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WMS (Watershed Modeling System)
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Modelarea fiecarei faze a hidrologiei si a hidraulicii bazinelor hidrografice |
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descriere detaliata (temporar
numai in limba engleza) |
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Automated Watershed Delineation |
Using digital terrain data, WMS can automatically delineate a watershed and
sub-basins. As part of the delineation process, basin data such as area, slope,
mean elevation, maximum flow distance, and many other commonly-used hydrologic
parameters are automatically computed. A new Delineation Wizard has been added
to WMS to guide first-time or novice users of the software through the
delineation process. However, many advanced features and options are included
in WMS:
- Use DEMs (grids) or TINs for delineation. You can easily manipulate the
elevation data in either type of dataset.
- Add any number of interior outlet points and let WMS subdivide the
watershed automatically.
- Manipulate stream networks to represent man-made features or proposed
changes in the watershed.
- Override derived basin boundaries to match your knowledge of the
watershed.
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As part of the delineation process, WMS finds all flow paths on the entire
terrain model. This allows you to inspect flow patterns anywhere inside of
outside your watershed. Further, the longest flow path in each sub-basin is
stored for use with the Time of Concentration Calculator. No other system
available will match the accuracy and flexibility of the delineation functions
in WMS! |
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GIS Tools |
WMS will allow you to take advantage of all types of GIS data available for
hydrologic and hydraulic modeling. The GIS module of WMS 8 includes a complete
set of tools for importing, creating, and manipulating GIS vector and raster
data. ArcGIS/ArcView is not a required component of the WMS software! You will
find that WMS can work with your GIS data effectively with or without ArcGIS. A
few of the powerful tools in WMS include:
- Direct linkage with ESRI’s ArcGIS - this lets you use the powerful data
catalog tools of ArcGIS in conjunction with WMS.
- Terrain data can be created, merged, and manipulated using grids, TINs, or
contour lines.
- Data layers such as land use and soil type can be clipped to match your
watershed.
- Attribute tables can be joined and queried.
- Images (TIFF, JPEG) can be geo-referenced, joined, and clipped.
- Attributes from data layers can be assigned to your model using GIS
overlay operations.
- New “data tree” interface allows you to turn on/off, change display,
change coordinate systems, and review contents of each data layer quickly and
easily.
- Coordinate System Conversions - Convert data between geographic and planar
coordinate systems
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Floodplain Modeling and Mapping |
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Whether you have used WMS to run a HEC-RAS model, a SMPDBRK model or obtained
hydraulic analysis results elsewhere, the tools for floodplain delineation and
mapping in WMS will create the results you need for your flood study. The
powerful interpolation algorithms in WMS allow you to create flood extents and
flood depth maps using digital terrain data and water surface elevation data
points. You can use the fast and easy channel hydraulics tools in WMS to
create approximate (Zone A) maps. If you need a detailed analysis (Zone AE or
AH), you will find the HEC-RAS interface and flood mapping tools are nicely
integrated and intuitive in WMS.
The full process of flood modeling and mapping has been integrated into a
seamless process in WMS. Perform a simulation with any hydrologic model (HEC-1
or HMS, TR-20, TR-55, Rational Method, MODRAT, NFF) and link the peak flow or
complete hydrograph to a HEC-RAS model of the river channel in your watershed.
Complete the set up of HEC-RAS with cross-section cutting, area attribute
mapping (roughness values assigned by polygons), and automated assignment of
thalweg and bank locations and downstream distances. Once a HEC-RAS simulation
is completed, you can import the W.S.E. results directly from the HEC-RAS
project files and use them to determine the flooding extents and depths on the
terrain model in WMS.
The input required for a SMPDBK model is a stream centerline, cross sections,
and information regarding the storage and failure of the dam being modeled. WMS
saves the model data to a properly formatted input file for SMPDBK and then
launches the executable. The executable is the same version distributed by the
NWS. |
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Stochastic Modeling |
Uncertainty in modeling parameters can now be analyzed using the automated
stochastic modeling tools in WMS. These tools simplify and automate the process
of varying certain parameters (such as CN or roughness) in a model, creating a
model input file, and running the simulation over and over again. Some
applications of this technology are:
- Use HEC-1 with CN randomization to create probabilistic hydrograph
results.
- Use HEC-RAS with roughness randomization to create probabilistic water
surface elevation results.
- Link HEC-1 and HEC-RAS in series with randomization to create
probabilistic floodplain maps
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2D (Distributed) Hydrology |
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After many years of research and development, a 2D surface/groundwater
hydrologic model is now available in WMS! The GSSHA model is the perfect
solution for studies which require analysis of 2D surface flow and
groundwater/surface water interaction. The model uses a 2D finite-difference
grid to analyze surface runoff, 1D channel hydraulics, and groundwater
interaction in a comprehensive hydrologic cycle model. Water quality and
sediment transport processes may also be modeled with GSSHA. The model is
capable of single event or long term rainfall simulation; radar rainfall data is
supported in either case.
Detailed information about GSSHA can be found at here - from the developers
at the USACE!
Typical applications of this model are:
- Flood forecasting (depth and velocity over entire 2D domain)
- Thunderstorm (localized rainfall) flood analysis
- Surface ponding and infiltration analysis
- Groundwater/surface water interaction modeling
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Data Compatibility |
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Obtaining and formatting digital data is often the most time-consuming task in
watershed modeling. The WMS development team has been hard at work ensuring that
WMS is compatible with as many file formats as possible. Further, they have
dedicated a website to learning about and obtaining GIS data to use with WMS.
Please visit the link below to learn about where to download free data, how to
use it, and other informaiton. WMS
GeoSpatial Data Aquisition - http://emrl.byu.edu/gsda/
Some of the more popular data formats supported by WMS are:
- USGS DEMs - download and use any format of DEM from the USGS.
- USGS NED data - seamless elevation data can be downloaded and read into
WMS.
- ArcGIS Raster (ASCII format) - read elevation or attribute data in gridded
format from ArcGIS.
- ESRI Shape files - read all shapes and attributes into WMS.
- DXF and DWG CAD files - WMS now supports the latest versions of DXF and
DWG.
- TIFF, JPEG images - images along with geo-referencing information can be
read by WMS.
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models |
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The Watershed Modeling System supports several industry-standard, numerical
models to compute peak flow, hydrographs, water quality, etc. Each model is
supported through the Hydrologic Modeling Module with a completely integrated
interface for parameter input, job control, and output review. A model checker
is also featured with each model; this checker guides you to correct errors or
omissions in model input data. The models available for use with WMS are
described below - each model is included with the WMS installation (model
executable files and documentation) and is fully linked with the WMS software. |
HEC-1 (HMS)
Developed by the Hydrologic Engineering Center, HEC-1 is the most
commonly-used lumped parameter model available. HEC-1 is designed to
simulate surface runoff from a single precipitation event. |
National Flood Frequency (NFF)
The National Flood Frequency program, developed by the USGS in
cooperation with FHWA and FEMA, evaluates regional regression equations for
estimating flood peak discharges. |
TR-20
Developed by the NRCS, TR-20 is designed to compute surface runoff
from natural or synthetic rainstorm events. |
Rational Method
One of the simplest and best-known methods of hydrology, the Rational
Method computes peak discharge from an area based on rainfall intensity and a
runoff coefficient. |
TR-55
TR-55 was developed by the NRCS as a simplified method to compute
storm runoff in small, urbanized watersheds. |
HSPF
The Hydrological Simulation Program - FORTRAN simulates hydrologic and
water-quality processes on land surfaces, streams, and impoundments. It is
Often used in the development of TMDLs. |
MODRAT
MODRAT is the specialized Modified Rational Method program used by the
County of Los Angeles, California to compute surface runoff. |
HEC-RAS
HEC-RAS is a 1D hydraulic model for computing water surface profiles for
steady state or gradually varied flow. |
CE QUAL W2
CE QUAL W2 is a 2D (profile) hydraulic model used for water quality analysis
in rivers and reservoirs where vertical variation analysis is required. |
GSSHA
Developed by USACE ERDC, GSSHA is a distributed (2D) hydrologic model
developed for analysis of surface runoff, channel hydraulics, and
groundwater interaction. Water quality and sediment transport are also
supported. |
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SMPDBRK
The Simplified Dam-Break (SMPDBK) was developed by the National Weather
Service (NWS) for predicting downstream flooding produced by a dam failure. |
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WMS modules |
The WMS interface is separated into several modules; these modules contain tools
that allow manipulation and model creation from different data types. Click on
the modules liste below for details of each componenet of WMS:
- Map Module - provides a suite of tools for defining watershed data
in a GIS and then using the information to directly create and manage
hydrologic and hydraulic models, or as a support utility for data development
with either TINs or DEMs.
- GIS Module - (1) if you have license of ArcView (ArcEdior, or
ArcInfo as well) version 8.0 or higher then you can enable the use of
ArcObjects within WMS; (2) if you do not have a license of ArcView 8.0 or
higher then the GIS module will allow you to read in and display shape files
as GIS layers.
- Terrain Data module - a module where you create, edit, and
preprocess all of your digital terrain data, whether it is a TIN or DEM; the
Drainage Module then is used to delineate a watershed from either a TIN or a
DEM.
- 2D Grid Module - is used for surface visualization and for the
development of distributed (2D) rainfall/runoff analytical models
- Drainage Module - it allows you to automatically delineate streams
and watershed/sub-basin boundaries based on the land surface represented by
the DEM or a TIN.
- Hydrologic Modeling Module - is the center for hydrologic modeling
input, execution and output review
- River Modeling Module
- Scatter Point Module - is used to interpolate data from scattered
points to grids or TINs
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