Project elements

Overview

The United States Senate passed legislation for more than $212 million in federal funding for the Ala Wai Canal Project. The Ala Wai Canal Project is a flood mitigation project created by the USACE. Read on to see what this project includes and the impact it will have on Oahu's land and residents. 

Project Elements

• Concrete wall around Ala Wai Canal

• Embankment around Ala Wai golf course

• 7 large detention basins near residential areas

of concern

Appendix E: page 748

Concrete Wall Around Ala Wai Canal

Appendix E: page 549

Appendix E: page 549

Dimensions: 4ft. high concrete wall along the Ala Wai Canal, projected to be 1.9 miles long

Objective: Prevent the canal from overflowing into Waikiki

(When was the last time you saw the canal massively overflow?)

Earth Embankment Around Ala Wai Golf Course

Appendix E: page 625

Appendix E: page 550

Dimensions: 4 ft. high man-made earth embankment around the Ala Wai Golf Course

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Objective: Golf course turns into a detention basin to prevent floodwaters from flowing into Waikiki

Detention Basins

1) Kanewai Field Detention Basin

2) Woodlawn (Manoa Valley): on private property that will be seized

3) Waihi (Manoa Valley)

4) Waiakeakua (Manoa Valley)

5) Pukele Detention Basin: 13 private properties will be seized from families

6) Waiomao Detention Basin: 6 private properties will be seized from families

7) Makiki Detention Basin

Kanewai Field Detention Basin

Read letters that call for the reconsideration of the Ala Wai Canal Project.

Location: Encompasses all of Kanewai Field located above Hokulani Elementary School

Objective: Use existing open space to temporarily contain floodwaters

Details:

• Maximum volume: 900,000 cubic feet (a football field filled 16 feet high with water)

• Stormwater will be detained by a man-made 9-ft tall earth embankment 

• Poses risk to residents downstream should basin ever overtop or fail

• Negatively affects the park’s use by the community and Hokulani Elementary school

• Becomes a safety hazard to children and pets when basin is filled

As seen on: Manoa Technical Summary Final

Woodlawn Ditch Detention Basin (Manoa Valley)

Appendix I: page 54​

As seen on: Manoa Technical Summary Final

Location: Just below the Chinese Cemetery in Manoa Valley on farmland bounded by East Manoa Road, Kolomona Road, and Lower Place. The structure does not interfere with the houses off of Kolomona Road, but does encompass the farmland below the cemetery. Spans over Woodlawn Ditch. 

Objective: Control the flow into the Woodlawn-Manoa confluence and divert floodwater further downstream. This design assumes that slightly less than 750cfs is a safe flow rate for Woodlawn Ditch and that the diverted water will not have an adverse effect on flows downstream. It also assumes that with the 100-year flood, all water can be contained within the basin and there will be no need to use the emergency spillway unless these floodwater rates are exceeded.

Details:

• Stormwater will be detained by a man-made structure 20-ft high  

• Poses risk to residents below should basin ever overtop or fail 

• A safety hazard to children and pets when filled

Waiakeakua Detention Basin (Manoa Valley)

Waihi Detention Basin (Manoa Valley)

Appendix I: page 12

Pukele Detention Basin (Palolo Valley)

Appendix I: page 20​

Waiomao Detention Basin (Palolo Valley)

Appendix I: page 16​

Makiki Debris Detention Basin

Objective: Designed to hold over 8.7 million gallons of stormwater (the equivalent of a football field filled 20 ft. high with water

Details:

• Structure will be186 ft. thick, 100 ft. wide, and over 33 ft tall. 

• Public charter school, Halau Ku Mana is located on TMK 25020004 (see above)

• Earth embankments will affect views of residents and those who travel on Round Top Dr and Makiki Heights Dr.

• Will destroy approximately 800ft of natural stream and acres of land

• Pose risk to residents downstream should basin ever overtop or fail

• Safety hazard to children and pets when filled

• Man-made eyesore