Automated Watershed Delineation

[beej67]

A programmer friend and I have a pretty slick idea about how to write some software that automatically generates watershed boundaries off of raster data, then does the sub-delineations within the boundary for watershed characterization, then gives you peak event discharges for a study point based on Rational, NRCS, and USGS regression methods, through what would basically be a one-click interface. One click defines the watershed boundary, gives you weighted C, weighted CN, rational Q, NRCS peak Q, and USGS regression Q, if you have your starting watershed in the right raster format.

My question is whether someone's already done this, particularly the auto-watershed-boundary stuff.

I've seen a hydro package in AutoCAD LDD that was supposed to generate watershed boundaries off of a TIN, but it always came out like crap because of how it followed the triangles, and always had a lot of little islands and fudge all in the middle. It was basically worthless when I tried it. Does Civil3D have one that works?

I have very little experience with the ESRI softwares, and haven't seen their watershed tools yet. Do they have a package that can do this? I always suspected their watershed delineation tools would have same sorts of problems LDD did, because they're vector as well, but I don't really know for sure.

Does anyone else have something out like this?

Don't want to go reinventing the wheel.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[sam74]

Microstations and Geopak had a delineate watershed function. It didn't work very well though either. But of course software usually gets better with revisions.

 

[beej67]

I remember seeing a package in TerraModel in the late 90s that worked like crap too.

How about BASINS? Its documentation claims to do automated watershed characterization. Does it work?

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[francesca]

* Any automated watershed delimiter is going to be a function of the quality of the TIN/DEM.
* Purdue university has a watershed delimiter that gives you your CN and Q.

https://engineering.purdue.edu/mapserve/LTHIA7/index.html

 

[elev8848]

beej67:

ArcGIS spatial analyst watershed delineation tool is available as a Model. see esri script website. Pre or post processing can be automated in the model builder depending upon user's unique requirement. For example: we needed boundaries to follow certain criteria like do not cross a building polygon etc.

Civil 3D does somewhat decent job as well.

 

[froude]

I believe ArcHydro, which is a GIS add on, does delineations. But as francesca said, it all seems to depend on your input surface.

 

[Ryb01]

ArcHydro, will complete deliniations based on contour data.
For larger drainage areas we use it as a first cut of the boundaries, as with any model it's only as good as the information it has been provided.

You can also set up a data base with a little help from Microsoft Access to set up hydrologic soil groups based on soil type, land use and CN #'s, etc.

I believe there is a compont of ArcHydro which utilizes StreamStats (USGS) for several states. By clicking on a point of interest it will show the drainage areas and flows from the USGS website. Not sure hjow many states are on board though.

 

[TerryScan]

I use Carlson Civil add-on for Autocad. It does automatic watershed delineation of tins or grids.

As fransesca pointed out, the result will be largely dependant on the input data. beej67 mentioned raster data as input. We do not yet know specifically what kind of raster data he is using. If it is 30m DEM data for example, I'm sure it won't have "a lot of little islands and fudge all in the middle" because it won't be as detailed as a typical site ground survey. The surface would be smoothed in comparison. While the watersheds may "look" better, the evaluation may miss subtle surface features (which may or may not be relevant).

I work mainly in a coastal plain where topo is quite flat. This "multitude of tiny areas" phenomenon is very pronounced.

I really liked the watershed evaluation in PacSoft (an older, now defunct software). However, Carlson Civil does have the option to input a rainfall depth which should combine small depressions as they "spill" into the next area (I preferred PacSoft's depth of depression criteria to the rainfall depth option).

Of course, if one can "build a better mousetrap", there will always be a market.

 

[beej67]

Derail:

Do you like Carlson Civil? I looked at that when I was IntelliCAD shopping. What's a license run, and is it worth it? I may eventually have to break down and buy something that can do civil storm pipe newtorks like StormCAD does, but haven't earmarked the cash for it yet. If I do, I wouldn't mind picking up some CAD and drafting functionality at the same time. Does Carlson handle pipe networks and pipe profiles well?



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[francesca]

beej67 Civil 3D can do all of that. It is also a GIS interface, has a SWMM module and a HEC-RAS export tool.

 

[beej67]

But do they work?

The last time I fooled with hydraulics in Autocad Land Development Desktop they were nothing more than the old Softdesk routines shoehorned in with all the same bugs. It'd go haywire the moment you had more than one branch in your pipe network. What's the SWMM module like? Is it as robust as EPA-SWMM or XP-SWMM?

I've tried several times in my career to utilize hydraulics and hydrology tools within AutoCAD, and every time I've found them suspect at best. You certainly seem to know your stuff here on eng-tips though, francesca, so if you vouch for them I might give Civil3D another look. I always make a point of reading your posts.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[Trackfiend]

francesca is right. Civil 3d has come a long way from Land Development Desktop. When I first started working in civil design, I used EPA's SWMM 5.0, Hydraflow's Hydrographs, and various other excel worksheets that I developed as a backcheck to whatever methodology I was using (Rational, SCS, etc.). Since then, Autodesk has consumed the competition by buying out Intelisolve (the makers of Hydraflow software) and some portions of Boss International which produced the StormNET software (which is basically a pretty dress on the SWMM engine). Now both the Hydragraphs (and other Intelisolve products) and StormNET are part of the Civil 3D package. I've been using the new Storm and Sanitary Analysis add-on for about a month now and have been going back and forth with comparisons to EPA's SWMM on some older projects. So far so good. Autodesk's software documentation and user manuals are fairly superior to other products in my opinion, but I've also only been playing around with these products for 4-5 years so my experience is fairly limiited.

Now if I could just get this Storm and Sanitary Analysis program to model trench drains correctly......

 

[beej67]

Hydraflow Hydrographs may be my least favorite software, largely because of how "user friendly" it is. I've peer reviewed more hydrology studies done blatantly wrong with that thing than were done right. It allows engineers without an adequate background in hydrology to break all sorts of rules, and makes them think they know what they're doing. Plus it's streamlined in such a way that it almost encourages rule bending. Also, no accounting whatsoever for variable tailwater. Ugh. One of the worst things you can do as a developer of engineering software is convince an inexperienced engineer something's right when it's not.

If Civil3D's version of the SWMM engine is good, though, then it might be worth looking into. Is there a node limit? Can you run multiple storms in the same pass? I've been an XP-SWMM user for years, as a point of comparison.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[SMIAH]

I'm not a fan of Automated Watershed Delineation. Using it as a start when the watershed is large. But then, manually edit it to take in account the presence of roads and culverts or else man-made structure.

And USGS.

http://water.usgs.gov/osw/streamstats/index.html

 

[Ryb01]

SMIAH.......definitely agreed!

 

[TerryScan]

beej67-

Carlson Civil does have pipe networks in the hydrology module. I used to use Stormcad but now use Carlson for this.


I believe one can get a demo copy if you want to check it out. From their website, it appears one can get the Civil Suite package for $2500.

http://www.carlsonsw.com

 

[francesca]

Autodesk outsources all of its training, so gives a load of stuff away. The student site is an amazing resource and the tutorials on the main site, not to mention the 17 MB pdf user guide are comprehensive. Bentley, on the other hand, keeps its training in-house and you're lucky if you can find a half-decent webinar for free.

Autodesk has 30-day free trials on their website. Be warned, though. Civil 3D is the entire circus, even if you only want the clowns. It's a 4 GB download and doesn't do anything complicated without crashing a lot on Win XP, especially with less than 2 GB of RAM. I have found that 2011 is a lot more stable, though.

 

[Trackfiend]

"If Civil3D's version of the SWMM engine is good, though, then it might be worth looking into. Is there a node limit? Can you run multiple storms in the same pass? I've been an XP-SWMM user for years, as a point of comparison."

Currently there is no node limit with the new Storm and Sanitary Analysis add-on for Civil 3D and yes you can run a batch analysis (multiple storm events) at once (under the Analysis Options tab). What I'm still trying to figure out is how to present the solution results from the multiple storm analysis side by side, both graphically and in report.

It is a shame though, as francesca pointed out, that this program is only attainable by purchasing Civil 3D, of which you probably will only use 30% of the what Civil 3D is really capable of (and it is quite pricey as well).

 

[beej67]

You can't export data to a text output file? It won't draw hydrographs or whatnot for you in a CAD environment? What's the data presentation like for the thing?

For years I've been outputting SWMM stuff into a comma delimited text file, and dumping it into pregenned Excel templates that auto-update with the new data. I figured at a minimum the same approach would work with Civil3d, and expected that (better) it'd just draw the dang graphs for you in CAD so you can manipulate them even easier.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[darctones]

What's your idea?

I've read a few interesting articles on new ways to interpret TINs for more accurate contouring and delineation.