中国主要入海河流河口集水区划分与分类

Preliminary delineation and classification of estuarine drainage areas for major coastal rivers in China

采用GIS技术开展中国主要入海河流的流域边界及其汇水单元、河口集水区的划分及其分类。基于ArcGIS水文分析模块划分出15条入海河流的汇水单元,并通过5种不同汇水单元面积等级的划分来表达各入海河流汇水单元的详细程度;划分的流域面积与相关文献资料对比偏差在10%以内;在流域与汇水单元划分的基础上,基于感潮河段的数据收集,确定出88个中国主要入海河流的河口集水区。通过建立分类指标体系,采用聚类分析方法,划分出5类河口:第一类EDA主要分布在环渤海地区、山东半岛和广东沿海;第二类EDA主要分布在长江口和杭州湾周围;第三类EDA主要分布在江苏北部沿海和辽东半岛;第四类包括山东江苏交界处沿海、江苏南部沿海;第五类主要分布在福建浙江沿海、珠江口、长江口、海河口附近、辽河河口附近,并利用快速生物评价法验证河口分类的合理性。研究成果可为进一步开展我国近海河口和海域营养盐基准制订与生态分区提供基础空间数据与方法借鉴。

Classification of estuarine and coastal waters has been recognized as a critical step for natural resource managers to describe and inventory coastal systems, understand constraints, predict the most sensitive systems, manage and protect coastal resources. However, the research on ecological classification in China is still in infancy, especially the classification of estuarine and coastal waters at regional or nationwide scale. This research employed Geographical Information System （GIS） and multivariate statistical analyses to delineate and classify the watersheds and estuarine drainage areas from fifteen major coastal rivers in China. The Hydrology module in ArcGIS environment was used to delineate the sub-watersheds from the fifteen coastal rivers, represented by spatially different details with five thresholds. The watershed boundaries of fifteen coastal rivers were further delimited and validated with literature documents. The deviation was less than 10%. Based on the analysis of spatial distribution of tide heads for fifteen rivers and the previously delineated sub-watersheds, 88 estuarine drainage areas （EDAs） were further defined. A five-class classification system was developed with the hierarchical cluster analysis, based on the physical, biological and chemical properties of EDA. Estuaries having the smallest total EDA were grouped as class one, and they are located in Bohai Bay, Shandong peninsula and coastal areas of Guangdong; estuaries having the lowest average salinity range and the highest concentration of total suspended solid were grouped as class two, and they are located in Yangtze River estuary and Hangzhou bay; estuaries having the highest average depth and the highest wind speed were grouped as class three, and they are located in coastal areas of Northern Jiangsu and Liaodong peninsula; estuaries having the lowest dissolved oxygen and highest tidal range were grouped as class four, and they are located in coastal areas between Shandong and Jiangsu, coastal areas of Southern Jiangsu; estuaries having the largest average EDA and highest freshwater flow were grouped as class five, and they are located in coastal areas of Fujian and Zhejiang, Pearl river estuary, Haihe River estuary, and Liaohe River estuary. A rapid bio-assessment procedure was successfully employed to validate the classified result based on the collected data from literatures. The findings in this study provided the basic geospatial data for further developing nutrient criteria and eco-regionalization in estuarine and coastal waters in China.