PREPARED UNDER. The 319 Nonpoint Source Pollution Grant Program FUNDED BY. MA Department of Environmental Protection Boston, MA PREPARED BY

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1 PREPARED UNDER The 319 Nonpoint Source Pollution Grant Program FUNDED BY MA Department of Environmental Protection Boston, MA PREPARED BY Vanasse Hangen Brustlin, Inc. Watertown, MA Horsley Witten Group, Inc. Sandwich, MA The Center for Watershed Protection Ellicott City, MD Stacey DePasquale Engineering, Inc. Lawrence, MA

2 Month XX, 2011 Location here

3 Bioretention

4 Off line design Components of Bioretention Pea gravel filter diaphragm Grass buffer strip Ponding area Organic layer (mulch) Planting soil bd bed Plant materials Sand bed Underdrain system Overflow system

5 Bioretention i Schematic Runoff Vegetation on Surface Planting Soil - Primarily Sand Underdrain System

6 Application i of Bioretention i Can be applied to a wide range of development Compatible with commercial landscaping needs Utilizes existing open space Economical for small sites (1 acre or less) Parking lot runoff (perimeters, traffic islands, & swales) Median strips Residential Rain Gardens (roof tops, driveways) Reduce need for storm drain pipe

7 i i or a Rain i Garden? d? Bioretention Bioretention involves: Amended soils; Complex sizing calculations (e.g. modeling); Detailed engineering specifications; Sophisticated conveyance devices (flow splitters, underdrains, overflow inlets, etc). Rain Garden: Generally doesn t involve the above usually a shallow depression in native soils, or modestly amended soils (but might contain some of the above features) Beware off what B h t something thi iis called: ll d O One person s Bioretention is another person s Rain Garden

8 Successful LID Design & Implementation It doesn t tjust thappen (several factors must be considered): Site Selection and identification Soils and depth to groundwater matter; Topography (slope, available head) limits; Drainage area is a factor; Land use and density drives design; Managementobjectives limitpractice alternatives Management objectives limit practice alternatives (recharge, water quality vs. quantity, target pollutants)

9 Successful LID Design & Implementation (Cont.) Pretreatment is critical; Practices must be sized correctly; Conveyance to a practice matters; Filtration media must be correct; Landscaping doesn t just happen; Maintenance is also a must; Erosion and sediment control during construction; and Community/environmental concerns must be addressed.

10 Bioretention i Sizing ii Design Volume sized for 75% of WQv Pretreatment sizing based on particle settling design (Camp Hazen Eq) A s = Q/W*ln(1 E) Pretreatment provided by: Grass filter strip below a level spreader or grass channel Gravel diaphragm Mulch hlayer Treatment sizing based on Massachusetts Stormwater Standard (5% to 7% of the drainage area);

11 Design Notes Pretreatment essential (25% WQv) Sized for temporarily holding at least 75% of WQv, including pretreatment 6 9 ponding above surface Typically, 2 4 planting soil bed (30 min. for TN removal) Use a conservative permeability coefficient Specific engineered soil media Detailed landscape plan

12 Lots of Different Materials il

13 Equipment List Backhoe/Excavator (note mini excavator) Front End Loader Dump Trucks Pumps/compactors/saws/etc. Shovels/Rakes/Wheelbarrows Roto tillers

14 Basic Materials il for Bioretention i 1. Inlet Structures 2. Outlet tstructurest 3. Filter Bed Gravel Underdrain Jacket Underdrain Pipe and Cleanout Filter Fabric Impermeable Liner (possible) Pea Gravel Filter Media Mulch 4. Pretreatment Forebay Structure 5. Plantings Plants (tolerant of wet and dry conditions) Watering 6. Other Loam/Erosion Control lblanket (side slopes) Grass Seed/Sod Landscape Stone/Riprap p Chambers

15 Evaluate Inlet Conditions i How will the stormwater runoff enter the facility? Extended downspout/gutter Stone or concrete spillway Across lawn via a gradual slope Vegetated or stone lined swales Paved surface Diversion berm along the bottom of slope

16 Evaluate Inlet Conditions (Cont.)

17 Inflow Structures

18 Flow Diversion Structure To Water Wt Quality Facility Bypass Pipe

19 Inlet Structure HDPE Pipe with flared end section Riprap or landscape stone p p p apron

20 Outlet Structure Fiberglass Nyloplast (ADS, Typically 24 Diameter with Inc.) catch thbasin structures t main outlet t and 1 to 2 With frame and grate underdrain inlets

21 Outlet Structure (Cont.)

22 Filter Bed Materials il

23 Gravel (Underdrains d and Storage) AASHTO M 43 standard Washed, clean, and open graded Size varies ASTM # 2 or 3 Stone (<2 to2 ½ ) ASTM #57 Stone (<1½ ) ASTM #8 (1 2 )

24 Underdrain d Pipe Cleanout Rigid schedule 40 PVC pipe with 3/8 6 O.C. meeting ASTM D 1785 T s and Y s as needed depending upon the underdrain configuration

25 Underdrain d Cleanout Non perforated rigid schedule 40 PVC pipe with 3/8 6 OC O.C. meeting ASTM D 1785 PVC elbow, cap and all associated fittings

26 Filter Fabric bi Non woven geotextile fabric with a flow rate of > 110 gal./min./sf. F h d d i d For use over the underdrain and along the side walls

27 Impermeable Liners 30MIL PVC impermeable liner: Specific Gravity (ASTM D 792): 120 (min.) Tensile (ASTM D 882): 73 (lb/in width, min) Elongation at Break (ASTM D 882): 380 (% min.) Modulus (ASTM D 882): 30 (lb/in width, min) Tear Resistance (ASTM D 1004): 30 (lb/in min.) Bentonite Clay Bentonite shall be a free flowing, high swelling, granular sodium bentonite

28 Pea Gravel 3/8 Washed stone Between the bioretention soil layer and approved sub grade or underdrain gravel

29 Bioretention i Soil Mix USDA soil type loamy sand or sandy loam Filter Media to contain: 40% sand 20 30% topsoil 30 40% compost Clay content should not exceed 5% See Massachusetts Stormwater See Massachusetts Stormwater Water Standards, Volume 2, Chapter 2, Page 26 for more details

30 Bioretention i Lab Testing Textural analysis is required from the site stockpiled topsoil. If topsoil is imported, then a texture analysis shall be performed for each location where the top soil was excavated. Minimum requirements: See Massachusetts Stormwater Water Standards, Volume 2, Chapter 2, Page 26 for more details Soilshall be a uniform mix,free of stones, stumps, rootsorother Soil shall be a uniform mix, free of stones, stumps, roots or other similar objects larger than one inch. Consult the bio construction specs.

31 Infiltration i Testing Summary Infiltration Practice: 1 soil sample for every 5,000 ft of basin area is recommended, with a minimum of 3 samples for each infiltration basin. Samples should be taken at the actual location of the proposed infiltration basin. Fitration Practice: Infiltration testing not strictly required, however depth to seasonal high groundwater or bedrock is required.

32 The Benefits of Mulch: Mulch lh Keeps soil moist, which allows for percolation of rain water Protects plants and makes weeding easier Minimizes erosion of the rain garden soil Mulch Quantity: Amount of Mulch Required for a Three Inch Thick Layer Size of Facility Approximate Amount of Mulch 25 square feet 0.25cubic yard 50 square feet 0.50 cubic yard 100 square feet 1.0 cubic yard 200 square feet 2.0 cubic yards

33 Mulch lh( (Cont.) Fine shredded well aged (6 month min.) hardwood mulch A finely shredded, well aged, organic dark pine mulch may be acceptable Sample submitted to design engineer for approval, if applicable Do not used dyed or color treated mulches

34 Other Design Considerations i Erosion Potential ti Will the velocity and erosion of the stormwater runoff be a problem? Erosion is possible. Address with: Grading Rocks/obstructions to slow flow Rocks to stabilize Erosion control blanket Photo Credit: RCE of Monmouth County

35 Evaluate Overflow Where will the excess stormwater runoff go in a heavy storm event? Overflow is away from structures Berm higher near building Overflow sheetflow Gloucester County 4-H Fairgrounds Flows onto street an existing storm drain can be used as an outlet

36 LID Practices Conveyance Non erosive overflow velocities (3.5 to 5 fps) Full infiltration within 48 hours Designedas off line ifconveyed withinsdsystem Overflow provided for 10 year Storm Overflow surcharge pipe on dry wells

37 Landscaping

38 Landscape General Guidelines Drainage area completely stabilized prior to bringing facility on line Landscaping plan required for bioretention facilities: Planted with native species over non native (some exceptions) Plants specified based on tolerance to wet/dry conditions Provide a variety of trees, shrubs, herbaceous materials No woody vegetation at inflow locations Trees alongthe perimeter of the facility (tree density at 10 centers, shrubs at 5 centers, herbaceous plants at 2 centers)

39 Determine Plant Quantity Approximate Amount of Plants Based on Future Mature Size Size of Facility Approximate Amount of Plants 100 square feet 1 Small Tree (Optional) 7 Shrubs 24 Herbaceous Species 200 square feet 1 Small Tree (Optional) 14 Shrubs 48 Herbaceous Species Leonard Park, Morris County NJ

40 Planting Zones

41 Planting Plan

42

43 O&M

44 Bioretention i Maintenance Remove sediment from pretreatment when depth exceeds ½ design depth, clean/repair when drawdown exceeds 36 hours; Remove sediment from filter bed when depth exceeds 1, rehabilitate bed if standing water is present 48 hours after a storm (roto till or aerate); Refurbish mulch every other year (tillexisting materialsinto into soil) as needed; Vegetative maintenance; Repair erosion gullies; and Repair structural components.

45 Weeding Do not use chemical herbicides Remove by hand Be on the lookout for invasive species: Photo by Betty Ann Kelly Japanese Knotweed Oriental Bittersweet

46 Replace dead or diseased plant material Place plant in the same location Re seed the side slopes Plant Replacement Best time to replant: Early to mid Fall Early to mid Spring Photo courtesy of Rutgers New Jersey Agricultural Experiment Station

47 Landscape boulders add interest Mix and match plants Pay attention to bloom time and color Plant Design Consider Fall/Winter interest

48 Questions?

49 CONTACT INFORMATION Bethany E. Eisenberg Director of Stormwater Services VHB Vanasse Hangen Brustlin, Inc. 101 Walnut Street Watertown, MA Phone: x1229 Fax: Direct: Richard A. Claytor, Jr., P.E. Principal Engineer Horsley Witten Group 90 Route 6A, Sandwich, MA Deb Caraco Center for Watershed Protection Field ldoffice: 606 N. Aurora St., Ithaca, NY Main Office: 8390 Main Street, 2nd Floor, Ellicott City, MD Stacey A. DePasquale, P.E. President SDE 354 Merrimack kstreet, Suite 200 Lawrence, MA inc.com inc.com/