Alaska Risk MAP Program

Community Risk MAP Studies

Matanuska-Susitna Borough

FEMA and the State of Alaska are conducting a Risk MAP Study in the Matanuska-Susitna Borough that began in 2013.

Matanuska-Susitna Borough Risk MAP Discovery Documents
Matanuska-Susitna Borough Risk MAP Coastal Study Documents

Study Scope

The scope of work of the Matanuska-Susitna Borough Risk MAP Study includes (see also the map below):

Detailed hydrology and hydraulic modeling to include 71.9 miles of riverine study, perform approximate riverine analysis for 316.6 miles, and delineate 15.4 miles of existing areas. Floodplain boundaries will be updated for the 1-percent and 0.2-percent-annual-chance (100- and 500-year) flood events. The rivers to be updated include:

  • Updated detailed modeling (Zone AE) will be completed for:
    • Little Susitna River (including Split Flows 1-3) = 39.2 mile
    • Willow Creek = 13.3 miles
    • Willow Creek Tributary = 7.1 miles
  • Limited detail modeling (Zone A with structures) will be completed for:
    • Wasilla Creek = 10.7 miles
  • Updated Approximate Studies (Zone A) will be completed for:
    • Upper Matanuska River = 14 miles
    • Point MacKenzie = 2 miles – roughly from Walsop Road to 2 miles downstream of Walsop Road
    • Various Zone A = 289.9 miles
  • Redelineation of Effective Detailed Studies (Zone AE) will be completed for:
    • Deception Creek and Tributaries 1-3 = 15.4 miles
  • US Army Corps of Engineers (USACE) Studies (Leverage - Zone AE) will also be incorporated to include:
    • Matanuska River = 3.9 miles
    • Knik River = 2.7 miles
    • Bodenburg Creek = 5.7 miles
  • Preparation of a regulatory Flood Insurance Study (FIS) Report document to the Community. A FIS is a book that contains information regarding flooding in a community and is developed in conjunction with the FIRM. The FIS, also known as a flood elevation study, frequently contains a narrative of the flood history of a community and discusses the engineering methods used to develop the FIRM. The study also contains flood profiles for studied flooding sources and can be used to determine Base Flood Elevations for some areas.
  • Preparation of a regulatory Flood Insurance Rate Map (FIRM) map for all panels within the Community which identifies the Community's flood zones, base flood elevations, and floodplain boundaries. This map is used to determine where the purchase of flood insurance is required for properties with federally-backed mortgages. The preliminary FIS and DFIRM’s are scheduled to be released in September 2015.
  • Collect LiDAR in Summer 2015. This data will be delivered to the community by Fall 2015.
  • All of the above datasets will be in the in the North American Vertical Datum of 1988.
  • The State and FEMA will provide guidance, feedback, coordination and technical support throughout the Risk MAP Project Life Cycle.


Project Status

The project is currently in the production stage. The following table illustrates project status and includes major milestones with dates:

Activity Actual or Projected End Date
Discovery Interview March 11, 2013
Discovery Meeting April 23, 2013
Engineering Analysis Summer 2105*
Draft Work Maps Issued Summer 2015*
Flood Risk Review Meeting Summer 2015*
Preliminary Map Production September 2015*
Final CCO & Public Meeting September 2015*
Non-Regulatory Products (Flood Risk Report, Flood Risk Database, and Flood Risk Report) Fall/Winter 2015*
Resiliency Meeting November 2015*
Effective Map Production Summer/Fall 2016*
*All projected dates are subject to revision as the project progresses


Map of Matanuska-Susitna Borough Study Scope

Matanuska-Susitna Scope Map



Matanuska-Susitna Borough Discovery
(FEMA Region X Workspace)
  Matanuska-Susitna Borough
PIN Website
  FEMA Region X
Risk MAP Newsletters

For more information contact:

Sally Russell Cox

State of Alaska Risk MAP Coordinator
Division of Community and Regional Affairs
Department of Commerce, Community, and Economic Development
550 West 7th Avenue, Suite 1640, Anchorage, AK 99501-3569
Phone (907) 269-4588 Fax (907)269-4539