LAUSR

Abstract A suitable oasis scale and a cultivated land scale are important for water resources management in arid regions. This paper developed an approach to calculate a suitable oasis scale and a cultivated land scale by combining water-heat balance theory and wind-sand dynamics theory with ecological health assessment (i.e., WHBEHA model). The oasis effective vegetation coverage was determined using the wind-sand dynamics theory. The oasis ecological health was assessed by constructing the ecological health index system. This index system considered groundwater depth, ratio of farmland shelterbelt, vegetation coverage status, and occurrence frequency of strong winds as ecological health evaluation indicators and was illustrated using the middle reaches of Heihe River basin as the case study. The results of the proposed WHBEHA model revealed that the most suitable ecological and cultivated areas under different hydrologic years were 363–442 km2 and 1450–1767 km2 in the middle reaches of Heihe River basin. They summed up to the total suitable oasis areas were in the range of 1813–2209 km2. Status quo 2013 was a high flow year, according to WHBEHA, the scale of cultivated land in 2013 has exceeded the suitable scale, and should be reduced by 334 km2. Compared with the current oasis scale based on land-use and land-cover information and the oasis scales computed using oasis water-heat balance and oasis circle theory (WHBOCT), the proposed WHBEHA model is more suitable by considering the factors that affect the ecological health of arid regions. Furthermore, this study may provide a guideline for determining a sustainable socio-economic scale, especially cultivated scale in arid regions.