Understanding the impact of mountain landscapes on water balance in the upper Heihe River watershed in northwestern China

Abstract

Estimating the impact of mountain landscape on hydrology or water balance is essential for the sustainable development strategies of water resources. Specifically, understanding how the change of each landscape influences hydrological components will greatly improve the predictability of hydrological responses to mountain landscape changes and thus can help the government make sounder decisions. In the paper, we used the VIC (Variable Infiltration Capacity) model to conduct hydrological modeling in the upper Heihe River watershed, along with a frozen-soil module and a glacier melting module to improve the simulation. The improved model performed satisfactorily. We concluded that there are differences in the runoff generation of mountain landscape both in space and time. About 50% of the total runoff at the catchment outlet were generated in mid-mountain zone (2,900-4,000 m asl), and water was mainly consumed in low mountain region (1,700-2,900 m asl) because of the higher requirements of trees and grasses. The runoff coefficient was 0.37 in the upper Heihe River watershed. Barren landscape produced the largest runoff yields (52.46% of the total runoff) in the upper Heihe River watershed, followed by grassland (34.15%), shrub (9.02%), glacier (3.57%), and forest (0.49%). In order to simulate the impact of landscape change on hydrological components, three landscape change scenarios were designed in the study. Scenario 1, 2 and 3 were to convert all shady slope landscapes at 2,000-3,300 m, 2,000-3,700 m, and 2,000-4,000 m asl respectively to forest lands, with forest coverage rate increased to 12.4%, 28.5% and 42.0%, respectively. The runoff at the catchment outlet correspondingly declined by 3.5%, 13.1% and 24.2% under the three scenarios. The forest landscape is very important in water conservation as it reduced the flood peak and increased the base flow. The mountains as "water towers" play important roles in water resources generation and the impact of mountain landscapes on hydrology is significant.

Assessing Variation in Water Balance Components in Mountainous Inland River Basin Experiencing Climate Change

“…First, the lack of field observation data-for example, soil moisture and actual evapotranspiration-hampers the validation of the simulation. Each landscape has different impacts on the hydrological process and in mountains, the water balance components vary in different landscapes [22]. Moreover, spatial heterogeneity of soil has great impact on the dynamic processes of hydrological systems.…”

“…The mountainous regions in inland river basins are very sensitive to climate change [22][23][24]. We choose the upper reaches of Heihe River Basin (HRB) as the study area.…”

Long Term Quantification of Climate and Land Cover Change Impacts on Streamflow in an Alpine River Catchment, Northwestern China

“…Today, high-quality land cover types can usually be acquired via remote sensing technology developed after the 1980s. Hydrological models, such as the SWAT [17,18], TOPMODEL [19], and VIC [20], are commonly used to study the effect of climate change on the hydrological cycle. Based on physical mechanisms, hydrological models offer a framework for conceptualizing and investigating the relationships between climate, land cover, and hydrological processes in various categories of time and space [21,22].…”

Frequency Analysis of High Flow Extremes in the Yingluoxia Watershed in Northwest China

“…The area of this watershed reaches 10,009 km 2 and its altitude ranges from 3300 m asl to 1700 m asl. About 50% of the total runoff at the watershed outlet is generated in the mid-mountain zone (>2900 m asl) [27]. With the decreasing of altitude, the annual mean precipitation decreases from 400 mm to 180 mm, and the annual mean temperature increases froḿ 3˝C to 7˝C.…”