Abily Morgan Work on ARC GIS for Hydroasia 2009  The Aim of this PPT file is to present my work during the last two weeks concerning Incheon Gyo watershed, using Arc GIS tool  My work had consisted in using Arc GIS tool to build a DEM and to delimited the sub-catchment in the studied area.

Plan 1 – Create a DEM Create a Tin of the catchment area Create a Tin of the catchment area Create a raster of the catchment area Create a raster of the catchment area 2 - Definite the sub-catchments of the watershed 3 - Recommendation and work for the next week

1 - Create a DEM

Create a Tin of the catchment area First it is needed to clip two layers to create the tin and then,to create the raster and the DEM First it is needed to clip two layers to create the tin and then,to create the raster and the DEM I had cliped the layer: catchment and the layer: contour I had cliped the layer: catchment and the layer: contour To do so I had use the tool called clip in the Arctoolbox To do so I had use the tool called clip in the Arctoolbox

Create a Tin of the catchment area Then to create the Tin, use 3D analysis extension like follow: Then to create the Tin, use 3D analysis extension like follow:

Create a Tin of the catchment area  Then create the Tin like follow: use 3D analysis  Select the manhole layer  Select the previously constructed cliped layer  Thoses two layers are selected because you can use their elevation property

Create a raster of the catchment area It is now needed to convert the tin into a raster: It is now needed to convert the tin into a raster:

Create a raster of the catchment area I have proceed as you can see in this slide. I have proceed as you can see in this slide. Then the DEM is created Then the DEM is created

2 - Definite the sub -catchments of the watershed

Definite the sub-catchments of the watershed First it is needed to use Arc-hydro tools First it is needed to use Arc-hydro tools The interesting part of this extension is called “Terrain processing” inside it, you have a huge set of tools. The interesting part of this extension is called “Terrain processing” inside it, you have a huge set of tools. Briefly this is how to proceed: click on Briefly this is how to proceed: click on  DEM manipulation, fill sink  DEM manipulation, fill sink  Then Flow direction  Then Flow direction…

 After this you can use: flow accumulation, steam definition, steam segmentation and finally, using drainage line process, this is what you can get:  After this you can use: flow accumulation, steam definition, steam segmentation and finally, using drainage line process, this is what you can get: Definite the sub-catchments of the watershed

The following step is to use the the tools, still in terrain processing part in the Arc hydrotools: The following step is to use the the tools, still in terrain processing part in the Arc hydrotools:  Catchment grid and catchment polygone Definite the sub-catchments of the watershed

To finish, you have to use Drainage point processing, after that it is needed to selecte the point that seems interesting to you in order to determine, using the watersheld tool in the arc tool box the differents sub-catchment. To finish, you have to use Drainage point processing, after that it is needed to selecte the point that seems interesting to you in order to determine, using the watersheld tool in the arc tool box the differents sub-catchment. Definite the sub-catchments of the watershed

Drainage points: Definite the sub-catchments of the watershed

Provisory Sub-catchment: Definite the sub-catchments of the watershed

Recommendation and work for the next week:  The sub-catchments definitin have to be ameliorated by a better drainage point selection and the boundary of the catchment in not good and have to be corrected.  This will be effectuated for the next week  Think about the possibility to integrate the building layer in the DEM

3 - Recommendation and work for the next week

Thank you for your attention