Every time it rains, a bit more of the soil around my house erodes away. We don’t have any gutters currently and most of the lot slopes down a bit towards the creek. Naturally, I was more than happy to attend a free Green Stormwater Conservation class this weekend to get some ideas on what to do about it.
Before sharing some of what I learned though, I wanted to share a few pics of the beautiful artwork at the Zaragosa Recreation Center. The artwork was all over the classrooms, too. An awesome tribute to our latino background.
The class itself was led by Staryn Wagner of the Austin Watershed Protection Department. For three hours, he showed us pictures of streams that had been eroded, told us stories of various chemicals and other nasties that get into the water in different parts of Austins, and taught us all about what we could do to prevent excessive flow of water into the streams whenever there’s a storm event with all the impermeable surfaces around. There’s probably no one who loves rain gardens more than Staryn.
One of the things that I was surprised to learn was just how beneficial ragweed is for streams. The creek by my house is covered with the stuff, and whenever I looked up ragweed online the results were full of much cursing and disdain for the plant. However, it turns out that in addition to the soil improvements that most weeds provide, ragweed is also great for storm management (although there are more aesthetic options if you have the money and time). As soon as the storm water comes, the ragweed bends over so the rush of water can flow over top while protecting the precious soil underneath. I’m thrilled that this means there’s one less thing I need to take care of, and it’s fine to leave the ragweed in place for now.
For landscape design, there’s vegetation, swales, and berms. However, as might be guessed from above, Staryn’s favorite feature to talk about is the rain garden. There are many types of these, but it pretty much amounts to having a depression in the ground designed to hold and slowly absorb water. They’re any shape and size but are generally from 4 to 12 inches deep so they can hold plenty of water but not take more than a couple of days to drain (to prevent mosquito problems). In addition to the info linked above, there are some more examples on the CreekSide Story blog.
And finally, the part I’d been waiting for–rain catchment systems. Since my roof needs to be replaced soon and I have erosion issues, looking into gutters and rain tanks has been on my list since moving in. I had been thinking of a smaller system, but Staryn said he wanted every home to have a 1,000- to 3,000-gallon system. Yipes! Of course, his perspective wasn’t so much about having the water for use in the landscape but to protect the watershed during storm events. Since I don’t plan on dealing with rain harvesting installation more than once, it’s time to crunch some numbers and see if a larger system actually makes sense for us before getting into the process.
I’d never heard this mentioned before, but as shown above, it’s recommended to have the rain tank surrounded by a rain garden to both filter the first flush water and help handle anything in excess of capacity. That’s something I can totally do on my own, though.
There are three features to keep leaves and gunk from your roof from getting into your water tank.
- Gutter screens – to keep leaves from entering your gutters. The smaller the filter, the more that will be kept out. The weaker your screens, the more likely stuff will just weight it down and clog the gutters.
- Downspout filter – to catch any leaves that get through when part of the gutter screen inevitably tears.
- First flush system – to capture the dirtiest roof-scrubbing water at the start of the storm and direct it away from the main tank. (Pro tips: Have a drainage hole at the bottom of your first flush system and one a little higher up to ensure it will empty on its own. Also, make it easy to remove the first flush system for cleaning.)
Another pro tip is to have multiple spouts for your tank. After the presentation, Staryn showed us the rain tank he installed at the Zaragosa Recreation Center. This (what looks to me huge) 1250-gallon tank only collects water from just one portion of their roof. This is an interesting system because the first valve will only empty until the tank is half empty. Another valve will empty to a lower level. And the final valve will release any water. Actually, there’s one more valve right near the tank so the flow can be disabled if the other valves need to be maintained or modified.
I didn’t get any pictures of the surrounding area, but there’s a nice little rain garden around this tank with native plants. And across a little walkway, there’s a low area which was then filled up on the down-sloping sides in order to hold water. So whenever there’s a large flow of water, that’ll act as a rain garden to capture it and allow it to seep back into the ground.
With that in mind, here’s a picture of my own already created rain garden after some of our spring rains. You may not be able to tell because the grass is a bit high, but that’s a pretty huge puddle next to the house. I’m already doing a bit for diverting water from flooding the creek too quickly and allowing more to soak in. Before this class, I was planning on filling it in with some dirt, but now I’m proud of it.
Seriously, though, I’m definitely going to add some dedicated rain features into my yard over time. I’m good with a shovel. 🙂