September 12, 2012 § Leave a comment
This Friday, September 14, 2012 at 7:30 pm author/activist Cleo Woelfle-Erskine gives a public talk on his new book Creating Rain Gardens. The talk takes place at L.A. Eco-Village, 117 Bimini Place, LA 90004. There’s a requested admission of $5 to $10, but no one turned away for lack of funds. Reservations recommended, contact eco-village: crsp [at] igc.org or 213/738-1254.
October 5, 2011 § 1 Comment
Rain always means going out to watch the water rise, and this morning a friend and I hustled out to Ballona Creek to the check out the recently completed rain gardens in action. I posted about them here and here. When I got home a few hours later, the County’s rain gage indicated that Ballona Creek near there had received 0.8″ – so this was a healthy first test for the rain gardens. Santa Monica Bay Restoration Commission staff were out taking samples and observing its performance as well – and now doubt we will all be eagerly watching how the gardens adjust and adapt to the season’s flows.
May 30, 2011 § 4 Comments
A flash from the past! I created this 8-page Landscape Rainwater Harvesting booklet for a workshop I taught the summer of 2008. The class was held June 14th 2008 at Los Angeles Eco-Village. The main activity was building las trincheras – an urbanite-terraced rainwater harvesting garden that I wrote about here a while back – and in this vid. It’s funny, the workshop was pre-creekfreak – the month before Jessica and I got started with L.A. Creek Freak in July 2008.
March 3, 2009 § 11 Comments
From mid-January through last week, I’ve been working to construct a rain garden in a friend of mine’s mother’s backyard. This is my first real paid landscape job, and the first time I’ve been in charge of something in someone else’s yard… so there are plenty of lessons learned.
I’ve gardened for a long time, and, for the past couple years, I’ve been experimenting with creating passive rainwater harvesting earthworks. I mostly make these with retaining walls made out of stacked un-mortared broken concrete – called “urbanite.” Urbanite is an excellent material that’s locally free and abundant. Re-using it diverts it from landfills. The water harvesting earthworks are very much inspired by the work of Brad Lancaster, whose books I highly recommend for anyone looking to do this sort of stuff at home.
I was invited to try to solve a drainage problem at the site. The roof downspout empties onto a sloped side yard. The surface of the sloped yard looked like dirt, but it’s actually decomposed granite (or something similar.) The water from the downspout was creating a little stream that ran downhill into the backyard, where the sediment and water build up on a paving-stone patio. The owner had set a large metal basin below the spout during rains, and had set up small temporary stacked brick check-dams in the path of the water flows.
The area I had to work in is somewhat narrow, as there’s a gate right near the downspout, and a stepping stone path about 4 feet from the house, paralleling the wall of the house. Another complication is that the site is on the north side of the house – which is shady. Additional shade was provided by a deciduous tree growing at the base of the slope of the side yard.
My friend’s mom had asked a landscaping contractor to solve the problem. His proposal was to dig a big pit and attach a pump which would push the water uphill into the street in front of the house. I suggested to the her that rainwater was indeed a resource and that we should try a solution that would detain and infiltrate that resource on site. Pumps require energy input, and occasionally break down.
I wrote up an estimate, got my advance, and started assembling materials. There wasn’t really any soil to work with at the site, so I ended up buying bags of soil at a local garden store. I purchased shade-tolerant, drought-tolerant natives at the Theodore Payne Foundation nursery (plants listed below.) And I started to scavenge up broken concrete wherever I found it.
I hired my friends to help me. Thanks very much to Bobby, Erik (half of the Homegrown Evolution blog team,) and Hunter, for working hard and not minding me bossing them around (or at least not complaining too much.) A big rainstorm was due at week’s end, so I was motivated to get the project completed. Not only did I want to test the rain garden’s functionality, but I was planting native perennials, so I wanted to plant early enough for the rains to help them get established. In three and a half full days of work, we got the rain garden installed.
We started at the lower end and worked upwards level layer by level layer. We built up level beds out of broken concrete and brick. These were un-mortared, thought we did use mud between them.
We put a row of brick running level – mostly just for color variety (there was a pile of bricks lying around on-site that were offered to us.)
The finished planter had three stepped terraces. Areas along the top were designed to serve as seating.
Though it’s a rain garden, designed to infiltrate water, there’s really no surface flows expected. The level terraces encourage the water to spread out and to soak in. The overall bed acts like a sponge, absorbing the flows from the downspout, causing the rainwater to soak the plants roots and to seep into the ground.
The downspout poured onto a tilted piece of concrete which was intended to convey the flow of the water into the matrix of the bed (see photo below right.)
We planted the following, sprinkled a native wildflower seed shade mix, and looked forward to the coming storms: (from left to right) Bert Johnson manzanita (Arctostaphylos edmunsii ‘Bert Johnson’,) coral bells selection (Heuchera ‘wendy’,) rose snapdragon or wild snapdragon (Antirrhinum multiflorum,) California buckwheat selection (Eiogonum fasciculatum ‘Bruce Dickinson’,) Mexican rush (Juncus Mexicanus,) Bolander’s phacelia (Phacelia bolanderi,) shagged haired alum-root or Idylwild rock flower (Heuchera hirsutissima,) Pacific coast iris “moonlight,” California buttercup (Ranunculus Californicus,) coral bells selection (Heuchera U.C. Berkeley,) Pacific coast iris “sky blue and white,” old la Rochette heuchera and another iris moonlight. In addition, I added some California yarrow and some aloe vera (which is the only not-necessarily-native in the bunch.)
And that’s where things got interesting…
Two days later, I made my way over to the client’s house during a large rainstorm, smug in my overconfidence that I was going to see the bed functioning beautifully… and that I would soon become the local water harvesting guru, besieged with requests to build all sorts of beautiful garden beds all over the southland. When I got there, during a lull in the storm, I discovered that rain had collected at the upper end of the raised bed. The rain pooled there, then, to my dismay, overflowed along the perimeter of the bed… more-or-less completely avoiding the beautiful bed I’d laid out for it.
The flow of the water was digging a little gully around the project… and, of course, depositing plenty of sediment in the lower patio area.
When I initially noticed this failure, my first thought was that my rain bed hadn’t failed, but that I just hadn’t read the site well enough. Brad Lancaster calls for long and thoughtful observation before undertaking this work. I figured that my work was perfectly fine, and that the nearby sloped driveway (and probably even the neighbor’s yard) was probably contributing too much runoff into this area.
That’s when the rain starting coming down again… and I noticed that the downspout’s water was entering the bed, then immediately exiting through the upstream bed wall. And I was observing this at this point the rain was flowing very little. The rain, much smarter than we humans, had found a short-cut, and staying at the very edge of the bed, then exiting it, pretty much entirely bypassing the bed. So much for my reputation as a water harvesting expert! One mistake I’d made was that I’d tried to hold the rainwater fairly high off the ground, in a pretty leaky vessel… so when the water found a small opening, it quickly flowed through that leak, clearing some soil in its way, reinforcing its path, creating a full-fledged bypass.
I hastily convened Erik and Bobby out on site again, and we took apart the entire upper end of the project and removed a layer, so as to hold the rain closer to the ground. (One nice feature of working with unmortared urbanite is that it’s easily taken apart and reconfigured.) We reconfigured the new upper end to usher downspout water into the center of the bed. The gutter basically empties onto a ramp, and at the base of the ramp is a flat piece of permeable concrete surrounded by small rocks. This set-up serves to deliver the rainwater into the middle of the upper bed, and to spread it out a bit. In addition, we reworked the walls of the upper bed. We used larger concrete pieces, and put them together as tightly as we could – with fewer and smaller gaps between.
We also brought some clay soil from my home and we used the clay to plug the gaps between chunks of concrete. There was practically no clay in the topsoil I’d purchased, nor in the decomposed granite at the site, so the mud we had used as mortar was more permeable than a healthier soil mix that does contain some clay. As the clay gets wet, it becomes less permeable, so it keeps the gaps filled, preventing leaks. In the area where the water first spreads, we used a lot of clay, both between layers, and between pieces of concrete within each layer. For the rest of the bed, we inserted clay to patch up obvious gaps we could see.
These fixes more-or-less worked. The lowered bed, the clay and the ramp-spreader have survived a couple of good-sized storms without any major failures. I had been thinking that, had it blown out again, I might need to do some sort of “level spreader” – perhaps a rock-filled gutter 3-4 feet long, with holes in the bottom. This would serve to spread out the flow more evenly. Unfortunately I don’t think it would look that good, though eventually the plants could camouflage it. So far, it doesn’t appear that it’s needed.
In a good sized storm, the whole bed does leak… slowly. And is is meant to… but it hasn’t had a big blow-out yet. Unfortunately, though the client likes the look of the project, it hadn’t entirely solved the problem it was supposed to. There was still some water and sediment getting down to the patio below, but much less than before.
In working on this, I’ve come to the conclusion that it’s actually a somewhat difficult task to re-spread out water after we’ve concentrated it. The roof and gutters concentrate water into the downspout, so the biggest task in detaining and infiltrating that water is to undo that concentration. This is analogous to watershed management and river restoration. It’s much easier and less failure prone to disperse interventions throughout the watershed, as opposed to intervening in the river corridor. It’s worthwhile to work on smaller interventions in the upper watershed, which would be less prone to catastrophic failure when compared with projects that deal with huge volumes already concentrated in the lower portions of our rivers and creeks.
When the project was leaking a lot, I had re-built the temporary stacked brick dams at the downstream end, below the bed. Not feeling quite as confident in my prowess, I left these temporary dams in place for nearly a month, while I kept an eye on my new iteration to see how it was working. When I examined them, there was still some sediment gathering behind them, though not a lot, and no serious gullying like there had been when the first real blowout occurred.
I decided that it would be worthwhile to make those small temporary dams into small permanent stepped terraces. Using more urbanite and bricks, I created a couple of level “smile berms” (also called “boomerang berms.”) These parenthesis-shaped terrace walls detain and slow down the water still leaking and let it overflow into a lower garden area, instead of going into the patio. I just built these last week and I am looking forward to seeing them tested in the rains predicted this week. We’ll see.
Some lessons learned so far:
– I think if I had the whole project to do over again, I would do the whole bed more as a series of lower stepped smile berms, instead of raising it up as high as I did. (The intial three-terrace version really stuck upward at the upstream end. It was nearly three feet high right near the downspout; now it’s about a foot and half.) When working with water, keep it close to the earth. This change would eliminate most of the seating areas, but I suspect that it would work better. It would better spread out the water for infiltration, and minimize the severity of failures (with many low berms, if one berm fails, then the next berm should be able to catch its overflow.)
– Though I like decomposed granite as a natural-looking permeable material for use in building public parks (as North East Trees and others have done along the Los Angeles River,) I hadn’t really worked with it before. I was a little surprised at the way it behaved. It’s basically little rocks, so the water doesn’t really stick to it at all. It’s permeable, but its infiltration seems to be more like gravel than soil.
– There’s no substitute for long and thoughtful observation. To do rainwater harvesting earthworks like this, I need to go and see what is really happening while it’s actually raining. Even my observations immediately after a rains were colored by my own hubris. Rainwater won’t necessarily go where I expect, but will find the path of least resistance.
– Enjoy failures… that’s where we learn and adjust.
– Add some extra time onto your estimates whenever you do paid landscaping!
February 23, 2018 § Leave a comment
The Celebratory (also, yes, the Nerdy): Water LA 2018 Report
WaterLA , a project spearheaded by the River Project, champions making watershed management local. Hyper local. Your front yard local. The team there combines community outreach with effective, tested permaculture and landscape design techniques to harvest and retain water in yards and street planting strips. Rain gardens, rain barrels, grey water systems and permeable paving are among the solutions used at multiple sites across LA’s Valley. WaterLA organizers locate community members ready to pitch in and engage in work parties, so that everyone’s working together – building community while building resilience.
This year’s WaterLA Annual Report, then, is a celebration of the gains to individuals, families and our water supply delivered through participation in the project. You see, all those small projects add up to groundwater enhancement, and reductions in peak runoff when it rains – dampening the effect of most floods. The Annual Report quantifies water savings and relates project costs to other, more costly, regional approaches currently in use. Native plant and permaculture folks may be excited to see the conversions of lawns to habitat and foodscapes, community-minded folks may find some inspiration in its projects, and fiscally-minded folks may be encouraged to see creative, affordable solutions to expensive regional problems. A worthy project that would benefit all if it could be applied on a larger scale.
October 24, 2014 § Leave a comment
When I passed this truck on the 210 freeway this afternoon, I wondered what watershed these huge pipe sections were destined for. I thought about all the rain gardens, bioswales, wetlands, stream restorations, urban parks, and urban biodiversity that could be created if we had spent the $$$ used for the digging of trenches and laying of such massive pipes on something that actually benefited the everyday quality of life of urban residents, that replenished local groundwater supplies so we can reduce our dependence on imported water, while nurturing native riparian and wetland biota, while improving the quality of water in our bays, while providing non-electronic entertainment for all the kids that live in parts of the city that otherwise have no easy access to parks, while still providing flood control benefits.
I wondered why we still invest in stormwater infrastructure that perpetuates a cycle of dependence on more infrastructure. Just like it has been shown that building more and wider freeways and roads results in stronger dependence on cars; adding more impermeable surfaces in a watershed (buildings, asphalt parking lots, roads) results in the need for increasingly extremist drainage infrastructure, like super gargantuan pipes…
Tell me these pipes are meant for something other than to convey one of our urban underground streams toward the ocean in a way that prevents their use by native biota, and which prevents us nature-starved city people from experiencing the physiological and public health and microclimate benefits that urban greenery provides. Tell me that these pipes are being transported because urban streams all over are being daylighted, and that using bigger and bigger pipes to convey a precious resource like water toward the ocean is recognized as a quaint part of our historical past. Tell me underground pipes are being replaced by wetlands, infiltration zones, and streams, and that the reuse of pipe sections that used to convey urban streams is now choice material for architecture for the homeless, where the thick concrete walls of pipes are perfect as thermal mass that creates passive climate control… or that these pipes are being reused as wildlife crossings under freeways…. or that sci-arc students are making them into the new modular architecture? pod hotels? something…..
October 10, 2011 § 4 Comments
Creek Freak’s Jessica Hall has the money line in Emily Green’s L.A. Times Dry Garden column last Friday:
This much I know as I estimate rainwater and consider how to manage it: Although the new system must function, it also must be beautiful. Earlier in the year, as I was babbling proudly to garden designer Jessica Hall about the plan to whisk half the roof water through concealed piping to the rear orchard, she asked, “Do you want to celebrate the water?”
A strong degree of brute efficiency will clearly be necessary, but as the first rains wash into L.A. County, the answer to Hall’s question is an unequivocal yes. Yes!
Read the full article here. Thanks Emily Green and Jessica Hall!
(Speaking of celebrating water, albeit in bigger more institutional ways, check out Jane Tsong’s Creek Freak article on Seattle’s new wastewater facility, also covered at Circle of Blue.)
May 13, 2011 § 5 Comments
A few posts ago I mentioned the Rain Gardens being built on Ballona Creek. I am working with the contractor on the project, and so have been fortunate to observe the stages of implementation. We are still weeks away from completion.
Several weeks ago I took a walk along an excavated area of the right of way. These excavations will be filled with a soil-compost mix in terraced bioswales. But the walk along this opened-up bank was oddly poignant, revealing layers of Ballona Creek that had itself been excavated and then piled up here. The sense of Ballona as a once-natural watercourse became more tangible seeing pockets of cobble and sand that must have been in the creek’s bed at one time, carried from the Hollywood Hills, tossed and gently moved over decades until deposited out of the channel to build up the flood control channel. It was as moving to me, imagining the life that once flourished here, and as haunting as visiting the ruins of Chaco Canyon or any archeological site.
This bit of geology will be closed back up soon as walls are built up, filled and planted. But perhaps someday those cobbles will be free to roll down a restored river – when we’ve finally embraced our waterways as part of the urban fabric.
November 19, 2010 § 1 Comment
When Creek Freak posted our article about the city of Los Angeles’ recent Riverdale green street project, we received a comment from AHBE – a landscape architecture and environmental design firm located in Culver City, headed by Calvin Abe. I’ve been aware of AHBE from their support of Friends of the L.A. River, their creative contributions to Park(ing) Day and their rain garden projects – shown in more detail below. AHBE’s video (above) gives a good context for green streets, then profiles North East Trees‘ Oros Street and AHBE projects downtown and proposed for South L.A. « Read the rest of this entry »