In August, in response to ocean temperatures trending at slightly higher than typical temperatures, scientists braced for the possibility of a widespread coral bleaching across the islands — and asked oceangoers to report on the severity of damage.

With waters now cooling, the bleaching event has tapered and assessment of the summer impact has found that while scores of near-shore areas sustained hits, the damage was not as severe as feared. However, there’s now growing concern about increased frequency of events in which environmentally stressed corals turn white and brittle.

Corals can survive bleaching, but the chances of recovery decline the longer stressors continue. This should serve as a red-flag warning to better protect a valuable natural resource that’s largely out of sight, out of mind for many in Hawaii.

When healthy, Hawaii’s coral reefs support a thriving underwater ecosystem. They also serve as a coastal safeguard — providing more than $835 million in natural flood protection for the state annually, according to a recent U.S. Geological Survey report, conducted with The Nature Conservancy and the University of California-Santa Cruz.

Oahu’s share of the state total is the largest, $395 million in yearly flood protection, followed by Maui with $377 million.

Without reefs acting as submerged breakwaters — dissipating up to 97% of wave energy offshore — many of Hawaii’s beaches would quickly disappear, leaving shoreline properties vulnerable to the upshot of erosion.

While climate change and ocean acidification are exacerbating reef problems, scientists rank sewage contamination and other pollutants, including some sunscreen types, as leading troublemakers.

Front and center in a debate about the necessary scope of protection for reefs from land-based pollution sources is a Maui County legal dispute that went before the U.S. Supreme Court this month.

At issue is whether the county is violating the federal Clean Water Act (CWA), which bans the dumping of pollutants directly into surface waters, including oceans. At the heart of the Maui case is whether the CWA should also apply to indirect dumping — by way of injection wells.

Maui Mayor Michael Victorino chose to seek “clarity” on the matter from the high court rather than sign off on a settlement, which he views as a heavy financial lift. The Maui County Council had rightly wanted to settle, in order to move forward on needed fixes. Among other things, that would require the county to obtain a federal pollution permit and fund at least $2.5 million in projects to divert treated sewage from injection wells.

While a court ruling is not expected for several months, what’s clear is that the county’s daily injection well discharge of some 3 million gallons of wastewater into groundwater is seeping into the ocean and contributing to coral demise and algae blooms. For the sake of safeguarding reefs, the county should be held to the CWA’s regulatory standards.

Once known as a rare occurrence in Hawaii, the state has contended with three major bleaching events in recent years, resulting in major die-offs of corals. While warm ocean temperatures are the direct cause, residents and tourists alike can take steps to help minimize impacts.

Those include committing to the state’s “Coral Pledge,” a listing of common-sense actions that reduce stressors, such as using reef-friendly sunscreen and keeping detergents and chemicals out of storm drains. For more information, check out a state Department of Land and Natural Resources TV special, “Saving Coral,” slated to air on K5 at 8:30 p.m. Thursday.

Also helpful: DLNR is asking oceangoers to assist researchers by continuing to report bleached patches at hawaiicoral.org.