There is a lack of Ordinary Differential Equation (ODE) formulations in numerical hydrology, contributing to the application canned adaptive timestep solvers; hence continued dominance fixed (e.g., Euler) techniques despite their fundamental problems. In this paper, we reformulate Dynamic-TOPMODEL into constraint-handling ODE form and use MATLAB's advanced ODE-solvers solve resulting system equ...

In uncon®ned aquifers ¯owing under topographic gradients, the water table is a subdued replica of the ground surface above. This principle is the basis for using detailed collateral or secondary information from digital elevation models to supplement sparse observations from water wells in the mapping of phreatic surfaces. Data from DEM-derived secondary variables are incorporated into the esti...

In this paper, we discuss the problem of calibration and uncertainty estimation for hydrologic systems from two points of view: a bottom-up, reductionist approach; and a top-down, data-based mechanistic (DBM) approach. The two approaches are applied to the modelling of the River Hodder catchment in North-West England. The bottom-up 5 approach is developed using the TOPMODEL, whose structure is ...

TOPMODEL rainfall-runoff hydrologic concepts are based on soil saturation processes, where soil controls on hydrograph recession have been represented by linear, exponential, and power function decay with soil depth. Although these decay formulations have been incorporated into baseflow decay and topographic index computations, only the linear and exponential forms have been incorporated into i...

By increased rural-urban migration in many African countries, the assessment of changes in catchment hydrologic responses due to urbanization is critical for water resource planning and management. This paper assesses hydrological impacts of urbanization on two medium-sized Zimbabwean catchments (Mukuvisi and Marimba) for which changes in land cover by urbanization were determined through Lands...

Three geographic information system GIS -based distributed hydrological models were developed for flood simulation and forecasting in a subbasin of the Yellow River. A grid-and-topography-based distributed hydrological physical model, i.e., the GTOPMODEL model, is described that includes vegetation and root interception, evapotranspiration, and runoff generation via the saturation excess mechan...