Assessment of glacier water resources based on the Glacier Inventory of China KANG Ersi, LIU Chaohai, XIE Zichu, LI Xin, SHEN Yongping Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China E-mail: eskang@lzb.ac.cn ABSTRACT. According to the division into subareas of water-resource distribution in China, and based on the Glacier Inventory of China (GIC), China’s total glacier water storage is 5040.2  10 9 m 3 , 33.0% of which is distributed in the southwest drainage basins and 64.1% in the northwest inland drainage basins, forming enormous solid reservoirs with plentiful freshwater storage. Glacier change in China is estimated for the periods from the Little Ice Age (LIA) maximum to about 1960 and from 1960 to 1995. The relative glacierized area loss is 23% and 8.9% respectively for maritime glaciers and 15% and 4.9% respectively for continental glaciers. The normal annual glacier meltwater runoff is estimated at 60 465  10 6 m 3 by the climate parameter temperature-index method, 38.7% of which is distributed in the northwest inland drainage basins, and at 61 574  10 6 m 3 by the glacier system temperature-index method, 41.5% of which is distributed in the northwest inland drainage basins. Simulation of glacier meltwater runoff under the temperature change ratio of 0.03 K a –1 by the glacier system model in west China between 1980 and 2000 indicates that the total glacier meltwater runoff increment is 10.8% overall, 14.3% in the inland drainage basins of northwest China and 9.0% in the outflow drainage basins of southwest China. 1. INTRODUCTION Glaciers are not only active in energy and mass exchange with the atmosphere, but are also important water resources that contribute meltwater to river discharge. Glaciers participate in the global water cycle and, with their solid water storage, are an important component of the water balance. As solid reservoirs, glaciers continue to receive the mass nourishment of solid precipitation from the atmos- phere, and their meltwater feeds and regulates river discharge. Their solid water storage can become usable water resources only when it is melted and generates meltwater runoff (Kang and others, 2008). According to the published 12 volumes of the Glacier Inventory of China (GIC) consisting of 22 parts in 21 books, there are 46 377 glaciers covering an area of 59 425 km 2 , with ice storage of 5600 km 3 , in western China (Shi and others, 2008). Total glacier meltwater runoff in China is estimated at 60.465  10 9 m 3 a –1 (Yang, 1991). Thus, in the integrated assessment of water resources in China, the assessment of glacier water resources is very important. To support the rational allocation and management of water resources, an assessment of China’s glacier water resources must be made for the water-resource subareas. First, the glaciers and their water-resource status must be summed up in different orders in west China, the assessment including the distribution, types, characteristics and water- balance status of the glaciers, and their role in the mountain runoff of glacial meltwater. Secondly, a trend analysis of glacier change must be carried out to show historical variations, and the future trend of glaciers and their meltwater runoff predicted under various climate-change scenarios, especially for the inland river basins where the glacial meltwater constitutes a large proportion of the mountain runoff. Thirdly, scientific understanding of inter- actions among glaciers, climate change and water resources must be improved. The basis for assessing glacier water resources is the completion of the GIC (Shi and others, 2008). Statistical analyses are performed on the glacier inventory data to show the characteristics of glacier distribution. In addition, the results of the long-term glacier monitoring at Tien Shan Glaciological Station are analyzed, and data from field expeditions and investigations on representative glaciers are used. Then the China Glacier Information System (Wu and Li, 2004) is applied and some simulation methods are used. Based on the above, we have made a preliminary assess- ment of China’s glacier water resources. This paper presents the main results of the assessment based on the GIC, and discusses the distribution of glaciers in the water-resource subareas, glacier change, normal glacier runoff and changes in glacier runoff. 2. DISTRIBUTION OF GLACIERS IN THE WATER- RESOURCE SUBAREAS According to the manual of the World Glacier Inventory, China’s mountain glaciers are distributed in the drainage basins which are classified into five orders and ten first-order drainage basins (Shi and others, 2008). According to the Chinese Hydraulic Engineering Society (2002), glaciers in west China are distributed in four first-order water-resource subareas: the Northwestern Rivers region, the Southwestern Rivers region, the YellowRiver region and the Yangtze River region (Fig. 1). The statistics of glacier distribution in the water-resource subareas are based on the GIC data. The results are shown in Figure 2. Figure 2 shows that the glaciers are mainly located in the Northwestern Rivers region, which is an arid area consisting of various inland river basins (Liu and others, 1999), with most of the others located in the Southwestern Rivers region, which is a humid area with rivers draining to the ocean. The glaciers in the arid inland area are of continental type, while Annals of Glaciology 50(53) 2009 104 Downloaded from https://www.cambridge.org/core. 10 Dec 2021 at 18:58:36, subject to the Cambridge Core terms of use.