Service Area Utility Plan

Metro Wastewater Reclamation District, 
Colorado

Service Area Utility Plan

Project Highlights: 
  • Evaluation of the capacity and condition of MWRD’s collection system to handle service area flows and loads.
  • Distribution system modeling.
  • Improvement recommendations for MWRD’s Transmission Division’s inspection and maintenance program.
  • Guided by the cMOM regulations.

The Metro Wastewater Reclamation District (MWRD) retained Carollo to complete a Service Area Utility Plan. This plan addresses the current hydraulic capacity of the transmission system, including impacts of infiltration and inflow, and examines its ability to provide adequate service in the future. The work effort determines demographic trends within MWRD’s service area so that wastewater flows conveyed to the MWRD’s Central Treatment Plant can be estimated. Part of this process includes estimating and examining long-range population and land use trends.

MWRD’s transmission system includes 43 gravity interceptor sewers, four lift stations, and four force mains. This system consists of approximately 236 miles of sewer pipe ranging in size from 8 inches to 90 inches in diameter, 65 primary metering facilities, 41 diversion structures, and approximately 3,750 manholes. Much of the transmission system was constructed within the last 15 to 20 years.

The project involves reviewing and recommending improvements to MWRD’s Transmission Division’s inspection and maintenance program. Work includes developing a comprehensive real-time InfoWorks model of the distribution system, maintainable by MWRD staff. Key features of this model are:

  • A GIS-based land-use and population projection model.
  • A flow-and-load-based model.
  • A hydraulic model of the collection system.
  • A predictive corrosion model.

The Service Area Utility PlanThe Service Area Utility Plan for the Metro Wastewater Reclamation District addresses 43 gravity interceptor sewers, four lift stations, four force mains, 65 primary metering facilities, 41 diversion structures, and approximately 3,750 manholes.

The model’s purpose is to evaluate the capacity and condition of the collection system to handle service area flows and loads. Project tasks have included the evaluation of several hydraulic models (with the final selection of InfoWorks) and development of a GIS-based data storage system using ArcView. Additional tasks include evaluating the current inspection models and conducting a condition assessment of the entire collection system as part of a sanitary sewer overflow (SSO) elimination program with the Colorado Department of Public Health and Environment (CDPHE).

The review of inspection and system condition will ultimately be guided by the capacity, management, operations, and management (cMOM) regulations. Final products will include the utility plan report, a capital improvement plan, a comprehensive service area model with the four model components listed, and an inspection and condition evaluation.