Overview Background & Basics Design Constraints Plant Species Design Process Rain Garden Overview Cost Analysis Maintenance Issues Summary

What is a Rain Garden? A planted depression that allows rainwater runoff to be absorbed Intended to prevent flooding and filter the runoff Makes an otherwise dreary spot more aesthetically pleasing

Functions Diverts runoff from impervious paved surfaces or roofs Helps to remove pollutants Replenishes groundwater

How does it work? Water enters rain garden through spout or drain system Ponding occurs in rain garden lasting 1 to 2 days Water seeps into the soil over time using the vegetation as natural filtration

Benefits Absorbs up to 30% more rainwater runoff than grass Helps clean runoff of pollutants Prevents flooding Provides a habitat for wildlife, such as butterflies and birds

Rain Garden Location Linden Hall provides optimum location for rain garden Easily accessible runoff from roof Relatively low traffic area Help to increase aesthetics in area Alcove allows for more controlled environment

Design Constraints For safety reasons, the volume of the garden should not be able to conceal a person Along adjacent sidewalk expect crushing snow so use plants that are able to bounce back in the spring Lawn mower operators must be able to mow the remaining lawn with a 72 inch lawn mower without ever backing up Plants have to be chosen from a predetermined list

Rain Garden Vegetation Six plant types suitable for rain garden Swamp Azelea (Rhododendron viscosum) Disco Belle Hibiscus (Hibiscus moscheutos) Cardinalis Flower (Lobelia cardinalis) Ruby Spice Summer Sweet (Clethra alnifolia) Sweetfern (Comptonia peregrina) Little Henry Sweet Spire (Itea virginica) Chosen for their hardiness and aesthetic aspects

Rain Garden Vegetation Swamp Azelea (Rhododendron viscosum) Mature height: 2 – 8 ft Prefers saturated soils Highly visible white flowers Disco Belle Hibiscus (Hibiscus moscheutos) Mature height: 6.6 ft Shrub-like herbaceous perennial White or pink flowers with crimson centers

Rain Garden Vegetation Ruby Spice Summer Sweet (Clethra alnifolia) Mature height: 5 – 8 ft Long flowering and growing period Yellow fragrant foliage Cardinalis Flower (Lobelia cardinalis) Mature height: 2 -3 ft Shade tolerant Cardinal red flowers

Rain Garden Vegetation Sweetfern (Comptonia peregrina) Mature height: 2 ft Good in coarse and medium textured soils Green leaf blades Little Henry Sweet Spire (Itea virginica) Mature height: 3 – 5 ft Native to NJ soils Yellow spiral leaves

Rain Garden Design Rain gardens are design using several parameters Amount of Precipitation Imperviousness of Runoff area Average depth of water in rain garden First, need to determine runoff depth Curve Number (CN) is 98.

Rain Garden Design Next, determine Runoff area for rain garden Roughly 1500 ft2 Area x Runoff Depth = Runoff Volume Runoff volume is the amount of water the rain garden can hold Finally, get needed surface area of rain garden Runoff Area

Rain Garden Design The assumptions made for design: Precipitation = 1 inch Asphaltic Roof Average depth of rain garden = 4 inches Final Design Results Runoff Area = 1500 ft2 Runoff Volume = 104.42 ft3 Rain Garden Surface Area = 313 ft2

Design for Linden Hall Oval shaped Will have sloping sides Average depth is 4 inches Accessible for maintenance

A Closer Look Little Henry Sweetspire Swamp Azalea Ruby Spice Summer Sweet Disco Belle Hibiscus Cardinalis Flower Sweetfern

Cost Analysis Labor being done by various student organizations Mulch & Vegetation pricing based on rough estimates Miscellaneous Expenses covers construction materials (i.e. piping, liners) Pricing Information Construction Element Unit Cost ($/sq.ft.) Total Cost ($) Vegetation 3.00 950.00 Mulch 0.30 95.00 Misc. Expenses 1.00 317.00 Total 1362.00 Although, this may seem expensive some of this cost can be mitigated with the help of available resources (i.e. facilities, grants, etc.)

Maintenance Pull weeds, especially during the 1st year Water 3 times a week until established, and also during dry spells Re-mulch (shredded hardwood won’t float away) Cut back and trim as needed

What about mosquitoes? Mosquitoes need at least 7 days in standing water to hatch A rain garden is not a pond, and will usually dry out within a day or two

Summary Rain gardens help to reduce pollution and divert runoff Linden Hall is an optimum location for a rain garden Majority of design and plant selection is finished Require little maintenance Overall, a rain garden is a low-cost, aesthetically pleasing option for any university

Thank you for your time. Any questions?