1. Devon Rhodes
Rec 366
Best Management Practices
Best Management Strategies, or BMP’s as they are better known in the ecology and
environmental studies world, are the highest approved practices when it comes to dealing
with storm water and non-point pollution. The ideas within the Best Management
Strategies certainly try move away from the old schools of thought that formed most of the
storm water solutions of the past. Many of these ‘solutions’ were in fact, not solutions at all.
Some, like the system that is visible at Island Drive Park on Harbor Island, even create
greater problems or amplify the original one. When developing Best Management Practices
to deal with the issues like storm water run off and other non-point pollutions, the issues
must be examined from all sides. What causes pollutants such as this? Can those causes be
eradicated? If not, how can they be mitigated? And lastly, how can all parties involved
benefit from using the BMP’s.
Before discussing the Best Management Policies of storm water and non-point
pollutants, we need to know what it is we are managing. First, lets examine non-point
pollution. The Environmental Protection Agency defines non-point pollution as “… any
source of water pollution that does not meet the legal definition of "point source" in section
502(14) of the Clean Water Act.” Point source pollution is any pollution that has a
discernable and confined point of origin, such as “…pipe, ditch, channel, tunnel, conduit,
well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or
vessel or other floating craft…” Thus, non-point pollution is most often storm water that
does not enter any kind of drainage system before entering a major water source. Storm
water run off and non-point pollutions are issues affecting many populations, and it stems
directly from human development. The infiltration rate in the flat lands of the coast is
naturally fast enough to absorb water as it hits the ground with minimal run off or erosion
during normal weather events. That is, until impervious surfaces are introduced into the

2. mix. When storm water is funneled across impervious surfaces like concrete and roofing’s
the speed of the water is greatly accelerated causing the infiltration rate to lower. This
water also mixes with any and all pollutants or debris that is on the impervious surfaces.
This combination makes for a real issue. When the infiltration rate is to low then the water
is able flow rapidly toward the lowest elevation spot nearby. In the Wilmington and
Eastern Carolina ecosystem this most often is a water source. Ground infiltration is
important because it is a natural process in which the water is filtered through the soils
and vegetation as it makes its way toward the water table underground. This purifies the
water and also recharges our underground water sources and aquifers, from which we
often draw our drinking water. Infiltration also stops harmful erosion from occurring. As
water is rushed across impervious surfaces its speed is increased, detracting again from the
rate that water is able to seep through the topsoil. As it moves quickly across the ground it
picks up with it, the loose dirt atop of the topsoil. One of the finest examples of poor
management of storm water erosion due to impervious surfaces and poor drainage
techniques can be seen at Snow’s Cut Park in Carolina Beach, North Carolina. As the ground
already naturally sloped, the parking lot surface as well as River Road, which runs parallel
to the park, increased the speed of the water. As it rushed over the banks edge it quickly ate
away the integrity of the bank at an alarming rate. The effect has now reached a point of no
return and the county has decided to cuts its losses, and let this inlet claim what it will. This
is an example where Best Management Practices were not followed, and the consequences
have become apparent. Further more as the pollutants are picked up by the storm water,
funneled across non-porous surfaces, and dropped into our above-ground water sources
we again see its negative effects. Often water quality is lowered, species of wildlife that live
in and near these waters become affected, and this in turn affects us as the coastal
community. Prime example of this issue is seen in Bradley Creek. This watershed/estuary
ecosystem has become so polluted that the shellfish cannot be eaten whatsoever, and
swimming in its waters is purely dangerous for your health. Had the developers and the
City of Wilmington used Best Management Practices during the invasive land development
surrounding this Creek we may have seen a completely different Bradley Creek from what
we know today.

3. Storm water pollutants are most often considered point source pollutions when
define by the EPA. This is because of the storm water drain systems our municipalities and
governments have devised to eliminate flooding concerns. Take a walk down any
residential street and take a look along the curb as you walk. Drains lead to piping systems
underground. These piping systems often do not have any kind of filtration system, and
their stopping point is almost always a large body of surface water. Ultimately this
untreated, unfiltered water is funneled into our rivers, streams, wetlands, and eventually
our oceans. Storm water issues are generally the same as non-point source water
pollutants, minus some of the erosion concerns that non-point source water run off can
cause. These drains are certainly not Best Management Practices though, as they facilitate
pollutants quick and easy access to major water sources. As mentioned before Island Drive
Park is a prime example at just how far from a solution this system really is. Almost as soon
as the water is discharged from the street, it falls into the Intracoastal Waterway. Cars park
the streets, driveways made of non-permeable concrete drain directly to the street, and
highly manicured yards line the street (obviously fertilized and treated). All of these things
only contribute further to the failing storm water drain system. The question then arises,
how de we change these things? Certainly we cannot stop all development, so then what
changes in thinking and development practices need to occur to slow down this growing
problem and begin to restore the damage done.
Development will never stop. People will continue to exploit the land as a source of
income and livable space. In 2010, the National Oceanic and Atmospheric Administration
(NOAA) completed a survey in which they found that roughly 39 percent of America’s
population lives in counties directly touching the shoreline. As the population continues to
rise, so will the numbers of people fighting for space along the shoreline. Development will
continue to take over these pristine and crucial wetlands if left unchecked or unchanged.
The traditional approach to expanding has been what is referred to as sprawling. In an
ecosystem such as those that line or coastlines, sprawling directly affects every form of life.
The marshes, swamps, and wetlands that act as the natural filtration systems, are cleared,
cut down, leveled and paved over. Once these large impermeable surfaces are laid down,
non-point pollution is immediately amplified. The in-effective system of pipes and drains

4. designed to move the run off storm water drain directly into the closes water source they
can find. Sprawling creates huge developments of home and communities, which bring
their own concerns aside from the large amounts of impervious surfaces. These concerns
can include the uses of herbicides, fertilizers, and other chemicals used in high
maintenance landscaping. Further more, the introduction of non-native plants can also
become cause for concern. These species can become invasive, and take over the native
species that thrive in their natural habitat. Issues can arise with the wildlife of the area
when non-native plants are introduced. This can include limiting their natural habitat that
they would normally use for building families, or even harming the animals themselves if
the non-native species were to be toxic to them. These non-native plants, as well as the high
maintenance lawns, often crave large amounts of water. This is especially true within the
Southeast portion of the United States, where summers typically can be incredibly hot and
dry. This excessive use of water is taxing upon our drinking water sources. The Castle
Hayne Aquifer, which is eastern North Carolina’s source of underground fresh drinking
water, is directly affected by excessive water use. A report issued by the North Carolina
Department of Environment and Natural Resources Division of Water Resources in 2001
stated that “Estimated total pumping rates from these aquifers have increased from
120,000 gallons per day in 1910 (Lyke, Winner and Brockman, 1986) to 116 million gallons
per day at present (2001) (NC Division of Water Resources).” It goes on to say that water
levels in the Castle Hayne Aquifer have dropped by two to eight feet per year for almost
twenty-five years. Continuing, the study speaks about recharge rates, which in our area of
the Castle Hayne Aquifer average .5 to 1 inch per year. Suddenly, ‘keeping up with the
Jones’s yard’ doesn’t seem quite as important. As sprawling and poor development tactics
continue, these issues continue to rise.
If then, development and the expansion of non-permeable surfaces is the reason for
the increase in non-point pollutants and the main cause of storm water issues, then what
are the changes and solutions that we need to focus on in order to mitigate these issues.
First a change in mindset must occur. Instead of doing things the way they have always
been done, we need to adapt our developmental strategies to our growing knowledge of
the effects we have had on a vital ecosystem. This means a transition from conventional

5. development of land to a Low Impact Development System. A relatively young idea, the
strategies of Low Impact Development are best described by the EPA on their website, “LID
is an approach to land development (or re-development) that works with nature to manage
storm water as close to its source as possible.” ‘Working with nature’ is the key phrase. LID
tries to replicate the natural features of any land being developed in order to maintain the
high levels of natural filtration and absorption that existed previous to the lands
development. Conventional development strategies often utilized large detention ponds or
basins in which to drain the storm water and non-point run off. This is the reason for most
ponds and lakes that sub-divisional neighborhoods are centered around. Low Impact
Development suggests that this type of system does not work to up hold water quality
standards and in fact are more costly than the strategies suggested by Low Impact
Development. LID focuses on using small-scale techniques in order to manage the storm
water and non-point issues. By breaking down the strategies to a very ‘local’ level and
spreading those small-scale solutions throughout the development, Low Impact
Development effectively works to mitigate the run off issues better than those of
conventional development. Lets examine some of LID’s approaches to mitigation of storm
water and non-point run off.
First the Low Impact Developer must Asses the area on which they plan to build. Not
every technique in LID will work in every setting. However, assuming this developer was
working in the Wilmington area, most every LID approach will work. The assessment of the
land area must examine the key features of the site. These areas my be habitats for
endangered species, protected lands such as wetlands or drinking water sources, and/or
natural drainage sites. Understanding that these components are vital to the land and
water health of the area is crucial. These sites can then work towards the goal of draining
run off, as well as work naturally to filter the pollutants out prior to its infiltration of major
water sources. LID says to use the natural drainage paths already in place in nature. In
areas where this path needs to be diverged, or in order to guide possible run off to these
natural paths, swales should be used in place of curbside drains. A swale is comparable to
the drainage ditch system used in agriculture. In agriculture fields large V-ditches separate
cuts the ‘cuts’. These V-ditches ultimately drain into another, larger water source such as a

6. canal. But, in order to guide the excess water from the field plain to the original V-ditch
shallow trenches are dug, otherwise known as swales. These swales can be used effectively
to drain any type of developed land, and are less costly as well as pose less of a danger to
motorists or foot traffic.
Once the critical sites are documented, the land that is left can be deemed
developable. These areas are called building envelopes. Within these building envelopes
hard structures can be grouped. If the property was assessed correctly, each group of
structures will have its own natural drainage and filtration area nearby. The benefits of
using the building envelope strategy are economic and aesthetical in nature. By utilizing
natural drainage areas, the cost of digging large retention ponds if negated. Typically, the
larger and more prevalent natural greenspace there is, the more aesthetically pleasing an
area becomes. Letting the ground take care of filtration naturally is also a huge cost
reduction from having to process the water through a filtration plant or system (if they
even implement that system at all). Also using this a natural filtering system keep the water
a higher quality when it does reach the retention area, which in turn enhances the
aesthetics. Aesthetics then turns around and become economic benefits once again. The
higher quality green spaces and effective use of natural water sources raises property
values ultimately increasing profitability.
Once building starts, we then must assess the materials we use in order to maintain
open and permeable landscape. One of the largest issues, if not the largest issue, when
concerning storm water and non-point run off is concrete and cement. These impervious
surfaces aggravate erosion problems and do not allow for natural filtration to take place.
Thus, using Low Impact Development means preserving the most natural ground surface as
possible. When and where preserving the real, natural ground space is not an option (such
as roads) progressive and innovative ideas must be used. One such idea is the ‘popcorn’
style of cement. This concrete is made to drain water through it, as to stop major run off
issues. Studies have shown that drainage rate average about 480 inches per hour. That
equals roughly 5 gallons per square foot per minute. We visited a site during one of our
field trips that had used this type of cement for their parking lot. The site was the Ann
McCrary Park. While speaking about the type of concrete used Dr. Herstine pointed out that

7. these permeable surfaces also included a type of bacteria that further enhanced the
filtration of the run off water before entering the ground. A flyer distributed by the South
Carolina Department of Natural Resources states that, “The open cell structure of pervious
concrete provides a media for aerobic bacteria that break down many of the pollutants that
seep from parked cars.” Further more the use of this type of material also reduces the need
for larger retention ponds, thus furthering the aesthetics (and ultimately the economics) of
the developed land.
As development continues we must further localize the efforts to mitigate the run
off and pollution issues caused by storm water and non-point water pollutants. At the ‘ per-
yard’ level we can begin to utilize native plants, rain gardens, rain barrels, and green roofs.
Planting vegetation is a crucial part of slowing and filtering run off water. The use of native
plants is a fundamental in this step. Native plants will provide the natural species within
the area home habitats, the will grow and blossom without extraneous water usage, and
will protect the unique characteristics of that specific biosphere. Native plants are best
suited for the unique features of the climate, and are more resistant to the local threats that
are a part of the natural ecosystem. In some circumstances it is not enough to only have the
native plants. Some land grades are too steep or the ground in that area is not absorbent
enough to stop excessive run off. In these places rain gardens can be utilized. A rain garden
is almost exactly what it sounds like, a garden utilizing the storm water as its main
resource. To build a rain garden and indention must be dug. This area, once lowered, will
automatically attract rainwater as it tries to find the lowest point of elevation in which to
drain. This indention is the refilled with porous natural materials. At Alderman Elementary
School, where our class did a service-learning project, the rain garden area utilized sand,
mulch, and porous topsoil. This area can then be planted with the native vegetation. This
area will act as a natural drainage spot for flowing storm water; swales can be used
conjunction with this. Water will be given an exceptional area to be filtered before it enters
ground-water sources. The native pants will also flourish in this fertile area. During times
of drought or dry seasons, water from a rain barrel can be utilized to water plants and
vegetation within the yard. A rain barrel is exactly what it sounds like. Placed beneath
drainage points from hardened structures (usually underneath gutter systems), the barrel

8. collects water run off like a cistern. This helps to prevent erosion that would be caused by
immediate drainage to the ground from these gutter systems. Erosion at these points can
be a real issue because of the degradation that it can cause to the foundations of these
hardened structures. Water caught in this barrel can be used to water vegetation, poured
into the rain garden, or even left to evaporate from the barrel. Even before water reaches
the gutters of a building there is a step that can be utilized. This is called the green roof. A
relatively young idea here in North America, it has become largely used in Europe. The
technology uses a growing medium, filtration, drainage, water/root repellant, thermal
insulation, and vapor control layers. Using green roofs absorbs some of the falling storm
water and slows the drainage of that water, to lessen the impact it will have as it reaches
the ground. Other benefits of this roofing layer include natural habitat for native species,
absorbance of air and sound pollution, as well as further insulating the hard structure.
In conclusion we have seen that Best Management Practices, Low Impact
Developments, and the steps taken to achieve these ideas include benefits across the board.
Developers can see a reduction in cost, an increase in property values, fewer ‘impact’ fines,
and a better reputation. The local governments and municipalities can see the benefits
from the increase in tax revenues that will come from increasing populations utilizing Low
Impact Developments, they will benefit from new partnerships and better relationships
with the private developers and contractors, and possibly one of the largest benefits to a
local government will be to reduction of flooding concerns. Especially in the coastal
counties, towns, and cities of eastern North Carolina, flooding comes as a major economic
setback. Such places as Washington, Plymouth, Creswell, and certainly hundreds of other
small towns bordering major surface water or tributaries to major surface waters could see
huge economic benefits from the reduction of flood damage costs. Further more,
homeowners are benefitted by these practices by the high level of aesthetics created, the
protection of drinking water sources, and the increased (and holding) property values. And
of course Best management practices directly benefit the environment. For every reason
stated throughout the above dialogue, and more, the environment can survive and thrive
when Best Management Practices are put in place.

9. Bibliography
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