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

Case Study: Grayling Stormwater Project
The Grayling Stormwater Project is an example of a hybrid project that
combines LID with end-of-pipe treatment. This project demonstrates that
a small community is capable of making the fundamental shift in management
towards LID and providing leadership for other communities to make
similar changes.
The measures taken will eliminate approximately 80 percent of the water
pollution from the city.
Typical Grayling Rain Garden, July 2007
Source: Huron Pines
This large-scale project includes 86 rain gardens along with installation of
an “end-of-the-pipe” detention basin and seven underground Vortechnic oilgrit
separator units. Several of the rain gardens that are smaller or that need
to accommodate higher volumes of water were installed with underdrains,
but most use the natural infiltration capacity of the area’s sandy soils.
Currently, all major outfalls of stormwater from the City of Grayling are being
treated by one or more of these measures. Future plans for the project include
a maintenance program with incentives for landowners who water and weed
their rain gardens, and an outreach program to educate the public and help other
communities voluntarily integrate LID into their stormwater management.
Project Type
Case Study Site Considerations
Protect sensitive/special value features, rain gardens/bioretention,
detention/extended detention, filters
(specifically oil-grease separators)
Soil Conditions Sandy and extremely well drained
Estimated Total
Project Cost
Maintenance
Responsibility
Project Contact
$1.2 million
City of Grayling – maintenance of Vortechnic Units,
Huron Pines – establishment of plants
Jennifer Muladore, 989-344-0753 ext 30,
Jennifer@huronpines.org
Lessons Learned
The rain gardens were planted
with seed and a few shrubs. The
seed did not grow well, most
likely due to the harsh cold
winters and hot, dry summers in
the Grayling area, where plants
take a lot longer to establish
in the extremely well-drained,
sandy soils.
Plants that thrive in dry soils
do need frequent watering to
survive (project contracted out
to a local landscaping company
for watering).
In addition, many of the
residents in the neighborhood
are not happy with the “wild”
seeded look and would rather
have had more manicured
gardens. In future phases, the
City of Grayling will plant fewer
gardens with larger plant stock
and try to locate them where
homeowners are more interested
in helping to maintain them.
LID Manual for Michigan – Chapter 7 Page 132