Water Environment Services

• Owner – Clackamas Water Environment Services
• Design Engineer – Carollo Engineers
• Construction Manager – AKS

System Overview

Clackamas Area Interceptor Improvements Project (CAIIP) includes 5 miles of pipe and capacity upgrades which are needed at varying timeframes

Map showing the path of the entire interceptor project

Middle Interceptor Project Overview

• Approximately 12,400 linear feet of 42-inch to 48-inch fiberglass reinforced polymer mortar pipe (FRPMP)
• Project will have Fiberglass manholes
• Two sliplining segments (approx. 1,200 linear feet total)

Map showing the Middle Interceptor route, primarily down Highway 212

Two Force Main Connection Locations

Camp Withycombe connection

• New 4" and 15" PVC SDR35, 14" C900 PVC piping
• Abandonment of the existing Withycombe Pump Station

Diagram of the force main connection near Camp Withycombe

Clackamas Industrial Area

• 90 linear feet of 10" C900 PVC pipe

Diagram of the force main connection for the Clackamas Industrial Area

Highway 212 Traffic Control Requirements

• Approximately 9,200 linear feet of alignment within Highway 212 in ODOT Right of Way
• Alignment located in southernmost travel lane (eastbound travel lane)
• Days/Hours Allowed to Work: 8:00 PM to 5:00 AM each night (7 days a week). All lanes must be open from 5:00 AM to 8:00 PM.
• Minimum Lanes Open: Eastbound traffic reduced to one lane

Diagram illustrating two-lane and median closure

Diagram illustrating two-lane and median closure

Property Owner Coordination

• North Clackamas School District: Work must occur between July 1 and August 31
• Camp Withycombe: No work on Saturdays, Sundays, or federal holidays
• Fred Meyer: One departure lane and one inbound lane must always be open

Bids will be based on this information; Contractor can negotiate other arrangements with individual property owners once under contract

Entrance to Fred Meyer

Map showing locations of Camp Withycombe, North Clackamas School District, and Fred Meyer

Permitting

• WES in process of obtaining ODOT Utility Permit
• WES to apply for Clackamas County Utility Permit
• Additional permits needed (from the Contractor):
• Clackamas County Grading Permit
• Clackamas County Right of Way Permits (road closures)

Dewatering

Geotechnical Data Report in Appendix includes groundwater information

• Exploration ID  >  B-052
• Top of Borehole Elevation (feet) > 115.0
• Date of Groundwater Minimums and Maximums > 10/10/2023, 10/28/2023
• Depth of Groundwater (feet below ground surface) > 10.6, 9.1
• Elevation of Groundwater (feet) > 104.4, 105.9

Approximate depth of trench: 14' - 28'

Abandonment, Lateral Connections, & Bypass Pumping

• Approximately 2,300 linear feet of alignment is removed and replaced, 10,100 linear feet of alignment is installed parallel and abandoned existing interceptor.
• Existing service connections to interceptor to be reconnected or extended
• Anticipated flows in existing interceptor:
  • Dry Weather: 3.0 million gallons per day
  • Wet Weather: 10.0 million gallons per day

Diagram illustrating new interceptor and existing interceptor to be abandoned

Required Qualifications

• Bidder's proposed superintendent has supervised construction of at least 1 mile of 36-inch diameter or larger circular pipe sewer pipe in the last 10 years.
• The Bidder's proposed superintendent has supervised construction of at least one project with not less than 500 linear feet of fiberglass reinforced polymer mortar pipe.
• The Bidder has constructed at least one pipeline project with a total construction cost of $10,000,000 or more in the last 10 years or performed as a sub-contractor with a sub-contract cost of at least $10,000,000. To be considered a pipeline project, the pipeline construction cost must be at least half of the total construction cost.

Bidding Information

• Anticipated date of advertisement: May 2026
• Engineer's Estimate: $26.8 Million
• Project receiving State Revolving Fund funds
• No mandatory pre-bid conference, optional pre-bid conference to be held

Definition and Purpose of System Development Charges

System Development Charges (SDCs) are one-time fees charged to new developments or changes to existing developments that increase demand, i.e., the use of a public wastewater and/or surface water system. SDCs provide dedicated funding for capacity-enhancing capital projects to ensure that new developments and changes in use contribute their fair share toward the costs of expanding and upgrading WES’ infrastructure. The charges are solely used to fund WES’ capital improvements or qualifying debt service payments.

Statutory Framework

SDCs are governed by Oregon state law (ORS 223.297-223.314). These statutes provide a uniform framework that ensures charges are assessed in a fair and equitable manner, and used solely for capital improvements.

State statutes specify the guidelines for calculating and modifying SDCs that WES and other organizations must follow, as well as accounting requirements for tracking revenues.
Components of SDCs

SDCs generally consist of the following components:

1. A Reimbursement Fee component recovers the costs for existing infrastructure that has available capacity to serve new development.
2. An Improvement Fee component funds planned capital improvements that will increase system capacity to meet future demands.
3. Compliance Costs are authorized by ORS and intended to cover the costs of developing the SDC methodology and required annual accounting.
   Calculation

The calculation of SDCs involves the following steps:

1. Determine Capacity Needs: Assess current system capacity and project future demands based on anticipated growth. Growth projections are based on the most recent population study for WES’ service area.
2. Develop Cost Basis: Estimate the costs of existing and planned infrastructure necessary to provide new capacity.
3. Determine Unit Charge: Calculate the unit charge by dividing the cost basis by the existing and/or future units of capacity. The calculated unit charge represents the maximum allowable charge and a reduced SDC amount may be adopted by a governing body.

Reimbursement Fee (Eligible value of existing facilities ÷ Existing and future units served) + Improvement Fee (Eligible cost of planned capacity-increasing capital projects ÷ Future units served) + Compliance Costs = 
System Development Charge ($ per unit of capacity, EDU or ESU) 

WES’ SDC methodology expresses existing and future system capacity in terms of Equivalent Dwelling Units (EDUs) for wastewater, and Equivalent Service Units (ESUs) for surface water. EDUs and ESUs are units of measurement assumed to be equivalent to the usage of an average single-family residential dwelling unit (EDUs) or parcel (ESUs), as determined by WES Rules and Regulations.

Application of SDCs

SDCs are assessed to new development, or changes in development that increase system demand, based on the type of development and its estimated impact to the system:

• Wastewater EDUs are assigned to single-family residential development based on the square footage of the living area as an indicator for projected system demand. EDUs are assigned to non-residential development based on demand factors that are specific to the class of service.
• Surface Water ESUs are assigned to development based on the square footage of impervious surface area for non-residential, multi-family, and attached SFR properties; detached SFR properties are assigned a single ESU.

WES’ Rules and Regulations contain tables that specify the EDU and ESU assignments for each type and class of development.

Collection Timing

For developments in Happy Valley and unincorporated areas within Rate Zone 2, SDCs are typically collected at the time a building permit is issued. For wholesale city customers served by WES, SDCs are collected as part of each city’s permitting process. The collected fees are then remitted to WES in accordance with the terms outlined in the Intergovernmental Agreements between WES and the respective cities.

Use of SDC Revenues

State statutes authorize the expenditure of SDCs revenues for the following:

Improvement fee revenues may only be spent on capital expenditures that increase system capacity, including:

• Expanding and/or upgrading wastewater treatment and collection facilities
• Expanding and/or upgrading surface water management infrastructure
• Principal and interest payments on debt that was used to pay for capacity-increasing capital improvements

Reimbursement fee revenues may be spent on any capital expenditures associated with the system for which the fees are assessed, including principal and interest on related debt.

An annual accounting of SDC revenues, including the total amount collected and the amount spent on each project funded by SDC revenues, is required by statute. WES accounts for wastewater and surface water SDC revenues and expenditures in dedicated funds to ensure compliance and transparency. WES’ Rules and Regulations further require that revenues from reimbursement fees and improvement fees are tracked separately.

Establishment and Modification of SDCs

SDCs must be established or modified by an ordinance or resolution of WES’ governing body:

• SDC Methodology updates require adoption by the governing body at a public hearing, 90 day’s advance written notice to the list of persons requesting notice, and that the methodology is available for review at least 60 days prior to first hearing.
• SDC modifications may be made without changing the methodology if those modifications involve either indexing the SDC for inflation, or updating the capital project list or population projections that the SDC calculation is based on.

WES’ SDC charges are generally indexed annually, in conjunction with the budget process, and based on the Engineering News Record Construction Cost Index.

Additional Resources

WES’ Current SDC Rates and FAQ

WES Rules & Regulations