A New Method for Runoff Water Trapping and Harvesting from the Catchment Area to Increase Water Productivity and Reduce the Sediments in Wadi El Raml-Northwest Coast - Egypt

Abstract

A new technique method for runoff water trapping and harvesting was applied and experimented to increase runoff water collecting and reducing the soil losses by decreasing the run-off flow time through dividing the long catchment area into several small catchments were separated by earth boundary and installing main access pipe that branched to sub main pipe towards every small catchment. The experiment was applied in the Northwest Coast, Wadi Al-Raml, during the winter seasons of 2021 and 2022. The study was conducted to determine the best parameters that give the best results in terms of surface runoff, water harvested productivity and soil losses estimator during runoff. The following treatments were applied: Three slopes for catchment areas (7%-10%-15%)and two angles of earth boundary (90°-120°) with a comparison to the traditional catchment area. The presented data showed that treatment T 6 which comprised (15 % slop of catchment with soil boundary angle 120°) achieved the optimum values of runoff,11.04 and 9.34 and runoff coefficient, 0.67 and 0.67 During two consecutive seasons. T 0 recorded lowest values of, 3 and 0.20 as annual average of runoff and runoff coefficient respectively. Concerning soil losses traditional treatment T 0 recorded the highest value of 1.20 tan.fed -1 , while treatment T 1 which comprised (7 % slop of catchment with soil boundary angle 90°) achieved the lowest and optimum value of 0.59 tan.fed -1 . In general, increasing catchment slope and earth boundary angle sustain increasing runoff flow and runoff coefficient