What is a Rain Garden? EarthCache
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As with any earthcache, there is no “container” to find. Rather, you discover something about the geology of the area. For more information please consult www.earthcache.org
The posted coordinates will take you a rain garden and informational sign in Lower Allen Township Park. Please, only visit during daylight hours when the park gate is open!
What Is A Rain Garden?
When rain falls on natural areas such as a forest or meadow, it is slowed down, filtered by soil and plants, and allowed to soak back into the ground to recharge groundwater resources. When rain falls on impervious surfaces such as rooftops, roads, parking lots and driveways, rain does not soak into the ground and storm water runoff is created. Stormwater runoff picks up pollution such as fertilizer, pesticides, sediment, motor oil, litter, pet and yard waste. In many areas, stormwater runoff does not go to a treatment plant. Instead, water and the pollution in it flows directly into storm drains, which eventually can deliver these pollutants to bodies of water.
Rain gardens are attractive, functional landscaped areas designed to capture and filter stormwater before it runs off into storm drains. They collect water in natural or constructed shallow vegetated depressions and allow it to soak into the ground slowly. This reduces the potential for erosion and minimizes the amount of pollutants flowing from a yard into a storm drain, and ultimately into our waterways. They may also be used as a buffer in shoreline areas to capture runoff from the home landscape before it enters a lake, pond, river or estuary. Rain gardens use the concept of bioretention, a water quality practice in which plants and soils filter pollutants from stormwater.
By reducing stormwater runoff, rain gardens can be a valuable tool to help protect our water resources. While an individual rain garden may seem like a small thing, collectively they produce substantial neighborhood and community environmental benefits. By capturing runoff in shallow depressions and letting it soak into the ground, rainwater gardens also help recharge stores of groundwater in aquifers. Moreover, they filter out sediment and other pollutants by catching close to the first inch of runoff, which contains the highest concentration of pollutants. Rain gardens transform stormwater from a destructive carrier of pollution into a source of sustenance for plant and wildlife habitats: the plants thrive on nitrogen and phosphorus that is picked up, while their stems trap sediment. Rainwater gardens are being incorporated into many new and existing areas for their environmental benefits, as well as their natural beauty.
A rain garden resembles a regular perennial garden or mixed border in many ways. It is designed with deep-rooted plants that come back year after year; it is pretty to look at; it often has lovely flowers, grasses, trees and shrubs. So what makes it different from any other perennial garden? There are certain qualities that make a rain garden unique:
• Rain gardens have a ponding area, but they are not ponds. They often are planted with wetland plants, but they are not wetlands (although you can design a rain garden that mimics a wetland).
• The garden absorbs and filters rain that would otherwise run off your property and down the storm drain.
• Many of the plants in the garden might be native to the region and have extensive deep roots that help the garden absorb rain. The native plants do not need special attention once they are established. Non-native plants may be used as long as they are also non-invasive and pest free.
• There is a bowl-shaped dip in the garden, which holds the rain while it soaks into the soil.
• The garden bed is prepared or sometimes replaced to a depth of up to two feet in order to relieve soil compaction and make the garden able to absorb water.
A garden that does not have rain directed into it from a hard surface will still be a valuable asset. However, unless stormwater runoff is directed into the garden, it is not a rain garden. In addition to reducing and filtering stormwater runoff and increasing groundwater recharge, rain gardens provide many other benefits. They provide habitat for wildlife and, with the proper selection of plants, increase the number and diversity of birds and butterflies for those who enjoy watching them.
Logging Requirements: Send the answers to the following questions through our profile page. DO NOT post the answers in your logs!!
1. Using the nearby WHAT IS A RAIN GARDEN signage please tell what three of the five listed benefits of rain gardens are?
2. On the sign there is a depiction of an overhead view of a home rain garden taken from www.rainscaping.org. What is the size (either dimensions or area) of the rain garden example?
3. In the sign's graphic from www.urbanworkbench.com, what three materials should you use for the BOTTOM layer in sheet mulching?
4. What is the general shape of the particular rain garden here? If it isn't square or rectangular, pretend it is, and estimate its area in square feet (LxW)?
5. Based on the information presented above and what you see here, is this rain garden meeting the criteria of a rain garden in this location? Do you believe it is successful?
6. Using your knowledge of the area, your GPS, a map, or other tool, please state what nearest natural body of water is benefiting from the rain garden's filtration benefits. Bonus if you know enough about the watershed to indicate the end downstream beneficiary (hint: it is not in Pennsylvania)!
7. (OPTIONAL) Post a picture of yourself and/or your GPS with your log that shows you and/or your GPS at the cords with the rain graden in the background. Please DO NOT include pictures of the sign in the background!
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