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Overview Background & Basics Design Constraints Plant Species

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Presentation on theme: "Overview Background & Basics Design Constraints Plant Species"— Presentation transcript:

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

2 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

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

4 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

5 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

6 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

7 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

8 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

9 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

10 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

11 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

12 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.

13 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

14 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 = ft3 Rain Garden Surface Area = 313 ft2

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

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

17 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 Although, this may seem expensive some of this cost can be mitigated with the help of available resources (i.e. facilities, grants, etc.)

18 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

19 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

20 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

21 Thank you for your time. Any questions?

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