Water System Unidirectional Flushing Project

Unidirectional Flushing Project

What is UDF?

Unidirectional flushing (UDF) is an industry standard water system maintenance practice used to systematically scour, clean, and improve the carrying capacity of the water distribution system. Unidirectional refers to the fact that during the cleaning, water is only flowing in one direction. UDF involves strategically closing valves and opening specific hydrants to direct water through a designated pipe, while producing controlled scouring velocities to remove accumulated deposits. UDF must be implemented using a systematic plan in order to ensure safe and efficient flushing of the distribution system.

What will the UDF Project accomplish?

Public Works is seeking professional services to develop a UDF plan. The UDF plan is to include field journals in which identify locations and processes to implement flushing activities and meet minimum scour velocities while maintaining minimum system pressure during the flushing sequence.

The plan is to include field testing and data analysis to determine appropriate practices to protect aging piping, divide the network into flushing zones, define the prioritization and progression between these zones, and develop flushing sequences for each zone in the form of flushing field journals.

Why is the City doing the UDF Project?

Once the UDF plan is developed, Public Works will be able to implement a routine UDF program as an asset management/routine maintenance program serving as an effective method for cleaning and flushing out pipes, which greatly improves their capacity as well as the overall operation and longevity of the distribution system. More specifically, unidirectional flushing ensures that the system is flushed with clean source water and that high flushing velocities are achieved. This helps reduce sediment, biofilm, and corrosion products, which improves water quality as well as the overall operation of the water system and allows field crews to identify inoperable valves and hydrants.

The Public Works Dept. will issue an RFP for the UDF Project in November of 2023, a contract will be brought before City Council at the February 13, 2024 meeting for approval.