Water Quality Management - River Dynamics and Integrated River Management - page 549

began to gain major attention in urban areas in the 19 th Century. As a result of building sewers (initially
combined stormwater and sanitary flow systems and later separate sanitary and stormwater systems)
without treatment, many urban rivers became heavily overloaded and gave off an obnoxious stench, which
was caused by anoxic decomposition of sewage and garbage in streamwater and muds. For example,
Novotny (2003, p. 6) reported that every summer from the 19 th Century to the middle of the 20 th Century,
the stench from the Thames River in London became so unbearable that the British Parliament recessed
during the affected periods. Industrial pollution also placed a heavy load on urban rivers. In the 1950s,
flammable waste discharges from the greater Cleveland-Akron industrial area caused the Cayahoga River
in Ohio, U.S. to catch on fire. Whereas the burning Cayahoga River gained national and international
fame similar fires were frequent in other U.S. rivers in the 1950s and 1960s such as the Chicago Waterway
System and the Rouge River near Detroit. Finally, the untreated wastewater led to substantial public health
problems in many cities because of pathogens. For example, lack of sanitation contributed to more than
1800 deaths due to typhoid in Chicago in 1892 (Engineering Board of Review, 1925) and over 3,000
deaths due to cholera in Brussels in 1866 (Archives D'Architecture Moderne, 1997).
As shown in the previous examples between the mid-19 th and mid-20 th Centuries, water quality in major
urban rivers throughout the world had deteriorated to such an extent that the public and governments in
many areas had to take strong steps. For example, the stench of the Milwaukee River in Milwaukee, U.S.
was so bad that in 1880 the city government authorized the building of two flushing tunnels by which
clean Lake Michigan water was delivered to two discharge points on the river and its tributary upstream
from the city. These flushing tunnels are still in use during periods when low dissolved oxygen is detected
in the river. Novotny (2003, p. 11) reported that the City of London applied a comprehensive wastewater
treatment program, and by 1970, the Thames River in London was alive again, and fish have been caught
there since. Chicago reversed the direction of flow of the Chicago River away from Lake Michigan (its
water supply source) and toward the Des Plaines River in the Mississippi River basin, which together with
the Pasteurization of milk lead to the virtual elimination of deaths due to typhoid in Chicago. Brussels
covered over the Zenne River to relieve its public health problems and provide space for new modern
squares and boulevards in the center of the city (Archives D'Architecture Moderne, 1997).
In the latter part of the 20th Century problems resulting from non-point source pollution from agricultural
areas also became more pervasive and apparent. Novotny (2003, p. 21) reported that the Black Sea, Adriatic
Sea, Chesapeake Bay, and Gulf of Mexico are examples of large bodies affected by transboundary and/or
global inputs of non-point source pollution. These bodies suffer from one common symptom—excessive
inputs of nutrients from farming operations and cities located thousands of kilometers upstream and brought
in by large tributary rivers. The result of the high nutrient loads has been excessive algal development in
the upper zone of the water body and anoxic (lack of oxygen) conditions in the deeper zone. Novotny
(2003, p. 21) reported that 53% of U.S. estuaries experience hypoxia (reduced oxygen levels) or anoxia
for at least part of the year. The most famous example of hypoxia in the U.S. is the hypoxic zone in the
Gulf of Mexico that can reach an area as large as 19,000 km 2 . In China, the overabundance of nutrients
has resulted in a rapid increase in the size and frequency of toxic red tides from less than 10 in the 1960s
(see Fig. 1.36) to 453 from 2001 to 2005. The China Daily (February 13, 2006) reported that among the
453 red tides between 2001 and 2005, 132 covered more than 100 km 2 each and 33 covered more than
1000 km 2 each. Most of these red tides occurred in areas adjacent to the Yangtze River estuary and the
marine area south of Zhejiang Province.
Whereas the individual solutions in London, Milwaukee, Chicago, Brussels, and other locations
resulted in improved local water quality, by the late 20 th Century it was clear water quality problems
needed to be solved in a comprehensive manner. The water pollution problems discussed in the foregoing
paragraphs and many others led national and international bodies to develop laws and regulations for