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Transcript of Post-Construction Storm Water Control for New Developments and Redevelopment Projects Presenters:...
Post-Construction Storm Water Post-Construction Storm Water Control for New Developments Control for New Developments and Redevelopment Projectsand Redevelopment Projects
Presenters:Presenters:Christe Alwin, Lansing District OfficeChriste Alwin, Lansing District OfficeRalph Reznick, Nonpoint Source UnitRalph Reznick, Nonpoint Source Unit
MS4 Permit ReferencesMS4 Permit References
Watershed Permit MIG610000Watershed Permit MIG610000Part 1.A.4.b.4. (Pages 15-17)Part 1.A.4.b.4. (Pages 15-17)
Jurisdictional Permit MIS049000Jurisdictional Permit MIS049000Part 1.A.8. (Pages 10-12)Part 1.A.8. (Pages 10-12)
City of Battle Creek—porous pavement
Core RequirementCore Requirement Develop, implement, and enforce a Develop, implement, and enforce a
program through an ordinance or other program through an ordinance or other regulatory mechanism to address post-regulatory mechanism to address post-construction storm water runoff from:construction storm water runoff from: all new and redevelopment projects that all new and redevelopment projects that
disturb disturb ≥≥1 acre, and1 acre, and projects that disturb <1 acre if they are part of projects that disturb <1 acre if they are part of
a larger common plan of development or sale a larger common plan of development or sale that would disturb that would disturb ≥≥1 acre.1 acre.
Applies to Permittee and Non-Permittee Projects
What is Post-Construction Storm What is Post-Construction Storm Water Runoff?Water Runoff?
City of Battle Creek—green roof
The storm water that would flow from a project site to an MS4 or surface waters of the state following construction.
Scope of Post-Construction Control Scope of Post-Construction Control RequirementsRequirements
Watershed Permit:Watershed Permit: Across the permittee’s jurisdiction in the Across the permittee’s jurisdiction in the
regulated area (the Urbanized Area and regulated area (the Urbanized Area and watershed area).watershed area).
Jurisdictional Permit:Jurisdictional Permit: Discharges to the permittee owned or Discharges to the permittee owned or
operated MS4 within the Urbanized Area.operated MS4 within the Urbanized Area.
Example 1 - Permittee with Watershed Permit
MS4 A
MS4 B
MS4 D
MS4 C
Deferred Watershed
Watershed Not Deferred
Urbanized Area
Scope of Post-Construction Control Scope of Post-Construction Control RequirementsRequirements
Watershed Permit:Watershed Permit: Across the permittee’s jurisdiction in the Across the permittee’s jurisdiction in the
regulated area (the Urbanized Area and regulated area (the Urbanized Area and watershed area).watershed area).
Jurisdictional Permit:Jurisdictional Permit: Discharges to the permittee-owned or Discharges to the permittee-owned or
operated MS4 with the Urbanized Area.operated MS4 with the Urbanized Area.
Example 2 – Permittee with Jurisdictional Permit
MS4 A MS4 CUrbanized Area
MS4 B
Non-Urbanized Area
MS4 D MS4 E
How is the post-construction program How is the post-construction program implemented and enforced?implemented and enforced?
OrdinanceOrdinanceOther regulatory mechanismOther regulatory mechanismA combination of bothA combination of both
Likely Scenarios for Applicability of Ordinance Likely Scenarios for Applicability of Ordinance and Other Regulatory Mechanismsand Other Regulatory Mechanisms
Permittee Type
Ordinance
Other Regulatory Mechanism
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
County Drain Commissioner Both
County Administration Both
Public Institution ♦
Permittee ExpectationsPermittee Expectations
Establish a post-construction control program through Establish a post-construction control program through an ordinance or other regulatory mechanism.an ordinance or other regulatory mechanism.
May rely on others to assist with completing the May rely on others to assist with completing the necessary reviews and calculations.necessary reviews and calculations.
Compliance with permit requirements is Compliance with permit requirements is ultimately the responsibility of the ultimately the responsibility of the
permittee.permittee.
Post-Construction Storm Water Runoff Post-Construction Storm Water Runoff Control Program Required ComponentsControl Program Required Components
Minimum Water Quality Treatment Volume Minimum Water Quality Treatment Volume StandardStandard
Channel Protection CriteriaChannel Protection Criteria Site Plan RequirementsSite Plan Requirements Operation and Maintenance RequirementsOperation and Maintenance Requirements Enforcement MechanismsEnforcement Mechanisms Recordkeeping ProceduresRecordkeeping Procedures
City of Lansing—raingardens
Program Components
Minimum Water Quality Treatment Volume StandardChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
Minimum Treatment Volumes:Minimum Treatment Volumes:
1 inch of runoff generated from the entire site (½ inch 1 inch of runoff generated from the entire site (½ inch optional for the Watershed Permit if the Watershed optional for the Watershed Permit if the Watershed Management Plan supports it)Management Plan supports it)
The calculated site runoff from the 90 percent annual The calculated site runoff from the 90 percent annual non-exceedance storm for the region or localitynon-exceedance storm for the region or locality
Location and Section CodeLocation and Section Code
KentonKenton11
NewberryNewberry22
KalkaskaKalkaska33
MioMio44
BaldwinBaldwin55
AlmaAlma66
SaginawSaginaw77
Gull Gull LakeLake
88
LansingLansing99
Detroit Detroit MetroMetro
1010
10 percent 10 percent exceedance exceedance stormstorm
0.90"0.90" 0.80"0.80" 0.75"0.75" 0.76"0.76" 0.87"0.87" 0.92"0.92" 0.90"0.90" 0.95"0.95" 0.87"0.87" 0.89"0.89"
period of period of record record evaluatedevaluated
5/48-5/48-12/9912/99
1/48-12/991/48-12/99 5/48-12/995/48-12/99 5/48-5/48-12/9912/99
6/48-6/48-12/9912/99
5/48-5/48-12/9912/99
1/48-12/991/48-12/99 5/48-5/48-12/9912/99
5/48-5/48-12/9912/99
12/58-12/58-12/9912/99
number of number of stormsstorms
32333233 38683868 40474047 34803480 39293929 34373437 35393539 40094009 32393239 29442944
minimumminimum 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10" 0.10"0.10"
medianmedian 0.28"0.28" 0.25"0.25" 0.25"0.25" 0.25"0.25" 0.27"0.27" 0.29"0.29" 0.29"0.29" 0.29"0.29" 0.27"0.27" 0.29"0.29"
meanmean 0.42"0.42" 0.38"0.38" 0.37"0.37" 0.36"0.36" 0.41"0.41" 0.43"0.43" 0.42"0.42" 0.43"0.43" 0.41"0.41" 0.42"0.42"
maximummaximum 5.45"5.45" 4.18"4.18" 3.26"3.26" 3.13"3.13" 4.21"4.21" 9.33"9.33" 5.51"5.51" 3.95"3.95" 4.95"4.95" 4.34"4.34"
10% Exceedance Storms for Michigan10% Exceedance Storms for Michigan
Simple Method to Calculate Simple Method to Calculate Runoff VolumeRunoff Volume
WQv = Water Quality VolumeWQv = Water Quality Volume = [(P)(Rv)(A)] /12 = [(P)(Rv)(A)] /12
Rv = 0.05+0.009(I)Rv = 0.05+0.009(I)I = Impervious Cover (Percent)I = Impervious Cover (Percent)Minimum Rv = 0.2Minimum Rv = 0.2P = 90% Rainfall Event Number P = 90% Rainfall Event Number A = site area in acresA = site area in acres
www.semcog.org/LowImpactDevelopment.aspx
Minimum Treatment Volume
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
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)
Treatment DesignTreatment Design
Treatment MechanismsTreatment Mechanisms
• Settling• Filtering• Absorption• Chemical Treatment• Mechanical Treatment
Minimum Treatment Volume
TSS TP Sol P TN NOx Cu Zn
Stormwater Dry Ponds
Quantity Control Pond* 3 19 0 5 9 10 5
Dry Extended Detention Pond 61 20 -11 31 * -2* 29* 29*
Group Median ± 1 Std. Dev 47 ±32 19 ±13 -6 ± 8.7 25 ±16 3.5 ±23 26* 26 ±37
Stormwater Wet Ponds
Wet Extended Detention Pond 80 55 67 35 63 44 69
Multiple Pond System* 91 76 69 N/A 87 N/A N/A
Wet Pond 79 49 62 32 36 58 65
Group Median ± 1 Std. Dev 80 ±27 51 ±21 66 ±27 33 ±20 43 ±39 57 ±22 66 ±22
Stormwater Wetlands
Shallow Marsh 83 43 29 26 73 33 42
Extended Detention Wetland* 69 39 32 56 35 N/A -74
Pond/Wetland System 71 56 43 19 40 58* 56
Submerged Gravel Wetland* 83 64 -10 19 81 21 55
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
NOTES:
N/A indicates that the data is not available.
TSS = Total Suspended Solids; TP = Total Phosphorus; Sol P = Soluble Phosphorus;
TN = Total Nitrogen; NO = Nitrate and Nitrite Nitrogen; Cu = Copper; Zn = Zinc
National Pollutant Removal Performance Database, 2nd EditionNational Pollutant Removal Performance Database, 2nd EditionTable 3.1 Median Pollutant Removal (%) of Stormwater Ponds and WetlandsTable 3.1 Median Pollutant Removal (%) of Stormwater Ponds and Wetlands
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/Performance%20Summary%20June%202008.pdf
Low Impact Development Manual for Michigan available at:http://library.semcog.org/InmagicGenie/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
ReferencesReferencesBMP Performance data can be found in;
BMP design information can be found in;
Minimum Treatment VolumeMinimum Treatment Volume
Minimum Treatment Volume
Total Area X 1 inchTotal Area X 1 inchoror
90 percent annual non-exceedance storm and 90 percent annual non-exceedance storm and appropriate runoff model applied to the site.appropriate runoff model applied to the site.
thenthen
Apply BMP or BMPs necessary to achieve 80% Apply BMP or BMPs necessary to achieve 80% reduction of Total Suspended Solidsreduction of Total Suspended Solids
Program Components
Minimum Water Quality Treatment VolumeChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
Channel Protection Criteria:Channel Protection Criteria:
Maintain post-development site runoff volume Maintain post-development site runoff volume and peak flow rate at or below existing levelsand peak flow rate at or below existing levels
All storms up to the 2-year, 24-hour eventAll storms up to the 2-year, 24-hour event
Existing levels = runoff flow volume and rate for the last land use prior to the planned new development or
redevelopment.
Stream StabilityStream 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 it’s watershed.
Channel Protection Criteria
Definition: Bankfull DischargeDefinition: Bankfull DischargeThat discharge which barely That discharge which barely overtops the channel banksovertops the channel banks
Maximum deposition & erosion circulation cell development
Channel Protection Criteria
The most effectivesediment discharge, over time, occurs at the bankfull flow ratewhich is between the 1 to 2 year recurrence interval.
At the bankfull flow,the stream bottom picksup and moves, then redistributes its selfin the same pool &riffle patterns existingprior to the bankfull discharge.
Taken from Rosgen, 1996Channel Protection Criteria
Streams become unstable due to: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
The Channel Protection requirements in the MS4 The Channel Protection requirements in the MS4 Permit address changes in hydrology due to Permit address changes in hydrology due to development and the negative channel responses that development and the negative channel responses that result.result.
Maintaining Predevelopment Maintaining Predevelopment HydrologyHydrology
Time of Concentration (Tc)Time of Concentration (Tc) The time it takes water to get from the farthestThe time it takes water to get from the farthest point in point in
a watershed to a point of collection.a watershed to a point of collection. VolumeVolume
The quantity of water that runs off a site during a The quantity of water that runs off a site during a storm event.storm event.
Peak Flow RatePeak Flow Rate The highest flow rate of a storm event.The highest flow rate of a storm event.
Channel Protection Criteria
Calculates rate and volume of storm runoff using the unithydrograph method for runoff distribution and the curvenumber 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)
24 Hour24 HourPrecipitationPrecipitationRainfall Frequency Atlas of Rainfall Frequency Atlas of
the Midwestthe Midwest, Bulletin 71, , Bulletin 71, Midwestern Climate Center, Midwestern Climate Center,
19921992
Hydrograph for a farm on sandy soil or woods on loamy soil.Hydrograph for a farm on sandy soil or woods on loamy soil.
Qp=23 cfs V=5 acre-ft.
Dave Fongers - DNREChannel Protection Criteria
Loss of infiltration due to development increases total runoff Loss of infiltration due to development increases total runoff volume and peak flows. volume and peak flows.
Qp=23 cfs V=5 acre-ft.
Qp=65 cfs V=11 acre-ft.
Dave Fongers - DNREChannel Protection Criteria
Qp=90 cfs V=11 acre-ft.
Qp=65 cfs V=11 acre-ft.
Qp=23 cfs V=5 acre-ft.
More rapid runoff further increases peak flows. More rapid runoff further increases peak flows.
Dave Fongers - DNREChannel Protection Criteria
Controlling Time of ConcentrationControlling Time of Concentration
Maintain Natural Drainage PathsMaintain Natural Drainage Paths Use open swalesUse open swales Increase surface roughnessIncrease surface roughness Detain flowsDetain flows Minimize disturbanceMinimize disturbance Flatten grades in disturbed areasFlatten grades in disturbed areas Disconnect imperviousnessDisconnect imperviousness Connect pervious and vegetated areasConnect pervious and vegetated areas
Channel Protection Criteria
Runoff Curve Numbers Runoff Curve Numbers For Urban AreasFor Urban Areas
Channel Protection Criteria
MeadowCN = 71
1 Acre Site on C Soils1 Acre Site on C Soils
Paved Commercial Site100% Impervious
CN = 98
Building
Paved Parking
2 year runoff volume = 1640 ft3 2 year runoff volume = 7950 ft3
Runoff Volume to Remove
6310 ft3
Can be accomplishedwith rain gardens on
approximately 20% of site
Channel Protection Criteria
Channel Protection Criteria
2-Year, 24-Hour Rainfall ): 2.42 in
Pre-Development Conditions
Cover Type Soil Area Area S Q Runoff1 Runoff Volume2
Type (sf) (ac) (in) (ft3)
Woods / Meadow A 0 30 23.3 0.2393698 0
Open Space A 0 39 15.6 0.03358739 0
Woods B 0 55 8.2 0.06849468 0
Meadow B 0 58 7.2 0.11496845 0
Open Space B 0 61 6.4 0.17287782 0
Woods C 0 70 4.3 0.41762719 0
Meadow C 43560 1 71 4.1 0.45184657 1640.203047
Open Space C 0 74 3.5 0.56379596 0
Woods D 0 77 3.0 0.6906716 0
Meadow D 0 78 2.8 0.73653831 0
Open Space D 0 80 2.5 0.83402715 0
Impervious N/A 0 98 0.20 2.19122478 0
Other: 0 0
TOTAL: N/A 1.0 N/A N/A N/A 1,640
Post-Development Conditions
Cover Type Soil Area Area S Q Runoff1 Runoff Volume2
Type (sf) (ac) (in) (ft3)
Impervious N/A 43560 1.00 98 0.2 2.19122478 7954.145951
0 0.0 0 0
0 0.0 0 0
0 0.0 0 0
0 0.0 0 0
TOTAL: N/A 1.0 N/A N/A N/A 7,954
Runoff Volume Increase (ft3): 6,314
CN (from TR-55)
CN*
101000
CN SaIP
aIP
)(
2)(
AQ 12/1
Open SpaceCN = 79
1 Acre Site on C Soils1 Acre Site on C Soils
2 year runoff volume = 2847 ft3 2 year runoff volume = 1516 ft3
RunoffVolume Reduction
1331 ft3 Woods CN = 70
Channel Protection Criteria
Channel ProtectionChannel ProtectionDetermine Existing Runoff Volume Using CN MethodDetermine Existing Runoff Volume Using CN Method
thenthen
Determine Proposed Runoff Volume and Subtract Determine Proposed Runoff Volume and Subtract Existing to determine Runoff Volume IncreaseExisting to determine Runoff Volume Increase
thenthen
Apply BMPs to Remove the Runoff Volume Increase Apply BMPs to Remove the Runoff Volume Increase
Channel Protection Criteria
Channel ProtectionChannel Protection
Channel Protection Criteria
• Meeting the Channel Protection Criteria for Meeting the Channel Protection Criteria for Volume Control will also meet the Peak Rate Volume Control will also meet the Peak Rate Control requirement in most cases.Control requirement in most cases.
• For NEW development, meeting the Channel For NEW development, meeting the Channel Protection Criteria for Volume Control will also Protection Criteria for Volume Control will also meet the Minimimum Water Quality Treatment meet the Minimimum Water Quality Treatment Volume criteria in almost all cases. Volume criteria in almost all cases.
Special ConditionsSpecial Conditions
RedevelopmentRedevelopment TransportationTransportation Tight SoilsTight Soils Brown FieldsBrown Fields
Channel Protection Criteria
Permittees are encouraged to discuss Permittees are encouraged to discuss special conditions with District Staff.special conditions with District Staff.
Program Components
Minimum Water Quality Treatment VolumeChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
Permittees shall include a Permittees shall include a requirement that the developer requirement that the developer prepare and implement site plans for prepare and implement site plans for each project subject to the post-each project subject to the post-construction control requirements.construction control requirements.
Site PlansSite Plans Allows the permittee to require and evaluate Allows the permittee to require and evaluate
post-construction control details at the planning post-construction control details at the planning stage.stage.
Sets a foundation for ensuring finished project Sets a foundation for ensuring finished project sufficiently meets post-construction control sufficiently meets post-construction control requirements.requirements.
Permittees should have a checklist or criteria for Permittees should have a checklist or criteria for plan reviewers.plan reviewers.
Site PlansSite Plans
City of Battle Creek—rain garden
Program Components
Minimum Water Quality Treatment VolumeChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
Permittees shall ensure long-term Permittees shall ensure long-term Operation and Maintenance (O&M) plans Operation and Maintenance (O&M) plans for the water quality treatment and channel for the water quality treatment and channel protection controls the permittee requires.protection controls the permittee requires.
O&M RequirementsO&M Requirements
O&M requirements shall beO&M requirements shall beincorporated into the permittee’sincorporated into the permittee’sordinance or regulatoryordinance or regulatorymechanism.mechanism.
Applies to structural and vegetative Best Applies to structural and vegetative Best Management Practices (BMPs), including those Management Practices (BMPs), including those owned or operated by the permittee.owned or operated by the permittee.
Permittees shall review O&M plans and have a Permittees shall review O&M plans and have a tracking mechanism for long-term O&M.tracking mechanism for long-term O&M.
O&M RecommendationsO&M Recommendations
Construction inspections, performance bonds, and Construction inspections, performance bonds, and self-certification processself-certification process
Routine ongoing Routine ongoing inspectionsinspections
Maintenance Maintenance agreementsagreements
Tracking O&MTracking O&M
Program Components
Minimum Water Quality Treatment VolumeChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
The permittee’s ordinance and or regulatory The permittee’s ordinance and or regulatory mechanism is the foundation for implementing mechanism is the foundation for implementing and enforcing the post-construction control and enforcing the post-construction control program.program.
Enforcement MechanismsEnforcement Mechanisms Ordinance and regulatory mechanism contents Ordinance and regulatory mechanism contents
include all of the post-construction program include all of the post-construction program components:components: Treatment Volume StandardTreatment Volume Standard Channel Protection CriteriaChannel Protection Criteria Developer Site Plan RequirementDeveloper Site Plan Requirement Operation and Maintenance RequirementsOperation and Maintenance Requirements Enforcement Mechanisms for Resolving Enforcement Mechanisms for Resolving
NoncomplianceNoncompliance Any Recordkeeping Requirements Any Recordkeeping Requirements Placed on the Placed on the
DeveloperDeveloper
Enforcement MechanismsEnforcement Mechanisms
Resolving noncompliance measures Resolving noncompliance measures include but are not limited to:include but are not limited to: Right of entry for inspectionsRight of entry for inspections Triggers for issuing notices of violationTriggers for issuing notices of violation Authority to require mandatory abatementAuthority to require mandatory abatement Permittee authorization to conduct BMP Permittee authorization to conduct BMP
maintenance and re-coup costsmaintenance and re-coup costs Ability to issue monetary penaltiesAbility to issue monetary penalties
Recordkeeping procedures shall be in Recordkeeping procedures shall be in place to document enforcement of the place to document enforcement of the post-construction control program through post-construction control program through the ordinance or other regulatory the ordinance or other regulatory mechanism.mechanism.
Program Components
Minimum Water Quality Treatment VolumeChannel Protection CriteriaSite Plan RequirementsOperation and Maintenance RequirementsEnforcement MechanismsRecordkeeping Procedures
Recordkeeping RequirementsRecordkeeping Requirements
Copies of post-construction storm water Copies of post-construction storm water control ordinances, regulatory mechanisms, control ordinances, regulatory mechanisms, and any supplemental procedures.and any supplemental procedures.
Applicable records for all development and Applicable records for all development and redevelopment projects required to comply redevelopment projects required to comply with the post-construction program.with the post-construction program.
Recordkeeping RequirementsRecordkeeping Requirements
Developer Site PlanDeveloper Site Plan ChecklistsChecklists CorrespondenceCorrespondence Final approved designFinal approved design
O&M Plans or AgreementsO&M Plans or Agreements Inspection and certification recordsInspection and certification records BMP tracking systemBMP tracking system O&M inspectionsO&M inspections
Enforcement ActionsEnforcement Actions ViolationsViolations Permittee actions to address violationsPermittee actions to address violations