Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Hydrological Estimations to Calculate Rain-water Harvesting Potentiality Using GIS and Remote Sensing : A Case Semi-arid Area, Gezira State, Sudan (1981-2018)

Auteur : Esraa Mergani Osman, Ali

Université de soutenance : University of Gezira

Grade : Master of Science (MS) In Water Management Water 2021

Résumé
The study aims to maximize the utilization of rainwater by applying water harvesting technique in semi arid areas where the rain falls irregularly and much of the precious water is soon lost as surface runoff by using Remote Sensing (RS) and Geographic Information Systems (GIS). Hegealig village is located east of Wad-Medani, in Gezira State. The residents depend on rainfed agriculture, which stop completely after the rainfall season. The Digital Elevation Model (DEM) is used to develop a drainage map for the area. Hecgeohms-HMS model connected to Arcmap 10.2 was used to analyze streams network and extract the characteristics of the different water basins in the study area. After conducting the analysis of the streams network, a main valley was identified that a large quantity of water from the north of the residential area heading east towards Al-Rahad River. A model of Curve Number was used, which was obtained after combining soil maps with land use. The surface runoff of the study area was evaluated using HEC-HMS model version 4.5 and the amount of rain for the return period (5, 10, 15 and 25 years) was predicted by the Hyfran plus software using the rain data obtained from Wad-Medani station for the period between (1981-2018). The Soil Conservation Service runoff model (SCS-CN) was used to estimate the potential runoff amount. Accordingly, the drainage of the valley under study was estimated 1.27 million m3/season of 5 years return period (2025) and about 1.9 million m3/season of 25 years return period (2045). A dam with Embankment high 4m and length 630 m, and free Board 8m with height 2 m was proposed to construct on the valley at a distance of 3 km from the residential area with a storage capacity of 425,000 m3, which was proposed after calculating water balance for the Hegealig region (water demand versus water supply), and planning to cultivate 100 feddan of vegetables and irrigated from the water of the dam after the rainy season in addition to continuous monitoring of the effect of the dam.

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