Watershed Investigations Are a Crucial First Step in Watershed Restoration Planning

When a lake has problems, it is important to look beyond the algae scum and determine the underlying source(s) of the problem. A good first step is to perform watershed investigations, also known as watershed inventories, to identify nonpoint sources of pollution. 

Watershed investigations can be used to detect stormwater management opportunities, streambank erosion problems, riparian buffer restoration opportunities, agricultural BMP implementation sites, invasive species infestations, and other potential sources of water quality problems. Inventories are often done by volunteers under the direction and training of a lake manager or other water quality professional. Soliciting input from watershed residents is critical since "the locals" often know about problem areas that exist on private property or that are otherwise not easily discerned in a roadside survey. County Conservation Districts and other local agencies can also be helpful in identifying potential problem areas

Lake Wallenpaupack Watershed Problem Area Map

Watershed investigations are usually performed by traveling throughout the watershed with a GPS receiver, a camera, a good-quality watershed map, and a set of data forms. Areas of excessive stormwater runoff and soil erosion are documented for all existing land uses including commercial, residential, institutional, public, industrial, and agricultural. Areas to be investigated should include roadway stream crossings, streambanks, shorelines, farms, culverts, ditches, storm drainage outfalls, and parking lots. Once a problem area is identified, the coordinates are marked using the GPS reciever so that the location can be found again and so the sites can be incorporated into a Geographic Information Systems (GIS) map. Photos of the area are helpful, as are measurements of any eroded areas for restoration planning purposes and cost estimates. Typically, a sketch of the problem area is included on the data sheet. Because the usefulness of the watershed inventory data is only as good as the quality of the information gathered, proper training of any volunteers is critical.

In developed areas, stormwater management should primarily focus on retrofitting existing stormwater facilities or adding new stormwater facilities. Therefore, both existing stormwater facilities and large impervious surfaces in need of stormwater management practices should be included in the investigations. In such areas, investigations should be performed by a stormwater management professional due to the more technical nature of the locations. 

Once the watershed investigations are complete, the data are entered into a spreadsheet and analyzed. Potential BMPs and restoration alternatives are determined for each site and cost estimates are developed, if possible. Problem areas can then be prioritized based on cost, severity, and likelihood of restoration success. At this point, the watershed group has a plan of action with which to go forward and pursue funding for lake and watershed restoration measures.

For an example of an organization that has performed watershed investigations and used the results to successfully implement watershed BMPs, please visit the Lake Wallenpaupack Watershed Management District website at http://www.wallenpaupackwatershed.org/html/descript/bmp-index.html. The site includes GIS maps and a list of both problem areas and BMPs, including photos, descriptions, and costs.

F. X. Browne, Inc. conducts watershed inventories, GIS mapping, and watershed restoration measures for all sizes of watersheds. Please contact us at info@fxbrowne.com or 215-362-3878 for more information.