The U.S. Department of Defense is awarding nearly $15 million to Joint Base Pearl Harbor-Hickam for environmental protection efforts, largely to preserve the Koolau watershed upland of the base. The area’s forests filter water headed for the aquifers serving Red Hill and surroundings, and hold off erosion of soil into the sea.

It’s a record-setting amount of money for this competitive award, yet a drop in the bucket in relation to expected expenditures on the Red Hill fuel tanks cleanup. Consider it collateral repair — and a reflection of the threatened watershed’s value.