Table of Contents
LibHydro is a library of
subroutines that perform calculations commonly used in hydrologic engineering.
These subroutines are identical to those used in the U.S. Army Corps of
Engineering Hydrologic Engineering Center's “HEC” series (e.g. HEC-HMS and HEC-RAS)
and have been implemented throughout the world for the past 40 years. In
1995, the Hydrological Engineering Center isolated several of FORTRAN subroutines
that perform particular hydrological procedures in the HEC-1 simulation model and
later these were packaged into a
Dynamic Link Library (DLL) file called “libHydro.dll”. Packaging the
subroutines in a DLL file allows the HEC subroutines to be used in custom programs.
LibHydro is not a supported system of the HEC and if there are questions about
it, please direct them to CRWR.
What is a Dynamic Link Library?
A Dynamic Link Library, or DLL, file is a library of functions or subroutines that can be called from a executable file (.exe). A DLL can be called by a program written in FORTRAN, C, C++, Visual Basic, or any other COM-compliant language. For example, a DLL file written in FORTRAN can be called from an EXCEL macro to perform a hydrologic calculation. Likewise, ArcMap, ArcCatalog, or Access can also call functions or subroutines stored in a DLL file.
What hydrologic functions are available in LibHydro?
Lib Hydro subroutines are classified into 6 groups: Precipitation, Loss Rates, Unit Hydrographs, Base Flow, Routing Methods, and Utility. Follow the links below to learn more about each subroutine and to test the subroutine using EXCEL.
|
Category |
Subroutine Name |
Subtitle |
|
LossRates |
Losses Using Green and Ampt Infiltration Formula |
|
|
|
Initial Loss and Constant Loss Rate |
|
|
|
SCS Curve Number |
|
|
Unit Hydrograph |
Clark Unit Hydrograph |
|
|
|
Snyder Unit Hydrograph |
|
|
|
SCS Dimensionless Unit Hydrograph |
|
|
|
KWaveRunoffTransform |
Kinematic Wave Runoff Transform |
|
Baseflow |
Base Flow using HEC1 Method |
|
|
RoutingMethods |
Muskingum Routing |
|
|
|
RoutePulsChannel |
Modified Puls Channel Routing |
|
Utilities |
Distance Between Two Points on Earth |
Note: Kinematic Wave Runoff and Route Puls Channel
functions have not been called yet by Visual Basic because of unsolved
errors. For updates visit
http://civilu.ce.utexas.edu/stu/takamam/lh_home.htm.
Hydrologic Modeling with Model Builder and LibHydro
Arc Hydro is designed to bring the world of GIS and Hydrologic Modeling closer together. Presented on this CD is an ArcGIS 9.0 custom toolbox that reads information from Arc Hydro Watershed and TimeSeries data, and runs hydrologic simulation processes using HEC's library of HEC-1 subroutines, known as libHydro. For more information about the ArcGIS 9.0 custom toolbox, please see the document "Hydrologic Simulation with Arc Hydro, libHydro, and Model Builder" included on this CD.
Masatsugu (Takkan) Takamatsu
Graduate Research Assistant
Center for Research in Water Resources
Department of Civil Engineering, University of Texas at Austin
(512) 471-0073
Tim Whiteaker
Graduate Research Assistant
Center for Research in Water Resources
Department of Civil Engineering, University of Texas at Austin
(512) 471-0073
These materials may be used for study, research, and education, but please credit the authors and the Center for Research in Water Resources, The University of Texas at Austin. All commercial rights reserved. Copyright 2003 Center for Research in Water Resources.