Environmental Engineering Reference
In-Depth Information
CHAPTER THIRTEEN
Ecological recovery in a river polluted
to its sources: the River Tame
in the English Midlands
TERRY E. L. LANGFORD, PETER. J. SHAW, SHELLEY R.
HOWARD,ALASTAIRJ.D.FERGUSON,DAVID
OTTEWELL AND ROWLAND ELEY
Introduction
In many industrialised regions particularly in Britain, rivers have been
impounded for use by mills, polluted by multiple point sources and channe-
lised to the very source over many centuries (e.g., Bracegirdle
1973
; Lester
1975
;
Harkness
1982
; Holland & Harding
1984
; Haslam
1991
). Since the 1960s, the
ecological recovery of such historically polluted and disturbed rivers in Britain
has been remarkable. Long reaches of once black, foetid, fishless watercourses,
some almost completely devoid of macroscopic biota, have been transformed
into clear streams and rivers with diverse floras and faunas and prolific fish
populations. This transformation is perceived to have been the result of a
number of factors, including law, public pressure, new technologies, new
infrastructure and changes in the economy and industry. Even so, ecological
recovery is still poorly advanced in some rivers and the reasons for this have
not been explained in any detail. This short chapter uses sets of long-term
chemical and biological data from three sites on a Midland river in a prelimi-
nary analysis of the possible reasons for the variable rates of ecological recovery
and the relationship between the long-term chemical and biological changes in
the river. It is part of a series of longer term studies of the problems associated
with ecological recovery of polluted rivers (e.g., Langford et al.
2009
).
Ecological recovery of any ecosystem from a disturbance has been defined as
'the return to an ecosystem which closely resembles unstressed surrounding
areas' (Gore
1985
). Gore and Milner (
1990
) state that 'as normally used,. . .
recovery. . . implies that the system is moving toward a condition that existed
before it was disturbed'. In a river recovering from pollution, the ultimate
