Biologist discusses Army Corps plans for the L.A. River
The Los Angeles City Council votes on the Pilot Recreational Zone Program tomorrow. If the zone is approved, the city will build upon the successful Paddle the River program, allowing kayaks to launch south of Fletcher Drive and run about two and a half miles downsteam from Memorial Day through Labor Day. Sorry, that doesn’t include float tubes for fisherman.
One public comment meeting last month quickly turned contentious as dog owners argued against the prohibition of walking their pets along the river, which is one stipulation of the plan. Owners could still walk their dogs on the bike path.
Meanwhile, remember that the next important item for the river will be a public comment period on four proposed plans for ARBOR (Alternative with Restoration Benefits and Opportunities for Revitalization). Here are comments from Erin Jones, a biologist with the U.S. Army Corps of Engineers. She studied ecology and environmental science, receiving an MS from UC-Santa Barbara. After graduate school, she continued with plant and wildlife studies in the field, and has now moved into national environmental policy.
FF: So what is the Corps looking at?
EJ: Basically, the four different options for construction, the Corps refers to them as alternatives, all involve restoration along the river and they are basically of varying scales, and varying costs as well.
We choose a range of options to evaluate in order to see what the impacts are, what the costs are, what the benefits are, at the varying scales. Our smallest alternative may involve a couple of different areas and our biggest alternative involves our whole actions and study area.
FF: Where is that?
EJ: Our largest-scale alternative would have those things, but also add on the confluence of Arroyo Seco, the confluence of Verdugo Wash, the Piggyback Yard, which is in downtown, bigger areas like that, which are more involved in terms of construction.
FF: What does your field work entail?
EJ: What I do in terms of these types of feasibility studies, where we are trying to develop different plans, is to choose one of those plans to try to implement. My involvement is helping to develop these different options and determine what’s going to be the best restoration action, and in what places. I also look at what kind of plants and wildlife were on the river historically and what can we do to restore that same type of habitat.
At this point and time, we’ve come up with just very general plant palettes, we call it, a list of plants that we’d want to see established in those areas. Historically on the river and on the floodplain, there was a lot of fresh water marsh, and there was a lot of cottonwood-willow riparian forest.
FF: How do you gauge historic conditions?
EJ: For this project, the Corps mission for ecosystem restoration is to restore as much as we can to historic conditions, before human involvement, which is difficult and we can’t always do that, but we want to do the very best we can. And so part of that means looking at the history, looking at what was there, part of our research involved acquiring some historic maps from the Huntington Library. They had historic linen maps from 1896 and those maps were very detailed, and they showed the course of the river, at least that snapshot in time, where it meandered, and what some of the habitats were along the river, so we were able to use that, along with other resources, you know different publications, to get a feel for what was here before.
Even at that time the evidence of human settlement was there with crops adjacent the river, and even a little bit of settlement in the downtown area. So that’s where it’s difficult to know what was around, pre-settlement, because finding those records is difficult. But I think we generally have a pretty good idea from the research that we’ve done, so we’ve been trying to use species, for instance, that we know were here historically.
FF: Carp were not here, so would you get rid of them as an invasive species?
EJ: You know at this point in time, I don’t think we’ve talked about active removal of non-native fish. You know when we implement the project that’s something we can look at. I know that construction projects on the Santa Ana River, which I’m familiar with because I work out of Prado Dam, whenever they have diversions for their projects, they pull all the non-native fish out and just leave them on the banks for the raccoons to come and get. At some point, they had to have a bucket loader come, there were so many invasive fish in there, and take them away. You know that’s something that we could definitely look at for this project, the removal of non-native fish during our active construction. For restoring native fish, you need to remove the non-natives.
FF: There are no trout, much less steelhead, currently in the river.
EJ: It’s definitely challenging, especially because the native fish need the cooler temperatures and they need the shade, they need downed wood to create refuge, you know those things aren’t necessarily present in this system. As I said, we can do our best to restore those features in our project. And even stock with native fish to try and restore the populations, but there’s only so much we can do. But I know that some of the features of our project involve trying to mimic native fish habitat with the goal of trying to restore for the natives. Things like riffle pool complexes, and refugia, things like that. Considering the numbers of non-native fish that are in the river now, it’s a challenge, for sure.
FF: So, would the concrete come out?
EJ: Part of the challenge with the project is maintaining flood capacity. This project was built in the early 20th century as a flood control project. And, unfortunately, all of the natural resources were eliminated with that project, so now putting it back we still have to consider safety of people and damage to infrastructure, so removing the concrete fully, we did look at that, and it just wasn’t possible for the cost and for maintaining that capacity, so places like Taylor Yard, we have a big space next to the river, those are the kinds of places where some of our plans look at taking out that concrete bank and just widening the river at that point and really restoring a lot of habitat in those areas. Piggyback Yard is another area in some of our plans where that might be possible.
The Glendale Narrows, wherever these is a soft bottom, that will be left intact. Enhanced, of course, removing arundo, non-natives, that’s a part of the entire program, to remove non-natives, but the Glendale Narrows area is going to be maintained, the soft bottom areas will be maintained.
See you on the river, Jim Burns