Search Results (3)

Owing to their capacity to conserve water and regulate streamflow, small reservoirs are useful for agriculture, domestic water supply, energy production, industry, flood control, recreation, fisheries, and ecosystem conservation. The presence of these small reservoirs often affects the natural water pathways, but the use of a hydrological model such as the Soil and Water Assessment Tool (SWAT) can help to better apprehend these effects at the watershed scale. Indeed, the SWAT model allows modelers to represent and operate reservoirs by inputting the related parameters while setting the model. However, these reservoir parameters are not automatically generated by the SWAT model algorithms. Subsequently, SWAT users are left alone and must sort out the adequate approach to separately obtain or determine the reservoir parameters. Traditionally, reservoir parameters such as the volumes and surface areas are obtained through in situ hydrographic surveys which are costly and labor demanding. To help SWAT modelers retrieve the input parameters needed for modeling small reservoirs, this paper explicitly presents a spatial analysis procedure using the case study of a small watershed reservoir. In this procedure, the digital elevation model of the watershed is transformed into a triangulated irregular network and turned into contour lines which are used to identify the reservoir surface and volume at the principal and emergency spillways. The retrieved parameters were successfully used to calibrate and validate SWAT simulations of the watershed hydrological behavior. The spatial analysis procedure reported here is a cost-effective alternative to traditional in situ hydrographic surveys and it is useful for addressing watersheds with small reservoirs. The procedure eases the inclusion of reservoirs in SWAT and reduces the risk of model overfitting. Furthermore, the procedure could be useful for developing reservoir elevation–capacity–area curves. Full article

Measurements of mass flow through a three-outlet spillway modeled after a scaled-down spillway were conducted. The inlet and channel leading up to the outlets were placed to lead the water toward the outlet at an angle. With this, measurements of the water level at three locations were recorded by magnetostrictive sensors. The volumetric flow rates for each individual outlet were recorded separately to study the differences between them. Additionally, Acoustic Doppler Velocimetry was used to measure water velocities close to the outlets. The conditions changed were the inlet volume flow rate and the flow distribution was measured at 90, 100, 110, and 200 L per second. Differences between the outlets were mostly within the error margin of the instruments used in the experiments with larger differences shown for the 200 L test. The results produced together with a CAD model of the setup can be used for verification of CFD methods. A simulation with the k-epsilon turbulence model is included and compared to earlier experiments and the new experimental results. Larger differences are seen in the new experiments. Differing inlet conditions are assumed as the principal cause for the differences seen. Full article

Check dams are applied worldwide as an effective approach for soil and water conservation. To improve the simulation accuracy of the hydrological processes in a catchment with a check-dam system, this study analyzed the applicability and accuracy of a formula for the drainage process of a perforated riser principal spillway based on observational experiments. The rainfall-runoff processes in a catchment with a check-dam system were also simulated with the recommended formulas for the drainage process of a perforated riser principal spillway. The deviations in the calculated discharge from the observed values of the experiment with the recommended formulas under normal and abnormal working conditions were within ±15% and ±5%, respectively. The hydrologic model used in this study needed only a few parameters to achieve a satisfactory simulation accuracy. The recommended formulas for the drainage process of a perforated riser principal spillway can improve the simulation accuracy of a flood peak by 7.42% and 19.58% compared with the accuracies of the technical code formula scenario and no drainage scenario, respectively. The results of this study are expected to provide a reference for flood warnings and safe operations of check-dam systems. Full article