Rain Garden Site Selection, Installation & Plant Selection Pinelands Short Course March 26, 2011 Knezik Rutgers CooperativeRutgersExtension Don CurtisHelm

Mike Haberland Environmental and Resource Management Agent Rutgers Cooperative Extension of Burlington & Camden Counties Phone: 856-566-2914 Email: [email protected] Stormwater 101 Where does precipitation go?

It can infiltrate through the soil surface and percolate downward to groundwater aquifers

Courtesy of Texas Watershed Stewards, Texas A&M AgriLife Extension Stormwater 101 WHAT IS A RAIN GARDEN?

• A rain garden is a landscaped, shallow depression that captures, filters, and infiltrates stormwater runoff. • The rain garden removes nonpoint source pollutants from stormwater runoff while recharging groundwater.

“Nonpoint source pollution” is also called “people pollution.” It is the pollution that comes from our everyday lives. It is the fertilizers that wash off our farms and lawns. It is the pet waste that washes into our streams. It is the sediment (or soil) that erodes from our lands into our local waterways. It is the oil and grease that comes from our parking lots. Finally, it is the pollutants such as nitrogen, phosphorous, and heavy metals that settle out of our atmosphere onto our roads and rooftops. When it rains, the stormwater runoff carries nonpoint source pollution and may ultimately wash it to our waterways. Stormwater 101 What is a Rain Garden?

• A shallow landscaped depression designed to intercept, treat, and infiltrate stormwater at the source before it becomes runoff.

• The rain garden removes nonpoint source pollutants from stormwater runoff while recharging groundwater.

• Designed to merge two important goals: aesthetics and water quality.

• Can be blended into the landscape and made to look natural. Stormwater 101 The Science Behind Rain Gardens

• Absorption to soil particles − Removes dissolved metals and soluble phosphorus

• Plant uptake − Removes small amounts of nutrients

NOTE: 90% of all storm events • Microbial processes produce less than 1 inch of rain. − Removes organics and pathogens Therefore, the key to reducing pollutant loads is to treat the runoff associated with the first 1 • Exposure to sunlight and dryness inch of rain (Clayton & Schueler, − Removes pathogens 1996).

• Sedimentation and filtration − Removes total suspended solids, floating debris, trash, soil-bound phosphorus, some soil-bound pathogens

• Infiltration of runoff − Provides flood control, groundwater recharge, and nutrient removal Rain Garden Site Selection and Installation Steps 3. Maintenance

2. Installation

1. Planning

Mendham Township Elementary School, Morris County PARTS OF A RAIN GARDEStormwaterN 101 Stormwater 101 UNDERSTANDING YOUR PROPERTY

• How does rainwater flow through your yard? • Where does the runoff travel to once it leaves your yard?

ROOF

PLACE A RAIN GARDEN BETWEEN TWO IMPERVIOUS SURFACES REDUCE THE AMOUNT OF RUNOFF ENTERING STORM SEWERS

ROAD Stormwater 101

Image Courtesy of the City of Maplewood, MN Stormwater 101 Rain Garden Placement

Things to Remember

• The rain garden should be at least 10 feet from the house so infiltrating water doesn’t seep into the foundation. • Do not place the rain garden within 25 feet of a septic system. • Do not put rain garden in places where the water already ponds or the lawn is always soggy. Rain garden soils must drain well ! • Place in full or partial sunlight as a first option • Select a flat part of the yard for easier digging as a first option. • Avoid large tree roots. No closer than tree drip line.

http://clean-water.uwex.edu/pubs/raingarden/rgmanual.pdf Stormwater 101 Planning Steps Site Visit

Determine Current Stormwater Flow

Flow If the area is prone to flooding, it may be difficult to improve the drainage.

Union County Vocational School Stormwater 101 Planning Steps Site Visit

Take Photographs Stormwater 101 Identify the Drainage Area - Rooftop Scenario

Surface area = (L1 x W ) + (L2 x W) = (15’ x 20’) + (10’ x 20’) = 300 ft2 + 200 ft2 = 500 ft2

Roof 1 Roof 2

Length Width

Possible Rain Garden

Hockman Farm, Winchester, Virginia Stormwater 101 DRAINAGE AREA: THE ROOFTOP SCENARIO Stormwater 101 Parking Lot/Driveway

Make observations during storms to estimate the drainage area

Drainage Area Stormwater 101 Correspond Drainage Area to Rain Garden Size

Rain Garden Sizing Table Based on New Jersey’s Water Quality Design Storm of 1.25 inches

Drainage Size of 3” Deep Size of 6” Deep Size of 8” Deep Area Rain Garden Rain Garden Rain Garden 500 ft2 200 ft2 100 ft2 75 ft2 750 ft2 300 ft2 150 ft2 112 ft2 1000 ft2 400 ft2 200 ft2 149 ft2 1500 ft2 600 ft2 300 ft2 224 ft2 2000 ft2 800 ft2 400 ft2 299 ft2

The size of the rain garden is dependent upon the amount of runoff entering the rain garden Stormwater 101 Parking Lot /Driveway Runoff

Before After

Union County Vocational School Road, Driveway,Stormwater or 101 Parking Lot Scenario With a curb (curb cut needed)

Photo Credit: Barr Engineering, Minneapolis, MN Correspond Percent SStormwaterlope to 101 Rain Garden Depth

Percent Slope Typical Depth ≤ 4% 3”-5” 5% - 7% 6”-7” 8% - 12% 8” maximum depth > 12% Consider another location

Exception: Sites with poor percolation or high percentage of clay soils will be shallower with a larger surface area since they percolate slowly. Stormwater 101 Determine Slope

Slope = _H_ x 100 = _6”_ = _0.5’_ x 100 = 5% slope W 10’ 10’ Stormwater 101 Calculate Size of Rain Garden

[Drainage Area (square feet) x NJ’s Water Quality Design Storm (feet)] Size of = [Rain Garden Depth (feet)] Rain Garden (square feet)

Rooftop #1: Length = 12’ Rooftop # 1 Width = 28’ CHEAT SHEET L x W = 336 sq ft NJ’s Water Quality Design Storm = 1.25” = 0.1’ Rooftop # 2 Rooftop #2: Length = 12’ Rain Garden Depth:  3” = 0.25’ Width = 14’  6” = 0.50’ L x W = 168 sq ft  8” = 0.67’ % Slope = 6% What is the depth and square footage of the Proposed proposed rain garden? Rain Garden 2 [504 ft x 0.1’] = 101 ft2 rain garden [0.50’] 6” deep Stormwater 101 Check Your Soil

• Soil Texture Test Roll soil into a ball in hand and see how it forms • Hard ball – Clay/Silt soil • Soft ball – Loamy soil • No ball – Sandy soil

• Sample the soil and send to the Rutgers Soil Testing Lab for: • Nutrient analysis/ recommendations ($20) • pH analysis/ recommendations • Percent sand/ silt/ clay ($30) Stormwater 101 Check Your Soil Drainage

Infiltration/Percolation Test

1. Dig a hole in the proposed rain garden site (12” deep, 4-6” wide).

2. Fill with water to saturate soil and then let stand until all the water has drained into the soil.

3. Once water has drained, refill the empty hole again with water so that the water level is about 1” from the top of the hole.

4. Check depth of water with a ruler every hour for at least 4 hours.

5. Calculate how many inches of water drained per hour.

Want at least ½” per hour percolation. Garden should drain within 24 hours. Stormwater 101

Rain Garden Should Drain Within 24 hr Stormwater 101 Determine Existing Utility Lines

CALL BEFORE YOU DIG

• Free markout of underground gas, water, sewer, cable, telephone, and electric utility lines • Call at least 3 full working days, but not more than 10 days, prior to planned installation date • Do not place rain garden within 5’ horizontally and 1’ vertically from any utilities Stormwater 101

INSTALLING YOUR RAIN GARDEN Stormwater 101 Tools and Materials

MATERIALS NEEDED TOOLS NEEDED

• Soil amendments (if necessary) • Work crew (5-10 people) – Fertilizer • Back hoe or bobcat (optional) – pH adjustment (lime) • Shovels (flat and round) – Coarse sand (bank run) • Vegetation • Yard rakes (to spread soil & mulch) • Triple-shredded hardwood mulch • Rototiller ($500 - $1,000 investment, (no dye) or rent one) • Soaker hose & landscaping pins • Survey equipment or string level with stakes and mason string • Optional – Decorative stone/ pavers • Knives to cut root balls – Landscaping fabric & pins • Hand trowels – Pipe extensions • Wheelbarrows – Grass seed/sod

Leonard Park, Morris County Hurffville Elementary School, Gloucester County Stormwater 101 Installation Steps

• Remove existing grass • Excavate to the desired depth • Add soil amendments • Prepare the berm • Prepare the overflow • Level the ponding area • Plant the vegetation • Apply the mulch • Water the vegetation Stormwater 101 Remove Existing Grass

Using backhoe

By hand Stormwater 101 Excavate to the Desired Depth

Level the Ponding Area

Leonard Park, Morris County Gloucester County 4-H Fairgrounds Stormwater 101 Depth of the Rain Garden

• Depth of rain garden is dependent upon the soil texture found at the site of the rain garden • Depth is usually 3-8 inches Stormwater 101 Prepare the Berm, if necessary Stormwater 101 Add Soil Amendments, If Necessary

Mix in with rake or rototiller

Gloucester County 4-H Fairgrounds Stormwater 101 DETERMINING THE INLET AND OVERFLOW

• Stormwater runoff enters the rain garden from an inlet. • Stormwater exits through the overflow.

Small yard drain can connect to existing underground drain pipe.

Cherry Hill Department of Public Works, Cherry Hill, New Jersey Stormwater 101 Determine Rain Garden Inlet

How will the stormwater runoff enter the rain garden?

• Extended downspout/gutter • Stone or concrete spillway • Diversion berm along the bottom of slope • Across lawn via a gradual slope • Vegetated or stone-lined swales •Paved surface Slow Down the Speed ofStormwater Water 101 Entering the Garden

• Attach a perforated plastic diffuser to the end of your gutter/ downspout

• Use river rock at the entrance point of the rain garden

• Site your rain garden within a grass buffer between the garden and the gutter/downspout. Use native grasses and let them grow tall. Stormwater 101 Determine Rain Garden Overflow

Where will the excess stormwater runoff go in a heavy storm event?

• Overflow is away from buildings

• Berm higher near building

• Overflow sheets over lawn or garden

• Overflow sheets over driveway or walkway

• Flows onto street - an existing storm drain can be used as an outlet for a rain garden Stormwater 101 Install the Overflow Stormwater 101 Planting Summary Stormwater 101 Determine Mulch Quantity

• Triple-shredded hardwood mulch with no dye is used in a rain garden • Mulch should be maintained at a 3 inch depth (100 square feet of garden = 1.0 cubic yard of mulch).

• The benefits of mulch:

• Keeps soil moist, which allows for percolation of rain water

• Protects plants and makes weeding easier

• Minimizes erosion of the rain garden soil Stormwater 101 Installation Steps Water the Vegetation

Hockman Farm, Winchester, Virginia Stormwater 101 Designing With Native Plants

http://plants.usda.gov Types of Plants Facultative Upland (FACU), Upland (UPL) Obligate Wetland (OBL), Facultative Wetland (FACW)

Highest Zone/ Lowest Zone/ Ponding Area Upland Area

Middle Zone/ Depression Area Facultative Wetland (FACW), Facultative (FAC), Facultative Upland (FACU) Stormwater 101 Rain Garden Design

SHAPING YOUR RAIN GARDEN • Use a garden hose or rope to outline the desired shape of your rain garden on the ground • Many rain gardens are in the shape of a circle or kidney bean, but your rain garden can take on whatever shape you prefer Stormwater 101 Selecting Native Plant Species

• Mature plant size – Proximity to buildings and utility lines – Pruning and shaping

• Seasonal interest – Flowers – Fall color – Winter character

• Beneficial wildlife – Flowers for butterflies – Fruits for song birds Butterfly Weed – Purple Cone Flower – UPL UPL Asclepias Echinacea purpurea Dense Blazing Star – FAC+ tuberosa

Black-eyed Susan – FACU Wild Bergamot/ Bee Balm –UPL Beach plum – UPL Rudbeckia hirta Mondarda punctata Prunus maritima Virginia rose – UPL Rosa virginiana Lowbush blue berry – FACU- Soft rush – FACW+ Vaccinium angustifolium Juncus effusus

Fragrant sumac - UPL Blue flag iris – Maple leaf viburnum – UPL Rhus aromatica OBL+ Viburnnum acerifolium Iris versicolor Sweet pepperbush – FAC+ Clethra alnifolia Meadowsweet – FAC+ Spiraea latifolia Cardinal Flower – FACW+ Lobelia cardinalis

Boneset – FACW+ Purple Joe-pye – FAC Spotted horsemint – UPL Eupatorium perfoliatum Eupatorium Monarda punctata purpureum Stormwater 101 PARTS OF THE RAIN GARDEN Stormwater 101 GRASSES & GROUND COVERS

PONDING SLOPE BUFFER /BERM AREA

• Bluejoint grass • Big bluestem • Broomsedge • Sedges • Virginia wild-rye • Bearberry • Fowl mannagrass • Switchgrass • Panic grass • Softrush • Wool grass • Switchgrass • Little bluestem • Indiangrass Stormwater 101 WILDFLOWERS & FERNS

PONDING AREA SLOPE BUFFER /BERM • Swamp milkweed • New England aster • Butterfly milkweed • Marsh marigold • New York aster • Wild indigo • Turtlehead • Columbine • Purple coneflower • Boneset • Coreopsis • Beebalm • Rose- • Joe-pye • Black-eyed susan mallow/hibiscus • Blazing star • Blueflag iris • Sensitive fern • Cardinal flower • Cinnamon fern • Blue lobelia • Ironweed • Royal fern TREES & SHRUBSStormwater 101

PONDING AREA SLOPE BUFFER /BERM

• River Birch • Red Maple • Hackberry • Buttonbush • Service Berry • Red Bud • Silky Dogwood • River Birch • American Holly • Green Ash • Silky Dogwood • Bayberry • Red-twig Dogwood • Swamp White Oak • Witchhazel • Green Ash • Pin Oak • White Oak • Winterberry • Cranberrybush • Red Oak • Sweetbay • Arrowwood Viburnum Viburnum Magnolia • Pepperbush • Low Bush Blueberry Stormwater 101 A Rain Garden Over Time Stormwater 101 Stormwater 101

• Rain gardens are designed to intercept, treat, and infiltrate stormwater at the source, before it becomes runoff. • The plants are native to the region and help retain contaminants that could otherwise harm nearby waterways. • Rain gardens are beautiful, inexpensive and low- maintenance gardens that you can easily install at home. Linda Henry Linda Henry

Woodbridge Board of Health, Middlesex County