[GRASS-user] r.watershed

[Shane Carey]

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