Geologic Vulnerability - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 202

• Source of potable water . If the aquifer encountered beneath a particular site is used
as a source of potable water or is connected to a source of potable water, the risk
increases.

Evaluating this parameter must also include other potential uses besides the provision of
drinking water. Further information may be necessary to identify those uses and accu-
rately score this parameter.

6.4 Map-Building Example
Because of its diversity, a good example of building a geologic vulnerability map is pro-
vided by the Rouge River watershed located in southeastern Michigan (Figure 6.1).
As noted in Section 1.2, several key features making the Rouge River watershed an ideal
watershed to study include

• It is an urban watershed
• It has varied geology and hydrogeology
• There are different stream patterns and densities throughout
• The population is high: approximately 1.5 million people
• The watershed has been studied extensively

St. Clair

Macomb

Oakland

Livingston

Rouge
watershed

Washtenaw

Wayne

Rouge River watershed

Monroe

Michigan

Rouge River watershed

FIGURE 6.1
Rouge River watershed.