BALBOA ISLANDS SEAWALL REPLACEMENT PROJECT Balboa Island Improvement

BALBOA ISLANDS SEAWALL REPLACEMENT PROJECT Balboa Island Improvement Association Beek Center May 22, 2014

Tonight’s Agenda 1. Brief background review 2. Primary Topic: Top of seawall elevation for both Islands § Option 1: Seawall Top at 10. 0 feet (both Islands) § Option 2: Seawall Top at 9. 5 feet (both Islands) § Option 3: Variable Top Elevation (9. 0/9. 5 feet) (Elevation Datum: NAVD 88 )

Background Aging 75 - to 85 -year old seawalls are at the end of their useful lifetime.

Seawall Overtopping The low-lying Balboa Islands need protection from rising tides, storm surges and wind waves.

Substandard Freeboard West end of Balboa Island during a king tide on December 12, 2013 with no storm surges or wind waves.

Projected Sea Level Rise – 2100 �Mean sea level rise is expected to be in the range of 24 -36 inches. �California State Coastal Conservancy (SCC) in 2009 adopts a Climate Change Policy that agencies should prepare for a 55 -inch sea level rise by 2100. (high confidence)

Summary of Previous Discussions Direction Un. Provided decided New wall built on waterside Steel H-piles w/ concrete planks Width of top cap ~24 inches Maintain existing boardwalk elevation How will new seawalls be paid for? X X X Top of wall elevation: a) Longer Range Protection: 9. 5’ or 10. 0’ b) Lower Initial Cost: 9. 0’/9. 5’ Elevation Datum: NAVD 88 (Example: 10. 00 feet NAVD 88 = 10. 18 feet MLLW) X X

PROPOSED “H” PILE SYSTEM WITH CONCRETE PLANKS (Elevation Datum: NAVD 88 )

Balboa Islands Seawall Website http: //www. newportbeachca. gov/seawalls

Typical Top of Seawall Elevations at Other Locations � County of Orange (Dana Point): 9. 62’ � County of LA (Marina del Rey): 9. 62’ - 11. 62’ � City of Huntington Beach (General): 9. 62’ � City of Long Beach (Alamitos Bay): 9. 62’ � City of Long Beach (Naples Island): 9. 50’ (planned) (Elevation Datum: NAVD 88 )

New Top of Wall Elevation. Option 1: 10. 0 feet (NAVD 88)

New Seawall Top Elevations: Option 1 a. Raise cap on the north side of Balboa Island to 10. 0’ and new seawalls to 10. 0’ around the remaining portions of both Islands. b. As needed, replace the capped seawall on the north side of Balboa Island with a new seawall. (Elevation Datum: NAVD 88 )

New Top of Wall Elevation. Option 2: 9. 5 feet (NAVD 88)

New Seawall Top Elevations: Option 2 a. Raise cap on the north side of Balboa Island to 9. 5’ and new seawalls to 9. 5’ around the remaining portions of both Islands. b. As needed, in possibly 40 years, add extensions to the new seawalls and replace the capped seawall on the north side of Balboa Island with a new seawall. (Elevation Datum: NAVD 88 )

Options 1 & 2: Longer Range Protection �Option 1 Flood Protection (10. 0’): ~2063 �Option 2 Flood Protection (9. 5’): ~2056 Estimated cost: 25% contingency: Total: $56 million 14 million $70 million Notes: 1. Costs includes seawalls, caps, pier and beach access ramps, modifications to the entrance to the Ferry Landing and Collins Islands, and ADA modifications to the Boardwalk near the Mariner’s Bridge. 2. Seawall cost are based on 2014 bids for the new seawalls in Naples, Long Beach. 3. Costs in today’s dollars 4. Elevation Datum: NAVD 88

PRIVATE PIER ACCESS

OPTION 3: VARIABLE TOP ELEVATION

New Seawall Top Elevations: Options 3 New seawalls on West End (9. 5’) and Grand Canal (9. 0’north/9. 5’south). b. Raise seawall cap on south side of Islands to 9. 5’ c. Raise seawall cap on north side of Islands to 9. 0’ d. As needed, in possibly 30 years, extend new seawalls to 10. 0’+ and replace capped seawalls with new seawalls. a. (Elevation Datum: NAVD 88 )

Option 3: Lower Initial Cost �Option 3 Flood Protection: ~ 2047 Concept level cost: 25% contingency: Project total: $27 million $34 million Notes: 1. Costs includes seawalls, caps, temporary pier and beach access ramps, modifications to the entrance to the Ferry Landing and Collins Islands, and ADA modifications to the Boardwalk near the Mariner’s Bridge. 2. Seawall cost are based on 2014 bids for the new seawalls in Naples, Long Beach. Costs in today’s dollars 4. Elevation Datum: NAVD 88 3.

Top Elevations Options Summary Table Option 1 (10. 0’) Option 2 (9. 5’) Option 3 (9’/9. 5’) Year ~2020: Initial construction cost (w/ 25% $70 million contingency) $34 million Projected flood protection until based on California SCC Climate Change Policy: 2063 2056 2047 Year ~2045: Option 3 - Stage 2 construction cost (w/ 25% contingency) to build remaining seawalls and extend caps to minimum Elevation 10’. $57 million Year ~2054: Option 2 - Stage 2 construction cost (w/ 25% contingency) to build remaining seawalls and extend caps to minimum Elevation 10’. $19 million Year ~2060: Option 1 - Stage 2 construction cost (w/ $16 million 25% contingency) to build remaining seawalls. (Elevation Datum: NAVD 88 )

Project Signs (concept) to be located on alternate lightpoles around the Balboa Islands. 10. 0’ NAVD 88 (10. 18’ MLLW) 9. 5’ NAVD 88 (9. 68’ MLLW) Proposed Top Elevation of New Seawalls The lines on this sign illustrate options for the top elevation of a new seawall that would be constructed just outside the existing sea wall in order to provide current and future flood protection. For more information visit: http: //newportbeachca. gov/

Next Steps 1. 2. Look for Story Boards Log onto the City Webpage: http: //www. newportbeachca. gov/seawalls 3. Email your comments and concerns to: seawalls@newportbeachca. gov Determine preferred direction for top of seawall elevation. 5. Complete construction documents and obtain permits. 4.

Sea Level Rise Predictions – 2100 The “ 95%” column on the right side of the table indicates there is a 5% chance the predicted sea level rise will be exceeded. Agency Year 5% 50% 95% (high confidence) IPCC 4 th Assessment 2007 9” 15” 20” Vermeer and Rahmstorf 2009 39” 49” 61” US Corps of Engineers 2011 17” 39” 59” National Academy of Sciences 2012 17” 37” 66” IPCC 5 th Assessment 2013 17” 24” 31” Quaternary Science Reviews 2014 28” 37” 47” California State Coastal Conservancy in 2009 adopts Climate Change Policy of 55 -inch sea level rise by 2100.

PRIVATE PIER ACCESS

PUBLIC PIER AND BEACH ACCESS

BEACH ACCESS CONCEPT