Groundwater recharge under irrigated agro-ecosystems in the North China Plain:From a critical zone perspective
Abstract
From a critical zone perspective, the present paper aims to present the magnitudeof groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose zone, evaluate the "time lag" effect of recharge, and underscore the role of a thickening vadose zone in recharge. The results indicated that different agricultural land-use types in the North China Plain need to be further considered in a recharge rate estimate, because agricultural land-use types lead to different recharge rates both in the piedmont plain and the central plain. Soil water residence time (several years) and groundwater level response time (several months) should be distinguished to further understand the processes of groundwater recharge, because the soil water displacement velocities range from 0.2 to 2.2 m/yr while the rate of wetting front propagation is approximately 47 m/yr in the piedmont plain. The thickening vadose zone would prolong the residence time of soil water and contaminant, which could postpone the time of or alleviate groundwater pollution, but have no significant influence on the magnitude of recharge in a long time scale. A r echarge coefficient based on a shorter time span (e.g. 2 or 3 years) should be used with caution as a parameter for groundwater resources evaluation, because it varies with total water input and target soil depth. Uncertainties in evapotranspiration and other water balance components should be evaluated in the recharge estimation and the impact of land-use types on recharge should be emphasized. The critical zone science would greatly improve the understanding of groundwater recharge processes. The results of the present study will be helpful in promoting sustainable groundwater resources management.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H53K1920M
- Keywords:
-
- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 1655 Water cycles;
- GLOBAL CHANGE;
- 1878 Water/energy interactions;
- HYDROLOGY;
- 1880 Water management;
- HYDROLOGY