Rain Garden Build Thread
 

I'm making one this summer. I know they're popular in Kansas City, because they have been publicly pushing them for a few years now.
This post explains the background for my decision, local issues, and logic of why you should make a rain garden.

Here's some background:
I live in St. Louis City, in a small house on a small lot. All the houses in the city have gutters that dump straight into the sewer. 100 years ago when most of these homes were built, no one cared about putting human and household waste into the rivers. Now it's known to be a problem, but it's not feasible to put in separate pipes for storm and sewer drains to each property. All of our sewers drain to the same place, even the ones off the streets - to the wastewater treatment facility, then to the Mississippi River. Normally fine, but every time we have rain that's more than a sprinkle, the sewers are overstressed. To avoid backups into hundreds of thousands of basements, our utility has hundreds of overflow points where wastewater dumps straight into local creeks and streams untreated. (A BIG problem)

I'm trying to make our property output as little stormwater as possible; we already send very little wastewater out of our home.
I made a rain barrel last year and it worked great. I have two gutters; each drains 1/2 of our home. I can't put a barrel on the front gutter; the wife won't allow it. (she wasn't fond of the one on the back at first)

It's time to eliminate what I can of the front gutter's input into the sewer, and I'm going to make a rain garden. Basically a rain garden is a detention pond with plants in it. The garden fills with water when it rains, submerging some of the (tolerant) plants for up to 4 hours. The water from the garden soaks into the ground, feeding our aquifer, instead of running off and causing stormwater/wastewater issues.

Many people have "rain gardens" that either don't do much or create more runoff; I support their efforts, but I want to lead with a good example; my city is just coming around to advocating rain gardens.

Schematic to follow...

http://img61.imageshack.us/img61/7531/raingarden.png
The detention bucket is a small (maybe 2 gallon?) bucket with a screen at the top. It helps control the water and get it to one of two places: Into the rain garden, or under a super-downfall or in the event of a blockage, into the sewer as normal. It is filled with concrete to keep it from blowing around, and connects to a PVC pipe that is buried under my front yard (not to scale - it's 20+ feet to the sidewalk) and that pipe empties onto the sidewalk. Water flows across the sidewalk and into the rain garden, and if it manages to overflow into the street, dense groundcover will prevent too much erosion.
Whatcha think?

I think thats a great idea. My wife went to school for environmental planning and I can remember her talking about how redirecting rain water and other things that effect rain water cause so many problems. Just think of the problems that would be solved if every other person did this in your city. The results would probably save millions of dollars not just for the treatment costs, but also in healthcare and building (in the form of rebuilding) costs.

I don't understand why the gutters are connected to the sewer at all. Just dump the excess water from your rain barrel onto the lawn.

My roof has the same surface area of my whole yard, including impermeable concrete. OK to do in the suburbs or country, but here that would mean running off right into the street, and ultimately, the sewer.