Volume 2, Issue 1, 2018
Aquademia: Water, Environment and Technology, 2018, 2(1), 01, https://doi.org/10.20897/awet/86715
ABSTRACT: Bridge pier scouring is an important issue for safety evaluation of bridges. The existing equations for bridge pier scour prediction are mostly deterministic in nature, which do not incorporate the uncertainties in various parameters of scouring. A methodology for reliability analysis of bridge pier against scour in cohesive sediments incorporating the uncertainties of the model and input parameters are presented herein using efficient spreadsheet algorithm for first order reliability method (FORM). The influence of uncertainties, the nature of probability distribution and correlation of basic input parameters on failure probability and reliability index has been studied and described briefly herein. A sensitivity analysis was also carried out to obtain the effect of the individual random variables on the reliability of pier scour. To achieve the desired safety level in the design of pier foundation, the reliability-based safety factor is proposed.
Hydrological Studies for the Assessment of Run-of-River Hydropower Potential and Generation over the Wouri-Nkam River using GIS and Remote Sensing Techniques
Aquademia: Water, Environment and Technology, 2018, 2(1), 02, https://doi.org/10.20897/awet/86712
ABSTRACT: Cameroon has several renewable energy sources, including solar, wind, and hydropower. With the liberalisation of the hydroelectric energy sector in Cameroon, rural communities are yet to feel the impact. Small Hydropower projects should have been developed to curb the acute shortage of electricity within these localities and beyond. This is not the case yet. It is in this respect that this study is carried out: to assess the hydropower potential of the Nkam Division and environs and propose sites for the development of hydroelectricity. Geographical Information System, Remote Sensing techniques, and hydrological models (HEC-HMS) were used. Grid analyses were carried out on the Digital Elevation Models (DEMs) using the Watershed Modelling System software to delineate the catchment basin with the sub-basins. Digital Soil and Land use data were obtained from the Harmonised World Soil Data and World Land use Data respectively, which together were used to calculate the Composite Curve Number in QGIS for the various sub-basins. The curve numbers together with other hydrological parameters were used to develop a HEC-HMS deterministic hydrologic model for the catchment basin. The resulting model was calibrated and validated in HEC-HMS, using precipitation data obtained from the localised Yabassi weather station and discharge values from a gauging station at Yabassi. The calibrated peak discharge produced an absolute error of 3.4% and a Nash-Sutcliffe value of 0.301. The hypsometric curve presents a hilly landscape, with 40% of the surface area having elevations of between 10 to 30 m, favouring the development of small scale hydro systems. The RETScreen software was used for the hydro-energy analyses and the estimated potential power, for a hydraulic head of 20 m, stood at 13,813 kW. The values of the Benefit-Cost Ratio value of 1.3 and the Net Present Value greater than zero show that the project is very practical and profitable. It follows that Small and Medium Run-of-River Hydropower Plants can be developed from the Wouri–Nkam Reach, the significant reach in the river network of the Catchment Basin, with an estimated compensation flow of 133.17m3/s for ecological continuity. The project will reduce about 27,064.8 tons of CO2 from the atmosphere.
Aquademia: Water, Environment and Technology, 2018, 2(1), 03, https://doi.org/10.20897/awet/86714
ABSTRACT: India is a country of villages with 68.84% of the total population living in rural areas. The villagers are lagging in their developments due to the scarcity of water. Hence in this study, it was decided to find out the technique of water conservation which will sustain in rural areas and to compile the results by applying the model which will work for this. Considering the topographical features of a small plot of area two hectares of Kaneri watershed situated in Kolhapur District, Maharashtra, the structures for water conservation had been implemented in it in June 2011. The structures included gully plugs on existing water stream followed by the farm pond at its end along with farm terraces and continuous contour trenches surrounding the water stream. The practical evidence proved the positive impact of water conservation structures on water conservation and groundwater recharge. For assessing this impact technically for ungauged Kaneri watershed, SWAT (Soil and Water Assessment Tool) Model was used in the study and both the results were compiled. From the model results, the sediment yield and water yield showed expected impact on the watershed. Thus, the SWAT model proved to be an effective tool in assessing the impact of changes in land management on runoff and sediment yield.