It is Government policy to
leave mud in place whenever possible.
However, it is unavoidable that some mud will be dredged for certain
works such as emergency dredging for safety reasons; maintenance/deepening of the
harbour fairways, berths, anchorages or navigation channels; construction or
maintenance of rivers, stream courses or drainage channels; and certain
infrastructure development. The
East of Sha Chau area has been the site for a series of purpose-dredged pits
and exhausted sand borrow pits to provide contained disposal capacity for
contaminated mud arising from the Hong Kong Special Administrative Region’s
dredging, marine works and infrastructure projects. The disposal capacities are allocated to projects by the
Marine Fill Committee, and the on-site management of the facility is controlled
by the Chief Geotechnical Engineer/Fill Management (CGE/FM) of the Civil
Engineering and Development Department (CEDD).
The disposal demand for
contaminated mud was reviewed by ERM under Agreement CE 105/98 entitled
“Strategic Assessment and Site Selection for Contaminated Mud Disposal”. A forecast of the total disposal demand
was made in May 2001 when it was confirmed that the contaminated mud from CT9
would be disposed of at East of Sha Chau instead of in Mainland Waters. However due to the recently introduced
new sediment classification framework (specified in Environment, Transport and
Works Bureau Technical Circular (ETWBTC) 34/2002) for the dredged mud, there is
at present insufficient data to estimate future contaminated mud arising.
ERM in 2001 subsequently
reviewed the situation. It was
estimated that, based on best available information, the capacity of the
existing contaminated mud disposal facility at East of Sha Chau, Contaminated
Mud Pit (CMP) IV, would be exhausted by late 2008. ERM then recommended an intermediate facility for disposal
of contaminated mud during the period from 2009 assuming that a long-term
disposal facility would be ready for operation by 2017. This will provide uninterrupted service
to works projects requiring disposal of contaminated mud.
The
findings and the recommendations of the consultancy study were summarised in
the ACE-EIA Paper 4/2001. The
paper recommended a contained aquatic disposal facility (seabed pit) at Airport
East and an initiation of the Environmental Impact Assessment (EIA) study in
accordance with EIA Ordinance. The
paper was presented to the EIA Sub-committee of the Advisory Council on the
Environment (ACE) on 9.7.2001 and was discussed at the full ACE on
23.7.2001. The Council had no
objection to CEDD proceeding with the EIA study for the proposed site and
option but recommended that CEDD should keep all sites and disposal options
open as far as possible. CEDD
agreed at the ACE meeting to extend the study area to include East of Sha Chau
and to come up with the most suitable location and option for the proposed
facility. The proposed facility
would provide disposal capacity for a minimum of 8 Mm3 of
contaminated mud. The proposed
Airport East site is within an area where the water depth is between 5m and
15m. It is located to the
south-east of the existing East of Sha Chau pits. The East of Sha Chau area covers the existing CMP IVa, IVb
and IVc and the west of Brothers.
Both the South Brothers and East of Sha Chau areas have a similar
setting, i.e. slow current and mostly shallow water.
CED
commissioned ERM to provide professional services in connection with the Detailed Site Selection Study for a Proposed
Contaminated Mud Disposal Facility within the Airport East/East Sha Chau Area
Agreement No CE 12/2002 (EP).
During the course of the
study, two sites had been selected for the disposal of contaminated mud, namely the South Brothers (SB 2) and East Sha Chau
1 (ESC 1).
An EIA is being undertaken on
the two selected areas, which will provide information on the nature, extent
and cost of mitigation of environmental impacts arising from the construction
and operation of the selected sites and disposal options.
As
part of the EIA, a Marine Archaeological
Investigation (MAI) is required to assess potential impact on marine
archaeological resources of the selected sites.
The
objectives of this MAI include the following:
·
to
undertake a desktop review of marine archaeological sites in the project areas;
·
to
review available geophysical reports and data, and evaluate if further
geophysical survey is required;
·
to
establish the archaeological potential of the two selected sites; and
·
to
assess the potential impact that may arise from the development and recommend
appropriate mitigation measures where necessary.
This
report presents the findings of the MAI of the two selected sites, the East Sha Chau 1 (ESC 1) areas and one
third of the South Brothers (Pit A only).
CEDD is presently applying funding to cover the whole Study Area
(including Pit B and Pit C to the southwest of Pit A) of the South Brothers site and the MAI will be
undertaken during the detailed design stage prior to construction separately
reported to AMO.
Following
this introductory section, the remainder of the report has been organised as
follows:
Section
2 provides the legislative
framework for the marine archaeological assessments in Hong Kong;
Section
3 provides the findings of the
baseline review of the Study Area;
Section
4 provides the assessment
results of the geophysical survey review;
Section
5 assesses the archaeological
potential of the Study Area;
Section
6 presents the impact
assessment;
Section
7 provides recommendations and
conclusions of the MAI; and
Section
8 details the references for the
literature reviewed.
The
following Appendixes are also included:
Appendix
A Guidelines for Marine Archaeological
Investigation
Appendix
B Vessel Track Plot
The following legislation is applicable to the assessment of
cultural heritage resources in Hong Kong:
·
Environmental
Impact Assessment Ordinance (Cap. 499) and the associated Technical Memorandum
on the EIA Process (EIAO-TM);
·
Antiquities
and Monuments Ordinance (Cap. 53);
·
Guidelines
for Marine Archaeological Investigation prepared by AMO; and
·
Hong
Kong Planning Standards and Guidelines (HKPSG).
The
EIAO-TM outlines the approaches required in investigating and assessing
the impacts on cultural heritage sites. The following Sections of the EIAO –
TM are applicable:
Annex
19: “There is no quantitative
standard in deciding the relative importance of these sites, but in general,
sites of unique archaeological, historical or architectural value will be
considered as highly significant.
A baseline study shall be conducted: (a) to compile a comprehensive
inventory of places, buildings, sites and structures of architectural,
archaeological and historical value within the proposed project area; and (b)
to identify possible threats of, and their physical extent, destruction in
whole or in part of sites of cultural heritage arising from the proposed
project.”
The
EIAO – TM also outlines the criteria for assessment of impact on sites of
cultural heritage as follows:
Annex
10: “The criteria for evaluating
impact on sites of cultural heritage includes: (a) The general presumption in favour of the protection and
conservation of all sites of cultural heritage because they provide an essential,
finite and irreplaceable link between the past and the future and are points of
reference and identity for culture and tradition; (b) Adverse impacts on sites
of cultural heritage shall be kept to the absolute minimum.”
The
EIAO – TM also outlines the approach in regard to the preservation in
totality, in part, and not at all cultural resources:
Annex 19: “Preservation in totality will be a
beneficial impact and will enhance the cultural and socio-economical
environment if suitable measures to integrate the sites of cultural heritage
into the proposed project are carried out. If, due to site
constraints and other factors, only preservation in part is possible, this must
be fully justified with alternative proposals or layout designs, which confirm
the impracticability of total preservation.”
“This Ordinance
provides for the preservation of objects of historical, archaeological and
palaeontological interest…”
The Ordinance defines an antiquity as a relic (a movable
object made before 1800) and a place, building, site or structure erected,
formed or built by human agency before the year 1800. The Ordinance also states, amongst other things, that the
discovery of an antiquity shall be reported to the Authority (Secretary for
Home Affairs); that ownership of all relics discovered after 1976 shall be
vested in the Government; that the Authority can declare a place, building,
site or structure to be a monument, historical building or archaeological or palaeontological
site or structure (and therefore introducing certain additional controls for
these sites); and that licences and permits can be granted for excavation and
for other work.
Chapter
10 of the HKPSG provides guidelines relating to the conservation of historic
buildings, archaeological sites and other antiquities. The guidelines detail the methods for
the conservation and preservation of protected monuments, the method of
identifying and recording antiquities, particularly buildings that should be
conserved and the recording and grading of such buildings and archaeological
sites. The process of monuments
and the development control through the planning process is also highlighted.
Guidelines for MAI which detail the standard practice,
procedures and methodology which must be undertaken in determining the marine
archaeological potential, presence of archaeological artefacts and defining
suitable mitigation measures can
be found in Appendix A. Baseline
review, geophysical survey and establishing archaeological potential are
considered the first stage of a MAI.
Subject to the results of the first stage MAI, further investigation may
or may not be required.
The project covers two areas (see Figure 3.1):
·
an
area of seabed known as East Sha Chau 1 (ESC 1)—to the north of Chek Lap Kok;
and
·
South
Brothers (SB 2) - an area of seabed to the east of Chek Lap Kok, north of
Lantau Island.
Generally, the submarine deposits
in the Hong Kong region are subdivided into three formations, Chek Lap Kok
Formations and the overlying Hang Hau Formations.
The Chek Lap Kok Formations, the lowest part of the
Quaternary succession are considered to be Middle to Late Pleistocene in age
and consists of colluvium, alluvium and lacustrine sediments Fyfe, et.al.,
(2000). The marine sediments on
top of this formation are sediments related to the Holocene period (from about
13,000 BP to the present day) and referred to as the Hang Hau Formations
consisting of clayey silt sediments and some sand (mud, sandy mud).
The Sham Wat Formation, found between Chek Lap Kok
Formations and Hang Hau Formations is considered to be the Eemian deposit with
uncertain age and consisting of soft to firm silty clays with yellowish
mottling. This formation is
presently not widespread but only in a subcrop beneath the Hang Hau Formation
(Fyfe, et.al. 2000).
More modern sediments are related to the discharge from the
Pearl River, (and which would have an effect on the project area, being located
down stream from the mouth of the Pearl River) having a seasonal discharge of
about 370,000 million cubic metres each year (ibid). They consist of sand, mud and some gravel.
Fyfe, et.al (2000) further explains the rate of
sedimentation:
“In general, present day
sedimentation rates in Hong Kong waters are low, though they were undoubtedly
greater earlier in the Holocene when sea level was rising rapidly. … Without
tidal flushing, the sediment entering Victoria Harbour from the Pearl River,
sewage solids and losses from dredging and reclamation might be expected to
raise the seabed level by 40mm per year. However, comparison of Hydrographic
charts of Victoria Harbour from 1903 to 1980 revealed no conclusive evidence of
net sedimentation, implying that the seabed is a state of dynamic equilibrium.
Assuming that sedimentation in Hong Kong waters began about 8 000 years ago,
deposition of the 10 to 20 m of marine mud must have occurred at an average
sedimentation rate of between 1.25 and 2.5 mm per year. Available evidence
indicates that the rate of Holocene sedimentation has not been steady.
Radiocarbon dating suggests that the majority of sedimentation has taken place
over the past 4 000 to 5 000 years.”
During the late Pleistocene period (18,000BP) sea levels
began to rise until about 6,000 years BP and which is about the level of
present day sea level. “The extent
of the rise could be as great as perhaps 140 metres in parts” (ibid: 40).
The sediments of the Late Holocene period, considered to be
relatively homogenous very soft to soft silty clay and with high moisture
content, offers the greatest potential (as compared to the surface of the
seabed which is often found to have been disturbed by fishing and other
shipping related activities) to include well preserved remains associated with
the occupation and use of the islands in Hong Kong waters. These remains could include shipwrecks.
The coverage of the Hang Hau
Formation in the
South Brothers area varies from 17m to 25 m below sea level (PD) and there is a
band of about 10 m of marine deposits.
The ESC 1 area under investigation in this study is adjacent to four
groups of pits that have been used for the storage of contaminated mud. These
pits use the following design features (ibid):
· The pit would be dredged
to the base of the soft geological deposits, ie the Hang Hau and Sham Wat
formations.
· The pit would be dredged
to a commonly adopted rule of thumb side slope of 1:3.
· Through hydrodynamic
assessments made of previous purpose dredged CADs the pits are assumed to be
backfilled with contaminated sediments to a level of 3 metres below the
surrounding seabed level.
· On completion of
backfilling, the contaminated sediments would be capped with 3 metres of
uncontaminated mud subject to change upon detailed assessment to be carried out
in a later stage
In the South Brothers project area the water depth varies
from 7m to 11m below sea level (PD), in the ESC 1 project area the depth varies
from approximately 5.5m to 7.5m below sea level (PD).
Archaeological evidence indicates that seafarers have
used the waters of Hong Kong for around 6,000 years (Bard, 1988). In Chau
(1993) it is reported that:
“In the past
decade, a great number of prehistoric sites have been discovered in the coastal
sandbars which represent the opening up of the coastal and offshore island
areas by the early settlers. Around six thousand years ago, the Neolithic folks
had already settled in the coastal area of South China.”
Coates (in Braga, 1957)
stated that “Definite archaeological traces of this prehistoric activity have
been found … on the beach at Shek Pik, on the south coast of Lantao [Lantau]
Island. From these finds it is clear that about three thousand years ago the
islands were used as a seasonal entrepôt for trade between the Yangtse mouth,
the tribal states of what is to-day Kwangtung Province, and Indonesia.” The
islands at the mouth of the Pearl River were seen as more suitable for trade
between the Cantonese merchants and those from other regions, and “Temporary
settlements were built near the beaches. Cooking utensils have been found from
this period on Lamma and Lantao, but no trace of buildings.”
Further information states
that:
“Local history,
still very far from being recorded fully, begins with the migration of Chinese
into the area during the Sung dynasty (960-1279). … Lantao Island is the next
of the group to appear in history. The last reigning Sung emporer, Ti-ping,
made Kowloon his rallying point in the long Chinese retreat before the Mongol
invasion. In 1279, not far from Tsuen Wan, his forces met the Mongols and were
finally defeated. After the battle large numbers of the Court and nobility
escaped across the comparatively narrow, sheltered stretch of water to Lantao.
… Of those who fled to Lantao, there were those who settled and possibly
intermarried with the inhabitants, traces of these cultured refugees are to be
found at Tai O. … The Mongols did not enjoy for long their conquest of South
China. The early part of the fourteenth century was a troubled time in the
South, and from the Kowloon peninsula a number of families moved to safety in
remoter spots. The families at present occupying villages in the Shek Pik area
of Lantao moved there during the period of Mongol rule (1279-1368).”(ibid).
Meacham (1994) noted that “The
history of Chek Lap Kok [to the south of ESC 1 and west of the South Brothers]
spans the entire period of human occupation in the Hong Kong area, from the
earliest inhabitants of the painted pottery period around 4000 BC to the recent
period.” As part of the rescue archaeological project carried out on Chek Lap
Kok before the construction of the international airport, archaeological work
was carried out on several sites on Chek Lap Kok, including a 8th-10th
century site encompassing kilns and coins; burial sites of the Northern Sung
period; a site containing pottery from the Middle and Late Neolithic period
(4000-1500 BC); burial/ritual sites dated 3700-3400 BC; a number of Tang lime
kilns (dated 750 and 1200 AD); and a site containing hard and soft geometric
pattern pottery, axe moulds and cloth from the Bronze age. In 1993, part of a cannon was discovered
during dredging of the seabed between Chek Lap Kok and Tung Chung (Meacham,
1994). The discovery was then
reported to the Provisional Airport Authority. Inscriptions found on the cannon revealed that it was
manufacturing in 1808. This
cannon is likely related to the fort at Tung Chung, reflecting the Chinese
military presence in the area in the past.
Lantau Island, just to the south of the Study Areas, is the
largest and most western of the islands in the Hong Kong group of islands and
therefore provides shelter for the waters between it and Hong Kong Island.
Being located at the outlet of the Pearl River “…rightly called the artery of
Southern China” (Lo, 1963) the area had “…established contacts with the outer
world by the Chin Dynasty (ibid: 2). An early maritime industry was the pearl
fishing industry and “…governmental control of this activity only began in the
time of the Five Dynasties…” (Lo, 1963). Lantau Island also became a prolific
incense-producing district, although “…nothing remains of it to recall the
origin of the name Hong Kong (i.e. Fragrant Port)” (ibid). The bay inside of
Lantau Island attracted “…trading vessels from Arabia, Persia, India,
IndoChina, and the East Indies…” (ibid), and local vessels involved in the
fishing and salt making industries. Pirates were prolific in the area, as well
as settling on Lantau Island, and forts and batteries were also built on the
island to assist the Imperial Navy in controlling pirates.
It is only a few miles north of the project area, ie. Lin
Tin (Neilingding) and Tuen Mun, that the Portuguese (the first European
arrivals) established a presence there in 1513 (see Figure 3.2). The Portuguese explorer, Jorge Alvares was permitted
to land on Lin Tin and for “…about ten months he spent in the Canton River, at
the anchorage of T’un Men…” as this was “…where all the foreign trade in south
China was conducted (Braga, 1965). “ Landward and closer to him, across the
stretch of waters to the east, he could see towering Ching Shan (now known as
‘Castle Peak’) standing guard over the anchorage of T’un Men. A little to the
north, the headland of Nan Shan [on Figure 3.2] reared its form
protecting the naval station of Nan Tou [on Figure 3.2], with the
Imperial junks lying at anchor, under the guns of the fort on little Ta Shan
Island [on Figure 3.2]; and a considerable movement of ships at the port
of Nan Tou showed that it was an important town.” (ibid).
Further on this discovery of China by Europeans and
containing an account of the significance of this area for trade in general can
be found in a report by Tomé Pires (Cortesão, 1944) a Portuguese living in
Malacca and which is “…based possibly to some extent on information gathered by
Jorge Alvares in China.” (ibid). “…Pires has a lot to say about the ports and
the peoples who traded in China. He mentions that junks from Malacca anchor “in
the port of Tumon.” Those from Siam anchor, he states “in the port of Hucham.”
Our port of Tumon is three leagues nearer to China than the Siamese one.” If
our theory is correct that the island of Tumon is none other than Lin Tin
Island, then it is likely that Hucham would be the port of Lantao Island.”
(ibid). Cortesão in Braga (1965) states “The city of Canton (Quamton) is where
the whole kingdom of China unloads all its merchandise…” and “Salt is a great
merchandise among the Chinese. It is distributed from China to these regions;
and it is dealt with by fifteen hundred junks which come to buy it, and it is
loaded in China to go to other places.” (ibid).
Lo (1963) further illustrates the importance of the area
surrounding the Study Area:
Though the trading contacts of
T’un-mên with overseas countries can be traced back to quite ancient
times—probably beginning in the Liu Sung period—it was during the T’ang Dynasty
that trade greatly extended. … As traffic increased and more travellers passed
through T’un-mên literary men began to learn of this place and its trading
activities.
The sovereign of Nan Han who
seized power during the disintergration of the T’ang and established himself in
southern China made it his policy to secure the support of outlaws, to extend
his sway to the non-Chinese peoples, the Mans and the Tans (people who live on
boats) and to derive the maximum profit from with foreign countries.
Consequently special attention was paid to T’un-mên. When the Five Dynasties came to an end and the Sung emporers
ascended the throne, governmental machinery in the T’un-mên area was
elaborated. In addition to the royal garrison, an officer whose duty was to
pursue and arrest bandits was installed. A system of administration for the
land-locked waters and more remote seas was put into force at T’un-mên and two
other posts (one at P’i-p’a Chou at the northern tip of Lantau Island, and one
at Tan-kan Chou of Ju-chou). …during the Sung only three places on the coast
round the outlet for Canton, namely T’un-mên, Kuan-fu Ch’ang and Ta-Yu Shan
(Lantau) were guarded by imperial troops.
It is evident that the region between Lantau and Lintin and T’un-mên—the region that takes in the
Study Area for the mud disposal was populated, and active in the movement of
people and materials between various parts of China, and several other nations,
over a period of at least 4000 years.
A brief contemporary description of the area around Chek Lap
Kok can be found in Hownam-Meek (1978):
“ To the N of Lantao lie the
Brothers, the Western of which has an abandoned graphite mine on its W side.
... The whole area to the North of Lantao is now occupied by shipping laid up
as a result of the recession. … A mile S x E of Tung Ku lies the attractive Sha Chau, a series of rocky cones standing on
the sandpits. There is a tiny Joss House on one islet and a good anchorage
under the lee in 1.5 to 2 fathoms mud. The beaches are completely deserted.”
A review of a number of charts was carried out to ascertain
if there were any other written records of shipwrecks in the ESC 1 and South
Brothers area.
Shipwrecks are predominantly the primary archaeological site
located underwater (Muckelroy, 1978).
Since they are random and haphazard events it is difficult to predict
their exact location as little written references survive or were ever made.
British Admiralty Charts 342 (published 1962), 341 and 1919
(published 1989), and 1503 (published 2002) highlight one wreck in the ESC 1
area, but only on BA 342 (see Figure 3.3). The wreck did not
appear on the later charts.
Contact was made with the Hong Kong Hydrographic Office and
upon checking their records, they found two “suspected wreckages”, the closest
to the Project Areas being about one nautical mile to the west of East Sha
Chau.
Contact was made with the United Kingdom Hydrographic Office
and they provided information about two ‘live’ shipwrecks within two nautical
miles of the two Project Areas. The closest shipwreck is about one nautical
mile from the western edge of East Sha Chau, being the same shipwreck as that
reported from the Hong Kong Hydrographic Office.
Although the baseline review of the literature found the two
Project Areas have potential for underwater cultural heritage sites, no sites
of historical or archaeological significance were identified from the
literature, or the charts.
As part of an MAI, the objective of the review of the
geophysical survey is to define the areas of greatest archaeological potential,
assess the depth and nature of the marine sediments to define which areas
consist of suitable material to bury and preserve archaeological material, and
to map anomalies on the seabed and below, which may be archaeological
material.
A review of the geophysical report and data was carried out.
Under the routine monitoring programme of the East Sha Chau
disposal facility, the Hong Kong Office of the Institute of Geophysical and
Geochemical Exploration (IGGE) undertook a geophysical survey in May/June 2003,
of the East Sha Chau Survey Area([1])
encompassing the existing pits and surrounding area, including the selected
area ESC 1 (see Figure 4.1).
The objectives of the survey were
to map out all seabed features and textures in the survey area (IGGE,
2003). The survey included a
marine multi-beam echo sounding and side scan sonar survey using 15m, 30m (for
echo sounder) and 80m (for side scan sonar) line spacing. The survey did not include a
seismic investigation, or any vibrocores.
A geophysical survey of the South
Brothers Site ([2])
(see Figure 4.2) was implemented by EGS (Asia) Ltd., on the 29th
July and 30th July 2004.
This survey comprised a multi-beam echo sounder using 20m survey lines,
a marine seismic reflection survey and a side scan sonar survey, both using 40m
survey lines (EGS, 2004). The
above survey only covers one third of the South Brothers Site (Pit A).
The following equipment was used during the geophysical
survey of ESC 1:
· ELAC
SEA BEAM 1185 & Transmit/Receive Unit SEE 30 Multi-beam Sonar system;
· Edgetech
560A Side Sac Sonar;
· Trimble
NT-300D DGPS differential signal receiver;
· Season
TRACKER Navigation System;
· Valeport
VLR740 Automatic Tide Logger.
The calibration, accuracy, processing systems used, and
outcomes are described in IGGE (2003).
The following equipment was used during the geophysical
survey of South Brothers:
· Desco
25 single frequency echo sounder;
· The
Allied Signal ‘Bottom Chart’ multibeam system;
· Klein
System 3000 side scan sonar with digital tow fish;
· C-Boom
Low Voltage Boomer and hydrophone;
· C-View
data acquisition and processing package v 1.35
· C-Nav
Gc GPS Globally corrected system calibrated at Tuen Mun Typhoon Shelter
· The
EGS computerised navigation package v1.06 and PC;
· Seba
Recording Tide Gauge (CLP Power Station).
The
quality assurance used during the survey of South Brothers ensured a position
accuracy of +/- 0.3m (EGS, 2004).
The geophysical survey data
obtained by IGGE was processed by in-house geophysicists and a total of 17 maps
and 19 figures were produced which provided a very accurate 3 dimensional
representation of the seabed of ESC 1 (at 10 cm depth intervals and 15-30m
horizontally). A number of seabed
features (anchor marks and dumped material) were annotated on the original records
and noted on the appropriate maps.
These data were reviewed by a qualified marine archaeologist to verify
the sonar anomalies/seabed features.
The depth of water varied between 3.5m (top of disposal
pits) and 27.6 m (at base of pits) throughout the whole survey area. In the ESC 1 Survey Area, where there
has been no dredging, the depth varies from approximately 5.5m to 7.5m.
The geophysical survey data obtained by EGS of the South
Brothers Project Area was processed by in-house geophysicists using their C-Nav
interpretation and processing software and interpretation of the seismic data
from the records which were then digitized and used for plotting and
contouring. A comprehensive report
on the methods, interpretations and results, together with 9 figures were
produced (EGS, 2004).
In the South Brothers Project Area , the depth of the water
varied from 7m to -11m below sea level (PD). Side scan sonar data revealed a highly disturbed seabed
attributing to anchoring, dredging and trawling. A number of sonar contacts were identified. Sub bottom profiling accurately mapped
the base of marine deposits, the base of the alluvial sediments and the top of
Grade III rock. (EGS,
2004:2). Three sub bottom
anomalies (obstructions) were encountered of an unknown nature. According to EGS’s Geophysicists, these
features are normally
associated with sub surface utilities such as water pipe, sub-sea cable, and
boulder in the sediments. However,
as the possibility of these features with archaeological interest could not be
ruled out, further investigation is considered necessary. The above
review covers one third of the South Brothers Site (Pit A). Sonar
Anomalies/Seabed features
ESC 1 Survey Area contained
only scattered materials, most likely natural, dumped materials, and some
anchor marks. “No anomalous objects with obvious height on the seafloor were
found. Some small and scattered high-reflection lumps have been found on the
seabed….” (IGGE, 2003).
In the South Brothers Survey
Area the side scan sonar survey revealed more than 26 seabed features, all
interpreted by the EGS geophysicist to be small amounts of debris and dumped
materials (see Figure 4.3).
Other seabed features included shell gravel (high reflective sonar
patches) finer sediments (low reflective sonar patches) and numerous scars from
anchoring, dredging and trawling.
The three sub bottom ‘obstructions’ located in the Project Area are of
an unknown nature. The above review covers one third of the
South Brothers Site (Pit A).
A review of the data, maps and figures for ESC 1 and South
Brothers Project Areas by a marine archaeologist, Mr William Frederick Jeffery,
verified the conclusions of the geophysicists that the seabed contained only
natural or dumped materials. The
two Project Areas had been greatly impacted by anchoring, trawling and dredging
and the likelihood of it containing any well-preserved remains is very minimal. The potential for well-preserved
remains greatly increases below the seabed, and while there is no concrete
evidence that the sub bottom anomalies/obstructions encountered in the South
Brothers area are of a marine archaeological nature, it is a possibility and
they needs to be verified (Figures 4.4 and 4.5). The
Geophysical Survey for the South Brothers area covers one third of the South
Brothers Site (Pit A).
The review of the historical documents and literature
indicated that the region in the vicinity of ESC 1 and South Brothers was
occupied and used by Chinese, then many other foreign traders for many
years. The islands of the region
contain archaeological evidence of occupation from about 4,000 years ago,
including evidence of the use of the sea, and material from the seabed, during
that time. The islands of this region became important trading centres for
trading vessels from Arabia, Persia, India, IndoChina, the East Indies, and the
Portuguese. They also became bases for the many Pirates, given the region’s
many maritime activities and therefore potential for plunder.
The literature review indicates that of the two Project
Areas, South Brothers would offer the greatest potential from an historical
viewpoint for containing archaeological material, given its sheltered location
and proximity to Lantau Island and Chek Lap Kok. The seabed in the region encompassing ESC 1 and South
Brothers has potentially been affected by the deposition of sediments flowing
down the Pearl River. Both Project
Areas have been greatly impacted by anchoring, trawling and dredging and the
likelihood of the areas containing any well-preserved remains minimal.
Below the seabed and the Pearl River sediments, it is
considered that the sediments of the Late Holocene period, the Hang Hau
Formation, offers the greatest potential to include well preserved remains
associated with the occupation and use of the islands. The South Brothers area contains a layer
of this formation of generally more than 10m in thickness. Fyfe, et.al states
(2000): “… that the seabed is in a state
of dynamic equilibrium. Available evidence indicates that the rate of Holocene
sedimentation has not been steady. Radiocarbon dating suggests that the
majority of sedimentation has taken place over the past 4 000 to 5 000 years.”
The findings from the review of the charts and the
literature for the two Survey Areas, ESC 1 and South Brothers, failed to locate
any evidence of archaeological or historical significant material. The seabed investigations of the two
Project Areas also failed to locate any cultural material. It is a possibility that the
encountered three sub bottom obstructions found in the South Brothers Project
Area are cultural heritage material of archaeological/historical significance
or recently dumped material of no archaeological/historical significance.
Based on the review of charts and literatures of the Project
Area and supplemented by review of Geophysical Survey data at ESC 1 Survey
Area, evidence of marine archaeological interest is not identified. Therefore, no impact on any marine
archaeological deposit arising from the construction of the Mud Disposal Facility
is expected.
The review of the charts and literature of this Project Area
failed to pin-point marine archaeological deposit in the area. The Geophysical Survey data is
inconclusive whether marine archaeological material is located within the area
as the identification of three sub bottom obstructions encountered during the
survey was not implemented. The Geophysical Survey covers one third of the
South Brothers Site (Pit A), further assessment will be undertaken in the
detailed design stage, prior to construction and reported to AMO
separately.
The review of literature indicated that the region adjacent
to ESC 1 and South Brothers had been occupied for over 4,000 years and had been
a focal point for Chinese and international maritime trade. It, therefore, offers the potential to
include sites and objects of archaeological and historical significance. However, a review of charts identified
no shipwreck record within either survey area.
Geophysical Survey findings indicated that both of the
Survey Area had been heavily disturbed by anchoring, trawling and
dredging. The likelihood of either
area containing any well-preserved remains is considered minimal.
Although no concrete evidence was found by the Geophysical
Survey that the South Brothers area contained no cultural material, three
obstructions were found below the sea bed that could prove to be such material. It could also prove to be recently
dumped material.
It is concluded that no marine archaeological resources are
identified in the ESC 1, but there is a possibility that this material could be
located in the South Brothers Project Area, from identification of the three
sub bottom obstructions encountered.
In order to determine the archaeological potential of these obstructions
and ensure that, if they are in fact of archaeological importance no impacts
occur, it is proposed that a qualified archaeologist conduct a Watching Brief
during dredging works. Such a
brief is only considered necessary in the area where the obstructions are
located. Full details on the
Watching Brief, as well as the proposed archaeologist, should be submitted to
and approved by AMO prior to the commencement of works.
The Geophysical
Survey covers one third of the South Brothers Site (Pit A), further assessment
will be undertaken in the detailed design stage, prior to construction and
reported to AMO separately.
Bard, 1988, In Search of the past: A guide to Antiquities of
Hong Kong
Braga, J. M.,
1965, China Landfall 1513. Jorge
Alvares Voyage to China.
A complilation of some relevant material. Macao. Imprensa Nacional.
Cortesão, A., 1994, The Suma Oriental of Tomé Pires and The Book of Francisco Rodrigues. London.
Hakluyt Society.
Chau, Hing-wah, (ed) 1993, Collected essays on the culture of the
Ancient Yue People in South China. Hong Kong Museum of History. Hong Kong.
Coates, A., 1957, The Islands.
In Braga, J.M. (Compiler), 1957, Hong Kong Business Symposium. South China
Morning Post. Hong Kong.
EGS, 2004, Contract Number
GE/2003/18, Works Order Number GE/2003/18.35, Geophysical surveys at Pit A near
South Brothers. Preliminary Report, Job Number HK 188904.
ERM, 2002, Detailed Site Selection Study for a
Proposed Contaminated Mud Facility within the Airport East/East Sha Chau Area
Agreement No. CE 12/2002 (EP). Civil Engineering Department.
Fyfe, J.A., Shaw, R., Campbell, S.D.G., Lai, K.W. and Kirk,
L.A., 2000, The Quaternary Geology of Hong Kong. Hong Kong Geological
Survey, Geotechnical Engineering Office, Civil Engineering Department, The
Government of Hong Kong, SAR.
Hownam-Meek,
R.S.S., (Ed.) 1978, Afloat in Hong Kong.
T. Thomas Ltd. Hong Kong.
Institute of Geophysical and Geochemical Exploration
(IGGE), 2003, East Sha Chau Contaminated Mud Disposal Area: Geophysical
Survey. Preliminary Report for
Geotechnical Engineering Office, Civil Engineering Department. (Unpublished)
Hong Kong.
Lo, Hsiang-Lin, 1963, Hong Kong and its External Territories
before 1842. Institute of
Chinese Culture. Hong Kong.
Meacham, William, 1994, Archaeological Investigation on Chek Lap Kok. The Hong Kong Archaeological Society.
Hong Hong.
Muckelroy, K., 1978, Maritime Archaeology. Cambridge University Press.
Annex G – Appendix A Guidelines
for Marine Archaeological Investigation
Annex G – Appendix B Vessel
Track Record
