Analyzing the Effect of Rainwater Runoff in Drainage Ditch II on Agricultural Fields in the Chókwè City
Keywords:
Hydraulic simulation, Rainwater, Flooding, Agricultural fields, Chókwè CityAbstract
Mozambique is vulnerable the effects of climate change, and in the south of the country, in the province of Gaza, specifically in the Chókwè city, floods occur frequently. Against this backdrop, activities were carried out to build a hydraulic passage that connects and integrates the drainage system of the urban centre of the Chókwè city with the agricultural drainage system in the Lower Limpopo irrigation system. To this end, it was necessary to carry out a study to analyze the effect of rainwater runoff in drainage ditch II on agricultural fields in the Chókwè city, in order to study its performance in the face of increased rainwater drainage flows. Hydrological studies were carried out to obtain maximum flows at four return times, applying the unit hydrograph method based on rainfall data adjusted by the Gimbel distribution model. The topographic data of the study area was collected using remote geoprocessing techniques. This data was used as input for the HEC-RAS 6.6 software to carry out the hydraulic simulation and map the areas prone to flooding. The results show that various areas of agricultural production are susceptible to flooding for all return times. The largest flood spot was found for the 25-year return time, occupying an area of 8,537km2, which corresponds to 55.80% of the area flooded, and the smallest was found for the 2-year return time, with an area of 1,306 km2.
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