Basin Resources Research Articles

The combination of Multi-Criteria Decision-Making (MCDM) and morphometric parameters for prioritizing the erodibility of sub-watersheds in the Ouljet Es Soltane basin (North of Morocco)

Preserving water and soil resources ranks among the top priorities outlined in the national water strategy. Indeed, the integrated management of water resources in vulnerable territories, particularly in Morocco, requires a deep knowledge of the hydrological functioning and use of water resources in these regions. The diverse hydroclimatic and morphological features within the Ouljet Es Soltane watershed, which is a sub-basin of the extensive Oued Sebou watershed, present significant challenges in managing its water and soil resources. Identifying areas susceptible to soil erosion is crucial for implementing preventive measures in the Ouljet Es Soltane basin and ensuring its sustainable development. Morphometric analysis plays an important role in the effective management and sustainable utilization of the basin's resources. This study used four MCDM models, including the CF (Compound Factor), VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje), TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), and SAW (Simple Additive Weighing), to prioritize 20 sub-watersheds of the Ouljet Es Soltane watershed.Based on the sub-watershed prioritization results obtained from the VIKOR, TOPSIS, and SAW models, sub-watershed 16 achieved scores of 0, 0.59, and 0.8, respectively, positioning it as the first rank. These findings highlight that sub-watershed 16 exhibits a high susceptibility to erosion and is classified as one of the most vulnerable areas in terms of erosion risk.Based on the results obtained from the VIKOR, TOPSIS, and SAW models, the susceptibility of the sub-watersheds to erosion can be classified into four categories: low, moderate, high, and very high. On the other hand, the CF model only has two categories: low and moderate susceptibility. Overall, the findings suggest that morphometric parameters are highly effective in identifying areas at risk of erosion. Furthermore, the VIKOR, TOPSIS, and SAW methods exhibit greater predictive accuracy compared to the CF model. The comparison of these models involved the use of Spearman correlation coefficient test (SCCT).The findings of this study can provide valuable insights for making informed decisions in developing an effective framework for soil erosion control strategies.

Evaluating the effectiveness of principles used for sharing resources of the Lower Ankobra Basin in the Western Region, Ghana

AbstractThis paper evaluates the effectiveness of principles used for sharing resources of the Lower Ankobra River Basin found in the Western Region of Ghana. The purpose is to find out whether the institutions in charge of the management of the Lower Ankobra Basin are using principles prescribed by the United Nations Development Programme and the Sustainable Human Development (1997) for equitable sharing of the resources of the Lower Ankobra River Basin. The study adopted the descriptive research design. By means of in‐depth and semi‐structured interview guides, information was solicited from 268 respondents who played diverse roles in the conservation of the basin's resources. The paper found that management institutions fail to follow the right principles, such as equity, accountability, and efficiency, when distributing resources in the basin. The final results showed evidence of misallocation and uneven distribution of the basin's resources. It is recommended that the management institutions should periodically provide accurate, accessible, and comprehensible information on how resources have been utilized, by using community bulletin boards and social gatherings on behalf of users of the basin. In addition, to promote equity, the Government of Ghana must first compensate and reclaim all the lands in the basin from individuals whose activities impact negatively on its resources and hand them over to the Water Resources Commission for redistribution to more efficient areas of production based on the powers enshrined in Section 12 and 13 of the Water Management Act, Act 522, of Ghana.

How much inundation occurs in the Amazon River basin?

The Amazon River basin harbors some of the world's largest wetland complexes, which are of major importance for biodiversity, the water cycle and climate, and human activities. Accurate estimates of inundation extent and its variations across spatial and temporal scales are therefore fundamental to understand and manage the basin's resources. More than fifty inundation estimates have been generated for this region, yet major differences exist among the datasets, and a comprehensive assessment of them is lacking. Here we present an intercomparison of 29 inundation datasets for the Amazon basin, based on remote sensing only, hydrological modeling, or multi-source datasets, with 18 covering the lowland Amazon basin (elevation <500 m, which includes most Amazon wetlands), and 11 covering individual wetland complexes (subregional datasets). Spatial resolutions range from 12.5 m to 25 km, and temporal resolution from static to monthly, spanning up to a few decades. Overall, 31% of the lowland basin is estimated as subject to inundation by at least one dataset. The long-term maximum inundated area across the lowland basin is estimated at 599,700 ± 81,800 km2 if considering the three higher quality SAR-based datasets, and 490,300 ± 204,800 km2 if considering all 18 datasets. However, even the highest resolution SAR-based dataset underestimates the maximum values for individual wetland complexes, suggesting a basin-scale underestimation of ~10%. The minimum inundation extent shows greater disagreements among datasets than the maximum extent: 139,300 ± 127,800 km2 for SAR-based ones and 112,392 ± 79,300 km2 for all datasets. Discrepancies arise from differences among sensors, time periods, dates of acquisition, spatial resolution, and data processing algorithms. The median total area subject to inundation in medium to large river floodplains (drainage area > 1000 km2) is 323,700 km2. The highest spatial agreement is observed for floodplains dominated by open water such as along the lower Amazon River, whereas intermediate agreement is found along major vegetated floodplains fringing larger rivers (e.g., Amazon mainstem floodplain). Especially large disagreements exist among estimates for interfluvial wetlands (Llanos de Moxos, Pacaya-Samiria, Negro, Roraima), where inundation tends to be shallower and more variable in time. Our data intercomparison helps identify the current major knowledge gaps regarding inundation mapping in the Amazon and their implications for multiple applications. In the context of forthcoming hydrology-oriented satellite missions, we make recommendations for future developments of inundation estimates in the Amazon and present a WebGIS application (https://amazon-inundation.herokuapp.com/) we developed to provide user-friendly visualization and data acquisition of current Amazon inundation datasets.

Laguna de Bay: Institutional development and change for lake basin management

AbstractLaguna de Bay is a large, shallow lake located near Manila, Philippines. The lake is drained by the Pasig River, which flows to Manila Bay. It periodically reverses direction, bringing saline water into this predominately freshwater body. The lake has historically been of great importance to locals who depend on it for fish and related livelihoods. Recently, it also has been considered a source of potable water for the Manila region. The intense land use in the watershed has caused enhanced siltation, and the lake has also been plagued by overfishing, intense aquaculture and water pollution from industrial and domestic sources. This paper overviews these issues and examines the role of the Laguna Lake Development Authority in developing and conserving the lake basin's resources. Two programmes related to fisheries development and an environmental user‐fee programme to control water pollution are critiqued. Lessons learned from the nearly 40 years of experience managing this tropical lake also are presented.

The planning and management of African river and lake basin development and conservation

The success of river and lake basin development and management is rooted in the knowledge of its resources, both physical and human. Within the framework of an integrated basin plan, each economic sector depends on the adequacy of such data for its individual development. The management and conservation of the basin itself in turn depends on knowing the requirements of those sectors and their probable impact on each other and on the status of the basin's resources, its ecology and environment. The development of African river basin resources is subject to various constraints, some for physical and climatic reasons, others tied to socio‐cultural characteristics and the priorities of national economies. These are reflected in financial, manpower and institutional limitations, problems of finding technologies suited to specific local conditions and concern for human health. The scale and complexity of river basin development make it difficult to predict precise outcomes of planned proposals, but a progressive approach which links long‐term activities with achievable, shorter term production projects offers prospects for ultimate success.

WATER RESOURCES DEVELOPMENT IN THE MULLICA RIVER BASIN1

ABSTRACT: The potential withdrawal of water from the Mullica River‐Great Bay Estuary is southern New Jersey prompted a joint study by biologists and engineers to determine the maximum supply of water that could be diverted from the basin without causing undue environmental impacts. The effect of removal of water from the basin over long periods of time was simulated by review of records of a severe drought. Based on analysis of streamflows and salinities during these drought conditions, minimum mean monthly streamflows were determined corresponding to the maximum salinities tolerable by the fish and shellfish communities, important sources of revenue and recreation in the region. A physically optimized, chance constrained linear programming model was developed for the conjunctive use of ground and surface waters. Adjusting water withdrawal from streamflow and groundwater sources according to physical and seasonal criteria would permit maximum use of the basin's resources, with no additional burden on the ecology of the estuary.