Building a Raingarden for Tulsa Partners

As part of the kickoff of Tulsa Partner's Green Building Resource Library on September 24th, we will be installing a raingarden at the TPi office! There's a good bit of prep work that goes into building a raingarden, so I thought I would use the blog as repository of everything we can't get into the short on-site workshop we'll conduct that evening.

I went by today and took few photos of the office. The downspouts are already disconnected, so that is one thing we won't have to do. There is one downspout on the southeast corner of the building that discharges to a sunny, grassy spot. Its visible from the street and building entrance, which is great from an educational perspective. Its also in a nice sunny spot, which gives us a good range of plants to work with.  See the downspout on the right side of the roof overhang.

I then walked off the area of the roof handled by this downspout.  Its about 20' across and 25' long, or 500 sf.  I'll do a field check of infiltration later, but just as a starting point we could assume 6" of infiltration/24 hours, resulting in a 6" deep garden. For a garden that would handle the first 1" of runoff, that would require 500/6 = 83 sf of garden.  The space available is 80sf, max.  So, let's say we get more infiltration, say 8"/24hours.  That would make our garden 500/8 = 62.5 sf.  Probably more likely to fit the space, but we'll check the infiltration to be sure the soil can handle it.

What if we don't have the infiltration needed for this size roof?  Just size the garden depth for the infiltration (depth = infiltration in 24 hours but 12" maximum).  A smaller garden than your runoff volume requires just means you'll be capturing less than the first 1", and the first 0.5" is typically the most important, so that gives you a good range for the available space.

Here's another look at our site.

Ready for a Green Roof? Try This!

Ok, this is a DIY project for LIDers who want to try out a green roof, but may not be ready or able to tackle something full-scale.  How about a green doghouse, or shed?  This is a no-power-tools-required project that can be done over a weekend, or with a few hours here and there. 

Step 1:  Cover the roof that came on the structure with roofing felt cut to size with a utility knife.  Attach it using gavanized roofing nails.

 

Step 2: Creat two frames to hold potting soil mix (regular soil is too heavy) by attaching cedar or treated 1x4s to the front , sides and ridge of the roof using galvanized nails.  Add a 1x4 board across the middle of each side, horizontally, to help reduce soil erosion when it rains. 

Step 3:  Fill in the frames created in Step 2 with a thin layer of gravel overlain by potting soil.  Cut chicken wire with wire clippers to cover the frames, staple chiken wire to the wood to hold the soil in place.  (At our house, the dog recently destroyed a bean bag chair, so we amended the soil with those tiny beads to improve its drainage and weight!)

Step 4:  Plant succulents or low growing plants that are adapted to the climate in your area.  Look around your garden - what already grows and spreads without being watered?  Use it!  Shake excess soil from the roots, snip a hole in the chicken wire, and carefully (the wire is sharp!) tuck the roots in.  Finish by filling the spaces between plants with sheet moss.  The plants will quickly cover the moss and hang over the edges.

Step 5:  Water about twice a week intially, until plants are establisted.  Feed during growing season with 20-20-20 water soluble fertiler to keep it looking its best.

Depending on how well the structure is supported, you could try this on a playhouse, shed, chicken coop or detached garage.  Larger structures will likely need additional support.  Have fun and get green with this great LID project.

This project was edited from Southern Living's June 2010 edition, by Joyce Butterworth.

What's the Difference?

These photos are not intended to pick on Home Depot but are representative of most big box development. Question: What's the difference in these two photos?   The top photo is typical of what we see most commonly in Oklahoma commercial development - big box, big parking lot, big runoff.  But what of the second photo - same company but a very different approach.   Is it geography? Is it rainfall?  A unforeseeable landscaper strike?  The answer is actually none of the above, but rather Policy.  The second photo represents development in a community that asks more, and recieves what they ask for. And not that they ask, but they require, through codification, that their community be cared for in specific ways.  I was watching "Cars" with my kids and found motivation from the local lawyer asking "Are we worth having this done right? Is our town worth it?" when the residents were satisfied with status quo. 

I would like to ask our councilors, our mayor, our public works officials: Is our town worth it?  Is our river worth it?  Asking for funding for river development is somewhat futile if we won't also take enough pride in our community to say - do more than the minimum.  The difference is not what you see, its what you don't see:  the policies and codes that say our community is worth the effort.

What are the most common LID practices in Tulsa?

I had someone ask me this question recently and it made me run around town to take some more pictures. LID that has been designed intentially to improve stormwater quality or affect stormwater quantity is not easy to find. What is more common are aesthetic landscaping features that accomplish this task. One example is canopy cover. Tulsa has long reaching goals for canopy cover and recovery/replacement of trees lost in 2007's ice storm. A great side effect is that canopy cover, when trees are in leaf, significantly reduces stormwater runoff. The effect is huge compared to areas of pavement. Some common examples are trees planted in medians, which only achieve the desired effect when they overhang roadways and sidewalks. Here are some local examples:But there are places that go above and beyond when placing trees. One of my favorites is the area surrounding One and Two Warren Place, at 61st and Yale. The roadway to the right is one example. They have included a mix of deciduous trees (median, right of photo) which affect stormwater runoff during parts of the year, and also evergreens, which achieve the same effect year round. And if you have the chance to visit, take a look behind One Warren Place (1st photo above) and see the surface parking. The plantings could make you forget you were in an urban setting, and are a far cry from the standard surface parking you would see downtown, or anywhere else for that matter.

Heifer International - Wetlands

We're back to Heifer International in Little Rock - there was so much to write about! Besides rainwater use on-site, rainwater is also collected and treated through a variety of LID systems. One are the wetlands shown in the previous post. In practice, rainwater falls on the roof, which has been finished as something closer to a swimming pool than your typical roof.

Rainwater is channeled into downspouts, which have been designed as a functional architectural feature. The kids thought these would be great slides during the rain!

The downspouts become horizontal channels closer to the ground. Rainwater flows over the side of the channel, which function like a weir, into the stabilized forebay of a raingarden. You can see the channel as well as reeds in the raingarden to the right.

A surface drain at the end of the raingarden allows stormwater to flow into the wetlands at the site. The wetlands surround the main office building, giving it a castle and moat feeling. But most of all it's lovely, with ducks, turtles and fish enjoying this site, which was previously a contaminated industrial facility.

Below is a design schematic for the wetlands, similar to many, many we've seen in LID and stormwater guidance manuals. But not as often do we have the opportunity to see them in place, in practice. If you happen to be in Little Rock, look behind the Clinton Library for this green gem!

Lessons Learned - Heifer International

Greetings! Now that the grass is green and the rain has begun to fall, I'm feeling like a blogger again. Whew!

In March we traveled to Arkansas and visited Heifer International in Little Rock, Arkansas. Their 24-acre urban headquarters is a far cry from the village agriculture that characterizes Heifer projects. However, the sensitivity to environmental issues is a theme carried through in site planning and development. There are a number of features we'll highlight in the next few weeks. The first is the facility's use of water recycling and rainwater collection.

The building boasts an impressive recycled water and rainwtaer collection cistern that holds 25,000 gallons. This water is used in the building's heating and cooling systems as well as for other non-potable uses, such as toilets and irrigation. The tower is built in to the north wall of the building, adjacent to an elevator shaft, so that its profile doesn't seem out of place with the rest of the structure.

Another feature is the treatment wetland you see in the foreground of the above photo. But we'll talk more about that next time.