Your search found 4 records
1 Bhatt, Yogesh; Bossio, Deborah; Enfors, E.; Gordon, L.; Kongo, V.; Kosgei, J. R.; Makurira, H.; Masuki, K.; Mul, M.; Tumbo, S. D. 2006. Smallholder system innovations in integrated watershed management (SSI): strategies of water for food and environmental security in drought-prone tropical and subtropical agro-ecosystems. Colombo, Sri Lanka: International Water Management Institute (IWMI). 59p. (IWMI Working Paper 109; SSI Working Paper 1) [doi: https://doi.org/10.3910/2009.294]
Watershed management ; Water resources ; Agroecosystems ; Social aspects ; Environmental effects ; Catchment areas ; River basins ; Hydrology ; Models ; Water productivity ; Water balance ; Water harvesting ; Crop production ; Food production ; Farming systems ; Smallholders ; Research projects / Africa South of Sahara / South Africa / Tanzania / Thukela River Basin / Pangani River Basin
(Location: IWMI-HQ Call no: IWMI 631.7 G100 BHA Record No: H039095)
(684KB)
2 Gonzalez, J. M.; Matrosov, E. S.; Obuobie, E.; Mul, M.; Pettinotti, L.; Gebrechorkos, S. H.; Sheffield, J.; Bottacin-Busolin, A.; Dalton, J.; Smith, D. Mark; Harou, J. J. 2021. Quantifying cooperation benefits for new dams in transboundary water systems without formal operating rules. Frontiers in Environmental Science, 9:596612. [doi: https://doi.org/10.3389/fenvs.2021.596612]
Dams ; International waters ; Water systems ; International cooperation ; Infrastructure ; River basins ; Reservoir operation ; Water policies ; Hydropower ; Ecosystem services ; Environmental flows ; Irrigation ; Simulation models / Ghana / Volta River Basin / Pwalugu Multipurpose Dam
(Location: IWMI HQ Call no: e-copy only Record No: H050729)
https://www.frontiersin.org/articles/10.3389/fenvs.2021.596612/pdf
https://vlibrary.iwmi.org/pdf/H050729.pdf
https://vlibrary.iwmi.org/pdf/H050729.pdf
(9.16 MB) (9.16 MB)
New dams impact downstream ecosystems and water infrastructure; without cooperative and adaptive management, negative impacts can manifest. In large complex transboundary river basins without well codified operating rules and extensive historical data, it can be difficult to assess the benefits of cooperating, in particular in relation to new dams. This constitutes a barrier to harmonious development of river basins and could contribute to water conflict. This study proposes a generalised framework to assess the benefits of cooperation on the management of new dams in water resource systems that do not have formal sharing arrangements. Benefits are estimated via multi-criteria comparison of historical reservoir operations (usually relatively uncooperative) vs. adopting new cooperative rules which would achieve the best results for riparian countries as evaluated by a water resources simulator and its performance metrics. The approach is applied to the Pwalugu Multipurpose Dam (PMD), which is being built in Ghana in the Volta river basin. The PMD could impact downstream ecosystems and infrastructure in Ghana and could itself be impacted by how the existing upstream Bagre Dam is managed in Burkina Faso. Results show that with cooperation Ghana and Burkina Faso could both increase energy production although some ecosystem services loss would need to be mitigated. The study confirms that cooperative rules achieve higher overall benefits compared to seeking benefits only for individual dams or countries.
3 Owusu, A.; Salazar, J. Z.; Mul, M.; van der Zaag, P.; Slinger, J. 2023. Quantifying the trade-offs in re-operating dams for the environment in the Lower Volta River. Hydrology and Earth System Sciences, 27(10):2001-2017. [doi: https://doi.org/10.5194/hess-27-2001-2023]
Dams ; River basins ; Ecosystem services ; Environmental flows ; Irrigation ; Hydropower ; Reservoirs ; Flood control ; Climate change ; Climate prediction ; Water users ; Communities / Ghana / Lower Volta River Basin / Akosombo Dam / Kpong Dam
(Location: IWMI HQ Call no: e-copy only Record No: H052038)
https://hess.copernicus.org/articles/27/2001/2023/hess-27-2001-2023.pdf
https://vlibrary.iwmi.org/pdf/H052038.pdf
https://vlibrary.iwmi.org/pdf/H052038.pdf
(2.98 MB) (2.98 MB)
The construction of the Akosombo and Kpong dams in the Lower Volta River basin in Ghana changed the downstream riverine ecosystem and affected the lives of downstream communities, particularly those who lost their traditional livelihoods. In contrast to the costs borne by those in the vicinity of the river, Ghana has enjoyed vast economic benefits from the affordable hydropower, irrigation schemes and lake tourism that developed after construction of the dams. Herein lies the challenge; there exists a trade-off between water for river ecosystems and related services on the one hand and anthropogenic water demands such as hydropower or irrigation on the other. In this study, an Evolutionary Multi-Objective Direct Policy Search (EMODPS) is used to explore the multi-sectoral trade-offs that exist in the Lower Volta River basin. Three environmental flows, previously determined for the Lower Volta, are incorporated separately as environmental objectives. The results highlight the dominance of hydropower production in the Lower Volta but show that there is room for providing environmental flows under current climatic and water use conditions if the firm energy requirement from Akosombo Dam reduces by 12 % to 38 % depending on the environmental flow regime that is implemented. There is uncertainty in climate change effects on runoff in this region; however multiple scenarios are investigated. It is found that climate change leading to increased annual inflows to the Akosombo Dam reduces the trade-off between hydropower and the environment as this scenario makes more water available for users. Furthermore, climate change resulting in decreased annual inflows provides the opportunity to strategically provide dry-season environmental flows, that is, reduce flows sufficiently to meet low flow requirements for key ecosystem services such as the clam fishery. This study not only highlights the challenges in balancing anthropogenic water demands and environmental considerations in managing existing dams but also identifies opportunities for compromise in the Lower Volta River.
4 Seijger, C.; Chukalla, A.; Bremer, K.; Borghuis, G.; Christoforidou, M.; Mul, M.; Hellegers, P.; van Halsema, G. 2023. Agronomic analysis of WaPOR applications: confirming conservative biomass water productivity in inherent and climatological variance of WaPOR data outputs. Agricultural Systems, 211:103712. (Online first) [doi: https://doi.org/10.1016/j.agsy.2023.103712]
Water productivity ; Climatic data ; Biomass ; Agronomic characters ; Analysis ; Remote sensing ; Evapotranspiration ; Climate variability ; Agronomy / Ethiopia
(Location: IWMI HQ Call no: e-copy only Record No: H052209)
(4.96 MB)
CONTEXT: Improvements in agricultural water productivity with constrained water resources are often regarded a prerequisite to meet food demands of a growing world population. The WaPOR data portal was launched to monitor biomass, evapotranspiration and biomass water productivity in Africa and the Near East using remote sensing technologies. The WaPOR database shows spatial pixel variation in biomass, suggesting scope to improve water productivity at field level.
OBJECTIVE: The aim of this paper is to assess with regression analyses for different spatial and temporal scales whether spatial variability in biomass and evapotranspiration as revealed by WaPOR can be attributed to human influenceable factors, variations in local climate, or methodologically inherent inacuracies of the WaPOR data.
METHODS: Variation in biomass and evapotranspiration data was assessed through agronomic linear regression analyses, for two large-scale irrigated sugarcane estates in Ethiopia (Wonji) and Mozambique (Xinavane).
RESULTS AND CONCLUSIONS: In these cases 82–94% of the variation in biomass and evapotranspiration is attributed to crop photosynthetic efficiency (very large influence), local climate (large influence) and irrigation technology (small influence). The remaining unexplained spatial variability is small (6–18%) and falls within an error range of +/- 9%. In conclusion, WaPOR performed very well by neatly reproducing the conservative relationship between biomass and evapotranspiration, which also means there is very limited scope to improve biomass water productivity through WaPOR monitoring. Further research is recommended on the magnitude of WaPOR accuracy and other sources that explain variations in biomass and evapotranspiration.
SIGNIFCANCE: Applicability of the WaPOR database to monitor biomass water productivity was assessed. Spatial variability in biomass and evapotranspiration data largely stemmed from photosynthesis and local climate, factors farmers and water managers can hardly influence.
OBJECTIVE: The aim of this paper is to assess with regression analyses for different spatial and temporal scales whether spatial variability in biomass and evapotranspiration as revealed by WaPOR can be attributed to human influenceable factors, variations in local climate, or methodologically inherent inacuracies of the WaPOR data.
METHODS: Variation in biomass and evapotranspiration data was assessed through agronomic linear regression analyses, for two large-scale irrigated sugarcane estates in Ethiopia (Wonji) and Mozambique (Xinavane).
RESULTS AND CONCLUSIONS: In these cases 82–94% of the variation in biomass and evapotranspiration is attributed to crop photosynthetic efficiency (very large influence), local climate (large influence) and irrigation technology (small influence). The remaining unexplained spatial variability is small (6–18%) and falls within an error range of +/- 9%. In conclusion, WaPOR performed very well by neatly reproducing the conservative relationship between biomass and evapotranspiration, which also means there is very limited scope to improve biomass water productivity through WaPOR monitoring. Further research is recommended on the magnitude of WaPOR accuracy and other sources that explain variations in biomass and evapotranspiration.
SIGNIFCANCE: Applicability of the WaPOR database to monitor biomass water productivity was assessed. Spatial variability in biomass and evapotranspiration data largely stemmed from photosynthesis and local climate, factors farmers and water managers can hardly influence.
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