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How do I use this website?
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How do I view images and files?
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What are LID BMPs and what value do they have
for my watershed?
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Why should I use LID BMP techniques?
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What are the costs associated with the use of
these techniques?
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Are LID BMPs reliable if they depend on property owners maintaining their on-site
practices?
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What about flood control?
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Where are successful examples of LID BMP
techniques?
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What does a typical LID BMP design look like?
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Where can additional information and guidance
be obtained?
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What
if I'm having trouble navigating the website? What do I
do?
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What is a QAPP?
1. How do I use this website?
Before you begin using this web-based template please read
through the information provided on this page. Once you
have familiarized yourself with some background information you
can continue on to the decision-making and design phase. A
site map has been included for your
convenience in navigating directly to a particular page in this
website. Also, a glossary has been included to clarify the
definitions of the terminology used. If you need
additional clarification please consider using an internet
search engine such as
Google.
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2. How do I view images and files?
Some images may appear small when you open them. There are
two options for viewing:
- To enlarge view - Click on the bottom right of
the image "Expand to Regular Size". You should see a small
icon with arrows in all directions.
- To save images and files - Right click on the
the link and choose "Save Target As". Save the file
(*.jpg, *.xls, *.pdf) to your computer.
- To view and print LID BMP Design Example images
- Left click on the link, X, to open the image.
Choose 'File > Page Setup' on the Toolbar and set "Orientation"
to 'Landscape'. Select 'OK'. Choose 'File > Print'
on the Toolbar and the file should print on one page.
Or right click on the the link and choose "Save Target As".
Save the file (*.jpg) to your computer. Then insert the
image into another program (e.g. Microsoft Power Point) and
print from there.
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3. What are LID BMPs and what value do they
have for my watershed?
A Low Impact Development (LID) best management practice (BMP) is
a stormwater management strategy concerned with maintaining or
restoring the natural hydrologic functions of a site to achieve
natural resource protection objectives and fulfill environmental
regulatory requirements.
LID BMPs employ a variety of natural and built features that
reduce the rate of runoff, filter out its pollutants, and
facilitate the infiltration of water into the ground. LID BMPs help to improve the
overall quality of receiving surface waters
and stabilize the flow rates of nearby streams.
The watershed values include the preservation/protection of
environmentally sensitive site features such as riparian
buffers, wetlands, steep slopes, valuable (mature) trees, flood
plains, woodlands, and highly permeable soils.
Key LID BMP
Elements (JPEG)
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4. Why should I use LID BMP techniques?
Stormwater management presents a wide array
of complex ecosystem and human health protection challenges. Many
of these are not addressed by conventional stormwater technology
or approaches, even as communities already struggle with the
economic reality of funding aging and ever-expanding stormwater
infrastructure. Adding the restoration of stream quality in
densely developed watersheds is even more daunting. Relying
only on impervious reduction and/or conventional detention ponds
to address these issues is not feasible, practical or sustainable.
LID BMPs provide basic new tools to (in order of preference):
control or at least minimize changes to the local hydrologic
system; keep runoff on site as much as possible; and as a last
resort, treat runoff before discharge to another system.
LID BMPs have numerous benefits and
advantages over conventional stormwater management approaches.
Taken together, the key components of LID---- conservation,
small-scale controls, directing runoff to natural areas,
customized site design, and maintenance, pollution prevention, and
education can enhance the local environment, protect public
health, and improve community livability - all while saving
developers and local governments money. In short, LID offers a
more environmentally sound technology and a more economically
sustainable approach to addressing the adverse impacts of
urbanization.
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5. What are the costs associated with the
use of these techniques?
A common concern is that LID-based projects will be more expensive because they
could require higher design and construction costs and a longer time to receive
project approval. This may or may not be true, depending on the experience of
the project consultants and contractors with these new techniques and the
receptiveness of local government officials to innovative practices. These
potential cost increases are not indictments of the concept of LID
BMPs but of
inexperienced institutions, individuals, and bureaucracies that remain unaware of
the great necessity for and benefits of a new approach.
Additional LID BMP cost concerns include the potential for greater expenses due to
the increased use of on-site landscaping material. Despite these issues,
experience has shown that LID BMPs still save money over conventional approaches
through reduced infrastructure and site preparation work. Case studies and pilot
programs show at least a 25 to 30% reduction in costs associated with site
development, stormwater fees, and maintenance for residential developments that
use LID BMP techniques. This savings is achieved by reductions
in clearing, grading, pipes, ponds, inlets, curbs and paving.
It is impractical to make broad
generalizations about costs because of the inherent variability
between sites and the complexity of management issues. Although
initial construction costs for LID BMPs may be higher than initial
costs for conventional stormwater practices, this initial expense
is often offset by cost savings in operations and maintenance.
This savings is possible because the maintenance of LID BMP
features can generally be incorporated into regular landscaping
maintenance activities and does not require expensive training or
hiring of a separate contractor for maintenance. Details for
specific LID BMPs are presented on this website.
Costs are very site specific. Each project will be unique based on the site's
soil conditions, topography, existing vegetation, land availability, etc.
On this website, fairly exact cost estimates are given for some of the
individual techniques. Keep in mind, however, that the actual costs will vary
greatly based on the character of the individual site and the creativity of the
designer.
Finally, costs are relative and considerations vary based on the user and
the project. For example, if a yard is retrofit to replace 1/2 of its area
with an LID infiltration practice such as a native vegetation rain garden,
does the homeowner perceive this as a loss of the use of the yard or a
benefit in the fact that there is now less lawn to maintain?
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6. Are LID BMPs reliable if they depend on property owners maintaining their on-site
practices?
Opponents of the residential use of LID BMPs have tried to simplify the approach by
characterizing it as only relying on rain gardens and rain barrels that will not
be maintained by the property owner. LID BMPs are much more than this.
They are a
comprehensive multi-system approach that has built-in redundancy, which greatly
reduces the possibility of failure. Many LID BMP techniques have nothing to do with
nor can they be significantly influenced by the behavior of the property owner. These include basic subdivision and infrastructure design features such as
reducing the use of pipes, ponds, curbs and gutters; maintaining recharge areas,
buffer zones, and drainage courses; using infiltration swales, grading
strategies, and open drainage systems; reducing impervious surfaces and
disconnecting those that must be used; and conserving open space.
The
long-term success of LID BMPs has much more to do with the knowledge, skills, and creativity
of the site designers than what the property owner does or doesn’t do. Maintenance agreements can be used if a developer is uncomfortable about on-site
landscaping features that also serve as stormwater controls. However, the key
factor in the success of LID BMPs is to ensure that the landscape practices (such as
rain gardens) are attractive and perceived by the property owner as adding value
to the property. If these LID BMPs are viewed as assets, the primary
motivation for their long-term maintenance is that of property owners protecting
their vested economic interests.
Additionally, experience has shown that
educational efforts can successfully promote active public engagement in
protecting our waters by the simple act of people maintaining their properties.
In actuality, LID BMP site source controls reduce maintenance burdens for property
owners and local governments. The techniques are simple, need no special
equipment or high costs to maintain, and encourage property owners to be
responsible for the impacts associated with their land.
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7. What about flood control?
Traditionally, stormwater management systems have been designed to function well
under a single design condition, e.g. the 100 year flood, the 10 year storm, etc. Designing control systems for a single extreme event does not mean that they will
perform adequately under other scenarios.
Flow control standards, which have their origin in ensuring
public safety and reducing property damage, have very little to do with ecosystem
protection. For preserving stream integrity, experience has demonstrated the
importance of a stormwater system that specifically addresses the frequent or
micro-storms that occur on a regular basis (weekly or monthly). By using
decentralized site-based source controls, LID BMPs use the stormwater from these more
frequent events as a resource and is an effective ecosystem approach. Additionally, if the full suite of LID
BMP controls and site design practices are
creatively used, LID BMPs are capable of automatically controlling the 10 and 100-year
storms through its primary strategy of restoring the built area's natural
rainfall-runoff relationship. The more techniques that are applied, the closer
to natural hydrologic function one gets. Where there are known flooding problems,
however, a hybrid approach may be needed to reduce liability and provide a sense
of safety. LID BMPs do not demand isolation from conventional technology. The
LID
national design manual recommends hybrid systems if site constraints warrant it.
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8. Where are successful examples of LID BMP
techniques?
Communities often have extensive watershed management and
natural resources conservation goals; master plans identify
sensitive environmental areas and preservation areas such as
wetlands, mature woods, and habitats. The LID site design should
address any potential impacts to these areas and encourage
conservation of these areas within the site. Here just a few
successful examples of LID BMP techniques:
http://www.lowimpactdevelopment.org/projects.htm
http://www.nrdc.org/water/pollution/storm/chap12.asp
Ipswich River, Massachusetts [link will be added]
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9. What does a typical LID BMP design look
like?
The following page provides an example of generic LID BMP
design:
Case Study
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10. Where can additional information and
guidance be obtained?
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11. What if I'm having trouble navigating
the website? What do I do?
- A
site map
has been included for your convenience in navigating directly to
a particular page in this website.
- Scroll to the top of the page and look for navigation
kernels (e.g.
Home
> FAQs >
Start >
Urban)
- Look in the light blue section on the right side of the
screen and click on
(<<
Back).
- Go to the
Contacts
page and send email to the webmaster.
12. What is a QAPP?
A QAPP is a Quality Assurance Project Plan. For a more
detailed description of QAPPs please visit the EPA Office of Water
website.
http://www.epa.gov/OWOW/monitoring/volunteer/qappcovr.htm
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