Public Notice: DR-4836-AK Embankment Armoring Project

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The City and Borough of Juneau has applied for Federal Emergency Management Agency (FEMA) Public Assistance (PA) grant funding under Presidentially declared disaster DR-4836-AK through the Alaska Division of Homeland Security and Emergency Management.  Per 44 CFR Part 9, Presidential Executive Orders 11988 and 11990, FEMA gives early public notice.  Federal agencies are required to avoid, to the extent possible, the short- and long-term adverse impacts associated with the occupancy and modification of floodplains and wetlands and to consider practicable alternatives to the proposed project and provide public notice. Funding for the proposed projects will be conditional upon compliance with all applicable federal, Tribal, state, and local laws, regulations, floodplain standards, permit requirements and conditions.

Embankment Armoring Project Locations:

Antler Way, GPS: 58.362500, -134.597000 to 58.362700, -134.596800

Wastewater Treatment Plant, GPS: 58.362167, -134.597611 to 58.361611, ‑134.598083

Rivercourt Way, GPS: 58.381011, -134.594094 to 58.380924, -134.594196

Floodplain and Wetland Determination: All embankments are located within the Zone AE floodplain and regulatory floodway as mapped by Flood Insurance Rate Map Panel Numbers: 02110C1238E and 02110C1526E, both effective 9/18/2020. Embankments are located within riverine wetlands, as mapped by the US Fish and Wildlife’s National Wetlands Inventory Mapper.

Proposed Work and Purpose: City and Borough of Juneau is requesting funds to repair eroded embankment armoring along the Mendenhall River back to its pre-disaster design, capacity, and function within the existing footprint. Work at each location will include:

• Antler Way: Replacing approximately 490 CY of class III rip rap and 120 CY of 10-inch minus diameter shot rock, in an area measuring 60 feet long and 55 feet deep.
• Wastewater Treatment Plant: Replacing approximately 1,800 CY of class III rip rap and 440 CY of 10-inch minus diameter shot rock, in an area measuring 200 feet long and 60 feet deep.
• Rivercourt Way: Replacing approximately 410 CY of class III rip rap and 100 CY of 10-inch minus diameter shot rock, in an area measuring 77 feet long and 36 feet deep.

Project Alternatives Considered: 

 Alternative #1 (Mitigation Alternative): This alternative would have provided funding for additional rock armoring and/or metal sheet piling along each embankment. This would have increased the resilience of the armoring devices to heavier flood flows, but would also increase artificial hardening in floodplains and wetlands. Developing engineering designs for this alternative would require substantial time and could not be completed before the next flooding season begins. This seasonal flooding threatens further erosion along the embankments. Due to these time constraints this alternative was not selected.

Alternative #2 (Bio-engineering Alternative): This alternative would have added nature-based solutions, such as root wads or vegetative cover over armoring rock, to improve aquatic habitat and mitigate artificial improvements to the river. This alternative was not selected as it was determined to be structurally unsound due to high flood velocities in the Mendenhall River.

Alternative #3 (No Action Alternative): The no action alternative would have left the damaged embankments in their current, damaged condition. This action was not selected due to the risk to essential public (wastewater treatment plant) and residential infrastructure. The necessity for this protection at these locations outweighs the impacts to floodplains and wetlands.

Comment Period: This notice will serve as the final public notice regarding the above-described actions funded by FEMA PA. Interested persons may submit comments, obtain more detailed information about the proposed action, or request a copy of the findings by contacting:

Comments should be sent to the above addresses within 15 days of the date of this notice. Please remove after 15 days after posting.