New Kid's View

Could flooding answers lie in elementary physics?

Posted by Jerrianne Hayslett on Aug. 18, 2010 | 1 comment

flood, sewer, runoff

The South Milwaukee Common Council has approved spending $40,000 on two studies recommended by the city's Public Works & Public Property Committee related to the flooding and fouling of some South Milwaukee homes from last month's heavy rain.

Here is Alderman and PW/PP Committee Chair Erik Brooks's explanation of those studies as provided on his blog:

• One, to be done by Applied Technologies, would evaluate the sanitary sewer system at specific areas and make recommendations to reduce inflow and improve system capacity during big rains. The study, which is expected to cost just shy of $30,000 and take four to six months to complete, will specifically look at areas like Parkway Drive/Hemlock Court, Brookdale Drive and Blakewood Court.
• The second, to be done by R.A. Smith National, pertains more specifically to the 4th District. It would evaluate the stormwater system around the Parkway Heights area (the broader neighborhood around Parkway/Hemlock). This study is expected to cost around $12,000.

I had to rely on Alderman Brooks to provide that information because, although I attended, Monday night's PW/PP Committee meeting when the committee voted to recommend the studies, I didn't -- couldn't -- hear the motions or some of the committee's discussion, primarily because at least two of the aldermen spoke in such hushed tones, they were inaudible to the ten constituent spectators who cared enough and were interested enough to attend the meeting.

What I did hear, though, and another question raised at the previous PW/PP Committee meeting made me wonder about a couple of factors the city seems not to be taking into consideration.

One, related to what I managed to hear at Monday's PW/PP Committee meeting, is the size of the sewer pipes in the Parkway Drive area and when that system was installed. The pipes, if I understood the city official speaker, are 30 inches and 36 inches in diameter and the system was installed in about 1958.

If that's correct, wouldn't that account at least in part for the inability of the system to handle runoff due to heavy rainfalls such as those in April 2008 and the one last month? That would be because of the amount of residential and commercial development in the area in 1958 and the amount that exists now. In other words, how many houses existed in the Parkway area in 1958? The house I live in was built in the early 1960s and a couple of my neighbors who are the original owners of their houses, which were built a few years before mine, say Hemlock Court wasn't paved, Parkway Drive didn't even exist then and they were surrounded by empty fields.

How many businesses (if I heard correctly, those pipes come from non-Parkway areas and flow into the Parkway area, which possibly includes the commercial development on College Avenue between 16th Avenue and east toward Chicago)? How many driveways, sidewalks, parking lots, schools, playgrounds and other hard surfaces exist now in the areas that flow into Parkway compared to 1958?

The same questions could also be asked of the Brookdale Drive and Blakewood Court areas where homes were flooded and fouled.

What percentage of South Milwaukee is now paved over compared to the percentage of the city that was paved in 1958? Where does the water that can't be absorbed into the paved surfaces run off to? Where does the water go that's flushed and that runs down the drains of all the houses that a 50-year-old sewer system laid in a largely undeveloped area is now expected to serve?

My guess is that it backs up and overflows into basements and into what might be an equally inadequate and, I understand, leaky sanitary sewer system.

The second factor is related to the simple physics principle of displacement. If I fill a 10-inch by 10-inch dish that's 10 inches deep to the brim with water, what will happen if I put five inches of dirt in the bottom of that dish and pour in the same amount of water that filled it when it didn't have five inches of dirt in the bottom? I don't have to guess about this one. I know it will overflow.

I believe that is what has happened to Oak Creek, which flows just south of Parkway Drive and overflowed its banks and flooded the area in both April 2008 and again last month, and to the Mill Pond in Grant Park. Silt and debris does collect over the years in water ways and catch basins. I've seen all manner of trash and junk, including a bicycle, old computer parts and a full-size water heater in Oak Creek. And long-time South Milwaukee residents say they remember being able to swim in Mill Pond. It's so shallow now, it can be waded across and has a "sandbar" (more accurately, probably a sediment bar) in the middle.

Are there any records related to the depth of either Oak Creek or the Mill Pond or both? How deep were they 50 years ago? How deep are they now?

Have either Oak Creek or Mill Pond ever been dredged, I asked at last month's PW/PP Committee meeting.

Not the city's job, replied Alderwoman Lisa Pieper. That's county property. 

But it affects South Milwaukee residents, i.e. alderpersons' constituents. So why isn't the city talking to the county about getting both Oak Creek and the Mill Pond dredged?

Are there other water ways and/or catch basins in the Brookdale Drive and Blakewood Court areas that might be contributing to the flooding in those parts of the city?

Those are some questions that might have a bearing on the disasters that have afflicted so many South Milwaukeeans -- and perhaps the areas of Milwaukee that got flooded -- during recent years' of heavy rains and, according to climatologists, are becoming more common in coming years.