Rainwater Collection in Natural Conditions an Approach for Solving Water Shortage in Arid and Semi - Arid Zones (Case Study: Latian Watershed - Iran)

One of the important problems of arid and semi-arid zones, for developing of these regions and especially villages located in these climates, is insufficient rainfall or shortage of water. In these regions often the rainfall is in winter and early spring. Also because of high rating of precipitation of these regions the rainwater or runoff is going out very fast without any reasonable using. It is clear that by increasing the population more crop production via increasing of fruit trees and woody trees is necessary. One of the methods of increasing irrigated farm is small scale farming, rainwater collecting and supply collected rainwater in root zone and separated pool for reservoir of supplementary irrigation in summer. This research, which has done in Latian Watershed, had 12 plots with area 40 to 70 sq/m. Slope of these plots were 3 groups, 2-20, 21-40, 41-60 percent and vegetation conditions were also 3 groups, as 10-30, 31-50 and 51-70 percentage coverage by natural grass. 12 times of daily rainfall and it's runoff separately measured in these plots. Depth of runoff was 55 to 104 mm from 375 mm rainfall in 12 days per year. The results showed that treatments of vegetation and slopes have significant difference in 95% of accurance. Maximum depth of runoff observed from 41-60% slope treatment and 10-30% vegetation coverage. More slope place was suitable for runoff collecting and level part or low slope is quite for trees planting and infiltrating of runoff.