were set in the whole reservoir area and five water quality indicators were measured,including total nitrogen,total phosphorus,CODMn,chlorophyll a concentration,and transparency,based on which the comprehensive nutrition status index(TLI)was calculated.The geographic information system was employed and a series of spatial analysis techniques such as interpolation and clustering are used to further evaluate the spatial characteristics of the nutritional status of water bodies,and to carry out sensitive factor identification and problem cause analysis for each characteristic area.The results show that the overall water body of the Reservoir is at a medium nutrient level with significant spatial differences.The main flows of Hanjiang and Danjiang and the small tributaries around reservoirs,as well as non-point sources have significant impacts on local surface water quality.However,with the great self-purification ability of the Reservoir,the core water source area of the South-to-North Water Diversion Project is at a poor nutrition level.In the future,different targeted control measures should be taken in different regions to reduce the flux of nitrogen and phosphorus discharges to the Reservoir.