05
Jun

Northern California’s Highway 101 Moves Up and Out of Floodplain

The 2.5-mile portion of Highway 101 was recently opened in April and this decision has been hailed as progress for the usually congested Marin-Sonoma track popularly called The Narrows. The project is one of a kind with a conceived budget of 743 million dollars. This amount was earmarked to ensure that the menacing bottlenecks and gridlock associated with the road is cleared.

The execution of this project saw the Marin and Sonoma transport authorities in collaboration with the Caltrans coming up with a strategy to apportion the total task into 18 different contracts. In addition to these 18 contracts, there will be 4 extra contracts and this will involve adding carpool lanes to 2 additional segments.

The Narrows has been hailed as the panacea to the never-ending issue of traffic congestion in that area. Normally, the highway is expected to close once in a year as a result of excessive flooding, however, the degree of the storm goes a long way in determining the havoc caused. According to forecasts, we’re in for a turbulent bout of storms ahead and this makes The Narrows project particularly urgent.

According to an estimate provided, over 150,000 automobiles ply the Narrows route every day. This road was first planned in the late 1990s but did not gain approval until 2009. Two years after gaining approval, the execution of the project commenced in 2011. Those in charge of the highway moved it about 190ft to the west. This was done in a bid to soften the curve of the highway and make sure the road is not in the path of the floodplain. The highway was also upgraded to fit a 70 mph design.

There are 3 final miles remaining in the carpool lanes and preparations are ongoing with the project nearing the end of the preliminary stage. However, the Marin transportation authority has announced that it is in need of 105 million dollars to complete this project. Likely sources of the funds needed for this project include;

  1. State gas tax increase
  2. Bridge toll hike

Sonoma County has announced its plans to finance the remaining part of the project; the carpool lanes via the local sales tax. The county also expects funds from the gas tax increase.

The just-completed 2.5 mile Narrows segment boasts a centerpiece- the 510-ft-long bridge. This bridge stretches over the San Antonio Creek and it was built to withstand a 7.0 magnitude earthquake. This bridge is also expected to remain intact through a 100-year-flood.

This bridge serves as a replacement for two 120-ft-long bridges in parallel. The drawback was that it wasn’t equipped with adequate openings and so, the creek (usually flooded) didn’t have an outlet. As a result, the new bridge was built to be 5 ft. higher and it doesn’t restrict the creek’s path.