Hydrologic System Analysis
To meet the nation's various expectations, comprehensive approaches should be taken toward basin management. The study should include flood control, water resources development, base flow control, and water environment conservation. Nippon Koei provides sophisticated analysis tools for this purpose. A number of models ranging from SHER, a simplified model, to NK-CBM, a cell-based state of the art model are to be used at different study stage.
◆ Flood Control / Risk Management
To improve the accuracy and reliability of flood prediction land-use, vegetation, soil property and groundwater table depth are also taken into account. Various types of measures like infiltration facility, detention pond, river works or their combinations can be evaluated comprehensively.
◆ Water Resources Development / Base flow Control Analysis
Discharge or stage at any location and any time can be simulated with respect to the state of intake, effluent, well, water supply and sewage. The effect of groundwater level decrease upon river flow, spring water can also be evaluated.
◆ Water Environment / Ecosystem
The transport of pollutants coming from either point or non-point sources can be simulated. The mechanisms considered include sedimentation, flushing, decomposition etc., as well as advection and dispersion. BOD, COD, T-N, T-P and various other water quality indexes are computed for key points or sections, and assessment of the effect of applying alternative practices can then be carried out by comparing these indexes.
2D/3D Numerical Simulation of Flow, Water Quality and Sediment Transport
Various problems in the waters can be studied and analyzed by Nhydro2D/3D model. NK-hydro2D/3D is a hydrodynamic modeling system for two dimensional (2D) and three dimensional (3D) flow and the associated phenomena. The model is based on a boundary-fitted orthogonal curvilinear coordinate system. Besides the hydrodynamics of free surface water flow, density stratification, sediment and water quality transport can be simulated by the model.
◆ River Course (River Consultation, Local Flow and Scouring, etc.)
The NKhydro2D/3D is just the right hydrodynamic model for the river consultation, etc. Incorporated with the information on river configuration, bed material, vegetation, river structure and so on, water surface level, velocity and bed deformation can be predicted by the NKhydro2D/3D model.
◆ Enclosed Waters (Water Quality, Muddy Water, Eutrophication, etc.)
The NKhydro2D/3D model can also be applied to the enclosed waters with density stratification, muddy water, eutrophication phenomena, etc. Decision on the facilities and their operations for inflow, withdrawal and effluent control can be supported by the simulation results.
◆ Reservoir (Sedimentation)
A three dimensional model is desired in the prediction of sedimentation and local transport near the outlet in reservoir. The NKhydro3D model can be employed to study the 3D free water surface problem and to investigate the outlet performance and its operation for sediment and muddy water release, etc.
