Crabtree Swamp Rock Weir
Horry County Stormwater installed a low-head rock weir in Crabtree Swamp for the purpose of
controlling channel and bank erosion. The project is permitted by the US Army Corps of Engineers
and used a design prepared by the US Department of Agriculture's Natural Resources Conservation
Service. If the project is a success, additional weirs will likely be installed. The upper reaches
of Crabtree Swamp are experiencing significant bank and channel erosion. The weir is designed to
slow the water down and collect sediment in an attempt to build up the channel bottom. The weir
was placed just downstream from a small bridge in hopes of arresting the undercutting that was
occurring there.
South Strand Recreation Center Floating Wetlands
Horry County Parks and Recreation
needed a way to control algae fed by fertilizer at the new South Strand Recreation Center
ballfields. Horry County Stormwater contracted
Charleston Aquatic Nurseries to
install
floating wetlands
to compete for nutrients with the algae. The
Coastal Waccamaw Stormwater Education Consortium
turned the event into a demonstration drop-in for HOAs and residents and provided an information
booth.
Floating wetlands
are an alternative algae control method suited to neighborhood stormwater ponds.
Carolina Forest Recreation Center Constructed Wetland
Horry County Stormwater created a constructed stormwater wetland at Carolina Forest Recreation
Center in spring 2012. Students and teachers from
Ocean Bay Middle School
Science Club helped by removing invasive cattails and planting native aquatic and wetland plants
(
selected planting photos courtesy of The Sun News). The Science Club plans to monitor
the progress of the wetland and its effectiveness in removing pollutants from stormwater runoff
and providing wildlife habitat for native animals. The activity was co-sponsored by the
Coastal Waccamaw Stormwater Education Consortium.
Since that time, the constructed wetland has been featured as a demonstration site in Low Impact
Development workshops for professionals.
Administration Building Rain Garden Retrofit
In Fall 2010, Horry County Stormwater undertook a project to retrofit a failing dry detention pond
at the main administration building in Conway. The pond had become a nuisance, with ponding in the
bottom preventing proper maintenance and serving as a mosquito breeding ground. The failing pond
became an opportunity to demonstrate a large-scale bioretention area, or rain garden. With the
help of volunteers from Camellia Garden Club, the project was a success and serves as an example
for low impact development techniques.
BiLo Regional Pond
For years, the Caropines and Deerfield drainage basins in southeastern Horry County experienced
flooding problems due to drainage capacity issues. In 2008, Horry County acquired the space to
install a regional stormwater pond to handle the storm flow from these areas. The pond was
expanded in 2009. The pond is equipped with a fine mesh screen that prevents litter and debris
from passing through it into Lake Elizabeth in Surfside Beach. Furthermore, based on water quality
testing, the pond has proven effective at removing nutrients and bacteria from the water,
protecting the downstream recreational lakes and beaches. Click
here to see a water quality testing report from before and after pond construction.
Ultraviolet Disinfection Project at Pirateland Campground
In 2009, Horry County Stormwater installed an ultraviolet light disinfection system at Pirateland
Campground to treat bacteria-laden water in Blue Heron Pond before it discharges into the Atlantic
Ocean. Site selection was driven by public safety concerns. Before and after water quality
sampling was performed. The project has proven to be effective in treating water in Blue Heron
Pond. Click
here to see a report on the project.
Crabtree Swamp Watershed Floodplain Restoration
After almost a year in the making, in 2008, Horry County and the City of Conway signed a
Memorandum of Understanding with the Horry Soil and Water Conservation District and Crabtree Swamp
Watershed Conservation District to undertake an initiative to restore Crabtree Swamp to a more
natural state. The swamp was channelized in the 1960s by the U.S. Army Corps of Engineers for
agricultural drainage and again in the 1980s. Decades of maintenance led to a trapezoidal channel
with failing banks and an eroding channel bottom. In 2009, the group with help from partner
agencies (Coastal Carolina University, Clemson University, US Fish and Wildlife Service,
USDA/NRCS, SC DHEC, and US EPA) completed the first phase of a floodplain restoration project. The
project was designed to increase flood storage capacity, stabilize the banks, filter pollutants
from water with native plantings, and provide wildlife habitat. Project monitoring and assessment
is ongoing. The project was successful and a second phase is planned for 2012. For a project
report, click
here.
Azalea Ave parking Lot project
The Azalea Avenue Public Parking Lot, which was completed in May 2012, provides 49 new public
parking spaces in a community with a high demand for parking (adjacent to the Garden City Business
District and across the street from one of the more heavily used public beach access points in
Horry County). Due to the environmentally sensitive location of the new parking lot, permeable
interlocking concrete pavers were used for all of the parking spaces. These pavers allow storm
runoff to be infiltrated through the stone and gravel base and into the uncompacted native sandy
soil subgrade below. This direct infiltration has the additional water-quality benefit of keeping
pollutants in place in the underlying soil and pavement substructure rather than transporting them
directly into the nearby environmentally sensitive salt water tidal marshland.