Clean up streams to stop flooding

It’s the calm before the storm — or the two storms that are anticipated within days. The hope is that beneath this calm there’s also a fair amount of scurrying to be sure Oahu has done what it can to prevent the most calamitous damage that can result.

Some of that is the devastation to streamside properties caused by flooding, when storm debris chokes drainage.

Myriad stories of such troubles were chronicled in the aftermath of Tropical Storm Darby, which dumped an enormous amount of rain on the islands as it passed. One particular tale of distress was the focus of a story appearing Monday, by Honolulu Star-Advertiser writer Gordon Pang. That article captured the experience of Khamla Phonsouvanh and his family, who live on Umi Street near Kalihi Stream. Because debris effectively created a dam toward the makai end of the stream, the water backed up and flooded the family’s apartment complex.

The displacement of that household and the financial loss was replicated around the island. To the greatest extent possible, that can’t be allowed to happen again.

City officials and other authorities likely have their next chance to demonstrate they have the problem in hand this week, as Hawaii nervously watches the advance of two powerful storms.

Two tropical storms, Madeline and Lester, have been on a track toward the isles. It’s uncertain whether either or both will be at hurricane strength at the nearest approach, but even under the best-case scenario, heavy rain leading into the Labor Day weekend is a real possibility.

Showers on the leading edge of Madeline’s system could arrive Tuesday over Hawaii island and Maui, reaching other islands later.

Residents around Umi Street told the Star-Advertiser that city crews cut tall brush in the streambed before Darby, but did not clear it out.

That practice must be corrected, although the fault for the stream blockage clearly lies with others as well. Many people upstream habitually dump large tree cuttings and even broken appliances and other junk into or adjacent to the stream.

This negligence by property owners is appalling. The city has a responsibility to keep sectors of streams under its control clear, a task on which it’s earned a less than optimal record.

However, it’s a shared duty. Residents living streamside, whether they own or rent their homes, are accountable for dealing with their household rubbish responsibly. Dumping things with the expectations that streams carry them away is unacceptable.

Now is the time for better preparations to kick into high gear. Fortunately, the wrath of Darby left a lasting imprint on Oahu’s officials, who witnessed that even the outer reaches of a storm can have severe effects.

Ed Manglallan, deputy director of the city Department of Facility Maintenance, said crews at each of the city’s corporation yards are drawing up work plans to clear segments of streams that are under city control in each Oahu district.

In addition, he said, because there is an imminent storm, the city also is getting clearance from the U.S. Army Corps of Engineers to clean out the areas at the mouth of the streams where they empty into the ocean, the zone within the corps’ jurisdiction.

The city also needs to do everything it can to ensure that its sewer system is at maximum capacity to deal with the possibility of excess storm runoff. During the Darby deluge, the overflowing storm drains brought pollutants that fouled the water.

Overcoming inertia — both at the bureaucratic level and among private property owners — is the imperative now. Given Hawaii’s advance warning of the storms, and with the memory of Darby still fresh, preventing a repeat of that dismal outcome should be the goal of the coming days, while the sun shines.