The document discusses the benefits and design considerations for building raingardens. Raingardens are shallow depressions planted with vegetation that improve stormwater quality through biological and soil processes. They reduce runoff, recharge groundwater, and remove various pollutants. Key factors in designing raingardens include the watershed size, soil type, utility locations, plant selection, and ensuring proper overflow drainage. Several examples of existing raingardens are also presented.

2. Building Raingardens Presented to: Massachusetts Association of Landscape Professionals November 12, 2008

7. Raingardens: The simple definition. A shallow depressed planting bed designed to improve the quality of stormwater runoff through biological process of plant and soil interaction, and by infiltrating stormwater back into the ground.

20. Soils and Geology 3 days after 2” rain This water should have infiltrated. Rain garden constructed on very dense clay soils i.e. Glacial till or “hardpan”

22. Bioretention Cell - Raingarden

23. Site Location

24. Excavation

25. Excavation

26. Final Subgrade

27. Material Stockpiles

28. Coarse Sand

29. Topsoil/Compost Mix

30. Hardwood Chips

31. Soil Mixing

32. Crushed and Pea Stone

33. Underdrain Construction

34. Placement of Bioretention Soil Mix Demonstration Raingarden at Lily Pond

35. Planting June 2005 Demonstration Raingarden at Lily Pond

36. First Rain Storm Demonstration Raingarden at Lily Pond

37. September 2005 Demonstration Raingarden at Lily Pond

39. Other Examples Dennis, MA Silver Lake, Wilmington, MA King St, Cohasset, MA Manchester, NH Norfolk MA Leominster, MA

40. Other Examples

41. Lost Opportunity

42. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron LLC Landscape Architecture, Scituate, MA Plant Selection Criteria Aesthetic Considerations: Neighborhood style – architecture and landscapes. Front yard visibility. Color .

43. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron, LLC Landscape Architecture, Scituate, MA Plant Selection Criteria Environmental Considerations: Variable Soil Moisture : Long periods of drought. Short periods of inundation. Variable Exposure to Light : Full sun. Deep shade. Cold hardiness . Harsh Road Edge Conditions : Snow plowing and snow stockpiling. Salt tolerance. Native Plants . Biodiversity .

44. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron LLC Landscape Architecture, Scituate, MA Prototypes White Rain Garden Compact Cranberrybush Viburnum trilobum 'Compactum' American Elder Sambucus canadensis White Gayfeather Liatris spicata 'Floristan White' Henry's Garnet Virginia Sweetspire Itea virginica 'Henry's Garnet' Winterberry Ilex verticillata 'Winterred' Dense Inkberry Ilex glabra 'Densa' Annabelle Hydrangea Hydrangea arborescens 'Annabelle' Slender Deutzia Deutzia gracilis Variegated Red Twig Dogwood Cornus sericea 'Elegantissima' Redtwig Dogwood Cornus sericea Compact Summersweet Clethra alnifolia 'Hummingbird' Summersweet Clethra alnifolia

45. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron LLC Landscape Architecture, Scituate, MA Prototypes Pink Rain Garden Pinkshell Azalea Rhododendron vaseyii Swamp Azalea Rhododendron viscosum Purple Gayfeather Liatris spicata 'Floristan Violet' Kobold Gayfeather Liatris spicata 'Kobold' Dense Inkberry Ilex glabra 'Densa' Strawberry Fields Deutzia Deutzia sp. 'Strawberry Fields' Variegated Red Twig Dogwood Cornus sericea 'Elegantissima' Redtwig Dogwood Cornus sericea Pink Summersweet Clethra alnifolia 'Ruby Spice' American Beautyberry Callicarpa americana

46. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron LLC Landscape Architecture, Scituate, MA Prototypes Green & White Rain Garden Snowhill Sage Salvia sylvestris 'Snowhill' Dw.Purpleosier Willow Salix purpurea 'Nana' Grow Low Fragrant Sumac Rhus aromatica 'Gro Low' White Gayfeather Liatris spicata 'Floristan White' Annabelle Hydrangea Hydrangea arborescens 'Annabelle' White Coneflower Echinacea purpurea 'White Swan' Compact Nikko Deutzia Deutzia gracilis 'Nikko' Compact Kelsey Dogwood Cornus sericea 'Kelseyi'

47. Cohasset BMP Implementation Project Rain Garden Prototypes Coyle & Caron LLC Landscape Architecture, Scituate, MA Prototypes Lily Rain Garden Kobold Gayfeather Liatris spicata 'Kobold' Purple Gayfeather Liatris spicata 'Floristan Violet' W. Amethyst Medallion Daylily Hemerocallis sp. 'Woodside Amethyst' Stella de'Oro Daylily Hemerocallis 'Stella de Oro' Rosy Returns Dw. Daylily Hemerocallis 'Rosy Returns' Indian Giver Medallion Daylily Hemerocallis sp. 'Indian Giver' Sweet Fern Comptonia peregrina Moonshine Yarrow Achillea sp. 'Moonshine'

48. Maintenance