Below are some of our representative projects, sorted alphabetically.
- City of Lynnwood, Sewer Improvements Lift Stations #4 and #8
- City of Lynnwood, 204th Street SW Improvements
- City of Olympia, State Avenue Road Improvements
- City of Pacific, Stewart Road / Thornton Intersection Improvements
- City of Vancouver, I-205 Mill Plain
- Clearwood Community Association, On-Call Water System Repair and Improvement
- Helix Design Group, Mason County Public Works Facility
- San Juan County, Guardrail Improvements/Installation
- Summit Water and Supply Company On-Call Engineering Services
- Thurston County, Tilley Rd Maintenance Facility
City of Lynnwood,
Lift Stations #4 and #8
Skillings Connolly, Inc. provided design services for Sewer Improvements Related to Lift Stations No. 4 & 8. The project involved the upgrades of the existing sewer lines for increased flow capacity. The project consisted of two separate sewer conveyance systems: One from Lift Station No. 4 to 8, and the other the gravity portion of the sewer conveyance system from Lift Station No. 8 to 10.
City of Lynnwood,
204th Street SW Improvements
Skillings Connolly completed comprehensive alternatives analysis including a roundabout. This TIB-funded project reconstructed part of 204th and completes a missing section from 68th Avenue W to SR-99. We provided all PS&E to reconstruct and extend the roadway, modify utilities, and improve the stormwater drainage system. We designed the travel and bike lanes, curb, gutter, sidewalk, and illumination on each side. Analysis and design to reconstruct four affected intersections were also provided. The City’s utility infrastructure along 204th Street SW was expanded and retrofitted to accommodate the new design and the City’s growth.
City of Olympia, State Avenue Road Improvements
Skillings Connolly designed roadway and utility improvements to facilitate this redevelopment, which widened the existing roadways and provided safe routes for bicycles and pedestrians. As part of the alternatives analysis, we incorporated stop signs to facilitate the movement of oversized freight from the City’s busy Port area.
City of Pacific, Stewart Road / Thornton Intersection Improvements
Skillings Connolly prepared the PS&E to widen Stewart Road to 5-lanes with curb, gutter and sidewalks, improve intersections, add a new signal system, modify the state’s SR 167 ramp signal, upgrade the existing stormwater system to current standards, repair existing pavement, and add a new HMA overlay and acquire additional right-of-way. This project was funded through the Transportation Improvement Board and federal funds, meaning all work had to meet federal standards.
We provided transportation and roadway improvement engineering, as well as utility coordination. This included planning, preliminary and final design, and PS&E to widen the existing roadway, replacement of a 4″ AC water main with a 12″ ductile iron main, installation of a stormwater infiltration/conveyance system, construction of ADA-compliant sidewalks and ramps, and the associated curb, gutter, and sidewalk.
Coordination with Puget Sound Energy, Qwest, Comcast and the City’s sewer utility was necessary to ensure that all existing utilities were moved and/or adjusted adequately to negate conflicts with the new stormwater system and roadway geometrics. We also coordinated with the City’s environmental consultant regarding documentation and permitting, the City’s trail designer to accommodate the future Inter Urban Trail project adjacent to the new roadway, Gordon Trucking’s consultant who is designing the detention ponds for stormwater treatment and, to accommodate stormwater from an adjacent project that is being designed by another City consultant.
A critical aspect of this project was the need to surcharge all areas of new construction with as much as 4′ of material for six months to minimize post-construction settlement. This area of the City lies above a layer of peat that will compress under the additional weight of the new subgrade and surfacing, as well as the heavy truck loading experienced on this section of Stewart Road. Treating this issue correctly was critical to ensure that the new roadway didn’t settle to a point below the existing roadway to create a continuing maintenance issue. Additionally, to minimize the overall cost of the surcharge, a plan for disposal of the material was developed. The entire quantity was used for trench backfill or stockpiled on site for use on an adjacent future project.
City of Vancouver, I-205 Mill Plain
We began design for this new off-ramp and modifications to the existing on and off-ramps at I-205 Mill Plain Boulevard I/C using a 3D laser scanning survey system. A Leica HDS3000 was used to map the project site and roadway topography. The speed of data collection allowed our surveyors to collect the necessary information in a shorter period of time than with conventional survey equipment. The survey took place in close proximity to high-volume traffic which created safety concerns. The laser system offered improved worker safety, as well as significant time and money savings. The high degree of accuracy and short data collection time allowed design to begin ahead of the original schedule.
Geotechnical testing, analysis and design was used to support environmental documentation, surfacing design and structural design. Three reports were prepared to document the analysis, 1) a Geotechnical Report, 2) a Surfacing Report and 3) an Infiltration Report.
Once base mapping was complete, preliminary design was begun by developing horizontal and vertical alignments with lines, grades, sections and cut/fill lines, all to WSDOT and FHWA interstate highway design standards. Critical to this project was assurance that the adjacent and overlapping project would mesh correctly in the final condition. When completed, the two projects together will provide a braided ramp system with this project spanning over the future project. It was imperative that horizontal and vertical clearances and sight distances be set correctly to accommodate the future conditions. Geometric design was concluded with final design/PS&E.
The project footprint identified with the preliminary design effort allowed us to proceed with environmental documentation. This project required a NEPA Documented Categorical Exclusion and accompanying SEPA Determination of Non-Significance. Discipline studies were undertaken to address air quality and noise impacts, environmental justice and visual impacts. A local agency Environmental Classification Summary and Biological Assessment were also prepared to satisfy City, State and Federal requirements.
With receipt of traffic modeling provided by the Southwest Washington RTPO (RTC) via the City of Vancouver, we began operational analysis to determine appropriate lane configurations and intersection modifications. A new signal controlled intersection was designed to connect the NW Ramp extension with existing NE 112th Avenue. The new signal was interconnected with the N-E and W-N ramp termini at Mill Plain Boulevard and the signalized intersection at Mill Plain Boulevard and NE Chkalov Avenue. An intersection Plan for Approval was prepared and submitted to the City and WSDOT as was an Interchange Plan for Approval to document the I-205/Mill Plain Boulevard I/C modifications. Operational analysis and traffic design, signing, striping, illumination, construction staging/work zone traffic control was concluded with final design/PS&E.
Stormwater/hydraulics design was a major undertaking on this project. Two Threshold Discharge Areas (TDA’s) were involved with this project, the Columbia River to the south (only quality treatment required) and Burnt Bridge Creek to the north (both quality and quantity treatment required). Stormwater collection, conveyance and treatment were designed in accordance with WSDOT’s 2006 Highway Runoff Manual including the requirements for enhanced treatment. The topography combined with limited right-of-way required the use of a very large underground vault for quality treatment prior to the water being infiltrated into the underlying soils. Pre-treatment was provided prior to water entering the vault system. Stormwater/hydraulics design was concluded with final design/PS&E.
Two bridge structures were designed for this project, a single span bridge to cross the NW Ramp extension to NE 112th Avenue and a 6-span structure to take the W-N On-ramp from Mill Plain Boulevard across a future off-ramp the NE 18th Street and onto I-205. In addition, numerous retaining walls were required because of the limited right-of-way available and the close proximity of the existing on and off-ramps. One of the retaining walls was a soil-nail wall that allowed for more width beneath the Mill Plain Boulevard Bridge across I-205. The other calls were either conventional concrete cantilever walls or geotextile “bag” walls with concrete facings. Structural design was concluded with PS&E.
A public involvement effort was begun early in the project by preparing a Public Involvement Plan to chart the planned activities throughout the life of the project. Open houses, post card announcements and newsletters were used to impart information to the public and request/receive feedback on the project. Design visualization graphics were prepared for presentation and a public contact database was developed to track telephone and email contacts and the resulting feedback.
Clearwood Community Association, On-Call Water System Repair and Improvement
Clearwood Community operates and maintains a water system serving 1,350 customers. We have provided them with a variety of engineering services such as surveying and design for the replacement of 4,700 lineal feet of six-inch water main with eight-inch service lines on narrow, rolling residential streets with steep grades. The project included preparation of plans, profile, and detail sheets, as well as cost estimates, specifications, and coordination with the homeowner’s association. Bidding support and post-construction record documents were also provided. Our design required careful coordination with Puget Sound Energy as the water main and new underground electrical transmission lines were constructed simultaneously. The water system construction was designed to be installed in sections to minimize shut down periods for homeowners when the new water main was brought on-line. The design also included installation of new Air-Vac assemblies meter setters with PRVs and hydrants.
Other assignments have included comprehensive planning, design, and commissioning of a new 450 gpm well, a 400,000-gallon reservoir, and water main extensions. We have also performed design, construction, and commissioning of the system’s water pH adjustment facilities, which treats the water with a 25% solution of sodium hydroxide.
Helix Design Group,
Mason County Public Works Facility
We prepared final PS&E for the site development which included drainage, septic, and water reports in conjunction with the SEPA documentation; gathered existing record data along with survey work for compilation of a base map; and provided engineering of water system, site septic system, drainage, erosion control, grading, paving, and access roads. Skillings Connolly coordinated with utility companies and gained approval from the Department of Health for the water system. The water system included a new well, a 200,000 gallon storage tank, fire pump, distribution piping, and fire suppression.
San Juan County,
Skillings Connolly prepared PS&E and provided construction management for guardrail improvements at eight locations on Orcas and San Juan Islands. To complete this project, we obtained mapping from the County and added utility locates and additional data by our survey crew. We also calculated the length of need for County-prioritized areas warranting guardrails. Exact lengths of guardrail, post lengths and types of terminal treatment were identified for each site. We also provided construction management, which included locating a construction inspector temporarily to Orcas and San Juan Islands.
Summit Water and Supply Company On-Call Engineering Services ǀ Sumner, WA
Summit Water & Supply Company (Summit) serves about 15,000 people in central Pierce County. As engineer of record for this public water system, Skillings Connolly prepared comprehensive plans, specifications and designs, water demand forecasts, and water rights applications. We also evaluated regional supply options and possible implementation strategies, conducted cost of service and other financial studies, developed proposed water rates and fees, and designed water treatment facilities for disinfection and corrosion control.
First, a 5000 gpm pumping station was developed to meet build-out demands. At the client’s request, Skillings Connolly developed a design for a 2500 gpm pump station as an initial capacity. This station was configured to consist of two Goulds with 1750 gpm, 75 hp VFD vertical turbine pumps, with allowance for a third pump by installing a spare “can” for future use. The tank fill and discharge are controlled by Summit’s Supervisory Control and Data Acquisition (SCADA) system, which allows the tank to operate as an additional source for the system during peak periods. Valves with electronic control interface coupled with the pump’s VFD controllers provide a set flow rate while maintaining back pressure and altitude control. Skillings Connolly supervised construction and startup of these facilities. We also recently undertook a rate study which included a cost of service and other financial studies, which was used to develop a water rate structure with associated fee schedule
Tilley Rd Maintenance Facility
Thurston County expanded their public works maintenance facility located on a 44-acre site west of Tilley Road (SR 121). As a subconsultant to KMB Design Groups, Inc., Skillings Connolly worked on the master plan as well as the PS&E for site development.
This LEED Gold candidate project included parking lots and a new office building, maintenance shop, Emergency Operations Center (EOC), fueling station, plaza, fountain, and a 9000 square-foot stormwater pond. Our site design also included other stormwater innovations such as permeable paving, a demonstration rain garden, and diverted roof runoff, which is collected in several 10,000-gallon storage tanks to provide irrigation water. We prepared drainage, septic, and water reports in conjunction with the SEPA documentation; gathered existing record data and provided the survey work for the compilation of a base map; performed a Level 1 Traffic Impact Analysis (TIA) and a Level of Service Analysis (LOS); and provided engineering of a large onsite septic system; water system for domestic use, fire flow, and re-use; drainage collection, conveyance, treatment, and disposal; erosion control, grading, paving, and access roads. In addition, we coordinated with utility companies and received approval from the Department of Health for the Class “A” Water System Report. The water system design included a new well, domestic booster pump system, distribution piping, and expansion of the site’s fire suppression capabilities. Skillings Connolly also provided services in connection with WSDOT approval of new accesses and frontage improvements to the state highway. This included preparation of a PFA and detailed construction plans for the necessary upgrades to the highway.