The annual runoff coefficient is one of the most important factors for the design and construction of dams. the runoff coefficient determines the possible storage capacity in front of the dam and thus the size of the dam to be constructed to be technically and economically feasible. In this study, the annual mean runoff coefficient of Hadramout coast basins was calculated based on previous studies of surface runoff of Wadi Hadramout valleys. Using the statistical program (IBM SPSS Statistics 20), a mathematical relationship was established to calculate the annual runoff coefficient based on the specifications of Hadramout coast basin and a basin group in Saudi Arabia , which are known. These basins are similar to Hadramout coast. The relationship is : Rc = 0.035 P - 0.025 A + 1.16 Sm Where A: basin area (1000 Km2) , and P : annual mean precipation (mm) And Sm : basin slop % , Rc - Annual runoff coefficient % The calculation results of runoff coefficients were compared according to the derived relationship with the values of runoff coefficients of the mentioned basins and the results were close. We note from the relationship that the annual runoff coefficients increase with the increasing in the precipitation rates as well as with the increasing in the basin slop, and they decrease with the increasing area. This relationship can be used in similar areas and different precipitation rates.
Alsouck, Ghazwan Sheikh and Algifry, Mohammad Husain
"The mean annual runoff coefficient at streams in south region of Hadhramout, Yemen,"
Hadhramout University Journal of Natural & Applied Sciences: Vol. 15:
1, Article 8.
Available at: https://digitalcommons.aaru.edu.jo/huj_nas/vol15/iss1/8