GeoHECRAS Update: December 28, 2017 Release

GeoHECRAS 2D Update

Dec 28, 2017 Release

We are pleased to announce a major new release that contains numerous new features, enhancements, and functional fixes for GeoHECRAS. Many of these items came from receiving valuable feedback from our users.

This new release took much longer than we expected, as the 2D modeling capabilities that we added to GeoHECRAS was a “heavy lift” for us. However, the 2D modeling capabilities that we included are “best in class”, far exceeding the capabilities contained in HEC-RAS 5.0 and other commercial 2D modeling software. A description of these capabilities are provided below. For example, we have improved on the 2D meshing capabilities of HEC-RAS, allowing the 2D mesh that GeoHECRAS creates being more stable and much more computationally efficient. In addition, unlike other 2D modeling software, minimal user interaction is required while constructing the mesh—because the software automatically detects and fixes any “bad” or “poorly formed” mesh elements during mesh construction.

As you start to explore these new features and enhancements made to the software, please provide feedback. I will guarantee you that we will take your suggestions to heart as we continue to add capabilities and enhancements to this software.

What’s New

HEC-RAS 2D Modeling

The software now includes the ability to perform 2D unsteady flow modeling and combined 1D and 2D unsteady flow modeling using the HEC-RAS 2D analysis engine. The 2D flow modeling capabilities of the software can be used for:

  • Detailed 2D channel and floodplain modeling
  • Combined 1D channels with 2D floodplain areas
  • Combined 1D channels and floodplains with 2D flow areas outside of the levees
  • Connect 1D reaches into and out of 2D flow areas
  • Connect a 2D flow area to 1D storage area with a hydraulic structure
  • Multiple 2D flow areas in the same geometry
  • Connect multiple 2D flow areas with hydraulic structures
  • 2D dam breach analyses
  • 2D levee breach analyses
  • 2D bridge modeling (without pressure and bridge deck overflow)
  • Mixed flow regimes (e.g., subcritical and supercritical regions, hydraulic jumps, etc.)

Adaptive 2D Mesh

In addition to HEC-RAS’ default rectangular (structured) 2D computational mesh, the software can also create an adaptive 2D mesh to better represent more complicated 2D flow conditions and structures. The software will automatically refine the 2D mesh when required, such as at a roadway crossing.

Adaptive 2D Mesh Refinement

 

2D Mesh Feature Stamping

The software can stamp bridge piers into the 2D mesh. Supported pier shapes include:

  • Circular pier
  • Rectangular round nosed pier
  • Rectangular sharp nosed pier
  • Rectangular square nosed pier
  • Square pier

The user can interactively place and rotate the bridge pier relative to the roadway crossing.

2D Mesh Feature Stamping

 

2D Ineffective Flow Areas

Ineffective flow areas can be assigned to the 2D mesh using polylines or polygons. Alternatively, the user can draw ineffective flow areas on the Map View. For example, stagnant flow areas at roadway crossings can be stamped into the 2D mesh to account for the ineffective flow area. The software will automatically refine the 2D flow area to incorporate the ineffective flow area shape.

2D Ineffective Flow Areas

 

2D Conveyance Obstructions

Conveyance obstructions can be assigned to the 2D mesh using polylines or polygons. Alternatively, the user can draw conveyance obstructions on the Map View. For example, buildings and other structures can be stamped into the 2D mesh as conveyance obstructions to account for flow blockage. The software will automatically refine the 2D flow area to incorporate the conveyance obstruction shape.

2D Conveyance Obstructions

 

Auto Fixing 2D Mesh Bad Elements

The US Army Corps of Engineers HEC-RAS software generates 2D meshes that contain elements that are marked “bad” and that require the user to manually fix. GeoHECRAS will automatically detect and fix these bad elements without requiring any interaction by the user.

Auto Fix 2D Mesh Bad Elements

 

Remembering 2D Mesh User Edits

As the user manipulates the 2D mesh by inserting additional elements, moving elements, and other mesh element editing, the software remembers these edits. Then, the next time the 2D mesh is rebuilt, these user-defined changes are automatically incorporated into the mesh.

Remember 2D Mesh User Edits

 

Assign Land Cover Data as Manning’s Roughness

The software can assign either user-defined land cover polygons or National Land Cover Database (NLCD) data as Manning’s roughness to cross sections and 2D flow areas. The National Land Cover Database provides land cover data for the entire United States. The software can dynamically download a NLCD raster land cover grid for the area being modeled. Each 75ft x 75ft land cover grid cell represents a specific land type. Up to 20 different land types and corresponding Manning’s roughness values are provided.

Assign Land Cover Data as Manning’s Roughness

 

Flood Hazard Mapping

The software can create a flood hazard map, based upon user-selected criteria. The following analysis result variables can be plotted as a flood hazard map:

  • Flood Arrival Time
  • Depth x Velocity
  • Depth x Velocity²
  • Flood Duration
  • Flood Recession Time
  • % Time Inundated
  • Velocity

For the above result variables, the user can define a threshold depth in which the flood hazard map boundary is initiated.

Flood Hazard Mapping

 

Animated Flood Maps

For unsteady flow models, the flood map can be animated to show how it changes with time. The animation speed can be adjusted, as well as setup to continuously loop. The final animation can be recorded to a video. In addition to animating the flood results, options are available to show the maximum and minimum flood extents.

Animated Flood Maps

 

Velocity Vector Maps

The software can plot velocity vectors on the flood map to represent the flow field for both 1D river reaches and 2D flow areas. The velocity vector length is adjusted to represent the velocity at that point. Velocity vector maps can be created for both steady flow and unsteady flow models.

Velocity Vector Maps

 

Particle Tracking Maps

The software can plot moving particles on the flood map to represent the flow field for both 1D river reaches and 2D flow areas. The size and speed of the particle is adjusted to represent the velocity at that point. Particle tracking maps can be created for both steady flow and unsteady flow models.

Particle Tracking Maps

 

Google Earth Map Animation

The software can export out the flood map animation to Google Earth. This is helpful for presentations on flood risk assessment and flood management.

Google Earth Map Animation

 

Georeference Lateral Structures Command

Additional functionality has been added to the Georeference Lateral Structures command, including the ability to draw a portion of the revised lateral structure alignment polyline and intersect the original lateral structure alignment at two locations to define the change between the points of intersection.

Georeference Storage Areas Command

Additional functionality has been added to the Georeference Storage Areas command, including the ability to draw a portion of the revised storage area boundary polyline and intersect the original storage area boundary polyline at two locations to define the change between the points of intersection.

River Channel Modification Command

The River Channel Modification command allows the user to define a trapezoidal cut into the existing channel geometry. The user can see a profile view of the channel modification along the river, and can either draw the channel bottom, define a channel bottom slope to use, or instruct the software to interpolate the channel bottom between selected cross sections. The user can have the channel modification follow along the existing river centerline, or select a new alignment polyline to use—like when performing stream channel restoration back to a sinuous river path.

After the changes have been added to the river channel, a HEC-RAS analysis can be performed to see what affect these changes have on the computed water surface elevation, depth of flow, velocity, and shear stress. This command can be used by the user in performing stable channel design and for fish waterway and passage design. In addition, bendway weirs and other artificial structures can be easily inserted into the channel to adjust the flow characteristics of the stream, stabilize the channel from horizontal migration, and create habitat areas for fish.

River Channel Modification

 

Graphical Editing of Roadway Geometry

The software now allows the user to graphically edit in the Bridge & Culvert Data dialog box the roadway crossing high and low chord geometry. If there is no low chord geometry defined, then the high chord geometry can be moved vertically and horizontally. However, if both high and low geometry are defined, such as at a bridge opening, the high and low geometry can only be moved vertically.

LIDAR Processing

The Process LIDAR command has been extended to allow assignment of a CRS to the processed LIDAR file.

Delete Scenarios

This new command allows the user to select which plans (scenarios), geometry, and flow data to remove from a project. In addition, it automatically compresses the database to shrink the size of the project file.

Additional Map Edit Commands

The following GIS editing commands have been added, allowing the user to manipulate map data:

Edit Polylines

  • Simplify Elements
  • Intersect Polylines
  • Detach Polylines
  • Distribute Vertices

Edit Polygons

  • Simplify Elements
  • Intersect Polygons
  • Detach Polygons

Layer Transformation and Registration

Surveyors use a NOAA online software program called OPUS that takes measured GPS grid coordinates from a survey data collector and convert them into local ground coordinates that are corrected for the true shape of the Earth (which is not a perfect sphere). AutoCAD Civil3D provides support for the transformation scale factor in its Drawing Settings dialog box. We have implemented support for this transformation scale factor throughout the software, including CAD layers, TIN layers, HEC-RAS layer (and other layers) Properties dialog boxes, allowing the software to support local ground coordinates.

In addition, the user can manually register a layer’s position by providing two coordinate points (i.e., current location and desired location).

Minor Loss Coefficients

Minor losses due to bends, junctions and more can be accounted for in both steady flow and unsteady flow analysis. Minor loss coefficients can vary between 0.0 and 1.0. This loss coefficient gets multiplied by the velocity head at that the cross section it is defined at to compute the minor energy loss. This energy loss gets added to the energy equation for steady flow computations. For unsteady flow computations, the energy loss is converted to an equivalent force and inserted into the momentum equation. In both cases, the energy loss is assumed to act as a force in the upstream direction to slow the flow down.

Internal Changes in WS and EG

Internal boundary conditions can be defined at a cross section, on a profile by profile basis, by defining one of the following:

  • Change in water surface elevation
  • Change in energy gradeline elevation
  • Additional energy head
  • Known water surface elevation
  • K loss

What’s Updated

Interpolate River Geometry Command Improvements

With this updated command, the user can select an individual river reach or a portion of a river reach when interpolating the river geometry. When dealing with large models with numerous river reaches, the user may only want to work on a single reach or even a small portion of a river reach. The user can now select an individual reach for generating the interpolated river geometry, thereby vastly speeding up the process.

Generate Terrain Command Improvements

With this updated command, the user has more control over the file format that is created and saved. These other file formats can be used in other software. For example, the software now generates a GeoTIFF elevation grid that is more easily shared with other software. In addition, the generated terrain elevation grid can handle large areas than before.

In addition, the command has been sped up by 200% by inline parallel processing optimization. As such, grid limits have been increased to 50,000 x 50,000 cells which generates a 9-gigabyte elevation grid (in under 20 minutes).

When creating terrain models and flood map results, the user can now specify down to one-tenth of a foot or meter resolution accuracy.

Cross Section River Stationing Renumbering Improvements

The Edit River Stations, Node Names, & Descriptions command has been improved to allow the user to select a series of connected river reaches and junctions, and renumber the cross sections and junctions contained along the selected reaches. In addition, the user can select a reference cross section to base the renumbering on rather than only on the downstream most cross section. In that way, the user can reference a known FEMA FIS cross section for performing the renumbering on.

Improved Flood Map Command

With this updated command, the user can select a portion of a river reach for creating a flood map. When dealing with large models, the user may only want to work on a small portion of a river reach. The user can now select a section of the reach for generating the flood map, thereby vastly speeding up the process.

When creating terrain models and flood map results, the user can now specify down to one-tenth of a foot or meter resolution accuracy.

Improved Draw Cross Sections Command

This improved command greatly speeds up the creation of cross sections by automating the process of determining the river station ID, flow lengths, and bank stations. The user can draw cross section after cross section without needing to intercede and define other parameters.

Remembering Data Dialog Box Maximized/Minimized State

The data dialog boxes, such as the Cross Section Data dialog box, allow the user to specify whether to show the cross section plot in the dialog box, or minimize the dialog box so that it is smaller and does not show the cross section plot. The software now remembers this state for each of the various data dialog boxes during the application session.

Build Bridge Opening Command

During the process of designing a bridge opening, the software remembers what was used previously. In that way, it allows the user to more effectively size a bridge opening to a roadway crossing.

Additional CRS Support

Additional coordinate reference systems (CRS) have been added, including Indiana Geospatial Coordinate Systems (InGCS). Also, round tripping of AutoCAD drawings are more fully supported with embedded CRS.

Enhanced Split Polylines command

River reaches can now be split using the Split polylines command. Similarly, cross sections can be trimmed using the Split polylines command.

Editing Polygon Shared Borders

Editing of polygons that have shared borders (or edges) is now supported. Moving a vertex on a shared border changes the adjacent polygons.

Data Grid Improved AutoFill

All data grids (or tables) support complete AutoFill (or sometimes called drag-fill) functionality, as is provided in Microsoft Excel and other spreadsheet software. AutoFill series, like 5-Year, 10-Year, 15-Year, are fully supported.

  1. Enter a value into the starting cell;
  2. Use the mouse to drag the ‘fill handle’ (the small black square at the bottom right of the start cell) down the column over the range of cells to be filled;
  3. When you drag the ‘fill handle’ across the range of cells to be filled, the software will automatically fill the selected cells, by either repeating the value in the first cell or by inserting a sequence from the first cell value (e.g., Year 1, Year 2, Year 3, …);
  4. To have the software recognize a series that is not a simple increment by 1, enter the first two values of the series into the first and second cells of a range. Select both cells and again, drag the fill handle across the range to be filled. The software will automatically recognize the pattern from the two initial cells and continue this across the selected range. Using this method, you can get Software to fill cells by increments or decrements of any number (e.g., Year 5, Year 10, Year 15, …).

Conflate Point Data Command

Previously defined point type selection sets are retained. This allows the user to iterate more quickly when developing cross sections from survey points.

Generate Contours Command

This command now has an option to remove redundant vertices. This greatly reduces the size of the constructed contour data while still maintaining the required accuracy.

Generate Contours Command

 

Generate Contours Command

 

Date Selection Dialog Box

The date selection dialog box now allows the user to select the current date by clicking a button.

Date Selection Dialog Box

Floodplain Encroachments Command

The user can interactively select the river reach from the Map View. Similarly, the user can interactively select the upstream and downstream cross sections from the Map View for applying Encroachment Method #4.

Display of Bridge Openings & Culverts

The interior of bridge openings is now filled, making the bridge opening more realistic and less like a wire frame object.

3D View - Bridge Abutment & Interior

 

Bridge abutments and pier locations can be seen from the 2D view. Similarly, culvert locations can be seen from the 2D view.

2D View - Bridge Abutment & Piers

User Defined Limits

Many commands require the user to select the limits for processing, such as generating contours. These commands now remember the last-defined user limits.

AutoCAD Civil 3D 2018 Support

The software supports the new AutoCAD Civil 3D 2018 file format, including display of Civil 3D objects.

What’s Fixed

Export HEC-RAS to CAD Command

Loading an exported AutoCAD drawing file into Civil 3D causes the HEC-RAS model data to zoom away from the current view. This issue has been corrected.

Navigate Backward & Forward commands

These commands were not keeping track of the 2D & 3D view modes. This issue has been resolved.

Lateral Structure Creation

There were some issues regarding creation of lateral structures. These issues have been resolved.

Lateral Structure IDs and Inline Structure IDs

The software now maintains the same river stationing nomenclature as used for cross sections. For example, if the cross section river stationing formatting is defined using integer feet, the same is applied for newly created lateral structures and inline structures.

Merging River Reaches

Merging of river reaches sometimes caused issues with cross section river stationing. These issues have been resolved.

Draping of Computed Water Surface Contours in Google Earth

Software was incorrectly draping the computed water surface contours in Google Earth. Now they are written out at their computed elevations.

Allow Negative River Stationing

Cross sections and other river elements now support negative values for river station IDs.

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About the Author Chris Maeder

Chris Maeder

Chris is an experienced civil engineering and software technology leader, with over 30 years industry experience. With proven expertise in global software development, he has built engineering teams that adapt quickly, focus on what’s important and, most importantly, deliver. He is a licensed professional civil engineer with extensive experience in water resource engineering. He has performed and supervised engineering projects in urban stormwater drainage, transportation and roadway drainage, storm sewer design, detention pond design, stormwater quality, green infrastructure, watershed management planning, wastewater sewers, water distribution networks, pump stations, FEMA flood studies, bridge and culvert design, bridge scour and armoring, dam failure analysis, seepage and groundwater modeling, and environmental permits.