Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 1 Low Impact Development and Stormwater Management in Pennsylvania Robert G. Traver, Ph.D., PE Department of Civil and Environmental Engineering Director, Villanova Urban Stormwater Partnership II. Stormwater Management in Pennsylvania

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 2 Outline  Definitions  Pa Stormwater Management History  Why the Change?  Current Pa Stormwater Requirements.

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 3 Development and the Hydrologic Cycle Thanks to MDE Original from MDE

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 4 Definitions: Objectives of SWM  Protecting Life & lessening Public Health & Safety Risk  Reducing Risk of Monetary Damage to Private / Public Property  Minimize disruption of Community Affairs  Protecting Quality of Surface and Groundwater  Enhancement of the Quality of Life in Urban Areas –ASCE Stormwater Manual of Practice

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 5  ASCE Code of Ethics –Engineers shall hold paramount the safety, health, and welfare of the public and shall strive to comply with the principles of sustainable development in the performance of their professional duties – (ASCE 2002)

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 6 Definitions - Flooding  Natural - every 2 years out of channel….  Multiple Causes –Rains too hard –drainage system inadequate –urbanization increases volume / risk  opposite… drought?

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 7 “Risk” - Definition  Return Period (T) –Rainfall event equaled or exceeded over a year –T = 1/P x year storm ~ 50% (P) – 100 ~~~~~~ 1%  Risk = 1-(1-P)^n

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 8 Definitions - Floodplain & Stormwater Management Definitions - Floodplain & Stormwater Management  Distinction Between - Large vs. Small Sites? –Both Required by Regulation  Degree? Agency? –Floodplain – River –Stormwater - Watershed –Stormwater - Growing Quality Orientation –Flood Plain - Protection –higher priority  Similarities –Life & Safety –Public Interest Intense - but brief & Infrequent –Coming together!  Similar structural / nonstructural measures  Similar Design Tools - same methods, different orientation  Same System

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 9 Pa SWM - Historically Based on……..   Groundwater Rich   Concern over Peak Flows / Flooding (property damage)   Channel Stability (Cost)   “Drainage”   Pics from MDE (except as noted)

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II – PA ACT 167  Peak Flows Limited to Preconstruction Levels  All Points Leaving Site  Municipal Implementation

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II FOCUS  Peak Flows  Large Storms (100 Yr?)  Individual Sites –“downstream property line” –Detention Basins

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 12 From old Design Manual

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 13 Storm Hydrograph Pre Post Post W/ SWM

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II RESULTS  Flow Collected and Concentrated  Detention Basins –BIG –Bottom of Site Traver 1978

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II Results Post Pre Time Flow Post w/ SWM basin Lost Infiltration Increased Channel Erosion

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II CONCERNS  Effect of Small Storms on Downstream Channels  Downstream Effects of Basins –Combination  Ownership? Maintenance?

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 17 ASCE Journal of Hydraulics  Nov 1979 – “Downstream Effects of Stormwater Management Basins” – Richard McCuen –It is recognized that the urbanization process is responsible for increases in both runoff flow rates and sediment volumes…. The question that has led to much consideration is: Are SWM Basins effectively meeting the intent of stormwater management?”

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II ACT 167 REVISED!  Enabled Watershed Planning –plans revised every five years –considers existing trouble areas –usually developed by county  Peak Flows – limited to preconstruction levels – limited by effect on Watershed  Municipal Implementation

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II FOCUS  Peak Flows  2 ~ 100 Year Storms  Watershed Drainage System –Release Rate

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II RESULTS  Flow Collected and Concentrated  Bigger Detention Basins –2 ~ 100 year storms –Release Rate ~ Watershed Location  Owned –Homeowners Associations –Municipal

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 21 Issues

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 22 Act 167 Status Dec PaDEP

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 23

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 24

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 25 EPA Region III Website

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 26 ASCE Journal of Hydraulics  April 1980 – “Stormwater Detention in Developing Watersheds” – C Amandes, P. Bedient –Urban Stormwater runoff has become the major source of stream pollution in many urban areas as point source effluents have been largely controlled through improved treatment.  July 1988 – “Multicriterion Stormwater Management Methods” – R. McCuen & G. Moglen –Both theory and experience indicate that, while detention basins designed to control peak discharge are effective in controlling the peak rates, the basins are ineffective in in controlling the degradatation of erodible channels downstream of the basin.

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 27 What do we design for?

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 28 The “old” way- directly connected Roof Driveway Street Inlet Culvert Post Infiltration -- Decreased Baseflow -- Decreased Groundwater Recharge -- Decreased Runoff Quality-- Decreased Stream Bank Erosion -- Increased Runoff Speed-- Increased Peak Flows-- Increased Volume -- Increased No Chance to Infiltrate No Pollutant Filtration

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 29 Pa Comprehensive Stormwater Policy  Protect and maintain stream uses/water quality;  Protect, maintain and sustain water quantity; and  Integrate federal stormwater management requirements. “”  Integrate federal stormwater management requirements. “NPDES – II”  Best Management Practice (BMP) approach to stormwater management that emphasizes groundwater recharge and the reduction of impacts from discharges to surface water. PaDEP Aug 2002

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 30 Comprehensive Stormwater Management Program Pa SW Mgt Symposium Villanova University October 16,2003 Durla Lathia, P.E. Bureau of Watershed Management Pa DEP The following slides are excerpts from a presentation Durla Lathia PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 31 DEP’s Initiative For Public Input for New Directions  15 Water Forums held in 2001  Public Identified Stormwater Management as a Consistent Issue, and Wanted a Comprehensive Implementation of Various Water Management Programs PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 32 “…..to improve and sustain ground and surface water quality and quantity …… Pennsylvania’s Comprehensive Stormwater Management Policy GOAL: September Direct Link to “Stormwater” PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 33 Under what authority was the policy issued? Comprehensive SW Policy Antidegradation Requirements Section 93.4a Existing In-Stream Water Uses and the Level of Water Quality Necessary to Protect the Existing Uses Shall Be Maintained and Protected The Water Quality of High Quality & Exceptional Value Waters Shall Be Maintained & Protected PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 34 Implementation Goals To successfully implement the Comprehensive Stormwater Management Policy the goals must: To successfully implement the Comprehensive Stormwater Management Policy the goals must:  Be reasonably attainable  Target and prioritize major obstacles  Be effectively implemented utilizing existing resources PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 35 Comprehensive Stormwater Management Approach  Integration of Planning, Technical and Regulatory Programs  Financial Incentives  Provide Necessary Technical Tools and Support – BMP Tech Manual PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 36 COMPREHENSIVE SW POLICY Special Protection Waters NPDES Construction Permits NPDES Phase II MS4 Permits ACT 167 Planning Program PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 37 NPDES Construction Permits  P ermits require protection of uses and maintenance of water quality – E/S Control Plan to minimize pollutants from earth disturbance activities. – Post Construction SW Mgt. Plan  Permits now emphasize requirement for PCSM Plans  Identification, Assurance for Operation and Maintenance of BMPs – Preparedness, Prevention, Contingency Plan PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 38 PCSM PLANS Must Accompany Permit Application Identifiy BMP’s BMP’s MUST be Designed and Constructed in accordance with: DEP Approved Act 167 SW Plan with Water Quality Requirements, if a Plan Exist, Existing MS4 Municipal Ordinance, IF No Act 167 SW Plan, A 2-Year - 24 Hour Runoff Volume Difference Management (Post - Pre Development Conditions), If neither Act 167 nor MS4 Municipal Ordinance exists. A Long Term Maintenance of BMP’s is Required PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 39 Act 167 Stormwater Planning Program  Incorporates hydrologic and hydraulic Evaluation of a Watershed for Existing and Future Land Use Scenario  Requires County and Municipal participation  Considers Existing Local Regulatory Programs  Recommends Control of Stormwater Runoff from Development Activities  A Recommended Model Ordinance PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 40 NPDES Phase II MS4 Program  “Municipal Separate Storm Sewer System (MS4)”  20 Urbanized Areas  929 municipalities, 30 counties, 14 potential municipalities, plus state and federal institutions (PADOT, PTC, prisons, universities)  Permit Requires Implementation of 6 Minimum Control Measures –Public Education –Public Participation & Involvement –Illicit Discharges –Construction –Post-construction –Pollution Prevention/Good Housekeeping PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 41 NPDES II-MS4 Permit  For General Permits, MS4s have Two options: –Follow DEP “SW MGT. PROTOCOL”  “Pre-approved” Tasks  Relaxed deadlines for Multi-municipal Efforts, Working on Watershed Based Approach  Funding Opportunity, if Act 167 Planning is Involved Or –Develop own program  Must get DEP approval  No funding PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 42 Expanded Scope of Act 167 Program  In addition to the requirements of the Section 5(b) of the Act, ALL Minimum Control Measures of the NPDES MS4 Permit requirements may be included in a SW Plan, if Counties and Municipalities wish to do so  Funding is also included for the expanded scope PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 43 Act 167 SW Management Planning Rate & Volume Control Water Quality NPDES MS4 Permit Special Protection Waters Infiltration Groundwater Recharge Tailored Municipal Ordinances NPDES Construction Permit Financial Assistance Technical Assistance PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 44 How Does Act 167 SW Planning Implement Comp SW Policy???  Recommend Measures and Techniques to Address Stormwater Runoff Impact with a Goal to Mimic Pre-Development Conditions after Development is Completed.  Control Standards for Quantity, Quality,Groundwater Recharge and Stream Protection  NPDES Regulatory Components Included PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 45 Act 167 SW Planning Status  85 Plans approved for 47 counties  Plans approved after Aug contain WQ Components  777 Municipalities to enact and implement ordinances  42 additional Plans currently under way ( 23 Counties, 603 Municipalities): All Plans have WQ Components PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 46 STORMWATER ORDINANCE  MS4 Ordinance(available on DEP Website)  A General SW Ordinance which includes all the components of Stormwater Management. Counties include this ordinance in their SW Plans, subject to watershed specific modifications. Municipalities, not part of a SW Plan, are encouraged to consider adoption PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 47 Pa BMP Technical Manual  Tech Manual to Provide Computational Procedures and Specifications- It will NOT Be a Regulatory Handbook  18 Month Project  Consultant Has Been Selected  Oversight Committee Members Appointed  First Oversight Committee Meeting Held on October 10, 2003  DEP Contacts: Dennis Stum/Ken Reisinger PaDEP Presentation – Pa SWM Symposium Oct 2003

Low Impact Development and Stormwater Management in Pennsylvania Villanova Urban Stormwater Partnership – II 48 Stormwater Management How Can We Help ?? Central Office Regional Offices Direct Link to “Stormwater” PaDEP Presentation – Pa SWM Symposium Oct 2003