NEWS FROM EUROPE AND AROUND THE
Updated on 25th June 2001:
Ramspol Project, Netherlands
Installation of the world's largest inflatable
rubber dams has finally commenced at a site near the city of
Kampen in the Netherlands. The first of three 8.0m high x 60.0m
long dams was lifted on to the concrete foundation on 31st May.
This dam has now been installed and tested. The second dam is
also complete. This will be tested on 29th June.
The dams are to be used as storm surge barriers
to close off the Ketelmeer as part of a scheme, under the Delta
Plan, to protect the western part of the Province of Overijssel.
The dams are inflated using a combination of air and water.
When in normal use, they will remain deflated and will lie hidden
below the normal water level. The project should have been completed
in July 2000, however, the work was suspended almost as soon
as the contract was awarded in 1998 pending a design review
by the Civil Engineering Division of Rijkswaterstaat. Differences
in design philosophy between Rijkswaterstaat and the rubber
dam manufacturer were subsequently resolved but only after Rijkswaterstaat
had carried out a detailed analysis of stress concentrations
in the dam rubber bodies. The latest delays are understood to
have involved design problems with the bearings on the rollers
that support the rubber body when deflated. The project will
probably not be completed until Autumn 2002, a delay of more
than two years on the original completion date.
River Guadiana, Spain
Two 3.0m high x 40.0m long rubber dams installed
on the Guadiana River in Merida, Spain will have to be replaced
only six months after being installed. The dams suffered severe
abrasion damage while lying deflated on the concrete foundation.
The dams had not been operated since being installed in September
2000. It is understood that the design of the concrete foundation
produced an irregular flow pattern over the deflated dams which,
combined with a high downstream water level, resulted in the
rubber bodies repeatedly rubbing against the concrete surface.
The civil contractor, Dragados - Altech JV, will conduct model
tests in July to determine the exact cause of the failure and
also to assess whether to install a replacement rubber dam or
to look for an alternative solution.
Theun-Hinboun Power Project, Lao PDR
The Canadian consultant, Acres International,
has been appointed by Theun-Hinboun Power Company (THPC) to
advise on the repair or replacement of five 3.0m high x 32.0m
long rubber dams installed at the Theun-Hinboun power plant
in Lao PDR. The dams were installed at the site in 1997 to raise
the available head at the power plant in periods of low flow.
One of the five dams failed in May 1998 barely six months after
being brought into operation. This was replaced in December
1998. A second dam failed last year and other dams have suffered
abrasion damage. It is understood that the consultant will advise
THPC on whether to remove all the dams and to use an alternative
solution or to accept a proposal from the dam manufacturer to
replace the damaged dam and to repair the other dams.
River Besos, Barcelona, Spain
A further seven 1.0m high rubber dams will
be installed on the River Besos which flows into the Mediterranean
north of Barcelona, Spain. This follows installation of five
1.2m high x 42.5m long dams in the section of river that passes
through Santa Coloma de Gramanet in April 1999. Tenders were
submitted to the client, Infraestructuras 2004, in May and an
announcement on the chosen contractor/supplier is awaited. The
project involves re-development of a 7km section of the river
to provide an aquatic park, cycle track and other leisure facilities.
River Wertach, Germany
Tenders have been submitted for supply of
two 2.24m high x 20.0m long rubber dams on the River Wertach
in Ausgburg, Germany. The dams are to be used as intake gates
at a small hydropower plant. A 3.7m high x 32.0m long rubber
dam, which is currently the highest air-inflated rubber dam
in Europe, was installed on the same river at Turkheim (about
30km upstream from Augsburg) in 1998.
River Gunz, Germany
A 2.2m high x 22.0m long spillway gate was
installed this month at a small hydropower plant on the River
Gunz in Gunzburg, Germany. This is the first spillway gate to
be installed in Germany and the first in the European Union.
Currently, there are two spillway gates in operation in Europe,
one in Hungary and the other in Iceland.
Lake Osten, Sweden
VBB Viak AB of Stockholm, Sweden has issued
a tender for construction of regulating weir which includes
supply of two, 1.85m high spillway gates. The gates which are
20.0m and 16.0m long are to be used to control flow in the River
Tid about 200m to 300m from the Lake Osten outlet. The tender
closing date is 29th June 2001 and the gates are due to be installed
River Mapocho, Chile
The project developer, Bancard S.A., has
submitted a proposal to the Ministry of Public Works to re-develop
six sections of the River Mapocho in Santiago, Chile. The project,
which will be privately financed, involves installation of nineteen
1.0m to 4.8m high rubber dams with lengths in the range 30.0m
to 80.0m. The value of the rubber dam supply is estimated to
be about US$11.5 million. The project, if approved by the Ministry
of Public Works, is scheduled to commence construction in 2003.