City Council Resolution 204, which would approve a new joint federal-city study of flood-control options for Wailupe Stream, is headed to the full Council for consideration after its Zoning Committee advanced it last week. For longtime East Oahu residents, this may feel like deja vu, as flood control for the Wailupe waterway has been studied multiple times over past decades.

Why do it again? Well, in 2018, a flash flood from Wailupe Creek took out three homes and damaged more than 150 others. The waterway and surrounding homes, stretching from Maunalua Bay mauka to upper reaches of Aina Haina, remain exposed to flood risk. Further, both research and experience now indicate that Hawaii’s risk of damaging floods and storms is rising, along with sea levels and global temperatures. Aina Haina residents in the Wailupe watershed have long worried about flood risk, and these are good reasons to worry more intensely.

However, what’s missing from Resolution 204, which proposes to commit $1.5 million of city money to a $3 million study of engineered flood control in the watershed, is acknowledgment of the competing cultural and environmental concerns that are attached to the stream. Wailupe Stream, largely unlined with concrete, is the last of its kind in East Honolulu, and valuable for its beauty and environmental benefits. It supports native species, lowers surrounding temperatures and is a site for traditional subsistence fishing and cultural practices.

The measure would authorize the city Department of Design and Construction (DDC) to work with the U.S. Army Corps of Engineers (USACE) on planning flood-control features such as a concrete-lined stream, retaining walls and water-retention basins. If moved forward, the project will cost tens of millions of dollars and could have negative environmental consequences. Therefore, it’s flippant for the resolution’s sponsor, Council Chair Tommy Waters, to say, “If we don’t like what they (USACE) come up with, we can simply say, ‘We don’t like that.’”

Instead, to ensure that the city develops a feasible plan, rather than another study that is shelved, the City Council must amend this resolution to require that planning incorporates full consideration of potential obstacles and consequences, and includes environmental conservation and less-destructive “green” infrastructure elements to the maximum extent feasible.

Just last year, Malama Maunalua was among partners awarded an $8.1 million federal grant from the National Oceanic and Atmospheric Administration (NOAA) for a “Ridge to Reef Project” to restore native forest ecosystems in the Maunalua watershed and to use green infrastructure, which mimics or expands upon natural processes so that more water is absorbed upstream, water quality is improved and stream flows are moderated.

Ridge to Reef and projects like it must be leveraged to lessen flood risk, providing the best cost-benefit returns. That’s an issue Waters should be prepared to address with constituents — before the Council presses forward with this engineering “construction project,” as city DDC Director Haku Milles called it.

Flood control is costly. A 2007 USACE flood control study contemplated 6- to 8-foot flood walls along portions of Wailupe Stream and other construction with an estimated cost of $40 million, and ultimately, USACE concluded that the construction would not meet cost-benefit guidelines.

A proper next step, before the Council votes on Resolution 204, is to open this matter to a full discussion with members of the community, scheduling an additional committee hearing to consider necessary amendments. The city can’t afford to make a plan without incorporating green infrastructure and conservation, at the cost of additional damage to Wailupe Stream and Hawaii’s environment. Once destroyed, these can never be replaced.