[Vertical gradients of water supply and demand in Taihang Mountains, China]

Taihang Mountains plays a key role in water supply for the North China Plain, even though it has the ecological disadvantages of less water and soil. Research on the vertical characteri-stics of water supply and demand in Taihang Mountains is beneficial for the sustainable management of the mountain ecosystem. Here, we quantitatively evaluated water provision in the Taihang Mountains using remote sensing data and InVEST model. Water consumption was calculated according to the index of per capita comprehensive water use in different areas. The supply and benefit areas were scientifically demarcated based on water supply to demand ratios at different altitudes. The results showed that, from 2005 to 2014, the average volume of water yield and water consumption were 65.94×10⁸ and 45.32×10⁸ m³, respectively, with a surplus water volume of 20.62×10⁸ m³. On the county and catchment scales, there were water shortages in the low-altitude peripheral areas of the Taihang Mountains. However, the water shortage problem was inconspicuous for the overall mountain area, with a water supply to demand ratio of 1.53. Based on the variations in the water supply to demand ratio with respect to altitude, Taihang Mountains could be divided into three vertical bands. Areas with the altitude range of 0-300 m were water recharge areas, which were recommended for development as a complex agroforestry transition zone. Areas with the 300-950 m altitude range were water transfer balance areas, which were suggested as a maintenance zone retaining current levels of water production and consumption. Areas with altitudes greater than 950 m were water spillover areas, which should be designated for water conservation reserves with strict prohibitions regarding destruction.