Abstract:

Highway greenbelts can beautify the environment, absorb dust and noise, and conserve water and soil. However, in arid areas with low precipitation, highway greenbelts mainly rely on groundwater recharge, which would have certain impact on regional groundwater resources distribution. This paper takes the Hubao highway greenbelt in the northern part of the Tumochuan Plain as a case study. Based on the analysis of the groundwater recharge characteristics, 3S technology and the Penman formula are used to calculate the transpiration rates under different vegetation coverage along the highway greenbelt. Groundwater recharge and the impact of highway greenbelt construction on the distribution of groundwater resources in the Beijing-Tibet Expressway are then analyzed. The results show that groundwater in the study area comes mainly from lateral recharge of the Daqingshan Mountain. The main discharge is groundwater runoff and transpiration along the greenbelt. During the period of July 2016 to June 2017, the non-vegetation and vegetation covered parts (17% and 83% of the total area, respectively) of the study area has an annual evapotranspiration of 1,006.10 mm. Along the greenbelt, transpiration water consumption is of 2,434.86×10⁴ m³/a, and lateral recharge from the mountain front is of 24,372.16×10⁴ m³/a. The transpiration water consumption of the greenbelt accounts for 10% of the lateral recharge from the mountain, which shows that the construction of highway greenbelts has an important impact on the distribution of groundwater resources.

Key words: highway greenbelt, semi-arid region, vegetation transpiration, groundwater budget