Mason - GRAPEVIEW LOOP ROAD - 2
Project Number: 1171
From milepost 2.15 to milepost 3.3
RATA Funds: $1,030,000
Legislative District: 35
Status:
Date Approved: 2003
Grapeview Loop Rd. is located on the western shore of Puget Sound’s Case Inlet. It provides the only access to the historic town of Grapeview, Stretch Island, and Treasure Island, connecting on both ends to SR 3, in Mason County.
The 2012 Grapeview Loop Rd. Project, CRP 1379, was part of a 3 phase reconstruction project. This particular section, MP 1.4 – MP 3.2, had very narrow lanes and shoulders which posed a serious safety hazard. The various curves and undulations also contributed to a history of 30 accidents on a road with an ADT of just 800. Other contributing factors to safety that were addressed included: poor horizontal and vertical site distances, narrow driving lanes and shoulders, inadequate clear-zones, poor pavement conditions, failing subgrade, and drainage deficiencies.
Mason County engineering staff designed the new road to meet minimum WSDOT design standards. Before and during construction, Mason County worked with the public to address areas of concern with drainage and erosion control by building rock walls and placing geotextiles. The horizontal and vertical curves were designed for a design speed of +5 mph faster than the posted speed, which greatly improved site distance. The road was widened from 11’ lanes and 3’ shoulders to 12’ and 5’, respectively. The county bought an average of 60’ of ROW, which made it possible to remove danger trees and obstructions that were within 14’ of the traveled way; on fill slopes and to the back of drainage ditches on cut slopes. Failing subgrade was excavated, hauled off site, and replaced with WSDOT approved gravel borrow and spalls.
The county was also tasked with installing a 14’X10’X180’ fish friendly concrete box culvert. The existing culvert was deemed a fish passage barrier due to its steep slope, improperly countersunk, and being only 3’ in diameter, severely undersized. The new culvert accommodates natural sediment and large woody debris transport. The barrier correction alleviated all of the fish passage issues at this site, and also improved the function of natural stream habitat in the vicinity.
The 2012 Grapeview Loop Rd. Project, CRP 1379, was part of a 3 phase reconstruction project. This particular section, MP 1.4 – MP 3.2, had very narrow lanes and shoulders which posed a serious safety hazard. The various curves and undulations also contributed to a history of 30 accidents on a road with an ADT of just 800. Other contributing factors to safety that were addressed included: poor horizontal and vertical site distances, narrow driving lanes and shoulders, inadequate clear-zones, poor pavement conditions, failing subgrade, and drainage deficiencies.
Mason County engineering staff designed the new road to meet minimum WSDOT design standards. Before and during construction, Mason County worked with the public to address areas of concern with drainage and erosion control by building rock walls and placing geotextiles. The horizontal and vertical curves were designed for a design speed of +5 mph faster than the posted speed, which greatly improved site distance. The road was widened from 11’ lanes and 3’ shoulders to 12’ and 5’, respectively. The county bought an average of 60’ of ROW, which made it possible to remove danger trees and obstructions that were within 14’ of the traveled way; on fill slopes and to the back of drainage ditches on cut slopes. Failing subgrade was excavated, hauled off site, and replaced with WSDOT approved gravel borrow and spalls.
The county was also tasked with installing a 14’X10’X180’ fish friendly concrete box culvert. The existing culvert was deemed a fish passage barrier due to its steep slope, improperly countersunk, and being only 3’ in diameter, severely undersized. The new culvert accommodates natural sediment and large woody debris transport. The barrier correction alleviated all of the fish passage issues at this site, and also improved the function of natural stream habitat in the vicinity.