Flood Management

Flood Management: General Plan Amendment and Zoning Regulations

California Senate Bill (SB) 5 (Machado) requires the City to amend its General Plan and Zoning regulations to address flooding that has a 1-in-200 chance of occurring in any given year (i.e., a 200-year storm). Specifically, the General Plan Amendments are to include:

  • data and analysis contained in that flood protection plan; 
  • goals and policies for the protection of lives and property that will reduce the risk of flood damage; and
  • feasible implementation measures. 
    The Zoning regulations are to implement these goals and policies on any new development that may occur within the 200-year floodplain. Regulations to address a 100-year storm (i.e. 1-in-100 chance of occurring in any given year) were also updated with a new Flood Damage Prevention Ordinance to improve protections and provide greater clarity.

The City has drafted the necessary revisions to the General Plan and Zoning to implement SB 5.  The draft materials are available for review at the links below and are summarized below.  A Frequently Asked Questions is also provided.

The Zoning regulations are to implement these goals and policies on any new development that may occur within the 200-year floodplain. Regulations to address a 100-year storm (i.e. 1-in-100 chance of occurring in any given year) were also updated with a new Flood Damage Prevention Ordinance to improve protections and provide greater clarity.

The City has drafted the necessary revisions to the General Plan and Zoning to implement SB 5.  The draft materials are available for review at the links below and are summarized below.  A Frequently Asked Questions is also provided.

The Zoning regulations are to implement these goals and policies on any new development that may occur within the 200-year floodplain. Regulations to address a 100-year storm (i.e. 1-in-100 chance of occurring in any given year) were also updated with a new Flood Damage Prevention Ordinance to improve protections and provide greater clarity.

The City has drafted the necessary revisions to the General Plan and Zoning to implement SB 5. The draft materials are available for review at the links below and are summarized below.  A Frequently Asked Questions is also provided.

Draft 100-year floodplain map
Draft 200-year floodplain map

City Staff Contact

Amittoj Thandi 
8401 Laguna Palms Way 
Elk Grove, CA 95758 
(916) 478-2252
athandi@elkgrovecity.org

Summary of Proposed Changes

General Plan: Safety Element Zoning Flood Damage Prevention Ordinance

Amends the General Plan’s Safety Element to:

  • Adds maps illustrating the existing 100-year and 200-year floodplain.

  • Adds a policy, as required by SB 5, calling for new City and healthcare facilities to be located outside the 100-year and 200-year floodplains.

  • Adds a policy, as required by SB 5, prohibiting the City from approving a development project, development agreement, or building permit for a project located outside of an area with an Urban Level of Flood Protection (the 200-year floodplain) unless certain findings are made.













Amends Chapter 23.42.040 of the City’s Municipal Code, Flood Combining District, to:

  • Differentiates between the 100-year and 200-year floodplain, and areas where the 100 and 200-year floodplain overlap.

  • Connects development in the 100-year floodplain with construction requirements in the new Chapter 16.50 (Flood Damage Prevention).

  • Establishes the findings required for development in the 200-year floodplain as directed by the General Plan amendments.  Note, development in areas with flood depths less than 3 feet are exempt from the finding requirement, as allowed under SB 5.

To assist in understanding how proposed projects will be analyzed and are subject to the findings and standards, staff has developed this analysis flowchart.











Added a new Chapter 16.50 of the City’s Municipal Code that:

  • Establishes the process for managing the 100-year floodplain as required under the National Flood Insurance Program (NFIP).

  • Establishes a permit requirement for development within the 100-year floodplain.  The permit is either approved at a staff level as part of a building permit application, or at the time of subdivision approval.

  • Prohibits most types of structures from being constructed within the 100-year floodplain, consistent with existing General Plan policy, unless certain improvements are approved by the City.

  • For structures that are allowed in the floodplain (detached garages and other non-habitable structures), it establishes design and development standards for new construction that is within the 100-year floodplain.






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What is the purpose of this project? Why is the City looking at the 200-year floodplain?

SB 5, the flood management legislation enacted by the state in 2007, requires that local governments develop maps relating to 200-year flood events and establish policies to address potential flood risk, consistent with the Central Valley Flood Protection Plan. This was prompted by numerous studies which show that the San Joaquin Delta and portions of the Central Valley would be highly vulnerable in the case of a large magnitude flood event. The City used data collected from several engineering models to get the most accurate and up-to-date data for potential flood risk in Elk Grove in the case of an event of this magnitude.

How likely is a flood of this magnitude?

The flood maps represent the area at risk during a “200-year flood”—that is, an event of such magnitude that it has a 1 in 200 chance of occurring in any given year. It does not mean an event that occurs every 200 years.

What would cause a flood like this?

Major flood events, such as the 200-year flood event, are typically caused by rare atmospheric conditions that direct a persistent flow of moisture-laden air over an area, colloquially called the “Pineapple Express.” The heavy precipitation from such events can produce large amounts of runoff that can exceed the capacity of local creeks, rivers, and flood control systems. Our region’s flood systems historically have not been designed to manage a 200-year flood event. However, regional projects are being planned, designed, and constructed to reduce or eliminate flooding during such a flood event.

Will I need flood insurance? Will I need a higher level of flood insurance? What does this mean for my home?

No. Currently, FEMA requires flood insurance for properties within the 100-year flood areas but not for properties that lie within a 200-year flood area. There is no immediate impact to existing homes because of this new information. Rather, the City, in partnership with other agencies such as the Sacramento Area Flood Control Agency and Central Valley Flood Protection Board, will work to address potential flood impacts before they occur. Improvements may include raising or reinforcing levees, improving drainage facilities, or hardening critical infrastructure.

What is the local flood control system in Elk Grove designed to withstand?

In which case the response in that per the City’s current Design Standards all pipe systems are required to accommodate at least the 10-year storm event flows and open channel systems are designed to accommodate 100-year flows with at least 1-ft of freeboard. The City’s current Design Standards require all new flood structures must be protected from at least the 100-year storm event (i.e. a magnitude event..

How accurate is this map?

The flood map was prepared using the best available information and state-of-the-art engineering tools. Development of the flood maps required a number of assumptions and estimates of how the local flood control system will respond during a large storm event. Because of this, the maps should be considered an estimate of the potential flood risk, rather than an exact representation of what will happen during a 200-year flood event.

I’m interested in developing property that is shown to be at risk to flooding. What does this mean for me?

Applicants for parcels located within the 200-year flood zone, as shown in the Safety Element, will have to assess whether the proposed project has adequate flood protection. This assessment is required by the Central Valley Flood Protection Plan and Elk Grove General Plan. The City of Elk Grove Planning Department staff will help applicants determine this during development review. Depending on the risk, certain properties may require additional protections installed or new construction may not be allowed.

What is the City doing to address the flood risk?

This mapping assessment and new policies in the Safety Element are the first steps the City is taking to provide greater flood protection for the community. The City is also working with other jurisdictions in the region, including the Sacramento Area Flood Control Agency and Central Valley Flood Protection Board, to plan and build better infrastructure to protect against flooding.

What can I do to protect my home and family from flooding?

You can learn about how to protect your family and property in the case of a flood at:http://www.elkgrovecity.org/city_hall/departments_divisions/public_works/drainage/flood_preparedness

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