The worldwide growth of the population has noticeably increased the demand for natural resources, such as water, land, and food [1
]. On the other hand, climate change, caused by an increase in greenhouse gas emissions and global warming [3
], has created an overall decline in rainfall and thus drought problems. This is further exacerbated by anthropogenic activities, such as over-farming, excessive irrigation, deforestation, and the over-exploitation of available water resources [6
]. Consequently, climate change and the aforementioned anthropogenic activities may result in a reduction in freshwater resources that will, in turn, adversely affect the irrigation water availability and carrying capacity of the ecosystem [9
Agriculture is the backbone of the Sub-Saharan economy and has been mostly practiced under a rain-fed system that is rarely supplemented with irrigation. In such systems, irrigation plays a significant role in alleviating poverty and facilitating sustainable development [12
]. While water is one of the main factors that contribute to sustainable agricultural productivity, it also crucially contributes to the financial generation and economic growth of society [14
]. Consequently, developing an irrigation system and enhancing its efficiency would improve crop productivity, thereby reducing dependence on rain-fed agriculture [4
]. Several studies have proven that identifying the irrigation potential of an area could be a key factor to increase agricultural crop productivity [4
]. Intensive irrigation water use and the demand for crop production are also expected to alter the microclimate of the irrigated areas [15
]. Thus, alleviating poverty by practicing and enhancing irrigation systems, especially in developing countries (e.g., Ethiopia), is urgently needed.
Ethiopia has twelve major rivers that have significant water resource potential (about 122 Bm3
annual surface runoff and 2.9 Bm3
]. Despite this fact, the country remains insufficient for agricultural food production due to its dependence on the rain-fed system. Moreover, the rivers are characterized by uneven spatial and temporal distributions [19
]. Most of these rivers have trans-boundaries and flow to neighboring countries, such as Sudan and Egypt [20
]. Ethiopia’s Ministry of Water Resources (MoWR) has highlighted that irrigation should be optimized to its maximum potential in terms of both utilizing existing resources and expanding cultivable land areas [22
]. As a result, the total irrigated land of the country has increased from 160,000 ha (3%) to 250,000 ha (4.1%) for the period between 1990 and 2002 [16
]. Ethiopia has shown fast growth in the economy and is targeted to achieve food security by 2030.
Moreover, agriculture production, which is practiced by more than 80.5% of the population of the country (approximately about 80 million), has significantly contributed to the country’s economy [22
]. Furthermore, 65% of Ethiopia’s land is suitable for irrigation systems. However, much potential land has not yet been developed. Therefore, assessing the irrigation potential and land suitability for irrigation water use is vital for the development of irrigated agricultural planning and the improvement of agricultural productivity. According to the agricultural development of the country, irrigation technology and management practices play a significant role in economic growth [27
In Ethiopia, the current traditional agricultural production system and the progressive degradation of available natural resources, particularly in highly susceptible areas of the country, together with climate change, have increased the pervasiveness of poverty and food insecurity [16
]. This has been the main challenge in the country’s agricultural production sector. Therefore, understanding climate change’s impacts on land-use suitability and agricultural production, including assessing irrigation potential, plays a vital role in the irrigation development plan [29
]. Several studies have also documented the importance of multi-criteria evaluations on land decision making for a different type of irrigation system [30
]. Moreover, understanding the dynamics of land cover characteristics is a crucial factor to select an appropriate irrigation system for achieving sustainable water resources and irrigated agricultural production [2
]. This study employs Geographic Information System (GIS) and Multi-Criteria Evaluation techniques to estimate the irrigation potential and land suitability of the Anger River basin (Ethiopia) as a case study for enhancing irrigation systems under different climate conditions. The basin is one of the tributaries to the Abbay River basin. This study mainly aims to understand and estimate the potential land suitability of the basin for irrigation-based agriculture development by considering the different factors affecting land suitability. This study will help pave the way for further investigations and analyses of water resource potential and possibly required interventions for the study area.
4. Summary and Conclusions
This study assessed the irrigation suitability of the Anger River basin (Ethiopia) based on six irrigation suitability factors (distance to water resources or river, slope, land use/land cover, soil texture, drainage, and depth), including climate change impacts. Based on these multi-evaluation criteria and matrix, supported with GIS-tools application, the study successfully mapped the irrigation suitability and identified the potential irrigable areas of the basin for an optimized irrigation system [68
It is concluded that approximately 40% of the basin’s area can provide moderately to highly suitable conditions for surface irrigation systems. However, it is expected that future climate change may reduce the available water resources of the basin due to increases in temperature and evapotranspiration rate, and thus decrease in the estimated potential irrigable areas of the basin. This indicates the importance of implementing climate change mitigation measures, including enhanced surface irrigation systems to optimize the use of available water resources and irrigation water efficiency and improve the agricultural crop productivity of the basin. Therefore, this study could provide useful information for future water resources development and irrigated agricultural land plans of the basin whereby more than 85% of the basin’s communities depend on agricultural crop productivity.