Saturday, January 13, 2018

From trickle to torrent in minutes -- a paddler's tale

Testing the new spillway at Folsom Dam (Youtube photo from late 2017)

It began like another uneventful winter day on tranquil Lake Natoma…. 

Karen paddling into "big pipe" on a typically calm day (2009)
….as we pushed off from Nimbus Flats on Friday (1/12) and paddled into “the big pipe” just across the lake. Of course, we had no idea that the new spillway at Folsom Dam, about seven miles upstream, had opened minutes earlier.  The outflow shot from around  2,000 cubic feet per second to more than 14,500 cfs – and was coming straight toward us.  

To put it another way, that was about 6.5 million gallons a minute -- enough to fill about ten Olympic-sized swimming pools. A significant amount of water, even in a bathtub
the size of Natoma. Then add the funnel factor  -- ‘the big pipe,” a culvert under the bike trail, and the only paddling access into a popular nature area.

What NorCalYak pal Karen and I experienced during the next hour certainly didn’t compare to the Oroville Dam fiasco, or the recent deadly mudslides in Southern California. But it was pretty unnerving. And left us wondering: Why did the Bureau of Reclamation release so much water so quickly at the start of a holiday weekend – without clear public  notice?

In 9 years, we never encountered notable current in this area...

The area around and behind “the big pipe” is off the main lake and at a slightly higher elevation, so the typical problem there is low water.  In nine years of paddling this area, neither Karen nor I ever encountered any notable current. The lake level was high, but not unusually so. We reached the pipe around 2 p.m.    

Soon after we passed through, Karen spotted a river otter. We went on to see a regal blue heron and some large turtles, heads extended like periscopes, sunning themselves on branches that poked out of the water.  As we passed one spot, a large branch just below the surface scraped our hulls.  Shallow, as usual.

But after we cruised the marshy area for 20-25 minutes and headed back toward the pipe, we saw turbulence ahead. Large tree branches just below the surface a few minutes earlier had disappeared. Roiling water grabbed at our 17-foot sea kayaks. The last 50 yards to the pipe had us veering back and forth.

 My first thought:  There's been some kind of mishap at Folsom Dam...

Water in the pipe itself had risen a good two feet or more, gushing and swirling as we’d never seen before.  (My first thought: Oh crap, there’s been some kind of mishap at Folsom Dam.)  We struggled to maintain a position a few yards behind the pipe and considered the possibilities: How long would this last? Would it get even worse? Could sundown become part of the equation?

Karen’s a very strong paddler, but I was wearing a dry suit, so we decided I would take the lead. Before I even got into the pipe, the current spun my yak around and nearly capsized me.  If that had happened inside the pipe, it would not have been pretty.

Lowering my skeg to steady the bow, I went for it...

Lowering my skeg to steady the bow, I went for it.  Paddling hard, it still took three minutes or so to make the eight or ten yards to the pipe’s mouth. Then my boat stalled in a “hump” at the entrance, perhaps created by flow against the culvert’s concrete lip. Not quite a standing wave, but a swell that made me feel like I was paddling uphill. And getting nowhere fast for perhaps two minutes.  Then I somehow broke free and cleared the pipe, making my way out to the nearest bank.

Karen also stalled at the “hump” but couldn’t paddle over it. The current swept her back through the pipe and she hugged the brushy bank to hold her yak in position.  We yelled back and forth a bit. The best option seemed to be to portage over the bike trail to calmer water.

A few minutes later, I was stumbling up a steep bank as close as I could safely get to the pipe when I met two trail walkers, Justin and Amber.  Justin offered to help get Karen’s kayak out of the water and up the brushy bank to safety. (And a tip of the NorCalYak cap to Justin.)

By about 3:30 p.m. we were secure again and looking to re-launch. I retrieved my camera phone from a dry bag and made a video from the bank.  The flow had slowed considerably but was still fairly strong. I wasn’t about to approach the pipe on the water again for a closer video shot.

The experience seemed a bit surreal. But we found data to back up this story. The California Data Exchange Center operated by the state Department of Water Resources puts the dam operation numbers online: At 1 p.m. on Friday, Folsom Dam was releasing 2,029 cfs. An hour later, it was 14,506 cfs. A couple of hours after that, it was back in the 2,000 cfs range.

To be fair, few other areas of Lake Natoma could have been affected so dramatically.  But I wondered if anyone was paddling up the mini-canyon between Negro Bar and Folsom Prison, and what happened there. A power boater in the open water told us he noticed nothing amiss -- to be expected when water can spread over a larger surface area.  

Back at Nimbus Flats, we encountered a state park ranger and told her about our close call. She was nonchalant.  Oh yeah, she said, I was up at Folsom this morning, and they’re testing the new spillway. Wouldn’t it be a good idea to let people know about these releases? Not our job, she replied. True enough, ranger, but you’d probably have to help recover bodies from the lake, if it ever came to that.

© Glenn Brank, 2018