Presentation outlining different Low Impact Design Elements, how we as professionals can promote LID, and details steps that need to be taken to make LID cost effective

1. Low Impact Development

2. Low Impact Design Elements

3. GREEN ROOF
• Reduce water runoff from the roof of the
building
• Reduce the building’s energy use
• Extend the life of the roof
• Reduce heat island effect
• Prevent airborne pollutants from entering
stormwater system

4. BIORETENTION/RAIN GARDEN
• Soil and plant based filtration and retention
• Properly designed and constructed are able to achieve
removal of heavy metals and pollutants from parking areas
• Can effectively reduce quantity of runoff by retention
• Serve to increase groundwater recharge where suitable
conditions exist
• Can reduce thermal pollution

5. CISTERNS / RAIN BARRELS
• Harvest rainfall from rooftops or other impervious surfaces
• Results in reducing stormwater runoff entering either stormwater
system or adjacent drainages
• Can be either an above‐ground or below‐ground structure based on
aesthetic preference
• Water can used for landscape irrigation or activities such as washing of
cars
• Promotes water conservation
• Small scale use

6. RIPARIAN BUFFER RESTORATION / ENHANCEMENT
• Many buffers in Middle Tennessee have been significantly degraded
by agricultural activities, removal of canopy species, and encroachment
of non‐native invasive plant species
• Stable and vegetated riparian buffers provide important aquatic and
terrestrial habitats and filter run‐off from adjacent landscapes
• Restoration and enhancement of these areas should be pursued where
possible
• These activities can range from grading and bioengineering to
planting of a woody riparian buffer

7. CONSTRUCTED WETLANDS
• Constructed wetlands are an extremely effective practice for pollutant
removal
• They provide aesthetic value and wildlife habitat
• The directing of treated stormwater into natural areas such as
wetlands can be serve to enhance
the natural hydrology of these areas if done correctly
Requires extensive baseline data to understand natural system
and potential benefits

8. PERVIOUS SURFACES:
CONCRETE / PAVERS

9. INFILTRATION SWALE/DEPRESSED PARKING ISLANDS
• Runoff from roads, sidewalks, parking areas, and driveways can be
routed to infiltration swales
• Allow for water to infiltrate through a soil layer to an underlying drain
rock reservoir system
• Provides additional green space with both functional and aesthetic
values
• Use of these features minimizes need for conventional stormwater
infrastructure

10. LEVEL SPREADERS
• Disperse stormwater to create sheet flow and allow for uniform
flow across a slope
• Dissipates concentrated flows which generally lead to erosion
• Can be used adjacent to stream buffers, vegetated strips, or
bioretention structures

11. Low Impact Development
Key Elements
• Treat stormwater as a resource, not as a waste product
• Mimic the natural hydrology of a site
• Directing runoff to natural areas
• Balance of infiltration, evaporation, transpiration, and surface flow
• Maintenance, pollution prevention, and education
Benefits
• Prevent degradation of water quality and natural resources
• Manage stormwater efficiently and cost effectively
• Reduces demand on public stormwater infrastructure by reducing
run‐off volumes and peak stormwater flows
• Protect groundwater and drinking water supplies
• Help communities grow more attractively
• Serve as a tool to educate public about water issues

12. MOTIVATING FACTORS FOR LID
• Environment
•Reduce Pollution/Run‐off
•Increase habitat for wildlife
•Promote watershed health
• Market/Value Driven
•Adding aesthetically pleasing BMPs may increase property values/sales
•Establish a competitive advantage in marketplace
•Recognition for innovative design
• Regulatory
•Receive incentives (tax breaks, waive fees, speedy review, density bonus)
•Comply with federal, state and local regulations
•Meet water pollution control requirements for impaired water bodies

13. MYTHS AND MISCONCEPTIONS
• There are limits to where BMPs can be used.
• BMPs create standing water.
• BMPs detract from the value of a development.
• BMPs are not allowed in my area.
• Trying to include BMPs will slow down the review process and increase
development costs.
• BMPs are not cost effective.
• BMPs can solve all of my stormwater needs.

14. OVERCOMING OBSTACLES
Barriers of LID can come in a variety of sources
• Restrictive regulations and regulatory processes
• Resistance from the community
• Lack of technical knowledge
• Lack of resources ($$$)
Overcoming Obstacles:
• Take a proactive approach and addressing potential complications early
• Work with technical experts in BMP design
• Understanding the local regulatory environment
• Maintain open lines of communication with local municipalities and public
• Make allowances for learning curve – EDUCATION!!!

15. WHEN DOES LID MAKE SENSE?
• Land area requirements for detention storage and water quality
• Allowable run‐off volume
• On‐site water use requirements (irrigation)
• Groundwater recharge needs
• Landscape amenity opportunities
• Habitat created
• Recreational opportunities
• Reduce Flooding
• Reduce Combined Sewer Overflows (CSO)

16. WHEN DOES LID MAKE SENSE?
In reality, it’s all about development costs!!

17. VALUE ENGINEERING
“Value Engineering” – evaluate the relative benefits and costs of project
components and provide substitutions that will provide more value for
less cost.
• Estimate the value and cost of the project using only conventional drainage
approaches
• Estimate the value and cost of the project including low impact development practices
• Compare the two approaches and determine benefits or identify where LID practices
might be substituted for conventional approaches
• Identify where additional benefits might arise if code requirements were relaxed

18. WHAT CAN WE DO TO HELP PROMOTE LID???

19. SITE OWNERS AND DEVELOPERS
• Be clear about your desire to protect water resources and take a
holistic approach to stormwater management and site design
• Chose your design team based on past experiences and site designs
based on holistic water management
• Be present and active during the design and build phases to ensure
that your needs and requests are met
• Manage the work of your subcontractors to ensure proper installation
• Provide proper long‐term maintenance

20. CONSULTANTS
• Suggest to your clients the use of LID
• Help educate your client(s) about LID
• Strengthen your knowledge of federal, state, and local regulations
• Focus on trying to treat stormwater as a resource, not as a waste
product
• Be creative and offer good design and support
• Work with other groups to educate and promote LID

21. STORMWATER MANAGERS AND LOCAL MUNICIPALITIES
• Join forces with other departments or organizations
• Offer educational seminars
• Provide demonstration or pilot projects
• Allow flexibility in codes and regulations
• Strive to “set the bar higher”
• Offer incentives for projects with LID practices
• Provide “front of line” reviews (time is $)
• Offer recognition for innovation (good press)
• Offer conditional variances from codes or regulations (C&G, detention, narrower
streets, pervious pavement, shorter bldg setbacks)
• Provide tax breaks
• Waive impact/review fees
• Density bonuses

22. CASE STUDIES

23. CHICAGO, ILLINOIS
• Combined sewer overflow (CSO) system
• 1989 – Mayor Daley took office and established a goal to make
Chicago the greenest, most environmentally friendly city in nation
• “Green Streets Initiative”
• 583,000 trees planted (City maintained)
• 73 linear miles of medians reducing runoff, heat island, and inc. aesthetics
• 13.8% covered by tree canopy (increase of 3% since 1994 survey)
• Green roof program – over 80 green roofs in the city (2.5M sf)
•Incentives such as expedited reviews and density bonuses
• Chicago Center for Green Technology
• Municipal buildings go green
• Green permit program

24. SEATTLE, WASHINGTON
• Focuses on incorporating the use of highly visible, landscaped street
edges to manage stormwater
• Promotes narrower streets and porous sidewalks
• Incorporates vegetative swales, cascading pools, and rain gardens into
city R/W
• City worked with emergency and transportation departments

25. KANSAS CITY, MISSOURI
• Brush Creek and flooding issues in famous “Plaza” area
• Improve stormwater quality and reduce CSOs
• May 2005, “10,000 rain garden” initiative backed by Mayor Barnes
• Large media campaign with TV and radio education
• City sponsored education seminars
• City website with blogs, newsletter, H2O tips,
list of consultants, FAQ, and example pictures
• Demonstration projects

26. PORTLAND, OREGON
• Major CSO problems
• 1993 – Downspout Disconnection Program
•Over 50,000 homeowners have disconnected, reducing 1B GPY
• City has charged a stormwater utility fee since 1977
• In 2000, the city implemented a reward program
•Reduce SW utility fee by up to 30% by disconnecting down spouts, installing rain
gardens, and other LID BMPs
• Other Portland Initiatives
•Green Streets – street edge landscape, vegetated swales, pervious pavement, and
street trees to intercept and infiltrate stormwater
•Ecoroofs – Offer FAR bonuses for ecoroofs; all new city structures must be built
with ecoroofs
•BMP Monitoring – City monitors and measures results of green BMPs
•BMPs at schools – Portland schools has partnered with city to install facilities that
manage up to 90% of stormwater; Educate students

27. OTHER CASE STUDIES
• Jacksonville – Streamline the permit process (green goes to the front)
• Jacksonville – Local municipalities refund permit fees when projects
are LEED certified
• Pittsburgh – Property tax abatements for LEED certified projects
• Pittsburgh – Density bonuses for green projects
• Nashville – Moving towards a density bonus for LEED projects

28. QUESTIONS??