Study of suitable oasis scales based on water resource availability in an arid region of China: a case study of Hotan River Basin

The object of this study was to answer a scientific question, i.e., how to determine the suitable scale of natural and artificial oases management based on water resource availability in an arid region. For this purpose, the Hotan River Basin was chosen as the study area, we analyzed the distribution characteristics of natural vegetation in the river basin using remote sensing images, water resources, weather, socioeconomic data, and field survey data. We also divided the natural vegetation into two ecological protection targets: the major and the basic protection zones. Suitable scales of oasis management were calculated under different inflow variations based on the above analysis. We had five major findings. (1) The total area of natural vegetation of the river basin is 4968.87 km² with forestland, open forestland, high-covered grassland, and low-covered land accounting for 14.08, 14.98, 13.16, and 57.78 % of the total area, respectively. (2) In the middle reaches, the average vegetation distribution ranges for the west and east banks of the Yurunkax River are 5–8 and 34–51 km from the river, respectively. The average vegetation distribution ranges for the west and east banks of the Karakax River are 31–45 and 2–9 km from the river, respectively. In the lower reaches, the average vegetation distribution range is 3–10 km from the river. (3) During high-, normal-, and low-flow periods, the total available water for the river basin is 54.48 × 10⁸, 42.67 × 10⁸ and 34.00 × 10⁸ m³, respectively. (4) The ecological water demand of the Hotan River is 8.85 × 10⁸ m³, and the ecological water demands of the middle and lower reaches are 5.13 × 10⁸ and 3.72 × 10⁸ m³, respectively. (5) The optimal area for the natural oasis in the middle reaches is 3145–3293 km². This study provides a theoretical basis for planning rational development of similar river basins in arid regions.