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SECTION 4 – DESCRIPTION OF EXISTING ENVIRONMENT IN PLANNING AREA
4-7
TABLE 4-2
Planning Area Detailed Existing Land Use
Land Use Type
Square Miles
Percent of
Planning
Area
Estimated
Percent
Impervious
4
Estimated
Impervious
Square Miles
Commercial
0.6
6%
82%
0.5
Industrial
1.0
10%
82%
0.8
Office and Institutional
1.0
10%
72%
0.7
Mixed Use
1
0.2
2%
72%
1.1
Transportation
2
1.2
13%
87%
0.6
High-density Residential
0.8
8%
72%
0.3
Medium-density Residential
0.7
8%
44%
0.3
Low-density Residential
1.4
14%
21%
0.1
Undeveloped/Vacant
3
1.9
19%
4%
<0.1
Golf Course
0.3
3%
4%
<0.1
Park/Greenway/Open Space
0.7
7%
4%
0.5
Total
9.8
100%
4.5
Sources: Town of Morrisville, 2013
Note: The Town’s land use categories are described in Appendix D
1
Mixed use was categorized within the non-residential developed category in Table 4-1.
2
Transportation is not included in the land use coverages. The area used for transportation was
estimated by subtracting the land use area from the transportation area.
3
Undeveloped land is forested or vacant lots. The Town does not have any active farms.
4
Percent imperviousness estimates are based on a modeling analysis done for the Town of Cary (CH2M
HILL, 2002a). Imperviousness values most likely over-estimate the percent imperviousness because
reference categories contained slightly higher densities for residential classes than the Town of Morrisville
designates.
Table 4-2 also includes estimates of percent imperviousness; the estimated values shown in
the table were used in modeling analyses performed for the Town of Cary in its Northwest
Area (CH2M HILL, 2002a). These values are based on literature values. The percentage
impervious per land class was used to estimate the impervious area for the 2013 land use
data. These were then summed and divided by the total land area to estimate the overall
impervious value for existing land use conditions. The total estimated percent impervious is
approximately 45 percent.
4.4
Wetlands
For regulatory purposes under the Clean Water Act (CWA), the term wetlands means
“those areas that are inundated or saturated by surface water or groundwater at a frequency
and duration sufficient to support, and that under normal circumstances do support, a
prevalence of vegetation typically adapted for life in saturated soil conditions.” In general,
wetlands share three key characteristics: wetland hydrology, hydric soils, and hydrophytic
vegetation. Wetlands and vegetated riparian areas are valuable because they are among the