Riparian Buffer Classification

 

Stream Outline

 

In ArcCatalog select File à New àShapefile. Name the shapefile, which will be used for outlining stream banks. In the feature type drop down menu select Polyline. Make sure to project in the appropriate coordinate system.

 

In ArcView 9.0 add the new shapefile to your ArcMap project. Start editing. When asked which folder you want to edit, select the one with your new shapefile and click OK. From your editor tool bar select the pencil and use it to outline both sides of all the streams that need to be classified.

 

Buffering the Streams

 

Once the streams are outlined you will create a 25 ft. and a 100 ft. buffer around the stream to facilitate visual assessment of the riparian width and adequacy. Open the Toolbox and click on the box next to Analysis Tools. Click on the box next to Proximity and chose the Buffer tool. The input feature class will be the stream outline shapefile. The output feature class will fill in on its own. Make the linear unit 25 ft. Create another buffer with a 100 ft. linear unit. You will have to hollow out the buffer.

 

Classifying the Riparian Zone

 

In order to create the database needed for the riparian classification, add a field to the stream outline attribute table that will eventually contain the riparian classifications (adequate, marginal, inadequate, and intermittent).

 

In the attribute table for the stream outline, click the Options button and then select add field. Create a name for the attribute (i.e. Riparian). From the Type drop-down menu select text and chose a length according to the amount of letters you will need for the attribute names.

 

To create the geodatabase go to ArcCatalog and select Fileà Newà Personal Geodatabase. Then right-click on the stream outline shapefile and select ExportàTo Geodatabase (single). In the Feature Class to Feature Class browse to the new geodatabase and select it for your output location. Use the new attribute field name as the Output Feature Class Name. You don’t need to fill in the rest.

Go back to the geodatabase and right-click to select properties. Select the Domain tab. Under the Domain Name type the attribute name (i.e. Riparian), and include a short description in the box on the right. In the Domain Properties Field Type write text. Domain Type will be Coded Values. Split Policy and Merge Policy can be left on default value. In Coded Values type the classification names in the Code boxes (Adequate_riparian, Marginal_riparian, etc.) In the Description box type the same exact text you typed in the code boxes.

Next double click on the Geodatabase, then right click on your new personal geodatabase. In the Feature Class Properties under Field Name, click the box with attribute field name (i.e. Riparian) this will change the Field Properties table below. In Field Properties write the attribute name in the box next to Alias. Allow Null Vales should say ‘no’. Leave the Default Value blank. Make sure the Domain displays the attribute field name (i.e. Riparian).

 

Classifying the Riparian Buffer

 

In the ArcMap project add the new geodatabase. Start Editing. Select one side of a stream outline and highlight it. Select the trace button on the editor tool bar. It may be helpful to change the selectable layers only to the themes on which you will be working. Trace the stream outline as long as the riparian classification remains the same (refer to the Riparian Classification Matrix) and then double click when a new class starts.

Select the attribute table icon on the editor toolbar and an attribute table will pop up. Next to the line that displays the attribute field you are classifying (i.e. Riparian) you can either type the first letter of the riparian classification you traced or choose it from the drop-down menu.

To classify the next riparian segment, click on the stream outline again and start over. It is very helpful to turn on your snapping to ensure the end of the lines are attached. It is also helpful to turn off the box next to the stream outline layer after you’ve highlighted it so that you can see where the previous classification line ended.