Low Impact Development
& Nonpoint Source
Define Low Impact Development
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.
LID employs principles such as
preserving and recreating
features, minimizing effective imperviousness to create functional and
appealing site drainage that treat storm water as a resource rather than a waste
There are many practices that have been used to adhere to these principles
bioretention facilities, rain gardens, vegetated rooftops, rain
By implementing LID principles and practices, water can be managed in a way
that reduces the impact of built areas and promotes the natural movement of
water within an ecosystem or watershed.
Applied on a broad scale, LID can maintain or restore a watershed's hydrologic
and ecological functions.
Nonpoint Source Pollution
Excess fertilizers, herbicides, and insecticides from agricultural lands
and residential areas
Oil, grease, and toxic chemicals from urban runoff and energy
Sediment from improperly managed construction sites, crop and forest
lands, and eroding stream banks
Salt from irrigation practices and acid drainage from abandoned mines
Bacteria and nutrients from livestock, pet waste, and faulty septic
Atmospheric deposition and hydromodification
Nonpoint Source Pollution cont.
Comes from many diffuse sources such as rainfall or
snowmelt moving over and through the ground
Results from land runoff, precipitation, atmospheric
deposition, drainage, seepage, or hydrologic
Impacts of land use on watersheds
Land uses from any part of the watershed
polluted runoff from farms, forests and homes
affect the health of the whole watershed.
Land use practices such as
clearing land for timber or
agriculture, developing and maintaining roads,
housing developments, and water diversions
environmental consequences that greatly affect stream
even when the activity is not directly
associated with or near a stream
Proper planning and adequate care in implementing
projects can help ensure that one activity within a
watershed does not detrimentally impact the downstream
In a healthy watershed, after a rain event, vegetation and
wetlands intercept and slow the flow of water as it travels
through the watershed, removing sediment and allowing large
quantities of water to enter the soil and percolate into the
This groundwater is then available to contribute to late season
stream flow, to the benefit of fisheries and water quality.
In comparison, a watershed with more impervious surfaces and
the loss of vegetation and wetlands, responds differently after a
More water runs over the land instead of replenishing
This larger volume of water quickly reaches water bodies
reducing the time available for the water to be cleansed and
filtered and also causing erosion of stream banks.
Most human activities and development have the potential to
adversely affect the overall health and quality of a watershed.
on unstable slopes can cause erosion.
can increase levels of harmful bacteria
and overload runoff with nutrients.
Also, poorly planned
urban and industrial growth
many of the same problems as farming and timber harvest in
addition to contamination from toxic chemicals.
Even seemingly harmless activities such as
and recreational activities
along rivers and creeks can be
harmful, impacting the watershed's sensitive riparian vegetation
which is important for water quality protection and wildlife
When viewed individually, most human activities have
little effect on the general health of the watershed.
However, the effects of numerous activities within a
watershed are cumulative and when combined can greatly
diminish the watershed's overall health.
Every activity has the potential to impact the area of the
As people place more demands on a watershed,
greater efforts must be made to reduce these
Having clean water will require communities to work
together to ensure that activities do not negatively impact
In the 2000 National Water Quality Inventory, states reported that
agricultural nonpoint source (NPS) pollution
is the leading source
of water quality impacts on surveyed rivers and lakes, the second
largest source of impairments to wetlands, and a major contributor to
contamination of surveyed estuaries and ground water.
Agricultural activities that cause NPS pollution include poorly located
or managed animal feeding operations;
overgrazing; plowing too
often or at the wrong time; and improper, excessive, or poorly
timed application of pesticides, irrigation water, and fertilizer.
Pollutants that result from farming and ranching include
nutrients, pathogens, pesticides, metals, and salts
Impacts from agricultural activities on surface water and ground water
can be minimized by using management practices that are adapted to
Many practices designed to reduce pollution also increase productivity
and save farmers and ranchers money in the long run.
Did you know that runoff from farms is the leading
source of impairments to surveyed rivers and lakes?
There are many government programs available to help farmers and
ranchers design and pay for management approaches to prevent and
control NPS pollution.
For example, over 40 percent of section 319 Clean Water Act grants
have been used to control NPS pollution from working farms and
Also, many programs funded by the U.S. Department of Agriculture
and by states provide cost
share, technical assistance, and economic
incentives to implement NPS pollution management practices.
Many local organizations and individuals have come together to help
create regional support networks to adopt technologies and practices to
eliminate or reduce water quality impacts caused by agricultural
Conventional Development vs.
Conventional development techniques often clear all
trees and valuable topsoil from a site and re
grade it so
that all water ends up in one large detention basin.
Resulting problems include
loss of recharge,
increased water temperature, decreased water
quality and higher runoff volumes
The LID approach protects the natural ability of the
site to capture precipitation, keep it clean and allow it
to recharge the local water table.
LID Best Management Practices and
The use of best management practices to reduce the
amount of impervious surfaces, disconnect flow paths
(i.e., downspouts connected to storm sewers), and
treat storm water at its source all help
impacts to water quality and local hydrology
Pro’s of applying LID
Provides energy at an affordable cost
Minimizes land clearing and grading costs
Reduces infrastructure costs (streets, curbs, gutters,
Reduces storm water management costs (reduces or
eliminates storm sewers and ponds)
Increases lot and community marketability
Increases lot sale yields and reduces permit fees
Protects site and regional water quality by reducing sediment,
nutrient, and toxic loads to water bodies
Balances growth needs with natural resource protection
Reduces municipal infrastructure and utility maintenance costs
(streets, curbs, gutters, sidewalks, storm sewers and ponds)
Fosters public/private partnerships
Provides local accessibility to open spaces, recreation and
Preserves and protects amenities that can translate into more
saleable homes and communities
Provides shading for homes and properly orients homes to help
decrease monthly utility bills
Preserves integrity of ecological and biological systems
Protects site and regional water quality by reducing
sediment, nutrient, and toxic loads to water bodies
Reduces impacts to local terrestrial and aquatic plants and
Preserves trees and natural vegetation
Creates connected corridors of wildlife habitat
Supplies have to be specially ordered
Not significantly different compared to what we
Not well known
People refuse to use it.
Building set backs
Naturally vegetated buffers
Natural vegetation should be preserved
Steep slopes should not be disturbed
Bio retention areas
Native plant landscaping
Permeable or porous pavement
Reduced in impervious surfaces
Disconnected down spouts
Green roof system
What can communities do?
Start using LID for community building/municipal
Make laws to enforce LID
Encourage others to use LID
Reach out to developers
Get projects on the ground
Make sure ordinances are LID friendly
Use less pavement
Soils, wildlife, forestry, and aquatics affect and
are affected by nonpoint source pollution and its
reduction and LID
Polluted storm water runoff can have many adverse effects on plants,
fish, animals, and people.
Sediment can cloud the water and make it difficult or impossible for
aquatic plants to grow.
Sediment also can destroy aquatic habitats
Excess nutrients can cause algae blooms. When algae die, they sink to
the bottom and decompose in a process that removes oxygen from the
Fish and other aquatic organisms can’t exist in water with low dissolved
Bacteria and other pathogens can wash into swimming areas and create
health hazards, often making beach closures necessary.
plastic bags, six
pack rings, bottles, and cigarette
washed into water bodies can choke, suffocate, or disable
aquatic life like ducks, fish, turtles, and birds.
Household hazardous wastes like insecticides, pesticides, paint,
solvents, used motor oil, and other auto fluids can poison
Land animals and people can become sick or die from eating
diseased fish and shellfish or ingesting polluted water.
Polluted storm water often affects drinking water sources. This,
in turn, can affect human health and increase drinking water
Washing your car and degreasing auto parts at home
can send detergents and other contaminants through
the storm sewer system.
Dumping automotive fluids into storm drains has the
same result as dumping the materials directly into a
Excess fertilizers and pesticides applied to lawns and
gardens wash off and pollute streams.
In addition, yard clippings and leaves can wash into
storm drains and contribute nutrients and organic
matter to streams.
Leaking and poorly maintained septic systems release
nutrients and pathogens (bacteria and viruses) that
can be picked up by storm water and discharged into
nearby water bodies.
Pathogens can cause public health problems and
Pet waste can be a major source of bacteria and excess
nutrients in local waters.
Dirt, oil, and debris that collect in parking lots and
paved areas can be washed into the storm sewer
system and eventually enter local water bodies.
Erosion controls that aren’t maintained can cause
excessive amounts of sediment and debris to be carried
into the storm water system.
Construction vehicles can leak fuel, oil, and other
harmful fluids that can be picked up by storm water
and deposited into local water bodies.
Improperly managed logging operations can result in
erosion and sedimentation.
Uncovered fueling stations allow spills to be washed
into storm drains.
Cars waiting to be repaired can leak fuel, oil, and other
harmful fluids that can be picked up by storm water.