Increasing Effectiveness of The Urban Artificial Reservoir Trough Cross Section Improvement

Situ Ciledug is an artificial reservoir located at Tangerang Selatan, Indonesia. In 1950 known as one of the largest lakes with total area of 32.806 hectares. As time goes by, due to the construction of housing and land use around the area, the catcahment area was reduced about 19.3 hectares in 2013 and by the end of 2020 the surface area was become 16.2 hectares. Urbanization is the main factor that makes the area of Situ Ciledug’s narrower. The second impact was flooding, as a result, the flood inundates the cities around the reservoir. This study aims to increase the storage capacities by normalizing the reservoir using SWMM 5.1 software. Hydrological analysis was carried out in the first stage to find the maximum rainfall using a 100-year return period. Then result intensity of rainfall used to analyze the hyetograph as input for rainfall data in SWMM 5.1. The modeling uses a maximum of rainfall about 107 mm with a reservoir depth of 1.3 meters. The large inflow that enters the reservoir is 87.504 m3/second aand the volume is 30.145 m3/second. Therefore, it is necessary to normalize the reservoir by increasing the depth of the reservoir by 0.7 meters. Normalization is carried out to accommodate flood discharge as a solution to flood mitigation due to the overflow.

Effects of Seasonal Thermal Stratification on Nitrogen Transformation and Diffusion at the Sediment-Water Interface in a Deep Canyon Artificial Reservoir of Wujiang River Basin

Watershed-scale nitrogen pollution in aquatic systems has become a worldwide concern due to its continuous impact on water quality deterioration, while the knowledge of key influencing factors dominating nitrogen transportation and transformation at the sediment-water interface (SWI) remains limited, especially in impounded rivers with an artificial reservoir. Hence, for a better understanding of the effects of thermal stratification on nitrogen transformation, we investigated the nitrogen species and isotopes in the sediment of a deep reservoir in Southwest China. Our results confirmed a significant difference in nitrogen species and isotopic composition in sediment between those in the thermal stratification period and non-thermal stratification period and indicated that the sediment biogeochemical process and transportation were clearly linked to the variations in water temperature and dissolved oxygen dominated by the process of thermal stratification. Significant seasonal differences in NH4+-N and NO3−-N in pore water of the upper layer (0–19 cm) revealed that nitrification exhausted NH4+ in the non-stratified period (NSP), and a potential low mineralization rate appeared when compared with those in the stratified period (SP). Seasonal differences in nitrogen species and isotope fractionation of δ15N-PON (about 2.3‰ in SP) in the upper layer sediment indicated a higher anaerobic mineralization rate of organic matter in SP than that in NSP. The diffusion fluxes of NH4+-N at SWI were 9.48 and 15.66 mg·m−2·d−1 in NSP and SP, respectively, and annual NH4+-N diffusion accounted for 21.8% of total storage in the reservoir. This study demonstrated that the nitrogen cycling processes, especially nitrification, denitrification, and mineralization, have been largely altered along with the changes in dissolved oxygen and that the diffusion of nitrogen species varied with the presence of the oxygen. The results contribute to the future study of watershed nitrogen budget evaluation and suggest that the endogenous nitrogen released from the sediment-water interface should be emphasized when aiming to fulfil water management policies in deep reservoirs.

Assessment of the state of Lake Skurcha (Republic of Abkhazia) by phytoplankton indicators (according to data for 2011, 2015)

Lake Skurcha is an artificial reservoir that was formed on the site of a quarry for the extraction of sand and gravel mixture and has a hydrological connection with the Black Sea, located in the village of Adzyubzha, Ochamchyrsky district of the Republic of Abkhazia. During the study period (2011, 2015), 53 algae taxa from 8 departments were identified. Diatoms formed 49% of the total species composition. In the interannual aspect, there is a decrease in the trophic status and an increase in water quality.

Evaluation of Artificial Reservoir Management in Sleman Regency, Yogyakarta Special Region

The Indonesian government has promoted reservoir (embung) development programs throughout Indonesia. This program is primarily designed at supporting agricultural irrigation, especially in the dry season. However, in its implementation, there are often many obstacles both in technical and management, causing the main purpose of the reservoir construction cannot be achieved optimally. Therefore, this study aims to evaluate the condition of the reservoir located in Sleman Regency, Yogyakarta Special Region, in terms of physical, institutional, and management constraints. The study was conducted through a direct survey of 9 reservoirs and interviews with managers and residents around the reservoir. The results showed that two reservoirs have small damage in the reservoir building, three reservoirs do not yet have managers, and three reservoirs have not functioned following the purpose of reservoirs development. The obstacle often found in managing reservoirs is the unclear structure for the management of the reservoir, and the existing management is not effectively working. Therefore, the regulation of using reservoir water is not available. It is necessary to have a management organization involving the community and village government where the reservoir is located and also community beneficiaries of agricultural irrigation to guarantee its function and sustainability.

The Reuse of Sediments Dredged from Artificial Reservoirs for Beach Nourishment: Technical and Economic Feasibility

Sedimentation has significant impacts on the useful capacity of an artificial reservoir, a resource to preserve. Interventions of dredging are therefore often unavoidable, even because decommissioning of dams is often impossible in many contexts and entails high costs. Dredging generates an undesired accumulation of materials that represent an environmental cost, but that could be used as intermediate products in other processes, such as beach nourishment. The study develops a method for the evaluation of the feasibility of an investment aimed at coastal nourishment with sediments dredged from artificial reservoirs. The method considers the set of technical conditions that make such use possible. The presence of economies of scope, with environmental diseconomies utilized as joint product, modifies the evaluation approach. The results of the approach show a possible environmental and economic sustainability of the proposed investment even in the presence of highly unfavorable scenarios. The study applies the feasibility appraisal to the case of the Guardialfiera reservoir in Molise, Italy.

Ethiopia-Egypt dam disputes may de-escalate

Significance The nearly completed mega-dam has been a source of immense friction between Egypt, Ethiopia and Sudan, but recent developments could create space to de-escalate. Impacts Progress on the dam offers much-needed respite to embattled Ethiopian Prime Minister Abiy Ahmed amid a serious domestic political crisis. Heavy rains have allayed fears of an immediate impact on downstream water supply, which will ease pressure on Egypt’s government. As the dam fills, issues will arise regarding the fates of the thousands of people the artificial reservoir will displace.

Performance Analysis of Single-Well Enhanced Geothermal System for Building Heating

Deep borehole heat exchanger (DBHE) technology does not depend on the existence of hot water reservoir and can be used in various regions. However, the heat extraction from DBHE can hardly be improved due to poor thermal conductivity of rocks. Here, a single-well enhanced geothermal system (SWEGS) is proposed, which has a larger heat-exchange area of artificial reservoir created by fracturing hydrothermal technology. We find that, due to heat convection between rocks and fluid, the extracted thermal output for SWEGS is 4772.73 kW, which is 10.64 times of that of DBHE. By changing the injection water temperature, volume flow rate, and artificial reservoir volume, it is easy to adjust the extracted thermal output to meet the requirement of building thermal loads varying with outdoor air temperature. Understanding these will enable us to better apply SWEGS technology and solve the fog and haze problem easily and efficiently.

Ghana

The Republic of Ghana is a country located on the west coast of Africa on the Gulf of Guinea, bordering the North Atlantic Ocean, Burkina Faso, Ivory Coast, and Togo. Ghana has a total area of 238,535 square kilometres (km), a coastline of 539 km in length, and a population of 29.6 million. Ghana is home to Lake Volta, the largest artificial reservoir in the world in terms of surface area, situated approximately 200 km from Ghana’s border with Burkina Faso.