The Town’s floodplain maps have been going through the Federal Emergency Management Agency’s (FEMA) map modernization program. This program updates maps from a paper product to a digital product with aerial imagery as a background, making the maps easier to read and use. During the course of map modernization, FEMA issued “draft” maps of proposed floodplain changes in Marana. These maps considered the Central Arizona Project Canal (CAP), Interstate I-10 and the Union Pacific Railroad (UPRR) to be levee-like structures. Under FEMA’s change in previous policy, they were requiring levee-like structures to be certified in the same manner as actual levees. Essentially, these structures were not constructed as levees, do not meet the levee requirements, and the owners of these facilities do not maintain them as levees.
As a result, FEMA’s draft maps would bring large areas of Marana into an indeterminate Special Flood Hazard Area (SFHA) – including significant areas that had been previously removed from the SFHA by letters of map revision. The affected land included everything between the Santa Cruz River and either the CAP canal or the UPRR from the county line to Ina Road. It is important to note that FEMA had identified these areas as being at risk in the absence of actual study and that the indeterminate nature of their SFHA designation gave no details on the depth of flooding. The Town of Marana disputed this simplified approach by FEMA and with backing from our congressional leaders, map modernization was put on hold in Pima County so that the Town could conduct a large scale detailed floodplain study of the Tortolita Mountain alluvial fan and assess the levee-like structures. Also at that time FEMA reversed their policy on levee-like structures having to be treated as levees. FEMA now allows analysis of levee-like structures on a case by case basis to determine their effectiveness in affecting floodwaters. The Marana study has helped shape the parameters of how this analysis is performed.
The Town of Marana selected CMG Drainage to perform this large scale drainage study to show the actual floodplain hazards of the entire Tortolita Fan and assess the levee-like structures in the Town limits. FEMA gave the Town until October 1, 2008 to submit the study information. CMG Drainage completed the study and submitted it to FEMA in August 2008. CMG’s study verified some of the areas FEMA identified as SFHA, but the majority of the original affected area was shown in the Town’s study to not meet the classification of Special Flood Hazard Area. Areas that are not classified as SFHA can and do flood. Flood insurance can be purchased in areas that are not classified as SFHA for more reasonable rates than those that are classified as SFHA. Homeowners may contact their home insurance providers (most of which can broker FEMA flood insurance policies) regarding a “preferred risk policy” for more information.
The final review by FEMA was completed and the CMG study was formally accepted by FEMA on March 30, 2009. With this acceptance, FEMA’s map modernization program has restarted. As part of the disclosure of study required by FEMA to issue a new Flood Insurance Rate Map (FIRM), the Town is providing on this webpage the workmaps from the CMG study. The workmaps are of a reduced file size to facilitate downloading but are legible for flow depths. Workmaps in their original resolution and file size are available from the Town as is the CMG drainage study. An appeal period soliciting technical information and comments started October 16, 2009 and ends January 13, 2010. Once the appeal period is completed for the new FIRM, the Town will provide recommendations for those residents who will be brought into the SFHA on how to mitigate their situation by way of grandfathering flood insurance policies. The Town of Marana intends to perform additional study for areas of the Town that are confirmed to be SFHA as a result of our study. Additional studies would include the design of flood protection infrastructure and the subsequent modification of the SFHA mapping through FEMA’s letter of map revision process. This is a much longer process that will take several years.
The Town of Marana’s floodplain management staff will answer questions as we are able at (520) 382-2600. Town of Marana staff cannot give insurance rate quotes.
Viewing your property using GIS
One of the distinct advantages of the new maps is that the digital information has been given to the local jurisdictions to add to our GIS databases. With this information, we can utilize even newer aerial photography than the published maps and also zoom in on the maps with a property ownership parcel database for better clarity. Pima County Regional Flood Control District has created a web based GIS application that allows one to view a property with a side by side comparison between current floodplain status and floodplain status after the new maps become effective. This application works for all jurisdictions in Pima County but please note that if you live within Marana town limits the application will refer you back to Marana for information. The application can be accessed using the following link:
http://www.rfcd.pima.gov/dfirm
Filing an appeal or protest to the maps
Please review the following document on the technical requirements to file an appeal or protest. All appeals or protests should be submitted to the Town of Marana Engineering Department, 11555 W. Civic Center Drive, Marana, AZ 85653.
FEMA Guideline on Appeals and Protests
Work maps from CMG Engineering Drainage Study
Below are the work maps from the CMG drainage study. The CMG study utilized Flo-2D software which processed the flow patterns in a grid format. The grid spacing was 100 feet by 100 feet. The numbers on the work maps correspond to the water depth for each respective 100 foot square formed by the grid. These work maps form the basis of floodplains depicted on the 2009 preliminary Flood Insurance Rate Maps (FIRM) for the Tortolita Fan area only. Other areas of Marana were updated with letters of map revision since 1999 but were not restudied.
CMG Workmap Index
CMG Workmap 1
CMG Workmap 2
CMG Workmap 3
CMG Workmap 4
CMG Workmap 5
CMG Workmap 6
CMG Workmap 7
CMG Workmap 8
CMG Workmap 9
CMG Workmap 10
CMG Workmap 11
CMG Workmap 12
CMG Workmap 13
CMG Workmap 14
CMG Workmap 15
CMG Workmap 16
CMG Workmap 17
CMG Workmap 18
CMG Workmap 19
CMG Workmap 20
2009 Preliminary Flood Insurance Rate Maps
As part of the publishing requirements for the 2009 preliminary Flood Insurance Rate Maps, FEMA and the Town of Marana are presenting the 2009 preliminary FIRM panels here. Paper copies of these FIRM panels may be viewed at the Town of Marana Engineering department at the Marana Municipal Complex. At the conclusion of the appeal period and resolution of any changes due to appeals, the maps will be re-published as a final FIRM with an effective date sometime in late summer of 2010.
2009 FIRM panel index
Panel 04019C0415L
Panel 04019C0420L
Panel 04019C0440L
Panel 04019C0445L
Panel 04019C1010L
Panel 04019C1020L
Panel 04019C1030L
Panel 04019C1035L
Panel 04019C1040L
Panel 04019C1045L
Panel 04019C1055L
Panel 04019C1060L
Panel 04019C1065L
Panel 04019C1070L
Panel 04019C1650L
Panel 04019C1655L
Panel 04019C1660L
Panel 04019C1665L
Panel 04019C1666L
Additional infomation can be found at the following web sites:
FEMA
FLOODSMART.GOV
National Flood Insurance Program Grandfather Rules
Town of Marana Flood Plain And Erosion Hazard Management Code
