May 1, 2009 § 16 Comments
The stream mapping is complete, but that image of a stream’s flow spilling over and down a road stays with me, challenging the conventional wisdom about “urban slobber.” If you’ve ever been out to the Kuruvungna Springs at University High School in West LA, you’d know that springs gush forth thousands of gallons of water every day, and this water doesn’t stay on site – what used to feed a stream now flows into a storm drain that feeds into the Sepulveda Channel and then Ballona Creek. Other springs on site are directly capped, with only a manhole cover to hint at its presence. So it’s not just headwater drainages whose flows get lost to these underground conveyances, it is also springs, and yep, LA still has some.
Old stormdrain maps sometimes can offer clues to the capped springs. This image here is of a “spring relief” area in the Silverlake/Franklin Hills area. I have seen a few – not many – of these areas on these old maps.
Don’t get me wrong – plenty of urban slobber really is overspray from urban slobs. But if we manage the springs’ flows that way, we miss something essential and precious about our native ecosystem, and we miss out on opportunities to restore pockets of habitat in the city. And you know, springs hope eternally.
April 17, 2009 § 4 Comments
I am in the midst of a depressing exercise of stream deletion, viz. the image at right. Once again, mapping streams of LA, and then deleting them to be able to say with some reliability what’s left. It’s painstaking as well as simply painful.
While simultaneously reaching for some (legal) numbing agent and zooming in a former stream on the north slope of the Hollywood Hills on GoogleEarth, however, I noticed urban runoff dribbling down the gutter. I was looking for any chance that a stream channel persisted (further down the road, there was in fact an open semi-channelized waterway – so it wasn’t entirely empty hope). Curious, I followed the runoff upstream, till I arrived at what was clearly a stream. And it is pretty apparent that the runoff is coming from the stream. The next canyon over showed a similar pattern of runoff. And it was in the month of July, so not seasonal, this.
I often find myself wondering during conversations about “urban runoff” how much of it is genuinely from some idiot watering his or her driveway. True, we have no shortage of waste from poor water management, and plenty of it is polluted.
But here is interesting evidence that some runoff is from a stream just being a stream – and that it would still be flowing in a stream if we hadn’t rammed a street through it. Suggestive to me, anyway, that we might want to have a policy for managing this urban runoff a little differently than treating it like wastewater.