刘君,陈宗宇*,卫文,张翼龙,李政红,刘福亮,郭华良
Abstract
The concentrations of chlorofluorocarbons
(CFC-11, CFC-12 and CFC-113) and tritium (3H) content in groundwater were used to
date groundwater age, delineate groundwater flow systems and estimate flow
velocity in the Hohhot basin. The estimated young groundwater age is fallen in
the bracket of 21 ~ 50 a and indicates the presence of two different age
profiles and flow systems in the shallow groundwater system. Older age waters
occur under the topographically low areas, where the aquifer is double-layer
aquifer system consisting of shallow unconfined-semi-confined aquifer and deep
confined aquifer. This reflects long flow paths associated with regional flow.
Groundwater (range from 21 to 34 years) in the north piedmont and east hilly
areas,where the aquifer is a single-layer aquifer consisting of alluvial fans,
are typically younger than those in the low areas. The combination of CFCs
dating with hydrogeological information indicates that both local and regional
flow systems are present at the basin. The regional groundwater flow mainly
flows from the north and east to the southwest, the local groundwater flow system
occurs nearby the Hohhot city. The mean regional groundwater flow velocity of
the shallow groundwater is estimated about 0.73 km/a. These findings can aid in
refining hydrogeological conceptual model of the study area.