RAIN GARDEN HISTORY: RAIN GARDENS: HOW DID RAIN GARDENS STORMWATER SOLUTIONS Stormwater GET STARTED? FOR ANY LOCATION Best Management Practices

Mother Nature created our first rain gardens. Before humans changed the URBAN: Nonpoint Source Pollution landscape, rain was filtered through soils, Rain gardens can be Reduction Strategy: roots and plants in our native forests, installed in wetlands and meadows. The majority of parking islands RAIN GARDENS the water that entered our streams was instead of the cool, clean groundwater. traditional raised grass As we built homes, roads and island, which infrastructure, the natural water-cleaning requires systems were gradually removed. Our mowing. streams and rivers became increasingly degraded as water ran off the land instead RESIDENTIAL: of being taken up by plants, soaking into the soil, and being filtered by soils and wetlands. Rain gardens, or bioretention areas, were first conceived in 1990 by Before stormwater specialists in Maryland. The goal was to design a practice to mimic naturally occurring functions that help filter rain water.

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Montgomery County Financial support for this project is provided by the Conservation District Pennsylvania Department of Environmental Protection though Growing Greener and Environmental Education 143 Level Road, Collegeville, PA 19426 Funds and the Pennsylvania Association of Conservation Phone: 610-489-4507 District’s Mini-Grant. montgomeryconservation.org STORMWATER RUNOFF RAIN GARDENS QUALITIES & BENEFITS POLLUTION Rain Gardens are bioretention areas, slightly OF RAIN GARDENS graded to retain water, and filled with native Stormwater runoff pollution occurs when plants. These areas attempt to reproduce the Environmental Benefits: precipitation flows over lawns, parking physical, chemical and biological processes of  Installing a rain garden makes you lots, farm fields, city streets and other the natural environment to create a more part of stormwater pollution solution impervious surfaces, picking up pollutants efficient, on site, water treatment area. The by absorbing and filtering rain that and carrying them into our streams, incorporation of plants, mulch and soil would otherwise run off your rivers and oceans. introduces natural biological processes that property and down the storm drain. provide two important functions: (i) water  Rain gardens are lovely landscaping Activities like littering, lawn over- quantity (flood) controls; and (ii) water quality features and create wildlife habitat. fertilization, and improper disposal of improvements through removal of pollutants  Rain gardens help recharge our chemicals contribute to the and nutrients associated with runoff. groundwater resources. contamination of our local waters. These Rain Gardens gather and store runoff Maintenance: activities gradually increase the level of rainwater until it can evaporate, be used by  Rain gardens are low maintenance. pollution in our waterways. plants, or soak into the soils. This infiltration is  Rain gardens can save you money by important to recharge groundwater for human reducing the amount of lawn you What can each of us do? consumption and for maintaining stream base have to maintain. flows. Strategies for preventing pollution of our Rain Gardens resemble a typical perennial waterways focus on reducing the amount Application: garden in many ways. The garden bed is of runoff that can wash pollutants off the  A typical grassed lawn can be easily prepared, or sometimes replaced, to a depth land, and reducing the amount of retrofitted with a beautifully of several feet in order to de-compact the pollutants that can be washed into landscaped rain garden. soils, making the garden able to absorb water. streams. Reducing impervious surfaces,  Rain gardens can be any size and Designed with deep-rooted flowers, grasses, planting native species with deep roots, placed in a variety of areas where rain trees and shrubs, a well designed rain garden is and installing rain gardens and rain barrels water runoff can enter the garden. low maintenance and looks great. are great ways for homeowners to Take Note: manage stormwater, reducing the amount Cross-sections of engineered rain gardens:  Rain gardens have a ponding area, of runoff from their properties. Pipe Connected to Roof Drains Domed Riser for Overflow but they are not ponds. There is a Plants - ideally native bowl-shaped dip in the garden, which It is equally important that each of us holds the rain while it soaks into the contribute as few pollutants as possible Soil / Planting Mix soil, but this should not last for more to the watershed. Pick up after pets, Sand Bed than a day or two after a rain event. wash your car at a car wash, use (opt) Gravel Base (opt)  Rain gardens are often planted with sustainable products, do not litter, wetland plants, but they are not prevent soil erosion, and dispose of yard Water flowing off impervious surfaces Native plants or hardy cultivars wetlands. waste, hazardous chemicals, and (i.e. roofs or driveways) Ponding depth: 6-12” can be delivered to the Mulch layer  Many of the plants in the garden are pharmaceuticals properly. There are a rain garden through a Rain Garden soil mix pipe, swale, or Gradual side slopes native to the region and have host of other everyday behaviors to landscape area. Overflow extensive deep roots that help the prevent pollution; just keep waterways in garden absorb rain. Existing ground Rain Garden soil mind! mix depth (12-24”)