The document describes the development of the Q-RAS plugin, which aims to simplify the preparation of geometry data for HEC-RAS flood modeling within QGIS. The plugin was created because preparing geometry data in HEC-RAS is time-consuming, and most HEC-RAS users are novice GIS users. Q-RAS allows users to digitize river and cross-section layers in QGIS and generate an interchange file for HEC-RAS with one click. The document outlines the motivation, previous related work, the main functionality of Q-RAS, and areas for potential future improvements to the plugin.

1. Motivation
Main contribution
Discussion
Q-RAS: SIMPLE TOOL FOR HEC-RAS
GEOMETRY DATA PREPARATION
AS QGIS CAN BECOME AN HEC-RAS PREPROCESSOR
P. De Rosa1
1
GfosServices SA consulting:
pierluigi.derosa@gfosservices.it
XVI meeting degli utenti italiani di GRASS e GFOSS, 2015
De Rosa P. Q-RAS plugin

2. Motivation
Main contribution
Discussion
OUTLINE
1 MOTIVATION
Why Q-RAS have been developed
Previous Work
2 MAIN CONTRIBUTION
Main Results
Limitation and future development
De Rosa P. Q-RAS plugin

3. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
OUTLINE
1 MOTIVATION
Why Q-RAS have been developed
Previous Work
2 MAIN CONTRIBUTION
Main Results
Limitation and future development
De Rosa P. Q-RAS plugin

4. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
WHY Q-RAS?
WHY DEVELOP E TOOL TO PREPARE HEC-RAS GEOMETRY
RAS is a oods numerical model where the aim is to provide
an inundation maps starting from real data. A strong
correlation between GIS and RAS exist
The common RAS user is almost novice of GIS (usually an
hydraulic engineer)
The common RAS user use Win
Geometry data preparation in RAS is really time-consuming
specially when starting from real data | HEC-RAS
preprocessing
De Rosa P. Q-RAS plugin

5. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
WHY Q-RAS?
WHY DEVELOP E TOOL TO PREPARE HEC-RAS GEOMETRY
RAS is a oods numerical model where the aim is to provide
an inundation maps starting from real data. A strong
correlation between GIS and RAS exist
The common RAS user is almost novice of GIS (usually an
hydraulic engineer)
The common RAS user use Win
Geometry data preparation in RAS is really time-consuming
specially when starting from real data | HEC-RAS
preprocessing
De Rosa P. Q-RAS plugin

6. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
WHY Q-RAS?
WHY DEVELOP E TOOL TO PREPARE HEC-RAS GEOMETRY
RAS is a oods numerical model where the aim is to provide
an inundation maps starting from real data. A strong
correlation between GIS and RAS exist
The common RAS user is almost novice of GIS (usually an
hydraulic engineer)
The common RAS user use Win
Geometry data preparation in RAS is really time-consuming
specially when starting from real data | HEC-RAS
preprocessing
De Rosa P. Q-RAS plugin

7. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
WHY Q-RAS?
WHY DEVELOP E TOOL TO PREPARE HEC-RAS GEOMETRY
RAS is a oods numerical model where the aim is to provide
an inundation maps starting from real data. A strong
correlation between GIS and RAS exist
The common RAS user is almost novice of GIS (usually an
hydraulic engineer)
The common RAS user use Win
Geometry data preparation in RAS is really time-consuming
specially when starting from real data | HEC-RAS
preprocessing
De Rosa P. Q-RAS plugin

8. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
OUR SITUATION
We often have to spend time preparing geometry to run
hydraulic models.
the ratio is 60% in time preparing geometry 40% in run
simulation
Thanks to the high resolution DEM (LiDAR) geometry quality
can improve considerably
To prepare geometry a mix of Prole tools have to be applied
De Rosa P. Q-RAS plugin

9. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
OUR SITUATION
We often have to spend time preparing geometry to run
hydraulic models.
the ratio is 60% in time preparing geometry 40% in run
simulation
Thanks to the high resolution DEM (LiDAR) geometry quality
can improve considerably
To prepare geometry a mix of Prole tools have to be applied
De Rosa P. Q-RAS plugin

10. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
OUR SITUATION
We often have to spend time preparing geometry to run
hydraulic models.
the ratio is 60% in time preparing geometry 40% in run
simulation
Thanks to the high resolution DEM (LiDAR) geometry quality
can improve considerably
To prepare geometry a mix of Prole tools have to be applied
De Rosa P. Q-RAS plugin

11. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
OUTLINE
1 MOTIVATION
Why Q-RAS have been developed
Previous Work
2 MAIN CONTRIBUTION
Main Results
Limitation and future development
De Rosa P. Q-RAS plugin

12. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
STATE OF ART.
COMMERCIAL SOFTWARE
HEC-GeoRAS (ArcMAP extension)
Autocad Civil 3D
...
OPEN SOURCE SOFTWARE
GRASS module to prepare geometry
v.grass2hec v.hec2grass | 2008
grass-hecras toolkit |
https://github.com/micha-silver/grass-hecras
De Rosa P. Q-RAS plugin

13. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
STATE OF ART.
COMMERCIAL SOFTWARE
HEC-GeoRAS (ArcMAP extension)
Autocad Civil 3D
...
OPEN SOURCE SOFTWARE
GRASS module to prepare geometry
v.grass2hec v.hec2grass | 2008
grass-hecras toolkit |
https://github.com/micha-silver/grass-hecras
De Rosa P. Q-RAS plugin

14. Motivation
Main contribution
Discussion
why Q-RAS
Previous Work
V.GRASS2HEC V.HEC2GRASS PECULIARITY
PECULIARITY
They run under GRASS and Linux
A version for Win working under the GRASS toolbox have
been released
The works as Preprocessor/PostProcessor of RAS
The modules have been extensively widespread since 2008
De Rosa P. Q-RAS plugin

15. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
OUTLINE
1 MOTIVATION
Why Q-RAS have been developed
Previous Work
2 MAIN CONTRIBUTION
Main Results
Limitation and future development
De Rosa P. Q-RAS plugin

16. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS HOW TO WORK.
INPUT
High resolution DEM
river vector layer (digitized from Upstream to Downstream)
Cross Sections XS (digitized from left over bank to right over
bank)
OUTPUT
SF geometry le - The interchage geometry GIS data for RAS
De Rosa P. Q-RAS plugin

17. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS HOW TO WORK.
INPUT
High resolution DEM
river vector layer (digitized from Upstream to Downstream)
Cross Sections XS (digitized from left over bank to right over
bank)
OUTPUT
SF geometry le - The interchage geometry GIS data for RAS
De Rosa P. Q-RAS plugin

18. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS STEP BY STEP
FIGURE: The input data required. Note the mess order of XS.
De Rosa P. Q-RAS plugin

19. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS STEP BY STEP #2
FIGURE: How input data are passed to the plugin
De Rosa P. Q-RAS plugin

20. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS STEP BY STEP
FIGURE: The river and the cross section in QGIS.
De Rosa P. Q-RAS plugin

21. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS STEP BY STEP
FIGURE: The river with the same cross section imported in RAS
De Rosa P. Q-RAS plugin

22. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
OUTLINE
1 MOTIVATION
Why Q-RAS have been developed
Previous Work
2 MAIN CONTRIBUTION
Main Results
Limitation and future development
De Rosa P. Q-RAS plugin

23. Motivation
Main contribution
Discussion
Main Results
Limitation and future development
Q-RAS LIMITS/LACKS
A WISH-LIST OF FURTHER PROPRIETIES
MISSING GEOMETRY
FEATURES
Banks
Inline structures as Bridge
and culvert
blocked obstruction
ineective ow areas
RAS POSTPROCESSOR
import RAS output for
ood inundation map
follow the v.hec2grass
example
import data from RAS
mapper
(area limited to the XS
convex hull)
De Rosa P. Q-RAS plugin

24. Motivation
Main contribution
Discussion
DISCUSSION
OTHER SIMILAR TOOLS
Q-RAS is note the only plugin that link QGIS and RAS. Few
days after Q-RAS release riverGIS have been published. This
plugin works as RAS preprocessor creating 2D geometry.
RAS 2D is still in beta. It's not a real 2D model but ti is
promising riverGIS have a future
Craysh A collection of tools for TUFLOW and other hydraulic
modelling packages.
BASEmesh is a free tool for the generation of computational
meshes for the numerical software BASEMENT http:
//www.basement.ethz.ch/services/Tools/BASEmesh
De Rosa P. Q-RAS plugin

25. Appendix For Further Reading
FOR FURTHER READING I
Chiraz P. Ricci A. 2007
http://www.gitonline.eu/GITTMP/GIT2007/GIT_
Bevagna_2007/Lavori_GIT_2007_pdf/6-Presentazione_
Chiraz.pdf
Convegno GIT, 2007.
http://rivergis.com/
https:
//github.com/lutraconsulting/qgis-crayfish-plugin
De Rosa P. Q-RAS plugin

26. Appendix For Further Reading
FOR FURTHER READING II
Hinkelammert, F., Volz, C., Boes, R.M. (2012).
Einsatz eines freien Geoinformationssystems (GIS) für die
hydraulische 2D-Modellierung.
Symposium der Wasserbau-Institute TU München, TU Graz
und ETH Zürich, Graz, Austria.
Chiraz , P., Ricci , A. 2008
Veriche idrauliche: Processi di automazione ed
interoperabilità a livello dati tra GRASS ed HEC - RAS,
IX Meeting degli Utenti Italiani di GRASS GIS GFOSS ,
Perugia .
De Rosa P. Q-RAS plugin