Murder on the Columbia Dredge

What possible connection could there be between a dredge and an accountant from Seattle?
This book is set in the picturesque town of Newport on the Central Oregon Coast. It is a favorite tourist destination for those who live in both Portland and Seattle, although it retains its small-town atmosphere. Its residents enjoy the active commercial fishing harbor, as well as the unique attractions of an Aquarium and the Pacific Coast Center.
Each year the ocean currents move sand into the harbor entrance, creating a navigation problem for the fishing fleet residing in the port. In order to keep the channel open, the Columbia Dredge comes into Newport each year, to dredge the sand out of the channel.
Accountant, Hazel Davies, and Chaplain, Anna Kohl, unexpectedly find themselves entangled in a murder mystery, which has the detective in charge completely stumped.
Murder on the Columbia Dredge is the fourth mystery in this series.