1. LIVING WITH LIDLIVING WITH LID
Site Design Implications of theg p
New C.3 Provisions
Mike Campbell, AICP, CPSWQ
April 23 2010April 23, 2010
2. Presentation AgendaPresentation Agenda
NPDES P it / P i i C 3• NPDES Permit / Provision C.3
• What Is LID?
– Definitions, Local Examples
• Case Studies / Alternative Designs• Case Studies / Alternative Designs
Using LID
R i l S l ti• Regional Solutions
• Conclusion
3. New NPDES Permits!New NPDES Permits!
• General Construction Permit –
adopted 9/2/09, effective 7/1/10, state-
wide, construction only.
• Municipal Regional Permit –
adopted 10/14/09, Bay Area MS4p y
dischargers only.
4. Municipal Regional
Permit (MRP)Permit (MRP)
Significant changes toSignificant changes to
Provision C.3 include:
– Low Impact Development
treatment controls required
for all new regulated public
d i t j t
HMH
and private projects
– Project size threshold forj
sites subject to
hydromodification controls
reduced to 1 acre (from 20(
acres)
5. Provision C 3 bii(1): Regulated Projects –Provision C.3.bii(1): Regulated Projects
Special Land Use Categories
- 10 000 s f threshold to be reduced to 5 000 s f10,000 s.f. threshold to be reduced to 5,000 s.f.
for auto service facilities, retail gasoline outlets,
restaurants & uncovered parking lotsrestaurants & uncovered parking lots
I l t ti d t 12/1/11- Implementation date: 12/1/11
6. Provision C 3 e: Alternative ComplianceProvision C.3.e: Alternative Compliance
O f ff- Option 1: treat a portion of the runoff with LID measures
onsite, and treat the remaining runoff with LID measures
at an offsite project in the same watershedat an offsite project in the same watershed
Option 2: treat a portion of the runoff with LID measures- Option 2: treat a portion of the runoff with LID measures
onsite, and provide in-lieu fees to treat the remaining
runoff with LID measures at a Regional Project in theg j
same watershed
7. Provision C 3 c: Low Impact DevelopmentProvision C.3.c: Low Impact Development
(LID)
- States that every regulated project must treat runoff with
100% LID measures onsite or at a joint treatment facility100% LID measures onsite or at a joint treatment facility
- LID measures defined as harvesting & re-use infiltrationLID measures defined as harvesting & re use, infiltration,
evapotranspiration, or biotreatment
Biotreatment can be considered only if it is infeasible to
implement harvesting & re-use, infiltration or evapotranspiration
at project siteat project site
- Implementation date: 12/1/11p
8. What is Low Impact Development (LID)?
• Goal is to reduce runoff and mimic a site’s
predevelopment hydrology by minimizing disturbedp p y gy y g
areas and impervious cover and then infiltrating, storing,
detaining, evapotranspiring, and/or biotreating
stormwater runoff close to its sourcestormwater runoff close to its source.
• Create functional and appealing site drainage that treats
stormwater as a resource rather than a waste product.p
• Practices include measures such as rain barrels and
cisterns, green roofs, permeable pavement, preserving
d l d d bi t t t th h iundeveloped open space, and biotreatment through rain
gardens, bioretention units, bioswales, and planter/tree
boxes.bo es
9. Issues to Manage for Successful LID
Implementation (Key Ingredients)Implementation (Key Ingredients)
• Local Policies – density and land useLocal Policies density and land use
• Public vs. Private Runoff
• Site Constraints – soil and groundwater
conditionsconditions
• Grading and Hydraulicsg y
• Landscape Design, Installation &
Maintenance
12. Recent examples of LID controls incorporatedp p
in local projects :
Green Roofs
13. Recent examples of LID controls incorporatedp p
in local projects :
Dual-use Infiltration Basin
14. Pervious Paving in Public
Park (interlocking pavers,
Pervious Paving in Parking
Lot (interlocking pavers)( g p ,
decomposed granite)
( g p )
15. Bioretention Area Adjacent to
Commercial Parking Lotg
Bioretention Cells Adjacent
to Recreational Facility
Parking LotParking Lot
16. Design Methodology for Volume-Based LID
Treatment Facilities
• Size facility by calculating storage capacity of facility as a function of rain gage
Treatment Facilities
y y g g p y y g g
data, unit basin storage, and size of drainage area
Unit basin storage: a function of soil type, % imperviousness & water quality storm size
• Design grading to convey surface runoff flows from paved surfaces to facility
• Verify surface slopes, pipe slopes, invert elevations to ensure system worksVerify surface slopes, pipe slopes, invert elevations to ensure system works
hydraulically
• Design drain down for the facility – must comply with local requirements (72 hrs.
t )typ.)
Goal: Look for ways to reduce drainage
i d i i di tarea size, reduce imperviousness, divert
flows to landscaping and create smaller
micro-treatment areas
17. Case Study 1 – Townhouse Development
2006 Approved Plan 2011 Plans
• Swales • Pervious concreteSwales
G
Pervious concrete
I filt ti b i• Grass pavers • Infiltration basins
• Below-ground
media filter vault
• Bioretention cells
22. 2011 Stormwater Control Plan – Solution 1
(Includes use of pervious concrete, infiltration basins with pumps)(Includes use of pervious concrete, infiltration basins with pumps)
27. 2011 Stormwater Control Plan – Solution 2
(Includes use of pervious concrete, basins with pumps, and bioretention cell)(Includes use of pervious concrete, basins with pumps, and bioretention cell)
29. Case Study 2 – Mixed Use Transit Oriented
DevelopmentDevelopment
2009 Approved Plan 2011 Plan
• Below-ground media
filter vault
• Below-ground
storage tanks
2009 Approved Plan 2011 Plan
filter vault
• Manhole media filter
storage tanks
• Green roofs• Manhole media filter
Grass pa ers
• Green roofs
Tree filters• Grass pavers • Tree filters
Bi t ti• Bioretention
P i t• Pervious concrete
33. 2009 Approved Stormwater Management Plan
(Includes use of mechanical treatment and grass pavers)(Includes use of mechanical treatment and grass pavers)
34. 2009 Design Features & Treatment Controls
Turf PaversMedia Filter Vault
Manhole Media
FilterFilter
35. 2011 Stormwater Management Plan – Solution 1
(Includes use of pervious concrete and underground storage facilities)(Includes use of pervious concrete and underground storage facilities)
37. 2011 Stormwater Management Plan – Solution 2
(Includes use of pervious concrete, underground storage, ext. green roof, bioretention
cells & tree filter)
38. 2011 Design Features & Treatment Controls
Solution 2Solution 2
Extensive Green Roof
Bioretention Cell
43. Regional ProjectsRegional Projects
• None currently available• None currently available
• Necessary for Alternative Compliance
(Provision C.3.e)
• HMH working with City of San Jose to
develop strategy (identify potential sites,
integrate with appropriate development
projects)
46. Take Home Points
L - Localized, landscaped-based
runoff management
I - Impervious surface reduction
D - Design creativity!
47.
48. #1 Hampton Park#1 - Hampton Park
(1097 Rock Ave.)
HMH (1570 Oakland Rd.)#2 - Lowe’s
(775 Ridder Park Dr )(775 Ridder Park Dr.)
#3 - Modern Ice
(652 Luna Park Dr.)
