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The U.S. Army Corps of Engineers and the City of Santa Cruz have agreed to jointly fund a project to raise the height of the San Lorenzo River levees from one to five feet, depending on location, and to restore riparian habitat along the levees. The San Lorenzo River Flood Control and Restoration Improvements project has been in the works since 1978, and is estimated to cost over $22 million. The City’s share of this cost is $2.7 million.

The improvements were built in several phases, depending on Congressional funding. Congress approved $4.8 million in the Fiscal Year 2000 federal budget and construction of Phase I began in August 1999. Phase I of the project extends from Highway 1 to Water Street and Soquel Avenue Bridge to Riverside Bridge. A small section of the levee was raised in 1998 near Highway 1 behind the new Gateway Shopping Center. Phase II covers Water Street to Soquel and Riverside to the River mouth. Both phases are substantially complete. The State Legislature in 2000 passed legislation authorizing State assistance to the project. This assistance covers a large percentage of the required City share of the project.

The second part of this project was the replacement of the Riverside Avenue Bridge, the northern two lanes of Water Street Bridge, the Soquel Avenue Bridge, and retrofit of the Broadway/Laurel Bridge. The new bridges are higher and allow the freer flow of flood waters. Bridge construction is funded by a separate Federal program and the City’s share has been financed from the citywide stormwater fees, since all City residents benefit from the improved bridges. Bridge construction took place between 1992 and 2001.

The third part of the project was the Laurel Street Extension/Third Street Riverbank Stabilization. This project phase involved the construction of a natural rock-form wall along this section of the river to prevent the collapse of these streets into the river. Vegetation was planted along the toe of the wall adjacent to the river to provide shade for fish and other wildlife.

As of 2009, there are several issues that must be resolved before completion of the project and elimination of the mandatory flood insurance requirement. The first issue involves financing of the project. In 2006, the Corps determined that the City/Corps flood control funding account was short approximately $1.2 million. This determination was based on the Corps’ legal opinion that Congressional legislation granting credit to the City for 2000-2001 improvement of the Soquel Avenue Bridge was not specific enough in wording and needed further Congressional clarification. During 2006 to 2008, the City, working with Congressman Farr, attempted to gain the needed Congressional clarification. However, in each of these years, Congress did not pass a budget but simply extended current funding levels, thus preventing the passage of the clarifying language. Rather than wait for the eventual passage of the Congressional clarifying language, in the spring of 2008, the City paid the Corps the necessary funds to initiate completion of the San Lorenzo Project. In the summer of 2008, the City received reimbursement from the State of California Flood Control Subventions Program for 70% of this payment.

The second issue involves the hydraulic methodology used to design Corps flood control projects, which was changed in 1997 from the “Deterministic Methodology” to a new “Risk and Uncertainty Methodology.” This change was to be applied retroactively to all Corps projects in design and construction at that time. Given the potential impact of this change, waivers were granted nationally to a number of projects, including the San Lorenzo Project, allowing them to continue using the Deterministic Methodology. Based on this 1997 waiver, the Corps used the Deterministic Methodology in the design and construction of the new San Lorenzo River flood control levees.

In September 2007, the Corps Headquarters issued a new directive that rescinded all waivers issued in 1997, regardless of the whether the projects had been constructed or were in the construction phase. City staff has discussed the impact of this change with numerous Corps officials and none seem to understand or be able to judge the impact of this change nationally. After a number of Corps conversations on this topic, in September 2008, City staff requested that the City Hydrologist, Phil Williams and Associates (PWA), conduct a preliminary analysis of the potential impact of the Corps’ mandated Risk and Uncertainty Analysis on the newly constructed San Lorenzo flood control levees.

Based on the finding of this analysis, the new San Lorenzo River flood control levees would need to be increased in height between the Highway One and Water Street Bridges and between the Laurel Street and Riverside Avenue Bridges. The specifics of this change will be subject to further discussions between the Corps of Engineers and the City. Until the specifics of this change are identified, the project can not proceed to its final stage.


Last updated: 7/24/2012 9:00:28 AM