Post-Construction Storm Water Control for New Developments and Redevelopment Projects

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Post-Construction Storm Water Control for New
Developments and Redevelopment Projects

• Presenters
• Christe Alwin, Lansing District Office
• Ralph Reznick, Nonpoint Source Unit

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MS4 Permit References

• Watershed Permit MIG610000
• Part 1.A.4.b.4. (Pages 15-17)
• Jurisdictional Permit MIS049000
• Part 1.A.8. (Pages 10-12)

City of Battle Creekporous pavement
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Core Requirement

• Develop, implement, and enforce a program through
  an ordinance or other regulatory mechanism to
  address post-construction storm water runoff
  from
• all new and redevelopment projects that disturb
  1 acre, and
• projects that disturb lt1 acre if they are part of
  a larger common plan of development or sale that
  would disturb 1 acre.

Applies to Permittee and Non-Permittee Projects
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What is Post-Construction Storm Water Runoff?
The storm water that would flow from a project
site to an MS4 or surface waters of the state
following construction.
City of Battle Creekgreen roof
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Scope of Post-Construction Control Requirements

• Watershed Permit
• Across the permittees jurisdiction in the
  regulated area (the Urbanized Area and watershed
  area).
• Jurisdictional Permit
• Discharges to the permittee owned or operated MS4
  within the Urbanized Area.

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Scope of Post-Construction Control Requirements

• Watershed Permit
• Across the permittees jurisdiction in the
  regulated area (the Urbanized Area and watershed
  area).
• Jurisdictional Permit
• Discharges to the permittee-owned or operated MS4
  with the Urbanized Area.

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Decision Flow Chart
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How is the post-construction program implemented
and enforced?

• Ordinance
• Other regulatory mechanism
• A combination of both

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Likely Scenarios for Applicability of Ordinance
and Other Regulatory Mechanisms
Permittee Type Ordinance Other Regulatory Mechanism Other Regulatory Mechanism
Permittee Type Ordinance Local Permit Program Internal Written Policy
City ? ?
Village ? ?
Township (Watershed General Permit) ? ?
Township (Jurisdictional General Permit) w/private discharges to its MS4 ? ?
Township (Jurisdictional General Permit) w/out private discharges to its MS4 ?
County Road Commission Both Both
County Drain Commissioner Both Both
County Administration Both Both
Public Institution ?
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Permittee Expectations

• Establish a post-construction control program
  through an ordinance or other regulatory
  mechanism.
• May rely on others to assist with completing the
  necessary reviews and calculations.

Compliance with permit requirements is ultimately
the responsibility of the permittee.
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Post-Construction Storm Water Runoff Control
Program Required Components

• Minimum Water Quality Treatment Volume Standard
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

City of Lansingraingardens
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• Program Components
• Minimum Water Quality Treatment Volume Standard
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

• Minimum Treatment Volumes
• 1 inch of runoff generated from the entire site
  (½ inch optional for the Watershed Permit if the
  Watershed Management Plan supports it)
• The calculated site runoff from the 90 percent
  annual non-exceedance storm for the region or
  locality

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10 Exceedance Storms for Michigan
Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code Location and Section Code
Kenton 1 Newberry 2 Kalkaska 3 Mio 4 Baldwin 5 Alma 6 Saginaw 7 Gull Lake 8 Lansing 9 Detroit Metro 10
10 percent exceedance storm 0.90" 0.80" 0.75" 0.76" 0.87" 0.92" 0.90" 0.95" 0.87" 0.89"
period of record evaluated 5/48-12/99 1/48-12/99 5/48-12/99 5/48-12/99 6/48-12/99 5/48-12/99 1/48-12/99 5/48-12/99 5/48-12/99 12/58-12/99
number of storms 3233 3868 4047 3480 3929 3437 3539 4009 3239 2944
minimum 0.10" 0.10" 0.10" 0.10" 0.10" 0.10" 0.10" 0.10" 0.10" 0.10"
median 0.28" 0.25" 0.25" 0.25" 0.27" 0.29" 0.29" 0.29" 0.27" 0.29"
mean 0.42" 0.38" 0.37" 0.36" 0.41" 0.43" 0.42" 0.43" 0.41" 0.42"
maximum 5.45" 4.18" 3.26" 3.13" 4.21" 9.33" 5.51" 3.95" 4.95" 4.34"
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Simple Method to Calculate Runoff Volume

• WQv Water Quality Volume
• (P)(Rv)(A) /12
• Rv 0.050.009(I)
• I Impervious Cover (Percent)
• Minimum Rv 0.2
• P 90 Rainfall Event Number
• A site area in acres

www.semcog.org/LowImpactDevelopment.aspx
Minimum Treatment Volume
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Treatment Design

• Treatment methods shall be designed on a
  site-specific basis to achieve the following
• Minimum of 80 percent removal of total suspended
  solids (TSS), as compared with uncontrolled
  runoff, or
• Discharge concentrations of TSS not to exceed 80
  milligrams per liter (mg/l)

    TSS TSS TSS
Land Use Category Percent Imperviousness Mean (mg/l) Min (mg/l) Max (mg/l)
Forest/Rural Open 2 51  --  --
Urban Open 11 51  --  --
Agricultural /Pasture 2 145  --  --
Low Density Residential 19 70 2 367
Medium Density Residential 38 70 2 367
High Density Residential 51 97 2 380
Commercial 56 77 5 280
Industrial 76 149 5 271
Highways 53 141 130 406
Taken from "Rouge River Wet Weather Demonstration Project, Selection of Stormwater Pollutant Loading Factors", RPO-MOD-TM34.00, October 1994, Table 3-13 Taken from "Rouge River Wet Weather Demonstration Project, Selection of Stormwater Pollutant Loading Factors", RPO-MOD-TM34.00, October 1994, Table 3-13 Taken from "Rouge River Wet Weather Demonstration Project, Selection of Stormwater Pollutant Loading Factors", RPO-MOD-TM34.00, October 1994, Table 3-13 Taken from "Rouge River Wet Weather Demonstration Project, Selection of Stormwater Pollutant Loading Factors", RPO-MOD-TM34.00, October 1994, Table 3-13 Taken from "Rouge River Wet Weather Demonstration Project, Selection of Stormwater Pollutant Loading Factors", RPO-MOD-TM34.00, October 1994, Table 3-13
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Treatment Mechanisms

• Settling
• Filtering
• Absorption
• Chemical Treatment
• Mechanical Treatment

Minimum Treatment Volume
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    TSS TP Sol P TN NOx Cu Zn
Stormwater Dry Ponds Stormwater Dry Ponds              
Quantity Control Pond Quantity Control Pond 3 19 0 5 9 10 5
Dry Extended Detention Pond Dry Extended Detention Pond 61 20 -11 31 -2 29 29
Group Median 1 Std. Dev Group Median 1 Std. Dev 47 32 19 13 -6 8.7 25 16 3.5 23 26 26 37
Stormwater Wet Ponds Stormwater Wet Ponds              
Wet Extended Detention Pond Wet Extended Detention Pond 80 55 67 35 63 44 69
Multiple Pond System Multiple Pond System 91 76 69 N/A 87 N/A N/A
Wet Pond Wet Pond 79 49 62 32 36 58 65
Group Median 1 Std. Dev Group Median 1 Std. Dev 80 27 51 21 66 27 33 20 43 39 57 22 66 22
Stormwater Wetlands Stormwater Wetlands              
Shallow Marsh Shallow Marsh 83 43 29 26 73 33 42
Extended Detention Wetland Extended Detention Wetland 69 39 32 56 35 N/A -74
Pond/Wetland System Pond/Wetland System 71 56 43 19 40 58 56
Submerged Gravel Wetland Submerged Gravel Wetland 83 64 -10 19 81 21 55
Group Median 1 Std. Dev Group Median 1 Std. Dev 76 43 49 36 36 45 30 34 67 54 40 45 44 40
Data based on fewer than five data points Data based on fewer than five data points Data based on fewer than five data points Data based on fewer than five data points          
NOTES                
N/A indicates that the data is not available. N/A indicates that the data is not available. N/A indicates that the data is not available. N/A indicates that the data is not available.          
TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus TSS Total Suspended Solids TP Total Phosphorus Sol P Soluble Phosphorus  
TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc TN Total Nitrogen NO Nitrate and Nitrite Nitrogen Cu Copper Zn Zinc    
National Pollutant Removal Performance Database,
2nd Edition Table 3.1 Median Pollutant Removal
() of Stormwater Ponds and Wetlands
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References
BMP Performance data can be found in
National Pollutant Removal Performance Database,
Version 3 at www.cwp.org/Resource_Library/Center_
Docs/SW/bmpwriteup_092007_v3.pdf
and The International Stormwater BMP Database
at http//www.bmpdatabase.org/Docs/Performance20
Summary20June202008.pdf
BMP design information can be found in
Low Impact Development Manual for Michigan
available at http//library.semcog.org/InmagicGen
ie/DocumentFolder/LIDManualWeb.pdf and the
Guidebook of BMPs for Michigan Watersheds
available at http//www.michigan.gov/deq/0,1607,7
-135-3313_3682_3714-118554--,00.html
Minimum Treatment Volume
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Minimum Treatment Volume
Total Area X 1 inch
or
90 percent annual non-exceedance storm and
appropriate runoff model applied to the site.
then
Apply BMP or BMPs necessary to achieve 80
reduction of Total Suspended Solids
Minimum Treatment Volume
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• Program Components
• Minimum Water Quality Treatment Volume
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

Existing levels runoff flow volume and rate for
the last land use prior to the planned new
development or redevelopment.

• Channel Protection Criteria
• Maintain post-development site runoff volume and
  peak flow rate at or below existing levels
• All storms up to the 2-year, 24-hour event

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Channel Protection Criteria
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Stream Stability
The ability of a stream, over time, to maintain
its pattern, dimension and profile such that, the
channel neither aggrades or degrades and is able
to transport without adverse impact the flow and
sediment from its watershed.
Channel Protection Criteria
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Definition Bankfull Discharge
That discharge which barely overtops the channel
banks
Maximum deposition erosion circulation cell
development
Channel Protection Criteria
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The most effective sediment discharge, over
time, occurs at the bankfull flow rate which is
between the 1 to 2 year recurrence interval.
At the bankfull flow, the stream bottom picks up
and moves, then redistributes its self in the
same pool riffle patterns existing prior to the
bankfull discharge.
Channel Protection Criteria
Taken from Rosgen, 1996
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Streams become unstable due to

• Changes in Climate
• Changes in Hydrology
• Changes in Topography
• Changes in Vegetation
• Changes in Geology
• Alterations of the Stream Channel

Channel Protection Criteria
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The Channel Protection requirements in the MS4
Permit address changes in hydrology due to
development and the negative channel responses
that result.
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Channel Protection Criteria
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Channel Protection Criteria
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Maintaining Predevelopment Hydrology

• Time of Concentration (Tc)
• The time it takes water to get from the farthest
  point in a watershed to a point of collection.
• Volume
• The quantity of water that runs off a site during
  a storm event.
• Peak Flow Rate
• The highest flow rate of a storm event.

Channel Protection Criteria
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CN
CN
Channel Protection Criteria
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Calculates rate and volume of storm runoff using
the unit hydrograph method for runoff
distribution and the curve number method of land
use runoff response.
www.michigan.gov/deqstormwater (under the
Municipal Program/MS4 Compliance Assistance
link, then the Guidance for Calculating Runoff
Volume and Peak Flow Rate link)
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24 HourPrecipitationRainfall Frequency Atlas
of the Midwest, Bulletin 71, Midwestern Climate
Center, 1992
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• Hydrograph for a farm on sandy soil or woods on
  loamy soil.

Qp23 cfs V5 acre-ft.
Dave Fongers - DNRE
Channel Protection Criteria
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Loss of infiltration due to development increases
total runoff volume and peak flows.
Qp65 cfs V11 acre-ft.
Qp23 cfs V5 acre-ft.
Dave Fongers - DNRE
Channel Protection Criteria
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More rapid runoff further increases peak flows.
Qp90 cfs V11 acre-ft.
Qp65 cfs V11 acre-ft.
Qp23 cfs V5 acre-ft.
Dave Fongers - DNRE
Channel Protection Criteria
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Controlling Time of Concentration

• Maintain Natural Drainage Paths
• Use open swales
• Increase surface roughness
• Detain flows
• Minimize disturbance
• Flatten grades in disturbed areas
• Disconnect imperviousness
• Connect pervious and vegetated areas

Channel Protection Criteria
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CN
CN
Channel Protection Criteria
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Runoff Curve Numbers For Urban Areas
Channel Protection Criteria
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1 Acre Site on C Soils
Runoff Volume to Remove 6310 ft3
Building
Meadow CN 71
Paved Parking
Paved Commercial Site 100 Impervious CN 98
Can be accomplished with rain gardens
on approximately 20 of site
2 year runoff volume 1640 ft3
2 year runoff volume 7950 ft3
Channel Protection Criteria
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Channel Protection Criteria
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Reduce Runoff Volume

• Infiltrate
• Evaporate
• Reuse

Channel Protection Criteria
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1 Acre Site on C Soils
Runoff Volume Reduction 1331 ft3
Open Space CN 79
Woods CN 70
2 year runoff volume 2847 ft3
2 year runoff volume 1516 ft3
Channel Protection Criteria
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Channel Protection
Determine Existing Runoff Volume Using CN Method
then
Determine Proposed Runoff Volume and Subtract
Existing to determine Runoff Volume Increase
then
Apply BMPs to Remove the Runoff Volume Increase
Channel Protection Criteria
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Channel Protection

• Meeting the Channel Protection Criteria for
  Volume Control will also meet the Peak Rate
  Control requirement in most cases.
• For NEW development, meeting the Channel
  Protection Criteria for Volume Control will also
  meet the Minimimum Water Quality Treatment Volume
  criteria in almost all cases.

Channel Protection Criteria
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Special Conditions

• Redevelopment
• Transportation
• Tight Soils
• Brown Fields

• Permittees are encouraged to discuss special
  conditions with District Staff.

Channel Protection Criteria
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• Program Components
• Minimum Water Quality Treatment Volume
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

Permittees shall include a requirement that the
developer prepare and implement site plans for
each project subject to the post-construction
control requirements.
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Site Plans
Site Plans

• Allows the permittee to require and evaluate
  post-construction control details at the planning
  stage.
• Sets a foundation for ensuring finished project
  sufficiently meets post-construction control
  requirements.
• Permittees should have a checklist or criteria
  for plan reviewers.

City of Battle Creekrain garden
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• Program Components
• Minimum Water Quality Treatment Volume
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

• Permittees shall ensure long-term Operation and
  Maintenance (OM) plans for the water quality
  treatment and channel protection controls the
  permittee requires.

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OM Requirements

• OM requirements shall be
• incorporated into the permittees
• ordinance or regulatory
• mechanism.
• Applies to structural and vegetative Best
  Management Practices (BMPs), including those
  owned or operated by the permittee.
• Permittees shall review OM plans and have a
  tracking mechanism for long-term OM.

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OM Recommendations

• Construction inspections, performance bonds, and
  self-certification process
• Routine ongoing
• inspections
• Maintenance
• agreements
• Tracking OM

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• Program Components
• Minimum Water Quality Treatment Volume
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

• The permittees ordinance and or regulatory
  mechanism is the foundation for implementing and
  enforcing the post-construction control program.

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Enforcement Mechanisms

• Ordinance and regulatory mechanism contents
  include all of the post-construction program
  components
• Treatment Volume Standard
• Channel Protection Criteria
• Developer Site Plan Requirement
• Operation and Maintenance Requirements
• Enforcement Mechanisms for Resolving
  Noncompliance
• Any Recordkeeping Requirements Placed on the
  Developer

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Enforcement Mechanisms

• Resolving noncompliance measures include but are
  not limited to
• Right of entry for inspections
• Triggers for issuing notices of violation
• Authority to require mandatory abatement
• Permittee authorization to conduct BMP
  maintenance and re-coup costs
• Ability to issue monetary penalties

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• Program Components
• Minimum Water Quality Treatment Volume
• Channel Protection Criteria
• Site Plan Requirements
• Operation and Maintenance Requirements
• Enforcement Mechanisms
• Recordkeeping Procedures

• Recordkeeping procedures shall be in place to
  document enforcement of the post-construction
  control program through the ordinance or other
  regulatory mechanism.

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Recordkeeping Requirements

• Copies of post-construction storm water control
  ordinances, regulatory mechanisms, and any
  supplemental procedures.
• Applicable records for all development and
  redevelopment projects required to comply with
  the post-construction program.

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Recordkeeping Requirements

• Developer Site Plan
• Checklists
• Correspondence
• Final approved design
• OM Plans or Agreements
• Inspection and certification records
• BMP tracking system
• OM inspections
• Enforcement Actions
• Violations
• Permittee actions to address violations

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Questions