Environmental Impact [E(TA)31]Assessment Ordinance
(Cap. 499)
Section 5(7)
Environmental Impact Assessment
Study Brief No. ESB-101/2002
Name of Applicant:
Drainage Services Department
(hereinafter known as
the ˇ§Applicantˇ¨)
1. BACKGROUND
1.1
An application (No. ESB-101/2002) for an
Environmental Impact Assessment (EIA) study brief under section 5(1) of the
Environmental Impact Assessment Ordinance (EIAO) was submitted by the Applicant
on 22 March 2002 with a Project Profile (No. PP-165/2002) for the captioned
proposed project.
1.2 The
proposed project includes the following major items of works:
(i)
Pak Ngan Heung River with location shown
in Figure 1:
(a)
construction of approximately 140 m
four-cell culvert flood bypass under the emergency vehicle access (EVA) for the
hairpin meander leading downstream of the access bridge;
(b)
construction of approximately 130m of
channel by using grasscrete and masonry lined banks with natural bed both at
the upstream and downstream of the flood bypass culvert and reprovision of the EVA and the 3.5 m wide access road; and
(c)
extension and enlarging of existing
U-channel of approximately 120 m to reroute the runoff from Butterfly Hill
around the low lying area of Ling Tsui Tau Tsuen into the Pak Ngan Heung River.
(ii)
Tai Tei Tong River with location shown in
Figure 2: construction of 350 m of channel using grasscrete and masonry lined
banks with natural bed from Mui Wo primary School to the rivers confluence.
(iii) Luk
Tei Tong 2 River with location shown in Figure 3: construction of 400m of
channel using grasscrete and masonry lined banks with natural bed.
(iv) Luk
Tei Tong River with location shown in Figure 3 : Extension of existing gabion
channelisation downstream to River Silver confluence using a grasscrete and
masonry lined channel with natural bed.
1.3 The
proposed project is a Designated Project under Schedule 2 Part I of the EIAO
and requires an environmental permit under the EIAO for its construction and
operation.
1.4 Pursuant to
section 5(7)(a) of the EIAO, the Director of Environmental Protection (the
Director) issues this EIA study brief to the Applicant to carry out an EIA
study.
1.5
The purpose
of this EIA study is to provide information on the nature and extent of
environmental impacts arising from the construction and operation of the
proposed project and related activities taking place concurrently. This information will contribute to
decisions by the Director on:
(i) the overall
acceptability of any adverse environmental consequences that are likely to
arise as a result of the proposed project;
(ii)
the conditions and requirements for the
detailed design, construction and operation of the proposed project to mitigate
against adverse environmental consequences wherever practicable; and
(iii) the
acceptability of residual impacts after the proposed mitigation measures are
implemented.
2. OBJECTIVES
OF THE EIA STUDY
2.1
The objectives of the EIA study are as
follows:
(i)
to describe the proposed project and associated
works together with the requirements for carrying out the proposed project;
(ii) to identify and
describe the elements of the community and environment likely to be affected by
the proposed project and/or likely to cause adverse impacts to the proposed
project, including both the natural and man-made environment and the associated
environmental constraints;
(iii) to identify and
quantify emission sources and determine the significance of impacts on
sensitive receivers and potential affected uses;
(iv) to identify any
potential impacts from point and non-point pollution sources on the identified
water systems and sensitive receivers during the construction and operation
stages;
(v)
to identify and quantify any potential
losses and damage to flora, fauna and wildlife habitats;
(vi)
to identify any potential impacts to the
historical, archaeological and cultural resources and propose measures to
mitigate these impacts;
(viii) to propose the provision of
infrastructure or mitigation measures so as to minimize pollution,
environmental disturbance and nuisance during construction and operation of the
proposed project;
(ix) to identify, predict
and evaluate the residual (i.e. after practicable mitigation) environmental
impacts and the cumulative effects expected to arise during the construction
and operation phases of the proposed project in relation to the sensitive
receivers and potential affected uses;
(x) to identify,
assess and specify methods, measures and standards, to be included in the
detailed design, construction and operation of the proposed project, which are
necessary to mitigate these environmental impacts and reducing them to
acceptable levels;
(xi) to investigate the extent
of secondary environmental impacts that may arise from the proposed mitigation
measures and to identify constraints associated with the mitigation measures
recommended in the EIA study, as well as the provision of any necessary
modification;
(xii)
to design and specify the environmental
monitoring and audit requirements, if required, to ensure the implementation
and the effectiveness of the environmental protection and pollution control
measures adopted; and
(xiii) to consider alternatives with
a view to avoiding or minimizing the potential environmental impacts to the
sensitive uses, and to compare the environmental benefits and dis-benefits of
each of the different drainage channel design and to provide reasons for
selecting the preferred design(s) and to describe the part environmental
factors played in the selection.
3. DETAILED
REQUIREMENTS OF THE EIA STUDY
3.1 The
Purpose
The
purpose of this study brief is to scope the key issues of the EIA study. The Applicant has to demonstrate in the
EIA report that the criteria in the relevant sections of the Technical
Memorandum on the EIA Process of the EIAO (hereinafter referred to as the TM)
are fully complied with.
3.2 The
Scope
The
scope of this EIA study covers the proposed project mentioned in section 1.2
above. The EIA study shall address
the likely key issues described below; together with any key issues identified
during the course of the EIA study.
(i)
the potential impacts on the drainage
system, hydrology, ground water, and water quality on the Luk Tei Tong
freshwater marsh during construction and operation phases of the proposed
project,
(ii)
the potential aquatic and terrestrial
ecological impacts on the Luk Tei Tong freshwater marsh and Butterfly Hill
Conservation Area arising from the construction works, including loss of
habitats, removal of vegetation and disturbance to animals of the proposed
project;
(iii)
the potential noise and dust impacts to
sensitive receivers during the construction phases, in particular at areas near
the school(s), village houses and other residential dwellings of the proposed
project; and
(iv)
the potential impacts on the cultural
heritage sites, in particular Chung Hau Archaeological Site, and the two historical
watch towers at Luk Tei Tong and Chung Hau, if they are affected by the
construction works of the proposed project.
3.3
Consideration
of the Alternative Drainage Channel Designs and Construction Methods
3.3.1 The
Alternative Drainage Channel Designs
The
project has potential to cause loss of habitat at the Luk Tei Tong freshwater
marsh and the associated riparian habitat and the Butterfly Hill. The Applicant should justify in the EIA
report why the drainage channel design stated in the project Profile has been
selected among other possible alternatives, including environmental and other
considerations. A comparison of the environmental benefits and dis-benefits of
the possible drainage channel designs shall be made.
3.3.2
Consideration
of Alternative Construction Methods and Sequences of Works
Having
regard to the cumulative effects of the construction period and the possible
adverse construction impacts to the affected sensitive receivers along the
rivers, the EIA study shall also explore alternative construction methods and
sequences of works for the proposed project with a view to avoiding and
minimising adverse environmental impacts to the maximum practicable
extent. A comparison of the
environmental benefits and dis-benefits of applying different construction
methods shall be made. The
Applicant shall take into account the environmental implications of potential
flooding at downstream areas in wet seasons during construction phases in the
comparison.
3.3.3
Taking into the comparisons in sections
3.3.1 and 3.3.2 above, the Applicant shall recommend/justify the adoption of
the drainage channel design that will avoid or minimize adverse environmental
impacts.
3.4 Technical
Requirements
The
Applicant shall conduct the EIA study to address all environmental aspects of
the activities as described in the scope as set out above and subject to the
findings under section 3.3. The
EIA study shall include the following technical requirements on specific
impacts:-
3.4.1 Ecological Impact (Both Terrestrial and Aquatic)
3.4.1.1 The
Applicant shall follow the criteria and guidelines for evaluating and assessing
ecological impact as stated in Annexes 8 and 16 of the TM respectively. The assessment area for the purpose of
terrestrial ecological assessment shall include all areas within 500 m distance
from the site boundary of the works areas, or the area likely to be impacted by
the proposed project. For aquatic
ecology, the assessment area shall be the same as for the water quality
assessment described in section 3.4.2.2.
3.4.1.2 (i) The
project involves channelization of natural rivers, which will disturb the
bottom sediments, alter water movement of the four rivers (Pak Ngan Heung
River, Tai Tei Tong River, Luk Tei Tong River, and Luk Tei Tong 2 River) and
affect the riparian habitats.
Therefore important habitats including the Luk Tei Tong freshwater
marsh, which has a direct ecological linkage with the Luk Tei Tong river
system, and Butterfly Hill and the flora and fauna living in or associated with
the rivers may be affected by the project. As such, the ecological baseline of the four
rivers and the affected areas should be properly established, the environmental
impact from the project thoroughly assessed and effective mitigation measures
suggested in the EIA report;
(ii) In
the ecological impact assessment, the Applicant shall examine the flora, fauna
and other components of the ecological habitats within the assessment
area. The aim shall be to protect,
maintain or rehabilitate the natural environment. The assessment shall identify and quantify as far as
possible the potential ecological impacts on the areas such as natural river,
riparian, wetland and woodland habitats and the associated wildlife arising
from the proposed project, including the impacts of any haul roads, temporary
work sites and access.
3.4.1.3 The
assessment shall include the following:
(i) A
review of the findings of relevant studies and collating all the available
information regarding the ecological characters of the assessment area;
(ii) Evaluation
of the information collected and identification of any information gap relating
to the assessment of potential ecological impacts to the terrestrial and
aquatic environment;
(iii) Carrying
out the necessary ecological field surveys (the duration of which shall be at
least 9 months and shall cover both the wet and dry seasons) and investigations
to verify the information collected, fill the information gaps identified and
fulfil the objectives of the EIA study;
(iv) Establishing
the general ecological profile and describing the characteristics of each
habitat found; major information to be provided shall include:
(a)
description
of the physical environment;
(b)
habitat
maps of suitable scale (1:1000 to 1:5000) showing the types and locations of
habitats in the assessment area;
(c)
description
of the ecological characteristics of each habitat type including size,
vegetation type, species present, dominant species found, species diversity and
abundance, community structure, seasonality and inter-dependence of the
habitats and species, and presence of any features of ecological importance;
(d)
representative
colour photos of each habitat type and of any important ecological features
identified;
(e)
species
found that are rare, endangered and/or listed under local legislation,
international conventions for conservation of wildlife/habitats or red data
books;
(v)
Investigation
and description of the existing wildlife uses of relevant habitats with special
attention to those wildlife groups and habitats of conservation interests;
including:
(a)
woodlands;
(b)
natural
stream courses and associated stream fauna;
(c)
wetlands;
(d)
vertebrates
(e.g. avifauna, mammals, fish, herpetofauna);
(e)
macro-invertebrates
(e.g. dragonflies, butterflies);
(f)
and any
other habitats and wildlife groups identified as having special conservation
interests such as Romerˇ¦s Free Frog by this EIA study;
(vi)
Description
of all recognized sites of conservation importance in the proposed project site
and its vicinity and assessment of whether these sites will be affected by the
proposed project or not;
(vii)
Using suitable methodology,
identification and quantification as far as possible of any direct, indirect,
on-site, off-site, primary, secondary and cumulative ecological impacts such as
destruction of habitats, reduction of species abundance/diversity, loss of
feeding grounds, reduction of ecological carrying capacity, habitat
fragmentation; and in particular habitat loss and disturbance to stream and
wetland-dependent wildlife groups during the construction stage;
(viii)
Evaluation
of the significance and acceptability of the ecological impacts identified
using well-defined criteria;
(ix)
Recommendations
for all possible alternatives, such as modifications of layout and design and
practicable mitigation measures to avoid, minimize and/or compensate for the
adverse ecological impacts identified, such as reinstatement of habitats
temporarily affected by the proposed project to its original state and if
possible with some enhancement features;
(x)
Evaluation
of the feasibility and effectiveness of the recommended mitigation measures and
definition of the scope, type, location, implementation arrangement, resources
requirement, subsequent management and maintenance of such measures;
(xi)
The EIA
study shall aim at maintaining the natural streams in the study area if the
ecological field survey as described in (iii) above suggested that they are
ecologically important streams.;
(xii)
The EIA
study shall address the impact on aquatic wildlife in streams due to this
project. The study period should include June/July as high summer and wet
season, October as passage migration period, and January to April as dry season
and spring migration period.
The habitants of the streams / rivers, i.e. aquatic wildlife, will be
firstly affected by the project;
(xiii)
The EIA
study shall address the habitat loss, in particular at freshwater marsh at Luk
Tei Tong, and the hydrology due to the captioned project
(xiv)
Determination
and quantification as far as possible of the residual ecological impacts after
implementation of the proposed mitigation measures;
(xv)
Evaluation
of the severity and acceptability of the residual ecological impacts using
well-defined criteria;
(xvi)
A review
of the need for and recommendation for any ecological monitoring programme is
required; and
(xvii)
Planning on
the ecological monitoring after channelization of the three rivers should be
included in the future EIA to assess the successfulness of recolonization of
flora and fauna in the disturbed rivers and riparian habitats. Contingency habitat rehabilitation plan
should also be considered in the EIA, in case wildlife recolonization is shown
to be unsuccessful.
3.4.2 Water
Quality Impact
3.4.2.1 The
Applicant shall follow the criteria and guidelines for evaluating and assessing
water pollution as stated in Annexes 6 and 14 of the TM respectively.
3.4.2.2 The assessment area for
the water quality impact assessment shall include all areas within 500 m from
the project boundary, the area shall include but not limited to the Luk Tei
Tong freshwater marsh. This assessment
area could be extended to include other areas such as stream courses and the
associated water system in the vicinity being impacted during the course of the
EIA study if found justifiable.
3.4.2.3 The Applicant shall identify and analyse all physical, chemical and biological disruptions of fre