HWY 410 Landslide/ Nile Community Update-Nov.2,2009
NACHES, WASH-
Pendleton Weather
Today: Mostly sunny, with a high near 48. Light south wind.
Tonight: Partly cloudy, with a low around 29. West northwest wind between 6 and 8 mph.
Tuesday: Sunny, with a high near 49. West northwest wind at 7 mph becoming east southeast.
Tuesday Night: Partly cloudy, with a low around 29. Calm wind.
Wednesday: Mostly sunny, with a high near 49. Light and variable wind.
Wednesday Night: Partly cloudy, with a low around 35.
Thursday: A 20 percent chance of rain. Mostly cloudy, with a high near 55.
Thursday Night: A chance of rain. Mostly cloudy, with a low around 35.
Friday: A chance of rain. Mostly cloudy, with a high near 50.
Friday Night: A slight chance of rain. Mostly cloudy, with a low around 37.
Saturday: A chance of rain. Mostly cloudy, with a high near 49.
Saturday Night: A chance of rain. Mostly cloudy, with a low around 35.
Sunday: A slight chance of rain. Mostly cloudy, with a high near 49.
Cell Service Update
The Office of Emergency Management has been “spurring” US Cellular for updates. Basically the time line they have promised for results has not materialized. In our conversations with them it has been explained that they are running into problems with making all the parts of system interface and work properly. We will continue to monitor the situation.
WSDOT Update
Conditions:
State Route 410 is open with detour between milepost 104 to milepost 108. The emergency detour route has been opened to all drivers, and is a rough, gravel-surfaced road. Crews continue work on portions of the detour and drivers on this emergency route could experience long delays due to construction activities. WSDOT could close the roadway for the safety of drivers at anytime. Information updates are available at 509-577-1635 or 5 1 1.Weather Today: Partly cloudy.
Key Issues Next Week• Complete subgrade on detour route
• Start paving detour route
• Continued work on re-channelization of the river
Road Design and Construction
Concurrent with the initial construction activities, the design of the 4,000-foot realigned detour section near the southwest Nile Valley wall was completed early in
the week. WSDOT and the contractor, Selland, are working 14 hour days, seven
days a week, to complete the construction of the SR 410 temporary detour to
provide a roadway that will withstand winter weather and increasing river flows.
The subgrade for the realigned section is 60% complete. Paving of the 2.5 mile
north section was delayed due to weather conditions, but we are optimistic that the
paving will be completed next week. As many as 32 contractor employees are on
the job, with an equipment list that includes 10 scrapers, five trackhoes, 17 dump
trucks, two backhoes, and four dozers. Fifteen of the 17 truck drivers are local to
the area.
Real Estate Activities
There are no changes from last week as all of the right-of-way for the new
temporary SR 410 detour on the southwest side of the valley, six parcels in total,
has been either purchased by Yakima County, or Rights of Entry have been
obtained to construct the new road.
Hydrology
WSDOT continues to support efforts by Yakima County and the U. S. Army Corps
of Engineers to construct the new Naches River channel prior to the anticipated
elevated river flows this winter. The new channel should be completed prior to
Thanksgiving. We are also conducting new analysis for a flood model for the Nile
Valley that will be available by mid November. The new flood model will allow
planning for future flood impacts based on the new channel.
Resource Agencies - Environmental
WSDOT continues to coordinate and communicate with resource agencies as we
construct the SR 410 detour road along the south valley wall. Actions include:
• Washington Department of Fish and Wildlife (WDFW) will remove
stranded fish within Carmack Ditch.
• Washington State Department of Ecology will de-commission domestic
Wells of purchased homes.
• WSDOT will consult with U. S. Fish and Wildlife Service (USFWS) and
National Marine Fisheries Service (NMFS) regarding the Endangered
Species Act.
• WSDOT will coordinate with the Yakama Nation and Department of
Archeology and Historic Preservation (DAHP) for an archaeological survey
on the SR 410 detour road and recommended cultural monitoring.
Geology
Monitoring the Slide
The GroundProbe radar unit arrived in Yakima as scheduled on Friday, October
23, 2009. The radar unit was set up at the Eagle Rock field site that afternoon and
was operational and collecting data that evening.
This monitoring site provides a clear and unobstructed view of the landslide area. A
communication link (via the Internet) between the radar unit and WSDOT’s
Geotechnical Division in Olympia will allow engineering geologists to monitor
radar output from their Olympia location. If the slide begins to move, the system
will immediately notify workers and engineers.
To date there appears to be no significant movement within the main body of the
landslide, although active rock fall from the bedrock rim and some minor raveling
of steeper slopes within the landslide is being detected.
Test Hole Drilling:
A comprehensive geotechnical site investigation plan has been completed. The
plan calls for drilling deep test holes at nine locations along three critical geologic cross-sections. The holes will be instrumented with slope inclinometer casing to monitor for ground movement within the test hole and piezometers to measure the location of groundwater. This information will provide the necessary subsurface information to fully develop the landslide failure models that are needed for further geotechnical stability analysis. The Geotechnical Division plans on meeting with region personnel early next week to make arrangements for a drill access road and drill pad construction. Once these are constructed, test hole drilling can commence.
Site Mapping:
Detailed surface mapping of the landslide was completed last week. Engineering
geologists from the Geotechnical Division spent three days mapping prominent
landslide features onto post-landslide air photo base maps utilizing mapping-grade
GPS to provide locations of these features. The data from this effort is being
compiled and analyzed for the purposes of developing a preliminary landslide
failure model that can be used for future geotechnical stability analysis. This
model won’t be complete until the planned test boring program has been
completed.
Supplementing this geologic field work, a draft landslide timeline has been
completed based on eyewitness account and University of Washington seismic
records of the landslide failure. The draft timeline confirms that the landslide
failed in a number of sections beginning in the late morning of Saturday, October
10, 2009, and culminating in the massive landslide failure in the early morning of
Sunday, October 11, 2009, a time period of approximately 18 hours. To complete
this timeline, additional interviews with eyewitnesses are planned once they are
located.
Other
The region investigated the feasibility of using Pyramid Pass and the Little Naches
Road as an emergency evacuation route to reach the west side but determined this
is not a safe or feasible emergency route. With the minimal snowfall this last
week, the route has proven to be unsafe for use.
Informational Websites that are potentially pertinent to you:
There is a lot of information out there. Please take a look and see if any applies to you.
(NEW) Yakima County Public Services Flood Control Zone District Flood Preparedness Information
http://www.yakimacounty.us/SurfaceWater/FloodPreparedness.htm
WSDOT Website with road and slide information
http://www.wsdot.wa.gov/News/2009/10/23-WSDOT+begins+building+SR+410+detour.htm
Yakima Valley Office of Emergency Management Blog KR Catlin is updating this daily
http://www.yak-oem.blogspot.com/
NOAA National Weather Forecast for 8 miles east of Cliffdell.
http://forecast.weather.gov/MapClick.php?lat=46.86394700508323&lon=-120.95947265625&site=pdt&smap=1&marine=1&unit=0&lg=en NOAA (Weather Service) river gauge at Cliffdell
http://www.nwrfc.noaa.gov/river/station/flowplot/flowplot.cgi?CLFW1
WA State Emergency Management Personal, Family, and Pet Preparedness Information http://www.emd.wa.gov/preparedness/prep_personal_preparedness.shtml
