How to define/delimit/outline a drainage basin. (step 1)
Note: This exercise draws a portion of a drainage divide. When you draw a divide it will make a complete circuit around the drainage basin.
The first step is to define the point where the river leaves the basin. The point can be placed anywhere along the river and the subsequent basin will include the entire area upstream from that point. Typically the point is placed near where the river being studied intersects with another river. (For this exercise, the point has been marked with a star near the place where Deer Creek enters the Mississippi River.)
Next step: Defining the primary drainage.
note: This exercise was completed as part of the Summer 2000 GIS Access workshop funded by the National Science Foundation. Images were generated using ESRI, Inc., ArcView 3.2.