Hawaii’s rainy season is under way, and with it flows concerns in flood-prone Windward Oahu.

"There are issues that come up every year," said David Henkin, chairman of the Kahaluu Neighborhood Board.

But city and state crews have been busy with stream and storm-water channel clearing, as well as making some bridge repairs, to reduce the chance of flooding caused by blocked, overflowing streams.

Yesterday morning, crews from the city Department of Facility Maintenance cleared blockages in a drainage system in Kaneohe, near the intersection of Kamehameha and Kahekili highways.

"The city prepares year-round to mitigate flood hazards," said Louise Kim McCoy, press secretary for Mayor Peter Carlisle. "Heavy rains can occur at any time, so DFM (Department of Facility Maintenance) tries to keep clear city streams and drainage systems when problems are discovered."

The city also will inspect private steam areas for blockages and can issue citations if they are not maintained by the owner. Debris can cause blockage either at the private stream area or downstream at bridges or other constricted areas.

Stream-clearing efforts usually involve removing vegetation and debris, which can include illegal waste such as trash or concrete discharge.

The state Department of Transportation has placed heavy equipment at base yards around Oahu so crews can respond quickly to flood threats, DOT spokeswoman Tammy Mori said.

State landscaping crews have been checking storm drains, and clearing branches hanging over Pali and Likelike highways. Repairs on the South Punaluu and North Kahana bridges are also under way.

There are 26 bridges in the Koolauloa area, many of them over streams prone to flooding, Koolauloa Neighborhood Board member Junior Primacio said.

"A lot of them are old bridges, going back to being 86 years old," Primacio said. "With the two bridges being rebuilt, that’s going to help curb a lot of the flooding issues."

Henkin of Kahaluu said there are a number of areas that cause problems in his area, including the Waikane stream and low-lying areas such as Pulama Road.

"We’re a low-lying area with a lot of rainfall, a lot of streams and a highway that’s not too high above sea level," Henkin said. He said he hopes the bridge repair at Punaluu and Kahana would alleviate flooding down the coast.

The National Weather Service says the state’s rainy season typically begins around October or November. The past few days saw some rain. Mount Waialeale on Kauai had 7.9 inches of rain in the 24-hour period ending at 8 a.m. yesterday. Parts of Windward Oahu and the Big Island received up to 3 inches of rain in that period.

Weather Service lead forecaster Tom Birchard said 2010 is not forecast to be unusually wet but that the La Nina climate pattern, with cooler-than-normal ocean surfaces, is expected to bring higher rainfall in 2011 through April.