Since thestorm, many myths have circulated about what happened, what should havehappened to prevent basement backups and sewage overflow into local waterways,and what can be done in the future to prevent flooding and water damage.
Here aresome of the most prominent myths—and facts—about the flood, the role of theMilwaukee Metropolitan Sewerage District (MMSD) and how local governments,businesses and individuals can improve the area’s water management.
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Myth: The basement backups and sewage overflows are all MMSD’s fault.
Fact: MMSD is only one part of a carefully integrated system of public andprivate infrastructure. While MMSD owns 300 miles of pipes and the Deep Tunnel,the 28 municipalities in MMSD’s region own 3,000 miles of pipes, and individualproperty owners also own another 3,000 miles leading from their properties tothe local sewer line.
Beforefiguring out what happened during the July storm, it’s best to look at how thesystem works during a regular rainfall. During an average rainstorm, water goesinto a catch basin or storm drain and then flows into the municipally ownedsewer system (either a storm sewer or a combined sewer containing both stormwater and sanitary sewer water). If it’s in a separated sewer area, theuntreated storm water goes directly into a local waterway. If it’s in acombined sewer area, it goes to the metropolitan interceptor sewer, owned byMMSD, which leads to the Jones Island or South Shore water treatmentfacilities, where both the storm water and sanitary sewer water are treatedbefore being discharged. During heavier rainstorms, that water goes to the DeepTunnel, where it’s held until it can be treated. 
On the nightof the big July storm, a lot of that rainwater didn’t even make it to the MMSDpipelines.
Here’s whathappened during that storm: A lot of water was trying to enter the local sewersystem during a short period of time—for example, through the grates in thestreet. But the rainfall was so intense it couldn’t filter into the sewergrates fast enough, so it seeped into people’s homes—though the window wells orthrough leaky or cracked walls and floors. This water then drained through thebasement floor drain. When it did, it flowed to the sanitary sewer system, asif it was sewage. That storm water overloaded the sanitary sewer pipes that areowned by the individual and the local municipalities, and then backed up intobasements.
“There wereprobably a lot of instances in the last storm where there was so much flow so faston the local system that it never had a chance to get to our pipes because thelocal system couldn’t keep up and it backed up into people’s homes,” said BillGraffin, MMSD’s public information manager.
Not onlythat, but an overloaded pipe in one home can start a chain reaction and floodother homes on the block.
That’s whymany municipalities need to address the size and condition of their stormsewers to ensure that they can handle an intense storm. Because if heavyrainfall can get into the system in a decent amount of time, the water won’tback up into basements.
Myth: The Deep Tunnel failed on the storm of July 22-23.
Fact: The Deep Tunnel did not prevent an overflow during this very heavyrainfall, but the Deep Tunnel prevented a bad situation from becoming muchworse. During the big storm, which was so exceptional that it made national andinternational news, an estimated 30 billion to 80 billion gallons fell on theregion. MMSD can treat and store 1.1 billion gallons per day, which is more thanadequate for an average heavy rainstorm.
The DeepTunnel holds 521 million gallons of water in reserve, until it can be treated.In doing the math, the Deep Tunnel could never have held the amount of waterthat fell on the region in just a few hours.
So why do weneed the tunnel? Because without it, that half a billion gallons of untreatedwater would have flowed directly into Lake Michigan or flooded basements andstreets—and we would have between 50 and 60 overflows per year, as we hadbefore the Deep Tunnel was built.
“If the DeepTunnel had not been built, you would have had a massive overflow and the samenumber of—if not more—basement backups,” said MMSD Executive Director KevinShafer.
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Myth: We could eliminate overflows if we separated the combined sewers thatexist in parts of Milwaukeeand Shorewood.
Fact: Unfortunately, even sewer separation would not have preventedoverflows from the July storm. The mechanics of separation is complex andcannot be done on 11% of the combined sewers because they are located inDowntown Milwaukee and cannot be disturbed due to that location. Second, itwould cost an exorbitant amount—about $4.5 billion to $5.8 billion—to separatethe sewers and upgrade other features in the system, according to MMSD’scalculations. That estimate includes the cost to add 230 million gallons ofcapacity to the Deep Tunnel, add 300 million more gallons to the treatmentfacilities, add another 100 million gallons to tunnel pumping to relieve thetunnel, and then spend at the very least $2.7 billion to separate the sewers.That is a very conservative estimate, and even those additions may not preventoverflows and backups during intense storms. Finally, where sewers areseparated, all of the storm water that contains the oil, rubber from tires andanimal waste drains untreated into the waterways.
So the combination of combined sewers and the Deep Tunnelreduces pollution.
“The pollution would have been worse getting to the rivers thanwhat we had, because we were able to capture it [in the Deep Tunnel] and treatpart of that flow,” MMSD’s Shafer said.
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Myth: MMSD pumped untreated sewage into Lake Michigan.
Fact: MMSD has 150 points where untreated overflows are released. Only twoof those 150 points go directly into the lake. The rest of them flow into theregion’s three rivers—the Milwaukee, Menomoneeand Kinnickinnic rivers—which then flow into Lake Michigan.By the time it gets into the lake it’s sort of milky white, MMSD’s Graffinsaid, not some sort of a brown plume that looks like untreated, raw sewage.According to the state Department of Natural Resources (DNR), MMSD reportedreleasing 171 million gallons of untreated water from the sanitary sewer systeminto local waterways and 1.9 billion gallons of combined sewer overflows (a mixof storm water and sanitary sewer water, which is about 90% storm water and 10%sanitary sewer water). MMSD is allowed to have six combined sewer overflows peryear and averages about 2.6 overflows annually.
But MMSDwasn’t the only entity to have overflows. According to the DNR, 12 localmunicipalities in MMSD’s region reported sanitary sewer overflows as a resultof the July storm. Those municipalities are Milwaukee,Mequon, Brookfield,Cudahy, Wauwautosa, Muskego,Fox Point, Menomonee Falls, Shorewood, Brown Deer, Elm Grove and Whitefish Bay. South Milwaukee, which has its own treatmentfacility, also reported a sanitary sewer overflow.
Although thestate does not allow any of these municipalities to release sanitary seweroverflows into local waterways, Jim Fratrick, a watershed specialist at theDNR, said that none of these municipalities would be punished because all arein compliance with a 2005 order to upgrade their systems. None of their actionswas negligent, Fratrick said, which would be a reason for some sort of punitiveDNR action.
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Myth: That bad smell along the lakeshore is sewage that was releaseddirectly into the waterways.
Fact: That bad smell doesn’t seem to have anything to do with the overflows.Actually, it’s a problem with algae called cladophora,said Fratrick of the DNR, a recurring problem along the lakeshore.
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Myth: Milwaukee Mayor Tom Barrett promised that he’d shake up MMSD so thatthere would be no overflows and he hasn’t done anything.
Fact: Barrett commissioned an independent audit, which found that MMSD’smanagement of the system could not be faulted for overflows that resulted froma 19-day window of heavy rain in 2004. However, that audit did turn up problemswith infiltration and inflow in all of the communities in MMSD. Infiltrationand inflow problems include leaky pipes, downspouts that are connected to thesewer system, foundation drains in homes, and illegally hooked-up sump pumps.
MMSD hasidentified weak spots in the region and has allocated $1 million to themunicipalities so they can begin to repair those problems, and it is aiming toallocate $30 million over the next five years for further work.
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Myth: There’s nothing I can do as a concerned citizen about protecting theregion from flooding and overflows.
Fact: While these intense storms have been rare in the past, they’re goingto be regular occurrences in the future, experts say, the result of climatechange. These are going to be especially difficult to deal with in a highlydeveloped urban area like Milwaukee,since pavement, large-scale development and aging infrastructure make highvolumes of water difficult to absorb.
Fortunately,there are many strategies that individuals, businesses and local governmentscan implement to improve the region’s water management. But there’s an addedbenefit, too: These solutions consume far less energy than traditional sewagesystems use to pump and treat wastewater and storm water.
- Homeowners candisconnect their downspouts from the sewer lines and run them away from their homesand into their gardens or lawns. They can add rain barrels, which hold up to 55gallons of water that can be used for gardens and lawns when it isn’t raining.They can plant rain gardens or native plants, which improve water absorption.Owners of older homes with foundation drains can add a sump pump, which wouldremove water from their home.
- Businesses and somehomeowners can add green roofs, which reduce storm-water runoff, decrease abuilding’s energy consumption and improve air quality.
- Governments orlarge property owners can add more greenspace to their developments in the formof greenways, wetlands or bioswales. Porous pavement would allow water to draininto the ground below the pavement, instead of running into the sewer system.And more trees and plants located along roadways will enhance absorption ofstorm water.
