Water Reuse Handbook - the Public Building Commission of Chicago

Water Reuse Handbook
Introduction: Benefits of Water Reuse
Benefits of Water Reuse
Introduction
2 : Public Building Commission of Chicago
The City of Chicago was founded, in large part, due to its location at
the junction of the Chicago River and Lake Michigan, as well as at
the convergence of the Mississippi River and Great Lakes watersheds.
It promised superior transportation, enhanced trade opportunities,
and ease of access for visitors. Nearly 20 percent of the earth’s and
95 percent of the nation’s fresh water supply is found in the Great
Lakes. While the region’s fresh water supply may appear endless,
there are compelling reasons to initiate comprehensive conservation
methods--these efforts are in line with a Supreme Court 1967 ruling
that limits Lake water diversion rates to 3,200 cubic feet per second,
regardless of the future development or population growth the area
has experienced. Policy documents of many major regional planning
agencies, such as the Chicago Metropolitan Agency for Planning
and the Alliance for the Great Lakes, emphasize potable water use
reduction to ensure the region’s ongoing water vitality.
Water levels in Lake Michigan have been falling, with only one
percent of the water in the Lake renewed each year. Ground water
levels have declined between 300 and 800 feet in the region, further
lowering Lake water levels. At the same time, demand for water
is expected to increase over the next 20 years, with a projected
population increase of 20% in the Chicago-Milwaukee region. With
both increasing demand and decreasing supply, it is critical for the
Chicago area to take prudent and sustainable measures to safeguard
against a dwindling fresh water supply.
At the same time, the Chicagoland area is experiencing increased
incidences of local flooding each year due to severe storms; flooding
within the City alone is largely a result of the City’s high water table
and combined sewer system (a sewer system in which wastewater
and stormwater are combined and treated in the same way). The
combined sewer system occasionally overflows (called a combined
sewer overflow or CSO) during major storm events, causing sewer
contents to discharge into a waterbody, such as Lake Michigan or the
Chicago River. Prevention of such flooding is important to minimize
the cost of damages as well as to protect water quality. These issues
can be at least partially ameliorated by reusing water and reducing
the load on the municipal sewer infrastructure.
Carter H. Harrison water intake crib 2 miles from the
Lake Michigan shore (1910)
http://en.wikipedia.org/wiki/File:HARRISON-
CRIB-1910.jpg
August 2011