[GRASS-user] r.watershed

[Shane Carey]

I just used the tutorials from this page
https://grasswiki.osgeo.org/wiki/Creating_watersheds to extract the stream
network - however it could be more accurate so was wondering is r.terraflow
a better option for me. I was using r.watershed originally

Do you know why sink filling is needed for r.terraflow and not for
r.watershed?

Thanks.

On Wed, Dec 6, 2017 at 11:42 AM, Marco Alicera <marco.alicera at gmail.com>
wrote:

> How did you add culverts?!
> Such a great question and I also wonder how you did. Short ago I knew
> about Itzï and its ability to do it with SWMM
> http://itzi.readthedocs.io/en/latest/tutorial.html#culvert-modelling.
> Looking forward to testing it
> --
> Marco
>
> 2017-12-06 9:24 GMT+01:00 Shane Carey <careyshan at gmail.com>:
>
>> Hi Mark,
>>
>> Thanks for your reply! Sounds great.
>> How did you add culverts or other artificial flow control features to
>> achieve water flowing through roads?
>>
>> I have a rivers layer and I compared it the streams I've obtained from
>> r.watershed and r.watershed appears to not match these streams (which were
>> accurately digitised) and I was wondering if I had a better resolution DTM
>> would it solve this problem?
>>
>> Also, why is sink filling needed for terraflow and not watershed?
>>
>> Thanks for your help :-)
>>
>> On Máirt 5 Noll 2017 at 23:43, Mark Seibel <mseibel at gmail.com> wrote:
>>
>>> Hi Shane.
>>>
>>> I'm happy to report that I've modeled overland water flow with
>>> r.watershed for over a quarter million acres, consisting of several large
>>> project sites, at 1 meter DEM resolution. The data source was LiDAR
>>> points to make the DEMs.
>>>
>>> At this resolution, it becomes necessary to add culverts, or other
>>> artificial flow control features, to achieve water flowing through a road.
>>> Otherwise, water is routed along roads until a lowest point is reached for
>>> crossing.
>>>
>>> I also use r.terraflow outputs as ancillary data to help drop in culvert
>>> locations and help provide guidance in problem areas.
>>>
>>> My geographic area is central Florida, which is very flat and full of
>>> topographic depressions known as wetlands. These depressions interrupt the
>>> stream network continuity in reality, but r.watershed does a fantastic job
>>> making a continuous drainage network model, especially in these difficult
>>> areas.
>>>
>>> Happy Modeling!
>>>
>>> Mark
>>>
>>> On Tue, Dec 5, 2017, 3:49 PM Shane Carey <careyshan at gmail.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I am trying to extract river network from a 5m DEM with some success
>>>> using r.watershed. Has anyone tested this algorithm on high resolution
>>>> LiDAR data for example - 1meter DTM and what kind of results have they
>>>> obtained?
>>>>
>>>> Thanks
>>>>
>>>> --
>>>> Le gach dea ghui,
>>>> *Shane Carey*
>>>> *GIS and Data Solutions Consultant*
>>>>
>>> _______________________________________________
>>>> grass-user mailing list
>>>> grass-user at lists.osgeo.org
>>>> https://lists.osgeo.org/mailman/listinfo/grass-user
>>>
>>> --
>> Le gach dea ghui,
>> *Shane Carey*
>> *GIS and Data Solutions Consultant*
>>
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/grass-user
>>
>
>


-- 
Le gach dea ghui,
*Shane Carey*
*GIS and Data Solutions Consultant*
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