6/4/2014 SHRINKING THE FOOTPRINT FOR EFFECTIVE STORMWATER MANAGEMENT OVERVIEW REGULATIONS

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1 SHRINKING THE FOOTPRINT FOR EFFECTIVE STORMWATER MANAGEMENT Sandy Camargo, PE Advanced Drainage Systems 2014 KSPE Convention May OVERVIEW Regulatory Drivers Stormwater Management Considerations Underground Detention 101 Underground Detention Applications REGULATIONS Like your mother-in-law Not going away unless you divorce yourself from the situation Learn to live with her or spend your life in misery Continuously evolving and becoming more stringent Don t always make a lot of sense but we adapt because we have to 1

2 A LOT HAS CHANGED IN 3000 YEARS The Roman aqueducts; a running water and sewer system that carried disease away from the empire EARLY CONVEYANCE Wood pipe systems in London have been found that date back to the 13 th century. Remarkably, the City of Philadelphia also claims to still have wood pipe in service. UNREGULATED STORMWATER MANAGEMENT Driven by NEED Need for drinking water Need for navigation Need to protect from flooding Need to provide good crop land Need for personal hygiene Need to flush away waste Need for a good fishing hole! 2

3 AHH, THE CLEAN WATER ACT 1972 Federal Water Pollution Control Act 1977 Clean Water Act the follow up to the prior The Clean Water Act of 1977 maintains the original promise of the clean water for the American people. More than seventy changes were made in the existing law. Most enhance the ability of the Administrator of the Environmental Protection Agency to deal with complex water pollution problems. We made some requirements more flexible, but we have not strayed from our basic goals. We have maintained our goal to eliminate the discharge of pollutants by We have maintained the policy that the public must be protected from cancer-causing pollutants and other toxic poisons. We have maintained the concept that industry must use the best available technology to control pollution. We have renewed our commitment to provide adequate funding to publicly-owned treatment plants. Edmund Muskie, EPA Journal July/August YEARS LATER ENTER NPDES Phase I communities large cities Individual permits negotiated with state and federal agencies 5 year permit cycles Phase II communities 10,000 population and minimum population density (and many other hooks should DOW or EPA choose to cast the line out) General 5 year permit covering all communities Communities must develop a 5 year Stormwater Quality Management Plan, SWQMP, to meet permit compliance EPA GOALS AND NEW PERMIT CYCLES Monitoring for Phase II MS4s TMDL enforcement window Maintenance and performance documentation Grace Period is definitely over More and more push for on-site management and volume reduction Green-LID-Natural-Infiltration-Pervious Permeable-Treatment Train -Evapotranspiration 3

4 OLD SCHOOL STORMWATER MANAGEMENT Identify it Collect it Route it Forget it OLD SCHOOL PROBLEM NEXT STAGE OF PROGRESS Identify it Collect it Detain it Match Peak Route it Forget it 4

5 NEXT STAGE PROBLEM STREAMS BEAR THE BRUNT OF FORGET IT Impervious Cover #TRENDING Water QUALITY requirements Volume reduction Mimicking the pre-developed hydrology Overall site integration Creative design and planning Cumulative effects of many practices to meet requirements Of course cost effective because land and materials aren t getting any cheaper 5

6 Hydrograpgh Pre/ Post Development Courtesy Larry Coffman Developed Condition, Conventional CN (Higher Peak, More Volume, and Earlier Peak Time) Q Existing Condition T Detention Peak Shaving Developed Q Developed Condition, with Conventional CN and Controls Existing Peak Runoff Rate Additional Runoff Volume Existing T Developed- No Controls Reduced Q p Developed Condition, with LID- CN no Controls. Reduced Runoff Volume Minimize Change in Curve Number Q Existing T 6

7 Developed, LID-CN no controls Reduced Q p Maintain Time of Concentration Q Developed, LID- CN no controls same Tc as existing condition. More Runoff Volume than the existing condition. Existing T Reducing Volume Q Provide Retention storage so that the runoff volume will be the same as Predevelopment A 1 Retention storage needed to reduce the CN to the existing condition = A 2 + A 3 A 2 A 3 T Detention Storage Q Provide additional detention storage to reduce peak discharge to be equal to that of the existing condition. Predevelopment Peak Discharge Existing T 7

8 Comparison of Hydrographs Q Increased Volume w/ Conventional Conventional Controls LID Concepts A 2 A3 T Existing Hydrograph Summary 1 Existing 2 Developed, conventional CN, no control. 3 Developed, conventional CN and control. 4 Developed, LID-CN, no control. Q Pre-development Peak Runoff Rate Developed, LID-CN, same Tc. Developed, LID-CN, same Tc, same CN with retention. Same as 6, with additional detention to maintain Q T CONVENTIONAL SITE DESIGN Each component is separate from the others and needs its own space Building Parking Transit (walk, bike) Drainage Water quality Detention Landscaping 8

9 CONVENTIONAL SITE DESIGN Horizontal thinking plan view 2D The biggest driver for stormwater management IMPERVIOUS SURFACE Higher runoff rate Higher runoff volume More pollutant conveyance Higher stormwater management fees! More costly Land Construction Life cycle OPPORTUNITIES TO SHRINK FOOTPRINT Planning code revisions or variances Mixed use Cluster development Skinny streets No curb and gutter Provides the opportunity to reduce impervious cover Lowers rate and volume of runoff Lowers user fee - less ERUs 9

10 CLUSTER DEVELOPMENT OPPORTUNITIES - LID Reduced impervious from some Green roof Permeable pavements, walks Volume reduction from most in varying degrees Capture and Infiltration Evapotranspiration Rain gardens, bioswales, green roof, permeable pavement Treatment from all Likely to still need some detention for more peak reduction & storage volume something is missing BAM - ANOTHER NOTCH! Underground Detention! Enhance what you have Take advantage of the vertical space 3D Can handle increased site impervious area Very flexible can conform to most sites Treatment with some systems Infiltration with some systems 10

11 UNDERGROUND DETENTION Storage detention infiltration - treatment with no footprint!! Stealth BMP BASICS OF UNDERGROUND DETENTION Types of systems FUNCTION 11

12 How Does It Work? Storm Sewer Isolator Row Outlet CROSS SECTION - STORAGE Volumetric Reduction CREATE SURFACE AREA FOR INFILTRATION TO OCCUR UNDERGROUND DETENTION PROVIDES NECESSARY VOLUME (AND TIME) FOR INFILTRATION 12

13 Volumetric Reduction TOTAL Infiltration Volumetric Reduction Inlet Outlet Infiltration for Water Quality TREATMENT - EXTERNAL Manhole type Pretreatment typical 13

14 TREATMENT - EXTERNAL Vault type Pretreatment typical TREATMENT - EXTERNAL Filter Type TREATMENT - INTERNAL 14

15 APPLICATIONS Large sites Small sites Flexible design LINEAR APPLICATIONS BIOSWALE INFILTRATION TRENCH 15

16 HYBRID DITCH RAIN GARDENS MODIFIED SIDEWALK 16

17 LARGER BED APPLICATIONS PARK APPLICATION BIORETENTION 17

18 RETROFIT PARKING DOWNSPOUT DISCONNECTON CASE STUDY RONALD MCDONALD HOUSE 18

19 WHAT S THE DRIVER? IMPERVIOUS COMBINATION OF PRACTICES Underground detention Permeable pavements Rainwater harvesting Rain gardens SUMMARY Regulations will continue to ask for more, with meeting pre-development conditions a goal Impervious surface increases costs in many ways Site design needs to blend components, concepts and BMPs creative thinking Underground detention is the hidden gem to meet water quality and quantity requirements without requiring any additional footprint Are you ready to go underground? 19

20 QUESTIONS? Sandy Camargo Advanced Drainage Systems (ADS)