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

3. Analyze site’s vegetative features
Existing vegetation at the restoration site should
be examined to determine the overall strategy for
buffer protection and establishment. Strategies
will differ whether pre-restoration conditions
are pasture, overgrown abandoned field, midsuccession
forest, predominantly invasive
vegetation, or another type of setting. An effort to
inventory existing vegetation for protection and to
determine type of presettlement vegetation should
be made to guide efforts.
• Identify desirable species: Native tree and
shrub species that thrive in riparian habitats in
Michigan should be used. These species should
be identified in the restoration site and protected.
Several native vines and shrubs can provide
an effective ground cover when establishing
the buffer, though they should be controlled to
prevent herbaceous competition.
• Identify non-native and invasive species:
Consider using undesirable species for shading
during buffer establishment. Control invasive
plants prior to buffer planting may be necessary.
• Identify sensitive species: Because riparian zones
are rich in wildlife habitat and wetland plant
species, be aware of any rare, threatened, or
endangered plant or animal species. Be sure to
protect sensitive species during riparian buffer
restoration.
4. Map the site
Prepare an existing conditions sketch of the site
noting important features such as stream width,
length, stream bank condition, adjacent land uses,
stream activities, desired width of buffer, discharge
pipes, obstructions, etc.
5. Create a design that accomplishes multiple
stakeholder objectives
Ideally, the three-zone system should be
incorporated into the design to meet landowner,
community, and watershed objectives:
• Landowner objectives: Consider the current
use of the buffer by the landowner, especially
if the buffer will be protected by the landowner
in perpetuity. How will the riparian buffer
complement or conflict with existing and
probable future uses of the property?
• Community objectives: Consider linking
the buffer to an existing or planned green
infrastructure system, which may include trails,
parks, preserves, and wildlife habitat buffers.
How can a buffer help achieve local recreation
and green space goals?
• Watershed objectives: Examine the local
watershed plan to identify goals related to
riparian buffers. Have goals related to water
quality been emphasized. Is wildlife habitat a
primary concern?
6. Design measures
The following elements represent a menu of
design measures for riparian and natural resource
protection that communities may choose to
encourage or require developers to incorporate
during the site plan review process.
• Stream size – A majority of Michigan’s statewide
stream system is comprised of small streams
(first, second, and third order). It is important to
reduce nutrient inputs to these streams.
• Availability of areas for continuous buffers –
Establishing continuous riparian buffers on
the landscape should be given a priority over
establishing fragmented buffers. Continuous
buffers provide better shading and water quality
protection as well as buffers for the wildlife
movement.
• Degrees of degradation – Urban streams
have often been buried or piped as a result of
previous development. Streams in areas without
forestation may benefit the most from buffer
restoration.
• Loading rates - The potential for removing
pollutants is generally highest where nutrient
and sediment loading are the highest.
• Land uses – Land uses adjacent to the riparian
buffer may influence the required buffer width
and vegetation types. While the three-zone
riparian buffers described herein are ideal, the
full widths of each zone may not always be
feasible to establish, especially in urban areas.
• Habitats – Establishing a buffer for habitat
enhancement requires additional strategies
beyond installing a buffer for increased water
quality.
LID Manual for Michigan – Chapter 7 Page 272