Monitoring project gauges health of Maunalua Bay
POSTED: Wednesday, November 12, 2008
East Oahu's scenic Maunalua Bay, stretching from Diamond Head to Koko Head, is undergoing a thorough physical exam.
Nine instrument packages, including a camera system, were installed on the ocean floor in the bay over the weekend. Every five minutes, the instruments measure temperature, salinity, currents, waves, tides, winds, turbidity and other aspects of the water.
A weather station, rain gauge and camera system also were deployed atop the 22-story Mountain Terrace Condominium on Kawaihae Street to keep an eye on the weather and water in the bay and compare observations.
Popular for water sports, fishing and picnics, the bay includes seven miles of beach and 6 miles of water. More than 60,000 people live in the area.
U.S. Geological Survey and University of Hawaii Kewalo Marine Laboratory scientists are conducting a comprehensive study of the bay. They're working with Malama Maunalua, a community group dedicated to conserving and restoring the bay, other organizations and a host of state and federal agencies.
Mike Field, senior marine geologist and project chief for the USGS Pacific Coral Reef Project, said: "Everybody is in agreement that the overall water quality and overall health of the bay are not what people would like it to be."
Sediment from land runoff is one of the prime causes of reef deterioration and one of the major problems facing coral reefs in Hawaii, Field said.
He was here with six scientists from the USGS Pacific Science Center in Santa Cruz, Calif., whose expertise is on sediment transport and pollution.
Robert Richmond, a world leader in coral reef conservation at the Kewalo Marine Laboratory, and other UH scientists have been engaged in research on the water, land and streams at Maunalua Bay.
Field's team came here with instruments and devices they've modified for research on coral reefs, including an imaging system that sits on the bottom aimed at a particular coral colony and snaps pictures of it six times a day, he said.
Instruments will tell them if the water quality is poor and a lot of sediment is in the water but "it doesn't tell us if sediment is landing on the coral," Field said. The photos every four hours will show if that is occurring and if the coral is being swept away with the next wave or starting to cover the surfaces, inhibiting recruitment of new coral in spawning season, Field said.
Curt Storlazzi, USGS research geologist and oceanographer in charge of the oceanographic work, and his colleagues flew home yesterday after completing installation of nine instrument packages.
Using GPS satellite positioning, they spread them across the bay to just outside the reef crest and to a depth of about 70 feet, Storlazzi said. The weather station, rain gauge and camera (snapping pictures every two hours) placed on the Mountain Terrace condo roof with manager Richard Boyd's assistance will help the scientists compare information above and below the ocean surface, Storlazzi said.
For example, "When we see things like all the currents heading to the west, is it because of strong tradewinds or how the winds are blowing? If the water is turbid, is it because of material on the reef flat or streams discharging sediment in a rainfall?
"We're trying to understand the natural processes first," Storlazzi said. "Then we can better understand the human impacts ... and how effective remediation processes will be."