Flood Damage At Manzanar NHS Could Have Been Much Worse

UPDATED with new photos of flood damage released on July 27, 2013. Manzanar’s auto tour road re-opened on July 29.


LOS ANGELES — After news spread of flood damage at Manzanar National Historic Site, the result of heavy thunderstorms on the night of July 22-23, 2013, there was concern, generated by photos posted on Facebook later that day, that the damage was much more extensive than the National Park Service had initially believed.

However, while the damage is significant, those fears have proven to be unfounded.

“The real fortunate thing is that it wasn’t a huge torrent that would’ve swept a person standing there away, where lives would’ve been lost, or pick up trucks would’ve been moved,” said Les Inafuku, Superintendent, Manzanar National Historic Site. “That did happen down south, in Olancha. Some people in a four-wheel drive [vehicle] were taken for a ride, two days prior [to the flooding at Manzanar].”

“It happened in the most fortunate way it could, really,” added Inafuku.

On the night of July 22-23, 1.06 inches of rain fell at Manzanar, according to Alisa Lynch, Chief of Interpretation, Manzanar National Historic Site. But that was nothing compared to the rainfall way up in the Eastern Sierra, to the west of Manzanar.

“The flooding occurred on United States Forest Service (USFS) land, over which the Los Angeles Department of Water and Power (LADWP) has no control, well to the west of LADWP land,” said Chris Plakos of the LADWP’s Bishop Administrative Office. “Water overflowed the creek banks and flowed east across USFS land, Bureau of Land Management (BLM) land, and some LADWP land, before flowing to Manzanar.”

Like they do for virtually every creek and stream draining the eastern slopes of the Sierra Nevada, LADWP diverts Bairs and Shepherd Creeks, allowing their waters to spread over the desert floor and recharge the groundwater table for later pumping from wells. That water eventually flows into the Los Angeles Aqueduct for delivery to LADWP customers in Los Angeles.

“It was a heavy thunderstorm,” said Inafuku. “LADWP’s diversions would have failed. There’s no doubt about that.”

“High flows were the result of nature causing heavy thunderstorms throughout the Eastern Sierra Mountains over the past week,” Plakos noted.

In fact, the flood waters coming down from the Eastern Sierra not only overflowed the banks of Bairs and Shepherd Creeks, but, as discovered by Manzanar National Historic Site archeologist Jeff Burton, they actually created new channels, both running through Manzanar (see Google Earth map).

Flood waters not only overflowed the banks of Bairs Creek (to the south) and Shepherd Creek (to the north), they cut new channels that flowed through Manzanar, as indicated by the blue lines in the photo below from Google Earth.

Although the flood waters generated by the heavy thunderstorms were the cause of the damage, Inafuku noted that LADWP has done some mitigation work in the past to help prevent flooding at Manzanar, cleaning out upstream sand traps on BLM land that blocked Bairs Creek.

“LADWP promised to do what they could to prevent flooding [in 2010, a heavy snow year],” said Inafuku. “Sure enough, there was no flooding at Manzanar.”

Given that LADWP has done this sort of work in the past, Inafuku believes that they can do more to protect Manzanar.

“It’s something upslope that needs correction,” he stressed. “There’s no doubt about that. We intend to speak with LADWP about preventing future flooding.”

Aside from their comment on where the flood originated, LADWP has not responded to requests for comment on their water spreading activities on Bairs and Shepherd Creeks, or about their past flood prevention work upstream from Manzanar National Historic Site.

Inafuku spent much of the day on July 25 out on the site with his staff, assessing the damage, with flood waters having mostly receded.

“One of the streams [Shepherd Creek] came at us just north of the hospital complex (see map above; click on the map to view a larger image and/or download a printable version),” said Inafuku. “It came across the road at Block 34, where that mess hall garden is, and then right on down towards the orchard and Merritt Park—the orchard is fine, by the way, and then, the hospital garden is fine, too. But Block 34 is a mess.”

“[Flood waters overflowed Bairs Creek] on LADWP and BLM land, snaked back and forth, came down our access road, and then, it went across the road to Block 12 (see map),” added Inafuku. “The garden is buried. You can see the rocks—the pond looks like it’s solid ground, but if you were to step on what looks like solid ground, inside the perimeter of rocks for the pond, all of a sudden, you would drop a foot to 18 inches to the mud, because it’s just a layer of dirt on top of the water.”

But wait…there’s more.

“From Block 12, the water came to the entrance road area, and then there’s a little bit of water along the entrance road near the sentry posts and the historic entrance sign (see map),” Inafuku noted. “Then, it flowed into a drainage pit next to Old Highway 395 (Manzanar frontage road), and then flowed north and south in the pit.”

“The Block 9 garden was spared, but water from that flow above Block 12—one fork of the water went out into the nearby road, so we had some minor damage there (see map),” Inafuku added. “But without a grader—we used a front-end loader—we’ve been able to flatten the road again, and every day, we’ve been out there, flattening more of the road. The road looks really good, actually.”

Despite that, at press time, the auto tour road remains closed.

“For the auto tour road, the flood has [pushed up] the day when we need another road project where we haul in road base—the road is not just sand,” said Inafuku. “It’s a mixture of sand, gravel and a binder. Enough of the road base has eroded over time, but this has accelerated that, for sure.”

The iconic Merritt Park, with its well-known garden, has been covered in silt.

“The water did not make a straight attack on Merritt Park,” Inafuku noted. “It pooled elsewhere and backed up into the pond. It’s not like a big ditch was dug right into Merritt Park by an erosional stream.”

“The pond has a significant amount of water, but what is in the water is a combination of sand, like you would expect, and silt,” Inafuku added. “It’s really silt that has come in. Lots of it. Because of the silt in the bottom of the pond, it’s not draining.”

The pond has also suffered damage to its banks.

“The other thing we could see, right off the bat, because [the pond at] Merritt Park does not have a cement lining, like some of the other garden [ponds] do, some of the bank has fallen into the pond, and some of the rock has fallen into the pond, in three places,” said Inafuku. “It’s not a lot of rocks, but it’s going to require building the bank up again before we move the rocks back up. Then, the question becomes, how are we going to do that, because if it’s just dirt, it’ll fall in again, so we’ll need, at least, a soil cement of some sort, to solidify the bank.”

Making this incident even more tragic is that the gardens that have been covered in silt were recently excavated and rehabilitated by volunteers and Manzanar staff. That work will not only have to be done again, but this time around, it will be even more painstaking.

“We’re going to have to have more Jeff Burton-led excavations, for sure,” Inafuku explained. “The various ponds and gardens will have to be excavated again, and then we’ll have to use brushes to clean the rocks of that silt. But you’ll only get so far doing that, so then you’re going to need to use some water. Then there will be some drying time. It won’t be a quick process.”

“Sand doesn’t cement to itself, so a shovelful of sand is easy,” Inafuku elaborated. “We’re not quite sure how easy it will be to remove the silt [a combination of sand, water, and organic material]. It’s not work that can be done with heavy machinery. It’s going to have to be done by hand.”

Despite that, Manzanar staff is encouraged by the quick public response to the flood damage to the gardens.

“The mud has buried years of work done by NPS staff and volunteers,” said Lynch. “We are grateful that many people have volunteered to help us remove the mud.”

“There are people who have participated in previous volunteer excavation work of the various gardens at Manzanar who want to come back and fix things, right now,” said Inafuku.

For those wondering about the Manzanar cemetery, where the famous monument (Soul Consoling Tower) is, and where the annual Manzanar Pilgrimage takes place, Inafuku had some good news.

“The cemetery is fine,” he said. “Flood waters missed the cemetery completely.”

Inafuku indicated that Burton hopes to have a damage assessment completed by the end of the day on July 26, but his draft report will have to go through a review process before the final report is available to the public.

Nevertheless, it is now clear that the damage could have been much worse.

“There was no major damage,” said Inafuku. “The way to look at it is that we have a layer of silt now.”

Inafuku warned that there are public safety concerns for the flood-damaged gardens, which he noted are now closed to the public.

“We’re building ‘area closed’ signs right now, for the Block 12 garden, the Block 34 garden, for Merritt Park, and a couple of other small areas,” he noted.

Gann Matsuda, who writes from Culver City, California, is the the Manzanar Committee’s Director, Communications and Social Media/Web Editor.

Unattributed views expressed in this story are those of the author, and are not necessarily those of the Manzanar Committee.

LEAD PHOTO: Flood waters from heavy thunderstorms in the Eastern Sierra mountains to the west of Manzanar National Historic Site during the overnight hours of July 22-23, 2013, reached Old Highway 395, which now serves as a frontage road for Manzanar NHS. NPS Photo/Jeff Burton.

Flood Damage At Manzanar National Historic Site, July 22-23, 2013

Photos by Jeff Burton, courtesy National Park Service. Click on any photo to view a larger image, and to scroll/click through the gallery.

 

More Flood Damage Photos, July 27, 2013

Photos by Jeff Burton, courtesy National Park Service. Click on any photo to view a larger image, and to scroll/click through the gallery.

 

Related Story/Photos


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