【正文】 ? (3) Tradeoffs in water resource allocation among human survival, bioproduction and environmental conservation Shiyang River Watershed: A case of marginal land ? Shiyang River watershed is located in arid area of Western China, with an area of 41,600km2. ? The watershed includes upstream Qilian Mountain Range, Wuwei Oasis in midst, and downstream Minqin Oasis. ? Annual precipitation is more than 200mm in upstream range, from 150mm to 200mm in Wuwei Oasis, and from 100mm to 150mm in Minqin Oasis. ? Most of water resource supply is from precipitation and melted glacier. In downstream Minqin area, water resource supply depends on surface runoff and underground water permeation. Table2 Change in water resource supply in Shiyanghe River watershed Unit: 108m3 1950s 1960s 1970s 1980s 1990s 2022 Runoff 1957 1969 1976 1980 1990 2022 Runoff Source: (1)Yang Yongchun et al, 2022. The human mechanism research of Minqin Oasis change in the lower reaches of the Shiyang River. Geographical research, , : (2) Sun Xuetao, 2022. Analysis on water resource Utilization in Minqin Oasis. China Water Conservancy, Vol. 2022, No. 12: Table 2 indicates water resource supply in Shiyanghe River watershed is relatively steady. The problem is from increasing demand of water resource with rapid population growth and economic development. Table3 Regional distribution of economy and population in Shiyanghe River watershed Units: 104Yuan, person, hm2 GDP Population Urban population Rural population Cultivated land Sowing area Wheat Corn Wuwei 427,607 946,469 272,308 674,161 97,253 116,370 34,590 28,970 Minqin 87,600 302,082 42,332 259,750 64,120 47,720 21,630 6,740 Wuwei / Minqin Source: Gansu Statistics Yearbook 2022 Table3 highlights regional distribution of economy and population in Shiyanghe River watershed. Table4 Demand of water resource in Shiyanghe River watershed in 2022 Unit: 108m3 Whole demand Irrigation Industry Urban living Rural living Forest and grassland Wuwei Minqin Jinchang Total watershed Wuwei / Minqin Source: Sun Xuetao, 2022. Analysis on water resource Utilization in Minqin Oasis. China Water Conservance, Vol. 2022, No. 12: Table4 shows demand of water resource in the watershed in 2022. About 80% of water resource of whole watershed is used by Wuwei Oasis. In other word, Wuwei Oasis with times of GDP and times of population but times of cultivated land is consuming times of water resource than Minqin Oasis. Utilization of water resource and intensive farming in upstream region Allocation of water resource between upstream and downstream regions ? As water resource supply of whole watershed was relatively steady in past decades, increased occupation of water resource with industrial development and population growth in upper Wuwei Oasis caused a decline in water resource supply. ? Table5 indicates changes in water resource supply to downstream Minqin Oasis. Table5 Change in water resource supply in Minqin Oasis (downstream) Unit: 108m3 1940s 1956 1960 1970 1980 1990 2022 Runoff to Minqin 1940s 1957 1969 1976 1980 1990 2022 Runoff to Minqin 1940s 1950s 1960s 1970s 1980s 1990s 2022 Underground water supplement Sources: (1)Yang Yongchun, 2022. The Analysis of the Oasis Environmental Change and its Reason of the Lower Reaches of the Arid Region. Human Geography, , : (2) Sun Xuetao, 2022. Analysis on water resource Utilization in Minqin Oasis. China Water Conservancy, Vol. 2022, No. 12: In contrast with 1960, runoff to Minqin in 2022 has decreased 75%, from *108m3 to *108m3. The upstream region is enjoying the use of abundant water resource, but the downstream region is suffering a severe shortage of water resource. Driedup reservoir and irrigation canals in Minqin due to the decline in surface runoff and underground permeation from upper region Table6 Estimation of water resource demand and supply in Minqin in 1990s Unit: 104m3 Items Water resource supply Items Water demand Gap between supply and demand Total 29,676 Total 78,133 48,457 Surface runoff 15,010 Agriproduction needs 77,265 Underground water 11,290 Household living and industry needs 868 Precipitation 3,376 Items Usable water resource Items Actual use of water resource Gap between supply and demand Total 28,090 Total 78,133 50,042 Surface runoff 12,900 Surface runoff 12,900 0 Underground water 15,190 Underground water 65,233 50,042 Source: Yang Yongchun et al, 2022. The human mechanism research of Minqin Oasis change in the lower reaches of the Shiyang River. Geographical research, , : Gap between usable water resource and actual use of water resource ? Table6 shows the gap between usable water resource and actual use of water resource reaches at 500, 420*103m3. ? Especially, as surface runoff is limited, the way to fill in the gap is to draw underground water. Slim flow of canal in Minqin Difference in crop productivity between irrigated fields and nonirrigated fields Inpatibility between efficient utilization of water resource and technical and financial barriers ? As diverting water from other watershed cannot fill fundamentally in the gap, to adjust land use system and to improve efficiency of water resource utilization is the essential solution to relieve the gap between demand and supply of water resource. ? However, possibility to improve efficiency of water resource utilization is not so optimistic due to technical, financial and institutional barriers for smallholders to improve effic