Recharge and loss of groundwater during freezing-thawing period in inland basin, Northwestern China

In the plain located in the north slope of Tianshan Mountain, early November is the beginning of the freezing period, while early March next year is the beginning of the thaw period.And the freezing period is much longer than the thaw period.In the experimentation station of the groundwater balance, located in Changji County, three kinds of soil (stony sand, fine sand and clay), which are local typical soil in the inland basins, are chosen to observe the recharge and the loss of groundwater in freezing-thaw period.According to the critical depths of groundwater loss, several kinds of groundwater table are designed for all kinds of soil.In the freezing period, where the stony sand and sand are distributed, the protection of groundwater resources is favorable In the thaw period, no matter what depth of groundwater table, the recharge occurrs for all of the three, but the recharge of the fine grained soil is relatively less and shows the delaying effect.Contrarily, the coarse grained soil is more favorable for the formation of groundwater resources.The largest loss of groundwater is not beyond 25.3 mm in one month during the freezing period(for example, stony sand), and the largest recharge is more than 113.3 mm in the same time during the thaw period(for example, fine grained sand), so the thaw period is the important period of groundwater recharge each year.