of the Lower River Tame
School of Civil Engineering, University of Birmingham
rivers throughout the world have undergone degradation due to
pollution and flood defence works. It is now recognized that this
is unacceptable and rehabilitation is necessary. The West Midlands
River Tame is an excellent study site having heavily impacted
reaches and some restored reaches. The University of Birmingham is
undertaking a major Natural Environment Research Council (NERC)
study of the river as a contribution to the Urban ReGeneration of
the ENvironmenT (URGENT) thematic research program. The study of
the management of the Lower River Tame is, among one of the many
contribution towards this program.
To identify the
sources and sinks of pollution at the Lower Tame.
To investigate how
the river response to forcing functions such as pollution load
inputs and flow.
To understand the
kinetics of the Lower River Tame.
To predict changes
of water quality in the river for various rehabilitation
The Lower Tame
stretches from Water Orton till confluence with River Trent. It is
situated in the West Midlands conurbation and combined with the
Upper Tame, has the biggest urban catchment area in the whole UK.
Inputs from three major sewage treatment works flows into the
Lower Tame; Minworth (Activated Sludge Plant & Humus Tank),
Coleshill and Tamworth, see Fig.1.
research project involves analyzing existing water quality and
flow data obtained from monitoring stations along the Lower Tame.
In addition, the utilization of a stochastic computer modelling
that calculates the river water quality throughout a catchment
called SIMCAT is involved. Sampling and other fieldwork is
undertaken in order to facilitate the validation of these
Environment Agency has strategic chemical water quality targets
for all rivers. River Tame mostly fails due to high ammonia and
BOD (Biological Oxygen Demand) level and ammonia is thus,
discussed in greater depth and detail.
& Sinks of Pollution Load
Fig.2, the main ammonia load input into Lower Tame is accounted to
Minworth HT due to poor performance of Minworth STW during
1993-96. It has since been improved and hence, causing significant
improvement in water quality (see Fig.4). Although Lea Marston
purification Lakes is efficient in removing BOD loads, diffusion
of ammonia from the bed causes a significant ammonia increase in
the Lower Tame.
Response to Pollution Load
3, in the first 10km downstream from Water Orton, the discharge of
treated effluent from STW causes an increase in ammonia level.
Approaching the lakes, further increase of ammonia is observed due
to ammonia diffusion from its bed. Since tributaries such as River
Cole also contribute ammonia loads into the river and flow is
small, no significant dilution or self-purification of the river
Beyond the lakes, there is a massive recovery of ammonia, reducing
the ammonia level from 2.5 to 0.8 mg/l. This optimistic response
is slightly puzzling because to produce such a massive recovery,
the decay rate of ammonia would be unrealistically high (roughly
about 10 times the average value).
in Ammonia Uptake
preliminary hypothesis to explain the massive ammonia recovery
observed beyond the lakes is that algae are taking up the ammonia.
Algae are photoautotrophic organism commonly found in rivers,
either living at the riverbed as benthic algae or suspended in the
water column. It needs nutrients such as ammonia and phosphorus
for growth and reproduction. Assuming that the hypothesis is true,
estimation of alga concentration is needed to determine if the
amount is reasonable. To find out the concentration of algae in
the Lower Tame through fieldwork sampling and laboratory test
would be time consuming. A preliminary estimation of alga
concentration is thus calculated based on the U.S Environment
Protection Agency guide. From this, alga concentration of roughly
about 300 mg/l is obtained, which is the value one would expect
from an urban river. However, more research needs to be done for
Changes of Water Quality
1998-1999, major work has been undertaken to improve the
performance of STW, especially at Minworth HT under the water
industry’s agreed capital investment programme (AMP 2). The
effects of this in terms of water quality improvements are
predicted. From Fig.4, with reduced impact from the STWs, the
ammonia level along Lower Tame is reduced, particularly at river
stretches before approaching the lakes. The response of Lower Tame
remained the same, with the lakes still generating ammonia.
& Future Work
understanding of the kinetics and sources/sinks of pollution
at Lower Tame.
water quality due to future improvements are strongly
dependent on Water Orton.
results of the role of algae in ammonia uptake at Lower Tame
need to be found.
need to be extended to the Upper Tame, together with obtaining
a better understanding of its kinetics.
GIS will be used to
incorporate existing knowledge and the model results, and will
provide an input to the Decision Support System, which will
aid the evaluation of rehabilitation strategies.