The
Thames
Tideway Strategic Study - a study held
over the last five years and financed, largely
by Thames Water, unsurpringly, comes to the
conclusion that a large capital project is
required
and should be paid for outside the revenue from
water rates paid to Thames Water.
The Proposed
scheme
-
a 35km long storage tunnel will intercept
overflow sewage from just over half the CSOs
and transport it downstream to Crossness and
Beckton sewage works.
I have compiled a short list
of pros and cons here:
PROS
-
Least disruption
to the Capital
-
Provides much
needed extra storage for sewage system
-
System can
be expanded if necessary
-
Exciting engineering
project
-
Possible to
use for minor flood alleviation
CONS
-
'Solution' addresses the effects,
not the causes
-
The scheme would
be costly: est £1.7bn
-
The tunnel would take 15 years to complete
-
The tunnel's
capacity is 1.5million tons - total discharge
of CSOs are over 60million tons/year. The
tunnel concept was designed using estimated
discharges from a single overflow event
-
The tunnel would not extend West of Chiswick
and would not connect to Mogden STW
-
Only 35 out of 57 CSOs would drain into
the tunnel
Rainwater drainage still mixed with sewage,
rather than captured separately, while the
Capital is running short of drinking water
- Thames Water also proposed to build a water
desalination plant at Beckton to supply drinking
water from the filthy river!
This list is not
exhaustive, but it does highlight that this solution
is no panacea and may make little or no difference
to the water quality in the Upper Tideway. It
is likely that the tunnel may be needed along
with a host of other measures (see
aims).