Devil’s Gate Dam, Sediment Removal Proposal

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It is with great relief that I am posting again but this time, there is no video! I think I said this before but the only good thing about putting yourself out there as a rank beginner is that you have no where to go but up (I hope!).

Today’s post is about the LA County Department of Public Works Draft Environmental Impact Report for their “Big Dig” project at the Devil’s Gate Dam in Pasadena near JPL. The public comment period has been extended until January 6, 2014.

The plan is to remove and truck sediment out of the Devil’s Gate Dam for flood-control purposes. Like the previous LAC-DPW project at Arcadia Woodlands back in 2010/2011 (click here and here), the county proposes a large scale, expensive project with little regard for the environmental damage it will cause; a project that will, at best, provide a very short-term solution to an ongoing problem. Last time it was a beautiful, mature oak woodland that fell to short-sighted, out-dated thinking, this time it is riparian habitat. According to the Hahamongna Sediment Cleanout Fact SheetPasadena Audubon Society:

The LA County Department of Public Works plans to remove 2-4 million cubic yards of sediment from behind Devil’s Gate Dam. They will dump the sediment in pits in Irwindale. The project will take five years and will mean 425 trucks per day (that’s 50 trucks per HOUR) driving through local neighborhoods and on the 210 freeway. The trucks will operate for nine months or more per year, six days a week. Between 50-120 acres of riparian willow-mulefat habitat will be permanently destroyed. 

The Arroyo Seco Foundation has posted excellent information about the issue including:

Although our efforts to change the way LACDPW operates failed for the Arcadia Woodlands, the problem with sediment accumulation continues and according to the Arroyo Seco Foundation slide show:

The Current Program

Total Sediment To Be Removed (Next 20 Years)

14 Dams

162 Debris Basins
82+ Million Cubic Yards
Sediment Placement Site Capacity – 11.6 Million Cubic Yards
Cost per cubic yard: $30-60
Total Cost: $3-5 Billion

I wrote a comment letter to the LA County Department of Public Works expressing my concerns about the project and the department’s overall approach. The body is as follows:

To Whom It May Concern:  

I am strongly opposed to the Devil’s Gate sediment removal project as proposed by the LA County Department of Public Works. A slower, long-term plan to gradually decrease the amount of sediment built up in the dam would allow for the development of sustainable flood-control and water management practices. The accumulation of sediment, though exacerbated by the 2009 Station Fire, is the result of inadequate management of the Devil’s Gate Dam prior to the 2009 event. There is still enough capacity in the dam (17%) to move more deliberately to correct for this longstanding, inadequate maintenance. The existing project relies on early 20th Century engineering concepts that predominantly address flood control concerns with no consideration for the accompanying financial, environmental, and health burdens. 

Sediment accumulation in dams along the front-range of the San Gabriel Mountains is the result of an ongoing process – erosion of a steep, young mountain range – being managed with short-term thinking, deferred maintenance, and reliance on outdated engineering solutions. Rivers were channelized and dams, spreading grounds and sediment basins were built to accommodate rapid development in Southern California, with little concern for the long-term consequences of these massive construction projects. 

The repercussions of this type of thinking have become only too clear, and the continued management of our environment and resources as practiced when the dams were built threatens the viability of our region. We have learned that natural forces may be controllable for relatively short periods, but ultimately the only workable solutions are those that are compatible with natural processes and take a long-term, holistic perspective. 

As such, plans to remove sediment using inefficient and polluting practices like trucking it away (“away” meaning not here, though room for dumping is finite and nearly exhausted) are truly baffling. This merely “kicks the can down the road” as the sediment keeps coming, habitat continues to decline, and resources are squandered with little concern about the continued release of greenhouse gases into the atmosphere. 

Nevertheless, the need for flood protection and an adequate water supply cannot be denied. As such, it is critical to include the following considerations in plans to meet these important concerns. 

  1. A long-term, holistic approach that takes into account flood risk, health of the watershed, diminishing resources, and impacts to habitat, wildlife and humans. 
  2. Proposals should make use of natural forces, such as sediment removal through sluicing, rather than going up against them. 
  3. The concept of “waste” is not applicable in sustainable systems. All materials and processes are resources and should be treated as such. Eroded materials that build up in the dams would normally be deposited along the rivers and at the beaches. Engineered solutions should incorporate the value of these materials. 
  4. Rather than a continued record of degrading the land and resources we rely upon, acceptable proposals should have the long-term goal of solving the more immediate problems while improving the condition of the watershed for the future. 

Plowing ahead with an expensive “quick fix” that will disrupt and destroy functioning habitat needed by wildlife and humans for a healthy existence is not in the public interest. A slower, more deliberate and cautious approach could save money and resources while allowing time to develop innovative and effective ways to meet these challenges over the long-term.

Sincerely, blah, blah, blah

Hope you will take the time to comment on this project. We need to stop this kind of destruction!

One thought on “Devil’s Gate Dam, Sediment Removal Proposal

  1. JoYouDog

    Thank you for this post. I sent a link to it to a couple of lists I'm on that are subscribed to primarily by people from this area.

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