Docstoc

THE DUMPING OF CHINA CLAY WASTE IN THE RIVERS AND SEAS OF ST

Document Sample
THE DUMPING OF CHINA CLAY WASTE IN THE RIVERS AND SEAS OF ST Powered By Docstoc
					An appraisal of proposed sea defences, February 2005
by John Henry Woods

Qualifications & Work Experience

Chartered Engineer,
      Member of the Institution of Civil Engineers
      Member of the Chartered Institution of Water Environmental Management.

       1956 -1962     Trainee Engineer with Essex River Board
       1962 -1966     Engineer with Cornwall River Authority
       1966 -1967     Site Engineer, Stithians Joint Water Committee
       1967 -1969     Senior Site Engineer- Gleeson Civil Engineering ontractors
                      Construction of Siblyback Dam
       1969 -1970     Senior Site Engineer- Gleeson Civil Engineering River
                     Parrett Flood Relief Scheme, Somerset
       1970 -1974     Senior Engineer Cornwall River Authority
       1974 -1989     Operations Engineer, South West Water,
                     Responsible for day-to-day running of Flood defence
                     in Cornwall
       1989 -1993     Operations Engineer, National Rivers Authority,
                     responsible for day-to-day running of flood defence
                     in Cornwall

       October 1993 Retired - still living in Cornwall.

INTRODUCTION :
In the summer of 2003 I was concerned to see in the Newspapers an illustration
of a proposed large residential development on the beach at Carlyon Bay. My
concern was for the safety of several hundred people living on the beach at the
foot of cliffs in exposed conditions.


I inspected the site in August 2003 and read the publicity brochure. I visited the
site again in January 2005 and have studied the current submission. My fears
                                             1
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
have not been allayed. I consider the site to be inherently unsafe and that it is
not possible to protect it from the sea.


FLOOD RISK ASSESSMENT :


The applicant‟s flood risk assessment confirms that the site is indeed liable to
flooding and storm damage. The point at issue is whether it can be protected.
(A point of equal importance is whether it should be protected). There are no
long-term records of sea levels and wave heights for this beach.


All the calculations in the report are modifications of data from elsewhere and
generalised computer programmes. There are so many caveats, reservations
and alternative possibilities as to render the accuracy of the estimates of the
heights and return periods questionable.


A more reliable assessment of what is likely to happen can be gained by
reference to the written and photographic evidence of storms around the South
Coast of Cornwall and Devon.


In appendix 1, I have compiled a collection of such reports and photographs
comprising only of references from my own bookshelf and some recent press
cuttings. More detailed research would produce many more examples.
One thing that is immediately obvious is the capacity of waves when striking a
solid wall, to throw huge quantities of water, sand, rocks and other debris high in


                                             2
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
the air. To deliberately place houses and apartments directly in the path of such
elemental forces is, I suggest sheer folly.


FLUVIAL FLOODING :


I would not wish to contest the design calculations for fluvial flows but have some
reservations about the methods of dealing with surface water run-off and the
control of the Sandy River outfall. These are dealt with later.


THE DESIGN OF THE SEA DEFENCES :


1. The basic concept.


Although the proposed defences are substantial their effectiveness and integrity
depend upon the constant maintenance of sand levels on the seaward face of
the wall. For reasons set out below I consider this to be impossible and this
invalidates the whole scheme.


2. Maintenance of sand levels.


The logistical problems of bringing huge quantities of sand to site are dealt with
elsewhere. The difficulties of placing them exactly when and where required
cannot be overcome. With an empty site, that is before construction of buildings,
it may be possible to tip sand at a particular place along the wall but once all the


                                             3
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
houses and apartments are built this will not be possible as the site road is at the
rear of the buildings.


Having tipped the sand, where possible, the problem of moving and placing it
along the beach is insurmountable during periods of high tide when the beach is
covered particularly in a storm situation. This is when the sand is likely to be
most needed as any damage can be caused in the course of a few hours.


Another problem is that a high proportion of spring tides occur in the hours of
darkness when the days are short. Even in daylight with the tide out the
movement of machinery on a steeply sloping soft beach would be difficult. From
my own experience it would seem likely that tracked, as opposed to wheeled,
machinery would be required.


The long-term maintenance of the beach in the years after the developers
have left the site needs to be evaluated in terms of cost and responsibility.


3. The profile of the sand.


It is proposed that the profile of the beach will be the same as the existing beach,
which although variable, is steep but at a higher level. The beach at Carlyon Bay,
like most beaches around the Cornish coast, is subject to considerable
fluctuations and can change overnight.




                                             4
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
The proposition that the recharged beach will remain constant in height
and profile reflects a great act of faith by the designers.


Under the heading “Description of Modelling Methods” the report states that the
sediment size on Carlyon beach is greater than most sand beaches and smaller
than shingle beaches and I quote:- “as far as it is known, there are no models
that have been designed or shown to predict changes in profile of a beach having
the grain size, permeability and gradient of those found in Carlyon Bay”.
Therefore two computational models have been used, one relevant to sand and
one relevant to shingle.


The normal limitations of modelling as a means of forecasting are therefore
considerably increased.


4. The Profile of the Concrete Wall


The curved profile of the concrete wall is designed to throw back the sea, this it
will do but not without huge amounts of spray going over the wall. In the normal
undeveloped state of the beach any large waves dissipate their energy as they
move across the beach to the foot of the cliffs. With the proposed design there
will be huge impact energy as waves hit the wall much further down the beach.
This energy will be dissipated in the form of spray and the creation of undertow
as the water rushes back, scouring away the sand as it goes.


5. The Stability of the Sea Defence Structure

                                             5
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
The long-term and even the short-term stability of the structure must be suspect
as it is, in effect, “floating” in the sand. In other words it is not keyed into the rock
below, therefore the possibility, or one might say probability, of lateral and
vertical movement (settlement) cannot be ruled out.


6. The possibility of Scour


The possibility of a dramatic lowering of the beach with resultant scouring of the
toe of the structure is recognised in the report under para.5.3.3. To counteract
this I quote:- “In order to prevent undermining of the sea wall rock armour,
protection must extend to below the minimum-expected beach levels during the
structure lifetime”. The possibility of “unexpected” beach levels is a cause for
concern.


7. The Effect of the Beach Outfall of Sandy River


Massive works are proposed to ensure that the outfall of Sandy River is taken to
a point beyond which it can interfere with beach levels.


In the normal course of events, the river meanders along the front of the beach
creating huge gullies in the sand. As with all other aspects of the design, it is
hoped that the forces of nature will comply with the design proposals.




                                              6
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
Based on many years‟ experience of the White River outfall at Pentewan Beach,
I predict that from time to time a change in wind direction will cause the outfall to
be blocked with the result that the channel will fill with sand and the river will spill
over the side of the open channel, meander across the beach and disturb the
sand levels as it always has.


8. Drainage of surface water from the Site.


It is recognised that the sheet piling of the wall will interfere with the natural
drainage of the site. Under para.7.2 it states:- “The sea wall will incorporate a
sheet piled foundation that will interrupt the flow path to the sea. It is proposed
that a large diameter perforated pipe situated between the sea wall and sea front
buildings, will drain the sub-soil as well as the promenade and roofs of the
buildings fronting the sea. The pipe, which will also act as attenuation storage,
will discharge to the Sandy River at its outfall through the promenade.


There must be doubts about the effectiveness of such a method, particularly
in the long term. How often will the pipe become blocked and require cleaning
out? Will the Sandy River channel become blocked with sand to the extent that
the pipe outfall will not function?


9. Dealing with spray overtopping the Sea Defence


In my opinion this is a major problem in the development of this site. Experience
indicates that in extreme conditions vast amounts of water could cascade over

                                              7
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
the site (See Appendix 1) The proposed method of dealing with this is described
in the Wardell Armstrong document page 13.


“The primary sea wall will have gaps at the stairways to allow free drainage of
overtopping waters. A secondary wall will comprise the promenade, which will
have a parapet wall 1.2m high. This will have gaps at walkways to allow drainage
of
overtopping water. The third line of defence, for much of its length, is the front
wall of the buildings with gates in the gaps between the buildings”.


The problem is that water that goes through any gates which are left unclosed, or
over them or even spray which goes over the buildings, plus the run-off from
heavy rain, will flow down into the underground car parks and flood the road.


Water could be „ponded‟ behind the promenade with the only means of discharge
being via the Sandy River outfall which could itself be blocked or subject to wave
action. The response to this is to hope that it never happens.


10. The possibility of structural damage from overtopping spray containing
     sand, rocks and other debris.


Apart from the risk of flooding, overtopping spray can contain solids, presenting
risk to life and limb and structural damage to buildings. Anyone living in Cornwall
or Devon who reads the Western Morning News or watches local television will
know that pictures frequently appear showing waves crashing over promenades

                                              8
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
     c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                           email press@carlyonbaywatch.co.uk
                               www.carlyonbaywatch.co.uk
and sea walls with children and even adults dodging them. After-the-storm
pictures frequently show roads and promenades littered with debris.


A recent report from Southampton University states that between 1999 and 2002
there were 12 recorded deaths caused by people being swept from coastal
paths, breakwaters and sea walls in Britain. A lesser concern but nevertheless
relevant, is who will be responsible for clearing up after storms at this private
development?


11 Proposed Flood Warning System


The very need for a flood warning system confirms that these proposed
properties will be in a flood risk area.




CONCLUSIONS


      There is no dispute that this site will be subject to storms. Past history
       suggests that storms which will cause damage to this site will occur much
       more frequently that once in 200 years.




                                             9
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
      The proposed sea defences depend for their effectiveness and integrity on
       the continued maintenance of beach levels. This I submit is not practical
       or possible.


      Even if the wall remained effective, the apartments would, in a storm,
       receive a battering from spray and flying debris.


      The method of dealing with large amounts of spray and run-off from heavy
       rain by means of a perforated pipe would be hopelessly inadequate. This
       would lead to flooding of the low area behind the apartments, including the
       road and underground car parks.


      Because the only escape route for residents is via the road at the foot of
       the cliffs, and with the possible flooding of the road and underground car
       parks, the evacuation of hundreds of people in a serious incident would be
       impossible, particularly in the dark.


      It would therefore, in my view, be totally irresponsible to allow residential
       development to proceed.


My conclusions and observations are based entirely on the current
position and take no account of predicted rises in sea levels due to global
warming.




                                               10
                                   CarlyonBayWatch
                      Representing Residents of Carlyon Bay and Charlestown
   c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                         email press@carlyonbaywatch.co.uk
                             www.carlyonbaywatch.co.uk
APPENDIX 1


Storms and Wave Damage on the South Cornwall and South Devon Coast


MOUSEHOLE - History of Storm Damage. Dec 1989 and most recently Oct.
2004
NEWLYN - History of Storm Damage. Dec 1989 and most recently Oct. 2004
PENZANCE - History of overtopping by spray over promenade leaving debris on
coast road.
MARAZION Storm damage in recent years
PORTH LEVEN, LOE BAR, MULLION- all affected by serious storm damage but
as this is Atlantic coast it is not directly comparable with Carlyon Bay.
FAMOUTH & PENRYN - History of tidal flooding.
FLUSHING - Frequent tidal flooding,
ST. AUSTELL BAY - before the advent of motorised lifeboats, there were two
lifeboats stationed in St. Austell Bay to assist ships in storms, one at Mevagissey
and one at Polkerris.
GORRAN HAVEN History of storm damage. Several times the quay was
destroyed and rebuilt.
PORT MELLON Road frequently overtopped. Suffered damage in Oct. 2004
MEVAGISSEY - Despite huge protective walls has still sustained damage.
CHARLESTOWN Report that in Oct. 2004 houses high above the harbour walls
were affected by spray.

                                             11
                                 CarlyonBayWatch
                    Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
PENTEWAN - Long history of changing beach levels and blockage of White
River outfall. The old breakwater has been progressively damaged by the sea. In
October 2004 there was flooding from the sea.
SPIT TUNNEL - Prone to blockage with sand and rocks.
PAR HARBOUR - Joseph Austin built the harbour. In his own words:- “From the
exposed situation of the Bay, before I could mature any works connected with
the intended Wharves, I found it necessary to defend them from the violence of
the sea…” From a letter to the authorities dated March 1848.
POLKERRIS - History of Storm damage.
FOWEY - History of tidal flooding
POLPERRO - History of storm damage.
LOOE - Periodic tidal flooding Promenade to beach overtopped in Oct. 2004
flooding lifeboat station.
SEATON -(Cornwall)- Periodic flooding of coast road with large deposits of sand.
KINGSAND - History of storm damage. Sustained damage in Oct. 2004.
PLYMOUTH - Geographically this is comparable with Carlyon Bay but with the
additional protection of Plymouth Breakwater. History of tidal flooding. Suffered
storm damage in Dec. 1989 when the Waterfront Restaurant suffered serious
damage.
HALLSANDS - Complete village of 36 houses was washed away in one night in
1917 due to loss of sand from the beach.
TORCROSS - History of storm damage. Severe damage in 1970‟s.
SLAPTON SANDS - Frequent damage to coast road. Washed away in 2003.
PAIGNTON & TORQUAY - Frequent overtopping of promenade leading to
closure of coast road.

                                              12
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
    c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                          email press@carlyonbaywatch.co.uk
                              www.carlyonbaywatch.co.uk
TEIGNMOUTH & DAWLISH - Railway line and sea wall frequently damaged with
suspension of rail services.
EXMOUTH - Sea defences damaged Oct. 2004
SIDMOUTH - History of storm damage.
SEATON - History of tidal flooding.


Cuttings to accompany Appendix 1


1.    Cutting 6/5/2004, entitled “Beach is Flood Risk”. “A report by the
Government’s chief scientist, Sir David King. Sir David’s report makes clear
that the likelihood of flooding and coastal erosion in Cornwall and other
parts of the UK caused by global warming, such as Carlyon Bay, are in the
danger zone.”
2 Picture of damage at Newlyn - from “Storm Force “ Page 7
3     Picture of Cadgwith- from “Storm Force” page 15.
4 Cutting-Hundred years ago re Falmouth.
5 Cutting from Cornish Guardian with picture of Carlyon Bay and report dated
     30.12.04
6 Picture of tidal flooding at Looe. Page 40 in “Storm Force”
7 Picture of sand on road- Seaton. Cornwall page 45 “Storm Force”.
8 Plymouth- pictures showing storm damage and flooding- “Storm Force” pages
     6,7, 15.
9 Cutting Western Morning News 3.4.04. about Hallsands
10 Cutting showing storm at Torcross in the 1970‟s


                                              13
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
     c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                           email press@carlyonbaywatch.co.uk
                               www.carlyonbaywatch.co.uk
11 Cutting Western Morning News 11.11.03 concerning destruction of coast road
     at Slapton Sands.
12 Picture of wave- Western Morning News 6.12.03 Hope Cove
13 Cutting Western Morning News- 13.1.04 Waves at Dawlish.
14 Cutting Western Morning News Waves at Dawlish. 9/7/2004
Extracts from a publication named “Storm Force”, published by Western
Morning News :
15 Page 18 Inundation by sand at Teignmouth
16 Page 62 Waves at Sidmouth.
17 Page 61 Storm damage at Sidmouth.
18 Page 19 also at Sidmouth.
19 Page 10 Huge amounts of water overtopping promenade- Seaton Devon.
20    Floods of expectation - from Water and Environment manager- Oct 2003.




                                              14
                                  CarlyonBayWatch
                     Representing Residents of Carlyon Bay and Charlestown
     c/o 1, Wheal Northey, St.Austell, PL25 3EF. Tel : 01726 810918 Fax : 01726 67480
                           email press@carlyonbaywatch.co.uk
                               www.carlyonbaywatch.co.uk

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:17
posted:5/28/2010
language:English
pages:14