Town of Winthrop, Washington
General Sewer Plan Update
NPDES Permit No. WA-002088-5
The Town of Winthrop, Washington is currently updating its General Sewer Plan. The Town’s vision for the General Sewer Plan is a readily accessible and easy to understand infrastructure plan based on the Town’s land use planning assumptions, seasonal tourist impacts, contracted capacity to Sun Mountain Resort and inflow and infiltration (I&I). The plan will provide a road map for future expansion of the wastewater systems to the serve the Town over the 20-year planning period. It will also set forth a clear framework for forecasting, scoping and prioritizing future capital and restoration and replacement (R&R) project needs.
Planning Process - WAC 173-240-020 (7)(f)
The "general sewer plan" is a comprehensive plan for a system of sewers adopted by a local government entity. The plan includes the items specified in each respective statute. It includes the general location and description of treatment and disposal facilities, trunk and interceptor sewers, pumping stations, monitoring and control facilities, local service areas and a general description of the collection system to serve those areas. The plan also includes preliminary engineering in adequate detail to assure technical feasibility, provides for the method of distributing the cost and expense of the sewer system, and indicates the financial feasibility of plan implementation.
The General Sewer Plan will consider any available technical data, along with customer values and necessary policy decisions to create a 20-year infrastructure investment plan. It will include a summary report of the general location, condition, demand, capacity, and description of all collection facilities, including wastewater pipelines, pump stations, monitoring and control facilities. Engineering analysis will be conducted to assure technical feasibility and expansion of the wastewater system in a logical, cost-effective manner.
Key Outcomes
As part of the planning process, the Town aims to accomplish the following key tasks:
- Establish Unit Flow Values (flow per person, employee, Accessory Dwelling Unit (ADU) and Hotel/Motel/Restaurant) based upon historical data and recent water consumption data trends
- Evaluate capacity of the collection, river siphon and lagoon treatment system
- Forecast sewer capacity needs for the next 20 years
- Develop long-term financial infrastructure plans to provide services
- Forecast future Capital Improvement Plan (CIP) and R&R investments
- Identify sources of funding to implement the CIP and R&R
- Engage Town Council and other community stake holders and provide meaningful input opportunities
- Assistance Preparing NPDES Permit Application due July 2019
- *Financial modeling of rates and charges (as budget allows)
Schedule
Request for Qualifications Due – (3) three O’clock PST, February 11, 2019
Selection Process (possible interviews) – March 4 – 8, 2019
Scope and Contract Negotiated/Notice to Proceed – March 22, 2019
Engineering Analysis, modelling and capacity assessment – May 2019
Asset Management Plan, methodology for prioritizing restoration and replacement projects with consideration for integrated upgrades to gravity sewers, pump stations and treatment lagoons – June 2019
Complete renewal application for NPDES Permit – July 2019
Capital Improvement Plan identifying existing infrastructure and future needs. Develop a CFP, including 20-year cost estimates with consideration for the ultimate build-out scenario consistent with the Town’s Comprehensive Plan – August 2019
Draft Report – Ecology Review – SEPA – Comment Period – Public Hearing – Adoption Oct/November 2019
Final Report – December 2019
