Institute for Crisis, Disaster, and Risk Management

Crisis and Emergency Management

January 2004 Volume 5 - Number 4

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Mitigation...

A Summary of the Napa Flood Control Project
By Uloaku Echebiri

Traditionally, flood control as a form of mitigation has focused on constraining and controlling a river. These structural controls have always been controversial as a mitigation tool, as they have both positive and negative effects on the areas they are not protecting; they are used to control the hazard and not effectively reduce it. Today, flood control districts, city, county, and environmental groups are seeking new approaches to flood management that combine natural and man-made alternatives. This is essentially the idea behind the Napa River flood protection project. Rather than suffocating the River with concrete contraptions, the project will restore six miles of the River and its watershed. It intends to minimize the disruption and alteration of river habitat and maximize environmental restoration and enhancement throughout the wetland. The project is designed to protect the Napa valley from the 100-year flood – an event that has a 1-in-100 chance of occurring in any given year and create a flow in the Napa River more than 30 times the normal flow.

The Napa River project does not rely on a single approach but combines multiple strategies in a way that makes optimal use of engineering, ecology and different funding sources. There are many aspects of floodplain management in the project, which includes, among others, emergency planning, bridge replacements, home elevation, wetland creation, setting back levees, and creating a flood bypass.

The 1995 concept developed was one of a “Living River” where the project, as well as protecting the community from flooding, would also allow the river to nourish plant and animal life, while bringing new vitality to neglected riverfront areas. Where the Army Corps of Engineers had initially proposed floodwalls and levees, the coalition, made up of the citizens of Napa County and a number of Agencies, proposed terraced marshes and broad wetlands, and where proposals for dredging the river deeper to allow it carry muddy water faster, the coalition wanted to make it wider by returning much of its floodplain. If these lands were restored to wetland condition, those areas would be designed to absorb major flood events with little or no harmful effects. Essentially the plan is to ‘let the river be itself.’

The plan also includes reforesting some riparian areas with a variety of trees, which will create good wildlife habitat, prevent weed and brush encroachment on river channels as well as reduce bank erosion. Additional goals of the project include creating bridge replacements, constructing a flood bypass, river trail, improved recreation opportunities and relocating buildings away from river banks and floodplains, to give the river room to swell during floods.

The coalition changed the project from flood control to flood management and hazard mitigation and addressed flood protection and environmental restoration needs throughout the country. The Corps of Engineers with active participation from the Napa County Flood Control and Water Conservation District and the City of Napa prepared a Citizens Guide to explain the project to the layperson. By using the Living River concept, the project is self-mitigating.

This project is the largest and most expensive public works project in Napa County’s history. It is estimated to cost $238 million over 20 years for construction. Ninety Percent of the funding comes from the county sales tax and Federal Government appropriations. Other revenue sources include, amongst others, the FEMA hazard Mitigation Grant Program, the State Revolving Loan Fund and the State Subvention Fund. The completed project is expected to create annual savings of $26million in avoided property damage, according to the Corps of Engineers’ cost benefit formula. These annual savings would be from reduced insurance costs, avoided clean up and emergency service costs and enhanced environmental improvements.

The current completion date for the entire project is 2006.

References:

Napa County Flood Control and Water Conservation District, The Napa Flood Control Protection Project, www.napaflooddistrict.org

U.S. Army Corps of Engineers, Napa River Flood Protection Project, www.spk.usace.army.mil/civ/napa

Uloaku Echebiri

EMSE 232 Class Paper

Napa California Flood Control Project

Traditionally, flood control as a form of mitigation has focused on constraining and controlling a river. These structural controls have always been controversial as a mitigation tool, as they have both positive and negative effects on the areas they are not protecting. They are used to control the hazard and not effectively reduce it. Today, flood control districts, city, county, and environmental groups are seeking new approaches to flood management that combine natural and man-made alternatives. This is essentially the idea behind the Napa River flood protection project. Rather than suffocating the River with concrete contraptions, the project will restore six miles of the River and its watershed. The Napa River project, as well as other ongoing flood control projects in Mississipi, Colorado and Florida, shows that the goal of flood control is being replaced by flood management and hazard mitigation.

Napa City History of Flooding

Napa city was founded in 1847. It is located in the area where the Napa River flattens out into the San Pablo estuary, which is unfortunately susceptible to flooding. The city of Napa has experienced 27 floods between 1862 and 1997, with the most damaging occurring on February 18 1996.

· The 1986 floods occurred as a result of 20 inches of rain falling within a 48 hour period hear Napa at a gauge with an annual rainfall of 36 inches. There were 3 deaths, 2750 homes were destroyed or damaged and 5000 people were made to evacuate their homes.

· In March 1995, the city experiences another flood almost the magnitude of the 1986 floods.

· In January 1997, Napa received 200 percent of the normal rainfall, but there were breaks between the storms, which resulted in minor flooding. However, other cities in California suffered the brunt of the floods (48 California counties were declared federal disaster areas.)

· Between 1961 and 1997, Napa county residents have suffered approximately $542 million in property damage from flooding. Many residential, business, and industrial buildings are located along the Napa River within the city limits.

· The 14 most recent serious floods in the city of Napa occurred in 1942, 1943, 1955, 1962, 1963, 1965, 1967, 1973, 1978, 1982, 1983, 1986, 1995, and 1997.

Project History

· The Federal Government first became involved with the Napa River in 1938, however, no action was taken until a flood protection project was authorized by the Flood Control Act of 1965. There was a prior Flood Control Act of 1944, but it only authorized channel improvements for reaches of the Napa River and Conn Creek as well as the construction of a dam on Conn Creek. However, Government never appropriated construction funds for the project.

In 1975, the Army Corps of Engineers submitted its first flood control proposal to the citizens of Napa County. The citizens rejected it and subsequent proposals because they suggested employing traditional flood control mechanisms of enlarging the existing channel and constraining the river to its main channel levee heights. These measures were seen by the citizens as environmentally insensitive combined with concerns over the degradation of water quality in the river and disposal of contaminated dredge material. Voters opposed the 1975 plan by referendum in 1976 and again in 1997. After its second defeat, the project was placed in inactive status at the request of the Napa County Flood Control and Water Conservation District (NCFCWCD). The NCFCWCD is made up of the County Supervisors and Mayors of Napa, St Helena, American Canyon, Calistoga, and Yountville. They are elected officials and evaluate and vote on recommendations of flood control managers, engineers and analysts.

· In October 1988, the project was reactivated at the request of the NCFCWCD, after public interest in flood damage reduction had been revived due to the devastation experienced from the 1986 flood.

· In April 1995, the Sacramento District submitted a plan to provide 100-year food protection for Napa for public review, but the plan faced the initial criticism and many local and environmental groups requested modifications to the plan.

· To ensure community consensus on a flood protection plan, the NCFCWCD initiated a community coalition, which included the Corps of Engineers, outside consultants and resource agency personnel, to develop the necessary modifications to the plan that would represent the diverse interests of the area. Some of the agencies involved in the plan include the Napa Valley Economic Development Corporation, Sierra Club, Napa Chamber of Commerce, Napa County Land Trust, amongst others.

· The modifications centered on devising a strategy for controlling the floods without “choking the life” out of the river and its tributaries.

· In 1995, the idea of a non-traditional, environmentally-friendly proposal was born.

Project Goals

The 1995 concept developed was one of a “Living River” where the project, as well as protecting the community from flooding, would also allow the river to nourish plant and animal life, while bringing new vitality to neglected riverfront areas. Where the Corps had initially proposed floodwalls and levees, the coalition proposed terraced marshes and broad wetlands, and where proposals for dredging the river deeper to allow it carry muddy water faster, the coalition wanted to make it wider by returning much of its floodplain. If these lands were restored to wetland condition, those areas would be designed to absorb major flood events with little or no harmful effects. Essentially the plan is to ‘let the river be itself.’

The coalition essentially changed the project from flood control to flood management and hazard mitigation and addressed flood protection and environmental restoration needs throughout the country. The Corps of Engineers with active participation from the NCFCWCD and the City of Napa prepared a Citizens Guide to explain the project to the layperson. By using the Living River concept, the project is self-mitigating.

Funding

This project is the largest and most expensive public works project in Napa County’s history. It is estimated to cost $238 million over 20years for construction. NCFCWCD held a local election in 1998 to increase the County sales tax to provide their portion of the financing. Voter polls showed that a 20-yr, a one-half cent tax was achievable and on March 3 1998 Napa County voters approved the tax. The tax initiative ballot was known as ‘Measure A’ or ‘the Living River Initiative.’ The sales tax is expected to raise between 8-10 million USD. People were told that for every $1 spent in flood protection, Napa City residents would receive a projected $7 in savings on property damage. The project also relies on annual appropriations from the Federal Government, however, these appropriations vary according to fiscal conditions. The County sales tax and the Federal government appropriations account for 90% of the project cost estimate.

Other revenue sources include:

· A $7million award in FEMA Hazard Mitigation Grant Program to the city of Napa by the Governor’s Office of Emergency Services. The funds were to be directed towards land acquisition, home elevations and drainage improvements.

· The flood district has also been allocated $35million from the State Revolving Loan Fund and $15million from the State Subvention Fund.

· Funding has also come through grants from the CalFed Bay-Delta Program and Coastal Conservancy; and a Storm Water Service fee adopted by the City Council.

· Other agencies participating in the project include the California Department of Fish and Game, the U.S Fish and Wildlife Service and the San Francisco Regional Water Control Board.

The completed project is expected to create annual savings of $26million in avoided property damage, according to the Corps of Engineers’ cost benefit formula. These annual savings would be from reduced insurance costs, avoided clean up and emergency service costs and enhanced environmental improvements.

Project Progress

· The Third Street Bridge replacement: completed August 2002. The bridge allows for greater water flow on the River during heavy runoff and improves vehicular traffic flow on the river.

· Highway 29/Trancas Street Interchange Project: work began March 2002, with an estimated completion date of December 2004.

· Oxbow Bypass Bridge: began September 2002; estimated completion date January 2004. The project creates a bridge where there is none now in preparation for later excavation to create the River Oxbow Bypass.

· First Street Replacement Bridge: scheduled to begin once the Oxbow Bypass bridge is completed.

· Maxwell Bridge Replacement: work began in April 2003, to be completed at the end of 2005.

These as well as other construction/development projects seem to be on course.

Conclusion

The Napa River project does not rely on a single approach but combines multiple strategies in a way that makes optimal use of engineering, ecology and different funding sources. The project intends to minimize the disruption and alteration of river habitat and maximize environmental restoration and enhancement throughout the wetland. There are many aspects of floodplain management in the project, which includes, among others, emergency planning, bridge replacements, home elevation, wetland creation, setting back levees, and creating a flood bypass. However, no amount of work could guarantee a complete end to the flood threat due to the high unpredictability of the Northern California climate.

The Project is designed to protect the Napa valley from the 100-year flood – an event that has a 1-in-100 chance of occurring in any given year and create a flow in the Napa River more than 30 times the normal flow. The current completion date for the entire project is 2006.

Acronyms

NCFCWCD Napa County Flood Control and Water Conservation District

References

California Environmental Protection Agency, www.swrcb.ca.gov/press/1999/99-04.html, 1999

Congress of the U.S. House of Representatives,

www.swrcb.ca.gov/press/1999/floodcontrol10620

Federal Emergency Management Agency (FEMA) [online], http://fema.gov/regions/

Haddow, George and Bullock, Jane. Introduction to Emergency Management, 2003

Napa County Flood Control and Water Conservation District, The Napa Flood Protection Project, Progress, Plan and Summary 2002, [online] www.napaflooddistrict.org

U.S. Army Corps of Engineers Sacramento District, Napa River Flood Protection Project, www.spk.usace.army.mil/civ/napa

Wadsworth, Graham. Floodplain and Watershed Management in the Napa Valley, www.cityofnapa.org/weather/fmapaper, September 1998

Wheeler, Doug. The Napa River Flood Management Effort, California Biodiversity News, http://ceres.ca.gov/biodiv/newsletter/, Summer 1998