Groundwater Based Irrigation and Food Security in Raya-Kobo Valley, Northern Ethiopia

The Raya-Kobo valley is characterized by good groundwater resources potential (excess of 198 Mm3) located in northern Ethiopia. The total area of the valley is approximated to be 3510 Km2. Despite this potential of groundwater, the area has been suffering from droughts. Establishment and expansion of cooperative societies, small business enterprises and irrigation farming were given priority as interventions to address the food security problem in the valley. These interventions were designed and implemented in the last several years by the regional governments administrating the Raya-Kobo valley, and groundwater is used as a source of water for irrigation farming for more than nine to ten years. Nevertheless, food insecurity is still a major problem in the area. The present study has been conducted to investigate the extent of contribution of the groundwater based intervention in the elimination food insecurity. The study was conducted by collecting, analyzing and interpreting all the existing relevant data of the study area. Groundwater potential was compiled from the author’s previous works and recently conducted research works. The impact of the groundwater based irrigation on food security issues was assessed using informal and formal interviews and focus group discussions. Limited area coverage of the irrigated land and the long time taken for the extension works in those drilled productive wells are the major limitations in the Kobo valley that makes the groundwater based irrigation unable to release the farmers of the area from the food insecurity. In Raya valley, besides to these problems, absence of responsible office, failure of pump, and the long time taken for pump maintenance are also the major factors. In Raya-Kobo valley food security is highly related to the availability of water. Irrigating the whole potential irrigable area, increasing and sustaining availability of groundwater and management of the irrigation scheme are vital to eradicate food insecurity from Raya-Kobo valley

Vortex Impeller-Based Aeration of Groundwater

Iron oxidation and removal from groundwater is a necessary and costly process in drinking water production. In most cases, iron removal is done via aeration, succeeded by precipitation. Most systems for aeration are based on increasing the interfacial area via injecting air in the system or spraying. Both methods have disadvantages, like clogging and formation of aerosols. In this study, a new vortex-based flow-through reactor consisting of a cylindrical tank with an impeller located at the bottom was studied regarding its aeration and iron oxidation capabilities in groundwater. During the aeration experiments, the flow rate, impeller rotation and aerated volume were varied. A nondimensional constant α was proposed to relate the system’s physical characteristics and its aeration capabilities, expressed in dissolved oxygen and system volumetric mass transfer coefficient (KLa). Three distinct operational regimes were defined: formation, complete and bubble regime. These regimes showed very specific characteristics regarding the air–water interface structure and the area to volume ratio, resulting in different aeration capabilities and iron oxidation efficiency values. The system presented KLa values similar to commercially available aeration systems, especially inside the bubble regime. By using dimensionless coefficients, the presented analysis provided the basis for the design of continuous impeller aeration and oxidation systems of arbitrary size

Requirements for Sustainable Irrigated Agriculture

The aim of this review is to present a holistic view on irrigation with respect to local environmental and social conditions. Future irrigation development is addressed with a focus on sustainable development. However, technical irrigation aspects are included and references are provided for further reading and completeness. An irrigation intervention is always a combination of feasible technical, social and environmental aspects. This review provides an overview of the various fields of expertise involved in irrigation interventions and contributes to cross-discipline discussions and understanding. The selected cases demonstrate the bias of human developments and they serve to raise awareness of the impact of human interventions. The practical examples refer mainly to the authors’ project experiences and were selected so as to support pathways for sustainable irrigation development. Placing modern irrigation in relation to sustainable development goals needs a sophisticated holistic approach

Requirements for Sustainable Irrigated Agriculture

The aim of this review is to present a holistic view on irrigation with respect to local environmental and social conditions. Future irrigation development is addressed with a focus on sustainable development. However, technical irrigation aspects are included and references are provided for further reading and completeness. An irrigation intervention is always a combination of feasible technical, social and environmental aspects. This review provides an overview of the various fields of expertise involved in irrigation interventions and contributes to cross-discipline discussions and understanding. The selected cases demonstrate the bias of human developments and they serve to raise awareness of the impact of human interventions. The practical examples refer mainly to the authors’ project experiences and were selected so as to support pathways for sustainable irrigation development. Placing modern irrigation in relation to sustainable development goals needs a sophisticated holistic approach

Adoption of Conservation Agriculture in Uganda: A Case Study of the Lango Subregion

Conservation agriculture (CA) is based on three principles: minimum soil disturbance, maintaining a soil cover through mulching with crop residues or planting cover crops, and practicing crop rotations. CA is practiced in many parts of the world for its benefits to soil and ability to improve yields, among others. There is little documented information on the status of CA adoption in the Lango region in mid-Northern Uganda. This study aimed at determining the extent of CA adoption in relation to the socioeconomic status of the farming population and suggesting relevant strategies for accelerating CA uptake specific to this region. A non-discriminative snowball-sampling technique was used to gather data from 417 households spread over three districts. Semi-structured interviews were conducted using household questionnaires. Farmers’ uptake of CA was related to information gained from training and the benefits that were observed in their fields. Some farm-level constraints in the region included the diminutive ratio of shared tools and equipment; the minimum presence and involvement of extension services; and seasonal rural markets that are dominated by middlemen. The impact that was attributed to the use of CA at the household level was improved yields. The strategy that was used to spread CA information to farmers also played a key role in increasing CA uptake in the region. This information is important for increasing CA adoption in this context given the socioeconomic status of the region

Hydrochemical characterization of various surface water and groundwater resources available in Matahara areas, Fantalle Woreda of Oromiya region

Study region: The Matahara region is located in the East Showa zone of Oromiya regional state (Ethiopia). Matahra Sugar Estate and Lake Basaka (highly saline, alkaline and sodic lake) are situated within the flat plains of Matahara region. The area is vulnerable to the occurrences of various tectonic and volcanic activities due to its location in the upper most part of the Main Ethiopian Rift Valley region. Study focus: In this study, the hydrochemical properties of different surface water and groundwater bodies available at Matahara region have been characterized for quality compositions. Water samples were collected from different water sources and analyzed for important major quality parameters following standard test procedures. Other chemical indices were derived from the measured quality parameters. The potential sources of minerals were suggested for each of the considered water sources based on their quality characteristics. New hydrological insights for the region: Overall, the study result elucidates that the chemical composition of different water bodies are due to natural processes and/or anthropogenic activities within the region. The local anthropogenic processes could be discharges from factory, domestic sewage and farming activities. Some of the water types are found to have relatively higher concentration of dissolved constituents. Irrigation waters have almost equal chemical compositions, indicating their hydrochemical sources are almost the same. Most of the concentrations are relatively high in Lake Basaka, groundwater and hot springs. It is easy to imagine the potential damaging effects of such quality waters on crop production, soil properties and environment of the region. Keywords: Chemical composition, Chemical indices, Lake Basaka, Matahara, Natural processe

Status of Groundwater Table Depth Under Long-Term Irrigation in Wonji Plain: Concerns for Sustainability of Wonji-Shoa Sugar Estate, Upper Awash Valley, Ethiopia

The present study attempted to highlight the concerns of shallow groundwater table depth (GWTD) to the sustainability of Wonji-Shoa Sugar Estate (WSSE), Upper Awash Valley of Ethiopia. The recent magnitude and fluctuation of GWTD is mapped in ArcView GIS (using universal kriging technique) from the monthly GWTD monitoring data (2007-2009) using piezometer tubes. The study result clearly showed that the GWTD at WSSE was extremely shallow, showed great spatio-seasonal variability and rising trend; thus, threatening the sustainability of WSSE significantly. About 90% of the plantation fields have GWTD above the critical depth of 1.5 m below the soil surface and, hence, critically waterlogged. As a result, the estate is recently achieving only 55% of the production potential realized in the 1960s. Past trends indicate that the GW has the potential to inundate Wonji plain and is anticipated to devastate production during the next 10-15 years. Therefore, in order to sustain production system in the region, there is an urgent need to identify the possible causes of waterlogging and investigate the feasible remedial measures to combat its problems. The spatial mapping of GWTD with identified problematic areas, indicated in the current study, is believed to provide a tool for water management and, hence, crucial for the decision making and actions taking processes