Low Impact Development Manual for Michigan - OSEH - University ...

Protection of sensitive areas in residential development in
Washington Township, MI
Preserving open space in multiple development areas
throughout a community can ultimately evolve to
form a unified open space system, integrating important
conservation areas throughout the municipality
and beyond. Many communities within Michigan are
undertaking “green infrastructure” planning initiatives
to proactively map these systems in order to restore or
protect them as development occurs. The objective of
these plans is to avoid impacting sensitive areas by:
1) carefully identifying and mapping these resources
(resource areas, primary and secondary) from the start
of the site planning process, and 2) striving to protect
resource areas by defining other portions of the site free
of these resources (potential development areas).
At the community level, local governments can implement
community-wide regulations that protect sensitive
areas such as wetlands, woodlands, riparian areas, and
floodplains. Appendix H contains model ordinances for
various sensitive resources developed for communities
in Michigan.
Potential Applications
Regardless of land use type, protecting sensitive areas
is applicable across all types of land development projects,
whether residential of varying densities or office
park, retail center or industrial and institutional uses. As
density and intensity of uses increases, ease of application
of this BMP decreases. In such limited cases, it is
especially important that sensitive areas be prioritized.
Environmentally Sensitive
Resources
SEMCOG has analyzed possible impacts on environmentally
sensitive resources from planned transportation
projects in Southeast Michigan, which may
be helpful in minimizing site disturbance in certain
development areas.
SEMCOG has defined these environmentally sensitive
resources and potential impacts of planned transportation
projects in the document, Integrating Environmental
Issues in the Transportation Planning Process:
Guidelines for Road and Transit Agencies.
The transportation projects were identified from the
2030 Regional Transportation Plan for Southeast
Michigan (RTP) and were mapped using Geographic
Information Systems (GIS).
Please visit www.semcog.org to download maps of
the sensitive resources in PDF or to download data in
GIS format.
Design Considerations
1. Identify, map, and inventory sensitive areas.
Mapping a site’s sensitive areas is an important
step in preserving them (Figure 6.4). These
features often include wetlands, steep slopes,
woodlands, floodplains, and riparian areas. These
data may give the community a general idea of
the sensitive resources that could be on the site. In
addition, the mapping will help the site designer
define a potential development area which avoids
encroachment upon and disturbance of defined and
mapped sensitive areas.
The inventory of sensitive areas should also include
an assessment of the quality of the existing natural
communities. Because plant communities will exist
in a variety of states based on historic disturbance
and degradation, the quality of the given
community needs to be considered in comparison to
other similar communities. For instance, two upland
forests in adjacent parcels may have significantly
differing floristic quality, thus influencing the
selection of land for site development. A floristic
quality inventory (FQI) may be used to quantify the
quality of a given natural community. As a general
LID Manual for Michigan – Chapter 6 Page 100