Review of Methods of Measuring Streamflow Using Hydraulic Structures

The measurement of streamflow is very critical to hydraulic engineers and hydrologists as it provides vital information for environmental monitoring issues connected to water resources. The objective of this study is to examine various means of measuring streamflow specifically application of hydraulic structures installed across the direction of flow. Weirs are restricted to small rivers where the provision for sufficient head and constriction in the river is acceptable. Sharp-crested weir is easy to construct, and it is commonly used as a flow measuring device in an open channel. Flumes are self-cleaning due to the fact that the flow velocity through a flume is usually high. Traditionally, flume is used in measuring flow in agricultural systems, and it requires low maintenance cost. It has capacity to measure more flow rates than weir. Accurate streamflow measurement using flume is within ±2–5% while that of weir is ±2%. Generally, flumes are employed to determine discharge where weirs are not useful

Coupled 1D-2D hydrodynamic inundation model for sewer overflow: Influence of modeling parameters

AbstractThis paper presents outcome of our investigation on the influence of modeling parameters on 1D-2D hydrodynamic inundation model for sewer overflow, developed through coupling of an existing 1D sewer network model (SWMM) and 2D inundation model (BREZO). The 1D-2D hydrodynamic model was developed for the purpose of examining flood incidence due to surcharged water on overland surface. The investigation was carried out by performing sensitivity analysis on the developed model. For the sensitivity analysis, modeling parameters, such as mesh resolution Digital Elevation Model (DEM) resolution and roughness were considered. The outcome of the study shows the model is sensitive to changes in these parameters. The performance of the model is significantly influenced, by the Manning's friction value, the DEM resolution and the area of the triangular mesh. Also, changes in the aforementioned modeling parameters influence the Flood characteristics, such as the inundation extent, the flow depth and the velocity across the model domain

MODELLING THE IMPACTS OF SELECTED WATERSHED MANAGEMENT STRATEGIES ON SEDIMENT REDUCTION UPSTREAM OF SHIRORO DAM, NIGERIA

This research utilized a regulated hydrological model, Soil and Water Assessment Tool (SWAT) interfaced with Geographical Information System (GIS), in studying the effectiveness of the chosen watershed management strategies on sediment reduction upstream of Shiroro dam, Nigeria. Selected management approaches were modelled while calibration and validation of the model were achieved using observed streamflow data. Findings indicated a good correlation during calibration and validation period. Application of reforestation, vegetative filter strips and stone bunds in the watershed reduces sediment production by 27 %, 39 %, and 15 % respectively. Thus, the sediment management scenarios depicted within this research are considerably sustainable and effective

MODELLING THE IMPACTS OF SELECTED WATERSHED MANAGEMENT STRATEGIES ON SEDIMENT REDUCTION UPSTREAM OF SHIRORO DAM, NIGERIA

This research utilized a regulated hydrological model, Soil and Water Assessment Tool (SWAT) interfaced with Geographical Information System (GIS), in studying the effectiveness of the chosen watershed management strategies on sediment reduction upstream of Shiroro dam, Nigeria. Selected management approaches were modelled while calibration and validation of the model were achieved using observed streamflow data. Findings indicated a good correlation during calibration and validation period. Application of reforestation, vegetative filter strips and stone bunds in the watershed reduces sediment production by 27 %, 39 %, and 15 % respectively. Thus, the sediment management scenarios depicted within this research are considerably sustainable and effective

SWAT analysis of Ikere Gorge basin for hydrokinetic power estimation in selected rural settlements of Oke Ogun, Nigeria

The issue of power generation is the bane of rural development. Power availability will not only raise standard of living but will also enhance people livelihood. This work examines the application of soil and water Assessment Tool (SWAT) in hydrological analysis of upper catchment of Ikere Gorge Basin for hydrokinetic energy estimation. The operation of hydrokinetic turbines depends on river flow and pressure head (∆H). SWATGIS system was used to determine the hydrological parameters of the sub-basins. SWAT is a version of ArcGIS Software. The result of the analysis was used to estimate the theoretical hydrokinetic power potential of the selected basins. The total theoretical hydrokinetic energy potential of the 10 basin selected was estimated as 36.4 MW. Potential hydrokinetic energy was computed using a theoretical procedure, assuming a head of 0.3 meters and a constant weight of water at 9800 n/m³. The hydrokinetic energy potential was highest in Oshe at Onikankan (9.542 MW) and lowest in Kojuoba at Olonje (0 MW). The SWAT software was later used to create Geo-database for each catchment of Hydrologic Response Unit (HURs) of the basin under study. A spatial structured query language (SSQL) was used to perform query analysis on the potential of the sites selected for hydrokinetic energy estimation. Keywords

Cost effectiveness of sediment management strategies for mitigation of sedimentation at Jebba Hydropower reservoir, Nigeria

In this study, a calibrated hydrologic model, Soil and Water Assessment Tool (SWAT) interfaced with Geographical Information System (GIS) tool was used to study the effect of different sediment management methods in a watershed (12,992 km2) upstream of Jebba Lake, Nigeria. Sediment management strategies considered are (i) reforestation of the watershed, (ii) application of vegetative filter strip (VFS) and (iii) construction of stone bunds. Cost analysis of implementing the selected erosion control measures within the watershed was also carried out to compare the cost effectiveness of each of the management strategies. The results showed that application of VFS, reforestation, and stone bunds to critical zones of the watershed reduced the sediment yield up to 65.6%, 63.4% and 12% respectively while the financial analysis of implementing reforestation, VFS and stone bunds revealed 84.9%, 73.3% and 70.5% reduction respectively in the costs to be incurred if sediments are allowed to accumulate in the dam. From this analysis, it can be concluded that the sediment management scenarios considered in this study are cost effective and sustainable when compared with the costs incurred in tackling the effect due to reservoir sedimentation. Overall, the study showed that hydrological models such as SWAT can be used to study strategies for water resource management. In addition, it can provide policy makers the decision support tools to evaluate the cost and benefits of adopting Best Management Practices (BMPs) particularly for sediment control in erosion prone watersheds. Keywords: Cost analysis, Jebba Reservoir, Sediment management, SWAT, Watershe