A city councilwoman, state representative and state senator say they are worried that a "catastrophic failure" could occur at a hillside subdivision construction site in Nuuanu that’s been blamed for triggering a rockfall and small landslides and causing cracks in neighbors’ homes.

Grading and other groundwork for the future Dowsett Highlands subdivision in Nuuanu "has resulted in conditions which would create risks to health and safety of area residents," stated an April 20 letter to the city Department of Planning and Permitting from state Sen. Suzanne Chun Oakland (D, Kalihi-Pauoa), Rep. Sylvia Luke (D, Pacific Heights-Punchbowl) and Councilwoman Tulsi Gabbard, whose district includes Nuuanu.

"We are greatly concerned about the possibility of a catastrophic failure that could result in severe property damage within the neighborhood," the lawmakers wrote. "We would like the City and County of Honolulu’s assurance that the safety and security of the area residents are not being compromised by this development."

David Tanoue, director of the Department of Planning and Permitting, told the Star-Advertiser in an email: "The department has not seen any indication of a catastrophic failure at the project. The project was designed by licensed professional engineers and consultants who have reviewed their design at the request of the department in response to neighbor concerns."

The lawmakers’ letter is likely to add even more political pressure on a project that already has resulted in having a city inspector on site every day in a neighborhood full of doctors, professors and even former Gov. George Ariyoshi.

"The neighbors in the immediate vicinity are very concerned," said John Harrison, former president of the Nuuanu Valley Association. "The letter is a very positive step. It shows a lot of courage."

Laumaka LLC paid $6.2 million to buy the 45-acre property in 2005 for as many as 18 future custom homes on nine separate lots in Nuuanu at the base of the Koolau Mountains.

In 2006, Laumaka LLC won a court battle against the Nuuanu Valley Association when a state judge denied a request to temporarily bar planning officials from approving the hillside subdivision.

Officials with Laumaka LLC did not immediately respond to telephone and email requests for comment from the Star-Advertiser.

The lawmakers’ April letter outlines a litany of potentially costly and dangerous problems related to the construction site:

» In 2009, a boulder estimated to weigh 1,000 pounds slammed into a home on Kahawalu Drive, and "the Department of Planning and Permitting determined that this incident was caused by the developer moving rocks and soil."

» Neighbors have seen "extensive erosion and fallen trees in the area. During a recent rainstorm, runoff was also seen going over a resident’s keystone wall rather than draining down to the detention basin. … The excessive runoff could also be caused by the possible improper design of the detention ponds behind the wall."

» "A number" of structures in the neighborhood have developed cracks that homeowners worry are caused by the project’s changes to natural drainage.

» Erosion, scouring and overflows have been caused by high discharges of water collected by new detention ponds for the project.

» Residents have experienced "small-scale landslides on their properties as well as documented land shifts on their properties. The residents are apprehensive that these events are precipitators to a larger-scale event which would be catastrophic for the area."

» The project has "deviated from its established plan" and a neighbor’s rock wall was demolished without permission. A 3-foot keystone retaining wall instead now stands more than 30 feet tall and a neighbor reports that it appears to be leaning forward. "The resident has major concerns that the wall is losing its structural integrity and will collapse."

Chun Oakland toured the area and confirmed that the 30-foot wall is leaning.

"Oh, my goodness," she told the Star-Advertiser. "There is a lot of concern."

Last month, Gabbard said her office received about a dozen complaints about the project, which had already received seven notices of violation from the city.

Harrison said he hoped the letter signed by Gabbard and the other lawmakers "shines more light on a situation in which there’s a long history of the sorts of problems that we’ve confronted."