Rainwater Harvesting Potential in Different Treatments and Times on the Taleghan Watershed

Rainwater harvesting (RWH) in arid and semi-arid regions using micro-catchments (MCS) is an appropriate technique to produce crops and to deal with water shortages. The potential of RWH on the Taleghan Watershed was investigated using MCS covering areas of 100, 25, and 6.25 m2 under three treatments: furrowing, surface compaction, and control (no treatment) during the 2016/2017 hydrological year. The experimental design was a complete randomized block in a factorial manner with three replications. The volume of the collected runoff was measured after each precipitation event in different seasons. The relationship between the amount and coefficient of runoff (R and Cr, respectively) with precipitation and the threshold of precipitation for runoff production (TPR) was determined. Results showed that the spring precipitation produced 62.5 and 65.5% higher R than the winter and autumn rainfall, respectively. Moreover, surface compaction produced 17.3 and 19.8% higher R and Cr than the control, respectively; it also reduced TPR by 7%. However, under furrowing, the R and Cr values decreased by 22 and 20%, respectively; while, TPR increased by 4% more than the control. Furthermore, the values of R and TPR in larger MCS were less than those of the smaller MCS. Overall, the use of MCS for R harvesting and plant cultivation with surface soil compaction (increasing bulk density by 7%) is recommended in regions where their areas is determined by the plant type.