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

Floodplains
• Design the project to maintain natural drainage
patterns and runoff rates if possible.
• Maintain as much riparian vegetation as possible. If
riparian vegetation is damaged or removed during
construction, replace with native species.
• Use bioengineering techniques to stabilize stream
banks.
• Keep construction activity away from wildlife
crossings and corridors.
• Stockpile materials outside of the floodplain and
use erosion control techniques.
Woodlands
• Protect trees on sites with severe design limitations,
such as steep slopes and highly erodible soils.
• Preserve trees along watercourses to prevent bank
erosion, decreased stream temperatures, and to
protect aquatic life.
• Protect the critical root zone of trees during
construction. This is the area directly beneath a
tree’s entire canopy. For every inch of diameter
of the trunk, protect 1.5 feet of area away from
the trunk.
Critical root zone
Source: City of Falls Church, VA. Tree Preservation during
Construction.
• Avoid trenching utilities through the tree’s critical
root zone.
• Avoid piling excavated soil around any tree.
• Replace trees removed during construction with
native trees.
• Conduct post-construction monitoring to ensure trees
impacted by construction receive appropriate care.
General construction considerations
• Conduct a pre-construction meeting with
local community officials, contractors, and
subcontractors to discuss natural resource
protection. Communicate agreed-upon goals to
everyone working on the project.
• Insert special requirements addressing sensitive
natural areas into plans, specifications, and
estimates provided to construction contractors.
Note the kinds of activities that are not allowed in
sensitive areas.
• Confine construction and staging areas to
the smallest necessary and clearly mark area
boundaries. Confine all construction activity and
storage of materials to designated areas.
• Install construction flagging or fencing around
sensitive areas to prevent encroachment.
• Excavate only what is absolutely necessary to meet
engineering requirements. Do not put excavated
material in sensitive areas. (Excavated material
could be used in other areas of the site to improve
seeding success.)
• Conduct onsite monitoring during construction to
ensure sensitive areas are protected as planned.
Conduct post-construction monitoring to ensure
sensitive areas that were impacted by construction
receive appropriate care.
Maintenance
The preservation of open space creates maintenance
concerns related to who is required to perform the
maintenance activities. Legally, the designated open
space may be conveyed to the municipality. More
likely, ownership of these natural areas will be assumed
by homeowners’ associations or simply the specific
individual property homeowners where these resources
are located. Specific maintenance activities will depend
upon the type of vegetation present in the preserved
natural area where woodlands require little to no maintenance
and open lawn require higher maintenance.
LID Manual for Michigan – Chapter 6 Page 104