The Heihe River Basin is the second largest inland river basin in China. In the past 30 years, a relatively complete basin observation system has been established in the Heihe River Basin, which has become an important inland river research base in China. Watersheds are important natural research units, but the boundaries of the Heihe River Basin are not unified. In order to facilitate user use of data, we have collected and organized five common Heihe River Basin boundaries in the literature:

1) From 1985 to 1986, China began to conduct systematic research on the Heihe River Basin as a whole. Based on basic investigations and a large amount of data, early maps of the Heihe River Basin were drawn, with a drainage area of 138900 km ^ 2. The entire watershed is divided into three hydrological balance zones, namely: the balance zone of the Heihe River main flow system, the balance zone of the Beida River main flow system, and the balance zone of the Maying Fengle Mountain front flow system

2) The sub theme of the "Ninth Five Year Plan" national key scientific and technological research project "Research on the rational utilization of water resources in the Heihe River Basin and the coordinated development of economy, society, and ecological environment" considers the integrity of county-level administrative units. Based on the first watershed boundary, the watershed boundary was revised using the administrative boundary at that time, forming the current "Digital Heihe River" information system（ http://heihe.westgis.ac.cn ）The Heihe River Basin boundary announced has a drainage area of 128700 km ^ 2. The division of hydrological units inherits the original idea and is divided into three major water systems, namely the eastern water system, the central water system, and the western water system

3) In the comprehensive management plan of the Heihe River Basin of the Ministry of Water Resources, the area of the Heihe River Basin is determined to be 142900 km2, and the hydrological unit is divided into two independent water systems in the central and western regions and the eastern regions, with areas of 27000 km2 and 116000 km2, respectively

4) In the national water resources comprehensive planning carried out from 2002 to 2006, the working group for the preparation of the "Yellow River Basin (Area) Water Resources Comprehensive Planning" compiled the "Summary Report on the Investigation and Evaluation of Water Resources and Their Development and Utilization in Northwest China" in 2005. A series of physical, geographical, and socio-economic statistical tables and maps were completed based on the secondary and tertiary water resources areas. In this comprehensive planning, the area of the Heihe River Basin is approximately 151700 km2, and the plan does not provide a more detailed sub basin division plan

5) Based on high-precision digital elevation models (SRTM and ASTER GDEM), the boundary of the Heihe River Basin was determined using GIS hydrological analysis methods. This boundary has been verified through remote sensing and field investigations, and modern water resource utilization has also been taken into account in the process of determining the watershed boundary and dividing sub watersheds