Runoff pattern and adjusting measure of the karst slope for tanks

The formation and dynamics of slope runoff as karst aquifer recharge process are rarely described specially for the karst area of South China. A spring which discharge epikarst in Yaji experimental site was selected as the research point. The hydrological and hydrochemical dynamic process under different precipitation conditions were obtained through multi-parameter monitoring for a hydrological year. Understanding the dynamic characteristics of runoff formation conditions as well as water source composition of slope flow were formed using hydrological and hydrochemical analyzes. According research there are strong seasonal changes which reflected on the hydrological processes for slope runoff. The total duration of low water level is half of the year, the continuous duration is more than 3 months, and more than 40 days are continuous dry-up throughout one hydrological period. All this indicates instability and variability in slope runoff, and it is necessary to apply certain measures in regulating this process. The hydrochemical dynamics controlled by carbonate dissolution show the merging of runoff from different geological formation. The oscillation of electrical conductivity as well as other indicators show that the runoff formed in bare rock surface plays vary important role. According to the geological structure of slope area regulation through three approaches is proposed: reducing runoff leakage in bare rock area; improving permeability of the epikarst zone; exploring karst conduits in dolines. These measures will help to increase the storage capacity of water tank and improve the utilization efficiency of runoff.