Washington State Route 141 Spur, also known as the Underwood Cutoff, will close west of White Salmon this Saturday for roadwork.  Washington State Department of Transportation maintenance crews will close both directions of the highway at milepost 5-point-6, near the White Salmon River.  The closure is scheduled from 6 a.m. to 6 p.m. on Saturday, while crews replace a damaged culvert beneath the roadway.  WSDOT says completing the work before winter will help protect the roadway and keep water flowing safely underneath the highway.  Drivers affected by the closure can use State Route 141 through White Salmon as an alternate route.  Motorists are asked to slow down, follow detour and directional signs, and use caution around the work zone.