Stormwater and Floodplain Management

The City of Maricopa is one of more than 22,000 communities nationwide that participate in the National Flood Insurance Program (NFIP). As an NFIP participant, Maricopa is required to adopt and enforce a floodplain management ordinance to help reduce future flood damage. In exchange, the NFIP makes federally backed flood insurance available to homeowners, renters, and business owners within the City.

Within participating NFIP communities, the Federal Emergency Management Agency (FEMA ) is responsible for determining the extent to which flooding might threaten any given area of land. Flooding threat classifications run from minimal to severe, with severe areas categorized as "Special Flood Hazard Areas" (SFHAs).

Also known as the 100-year floodplain, SFHAs are defined as the area associated with a flood that has a 1 percent annual chance of being equaled or exceeded in any given year. Therefore, the SFHA is not a flood that happens once in a hundred years; rather, it’s a flood that has a 1 percent chance of occurring every year. Thus, a 100-year flood could occur more than once in a relatively short period of time. Statistically, structures located in SFHAs have a 26 percent chance of being flooded over the course of a 30-year mortgage.

Any development that is proposed within a floodplain requires a Floodplain Use Permit before construction can begin. The City reviews plans and proposals for development to ensure that the project meets the minimum requirements of the National Flood Insurance Program (NFIP) and the City’s Floodplain Ordinance. In addition to this, the Floodplain Use Permit process helps to ensure that a development project will not have an adverse impact to the floodplain or to adjacent properties.

For Commercial and Industrial projects as well as Subdivisions, the Floodplain Use Permitting process is included as a step within the Community Development Department's Site Plan Review or Subdivision Review and Platting process.

For single-lot residential development such as new homes or accessory buildings, a Floodplain Use Permit must be applied for separately from a Building Permit. Due to the requirements that may be imposed on your proposed structure (such as elevating the building to one foot above the base flood elevation), it is highly recommended that you wait to apply for a Floodplain Use Permit until after you have applied for a Building Permit.

Maricopa is impacted by three primary watercourses. The Santa Cruz, Santa Rosa, and Vekol washes all flow through the City. There are other sources of flooding as well and it is important to note that you do not need to live near water to be flooded!

Maricopa has a long history of flooding with significant events in 1941, 1952, 1957, 1962, 1983, and 1992. The 1983 flood is considered the record flood and was the result of the remnants of Tropical Storm Octave. While many improvements have been made to mitigate the risk of flooding, the potential for flooding in the area is very real.

To obtain secured financing to buy, build or improve structures located in SFHAs, owners are required to purchase flood insurance. Federally regulated lenders are required by law to determine whether the structure is located in a SFHA and must provide the buyer with written notice that flood insurance will be required. In other words, properties located in SFHAs and do not have flood insurance will not be granted a loan.

Typical homeowner's insurance policies do not include flood protection, instead it has to be purchased separately. And because the City participates in the NFIP, you can purchase flood insurance whether you are in a floodplain or not.

Everyone lives in a flood zone whether you live in a low-, moderate- or high-risk flood area. You do not need to live near water to be flooded. Floods are generally caused by seasonal storms but in some cases, extreme weather events like tropical storms and hurricanes can make their way into Arizona. But flooding can also be caused by water backup due to inadequate or overloaded drainage systems, as well as broken water mains.

Prior to purchasing a property, refinancing for a new bank loan, or applying for a permit to build a new home or structure, it is wise to inquire whether or not you are "in a floodplain". The basis for that determination is provided on the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps or FIRMS. The FIRMS are designed to show the "100-year floodplains" and were originally used for flood insurance purposes. Now, they are the principal tool to provide the best available flood risk information.

To see the local floodplains, use one of the following links.

FEMA Flood Map Service Center

• Use the address locator and other tools to navigate to the location in which you are interested.
• For more robust viewing and printing capabilities, click on the "Go To NFHL Viewer" tab.

Pinal County Map Viewer

• Use the tools to navigate to the property in which you are interested.
• Search for an address or parcel number by clicking on the "Search" menu located on the left side of the map.
• You can turn on the flood zone information by going over to the "Layers" menu and clicking on the "Flood Zones" and "Administrative Floodplains" layers after the property has been selected.
• Keep in mind that sometimes there are map revisions that aren't shown on these maps.

The Pinal County Flood Control District operates and maintains a network of real-time sensors used to collect hydrometeorological data. This network provides information to county personnel and other agencies about precipitation, stormwater runoff, and weather conditions affecting our regional watersheds. Using radio telemetry, sensors report data in the National Weather Service Automated Local Evaluation in Real Time (ALERT) format. This type of network is commonly referred to as an ALERT system. ALERT system sensors are event-driven and transmit data in real-time to base station computers.

Event-driven real-time transmission means that transmission of data occurs immediately as data is collected at field sites. Data collected by the ALERT system is used by the National Weather Service to assist in issuing flood watches and warnings and to ground-truth radar-determined rainfall estimates.

• ALERT reporting page