Presentation


The Nile Basin Development Challenge (NBDC) is one of six global focal basins of the Challenge Program on Water and Food (CPWF). The overall objective of the CPWF program is to increase water productivity and resilience of social and ecological systems, through broad partnerships and research that leads to local impact and wider change.
Within this framework, the NBDC has set out to improve and build on rainwater management strategies as a way to improve livelihoods and reduce poverty. The focus of the work has been on the Blue Nile where rainfed agriculture dominates and over 80% of the population relies on subsistence, rainfed agriculture. In contrast, the downstream countries, principally Egypt and Sudan, are dominated by large-scale irrigated agriculture. However they will also potentially benefit from improvements in rainwater management upstream through reductions in land degradation and associated soil erosion which when transported downstream reduces the efficacy of irrigation schemes.

To meet the Nile Basin Development Challenge, it was found necessary to adopt an outcome logic model in which a range of approaches have been used to generate outputs and outcomes to support policy development and enhance best practices in relation to selected land management. These are briefly presented in summary here with subsequent papers in the proceedings developing the issues in greater a depth.

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This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

The hydrology of Holetta River and its seasonal variability is not fully studied. In addition to this, due to scarcity of the available surface water and increase in water demand for irrigation, the major users of the river are facing a challenge to allocate the available water.

Therefore, the aim of this research was to investigate the water availability of Holetta River and to study the water management in the catchment. Soil and Water Assessment Tool (SWAT) modelled the rainfall runoff process of the catchment. Statistical (coefficient of determination [R2], Nash- Sutcliffe Efficiency Coefficient [NSE] and Index of Volumetric Fit [IVF]) and graphical methods used to evaluate the performance of SWAT model.

The result showed that R2, NSE and IVF were 0.85, 0.84 and 102.8, respectively for monthly calibration and 0.73, 0.67 and 108.9, respectively, for monthly validation. These indicated that SWAT model performed well for simulation of the hydrology of the watershed. After modelling the rainfall runoff relation and studying the availability of water at the Holetta River, the water demand of the area assessed. CropWat model and the survey analysis performed to calculate the water demand in the area. The total water demand of all three major users was 0.313, 0.583, 1.004, 0.873 and 0.341 MCM from January to May, respectively. The available river flow from January to May obtained from the result of SWAT simulation. The average flow was 0.749, 0.419, 0.829, 0.623 and 0.471 MCM from January to May respectively. From the five months, the demand and the supply showed a gap during February, March and April with 0.59 MCM.

Therefore, in order to solve this problem alternative source of water supply should be studied and integrated water management system should be implemented.

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This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

The current paper discusses the use of hydrological modelling tool to understand sustainable land management interventions in the Blue Nile basin of Ethiopia.

A micro-watershed named Mizewa with a drainage area of 27 km2 in Fogera district was selected and instrumented with hydrological cycle observation networks in the year 2011. The SWAT hydrological modelling tool was used to simulate landscape-wide Soil and Water Conservation (SWC) investments.

Simulations of the selected investments modelled in this analysis suggest that improvements in infiltration, decreases in surface runoff and decreases in erosion are achievable in the watershed. Further simulations suggest that a landscape-wide approach of terrace and bund construction has the greatest effect in terms of decreasing surface runoff, decreasing sediment yield and increasing groundwater flow and shallow aquifer recharge.

A comprehensive landscape investment of terraces on slopes greater than 5% and bunds maintained on slopes less than 5% would decrease surface flow by almost 50%, increase groundwater flow by 15% and decrease sediment yield from erosion by 85%. However, constructing terraces in areas with greater than 5% slope (without constructing bunds in areas under 5% slopes) has a similar effect whereby surface flow and sediment yield decreases by 45 and 83%, respectively and groundwater flow increases by 13%. Residue management also has a significant effect on surface flow and erosion in the Mizewa watershed. Average annual surface flow decreased 17 when adopting residue management on all agricultural land and 26% when coupling terracing on steep slopes with residue management in mid-range slopes.

These analyses provide the foundation for understanding feasible outcomes given a more comprehensive investment strategy. Results stemming from the current work can be paired with household level socio-economic data in order to assess program investment alternatives taking into account household constraints to Sustainable Land and Watershed Management (SLWM) investment and maintenance on private and public lands.

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This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

Termites are a major pest in the semi-arid and sub-humid tropics. They pose a serious threat to agricultural crops, forestry seedlings, rangelands and wooden structures. In Ethiopia the problem is particularly serious in the western part of the country, specifically in Wollega Zones of Oromia Region. In the past, several attempts were made to reduce damage caused by termites, including extensive termite mound poisoning campaigns. These interventions not only had a negative effect on the environment, but were also largely ineffective.

Based on previous work in Uganda showing that adding organic matter to the soil diverts termites from the plant and functions as alternative feed source, a project was commenced by the Challenge Program for Water and Food (CPWF). In partnership with IWMI and Makerere University, ILRI and Wollega University took the lead in working with local stakeholders to identify sustainable solutions to address the termite problem in Diga, Ethiopia. The research consisted of two major activities; 1) a baseline study to better understand the relation between land use, water, termites and local institutions; and 2) the design and testing of identified interventions.

The baseline findings indicated that termite damage depends on various biophysical and socio-institutional factors, which requires an integrated, but also targeted, termite management approach; two termite species are locally recognized, but level of knowledge highly varies among farmers within and between kebeles. Various trials were designed for on-farm experimentation using cattle manure and crop residues as alternative feed source for termites in combination with other cultivation techniques.

The result obtained indicated that application of cattle manure and crop residues increases the organic matter content of the soil by 24.5 and 13.9%—grain yield of maize by 38.8 and 16.7% and reduces termite count per plant by 29.6 and 21.6% as compared to the control treatment, respectively. The results are in line with farmers’ own evaluation of the trials. Results and implications are discussed.

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Read the technical report No. 9 “Integrated termite management for improved  rainwater management: A synthesis of African experiences


This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

Most farmers in the Blue Nile Basin depend on unreliable rainfed agriculture and are vulnerable to climate variability. Lack of appropriate rain water management in these areas prevents smallholders from addressing the consequences of flooding during the rainy season and droughts during the dry season. This is in turn a major contributory factor to food insecurity and poverty.

Addressing these issues entails designing, targeting and prioritizing rain water management strategies. In support of this, we developed a generic methodology for out-scaling and prioritizing interventions in agricultural systems. The methodology entails a multi-stage and iterative process of:

  1. diagnosis and selection of options,
  2. characterization of the options,
  3. identification of the recommendation domains and out-scaling potential of these options,
  4. assessing the impacts along different dimensions and on different groups of people.

This paper describes how we applied this methodology in the Blue Nile Basin. We consulted several national stakeholders and identified the ‘best-bet’ options as they are currently being promoted by the SLM program. A next step entailed the description and characterization of the options. Previous knowledge about bio-physical and socio-economic conditions influencing suitability was collated, while field studies were undertaken to increase our understanding of adoption of these options. Matching this characterization data with a spatial database allowed us to map the suitability and feasibility of rainwater management options and strategies. For the last stage, the impact assessment, we identified the most-likely-to-be-adopted strategy for each of the watersheds based on the feasibility maps. We translated this into maps compatible with the SWAT model.

Results from the impact assessment should eventually feed back into the assessment of alternative options. The framework is applicable in many different forms and settings. The steps can be gone through qualitatively in a multi-stakeholder setting while the process can also be done quantitatively. It has a wide applicability beyond the Blue Nile Basin.

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See the full proceedings of the NBDC Science meeting


This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

Understanding soil hydraulic properties is crucial for planning effective soil and water management practices.

A study was conducted to evaluate the effects of different biochar and charcoal treatments on soil-hydraulic properties of agricultural soils. Biochar and charcoal treatments were applied on 54, undisturbed soil-columns, extracted from three-elevation ranges, with replications along three transects. Daily weight losses of freely draining soil-columns and soil moisture contents, at five tensions, were measured. In addition, field infiltration tests and soil analyses for particle size distribution, bulk-density and organic carbon content were conducted. Moreover, five year event precipitation data, from the watershed, was analysed and exceedance probability of rainfall intensity was computed.

Results show treatments reduced soil moisture contents, for most of the cases. However, treatment effects were significant only at lower tensions (10 and 30 kPa) and within two days after saturation (p<0.05). On the other hand, relative hydraulic conductivity (Kr) coefficients, near saturation, of amended soils were higher than the control. Acidic to moderately acidic soils with high average clay (42%) and low organic carbon contents (1.1%) were dominant. Infiltration rate ranged between 1.9 and 36 mm/h, with high variability (CV = 70%). At the same time, storms with short duration (< 15 min) and high average intensity (6.3 mm/h) contributed for 68% of annual precipitation (1616mm/year).

Dominant soil properties and rainfall characteristics suggest that infiltration could be a major problem on considerable number of fields, in the watershed. This implies, on such fields, constructing physical soil and water conservation structures alone will not reduce runoff and erosion effectively, unless soil infiltration and permeability rates are enhanced through integrated soil management approaches.

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This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

This study uses Tobit and Logit models to examine the impacts of selected small-scale irrigation schemes in the Lake Tana basin of Ethiopia on household income and the likelihood of poverty, respectively.

Data for these analyses were collected from a sample of 180 households. Households using any of the four irrigation systems had statistically significantly higher mean total gross household income than households not using irrigation. The marginal impact of small-scale irrigation on gross household income indicated that each small scale-irrigation user increased mean annual household income by ETB 3353 per year, a 27% increase over income for non-irrigating households.

A Logit regression model indicated that access to irrigation significantly reduced the odds that a household would be in the lowest quartile of household income, the poverty threshold used in this study. Households using concrete canal river diversion had higher mean cropping income per household than those using other irrigation types.

Key challenges to further enhancing the benefits of irrigation in the region include water seepage, equity of water distribution, availability of irrigation equipment, marketing of irrigated crops and crop diseases facilitated by irrigation practices.

See the presentation:

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See the full proceedings of the NBDC Science meeting


This paper was first presented at the Nile Basin Development Challenge Science meeting. The NBDC Science meeting was held on 9 and 10 July 2013 at the ILRI-Ethiopia campus, with the objectives to exchange experiences and research results across NBDC scientists involved in the NBDC projects and to discuss challenges and possible solutions.

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