The West Broadway landslide has been creeping slowly towards Broadway at the rate of a quarter of an inch per month. That rate spiked last weekend during an earthquake with origins near Bondurant.
On Saturday, August 27th at approximately 3pm a 4.8 magnitude earthquake shook the valley. According to extensometer monitors located on the surface of the Budge Drive hillside measured a surface movement of approximately a tenth of an inch following this earthquake. Deeper instruments, called inclinometers, monitoring subsurface movement did not measure a significant increase down deep associated with this earthquake.
The Town of Jackson has started taking steps towards mitigating this slide area. Recently, Jackson and Teton County residents voted in support of a 1% Specific Purpose Excise Tax (SPET) to fund the stabilization of the Town’s portion of the slide.
The land above the slide was purchased by the Town of Jackson and the house which was located on this property was recently demolished to prepare for stabilization work. Prior to this a temporary drainage system was installed above the head scarp to divert water from the slide area as increased water content in the soil increases the possibility of greater movement of the slide. In addition, Budge Drive was widened to allow construction traffic to gain greater access to the area.
With the passing of the SPET, the Town of Jackson is moving forward with contractors to establish the project schedule, cost and quantity stipulated in the contract agreements.
It is anticipated that a temporary access road will be constructed to the west of Budge Drive beginning in mid to late September. This temporary road will allow residents of the area to access their homes without utilizing Budge Drive giving construction crews unimpeded access to Budge Drive for stabilization work.
Phase two of the mitigation work is slated to begin in mid-March early April 2017. This process will involve removing weight from the top portion of the slide while simultaneously installing sheer key buttresses along either side of Budge Drive. These operations will only mitigate the Town’s public right-of-way and protect public infrastructure including the Town’s main water line, a sewage main line and West Broadway. It is projected that this stabilization project will be completed by December of 2017.
Residents should note that the Town has both surface and subsurface monitors placed throughout the Budge Drive hillside to indicate any sort of abrupt movement. If such an abrupt movement was noted the public would be notified immediately.
For additional information on the landslide please visit the Town of Jackson’s website:www.townofjackson.com/government/slide-facts/