Analysis of irrigation water requirements in Gezira scheme using geographic information systems : case study block number 26 (Dolga)‎

الملخص EN

Water scarcity has a direct impact on food security and a real threat to food production for millions of the population.

To avoid the unwise and random consumption of available water resources, it is high time for using efficient system and appropriate policies for management of irrigated farms to control water overuse, starting by the analysis of the existing reality.

Block number 26 (Dolga) in Gezira scheme had been chosen as a study area.

The total area of the study area is about 24616 Feddans.

The study aims to apply GIS in the data editing, manipulation, storage, processing, and presentation for the analysis of irrigation water requirements.

GIS had been chosen for its capabilities of data capturing, data processing and efficient spatial analysis.

Layers of geo-referenced spatial database including crops’ maps, irrigation canals network and its command area, each crop water requirements, irrigation water requirement, rainfall data, area cultivated for each crop and contour map of the study area had been created and used for the spatial analysis in ArcGIS software.

Five course rotations are applied for the crops of cotton, wheat, sorghum, and groundnut.

Each crop covers 20% of the total area and the remaining 20% are fallow and layer for each crop had been created.

Crops’ water requirements had been calculated applying Penman-Monteith method and saved in the attributes Table of crops layer.

It had been found that the seasonal crop water requirements per Feddan for each crop is 3,871.56 m3, 2,983.26 m3, 1,847.16 m3 and 2,007.6 m3 respectively, calculated using Penman-Monteith method.

The total crops water requirements are 50,254,962.66m3(absorbed by plants), water allotment of the study area according to the ratio of the area is 67, 195,230.327 m3, irrigation water requirement is 64,537,716.5 m3 (including the water losses), where the actual water supply is 63,817,600 m3 which had been calculated applying ArcGIS tools and saved in the attribute Table of the crops and rotation layer.

The study had concluded that cotton consumes the largest amount of water supply, rainfall water is in irrigation has the used only in the complementary irrigation of sorghum crop and the implementation of GIS capabilities enables efficient analysis and scheduling of irrigation water.