Abily Morgan Work on Abily Morgan Work on ARC GIS for Hydroasia ARC GIS for Hydroasia 20092009

The Aim of this PPT file is to present The Aim of this PPT file is to present my work during the last two weeks my work during the last two weeks concerning Incheon Gyo watershed, concerning Incheon Gyo watershed, using Arc GIS toolusing Arc GIS tool

My work had consisted in using Arc My work had consisted in using Arc GIS tool to build a DEM and to GIS tool to build a DEM and to delimited the sub-catchment in the delimited the sub-catchment in the studied area. studied area.

PlanPlan

1 – Create a DEM1 – Create a DEM Create a Tin of the catchment areaCreate a Tin of the catchment area Create a raster of the catchment Create a raster of the catchment

areaarea

2 - Definite the sub-catchments of the 2 - Definite the sub-catchments of the watershedwatershed

3 - Recommendation and work for the 3 - Recommendation and work for the next weeknext week

1 - Create a DEM1 - Create a DEM

Create a Tin of the Create a Tin of the catchment areacatchment area First it is needed to clip two layers First it is needed to clip two layers

to create the tin and then,to to create the tin and then,to create the raster and the DEMcreate the raster and the DEM

I had cliped the layer: catchment I had cliped the layer: catchment and the layer: contour and the layer: contour

To do so I had use the tool called To do so I had use the tool called clip in the Arctoolboxclip in the Arctoolbox

Create a Tin of the Create a Tin of the catchment areacatchment area Then to create the Tin, use 3D Then to create the Tin, use 3D

analysis extension like follow:analysis extension like follow:

Create a Tin of the Create a Tin of the catchment areacatchment area Then create the Tin like follow: Then create the Tin like follow:

use 3D analysisuse 3D analysis Select the manhole layerSelect the manhole layerSelect the previously constructed Select the previously constructed

cliped layer cliped layer Thoses two layers are selected Thoses two layers are selected

because you can use their because you can use their elevation propertyelevation property

Create a raster of the Create a raster of the catchment areacatchment area It is now needed to convert the It is now needed to convert the

tin into a raster:tin into a raster:

Create a raster of the Create a raster of the catchment areacatchment area I have proceed as you can see in I have proceed as you can see in

this slide.this slide.

Then the DEM is createdThen the DEM is created

2 - Definite the sub -2 - Definite the sub -catchments of the catchments of the watershedwatershed

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed First it is needed to use Arc-hydro toolsFirst it is needed to use Arc-hydro tools The interesting part of this extension is The interesting part of this extension is

called “Terrain processing” inside it, called “Terrain processing” inside it, you have a huge set of tools.you have a huge set of tools.

Briefly this is how to proceed: click onBriefly this is how to proceed: click on

DEM manipulation, fill sinkDEM manipulation, fill sink

Then Flow directionThen Flow direction

… …

After this you can use: flow After this you can use: flow accumulation, steam definition, accumulation, steam definition, steam segmentation and finally, steam segmentation and finally, using drainage line process, this is using drainage line process, this is what you can get:what you can get:

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed

The following step is to use the the The following step is to use the the tools, still in terrain processing part tools, still in terrain processing part in the Arc hydrotools:in the Arc hydrotools:

Catchment grid and catchment Catchment grid and catchment polygonepolygone

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed

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

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed

Drainage points:Drainage points:

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed

Provisory Sub-catchment:Provisory Sub-catchment:

Definite the sub-Definite the sub-catchments of the catchments of the watershedwatershed

Recommendation and Recommendation and work for the next week:work for the next week: The sub-catchments definitin have to The sub-catchments definitin have to

be ameliorated by a better drainage be ameliorated by a better drainage point selection and the boundary of point selection and the boundary of the catchment in not good and have the catchment in not good and have to be corrected.to be corrected.

This will be effectuated for the next This will be effectuated for the next weekweek

Think about the possibility to Think about the possibility to integrate the building layer in the integrate the building layer in the DEMDEM

3 - Recommendation 3 - Recommendation and work for the next and work for the next weekweek

Thank you for your Thank you for your attentionattention