Marston Water Treatment Plant

Location: Denver, Colo.

Client: Denver Water

Completion Date: 2003

The Marston Finished Water Improvements Project in Denver, Colorado, was initiated to identify solutions to increase the finished water storage and conveyance capacity from the plant to 300-MGD. The water treatment plant has a complex finished water storage and conveyance system that has hydraulic constraints in the piping system between the Disinfection Contact Basin, Reservoir No. 3, the Ranger Box, and Reservoir No. 4. In addition, Reservoir No. 4 is unbaffled leading to concerns regarding the capability to maintain optimal water quality.

Burns & McDonnell, in association with Bates Engineering, performed a study to identify improvements to the finished water system which would correct the hydraulic and water quality concerns. A hydraulic computer model was created to identify and test possible piping solutions and a physical scale model of Reservoir No. 4 was used to test various baffling arrangements to optimize water quality.

Hydraulic Computer Model: A complex hydraulic computer model was used to identify improvements that would increase the hydraulic capacity of the finished water system. The computer model was developed and carefully calibrated against actual measured flow and headlosses as part of the study. The model identified larger connecting piping and new reservoir inlet and outlets which increased the usable storage from 2.5 to 8.9 million gallons.

Physical Scale Model: A physical scale model study of Reservoir No. 4 evaluated the need for adding baffles to the reservoir to promote mixing to optimize water quality. A model was constructed at the Bureau of Reclamation's Denver Hydraulics Lab. Sixty-five (65) dye flow tests were performed which revealed that with the anticipated flow rates through the reservoir the mixing would be adequate without the addition of expensive baffles.

The project was successfully completed in 2003 and the construction of the piping improvements are currently being completed.