Last July, in the heat of the crowded race for King County Executive, the King County Ferry District seemed all but doomed. Of the candidates running, only Dow Constantine was committed to staying the course with the fledgling transportation agency.

Luckily for that agency, Constantine emerged as the winner, and on Monday helped broker a deal that accomplished his goal of keeping the West Seattle and Vashon Water Taxi routes afloat while sharply lowering the KCFD’s property-tax rate from $22 to $1.20 per year on a $400,000 home, beginning in 2010. The deal also shelves plans to explore the establishment of a multiroute mosquito fleet.

Many peninsula dwellers would have breathed easy had the West Seattle Water Taxi simply been able to maintain existing service, which runs from April through October and has seen ridership double over the past four years. But thanks to the impending doom of the Alaskan Way Viaduct, an action that will disproportionately impact West Seattleites (whom it serves as the main artery to downtown), what in July looked like an especially bleak forecast for KCFD’s plans to expand the route to year-round service now looks pretty darn sunny.

In order to expand service to the months of November through March (beginning in Nov. 2010), KCFD needs to come up with an additional $250,000 or so annually. The likely source for that loot: A small slice of $33 million in state-approved mitigation money, which Constantine says the KCFD will be targeting “to help expand [Water Taxi] service during the [viaduct] construction period.” (The King County Department of Transportation makes recommendations for how funds should be used to the State DOT, which then authorizes the spending.)

The $33 million is tied exclusively to “south viaduct” mitigation, and is to be used through 2012. More funds will be made available for “central viaduct” mitigation, funds the KCFD could conceivably try to tap as well. Either way, the KCFD’s Board of Supervisors, which comprises the same personnel as the King County Council, voted to approve funds to retrofit the dock at Alki’s Seacrest Park, presently a hazardously wobbly obstacle for passengers disembarking the vessel. Dock construction is scheduled to be finished by the time the Water Taxi returns to service in April.