Purpose: to assess quantitatively the impact of irrigation water withdrawals on water resource availability and dynamics in the Chari River basin.
Materials and methods. The methodology combines the analysis of historical hydrological data, remote sensing for mapping the irrigated zone expansion, and simple water balance models. The object of the study was the Chari River watershed area, located in the Republic of Chad, where the bulk of the country's agricultural land is concentrated. Irrigated areas were identified using the normalized vegetation index and soil moisture index, based on 30-year series of daily and monthly water discharges of the Chari River. Field surveys were conducted in 150 farms in the irrigated perimeters to collect information on crop types, irrigation schedules, and irrigation methods.
Results. With the increase of the irrigated area in the basin from 45,000 hectares to over 120,000 hectares over a 20-year period, i.e. of almost 2.7 times, a significant reduction in the Shari River's flow was observed, more pronounced during the dry season (February to May). The average minimum monthly discharge decreased over this period from 350 to approximately 220 m³/s, while annual water withdrawals for irrigation increased from 0.45 km³/year in 2000 to 1.25 km³/year in 2020. This situation aggravates the resource vulnerability which is already under threat from the climate change impacts and the recurring droughts that severely impact Africa.
Conclusions. To combine agricultural development and the preservation of the river ecosystem, priority measures, namely, modernizing irrigation systems to improve their efficiency (drip irrigation and sprinkling irrigation); creating a strict regulatory framework for drilling new wells and collecting water; promoting less water-intensive crops adapted to climate change; and strengthening hydrological and agricultural monitoring systems to improve decision-making, have been formulated.
the Chari River, Chad, irrigation, water resources, impact, management, watershe
Glazunova I. V., Burku B. Impact of Irrigation on the Water Resources of the Chari River in the Republic of Chad. Ways of Increasing the Efficiency of Irrigated Agriculture. 2025;97(3):154–163. (In Russ.).
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