A revised plan to have a private developer renovate and expand the Kewalo Basin small-boat harbor in Kakaako received its last major approval after about a decade of work.

The Hawaii Community Development Authority, a state agency that owns the run-down harbor mostly used by commercial tour and charter operators along with some personal yacht owners, approved the plan by Howard Hughes Corp. on Wednesday in a 6-2 vote by board members. HCDA directors Steve Scott and Mary Pat Waterhouse voted no.

The work will be done in phases so that harbor users aren’t displaced, according to Hughes Corp., which already manages the harbor under a lease with HCDA and contracts out daily operations to Almar Management. Work is expected to begin late this year or early next year, and take three years to finish.

The $20 million project would add a fuel dock and 70 slips to the 144-slip facility, replace docks and improve water, sewage and electrical systems. Security cameras, LED lighting and a new Wi-Fi system are also part of the plan.

The board raised some concerns about the fuel dock, including whether it would be a hazard in a tsunami and whether Hughes Corp. added it to boost income from harbor operations. Hughes Corp. said the fuel facility would be safe and was added as a service for tenants. HCDA had included a fuel station in an earlier harbor improvement plan.

Concerns over the fuel dock delayed the board from voting at meetings in June and July.

Todd Apo, vice president of community development for Hughes Corp., said the company appreciates the board’s approval.

“There is much needed work for safety, security, and overall improvement to the piers and infrastructure at Kewalo Harbor that this approval will allow us to undertake,” he said in a statement. “As we move forward, we are excited to bring these upgrades to the community, creating an exceptional experience for Kewalo Harbor businesses and visitors.”

Besides improvements to the harbor, Hughes Corp. has a separate plan approved by HCDA to open a convenience store with outdoor seating and an events pavilion with surfboard lockers in two old buildings at opposite ends of the harbor.

This separate plan also will include 102 metered parking stalls and space for lifeguard operations. This plan is estimated to cost $6 million and was approved by HCDA in December.

Hughes Corp. envisions the harbor, which long ago was a base for commercial aku fishermen, as an attractive accompaniment to the 60 acres mauka of the harbor that the company owns and is slowly transforming into Ward Village, a community with up to 22 condominium towers and more than 1 million square feet of retail.

Kewalo Basin began as a wharf in 1920, and in 1929 attracted commercial fishing operations anchored by wooden sampan boats. In more recent decades charter and tour boat operators grew to dominate the harbor, and physical conditions deteriorated under the management of the state Department of Transportation.

In 2005 DOT argued that state law required HCDA to take over harbor operations because HCDA owned the property. (The Legislature gave HCDA ownership of the harbor in 1990.)

To prepare for the transfer, HCDA in 2007 produced plans to improve the harbor, which at that time had about one-third of its slips condemned or unfit for use.

Initially, the agency proposed spending $14 million to repair unusable slips and add new restaurants, a convenience store, a fuel station and other improvements to be financed by doubling slip rents and adding maintenance fees. Tenants complained that the plan would put them out of business.

HCDA revised its plans several times, and in 2009 took control of the harbor from DOT and retained California-based Almar to manage the property for a fee.

HCDA also raised slip rental rates less drastically and opened slips to recreational boats while giving priority to commercial vessels.

Following some state-financed repairs, Almar increased occupancy at the harbor to near 100 percent from 40 percent.

Then in 2012 HCDA proposed having Almar lease the harbor and carry out the agency’s renovation plan at a cost of $18 million as a way to have the private sector pay for the work and have it done faster. After a long delay with no decision, Hughes Corp. asked to compete for the job in 2014 and was tentatively selected that year, subject to finalizing details of a 30-year lease that can be extended to 45 years.

Under the lease, Hughes Corp. must pay HCDA $550,000 upfront plus annual rent that the agency previously estimated would total about $14 million over the first 30 years.