The Gills Creek Watershed contains over 70 miles of streams and lakes, and 47,000 acres of land. It was majorly impacted by the 1,000 year flood in October 2015. Plans are underway to improve water quality, and add trails along certain sections. This Earthcache will teach you a little bit about cleaning rain water before it reaches our streams and rivers.

What Is A Rain Garden?

A rain garden uses design and plant selection to help clean storm water run off from shopping centers and roads. It is usually a small garden which is designed to withstand the extremes of moisture and concentrations of nutrients like nitrogen and phosphorus that are found in storm water runoff. Rain gardens are sited ideally close to the source of the runoff and serve to slow the storm water as it travels downhill, giving the storm water more time to infiltrate and less opportunity to gain momentum and erosive power. 

Below the surface of the garden, a number of processes are occurring which mimic the hydrologic action of a healthy forest. Storm water is cleaned and reduced in volume once it enters the rain garden. Nitrogen and phosphorus levels and overall sediment loads in the storm water are reduced by the action of the plants and growing media on the water.  Multiple rain gardens over an area will have a positive cumulative effect on both the volume and quality of storm water run off.

Rain gardens are designed to be drained within four hours after a 1” rain event. Under-drained rain gardens typically are designed to drain within 2 hours of the design storm event. This is achieved through the use of highly porous planting media and underdrains which carry the cleaned rainwater away from the garden. As a result, the plants selected for the bioretention cell need to be able to withstand both the extremes of flooding and drought.

Logging Requirements:

1) According to the diagram on the informational sign what are the 5 steps of the rain garden filtering process.

2) How many rain gardens are located in this complex? Is this the biggest one?

3) According to the map of the watershed map, how many lakes are formed from this creek?

4) What state park does Gills Creek flow through?

5) Estimate the diameter of the rain garden in front of you.