Icicle Creek Engineers Projects

Mill Pond Dam Decommissioning Geotechnical Investigation and Slope Stability Study Seattle City Light Pend Oreille County, Washington

Seattle City Light (SCL) plans to decommission the Mill Pond Dam, located in a remote area of Pend Oreille County, Washington. This dam, part of the Sullivan Creek Hydroelectric Project - FERC No. 2225, does not currently perform hydroelectric functions or store water within the Sullivan Creek system. It was formed when a log crib dam was constructed in 1909 by the Portland Cement Company. An un-gated concrete dam, built in 1921 and retrofitted several times since then, is located just below the log crib dam. It is 134-feet long and about 55-feet high. It has historically maintained the water surface elevation of Mill Pond at approximately 2,520 feet NAVD 88. The area of the impoundment is approximately 64 acres. A primary goal of the design concept for the removal of the dam is to retain and stabilize on-site the sediment currently impounded in Mill Pond.

ICE contracted with SCL to complete the geotechnical investigation and slope stability study; this study involved characterization of the sediment, soils, and bedrock as necessary to complete slope stability analyses and to make slope stability design recommendations. To aide future design to reestablish the course of the natural stream, an additional component of the study is to characterize the nature and elevation of the sediment deposited by Sullivan Creek and other geologic processes prior to the construction of Mill Pond Dam.

To complete the site characterization, ICE worked closely with the regulatory agencies involved, including Pend Oreille County, Pend Oreille County PUD, Washington State Department of Fish & Wildlife, the US Forest Service and the US Army Corps of Engineers. Through these agencies, ICE obtained approval to proceed with the field explorations; permits included the Joint Aquatic Resource Permit Application (JARPA), and the Hydraulic Permit Application (HPA).

The field exploration program completed in late 2010 included geological reconnaissance, drilling and geophysics. Sixteen borings were completed, with 11 borings completed from a barge in the pond, and 5 borings in the delta and upland areas around the pond. All borings presented a challenge with regard to difficult access and stringent regulatory oversight. A major creek crossing was involved in several of the borings and with the over land geophysics. Geophysics completed over water and over land included refraction, reflection, side scan sonar and electromagnetic conductivity. Selected soil samples obtained from the borings are being tested for grain size, unit weight (density), direct shear, atterberg, hydrometer, permeameter, direct shear, consolidation, consolidation (drained and undrained) triaxial, organic content and moisture content. Rock samples are being tested for unconfined compressive strength.

The results of the field explorations and extensive laboratory soil testing program were used to evaluate site conditions and slope stability for the planned dam decommissioning. The study was completed in late 2011.

Beaver Dam Dike 3 Grout Curtain US Army Corps of Engineers and Nicholson Construction Company Eureka Springs, Arkansas

ICE provided a Geologist and a Lead Licensed Geologist to monitor drilling (overburden and rock core sampling) of the Beaver Dam Dike 3 grout curtain project near Eureka Springs in northwest Arkansas. The initial task included coring six exploratory borings as a means to evaluate the dike core condition (clay) and underlying bedrock formation (Cotter Formation Dolomite). Dike 3 had been leaking for several years with the suspicion that certain layers within the underlying bedrock may contain "solution features" (voids and caverns) that may be causing water from the impoundment to pass under the dike. Based on the results of the exploratory borings, ICE developed a geologic cross-section that characterized the dike materials and underlying bedrock. The bedrock was subdivided into four distinct (mappable) rock units referred to as Units 7, 8, 9 and 10. Unit 9 contained voids and caverns, and the underlying Unit 10 appeared to be massive (no voids). The grouting program was designed based on this geologic cross-section, with the grout holes extending to a depth of about 60 feet so that the grout curtain would bottom in the massive Unit 10 bedrock. The grout program continued for several months during which time ICE's geologist monitored and logged each grout hole, while noting voids or other anomalies. We also monitored lake levels and ground water in existing piezometers throughout the drilling/grouting process to evaluate the effectiveness of the grout curtain. The project was completed in Summer 2011.

Howard Hanson Dam Drainage Tunnel Improvements US Army Corps of Engineers and Malcolm Drilling East King County, Washington

ICE provided up to three Licensed Geologists to monitor drilling (sonic and percussion drill sampling) of exploratory drill holes for the installation of vertical and horizontal drains in the right abutment of the US Army Corps of Engineers (USACE) Howard Hanson Dam on the Green River near Ravensdale, in east King County, Washington. The purpose of the drilling was to install permanent dewatering wells designed to lower the short- and long-term ground water levels within the right abutment during high pool conditions. ICE's Geologists prepared a detailed boring log for each drain location using USACE standards and protocol. Our Geologists evaluated soil and bedrock characteristics and a means to understand the geologic history of the right abutment materials (pre-historic landslide deposits). Soil samples were obtained by our Geologists for grain size analysis testing. ICE also provided a Licensed Geotechnical Engineer and Hydrogeologist for designing the drains. This design involved evaluation of the grain size laboratory results, review of field (boring) log results and geologic interpretation of site conditions for developing the appropriate well screen and filter pack. The project was completed in late 2011.

Proposed Carpenter Substation (Yorke Property), Lacey, Thurston County, Washington

ICE provided geotechnical engineering and environmental services for the proposed Carpenter Substation site located in Lacey and Thurston County, Washington. The approximately 3-acre proposed substation site will include two dead-end towers and two transformers. Typically, these facilities are supported on concrete pads designed for an allowable soil bearing pressure of 1,500 pounds per square foot (psf). The site is located in an area of historic gravel mining, and is underlain by glacial outwash. ICE’s geotechnical services included site reconnaissance, excavation of 11 test pits, laboratory testing, evaluation of geologically hazardous areas, recommendations for site preparation and grading, underground utility trench backfill materials including the suitability of excavated materials for use as backfill and bedding, recommendations for foundation support, including minimum footing dimensions, embedment depths, allowable soil bearing pressures and settlement estimates, support of on-grade slabs including criteria for a capillary break and subgrade modulus, lateral earth pressures including active pressures for retaining walls and passive earth pressures on footings, for pavement subgrade preparation, seismic design criteria based on the 2006 International Building Code and surface and subsurface drainage requirements. In addition to geotechnical services, ICE completed a Phase I Environmental Site Assessment of the property, and identified concerns related to long term storage of hazardous materials at the site.

Sound Transit M Street to Lakewood Track and Signal Project, Pierce County, Washington

The M Street to Lakewood Track and Signal project will upgrade seven miles of existing track and street crossings in the Lakeview Subdivision rail corridor from South M Street in Tacoma to Bridgeport Way SW in Lakewood.  Construction on this project will begin in Spring 2009. ICE is on the AECOM project team to provide geotechnical services during construction regarding the earthwork aspects of this project. ICE will use its in-house soils laboratory for grain size analysis and compaction testing.

Mountlake Terrace Freeway Station, 90% and 100% PS&E, Mountlake Terrace and Snohomish County, Washington

ICE provided geotechnical engineering services for constructability review of the 90% and 100% PS&E design plans for the Mountlake Terrace Freeway Station located in Mountlake Terrace and Snohomish County, Washington. ICE reviewed available geotechnical reports and the 90% and 100% design plans for the project with a focus on constructability. ICE provided WSDOT with written comments summarizing these reviews and attended two full project team meetings at the WSDOT office in Shoreline.

Electron Flume Rockslide Assessment and Repair, Pierce County, Washington

An approximate 140-foot section of an elevated nine-mile long wooden flume structure was destroyed during a naturally-occurring rockslide on November 20, 1997. ICE provided emergency response to evaluate the condition of the rockslide and remaining flume structure as an initial assessment for safety issues and repair options. Because of the loss of revenue to Puget Sound Energy while the flume was off-line, ICE immediately scheduled and completed geologic reconnaissance (some of which required safety ropes because of extreme terrain) and subsurface exploration including high angle rock drilling and geophysics. ICE evaluated the site data and developed recommendations for rock-bolting the flume structure to the rock face. The rock face was inclined at about a 60 to 80 degree angle and consisted of igneous rock (andesite). In order to properly design the rock-bolt system, ICE was required to assess the strength characteristics of the rock and to evaluate rock fracture patterns for determining rock-bolt length. The field work and analyses were completed within a two month period with flume reconstruction completed within four months after the failure which was ahead of the anticipated schedule by PSE.

Homestead Valley Pit Reclamation, North Bend Area, King County, Washington

The Homestead Valley Pit near North Bend, Washington, has a relatively long history of slope instability and erosion problems. The property owner, Fiorito Brothers, Inc., and the Department of Natural Resources Division of Geology and Earth Resources (DGER – David Norman, Assistant State Geologist), encountered technical differences during the pit reclamation process. Because of this problem, ICE was retained by Fiorito Brothers, with approval by DGER, to provide a third-party opinion and recommendations in order to complete the pit reclamation process. ICE reviewed available geological and geotechnical information from the DNR and our in-house technical library to evaluate the regional geologic setting and slope stability conditions in the vicinity of the Homestead Valley Pit, completed a detailed geologic reconnaissance of the Homestead Valley Pit and adjacent areas, and developed an understanding of the geologic setting. This geologic setting included site geomorphology, soil, and hydrogeologic conditions of the Homestead Valley Pit as a basis for providing our opinion as to the most effective methods to reclaim the pit with respect to slope stability, topsoil development and reforestation. ICE also evaluated and provided a practical solution for the removal of two car-sized boulders precariously perched in a sand cliff.

State Route 410 (Chinook Pass) Roadway Washout Repair, Yakima County, Washington

ICE evaluated the roadway washout that closed one lane of State Route (SR) 410 in early 2008 about one mile east of Chinook Pass in Yakima County. During the snowmelt before the road was reopened in Spring 2008, uncontrolled surface water runoff caused severe erosion of the downhill embankment/slope resulting in soil loss on the surface and undermining of the roadway pavement shoulder. Upon the reopening of SR 410 on June 5, 2008, the road in this area was reduced to one-lane traffic until a repair method for the washout was evaluated and constructed. Brian Beaman of ICE met with representatives of WSDOT, including David Jenkins, the WSDOT Project Manager, Paul Gonseth, the WSDOT Project Engineer, and Brian Bell, WSDOT Chief Inspector, to observe the existing site conditions and to discuss repair options for the washout.

ICE provided support to the WSDOT Project Office related to the geotechnical aspects of roadway stabilization and washout repair. As part of this support, ICE 1) reviewed geologic maps to evaluate site geology and complete a geologic and geomorphic reconnaissance of the affected site and adjacent areas, 2) observed the drilling of one rock core, 3) described and characterize soil/bedrock and ground water conditions at the site, 4) evaluated the present stability of the roadway embankment/slope and the effects of the roadway stabilization methods on future slope stability, 5) provided recommendations for soil/bedrock excavation, 6) provided seismic design criteria based on the 2007 American Association of State Highway and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) manual with 2008 interim revisions (4th Edition), and 7) provided recommendations for a Hilfiker welded wire wall and soldier pile wall (cantilevered and tie-back). Successful repair of the roadway with a soldier pile wall was implemented in late 2008.

Suncadia Resort, Kittitas County Fire & Rescue District #7, Stormwater Infiltration Evaluation, Roslyn Area, Kittitas County, Washington

Suncadia LLC, as part of their agreement with the local communities, provided the design for the new Kittitas County Fire & Rescue District #7 fire station located near Roslyn, Washington. Icicle Creek Engineers provided hydrogeologic consultation related to the disposal of stormwater from the impervious areas of the fire station site. Our infiltration field testing was completed in general accordance with the Washington State Department of Ecology 2004 Stormwater Management Manual for Eastern Washington. Field infiltration testing was completed using a large scale Pilot Infiltration Test (PIT) which is the preferred method of evaluating short-term infiltration rates.

Permitting Review and Regulatory Oversight, Oil and Gas Exploration Projects, various counties in Washington State

Icicle Creek Engineers has provided permit review services and regulatory oversight to the DNR since October 2008. ICE has been working directly with Dave Norman, State Geologist for the DNR Division of Geology and Earth Resources; Mr. Norman serves as Oil and Gas Supervisor for the DNR. Services include all aspects of SEPA Checklist review including providing comments related to deficiencies in the SEPA Checklist, review of site plans and local regulatory agency (county) critical areas requirements, site visits to assess site conditions relative to the SEPA Checklist, review and provide response to public comments and attendance at public meetings. Permit review services include the Oil and Gas Drilling Permit Application to the DNR; these applications were reviewed and written comments provided to the DNR, along with recommended permit conditions. ICE has been requested to interface with the permit Applicants (companies planning oil and gas exploration activities), a variety of public agencies, including Ecology, air quality agencies (such as Southwest Clean Air Agency) and the general public, including opposition groups. ICE has reviewed related permit applications including air quality permits, stormwater discharge permits, grading permits, spill prevention and control plans, fluids and solids management plans, and temporary erosion and sediment control plans.

Warehouse Addition and Parking Improvements, Factoria Service Center, Bellevue, Washington

ICE provided geotechnical engineering services for an addition to an existing warehouse, including a two-story structure constructed with concrete masonry units and a steel-frame structure. ICE’s services included a geologic reconnaissance of the project site and adjacent area, along with exploration of the subsurface soil and ground water conditions in the area of the proposed building addition, and parking improvements by completing five test borings. The borings were drilled within the proposed building addition/parking area footprint using a truck-mounted drill rig subcontracted to ICE. The truck-mounted drill rig was selected because it causes far less damage to existing paved areas than a backhoe. ICE provided recommendations for earthwork, foundation design, support of slab-on-grade floors, surface and subsurface drainage systems, and the design of pavement sections for access and parking areas. ICE provided design plan review and construction observation services through project completion in 2009.

US Army Corps of Engineers Howard Hanson Dam Grout Curtain Project, King County, Washington

This ongoing high profile project involves coordination with a large project team led by the US Army Corps of Engineers for the installation of an approximately 450 foot long, 150 plus foot deep grout curtain to control seepage through the right abutment of the Howard Hanson Dam on the Green River. ICE is responsible for establishing geologic control by overseeing the logging of approximately 50,000 feet of Sonic coreholes into the embankment. As part of this responsibility, we are managing three Licensed Geologists (LGs) who work a 24-hour per day, 6 days a week schedule. Our LG’s are responsible for logging soil and rock core for the purpose of understanding subsurface soil and rock conditions and for planning the grouting program being implemented by Nicholson Construction Company, the Prime Contractor.

State Route 20 (Sherman Pass) Road Embankment Stabilization, Ferry County, Washington

ICE evaluated erosion that encroached under the paved shoulder of SR 20 in early 2008 about three miles east of Republic in Ferry County, Washington. During the past several spring snowmelts, uncontrolled surface water runoff caused severe erosion of the downhill embankment/slope resulting in soil loss on the surface and undermining of the roadway pavement shoulder. Interim repairs by WSDOT were proving ineffective. ICE worked with WSDOT to develop road embankment repair options, including a mechanically stabilized earth (MSE) wall and a gabion wall (gravity wall). We observed the drilling of three rock cores by a WSDOT drill crew, evaluated site geologic and overburden/rock character, and provided analysis and recommendations for these repair options. Seismic design criteria was provided based on the 2008 AASHTO LRFD.

Camp Creek Landslide Evaluation and Repair, Issaquah, Washington

The Camp Creek Landslide occurred in January 2004 on a steep hillside overlooking Interstate 90. The debris runout from this landslide temporarily closed the westbound onramp to I-90 at the Sunset Interchange. ICE was involved as part of a large technical group, referred to as the “White Paper Team” to evaluate the cause of the landslide. In addition to evaluating the cause of the landslide, we were specifically tasked with developing repair options for the landslide. Specific challenges for design included requirements that no artificial materials, such as drainage pipes or a non-aesthetic surface could be used (such as rock spalls). Further adding to this design challenge was the requirement to be able to freely pass up to 4 cubic feet per second of ground water seepage flow. ICE completed detailed geologic reconnaissance of the landslide area to locate ground water springs and hydraulic conductivity testing on large rock material as part of this effort. We developed a landslide repair that balanced the engineering requirements and agency needs to buttress the landslide and also to convey the ground water seepage, and still result in an aesthetic repair product. The landslide was repaired in late 2007 and ICE is continuing to observe post-repair performance.

Steep slope evaluation at the Suncadia Resort near Roslyn, Washington

ICE routinely conducts steep slope evaluations for the purpose of providing recommendations for building setback and buffer distance criteria. This photograph was taken adjacent to one of the building lots at the Suncadia Resort project near Roslyn, Washington.

Subsurface exploration at a proposed stormwater detention pond site near Issaquah

The proposed stormwater detention pond is located in a forested area with difficult terrain. The difficult terrain requires the use of track-mounted drilling equipment to access these areas. The area in which this drilling occurred is where an 80 foot deep cut is necessary to construct the stormwater pond. Subsurface issues include soil types for excavatibility and reuse as fill, and ground water levels that may be encountered at the time of construction.

Mine opening exposed during the installation of a deep sewer line

Many cities, including Issaquah, Renton, Black Diamond, Roslyn, and Cle Elum, are underlain by abandoned underground coal mines. ICE has developed an expertise in the evaluation of these abandoned mines for the purpose of delineating areas to avoid (Severe Coal Mine Hazard Areas) and areas that may be developed (Moderate Coal Mine Hazard and Declassified Coal Mine Areas). In this particular situation, the mine opening was concrete lined and descended into the ground at a relatively steep angle. ICE provided a reclamation plan to seal the mine entry.

Inside an abandoned underground coal mine

This photograph was taken inside of the abandoned underground coal mine entry shown in the previous photograph looking back toward the ground surface.

 Twenty-foot high "Mechanically Stabilized Earth" (MSE) wall system at the Woodside project in Renton (King County), Washington

The Woodside project included the design and construction of approximately one mile of new "connector roads" to the project site followed by the construction of over 500 new homes along with paved street access and underground utilities. As part of this project, an approximately 800-foot long and up to 20-foot high MSE wall system was constructed adjacent to a steep slope area. Geotechnical challenges for the MSE wall system included an evaluation of an appropriate MSE wall "setback" from steep slope areas, foundation support and drainage considerations.

One-million gallon water tank at the Woodside Project in Renton

A one-million gallon water tank was constructed on a bedrock high point within the Woodside residential project in Renton (King County), Washington. Geotechnical challenges included excavation of bedrock for the tank foundation and subgrade preparation for uniform support for the new water tank.

King County North SPAR project in Issaquah

The King County North SPAR project included the design and construction of an approximately 1 mile long four-lane road that connects the South SPAR project with the Sunset Interchange on Interstate 90. Geotechnical challenges included the evaluation of 50-foot deep soil cuts in unsuitable fill and native glacial soils, ground water issues, bedrock excavation, bridge foundations, mechanically stabilized earth (MSE) wall systems and reuse of excavated soils for fill in other areas of the project.

Subsurface exploration for abandoned underground coal mines near Roslyn, Washington

ICE has drilled several hundred borings into abandoned underground coal mines across the State of Washington. We normally use track-mounted drilling equipment to access these areas because of the difficult terrain. At this location on the Suncadia Resort project near Roslyn, the abandoned underground coal mine was found to be completely collapsed at a depth of approximately 170 feet below the ground surface.

NP2 Pond in the Issaquah Highlands Project

The NP2 Pond project involved the construction of a large stormwater detention pond with cuts up to 40 feet deep and fills up to 25 feet thick. The geotechnical aspects of the pond design required that the Washington State Department of Ecology Office of Dam Safety review and approve the design plans. The pond bottom was lined with a PVC material to prevent seepage into the subsurface.

Gravel Pit Reclamation

ICE provided the geotechnical design criteria for reclamation of the Bullfrog Gravel Pit near Roslyn, Washington. This site will be regraded along with permanent erosion control measures. Ultimately, the upland area will be used for a large hotel as part of the Suncadia Resort.

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