MMSD hiring firm to study overflows
The Milwaukee Metropolitan Sewerage District will hire an engineering consulting company to recommend improvements to a regional sewer system on the northeast side of Milwaukee County that has been identified as the cause of six sanitary sewer overflows during heavy rainstorms since 2008, under a contract awarded Monday by the district’s commission.
The commission agreed to pay Brown and Caldwell up to $939,677 over five years to evaluate the capacity and flow constraints within the regional sewer system, known as the North Shore metropolitan interceptor sewer, and identify upgrades to the system that would prevent additional overflows.
The system collects municipal flows from a 30-square-mile area that extends from E. Fairmount Ave. on the south to County Line Road on the north, and from Lake Michigan west to N. 27th St., according to Karen Sands, MMSD planning, research and sustainability director.
The largest pipe in the North Shore system, a 72inch diameter interceptor sewer along W. Green Tree Road, has been identified as “the main cause” of separate sewer overflows on the northeast side of the district’s service area, Sands said.
Six sanitary sewer overflows occurred at a W. Green Tree Road discharge pipe to the Milwaukee River between 2008 and 2015, according to records. The dates and volumes of untreated wastewater overflows: June 7 to 9, 2008 — 53.4 million gallons; April 26, 2009 — 624,000 gallons; July 15, 2010 — 14 million gallons; July 22 to 24, 2010 — 24.1 million gallons; June 18, 2014 — 140,000 gallons; April 9, 2015 — 1.67 million gallons.
Flow and capacity restrictions in the 72-inch interceptor sewer in the April 9, 2015, storm also increased the severity of a separate sanitary sewer overflow that day in a different part of the North Shore regional system, according to MMSD senior project manager Cari Roper. About 360,000 gallons of untreated wastewater were discharged that day into a ditch and wetland in the 400 block of E. Brown Deer Road in Bayside.
Overflows of separate sanitary sewers are not permitted under a state permit except in conditions, such as reducing the risk of sewage backups into basements.
In the April 9 storm last year, record rainfall of 3.18 inches for that date was measured at Mitchell International Airport and an MMSD gauge on the north side measured 3.51 inches.
Rain entering municipal sanitary sewers from leaking residential laterals and other connections can overwhelm the capacity of the interceptor sewer, and those excessive loads slow the flows in the regional system, according to a report provided to the district’s commission. The risk of basement backups and property damage increases when flows stop in the larger regional pipes.
Valley site for sale
In other action Monday, the commission agreed to list a Menomonee Valley property for sale with an asking price of $1.3 million. The 1.5acre parcel on the Menomonee River at S. 25th and W. Canal streets is no longer needed by the district, officials said.
The riverfront parcel includes a 13,500-squarefoot garage with 19 overhead doors and office space, as well as parking lot and fueling station with three underground storage tanks.
The property is zoned industrial and offers access to I-94 and downtown Milwaukee, according to a data sheet. It is a few blocks west of the Potawatomi Hotel & Casino.
The district built the garage in 1987 for fleet vehicle repair, after completing construction of the crosstown, or west, leg of the deep tunnel system in 1986.
The tunnel extends beneath the property around 300 feet below the surface. A wastewater drop shaft to the tunnel is located on the property but is not included in the sale.
The City of Milwaukee began leasing the property in 2003 for maintenance of its parking enforcement fleet. The city is seeking a different location for that work.
Also Monday, the commission re-elected John Hermes as chairman and Kris Martinsek as vice chair for 2017.
Hermes, a former Greendale village president and trustee, is principal of John Hermes Consulting, specializing in government relations and economic development advising.
As chairman, he will be paid $12,370 in 2016.
Martinsek, of Milwaukee, is principal and owner of Martinsek & Associates, a public relations and marketing consulting firm.
The vice chair and other MMSD commissioners are paid $10,683 a year.
The Milwaukee mayor appoints seven of 11 commissioners. The Executive Council of the Intergovernmental Cooperation Council, made up of elected officials representing Milwaukee County suburbs, appoints the remaining four commissioners.