• Energy Research

Sustainability of rainwater harvesting in enhancing water productivity in various biophysical and socioeconomic conditions of SSA is a key in large scale livelihood improvement. A study was undertaken in Makanya catchment of rural Tanzania to assess sustainability of storage type of rainwater harvesting systems including microdam, dug out pond, sub-surface runoff harvesting tank and rooftop rainwater harvesting system. The increasing population in upstream areas of the catchment has forced use of RWH systems for streams and river water abstraction. The agricultural intensification in hillslopes has affected the water availability for downstream uses. Rainfall variability, runoff quality and quantity, local skills and investment capacity, labour availability and institutional support influence sustainability of rainwater harvesting systems.

Sustainability of rainwater harvesting in enhancing water productivity in various biophysical and socioeconomic conditions of SSA is a key in large scale livelihood improvement. A study was undertaken in Makanya catchment of rural Tanzania to assess sustainability of storage type of rainwater harvesting systems including microdam, dug out pond, sub-surface runoff harvesting tank and rooftop rainwater harvesting system. The increasing population in upstream areas of the catchment has forced use of RWH systems for streams and river water abstraction. The agricultural intensification in hillslopes has affected the water availability for downstream uses. Rainfall variability, runoff quality and quantity, local skills and investment capacity, labour availability and institutional support influence sustainability of rainwater harvesting systems.

This study investigated the dependence of three riparian communities on ecosystem services in northern Ghana. Participatory mapping and ranking exercises in gender-segregated groups were used to elicit information on the communities’ livelihoods. The most important ecosystem-based activities (EBA) are farming, fishing, livestock watering and grazing, collection of wild fruits and vegetables, and provision of water for domestic use. The major EBA are dependent on the seasonal flows of the White Volta River, which are under pressure due to climatic and other anthropogenic changes. For example, observed delays in the start of the rainy season are affecting rainfed agricultural activities on the floodplains. Delayed planting on the floodplains results in damage to, or loss of, crops as floods arrive before the harvest. Moreover, the Bagré Dam in Burkina Faso, built upstream of the communities, has impacted the natural river flow. The planned Pwalugu Dam may, depending on the final operations, support or affect EBA. We, therefore, recommend that operations of the Pwalugu Dam should take into consideration the flow requirements of EBA downstream of the dam.

This study investigated the dependence of three riparian communities on ecosystem services in northern Ghana. Participatory mapping and ranking exercises in gender-segregated groups were used to elicit information on the communities’ livelihoods. The most important ecosystem-based activities (EBA) are farming, fishing, livestock watering and grazing, collection of wild fruits and vegetables, and provision of water for domestic use. The major EBA are dependent on the seasonal flows of the White Volta River, which are under pressure due to climatic and other anthropogenic changes. For example, observed delays in the start of the rainy season are affecting rainfed agricultural activities on the floodplains. Delayed planting on the floodplains results in damage to, or loss of, crops as floods arrive before the harvest. Moreover, the Bagré Dam in Burkina Faso, built upstream of the communities, has impacted the natural river flow. The planned Pwalugu Dam may, depending on the final operations, support or affect EBA. We, therefore, recommend that operations of the Pwalugu Dam should take into consideration the flow requirements of EBA downstream of the dam.

Assessing drought impacts is necessary for pursuing sustainable development goals relevant to food security and land degradation. Data availability is a major restriction and remote sensing has been promoted for this purpose. Version 3 of WaPOR has been released in 2023, which provides global coverage of remote sensing-derived water productivity indicators and could allow improved analysis of drought impacts, but validation is still needed. This study explores the utility of remote sensing-derived productivity data from WaPOR as a proxy indicator for agricultural drought impacts. The analysis utilized (1) production surveys, (2) meteorological measurements for drought analysis, and (3) remote sensing-derived gross and net biomass water productivities (GBWP & NBWP) and total biomass production (TBP). All layers were analyzed against the Standardized Precipitation and Standardized Precipitation Evapotranspiration Indices (SPI and SPEI) over drought-vulnerable locations in Irbid and Madaba governorates in Jordan. Strong and significant correlations (R2 0.5-0.8, P < 0.05) were obtained between drought intensities and GBWP and NBWP layers, particularly in the May-Sep periods. These correlations were higher than previously tested remotely sensed indicators for agricultural drought impacts. Water productivity and biomass production averages were lower during drier periods and higher during wet periods, but pairwise testing did not reveal significant differences. There is sufficient evidence that WaPOR data demonstrates behavior that reflects agricultural response to drought, and further assessment in other agroclimatic zones is recommended. This could potentially allow for enhanced evaluation of management strategies, decision support, and policy recommendations for drought mitigation.

Assessing drought impacts is necessary for pursuing sustainable development goals relevant to food security and land degradation. Data availability is a major restriction and remote sensing has been promoted for this purpose. Version 3 of WaPOR has been released in 2023, which provides global coverage of remote sensing-derived water productivity indicators and could allow improved analysis of drought impacts, but validation is still needed. This study explores the utility of remote sensing-derived productivity data from WaPOR as a proxy indicator for agricultural drought impacts. The analysis utilized (1) production surveys, (2) meteorological measurements for drought analysis, and (3) remote sensing-derived gross and net biomass water productivities (GBWP & NBWP) and total biomass production (TBP). All layers were analyzed against the Standardized Precipitation and Standardized Precipitation Evapotranspiration Indices (SPI and SPEI) over drought-vulnerable locations in Irbid and Madaba governorates in Jordan. Strong and significant correlations (R2 0.5-0.8, P < 0.05) were obtained between drought intensities and GBWP and NBWP layers, particularly in the May-Sep periods. These correlations were higher than previously tested remotely sensed indicators for agricultural drought impacts. Water productivity and biomass production averages were lower during drier periods and higher during wet periods, but pairwise testing did not reveal significant differences. There is sufficient evidence that WaPOR data demonstrates behavior that reflects agricultural response to drought, and further assessment in other agroclimatic zones is recommended. This could potentially allow for enhanced evaluation of management strategies, decision support, and policy recommendations for drought mitigation.