Evaluation of MAR methods for semi-arid, cold
region
Nasanbayar Narantsogt,
Karlsruhe
University
of Technology, Karlsruhe Germany
Abstract:
The semi-arid and cold environment shows a high
variability in precipitation and river discharge. The groundwater aquifer
located near Ulaanbaatar
capital city of Mongolia, is the only source of water supply and it is
important to ensure that groundwater is available now and for the future.
The main watercourse near the city is the Tuul
River, fed by precipitation in the nearby Khentii Mountains. However, due to
the absence of precipitation during winter and spring, the riverbed usually
runs dry during that time, and observations show that the dry period has been
extending within the last years.
However, in parallel with the city’s development,
the extended groundwater aquifer shows a clear decline, and the groundwater
levels drop significantly. Therefore, a groundwater management system based on
managed aquifer recharge is proposed and a strategy to implement these measures
in the Tuul River valley is presented in this paper. It consists of an
enhancement of natural recharge rates during the summer wet period, an increase
of groundwater recharge through melting ice storage in dry period, as well as
the construction of underground dams to accumulate groundwater also surface water
reservoir which release constant discharge in outlet.
The MATLAB icing code written for ice storage on
limited and unlimited area was considered in FEFLOW simulation scenarios as water
source in ice form on surface to increase groundwater natural recharge rates
during the early dry period, through melting ice storages. The study of underground artificial
permafrost as ice dam was processed in FEFLOW simulation scenarios for accumulating
groundwater resources. The results of these artificial recharging methods
calculated individually and combined also compared with surface reservoir which
release constant discharge through dam.
