3 - International Joint Commission

2.4 ST. CLAIR RIVER/LAKE ST. CLAlR/DETROIT RIVER
The St. Clair River drains Lake Huron and flows south into Lake St.
Clair. It is 64 kilometres long. The river is an important international
shipping channel and is used for commercial, industrial, and domestic
purposes. Several refineries and petrochemical plants discharge to the St.
Clair River and the volume of these discharges is about 0.5% of the total river
flow (DOE and MOE, 1985). The industrial inputs of contaminants are much
greater than the municipal ones (Marsalek, 1986). There are 32 permitted
discharges to the river in the U.S., including 6 municipal sewage treatment
plants (IJC, 1987a). There are 12 industrial and 6 municipal dischargers on
the Canadian side of the river. These point sources and non-point sources,
including contaminated sediments, have led to the degradation of river water
and sediments. Many toxic chemicals have been identified in a 100 metre
wide area along the Ontario shore near Sarnia’s chemical industrial area.
High levels of chlorinated organics such as PCBs, and volatile hydrocarbons,
and heavy metals such as mercury and lead have been found in sediments.
Spills are a significant problem in this area. Between 1972 and 1984, 175
spills were recorded, of which 161 discharged directly into the river or a
tributary (IJC, 198713). In 1986, there were 48 spills, 10 of which were on the
U.S. side of the river (UGLCCS, 1989).
The St. Clair River flows into Lake St. Clair. The average depth of Lake
St. Clair is about 3.4 metres. Mean inflow from the St. Clair River accounts
for 98% of the oufflow to the Detroit River. The theoretical flushing time of
the lake is 7.3 days. The lake supports the spawning grounds for over 30
species of fish and is one of the most heavily used sport fishing and
recreation areas of the Great lakes. Until recently, the lake also supported
a commercial fishery.
The Detroit River is 51 kilometres long and connects Lake St. Clair and
Lake Erie. It is used extensively for shipping, recreation and public and
industrial water supplies. Contamination of the water and sediments by
metals and a variety of organic chemicals from municipal, agriculture and
industrial waste has led to significant degradation. The majority of the
sources, particularly of PCBs, are located along the U.S. shore (UGLCCS,
1989). The Rouge River is a major source of contaminants to the Detroit