Low-Impact Development (PDF)

. 
  
TOWN OF 
WATERFORD 
Low Impact 
Development 
Want to learn more about low 
impact development and 
stormwater management? 
An  Environmentally-Friendly 
Alternative to Conventional Urban 
Development 
http://nemo.uconn.edu 
 
CT Nonpoint Education for Municipal Officials 
(CT NEMO) has information on  MS4, nitrogen 
reduction, rain gardens, and an LID atlas that 
indicates where LID has been implemented in 
Connecticut.  
 
————————————— 
 
https://www.epa.gov/green-
infrastructure  
 
The Environmental Protection Agency offers 
resources to assist with planning, design, oper-
ating, maintaining, and funding LID and other 
forms of green infrastructure.  
 
————————————— 
 
www.ct.gov/deep/
greeninfrastructure 
 
The Connecticut Department of Energy and 
Environmental Protection has an extensive 
collection of photos at different LID implemen-
tation sites across the state. It also has links to 
information on LID and on CT DEEP’s programs 
regarding stormwater issues.  
Bioretention Island 
Great Neck School 
Roadside vegetated swale Giovanni Drive 
Rain barrels Oswegatchie School 

Pavers function to increase 
permeability and reduce run
-off. While conventional 
pavement does not allow 
water to infiltrate, spaces 
within and between pavers 
allow water to infiltrate into 
the soil, reducing the volume 
of runoff that comes off of 
sidewalks, roads, and park-
ing lots. These concrete pavers are located at Great 
Neck School. 
Bioretention areas are similar to rain gardens, but are  
larger in size and designed to detain or retain 
stormwater flow. They are 
vegetated depressions that 
collect and filter run-off or 
infiltrate it into the ground 
and reduce runoff volume.  
Vegetation and soil media 
sustain microorganisms 
which help remove nutrients 
from the runoff.  
 
What is low impact 
development? 
Low impact development (LID) refers to systems 
and practices that minimize the effects of urban 
development on the natural hydrology of an 
area by integrating and/or mimicking natural 
processes that allow for water to evaporate 
and infiltrate the soil. 
What are the benefits 
of LID? 
 
Low impact development restores or maintains 
the ability for water to cycle freely throughout 
the ecosystem. Traditional urban development 
includes impervious roads and parking areas 
that prevent water from infiltrating the soil and 
being taken up by plants.  During storm events, 
water cannot evaporate quickly enough, so it  
flows off these impervious surfaces as runoff. 
Runoff carries pollutants and nutrients as it flows 
over land and can degrade the quality of the 
water bodies it flows into. By allowing water to 
flow into the soil,  low impact development 
reduces runoff from storm events significantly. 
 
 
 
 
Green roofs are roofs that 
are host to a garden of low
-maintenance vegetation. A 
layer of waterproof 
material separates the 
actual roof from the 
garden to prevent leaking 
of rainwater. The 
vegetation is drought-
resistant and able to 
withstand the extreme heat and winds that a roof can be 
exposed to. In addition to reducing stormwater runoff, 
green roofs provide insulation to the buildings it lies on top 
of, which can help to reduce energy costs.  
University of Connecticut 
Rain gardens are vegetated areas that collect run-off 
in shallow depressions and 
allow it to seep into the soil. 
They can support a variety 
of vegetation and are 
usually located to intercept 
run-off from a roof or 
driveway. By infiltrating 
runoff into the soil, 
pollutants are kept out of 
nearby streams and Long 
Island Sound. 
  
Pervious asphalt is functionally identical to normal asphalt; 
however the pervious asphalt mixture lacks finer aggregates, 
resulting in  void space that water can seep into. From there, 
it can percolate into the underlying soil or   evaporate.  
Pervious asphalt must 
be maintained 
periodically, to vacuum 
and remove fines that 
may clog  void space. 
spaces and reduce the 
asphalt’s ability to 
absorb water.  Pervious 
asphalt parking area 
at O’Neill Theatre. 
Tree box filters 
function similarly to 
rain gardens; they are 
placed on or near 
roads, sidewalks, or 
parking lots to absorb 
stormwater runoff. The 
engineered soil 
medium helps to 
improve water quality 
by removing common 
pollutants from 
stormwater before it 
is absorbed into the 
soil surrounding the filter. In heavy rain events, an outflow 
pipe discharges excess water to the town’s storm drain 
Bioretention area in 
Giovanni Drive cul-de-sac 
LID Examples 
LID Examples 
Waterford High School