Multi-Million Dollar Raw Water Main Project Still on the Table

The Glasgow City Council continues to explore options to replace the nearly eight-mile-long raw water transmission main supplying the precious resource to municipal customers.

As the water main connecting the Missouri River with the city of Glasgow's water treatment plant continues to erode, the city may face costly spot repairs to keep the system running, engineers say.

The current 20" main - stretching 7.8 miles to a valve vault Southeast of town - was installed in 1987, and has experienced seven leaks since 2003, according to Jeff Ashley, Morrison Maierle senior process engineer. Morrison Maierle is a consulting firm which provides infrastructure planning for city, county and state governments throughout the Pacific Northwest.

During their regular meeting June 7, councilmembers unanimously approved Resolutions 3065 and 3066, accepting a Morrison Maierle study about potential paths forward and to allow the firm to submit applications for federal and state funding for the potential project.

"A really good question is how is this going to be funded?" Ashley said. There are "two different funding scenarios for the city to consider, and this is where the application of rural development comes into play."

Options include taking no action, replacing the piping in phases or completing the project all at once.

"As you may expect, it is less expensive to do it all at once, just like if you are building a house you are piece mealing it year by year it takes longer," Ashley said.

If the city decides to replace the piping, municipal water customers are expected to see rate hikes ranging from $12 to $18 a month on their monthly bills, Ashley noted.

CURRENT SYSTEM

The piping now in place consists of a steel cylinder with a concrete core, wrapped in prestressed wire, and coated with mortar. While in common use in the late 1980s, the materials are considered obsolete as they are prone to serious corrosion in wet environments, Ashley has said.

This has led to seven leaks in the system over the past 18 years, which can be costly to repair due to the availability of materials and a construction company with the resources to tackle such projects on the fly.

One such leak happened at one of several places where the main crosses the Milk River as it snakes into Glasgow. Due to contemporary regulations, replacing the impacted section was no small ordeal, since it could not be done in a similar manner to how the pipe was first installed in 1987, Ashley said.

However, in the case of catastrophic failure, the water system could be out of commission for days or even weeks, Ashley said.

With such a contingency possible, now may be an appropriate time to look into replacing the entirety of the pipeline with new piping made of PVC, which is more corrosion resistant, Ashley has said.

CURRENT OPTIONS

During the regular city council meeting May 1, Ashley gave a public briefing about the issue, and outlined three alternatives for the city to consider. The first would be to simply opt out and spot repair the current line as needed. The second would be to replace the line in four phases over the next eight years. The third would be to replace the entirety of the line in one project - beginning in 2023 and spanning through 2024.

There are pros and cons to each plan, Ashley has said.

Phase one of the second option would begin with replacing the locations where the pipeline crosses the Milk River, minus the crossing already replaced. The pipes cross under about 15 feet below the river bed. In the 1980s, construction crew simply dug out a channel, placed the piping and refilled the channel.

Such methods are no longer feasible due to governing regulations. Now, piping is pulled in from side to side and connected to existing pipelines after flowing through a butterfly valve.

• Phase 1 construction would begin and end in 2022, Ashley said. It would cost about $2.58 million total, including engineering and administrative fees.

• Phase 2 construction would begin in 2024 at an estimated total of $3.8 million.

• Phase 3 construction would begin in 2026 at an estimated total of $3.82 million.

• Phase 4 construction would begin in 2028 at an estimated total of $2.1 million.

Altogether, the phased projects would cost about $12.3 million with engineering, construction, administration and other fees.

While a higher long-term cost than an all-at-once project, a phased approach would likely be more apt to be approved for loans, Ashley said.

Chris McDaniel can be reached at 406-228-9301 or via email at [email protected].