Rain Garden Planning

What kind of hippy mom would I be if I didn't have at least one rain garden? What is a rain garden? A rain garden is a sunken garden bed designed to catch storm water and filter water back into the ground naturally. Rain gardens have many benefits. They are a simple way to protect our streams and rivers, provide food and habitat for birds and butterflies, and best of all, are planted with hardy low-maintenance plants.

 I have been taking rain garden workshops from East Multnomah Soil & Water Conservation District, so I like to think I sort of know what I am doing. My yard is more or less a blank canvas of weeds and crab grass. Sounds terrible? Not at all! This is an opportunity to let my imagination run wild. My first project will be a couple of rain barrels plumbed into rain gardens. There is actually a lot of planning that goes into engineering a rain garden. First, I drew a layout of my house and property and calculated the area (sq/ft) of roof draining into each down spout. Then, I took 10% of the total area and that is how many square feet my rain garden will have to be.

After drawing everything out we dug a one foot by one foot hole and filled it with water a couple of times and timed how fast the water drained out. If it drains out too slowly or not at all then a rain garden is not for you. To our luck the soil was fabulous draining at about an 6 inches an hour in the back yard and  12 inches an hour in the front yard. That is fast draining soil! However, in an actual Pacific Northwest rain event complete soil saturation will likely cause a slower drainage rate.

My goal is to have the gardens finished by the end of February. I will post the progress over the next couple of months. The next step is to draw out the individual beds and select the plants.