HydroCAD^® Stormwater Modeling - Since 1986

HydroCAD combines the best of TR-20, TR-55, and SBUH, plus built-in hydraulics, graphics, automatic database, and on-screen routing diagram in a single program.  (see comparison table)  The result is the fastest, easiest, and most capable hydrology and hydraulics software available.  We call it HydroCAD because it brings the benefits of Computer Aided Design to hydrology, while not requiring any other CAD software.  However, HydroCAD also offers direct extraction of subarea data directly from AutoCAD^® or BricsCAD^® without any other software.  Details here.

HydroCAD is ideal for all types of drainage projects. From small runoff studies to complex detention pond designs, HydroCAD will help you get the job done - fast! While HydroCAD is great for speeding up your basic TR-20, TR-55, and SBUH studies, it excels when it comes to sophisticated features like these:

For most applications, we recommend our complete 20-node permanent license for just $895, or $375 for a 20-node annual license. With HydroCAD's unique expandable design, any system can be easily enlarged (up to 1000 nodes) as needs and budget grow.

Click here for pricing.  After your first project, you'll understand why HydroCAD has provided the competitive edge in hydrology since 1986.

Interactive Hydrograph Modeling!

HydroCAD is an integrated solution for the analysis, design, and documentation of complete drainage systems using standard hydrograph techniques. Compared to other programs that require several separate modules, HydroCAD is faster, easier to use, costs less, and does so much more. Here is a brief overview:

On-Screen Routing Diagram
Exclusive on-screen routing diagram shows the interconnections between the subcatchments, reaches and ponds that make up each watershed.  This eliminates the need to manually prepare a flow diagram and makes routing changes a snap. Automatic diversions are shown right on the diagram as a secondary or tertiary outflow.  And a "discarded" outflow is available for exfiltration losses.  Hydrographs are automatically generated, summed and routed based on the diagram. Design changes are automatically propagated throughout the system with the minimal re-calculation feature, much like a spread-sheet. On-screen diagram also provides a simple point and shoot interface for quick data entry, calculations, reports and graphics.  The diagram can also be annotated with text and custom images.

SCS Runoff
Generates complete runoff hydrographs using the SCS Unit Hydrograph procedure. Provides full TR-20 runoff compatibility and improved accuracy over the old TR-55 tabular method. Extensive rainfall library includes SCS type I, IA, II, and III, plus Florida, Illinois, and many other storms,.  You can also download local rainfall data and generate custom synthetic rainfalls, or setup custom storms if required.  Long time spans are accurately handled with unlimited hydrograph points.

Santa Barbara Urban Hydrograph
Switch or compare runoff methods at any time.  The SBUH method can be used with any rainfall distribution, and works together with all the other features described here.  Allows separate runoff calculation for pervious and impervious areas.

Curve Number Weighting
Each subcatchment allows an unlimited number of  sub-areas, each with fully automatic curve number lookup from the SCS/NRCS curve number tables.  Extensive on-line help includes complete listing of hydrologic soil groups.   Composite CN value can be calculated for all sub-areas, or separated according to pervious and impervious areas.   Or use the "weighted-Q" option to perform separate runoff calculations for each CN value.  CN values can be automatically adjusted for unconnected impervious areas.  Curve number usage can be reported on a project-wide basis.

Time of Concentration
Each subcatchment may have an unlimited number of  flow segments, using any combination of Tc procedures including  TR-55 sheet flow, shallow concentrated flow, upland method, lag method, channel flow, plus direct entry of circular, rectangular, vee, trapezoidal, and parabolic channels.  Sheet flow length can be determined by the McCuen-Spiess procedure.  Travel time can also be calculated for lakes and reservoirs.

Multiple Events
Each project can have an unlimited number of rainfall events (2-year, 5-year, water-quality, etc), allowing easy event changes and multi-event reporting.  Events can be automatically defined for most counties in the United States.

Rainfall Management
Rainfall reports display depth or intensity in tabular or graphical format.  Displays multiple storms at once for easy comparison.  Works with all standard and custom rainfall tables, plus local rainfall data from NOAA, NRCC and other sources.  Built-in rainfall editor makes it easy to create custom rainfall definitions, or create synthetic storms automatically from local rainfall data..

Unit Hydrographs
HydroCAD includes a library of common unit hydrograph tables, including the SCS UH (peak factor=484), Delmarva UH (PF-284), and many others.  Unit Hydrograph reports provide graphical and tabular representations, with the ability to compare and create custom UH definitions.  Although most projects will use the same UH for the entire project area, HydroCAD 10.1 also provides the ability to specify a different Uh for each subcatchment.

Rational Method
Generates trapezoidal hydrographs using the Rational Method or Modified Rational Method, with fully adjustable rise/fall rates.  Automatic IDF curve management with frequency factors and critical-duration analysis.  Supports rainfall data from NOAA, NRCC, and other web sites.  Switch instantly between SCS and Rational Method at any time for a quick comparison of results.  (Although the SCS method is preferred for routing, Rational Method is sometimes used for pipe sizing.)

Land-Use Analysis and Pollutant Loading Calculations
Each sub-area can be associated with a specific land-use and pollutant concentrations, allowing automatic land-use reporting and pollutant loading calculations.  Options include single-event loading or annual loading by the Simple method. Details here.

Reach Routing
A reach is frequently modeled as a flow segment within a subcatchment. Alternatively, a separate reach routing may be performed for rectangular, vee, trapezoidal, and circular channels.  Other shapes can be modeled using a custom cross-section (with constant or variable Manning's value), or by based on wetted perimeter or gauge data.  Several reach routing procedures are available, including Muskingum-Cunge as used in the current Win-TR-20 release.   Circular channels (pipes) can be automatically sized for peak flow, or a full culvert analysis is available by using a pond with culvert outlet.

Pond Routing
Automatic hydrograph routing for any "pond," from a small catch basin to a large lake.  Basic pond routing is performed by the storage-indication method (same as the Modified Puls method or Level Pool routing).  For more complex situations involving tailwater dependencies, interconnected ponds, or even tidal tailwater effects, HydroCAD also provides a dynamic storage-indication routing or simultaneous routing procedures.

Outlet Hydraulics
Automatically calculates pond stage-discharge curves for weirs (broad crested, sharp-crested, V-notch, trapezoidal, rectangular, and custom), culverts (round, box, arch or elliptical, under all flow conditions), orifices (horizontal or vertical), orifice arrays (grates & perforations), custom weir/orifice devices, overlapped (compound) weirs, vortex valves, rotary weirs, tubes, siphons, skimmers, constant-flow outlets, and user-defined devices. Devices may be combined to model complex devices like stand-pipes, with automatic transition from weir to orifice flow depending on head. Individual devices may be directed to a secondary or tertiary outflow and routed separately to create a diversion.  Outlet devices may operate with fixed, differential, or dynamic (automatic) tailwater.

Exfiltration Calculations
Infiltration effects can be modeled as a pond with an exfiltration outlet.  Options include fixed flow, velocity, or conductivity, which can be applied to the surface area or wetted area.  To allow for impervious areas, exfiltration may be limited to specific storage volumes and/or elevation range.

Pump & Siphon Routing
Complete pump modeling and hydrograph routing based on the pump rating curve, on/off elevations, pipe loses, and even tailwater effects.  Also models self-priming siphons, with user-defined start and break elevations under any tailwater condition, including dynamic tailwater.

Pond Storage
Automatic storage calculations for common shapes including cones, prismatic shapes, vertical and horizontal cylinders, pipe storage, and arched chambers.  Custom storage volumes may be entered directly or calculated from surface areas.  Any storage volume may be adjusted for void space to allow for backfill, such as crushed stone.  Volumes may be embedded in each other to model complex storage arrangements, such as stormwater chambers or perforated pipe buried in a stone bed.  Displaced volume can be automatically adjusted for thick-walled (concrete) storage chambers.

Storage Chambers
HydroCAD has built-in support for a wide range of prefabricated storage chambers.   Chambers can be embedded in stone, with automatic calculation of overall stage-storage relationship, including the displacement of thick-walled concrete chambers.  Chamber wizard performs automatic chamber layout, modeling, and cost estimates for 100's or predefined chambers, including automatic handling of end-caps, start/end chambers, and even pipe storage.  Graphical and tabular reports make it easy to view and compare available chambers, or create custom chamber definitions.

Special Pond Design Features
A special pond sizing report estimates the storage required to reduce pond outflow to any desired rate.  For compliance with water quality requirements, detention time is calculated using the center-of-mass and plug-flow methods.  Other detention requirements can be verified by using the tabular routing results.

Flexible Pipe Modeling and Automatic Sizing
HydroCAD can handle most any pipe geometry, including box, circular, elliptical, and pipe-arch.  Partially-filled culverts are easily modeled by specifying the fill depth.   Pipes can be automatically sized for pipe-full conditions, or to achieve a specified headwater.  Pipes are sized up and/or down using any desired increment and minimum size.

Hydrograph Link
A manual link provides the ability to enter any arbitrary hydrograph, such as a pre-defined off-site flow. An import link will read a hydrograph directly from a file. And an automatic link can interconnect separate routing diagrams when analyzing large or complex drainage systems. A link can also be used to establish a flow threshold, to scale a hydrograph peak or duration, to define a tidal tailwater condition, enter an arbitrary table of tailwater vs. time, or delay a hydrograph by a pre-set time.  Details here.

Powerful Data Entry
Data entry is quick and easy with advanced  features such as table editing, built-in Manning's lookup table, and load/save from spreadsheet files.  Each screen is linked to a specific help page with full details on every parameter and equation.  Default values make it easy to handle common day-to-day tasks, while advanced parameters (like adjustable Ia/S ratio) allow modeling of special situations.  Subcatchment data can be automatically extracted from site plans using the Carlson Hydrology.

Graphics & Reports
Creates instant reports and graphics on your screen or printer.  Report Generator produces multi-page reports with automatic formatting, page headings, page numbering, and project revision date.  Project notes and detailed node notes let you include narratives and other documentation within each HydroCAD report.  Node comparison reports show existing vs. proposed conditions in tabular or graphical format.   Supports all Windows printer drivers, including plotters, fax, and PDF drivers.  See sample reports in PDF format:  Routing Diagram, Subcatchment, Reach, Pond, Link, Node Listing

Advanced Reporting
The node profile report makes it easy to verify the elevation settings for any node.  Or you can use the node comparison report to see the profile of multiple nodes side-by-side.

Flexible Input/Output Formatting
Independent selection of English/US or Metric units for data entry and reporting.  Units and decimal places are easily customized as required.

Data Import
Imports external hydrograph files in a number of different formats.  Automatic import and conversion of TR-20 data files.  Tabular watershed import including subareas, curve numbers, and Tc data.  Imports subarea data directly from AutoCAD^® or via Carlson Hydrology.  Details here.

Data Export
Reports and graphics can be exported in a wide range of file formats including TXT, BMP, EMF, WMF, and JPEG.  Hydrographs and other numerical results may be exported in CSV format for use with spreadsheet applications.  Automatic data export options allow data for an entire project (including all rainfall events) to be automatically exported each time the project is opened, allowing dynamic links with other software, database applications, or custom reports.  HydroCAD-10 also provides tabular export of watershed data, including subareas, curve numbers, and Tc parameters.

Automatic Data Management
Projects can be stored on any local or network storage device, and can be opened directly from Windows, as well as within HydroCAD.  HydroCAD can open multiple projects simultaneously, for easy comparison or transfer of data.  Automatic timed backup protects against system failures.  Each project is stored in a single, compact ASCII file for easy data management and exchange.  This allows easy transmission as an email attachment, which can be directly opened on any computer with HydroCAD installed, including the free HydroCAD Sampler.  (Sampler users can view but not save projects with more than five nodes.)

Runs on Any Personal Computer
Runs on virtually any PC from Windows XP to Windows 10.  Details here.  Compact, sixty-second installation with no system changes.    Does not require other CAD software, but includes extensive data import and transfer capabilities.

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