Riverdale Avenue Green Street Under Construction

View of the Riverdale Green Street project under construction. Photo taken from the street-end mini-park, my back to the L.A. River

On my way home from leading a river walking tour for a Pomona College class, I was riding the newly-paved Elysian Valley Los Angeles River bike path (completely rideable, but not quite officially open… but since when do creek freaks wait for projects to be declared open?) I noticed that construction is underway on the Riverdale Avenue Green Street project. The Riverdale project retrofits an existing street to cleanse rainwater runoff before it enters the Los Angeles River. After the jump, there’s more information on the Riverdale Green Street scope, background and other juicy details.

Creek Freak readers may remember our earlier reportage on local “green street” projects, including our advice to Supervisor Mark Ridley-Thomas and our trip to Santa Monica’s Bicknell Avenue. They come in various flavors in various places all over, and there’s a good example at Oros Street – just a few blocks downstream of Riverdale Avenue.

The Riverdale Green Street project extends on Riverdale from Crystal Street to the Los Angeles River in Elysian Valley. At the end of the street is one of North East Trees‘ and the Mountains Recreation and Conservation Authority‘s earliest river access point mini-park projects – today featuring great tall sycamores.

I confess that, though I had heard of this project, I had expected that it was likely to be on the list of state-funded projects currently frozen. I hadn’t heard about finalized plans or timelines or a groundbreaking. So, I was happily a bit surprised to see a city of Los Angeles crew hard at work there this week.

The Riverdale project retrofits one ~500-ft block an existing city street. The finished green street will cleanse and infiltrate runoff before it enters the adjacent Los Angeles River. It’s a city of Los Angeles project, funded by the state Coastal Conservancy. Here’s a description of the project from the California Natural Resources Projects Inventory database:

Riverdale Avenue drains 14 acres of residential property and the runoff currently runs directly into the Los Angeles River where it is transported to the coast at the Long Beach Harbor. City staff have selected this block based on several criteria and will design infiltration units to be installed in the parkways along each side of the street. If successful (and the project will be monitored to evaluate its success) the project will reduce the amount of runoff and improve the quality flowing into the river. With this demonstration project, the Conservancy hopes to help the City of Los Angeles develop a new standard for street design that incorporates low impact development principles.

Overall it’s a good project – and a good precedent for the city of Los Angeles. To date, within the city, these sorts of projects have generally been initiated and built by nonprofits (mostly North East Trees, TreePeople, and the Los Angeles and San Gabriel Rivers Watershed Council) and by state agencies (mostly the Mountains Recreation and Conservation Authority.) Riverdale was undertaken at the city’s initiative – thanks in large part to Board of Public Works commissioner Paula Daniels! It was designed by city staff, and is being constructed, and will be maintained by them – so it’s good to have that precedent, knowledge, skills, experience, etc. in-house as the city moves forward with other street retrofits and other watershed management projects.

My critique of what I can see of the project (and this is also true for the aforementioned Oros Street project – check out photos of what’s going on undergound there) is that it appears to rely on out-of-site out-of-mind buried stormwater devices. Street runoff water collects in an infiltration gallery – basically an open-bottom gravel-filled box underground. This slows the water down and allows it to percolate into the earth – thus recharging groundwater, preventing pollution, and reducing flooding. The trouble is that you’ll have to read a sign (or L.A. Creak Freak) to learn this… ’cause it’s all buried.

My preference (as I mentioned earlier) is for projects that are more readable on the surface. Projects that reveal natural processes, instead of concealing them. These can take a little more room… but they tend to be both greener and better tools for educating the public. Examples of these sorts of more open green projects would include the Bimini Slough Nature Park and creek daylighting.

I haven’t seen the actual final designs/plans for Riverdale, so hopefully I will be pleasantly surprised, but, from what I saw onsite, I suspect that the important processes there will be all buried. A greener and more readable project at the site might have removed the last ~25 feet of concrete at the end of the street (in the above photo where all the gravel is) and allowed street runoff to settle into exposed earth there – perhaps in some sort of creekbed bio-swale with native vegetation. In large storms, excessive runoff would overflow into the strormdrain, which could include the underground infiltration devices.

Overall, Riverdale Avenue is an excellent project and an important precedent (and I am too harsh a critic.) I look forward to its completion, and to the city moving forward with even greener projects in the future.

One more shot of the city of Los Angeles crew constructing the Riverdale Avenue Green Street