MAPUNAMAPUNA (HawaiiNewsNow) – The city believes flooding that swamped roads and inundated businesses in Mapunapuna Tuesday morning was the result of clogged storm drains and not a failure of its new $600,000 flood control system.
When the tide is high the intersection of Ahua and Kilihau Streets is below sea level. Ocean water travels inland through storm drains and spills onto the roads.
Earlier this year the city installed duck bill check valves to keep the tide at bay. The duck bill valves allow runoff from rainwater to drain into the ocean, but when the tide rises pressure from ocean water forces the valves shut.
Tuesday morning the high tide coincided with heavy rain. The duck bill valves may have been closed by the high tide, but when it receded rain water should have drained into the ocean. It did not.
The city believe storm drains are clogged somewhere between the street and the duck bill valves.
A crew will attempt to remove the blockage Wednesday morning.
In the meantime people in the affected area of Mapunapuna can expect another flood Wednesday. The high tide will peak at about 6:35 a.m. Wednesday.