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Sewer Screws web

What’s Going On Down There?

Story and photo by Vince Bushell

Many of us are dealing with construction in Riverwest. We became used to Locust Street being closed. You could actually walk across Locust Street without fear of death by auto. The cars are back on Locust Street but the construction goes on.

All winter long they have been digging and then burying and digging some more. Deep holes that look like they are close to 20 feet deep. A chasm was dug on Weil Street by Nessun Dorma, which seemed to be there forever this winter. Finally the hole is filled, but barricades still block part of the sidewalk. Hey, Riverwesters, get over there and have a beer and a meal at Nessun Dorma. I am sure this construction has hurt their business some. I also heard some complaints about Locust Street and impact on businesses there. TV news was waxing about the impact on commerce as well. Complaining is easy, understanding what is going on is more complex.

I saw city workers paint lines down my street, 2800 block of Bremen. That is a sure sign they are going to dig it up. I started to watch a little closer to what was going on. I took some photos and drew the attention of a foreman for one of the contractors. He seemed nervous about bad press. I assured him I am pro sewer fixing. However, what he said they were doing caught my attention. I called City Hall and talked with an engineer Tim Thur, who had all the information I wanted. So now I know. And you will too if you pay attention.

Everything you wanted to know about sewers, and more

Storm sewers catch rain off the street and any water that flows onto the street and carry it away. Where the water goes is a big part of the story. Sanitary Sewers carry fecal material and anything else that we citizens flush down the toilet. They also carry rainwater from our roofs that are still connected to the sewer line from you home. The other option for run off from the roof is rain barrels and better yet rain gardens.

Then we have something called Combined Sewers in Milwaukee. Which combine both the rainwater runoff from the street and all the sanitary water as well. Industry also sends wastewater into the combined system.

In Milwaukee, in Riverwest, we have Combined Sewers. What they are installing on some streets in Riverwest is a separate storm sewer (only rain and whatever else is on the street. That makes the existing sewer line a separate Sanitary Sewer system (toilets and whatever else you put down a drain, and connected downspouts from your roof). However once they reach the big pipe running under Humboldt Blvd., it is all combined again as it eventually runs down to Jones Island where all the water is treated before being released into the harbor

Pipes, big ones, small ones, old ones, new ones

The bigger the pipe the more water and waste it can carry. You start with the laterals that run from your house to the street sewer line. The street sewer line joins a larger sewer pipe that, in my case, joins an even larger deeper pipe running down Humboldt blvd. And so it goes, Gravity is the force that carries the water all the way down to near lake level at Jones Island. Jones Island is across the river from Summerfest, if you didn’t know. These pipes are owned by the municipalities, in our case the City of Milwaukee. The Metropolitan Milwaukee Sewerage District (MMSD) is responsible for supervising treatment at Jones Island and for the biggest deepest pipe of all, the Deep Tunnel.  More on that online, if you are interested see link at end of story.

The sewer pipes we have in parts of Riverwest were not adequate to carry all the storm water during big rain events, and most likely allowed water to seep into the pipe at points which diminished the pipes capacity during big rains. The plan is to replace the collector pipes that run east and west with larger pipes and connect them to a new storm water pipe running north and south. The old north south combined pipe now a sanitary pipe with less flow remains in place. One problem was there was no room under the street along Hadley to install the sewer drilling  machine larger sewer pipe. There is a large fresh water supply pipe running down Hadley (remember, keep the drinking water supply separate from the sewer pipes). The solution was to dig a new east west tunnel under the sidewalks. You see large screw like drills and large steel carrying pipe lined up along the street. The contractor digs a shaft to the needed depth and then drills horizontally (block by block) the channel under the sidewalk. The steel carrier pipe is pushed down the tunnel to the next corner (in this case Weil Street). The carrier pipe is fitted with concrete pipe and the space between the steel carrier pipes is caulked in place. The predicted result is greater capacity for handling water during storm events and less street flooding. And less infiltration of groundwater into the sewer system.

A new north-south concrete line is dug the old fashioned way near the middle of the street. The pipes that run across the street from the curb sewer with grates are connected to this new storm water pipe laid down the north south streets, like mine, Bremen Street (2800 Block).

Got that? It is impressive to see how fast the contractor can dig up the street lay the pipe and bury it. They finished the whole block in a little more than a day and then made the connections to the “storm drains” (the grate at curbside with vertical connection to storm sewer pipe) and the carrier pipe running down Hadley Street.

Cost benefit of the large carrier pipe running down Hadley

It may have been less expensive to dig up the sidewalks for this new east-west carrier pipe down Hadley St. How do you measure the inconvenience of digging up the sidewalks (and killing all the street trees)?

In some future time, we may be able to design a system that uses these separate rainwater pipes to go directly into the river during large rain events, but keep processing the rainwater during normal rain events. The goal of the MMSD is to stop overflows of combined sewer water into our rivers, streams, and lake.

Rainwater may be clean as it falls but our streets are far from clean and bacteria from animals mixing with leaves and other organic material creates a biological problem that can result in polluted rivers and streams. You can: Put dog poop in a bag into the trash. Compost leaves if you can or rake them for pick up by the City in the fall. In sum overflows from the combined sewers is not good, should be minimized, and eliminated as a goal. Treating the rainwater that does end up on the streets during normal sewer treatment operation can result in cleaner rivers and lake because the water coming off the streets is not clean.What about the old pipes?

Another method repairs sanitary and combined sewer pipe in place.  This is also being done as part of the project of sewer improvement. Several years back the large sewer tunnel under Humboldt Blvd. was repaired in place. The method is called CIP or Cured In Place.

Large or small sewer pipe can be repaired with this method. A plastic sleeve is pulled through the pipe to be repaired and then inflated with steam. This chemically activates the liner that hardens and creates a smooth non-leaking “good as new” pipe. The determination of the method to use is dependent on the flow requirements and the general conditions of the system and goals for the system.

For a history of Milwaukee’s sewer system and deep tunnel project. Visit Urban Milwaukee

MMSD History – Urban Milwaukee.com

This is an excellent history of the important infrastructure that helps keep our river and lake waters clean.