Sound Transit to start field work for planned Link light rail expansion

20150423_MAP_Lynnwood-Link_402x663To evaluate and refine the final design of the planned Link light rail expansion, Sound Transit said Friday that over the next several months its representatives will be contacting property owners for approval to access private property in order to conduct geotechnical drilling, utility potholing and survey work.

After receiving approval from property owners in the form of Right of Entry authorizations, work on private and public properties will take place along the Interstate 5 corridor between Northgate and Lynnwood. This work will include:

Utility potholing

Potholing involves drilling small holes to locate existing underground utilities. In this round of potholing, crews will be drilling in areas to confirm that no utilities exist underground in areas that will be excavated for the future route or stations.

Geotechnical drilling

In order to study soil and groundwater conditions, drilling or “borings” are necessary to collect soil samples for analysis and install groundwater monitoring devices. A drill rig and truck will perform borings that will remove soil and install a monitoring device at each site.

Crews will be monitoring water levels by visiting these sites to take measurements throughout final design of the project. Each hole will be covered with a metal plate until they are refilled and patched to match previous conditions as closely as possible. In accordance with all local regulations, borings will be done carefully to avoid soil erosion and dirt or mud from leaking into surface waters, wetlands and drainage systems. Each site may take about three days to complete.

Land surveys

Civil surveyors will gather topographical information and may leave temporary paint markings, survey nails on the ground or ribbons in trees. Small holes may be dug, but will be refilled. Survey flags may also be placed to indicate boundaries and should remain in place until they are removed by staff.

Tree surveys

Survey crews will evaluate existing trees in the Interstate 5 right of way and on private property potentially acquired by the project to assess future tree removal. Trees located where the route or stations exist will need to be removed to build the project as well as trees that pose a risk to future train operations.

For more information about the Lynnwood Link Extension project, contact Roger Iwata at 206-689-4904 or

You can also visit the Lynnwood Link Extension web page.

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