Environmental Engineering Reference
In-Depth Information
water quality conditions at the time, this was certainly untrue for the Tame
and the onset of the Second World War in 1939 exacerbated the already
polluted state. Little effect of any pollution control was observed until legisla-
tion in the 1960s began to place quality and quantity controls on all domestic
and industrial point discharges (Lester
1975
). Further initiatives included treat-
ment lakes in the lower river and rerouting of major sewers which took
effluents from the upper reaches to treatment works downstream. This devel-
opment also allowed the closure of many ineffective smaller treatment works.
Also in the 1960s, gas production from coal was replaced by natural gas and the
grossly polluting gas-works effluents ceased. These plus economic decline in
the region led, as we will see, to a considerable reduction of the pollution load
in the river.
Sites and methodology
Three sites on the main River Tame were selected for this initial study, one on
the lower reaches, one in the middle reaches and one in the upper reaches
within the Black Country region.
Site 1. Chetwynd Bridge (OS Ref. SK 187138) is located 1.6 km upstream of
the confluence with the River Trent. The mean flow of the river is about
2000 million litres per day. The nearest tributary upstream is the River Anker
which is mostly of medium to good quality. This site integrates practically the
whole of activities that affect water quality in the Tame basin.
Site 2. Lea Marston (OS Ref 206934) is located 32 km upstream of the conflu-
ence with the Trent. The main tributaries upstream are the Blythe, the Cole and
the Rea. The Blythe is a clean river and the others, once polluted, have now
cleaned to a great extent.
Site 3. Eagle Lane, Tipton (OS Ref. SO 979931) is located some 65.5 km
upstream of the confluence with the Trent and about 5 km downstream of
the Oldbury source. The feeders are all the once grossly polluted streams
of the Black Country and the coal measures, and there is no known 'natural'
or unpolluted reach upstream of this site.
The main datasets originate from biological and chemical surveys begun in
the 1950s (Woodiwiss
1964
) and continuing to the present day (Environment
Agency Registers BIOSYS and WIMS). Raw chemical data from surveys before
1980 were not available; therefore, summarised data were extracted from
various annual and special reports dating back to the 1930s. There have been
changes to chemical or biological techniques over the years, but the data
treatments and methods of representation have been standardised here as
much as possible for comparability.
For this initial study, we have carried out a univariate analysis using ammo-
nia concentrations (mg L
1
as N) as the primary chemical indicator of pollution
as it can reflect both industrial and non-industrial categories (Klein
1962
).
There are also data on the toxicity of ammonia to many aquatic organisms
