If you’ve been in downtown Granite Falls the past few days, no doubt you’ve see the disruption underway where the city has contractors replacing all of the utilities under Eighth Avenue between Prentice Street to Second Street. When you look at the large piles of dirt and the 15 to 18 foot deep excavation work that moves slowly westward, it isn’t hard to think of the word ‘mess”. Rightly so. It seems like a mess without getting to the edge of the excavation crater and seeing what is underway down in that hole. But “mess” isn’t really an accurate word. The project is a carefully planned and crafted replacement of some of the city’s most essential utilities, most of which are nearly a century old.
Those old utilities, like everything else, have a finite amount of usefulness. Although you can’t see them in their normal underground setting, the evidence was everywhere that the sewers were leaking, allowing ground water to infiltrate or seep into the sanitary sewer that serves the businesses along Eighth Avenue and connects to other sewer lines in the city. Those old sewers were usually constructed with clay tile pipe in short sections. The unsealed joints between those short sections of pipe allowed ground water to seep in. Equally problematic was the fact that clay tile itself is somewhat porous so that it allows groundwater to leak in as well. Even worse is the fact that those clay tile pipes are not strong to withstand time and the elements so because of shifting soils and boulders underground, they become cracked and broken or sometimes crumble from the saturated soil they have endured for decades.
Over time, those old clay tile sewers don’t flow like they are supposed to and they allow too much groundwater to seep in and flood the sewer treatment system. That forces the city crew to pump them discharging that water logged sewage into the lines that run to the river and that’s not supposed to happen. In short, old sewers need to be replaced. As the project on Eighth Avenue shows, doing that is complicated.
Sewers use gravity to deliver wastewater to collection points and to lift stations. That means that they often are buried deep and are often at the bottom of the trench that also has pressurized water mains seven feet below the surface but well above the sewer line. The water line may or may not be in need of repair or replacement but it has to be excavated to get down to the sewer line. That means both utilities have to get replaced.
On Eighth Avenue, things are even a bit more complicated. The intersection of Eighth Avenue and Second Street, near the Yellow Medicine County Government Center sits in what was once a small slough or wetland area. That wetland tends to reappear if there is enough rainfall so, many decades ago, the city installed a large storm sewer to drain that area and to direct any future heavy rainfall away and eastward toward the Minnesota River, just south of the footbridge.
Unfortunately, during flood events on the river, water backs up that pipe and bubbles up out of the inlets at the intersection of Eighth Avenue and Second Street and causes internal flooding. The city attempted to pump that water away during the big flood of 1997 but some damage was done to three houses and several businesses. Efforts during the 2001 flood were more successful when a pipe was laid on top of Eighth Avenue and across Prentice Street to the river. Traffic on Prentice Street was ramped up and over it, similar to what was done across Highway 212 near Seventh Street.
Eventually new pump stations were installed using the in-place storm sewers instead of a temporary above-ground pipe. The pump station for the Eighth Avenue pipe is located under a cover in the middle of Lende Plaza. Meanwhile, that old storm sewer pipe is still in place but, after all these years, it, too, is in poor condition and is also in the way for the sanitary sewer replacement. It was time to rebuild it all.
We all know that you can’t work under the surface of the street without disrupting the street and tearing up almost anything connected to it. The street, curb and sidewalks on Eighth Avenue had to be removed but will be rebuilt at the end of the project. A mess? Yes, it is. However, even with more than 12 inches of rain since August 1 in many rain gauges, the project is progressing despite all the challenges that wet weather brings.
Old sewers are a fact of life all around the United States. Almost every city in the country has old sewers and replacing them in a timely manner is something that has to be done. Unfortunately, that’s not always happening as it should. It’s hard for many federal and state politicians to get behind funding sewers. There is nothing to see after the project is completed. It’s out of sight, underground.
These projects are very expensive and that puts strain on cities and property owners. Still, property is worth a lot less if the sewers don’t work.
Granite Falls has done a lot of this work over the past 20 to 30 years but there is much more to do. This year’s project will also tackle problematic sewer connections under the concrete alleyway along the west bank of the river. That will be another mess to visit about in another column.
Meanwhile, as I write this on Saturday morning, we all wish for someone to stop the rain and let this fall be a dry one.