Papers by khalid hassaballah
<p>Skillful weather and climate forecasts, if utilized effectively, have th... more <p>Skillful weather and climate forecasts, if utilized effectively, have the potential to improve preparedness and disaster risk reduction. Forecast-based Action (FbA) is a framework for aiding decisions on preparedness in advance of weather/climate hazards, through use of forecasts. Here, we present a summary of research results and pilot project work within the Arid and Semi-Arid Land (ASAL) areas of Kenya conducted under the Towards Forecast-based Preparedness and Action (ForPAc) project. We also present opportunities for scaling up FbA  across the Greater Horn of Africa region through leveraging on connected projects and initiatives like Down2Earth.  Skill assessment of a pool of weather/climate models has established the most skilful multi-model combinations for monthly-seasonal timescale.  Co-production initiatives between forecast users and producers established the forecast variables best aligned with Kenya’s existing Drought Early Warning Systems (DEWS); Standardized Precipitation Index (SPI), Vegetation Condition Index (VCI) and soil moisture, as well as optimum forecast delivery time required by the DEWS processes. Our analysis shows that rainfall forecasts have skill across ‘seamless’ sub-seasonal to seasonal lead times, offering the potential to improve the anticipatory actions within the DEWS of Kitui county of Kenya. Working with multiple stake-holders from across local and national government, humanitarian agencies, forecasting services and climate researchers, we have explored the potential for a more anticipatory, proactive DEWS using forecast information. The Down2Earth project, which aims at translating climate information for adaptation and climate-resilience across decision-making levels is leveraging on gains of ForPAc by advancing FbA approaches within the rural communities of Kenya, Somalia and Ethiopia. To facilitate the institutionalization of FbA, we have developed a regional roadmap to guide implementation within National, regional and international humanitarian actors.   </p>
<p>Early warning of drought conditions can help protect lives and livelihoo... more <p>Early warning of drought conditions can help protect lives and livelihoods, especially in dry regions of subsistence agriculture and pastoralism. Regions such as the Horn of Africa Drylands (HAD) may benefit from advance warning of changes to available water supplies, as rural communities make critical decisions about planting and moving livestock at particular points in time. However whilst the regionally-mandated seasonal forecast for HAD provides information on rainfall totals, it does not quantify expected impacts on water balance components such as soil moisture and groundwater storage. This latter information may be more useful to rural communities who rely on groundwater for water resources for humans and livestock, and soil moisture for crop growth. These hydrological quantities can typically be estimated with hydrological models, but in drylands the processes governing water partitioning are complex and largely unrepresented in most existing regional and global hydrological models. </p><p> </p><p>Here we leverage the capability of a dryland-specific hydrological model (DRYP) to produce rainfall-driven water security forecasts for HAD. DRYP incorporates spatially varying rainfall and evaporative demand, dynamic surface-groundwater interactions, ephemeral flow through channels and focused groundwater recharge. We employ DRYP in a pilot application to produce seasonal forecasts of soil moisture and groundwater recharge for a large catchment within the HAD. We use the objective seasonal forecasts provided by the IGAD Climate Prediction and Application Centre (ICPAC) and disseminated within the Greater Horn of Africa Climate Outlook Forum (GHACOF). Methodological approaches to integrate DRYP with the regional climate outlook disseminated by ICPAC are described, along with evaluation of potential skill of these new water security forecasts for the regional pilot catchment. Finally, we describe and update on an active forecast pilot activity, where water security forecasts for the current rainfall season (March-May 2022) have been co-produced with ICPAC and disseminated to stakeholders in February 2022 as part of the GHACOF event, now publicly available via the ICPAC East Africa Hazards Watch platform, under the EU H2020-funded DOWN2EARTH project. Co-design activity arising from recent stakeholder workshops will be described.</p>
The Authors highly appreciate the suggestions and constructive criticisms posed by the reviewers.... more The Authors highly appreciate the suggestions and constructive criticisms posed by the reviewers. We also would like to thank the editor Dr. Uwe Ehret for handling the review process of the manuscript. Here we present our response to the discussion issues that have been arisen during the review process.
Land Degradation in the Dinder and Rahad Basins, 2021
Land Degradation in the Dinder and Rahad Basins
Land Degradation in the Dinder and Rahad Basins
The Authors highly appreciate the suggestions and constructive criticisms posed by the reviewers.... more The Authors highly appreciate the suggestions and constructive criticisms posed by the reviewers. We also would like to thank the editor Dr. Uwe Ehret for handling the review process of the manuscript. Here we present our response to the discussion issues that have been arisen during the review process.
Water Resources Management, 2012
The aim of this paper is to develop a methodology based on coupled simulation-optimization approa... more The aim of this paper is to develop a methodology based on coupled simulation-optimization approach for determining filling rules for the proposed Mandaya Reservoir in Ethiopia with minimum impact on hydropower generation downstream at Roseires Reservoir in Sudan, and ensuring power generation at Mandaya Reservoir in Ethiopia. The Multi-Objective Optimization (MOO) approach for reservoir optimization presented in this paper is a combination of simulation and optimization models, which can assist decision making in water resource planning and management (WRPM). The combined system of reservoirs is set in MIKE BASIN Simulation model, which is then used for simulation of a limited set of feasible filling rules of the Mandaya reservoir according to the current storage level, the inflow, and the time of the year. The same simulation model is then coupled with Multi-Objective optimization Non-dominated Sorting Genetic Algorithm (NSGA-II), which is adopted for determining optimial filling rules of the Mandaya Reservoir. The optimization puts focus on maximization of hydropower generation in both the Mandaya and the Roseires Reservoirs. The results demonstrate that optimal release-(and correspondingly filling-) rules for Mandaya Reservoir which maximize the hydropower generation in both Mandaya and Roseires reservoirs can be found. These rules are determined along the Pareto frontier obtained by the optimization algorithm, which can serve as a decision support tool for choosing the actual filling rule. The results also showed that the NSGA-II is an efficient and powerful tool that could assist decision makers for solving optimization problems in complex water resource systems.
Environmental Processes
Understanding the spatiotemporal dynamics of surface water in varied, remote and inaccessible iso... more Understanding the spatiotemporal dynamics of surface water in varied, remote and inaccessible isolated floodplain lakes is difficult. Seasonal inundation patterns of these isolated lakes can be misestimated in a hydrodynamic model due to the short time of connectivity. The seasonal and annual variability of the Dinder River flow has great impact on what is so called Mayas wetlands, and hence, on the habitats and the ecological status of the Dinder National Park. This variability produces large morphological changes due to sediment transported within the river or from the upper catchment, which affects inflows to Mayas wetlands and floodplain inundation in general. In this paper, we investigated the morphological dimension using a quasi-3D modelling approach to support the management of the valuable Mayas wetlands ecosystems, and in particular, assessment of hydrological and morphological regime of the Dinder River as well as the Musa Maya. Six scenarios were developed and tested. Th...
Hydrological Processes
Understanding the natural low flow of a catchment is critical for effective water management poli... more Understanding the natural low flow of a catchment is critical for effective water management policy in semi-arid and arid lands. The Geba catchment in Ethiopia, forming the headwaters of Tekeze-Atbara basin was known for its severe land degradation before the recent large scale Soil and Water conservation (SWC) programs. Such
International Journal of Hydrology Science and Technology
Hydrology and Earth System Sciences
Understanding the land use and land cover changes (LULCCs) and their implication on surface hydro... more Understanding the land use and land cover changes (LULCCs) and their implication on surface hydrology of the Dinder and Rahad basins (D&R, approximately 77 504 km 2) is vital for the management and utilization of water resources in the basins. Although there are many studies on LULCC in the Blue Nile Basin, specific studies on LULCC in the D&R are still missing. Hence, its impact on streamflow is unknown. The objective of this paper is to understand the LULCC in the Dinder and Rahad and its implications on streamflow response using satellite data and hydrological modelling. The hydrological model has been derived by different sets of land use and land cover maps from 1972, 1986, 1998 and 2011. Catchment topography, land cover and soil maps are derived from satellite images and serve to estimate model parameters. Results of LULCC detection between 1972 and 2011 indicate a significant decrease in woodland and an increase in cropland. Woodland decreased from 42 to 14 % and from 35 to 14 % for Dinder and Rahad, respectively. Cropland increased from 14 to 47 % and from 18 to 68 % in Dinder and Rahad, respectively. The model results indicate that streamflow is affected by LULCC in both the Dinder and the Rahad rivers. The effect of LULCC on streamflow is significant during 1986 and 2011. This could be attributed to the severe drought during the mid-1980s and the recent large expansion in cropland.
Hydrology and Earth System Sciences Discussions, 2016
Hydro-climatic variability plays a pivotal role in structuring the biophysical environment of riv... more Hydro-climatic variability plays a pivotal role in structuring the biophysical environment of riverine and floodplain ecosystems. Variability is natural, but can also be enhanced by anthropogenic interventions. Alterations of hydro-climatic variables can have significant impacts on the ecohydrological functions of rivers and related ecosystems. Loss of biodiversity and degradation of ecosystems have caused increasing concern about the current situation of the Dinder and Rahad River basins (D&R), particularly the ecosystems of the Dinder National Park (DNP). However the causes are not yet fully understood. Conservation of the DNP ecosystems for direct and indirect human benefit is one of major challenges facing the country. This paper examines the long-term variations of streamflow, rainfall and temperature over the D&R and its implications on DNP ecosystems. Statistical tests of Mann-Kendall (MK) and Pettitt were used. The analysis was carried out for twelve precipitation, one temperature, and two streamflow gauging stations over different time periods. Streamflow characteristics of magnitude, duration, timing, frequency and rate of change in flow that likely impact the ecological functions of the ecosystem of the DNP, were analysed using the Indicators of Hydrologic Alterations (IHA). The MK test showed statistically significant increasing trends of temperature. The mean annual and monthly mean precipitation showed no significant change. Streamflow of the Rahad River showed a significant increasing trend in annual and monthly means at Al-Hawata station, while no significant trend in Dinder River flows at Al-Gewisi station could be observed. However, the Dinder river showed significant decreasing trend in maximum annual and monthly mean and maximum flow during August (month of high flow), and increasing trend during November (month of low flow). The IHA analysis indicated that the Rahad River flow was coupled with significant upward alterations in some of the hydrological indicators. In contrast, the Dinder River flow was coupled with significant downward alterations. This alterations in Dinder river flow are likely affect the ecosystems in DNP negatively. Alterations in magnitude and duration of the annual flood peaks
Hydrology and Earth System Sciences Discussions, 2016
Wetlands are important reservoirs of water, carbon and biodiversity. They are typical landscapes ... more Wetlands are important reservoirs of water, carbon and biodiversity. They are typical landscapes of lowland regions that have high potential for water retention. However, the hydrology of these wetlands in tropical regions is often studied in isolation from the processes taking place at the catchment scale. This contribution offers a comprehensive analysis of the hydrological dynamics of two neighbouring poorly gauged tropical basins; the Kapuas basin (98,700 km<sup>2</sup>) in West Kalimantan and the Mahakam basin (77,100 km<sup>2</sup>) in East Kalimantan, Indonesia. Both basins are characterized by vast areas of inland lowlands. The hydro-climatological data described herein were obtained during fieldwork campaigns carried out in the Kapuas over the period 2013–2015 and in the Mahakam over the period 2008–2010. Additionally, we used the Tropical Rainfall Measuring Mission (TRMM) rainfall estimates over the period 1998–2015 f...
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Papers by khalid hassaballah