Watershed delineation

Discussion created by fdm4 on May 27, 2011
Latest reply on Jun 14, 2011 by Lady_Jane
I am new to GIS and ARCHYDRO in particular but knowledeable in hydrology. I am trying to delineate watersheds for my area. I am using Arcmap 9.3.1 and ArChydro 1.3 . The main river is an outlet of a lake; from the main lake, it flows into another small lake and emerges again. I also have an inland drainage lake within the same study area. I have followed the steps in ArcHydro and have read for over 2 weeks but nothing come close. I am a student and am in an institution where no one has knowledge ArcHYDRO. Your consideration to assist will be greatly appreciated.

1. Do the lakes need special attention?

2. I came across literature which said stream lines should first b checked for features such as braiding, brokebn streams, open waterbody boundary and dangling nodes as these may cause errors. How does one remove these in ArcMAP/ARCHYDRO? I found out that my streams has breaks.

3. These problems aside, when i follow all the steps, some of the delineated rivers are discontinous at some points; yet the actual rivers are continous, how do i deal with this?

4. When i use river gauges as batch points, i get watershed (if one comes at all) that are tiny or localised around that area. From my hydrology knowledge, a watershed covers an entire area upstream of a particular point.

5. Is there a way to merge watersheds? I want to have Hydrology Response Units that are similar to what is on paper map, which was manually delineated by my country in the 80's

Thank you