Base flow

Sustainable development, use and management of groundwater resources is a challenge under the current population growth, land degradation, climate change and economic development require proper quantification of groundwater recharge. Therefore, this study anticipated the amount, spatial and temporal variability of groundwater recharge at the Bulbul River Catchment of Gilgel-Gibe River Basin (Ethiopia) using the soil mass balance method in conjunction with base-flow separation method.Theresult shows coefficient of groundwater recharge by the precipitation isestimated to be 23.07% and 25.62%from theestablished soil moisture budget model and the base-flow model respectively. Even though, change in groundwater storage in the area is positive, the river flow demonstrated a seasonal shift from summer to autumn. This change may substantially alter seasonal water retention capacity in the river catchment and irrigation development in the floodplain following the embankment. Hence, supplementary irrigation water application at the time of water shortage in the area is highly recommended.

Abstract. Hydrograph recession constants are required in rainfall-runoff models, base flow augmen-tation studies, geohydrologic investigations and in regional low-flow studies. The recession portion of a streamflow hydrograph is shown to be either an autoregressive process or an integrated moving average process, depending upon the structure of the assumed model errors. Six different estimators of the base flow recession constant are derived and tested using thousands of hydrograph recessions available at twenty-three sites in Massachusetts, U.S. When hydrograph recessions are treated as an autoregressive process, unconditional least squares or maximum likelihood estimators of the base-flow recession constant are shown to exhibit significant downward bias due to the short lengths of hydrograph recessions. The precision of estimates of hydrograph recession constants is shown to depend heavily upon assumptions regarding the structure of the model errors. In general, regression procedu...

Extraction of watershed parameters using Remote Sensing and Geographical Information System (GIS) and use of mathematical models is the current trend for hydrologic evaluation of watersheds. The Soil and Water Assessment Tool (SWAT) having an interface with QGIS is adopted in the present study for the determination of various outputs, viz. Surface runoff, Base flow, Percolation, Potential evapotranspiration and Sediment load in Vishwamitri river watershed in Vadodara, Gujarat, India. Various data types required as input for the study comprises of Digital Elevation Models (DEM), Landuse/Landcover maps, Soil maps and Climate data. The Stream considered lies between 22° 13' to 22° 21' of north latitude and 73° 12' to 73° 13' of east longitude. Providing require inputs, SWAT model was simulated for 2003 to 2014. Analysis reveals that maximum rainfall was obtained in 2005 and minimum rainfall is obtained in 2009. In 2005, it is found out that the Precipitation is maximum, and the corresponding surface runoff in sub-basins 3 and 5 are having highest values of 767.04mm and 747.87mm respectively. Similarly, baseflow in sub-basin 3 & 5 are having lowest values of 298.20mm and 316.40mm respectively. The percolation in sub-basin 3 & 5 are also having the lowest values of 363.10mm and 381.70mm respectively. The Surface runoff, Base flow and Percolation were found out to be around 48%, 20% and 32% of the precipitation occurred in 2005, while amongst the average precipitation of the total period considered, the Surface runoff, Base flow and percolation are found out to be around 38%, 18% and 24% respectively.

ABSTRACT: The performance of two popular watershed scale simu-lation models – HSPF and SWAT – were evaluated for simulating the hydrology of the 5,568 km2 Iroquois River watershed in Illinois and Indiana. This large, tile drained agricultural watershed pro-vides distinctly ...

Abstract: The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds ...

... Data Distribution System, National Center for Earth Resources Observation and Science (EROS), USGS (http://seamless.usgs.gov/) and processed with ... in which measured values equals estimated values (perfect fit), rather than to the best-possible-fit regression line (Saleh et al ...

The basic flow rate is characterized by an important hydrological component being responsible for the estimation of the water recharge. Due to the difficulty of measurement, mathematical methods are used to calculate the flow separation. However, when hydrographic analysis is based on long historical series, the use of these methods becomes impracticable, making it necessary to use computational resources. A WebGIS (Web Geographical Information System) was developed for data selection and calculation of base flow separation, based on hydrological data from fluviometric stations located in the Taquari-Antas basin, located in the state of Rio Grande do Sul. A modified version of the Unified Process was used as a software development methodology. We used the MVC software architecture standard and the programming languages PHP 7.0, HTML5, JS and CSS3 for programmatic development of the constituent layers of the system. The hydrological data comes from the HIDROWEB portal, part of the National Information System on Water Resources (SNIRH), with hydrological information collected by the National Hydrometeorological Network (RHN) coordinated by the National Water Agency (ANA). The system facilitates the use of remote and distributed hydrological data, shared over the Internet, for various hydrological analyzes.

A plane wall-jet flow is numerically investigated and compared to experiments. The measured base flow is matched to a boundary-layer solution developing from a coupled Blasius boundary layer and Blasius shear layer. Linear stability analysis is performed, revealing high instability of two-dimensional eigenmodes and non-modal streaks. The nonlinear stage of laminar-flow breakdown is studied with three-dimensional direct numerical simulations and experimentally visualized. In the direct numerical simulation, an investigation of the nonlinear interaction between two-dimensional waves and streaks is made. The role of subharmonic waves and pairing of vortex rollers is also investigated. It is demonstrated that the streaks play an important role in the breakdown process, where their growth is transformed from algebraic to exponential as they become part of the secondary instability of the two-dimensional waves. In the presence of streaks, pairing is suppressed and breakdown to turbulence is enhanced.

In 1988, the Florida Institute of Phosphate Research (FIPR) funded project to develop an advanced hydrologic model for shallow water table systems. The FIPR hydrologic model (FHM) was developed to provide an improved predictive capability of the interactions of surface water and ground water using its component models, HSPF and MODFLOW. The Integrated Surface and Ground Water (ISGW) model was developed from an early version of FHM and the two models were developed relatively independently in the late 1990s. Hydrologic processes including precipitation, interception, evapotranspiration, runoff, recharge, streamflow, and base flow are explicitly accounted for in both models. Considerable review of FHM and ISGW and their applications occurred through a series of projects. One model evolved, known as the Integrated Hydrological Model IHM. This model more appropriately describes hydrologic processes, including evapotranspiration fluxes within small distributed land-based discretization. ...