Progress on Three Amigos:
Moving Levee Breaching
from Concept to Reality
By Irv Schiffman
The work of riparian restoration alongside California rivers frequently necessitates the cooperation of local, state and federal agencies. Coordination is essential as plans are developed, funding is sought, and implementation is initiated. Sometimes developments move quickly, as in the purchase of the Hidden Valley Ranch, and sometimes things take a bit longer, as in the effort to breach the levees known as Three Amigos.
The disastrous Northern California flood of January 1997 caused forty-one cities to be declared emergency areas and damage to agriculture and livestock was placed in the billions of dollars. In the Central Valley the highest flows recorded since 1862 raced down the Tuolumne River from Don Pedro Reservoir, rushed into the San Joaquin River, overtopped the levees and wiped out farms along the River and breached the associated Federal levees at Reclamation Districts 2099, 2100 and 2102 (later known as the Three Amigos).
(Above) 1997 Levee breach that inundated over 500 acres of the Vierra Dairy.
Following the flood, the levees were partially repaired and a multi-agency task force was established to consider a long-term solution for flooding in the area. The task force recommended that the US Department of Agriculture partner with the US Fish and Wildlife Service to purchase the flooded farmlands in the three reclamation districts and use the opportunity to investigate non-structural flood management alternatives, including the breaching of the three levies.
The breaches would allow river floodwaters to spread over the former floodplain, optimize transient flood storage on the site, and relieve pressure on downstream levees and communities during times of high flows.
The farms were purchased in 1999 and added to the west unit of the San Joaquin River Wildlife Refuge in an area now referred to as the Hagemann, Lara, and Vierra properties, named after the three former farm owners. Perpetual conservation easements were placed on the properties under the USDA National Resources Conservation Service Floodplain Easement Program and the Wetland Reserve Program.
In June 2000 a Memorandum of Agreement was signed amongst the US Army Corps of Engineers, Fish and Wildlife and the State Reclamation Board (now Central Valley Flood Protection Board) in which all parties agreed to the non-structural alternative for the Three Amigos levees. Additional activity included the purchase of flood easements over adjacent lands by the Corps, and the Corps’ agreement to amend the Operation and Maintenance Manual for the subject levees to allow their operation in a permanent breached condition. An environmental assessment for the project was subsequently completed by the Corps.
Two studies by Phillip Williams and Associates in 2001 and 2004 (now ESA PWA) produced a hydrodynamic model of water flows relative to levee breaches including several alternative configurations. Two years later, the 2006 Refuge Comprehensive Conservation Plan endorsed the breaching of the levees as did the Central Valley Flood Protection Plan of 2012.
Meanwhile, in 2002 River Partners began restoration work on the Refuge, planting 777 acres of riparian habitat. Since then some 2500 acres have been restored. Beyond flood protection, the breaching of the levees and the reconnection of the San Joaquin River with the west unit of the Refuge will also assume additional ecological functions: enhancing habitat management by fostering drainage to combat standing floodwaters and rejuvenating the floodplain by providing deep percolation of water every few years and pushing salts down in the soil profile. The flooding of the area would also provide access to rich foraging habitat for salmonids and other native fish.
In September 2013, a draft workplan prepared for River Partners for the breaching of the levees was completed by ESA PWA as part of the Ecosystem Restoration and Floodplain Attenuation Project (ERFA) underway at the Refuge. Funding for this plan is provided through a grant from the state Department of Water Resources Flood Corridor Program. The plan seeks to update the existing hydrodynamic model and preliminary structure design. Stakeholder meetings are presently underway with the participation of federal, state and local agencies and a final project report is due in May of 2014.
It has taken more than 15 years to reach this stage in the process of breaching the Three Amigos levees. While the flood control and ecological benefits of the nonstructural approach remains obvious to all, the technical and coordination complexities have challenged even the most avid proponents. Nonetheless, I hope to report the successful breaching of the levees in a not-too-distant Journal.
The above article originally appeared in the December 2013 issue of the River Partners Journal.