CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8 ECOLOGICAL IMPACT

Introduction

8.1 This chapter assesses the impacts of the Project upon terrestrial ecology, intertidal ecology and subtidal ecology.

8.2 The Outlying Islands Sewage Scheme Stage 1 Phase II Package J consists of the provision of a sewer system for the Sok Kwu Wan area of Lamma Island as well as sewage treatment and disposal facilities. The sewer system includes pumping stations and gravity sewers/rising mains to collect and transfer the sewage and wastewater arising from the Sok Kwu Wan catchment area to the proposed sewage treatment and disposal facilities. The proposed sewage treatment and disposal facilities include a rising main from the proposed sewage treatment works to a submarine effluent outfall offshore.

8.3 Ecological baseline surveys including a dive survey were conducted from autumn 1998 to summer 1999. A verification survey was conducted in April 2002 to update and verify the ecological data collected. A coral mapping survey was also performed in May 2002. A detailed assessment of ecological impacts of the Project was made based on the baseline conditions. Efforts were made in the planning of the Project to avoid ecological impacts as much as possible. Mitigation measures were developed as necessary to minimize or reduce negative impacts to acceptable levels.

Environmental Legislation, Policies, Plans, Standards and Criteria

8.4 The following Hong Kong SAR Government legislation and guidelines are relevant to the assessment of impacts to ecology:

· Forests and Countryside Ordinance (Cap. 96); · Forestry Regulations (Cap. 96, subsidiary legislation); · Country Parks Ordinance (Cap. 208) and associated subsidiary legislation; · Marine Parks Ordinance (Cap. 476) and associated subsidiary legislation; · Town Planning Ordinance (Cap. 131); · Wild Animals Protection Ordinance (Cap. 170); · Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187); · Environmental Impact Assessment Ordinance (Cap. 499) and associated Technical Memorandum on Environmental Impact Assessment Process (the "TM"); and · "Guidelines for Implementing the Policy on Off-site Ecological Mitigation Measures" (PELB Technical Circular 1/97, Works Branch Technical Circular 4/97, dated 17 February 1997) (the "TC").

8.5 This study also takes note of the following relevant international agreements:

· Convention on Wetlands of International Importance Especially as Waterfowl Habitat ("Ramsar Convention"); · Convention on the Conservation of Migratory Species of Wild Animals ("Bonn Convention");

MAUNSELL Page 8/1 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

· Convention on International Trade in Endangered Species of Wild Fauna and Flora ("CITES"); and · Convention on Biological Diversity.

Description of the Environment

Recognised Sites of Conservation Importance

8.6 The following recognised sites of conservation importance are located at or near the study area and are shown in Figure 8.1:

Ÿ Potential Country Park: the South Lamma Country Park, south of Lo So Shing and excluding villages and residential areas, is one of the fourteen country parks proposed in the Territorial Development Strategy Review (Planning Department 1995).

Ÿ The waters to the west of Ha Mei Wan were identified in the Territorial Development Strategy Review as a ‘Significant Area’ for Marine Conservation (PELB 1998), as were the waters of the northern part of Tung O Bay.

Ÿ Identified as an ‘Unique Area’ for Marine Conservation (PELB 1998), the coastal waters of south Lamma are also a potential Marine Park. The potential South Lamma Marine Park would cover the waters south of Lo So Shing Beach, along the coastline of south Lamma, including Sham Wan, to the north boundary of Shek Pai Wan. Both hard and soft corals are known to occur here (Planning Department 1993). It lies over 2.5 km from the study area at its closest point.

Ÿ SSSI in Sham Wan: an area of 4 hectares including the sandy beach and the adjacent shallow shore in Sham Wan was designated as an SSSI on 3 June 1999. This area has been identified as important for Green Turtle Chelonia mydas nesting (Morton 1998).

Ÿ Restricted Area for green turtles in Sham Wan: The sandy beach of Sham Wan was designated on 30 July 1999 as a Restricted Area under the Wild Animals Protection Ordinance (Cap. 170), and is restricted for entry from 1 June to 31 October each year to protect breeding Green Turtles.

Ÿ South Lamma Island: south Lamma Island was designated as a Site of Special Scientific Interest (SSSI) in 1980. The objective was to protect the nesting habitats of White-bellied Sea Eagle Haliaeetus leucogaster and Bonelli’s Eagle Hieraaetus fasciatus near Mount Stenhouse.

8.7 No other designated, proposed or recognised sites of conservation importance lie within 5 km of the study area.

Literature Review

8.8 A literature review was conducted to provide information on existing conditions in the study area and Lamma Island, and to identify habitats and species of potential importance that may be affected by the Project. Literature review included Government and private sector

MAUNSELL Page 8/2 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

reports, independent and Government published literature and academic studies. Literature review included the following :

· Marine Ecology of Hong Kong: Report on Underwater Dive Surveys (October 1991 - November 1994) (Binnie 1995). Dive surveys at 86 sites in central and eastern Hong Kong waters; · EIA for Outlying Islands Sewerage Stage 1 Phase 1 (Maunsell 1997); · Hong Kong Bird Reports (1992-1998); · Porcupine! Numbers 1 - 27 (Newsletter of Department of Ecology & Biodiversity, University of Hong Kong); · Hong Kong Amphibians and Reptiles (Karsen et al. 1998); · WWF's 1:50000 Hong Kong Vegetation Map (Ashworth et al. 1993); · Aerial photos (CN20772-4 taken in 1998, CN18882-5 taken in 1997) from the Hong Kong Government Map Office; · Avifauna of Hong Kong (Carey et al. 2001); and · Memoirs of Hong Kong Natural History Society.

8.9 Results of the literature review are discussed in Section “Description of the Environment”.

Field Survey

8.10 Literature review was supplemented by field surveys. Field surveys were designed to fill data gaps which would prevent an adequate assessment of the project's impacts upon terrestrial, intertidal and subtidal ecology, and the development of appropriate mitigation measures. Four-season ecological surveys, including terrestrial flora survey, terrestrial fauna survey, avifauna survey, intertidal survey and dive survey, conducted between September 1998 to July 1999. A verification survey was conducted in April 2002 to update and verify the ecological data collected, and a coral mapping survey was performed in May 2002.

8.11 Sok Kwu Wan is a deep, rectangular embayment on the eastern coast of Lamma Island, lying southwest to northeast with its opening on the east side. The study area for ecology, based on the sewer alignment and the TM guideline setting the study area boundary 500m from the project boundary, was located south and east of Sok Kwu Wan including the shore line and the subtidal zone.

MAUNSELL Page 8/3 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Terrestrial Ecology

Field Survey Methodology

Habitats and Vegetation

8.12 Field surveys were performed on 22 September and 7 December 1998, and 19 March and 29 June 1999 to describe habitats and record plant species within the study area. Relative abundance of recorded plant species (common, occasional or rare) was also assessed. Sizes of each habitat type were estimated by manual grid count method. A verification survey was conducted in April 2002 to update habitats and species list. Efforts were made to find species protected under local regulations or known to be uncommon or rare on a regional or territorial basis. In this report, the conservation status of other plant taxa follows Xing et al. 2000.

8.13 A 1:5000 scale habitat map of the study area was produced based on 1997/8 Government aerial photographs, 1993 WWF's vegetation map and ground truthing.

8.14 Colour photographs were taken of all terrestrial habitat types surveyed and other features or species of conservation importance.

Stream and Aquatic Fauna

8.15 A main stream to the east of Ling Kok Shan flowed into the south of Sok Kwu Wan, a further incision of the embayment. The outlet portion had been channelled. Several smaller streams joined it in the outlet portion.

8.16 Surveys of aquatic fauna were conducted in the streams by active searching in March and June 1999. Fauna observed were identified to the lowest practicable taxon and recorded.

Birds

8.17 The bird communities of the terrestrial and coastal habitats in the study area were surveyed using the transect count method. Birds seen or heard within 25 m from the transect (1.75 km) (Fig. 8.2) were identified to species and counted. Surveys were carried out on 22 September (autumn survey), 7 December 1998 (winter survey), 19 March (spring survey) and 10 June 1999 (summer survey). Bird abundance was estimated as “birds ha-1”. Nomenclature, commonness and distribution of bird species in Hong Kong follows Viney et al. (1996), rarity and protection status of birds follows Zheng and Wang (1998). Results of birds in rocky shore habitats are reported in section “Inter-tidal Ecology” (Section 8.70).

Mammals, Reptiles, and Amphibians

8.18 Mammals, reptiles and amphibians in the study area were surveyed by active searching on 22 September (autumn survey), 7 December 1998 (winter survey), 19 March (spring survey) and 10 June 1999 (summer survey). Nomenclature for reptiles follows Karsen et al. (1998), that for amphibians follows Lau and Dudgeon (1999), and that for mammals follows Wilson

MAUNSELL Page 8/4 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

and Reeder (1992).

Invertebrates

8.19 Dragonflies and butterflies of the study area were surveyed by active searching on 22 September (autumn survey), 7 December 1998 (winter survey), 19 March (spring survey) and 10 June 1999 (summer survey). Nomenclature for dragonflies follows Wilson (1997) while that for butterflies follows Walthew (1997).

Results

8.20 The study area consists of natural coastline east from Sok Kwu Wan Village to Mo Tat Wan, a stream outlet to the western part of the bay and a vegetated coastal zone. Small disused quarries were also found to the east of the village.

8.21 Areas adjacent to the study area have suffered from environmental degradation due to noise and air pollution originating from Far East Cement quarry works, and marine pollution from the Fish Culture Zone. Other areas of degradation include the upland slopes east of Chung Mei Village which have been burnt as a result of graveside clearing.

Terrestrial Habitats and Vegetation

8.22 Terrestrial habitats within the study area include woodland, shrubland-grassland, cultivation, fishponds, disturbed/urbanised area and stream (Figure 8.2). The general environment and habitats had not changed as observed during the verification survey. The only changes noticed were the completion of construction of the Refuse Transfer Station at Sok Kwu Wan, and on-going construction at the coastal habitat of Lo So Shing. A total of 214 plant species were recorded (Appendix 8.1), about 20% of which are exotic species. No species protected under local regulations were recorded. Two uncommon tree species, Celtis biondii (Plate 8.9), Celtis timorensis (Plate 8.8), were recorded at the fringe of the woodland habitats along the hillside (Figure 8.2). These trees were described as “rare” and “restricted” respectively by Xing et al. (2000), but with increased records in recent years, they are therefore ranked as “uncommon”. "Important Habitats Where an Ecological Assessment Will Be Necessary" as listed in Note 2, Appendix A, Annex 16 of the EIAO-TM, existing on and near the terrestrial part of the study area, only include woodland habitat over 1 ha.

MAUNSELL Page 8/5 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Woodland

8.23 Woodland (a total of 5.1 ha) mainly occurred at Mo Tat Wan and Lo So Shing on the east and west ends respectively of the study area (Plate 8.1). 65 plant species were recorded in this habitat. It was composed of a mixture of native pioneer, plantation, and orchard plant species which in some places formed a closed canopy woodland. Acacia confusa and Casuarina equisetifolia were the dominant plantation species found. Native pioneer trees such as Ficus superba, Sterculia lanceolata, Celtis sinensis, Litsea glutinosa and Mallotus paniculatus were established within the plantation. Understorey was not well developed, and was composed of a variety of common species including Ilex asprella, Psychotria rubra, Breynia fruticosa, and Gardenia jasminoides. The woodland habitat within the study area is simple in structure and not mature. The 2 tree species of conservation importance, Celtis biondii and Celtis timorensis were recorded in this habitat.

Shrubland-grassland mosaic

8.24 23.8 ha of the study area was shrubland-grassland habitat, which occurs on most of the hillsides and along the backshore (Plate 8.2). Overall 144 plant species were recorded here, most of which are common and ruderal/pioneer species.

8.25 The hillsides within the study area were fairly eroded, and were dominated by mosaics of grasses, shrubs, large boulders, and bare earth. Pioneer native trees including Macaranga tanarius, Schefflera octophylla, Sterculia lanceolata, and Litsea glutinosa were commonly found along the footpath, while grasses (Isachne globosa, Miscanthus floridulus), shrubs (Rhodomyrtus tomentosa, Breynia fruticosa, Psychotria rubra, Trema orientalis), herbs (Dianella ensifolia, Caryopteris incana) and ferns (Dicranopteris linearis, Lygodium japonicum) were found on uplands.

8.26 The coastal and backshore community has poorly developed probably due to the steep terrain (bare rocky cliff surface), historical disturbance (construction of residential development, footpath, etc.) and on-going construction (e.g. reclamation of part of the coastline for construction of the Refuse Transfer Station). Other than the footpath, the coastline from Ta Shui Wan to Mo Tat Wan was fairly natural. The backshore community has poorly developed due to the steep terrain. Only a few individuals of species typical of the backshore community, including Hibiscus tiliaceus, Scaevola sericea, and Pandanus sp. were recorded. Other species recorded are common upland vegetation such as Sterculia lanceolata, Celtis sinensis, Bridelia tomentosa, Inula cappa, Zanthoxylum nitidum, which extended to the shore at the gullies. A few native grasses (Miscanthus floridulus, Neyraudia reynaudiana) and exotic weeds (Mikania micrantha, Lantana camara) were established on the sandy shore.

Cultivation

8.27 A few pockets of cultivated land (a total of 1 ha) were found within the study area (Plate 8.3). 15 plant species were recorded here. Most of them were abandoned and grown with weeds including Praxelis clematidea, Conyza canadensis, and Mikania mirantha. Remnant of crops (e.g. Colocasia esculenta) were also found. A few Banana (Musa paradisiaca), Sweet Potato (Ipomoea batatas) and Sugar-apple (Annona squamosa) were seen in active

MAUNSELL Page 8/6 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

fields.

Fishpond

8.28 Only one fenced fishpond was found within the study area at Sok Kwu Wan near village houses (Plate 8.5). This pond was small and abandoned. It still had open water while the pond bunds were grown with grasses and weeds including Panicum maximum and Micrantha micrantha. Due to the small size, proximity to urbanised area, and low plant diversity, it is of little ecological values.

Disturbed/urbanised area

8.29 The urban park near the pier and in the residential area constituted the disturbed/urbanised area (2.8 ha). A total of 34 plant species were recorded in this habitat; most were planted or exotic species. Other than the native tree Hibiscus tiliaceus, most plants were exotic landscaping or orchard species. Examples included Acacia confusa, Ficus elastica, Delonix regia, Psidium guajava and Dimocarpus longan. Considering the urbanised nature of the site and the plant species recorded in this habitat, this disturbed/urbanised area has little ecological value.

Stream and Aquatic Fauna

8.30 Freshwater streams in the study area were found to have little water flow during surveys, even in summer (Plate 8.6). Some of the streams had been channelled by local villagers.

8.31 The width of the streams varied from 0.5 m to about 1.5 m. The channelled portion was much wider, to the width of about 20 m, so the flow was slow and shallow. The stream bed of the channelled part was predominantly composed of coarse grained sand, probably as a result of upland erosion.

8.32 Diversity and abundance of aquatic fauna was limited. Abundant crabs Perisesarma bidens were seen on the banks of the streams. Fiddler crab Uca arcuata were found in the exposed sandy bed of the stream with their burrows. One individual of Varuna litterata was seen in the water. All these crab species are common and widely distributed in Hong Kong.

8.33 No aquatic species of rarity or conservation interest were found.

Birds

8.34 A total of 50 bird species were reported on Lamma Island between 1990 and 1997 by members of the Hong Kong Bird Watching Society and local naturalists (Appendix 8.2). There were 14 rare/endangered species (Table 8.1).

8.35 Aleutian Tern Sterna aleutica was recorded in West Lamma Channel in 1997 (Hong Kong Bird Watching Society pers. comm.). This species is fairly common in autumn though rare in spring in Hong Kong and it is primarily maritime (Carey et al. 2001).

MAUNSELL Page 8/7 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.1 Bird species of conservation importance on Lamma Island (from literature review)

Species Protection Status* Distribution Rarity Watercock - Low-lying freshwater Rare passage migrant habitats Woodcock - Woodland edge, usually Rare winter visitor along streams Black-eared Kite Class 2 Protected Animal of Found in many types of Common resident PRC and Appendix II of habitats CITES Crested Goshawk Class 2 Protected Animal of Usually found in wooded Rare resident PRC and Appendix II of habitats CITES Chinese Goshawk Class 2 Protected Animal of Usually in marshes or Rare passage migrant PRC and Appendix II of lightly-wooded hillsides CITES White-bellied Sea Eagle Class 2 Protected Animal of Hong Kong’s coastal areas, Uncommon/rare resident PRC and Appendix II of only recorded in Hong CITES Kong and nowhere else in China Bonelli’s Eagle Class 2 Protected Animal of Found in many types of Rare resident PRC and Appendix II of habitats, but usually in CITES lightly-wooded hillsides Kestrel Class 2 Protected Animal of Found in many types of Common/uncommon winter PRC and Appendix II of habitats visitor CITES Greater Coucal All birds are protected in Found in many types of Common resident Hong Kong, Class 2 habitats Protected Animal of PRC Lesser Coucal All birds are protected in Found in many types of Common resident Hong Kong, Class 2 habitats Protected Animal of PRC Hoopoe - Found in many types of Rare winter visitor habitats White’s Thrush - Found in many types of Uncommon/rare winter habitats visitor Hwamei Appendix II of CITES Found in shrubland Common resident habitats Grey Bushchat - Shrub covered hillsides Rare winter visitor and and cultivated lands passage migrant * All birds are protected in Hong Kong under Wild Animals Protection Ordinance (Cap. 170).

8.36 A total of 210 birds of 31 species were recorded in terrestrial habitats at the study area during field surveys between September 1998 and June 1999 (Appendix 8.3). Most species are common and widespread in Hong Kong and are typical of disturbed area (e.g., Chinese Bulbul Pycnonotus sinensis, Tree Sparrow Passer montanus). Mean bird abundance in the shrubland grassland mosaic was 11.9 birds ha-1, and was slightly higher than those from other shrubland in Hong Kong (4.7 – 7.4 birds ha-1) (Leven 2000). Mean bird abundance in the shrubland grassland mosaic was considered to be low to moderate. Six rare/endangered species were recorded in terrestrial habitats during the surveys (Table 8.2).

MAUNSELL Page 8/8 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.2 Bird species of conservation importance recorded at terrestrial habitats on the study area

Species Protection Status* Distribution Rarity Black-eared Kite Class 2 Protected Animal of Found in many types of Common resident PRC and Appendix II of habitats CITES Crested Goshawk Class 2 Protected Animal of Usually found in wooded Rare resident PRC and Appendix II of habitats CITES Black-winged - Found in many types of Rare winter visitor and Cuckoo-shrike habitats passage migrant Greater Coucal Class 2 Protected Animal of Found in shrubland Common resident PRC habitats Grey-streaked - Found in areas with some Uncommon/rare passage Flycatcher canopy cover migrant Hwamei Class 2 Protected Animal of Found in shrubland Common resident PRC habitats * All birds are protected in Hong Kong under Wild Animals Protection Ordinance (Cap. 170).

8.37 Four species showed signs of breeding during the spring and summer surveys in 1999. Nests of Barn Swallow Hirundo rustica and Black-necked Starlings Sturnus nigricollis were found in urbanised areas. Spotted Doves Streptopelia chinensis were observed mating and Magpie Robins Copsychus saularis were seen chasing intruders out of territories. These species are all common and widespread in Hong Kong (Viney et al. 1996), and build their nests in terrestrial habitats (e.g., urbanised areas, woodlands). A Black Drongo Dicrurus macrocercus nest was found on tree near the Refuse Transfer Station at Sok Kwu Wan in April 2002. This species is common and widespread in Hong Kong (ibid.).

8.38 Results of verification survey in April 2002 were compared to those in March 1999. No new species was recorded. There were only minor differences in both bird abundance and species richness. In addition, there were little changes in the terrestrial habitats (e.g., shrubland grassland mosaic) in the study area.

Mammals, Reptiles, and Amphibians

8.39 A mongoose, probably the Javan Mongoose Herpestes javanicus, was recorded in north Lamma, near Yung Shue Wan in 1996 (Anon 1996). This species was first recorded in Hong Kong in 1990, and its recorded range has expanded rapidly since then. Javan Mongoose, however, is recently considered as an introduced species (Corlett 2001). 8.40 Roosts of Japanese Pipistrelle Pipistrellus abramus (near Lo So Shing), Lesser Bent-winged Bat Miniopterus pusillus (near Sok Kwu Wan) and Bi-coloured Round-leaf Bat Hipposideros pomona (west slope of Mount Stenhouse) were recorded in Lamma Island (Ades 1999). All bats are protected in Hong Kong under the Wild Animals Protection Ordinance. Japanese Pipistrelle is probably the commonest bat in Hong Kong (ibid.). Lesser Bent-winged Bat is locally widespread but generally present in small numbers (ibid.). Bi-coloured Round-leaf Bat usually roosts in humid water catchment tunnels or flooded abandoned mines (ibid.).

8.41 Seven amphibian species have been recorded in Sok Kwu Wan between November 1991 and December 1996 (Lau and Dudgeon 1999). These were the Asian Common Toad Bufo

MAUNSELL Page 8/9 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

melanostictus, Gunther’s Frog Rana guentheri, Paddy Frog R. limnocharis, Romer’s Tree Frog Philautus romeri, Brown Tree Frog Polypedates megacephalus, Asiatic Painted Frog Kaloula pulchra and Ornate Pigmy Frog Microhyla ornata. All except Romer’s Tree Frog are common and widespread in Hong Kong (Lau and Dudgeon 1999).

8.42 The first record of the Hong Kong endemic Romer’s Tree Frog was from Lamma in 1952, and the species was rediscovered there in 1984 (Karsen et al. 1998). It has been recorded near caves and cultivated fields on the island, mostly near Sok Kwu Wan or south Lamma (ibid.). The species also occurs on several other islands, including Lantau and Po Toi (ibid.), and has then been introduced to Hong Kong Island and the New Territories. It is endemic to Hong Kong and is considered rare. Several conservation measures have been undertaken to protect the species, including according it protected status under the Wild Animals Protection Ordinance and implementing a reintroduction programme.

8.43 Records of snakes from Lamma include the Checkered Keelback Xenochrophis piscator and Bamboo Snake Trimeresurus albolabris, both seen near the beach to the east of the Hong Kong Electric Power Station in the north of the island (Anon. 1997). Other snakes also recorded near Yung Shue Wan include the Plumbeous Water Snake Enhydris plumbea and Taiwan Kukri Snake Oligodon formosanus (Anon. 1996). The Burmese Python Python molurus bivittatus was recorded on Lamma Island (Karsen et al. 1998). This species is protected by law in Hong Kong (ibid.), listed in Appendix II of CITES and is a Class I protected species of the PRC (Zhao 1998).

8.44 Three-banded Box Terrapin Cuora trifasciata, a rather rare forest stream species, was found on Lamma Island (Karsen et al. 1998). This species is only known from a few locations in Hong Kong (ibid.). Three-banded Box Terrapin is a Class II protected species of the PRC and is considered as “endangered” by IUCN (Zhao 1998). All terrapins are protected in Hong Kong under the Wild Animals Protection Ordinance.

8.45 An unidentified sea turtle was reported off the SE coast of Lamma Island on 7 May 1998 (Anon. 1998). Most local sightings of sea turtles are of the Green Turtles Chelonia mydas. Green Turtle is considered as “endangered” by IUCN, listed in Appendix I of CITES and is a Class II Protected Animal of PRC (Zhao 1998). Green Turtle used to nest regularly on Lamma Island, usually between July and August (Karsen et al. 1998). Sham Wan on southern Lamma is the only currently known nesting site of Green Turtle in Hong Kong (Anon. 1998). Due to illegal collection of its eggs and also to deterioration of the marine habitats, the local population of Green Turtles is seriously under threat (Karsen et al. 1998). Local villagers indicated that there had been about 20-50 nestings in Sham Wan per season but the number has dropped over the last decade (McGilvray and Geermans 1997). There was only one turtle reported to have laid eggs in 1996 and none in 1997 (ibid.) but nesting was confirmed in 1998. The beach at Hung Shing Ye on western Lamma had been used by nesting turtles until twenty years ago when increasing human inhabitation drove nesting turtles away (Anon. 1998). Another record of sea turtles was the shell of a Pacific Ridley Turtle Lepidochelys olivacea found washed ashore on a beach in south-west Lamma Island (ibid.). All sea turtles are protected in Hong Kong under the Wild Animals Protection Ordinance.

MAUNSELL Page 8/10 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8.46 Reptile and amphibian species of conservation importance reported in Lamma Island are summarised in Table 8.3.

MAUNSELL Page 8/11 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.3 Summary of reptile and amphibian species of conservation importance in Lamma Island (from literature review)

Species Protection Status* Distribution Rarity Burmese Python Protected by law in Hong Widely distributed in Abundance in China Kong; Hong Kong, found in a declining Class I protected species variety of habitats of the PRC; Appendix II of CITES Three-banded Box Protected by law in Hong Only known from a few Rare in Hong Kong and Terrapin Kong; localities in Hong Kong, China, due to over- Class II protected species Found in hill and exploitation of the PRC mountain streams in the vicinity of broad-leaf woodland or secondary forest Green Turtle Protected by law in Hong Occurs in marine waters Rare, under threat due to Kong; around Hong Kong illegal collection of eggs Class II protected species except in the west and deterioration of of the PRC; marine environment Appendix I of CITES Romer’s Tree Frog Protected by law in Hong Lamma Island, Po Toi, Restricted, endemic Kong Lantau Islands

8.47 No amphibian or mammal was observed in the study area during the field surveys between September 1998 and June 1999. Reeves’ Terrapins Chinemys reevesii and Red-eared Sliders Trachemys scripta were found in a small pond near the estuary during the spring and summer surveys in 1999. Reeves’ Terrapin is primarily an inhabitant of ponds and rivers (Karsen et al. 1998). This species is once common throughout its range, but now become rare due to over-exploitation as food and medical uses (Zhao 1998). Red-eared Slider is an introduced North American species (Karsen et al. 1998). No changes which would have implication on herpetofauna diversity were observed during the verification survey in April 2002.

8.48 Recently, in an ecological survey for a separated project within the study area of the present proposed Project, calling of 6 male Romer’s Tree Frogs was reported in a small moist area of shrubland/grassland habitat near the Pumping Station P2 site (Halcrow China Limited 2002) (see Figure 8.8). Assessment of potential impacts on this species is provided in Section 8.114 below.

Invertebrates

8.49 There was no previous record of dragonflies at the study site. Two dragonfly species were recorded at the site during the field surveys. These were Orthetrum sabina and Pantala flavescens. Both are common and widespread, and can be found in a wide range of habitats in Hong Kong (Wilson 1995, 1997). These two species were observed again during the verification survey in April 2002.

8.50 Twenty-one butterfly species were reported (P. K. L. Lau, pers. comm.) in the shrubland/grassland mosaic habitats at the study area between 1998 and 1999 (Table 8.4).

MAUNSELL Page 8/12 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

This total included 6 rare and 10 uncommon species, including the protected species Birdwing Troides helena.

8.51 Nineteen butterfly species were recorded in the study area during field surveys (Table 8.5). All are common or very common in Hong Kong (Walthew 1997).

8.52 Two more butterfly species were recorded in April 2002. These were the Tawny Rajah Charaxes polyxena and Common Sailor Phaedyma hylas. Both are common in Hong Kong (Walthew 1997). The verification survey in April 2002 revealed little change in the habitats of butterflies in the study area between 1998 and 2002. The two dragonfly species recorded in the study area in 1998, were also recorded during the verification survey in April 2002.

Table 8.4 Additional butterfly species reported in the study area between 1998 and 1999 (P. K. L. Lau, pers. comm.).

Common name Latin name Abundance Striped Blue Crow Euploea mulciber UC Hong Kong Cupid Everes lacturnus C Cornelian Deudorix epijarbas R Long-banded Silverline Spindasis lohita UC Small White Artogeia rapae R Orange Awlet Bibasis oedipodea R Baron Euthalia phemius UC Grey Pansy Junonia atlites C Lemon Pansy Junonia lemonias UC Blue Pansy Junonia orithya UC Grass Demon Udaspes folus R Red Admiral Vanessa indica UC Painted Lady Vanessa cardui R Hong Kong Lacewing Cethosia biblis UC Hong Kong Fritillary Argyreus hyperbius VC Swallowtail Papilio xuthus UC Chinese Peacock Papilio bianor C Fivebar Swordtail Graphium antiphates C Golden Birdwing Troides aeacus R Birdwing Troides helena UC Yellow Orange Tip Ixias pyrene UC Abundance: C = common, VC = very common, UN = uncommon, R = rare (Walthew 1997)

Table 8.5 Butterfly species recorded in the study area during field surveys.

Common name Latin name Abundance Common Faun Faunis eumeus C Blue Glassy Tiger Ideopsis similes VC Dark Veined Tiger Danaus genutia VC Blue Spotted Crow Euploea midamus VC Common Lascar Pantoporia hordonia C

MAUNSELL Page 8/13 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Common name Latin name Abundance Great Eggfly Hypolimnas bolina C Short-banded Sailor Phaedyma columella C Angled Castor Ariadne ariadne C Punchinello Zemeros flegyas C Paris Peacock Papilio paris VC Red Helen Papilio helenus VC Common Mormon Papilio polytes VC Tailed Green Jay Graphium agamemnon VC Great Orange Tip Hebomoia glaucippe C Common White Artogeia canidia VC Common Black Jezebel Delias pasithoe C Common Grass Yellow Eurema hecabe VC Common White-banded Brown Lethe confusa C Dark Brand Bush Brown Mycalesis mineus VC Abundance: C = common, VC = very common, UN = uncommon, R = rare (Walthew 1997)

8.53 The ecological importance of the habitats identified was evaluated against the criteria in Annex 8 of the EIAO-TM.

Evaluation of Woodland within the Study Area

Criteria Discussion Naturalness A mixture of planted and native species Size 5.1 ha Diversity Moderate plant species diversity, low to moderate for fauna Rarity Two uncommon tree species, Celtis biondii and Celtis timorensis. Three uncommon/rare bird species, Crested Goshawk Accipiter trivirgatus, Black-winged Cuckoo-shrike and Grey-streaked Flycatcher Muscicapa griseisticta. Re-creatability Moderately difficult to create in terms of species composition Fragmentation Patchy, surrounding villages Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Moderate with management such as fire control Nursery/Breeding Ground No record of significant nursery or breeding ground during the surveys. But could provide breeding habitats for birds, mammals and butterflies. Age Young Abundance/Richness of Low to moderate Wildlife Overall Ecological Value Moderate

Evaluation of Shrubland/Grassland within the Study Area

Criteria Discussion Naturalness Natural in general, with exception at backshore which are modified by development Size Large continuous patch on upper hillslopes within the Study Area. The total size of this habitat is approximately 23.8ha. Diversity Moderate to high plant species diversity, low fauna diversity Rarity Three uncommon/rare bird species, Crested Goshawk Accipiter trivirgatus, Black- winged Cuckoo-shrike and Grey-streaked Flycatcher Muscicapa griseisticta. The endemic anuran species Romer’s Tree Frog Philautus romeri was reported by another study. Re-creatability This habitat can be re-created, but some native species are not commercially available Fragmentation Less fragmented

MAUNSELL Page 8/14 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Criteria Discussion Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Moderate, become secondary woodland over time, but limited by fire disturbance Nursery/Breeding Ground Romer’s Tree Frog calling was reported by a separated study (see Figure 8.8). This habitat in general also provides breeding habitats for birds, mammals and butterflies. Age Young Abundance/Richness of Low wildlife richness and abundance Wildlife Overall Ecological Value Low (*excluding the small moist area used by Romer’s Tree Frog in Figure 8.8 which has moderate to high Overall Ecological Value)

Evaluation of Cultivated Lands within the Study Area

Criteria Discussion Naturalness Human-created habitat but abandoned, mostly with remnants of crops or weedy species. Size About 1 ha Diversity Low plant diversity. Rarity None recorded Re-creatability This habitat can be readily re-created Fragmentation Isolated pockets in the Study Area Ecological Linkage Not functionally linked to any highly valued habitat in close proximity. Potential value Low Nursery/Breeding Ground No record of significant nursery or breeding ground during the surveys. Age Young Abundance/Richness of Low Wildlife Overall Ecological Value Low

Evaluation of Fishponds within the Study Area

Criteria Discussion Naturalness Human-created but abandoned. Size About 0.1ha Diversity Low species diversity Rarity Low fauna diversity. Re-creatability This habitat can be readily re-created. Fragmentation Isolated within the Study Area. Ecological Linkage Not functionally linked to any highly valued habitat in close proximity. Potential value It could become mangroves/marsh habitat over time if left unmanaged. Nursery/Breeding Ground No record of significant nursery or breeding ground during the surveys. Age Young Abundance/Richness of Low Wildlife Overall Ecological Value Low

Evaluation of Streams within the Study Area

Criteria Discussion Naturalness Natural at upper reach, modified sections can be found at middle or lower reaches Size The total length of the freshwater streams is about 700m Diversity Low aquatic invertebrate species and other wildlife diversity Rarity One uncommon bird species, Yellow Bittern Ixobrychus sinensis. Re-creatability Difficult to be re-created

MAUNSELL Page 8/15 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Criteria Discussion Fragmentation Not applicable Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Medium, more aquatic species could establish if given time Nursery/Breeding Ground Not functionally linked to any highly valued habitat in close proximity Age No information but considered irrelevant Abundance/Richness of Low Wildlife Overall Ecological Value Low

Evaluation of Urbanised Area within the Study Area

Criteria Discussion Naturalness Low. Heavily disrupted and disturbed by human activities Size The total size of this habitat is approximately 2.8ha Diversity Low plant diversity Rarity Neither rare nor protected species recorded during the surveys Re-creatability This habitat can be readily re-created Fragmentation Heavily fragmented Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Low Nursery/Breeding Ground No record of significant nursery or breeding ground during the surveys. But can provide nesting habitat for some disturbance tolerant bird species. Age No information but considered irrelevant Abundance/Richness of The abundance and richness of wildlife recorded were low Wildlife Overall Ecological Value Low

Intertidal Ecology

8.54 The natural coastline along the south shore of Sok Kwu Wan varies between an estuarine environment to the west of Sok Kwu Wan and a granite boulder/cliff shoreline to the east of Sok Kwu Wan.

8.55 Intertidal "Important Habitats Where an Ecological Assessment Will Be Necessary" listed in Note 2, Appendix A, Annex 16 to the TM existing on and/or near the study area only include undisturbed natural coastline over 1 ha or 500 m, on the south shore of Sok Kwu Wan.

8.56 An intertidal sand flat is located at the southern end of Sok Kwu Wan, in front of Chung Mei Village, about 17,000 m2 in area, between the outlet of the channelled streams and the subtidal area of the bay (Plate 8.4).

8.57 The natural rocky shore close to the outfall and the sand flat outside the outlet of the streams were identified as having ecological value and were surveyed.

Field Survey Methodology

Rocky shores

MAUNSELL Page 8/16 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8.58 Preliminary field surveys were undertaken on 22 and 23 September 1998. It was found that Outfall Option 1 was located on steep bedrock and could not be reached from either sides or above. Given that the distance between the two Outfall Option was less than 250 m and their substrate type was similar, data from Outfall Option 2 could represent the condition of the nearby shore, including Outfall Option 1. Therefore quantitative field surveys were conducted on 10 December 1998, 19 March 1999 and 29 June 1999 on the intertidal rocky shore community near Outfall Option 2 on the south shore of Sok Kwu Wan. The slope was steep bedrock contained large granite boulders. The shores are open to weather influences from the north Lamma Channel and to disturbance by shipping wakes and can therefore be regarded as semi-exposed.

8.59 The intertidal flora and fauna were described through the use of belt transect method. A single transect was laid across the intertidal zone in the natural shorelines (Fig.8.2). The transect covered the wave splash level (0 m transect station) down to the sublittoral fringe. The low tide during the sampling period averaged 0.6 mPD. Tide readings were taken from nearby Chi Ma Wan tide station. At 2 m intervals a quadrat measuring 0.25 m2 (0.5 m x 0.5 m) was placed along the transect on the rock surface. All fauna within the quadrat were counted and identified to the lowest taxon possible, and an estimate of percentage cover of macroalgae along grid lines within the quadrat was made by naked eye. Sample specimens of fauna not identified in the field were taken to the laboratory for further analysis. Special attention was paid for any species of conservation importance.

8.60 The bird community on the rocky shore was studied using the transect count method (Fig. 8.2). A 1.75 km transect was run on the study area. Birds seen or heard within 20 m from the transect were identified to species and counted. Records of bird sightings is listed in Appendix 8.3. Nomenclature followed Viney et al. (1996). Counts were carried out on 22 September (autumn survey) and 7 December 1998 (winter survey), and 19 March (spring survey) and 10 June 1999 (summer survey).

Sandflat

8.61 Active searches of fauna were conducted on the sandflat in 20 March, 29 June and 14July 1999. Sightings of epifauna were recorded and identified to the lowest practicable taxon.

Results

Rocky Shore

8.62 The intertidal community on the rocky shore studied was similar to those found on other semi-exposed coastlines in Hong Kong. Species recorded are listed in Table 8.6. Fauna which typically inhabit both exposed and sheltered shores were found in the study site.

8.63 Near the Outfall Option 2, fauna recorded on the rocky outcrops included three littorinid snails in the littoral fringe: Littorina scabra, Littorina brevicula and Nodilittorina millegrana (Morton and Morton 1983).

8.64 Fauna of both wave exposed shores, such as Grapsus albolineatus (Crustacea, Brachyura),

MAUNSELL Page 8/17 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Eriphia smithii (Crustacea, Brachyura) and Septifer bilocularis (Bivalvia, Lamellibranchia), and boulder shores, such as Polycheir rufescens (Echinodermata, Holothuroidea), Petrolisthes japonicus (Crustacea, Anomura) and Gaetice depressus (Crustacea, Brachyura), were found.

8.65 Strong seasonality was shown by macroalgae. Sargassum sp. floated along the coastline in spring and Ulva sp. grew on low intertidal rock surfaces. Both were abundant.

8.66 No fauna known to be rare was found during surveys. Overall the fauna appeared to be lacking in diversity and abundance. As with most shores of Hong Kong, zonation patterns were evident.

8.67 Results of the four seasonal surveys are provided in Table 8.7-8.10. Beside the obvious zonation pattern, a trend of increase in abundance from winter to summer is also shown in the results. The significant increase in algae abundance in spring 1999 is also consistent with the seasonal growth pattern of algae in Hong Kong.

Table 8.6 Flora and fauna found along the rocky shore of Sok Kwu Wan

Phylum/Class Scientific name Common name Algae Lithophyllum sp. Pink crust algae Corallina pilulifera Red turf algae Porphyra suborbiculata Red algae Sargassum sp. Brown algae Ulva sp. Green algae Amphineura Acanthopleura japonica Chiton Bivalvia Septifer bilocularis Black mussel Saccostrea cucullata Rock oyster Gastropoda Cellana toreuma Limpet Patelloida saccharina Limpet Littorina scabra Snail Littorina brevicula Snail Nodilittorina millegrana Snail Nodilittorina pyramidalis Snail Thais clavigera Snail Monodonta labio Snail Nerita albicilla Snail Lunella coronata Snail Crustacea Tetraclita sp. Barnacle Ligia exotica Sea slater Petrolisthes japonicus Porcelain crab Eriphia smithii Crab Gaetice depressus Crab Grapsus albolineatus Crab Nanosesarma minutum Crab Echinodermata Polycheir rufescens Sea cucumber Species richness 26

MAUNSELL Page 8/18 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.7 Intertidal fauna and algae recorded on preliminary surveys at Sok Kwu Wan, September 1998

Scientific name Common name Lithophyllum sp. Pink crust algae Corallina pilulifera Red turf algae Porphyra suborbiculata Red algae Acanthopleura japonica Chiton Cellana toreuma Limpet Patelloida saccharina Limpet Nodilitorina pyramidalis Snail Nodilittorina millegrana Snail Thais clavigera Snail Species richness 9

Table 8.8 Abundance of intertidal fauna and percent cover of algae inside quadrats long the transect near Outfall Option 2 in winter 1998

Scientific name Station S1 (0 m) Station S2 Station Station S4 (6 m) High Tide (2 m) S3 (4 m) Low Tide Nodilittorina pyramidalis 6 1 Nodilittorina millegrana 8 Thais clavigera 7 4 1 Acanthopleura japonica 3 Patelloida saccharina 1 Lithophyllum sp. 15% Corallina pilulifera 20% Total species richness 7 Total abundance 30

Table 8.9 Abundance of intertidal fauna and percent cover of algae inside quadrats along the transect near Outfall Option 2 in spring 1999

Scientific name Station S1 (0 m) Station S2 Station Station S4 (6 m) High Tide (2 m) S3 (4 m) Low Tide Nodilittorina pyramidalis Nodilittorina millegrana 10 Thais clavigera Monodonta albio 3 1 Nerita albicilla 1 Saccostrea cucullata 25 Acanthopleura japonica 1 Patelloida saccharina 8 50 Lunella coronata 1 Ulva sp. 10% 30% Lithophyllum sp. 15% 10% Corallina pilulifera 5% 10% Total species richness 12 Total abundance 100

MAUNSELL Page 8/19 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

MAUNSELL Page 8/20 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.10 Abundance of intertidal fauna and percent cover of algae inside quadrats along the transect near Outfall Option 2 in summer 1999

Scientific name Station S1 (0 m) Station S2 Station Station S4 (6 m) High Tide (2 m) S3 (4 m) Low Tide Nodilittorina pyramidalis 16 Nodilittorina millegrana 17 Thais clavigera 6 Acanthopleura japonica 2 1 Tetraclita sp. 17 110 Monodonta albio 9 1 Setifer bilocularis 2 Patelloida saccharina 50 Saccostrea cucullata 140 100 Nerita albicilla 4 Lunella coronata 6 Lithophyllum sp. 30% Corallina pilulifera Total species richness 13 Total abundance 474

8.68 Intertidal surveys were carried out for the feasibility study of the Western Coast Road (ERM, 1998) during 1997. The quantitative survey was undertaken in Chiu Keng Wan on the inter- tidal rocky shore community along the alignment of P2 Road in Junk Bay. Similar to other hard shores in Hong Kong, a clear vertical zonation pattern was evident through community structure. Table 8.11 summarises the result of the Western Coast Road survey. 29 species of flora and fauna were recorded. The species richness recorded was similar with that in the present survey (26 in Table 8.6).

Table 8.11. Summary of Species Identified Along Shoreline of Chiu Keng Wan During Preliminary Field Surveys (ERM, 1998)

Species Abundance Zone Low-shore Mid-shore High-shore Mobile Fauna Littorinids Nodillittorina trochoides Low to moderate X X Nodillittorina radiata Moderate to high X X Nodillittorina vidua Moderate to high X X Littoraria articulata Low X X Peasiella roepstorffiana Low X X Topshells Chlorostoma Low X argyrstomus Lunella coronata Low X X Nerita albicilla Low X Monodonta labio Low X Limpets Cellana grata Low X Cellana toreuma Moderate X

MAUNSELL Page 8/21 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Species Abundance Zone Low-shore Mid-shore High-shore Patelloida saccharina Moderate to high X X Patelloida pygmaea Low to moderate X X Siphonaria sirius Low X X Siphonaria japonica Low X Chiton Acanthopleura japonica Moderate X X Dogwhelks Thais clavigera Moderate X Morula musiva Low X Bivalves Barbatia virescens Low X Septifer virgatus Low X Saccostrea cucullata Low to moderate X X Barnacles Tetraclita sp. High X X Capitulum mitella Low X X Sea anemone Unknown sp. Low X Algae Ralfsia expansa High X Hildenbrandtia High X prototypus Green turf High X Encrusting coralline High X Kyrthrix maculans Moderate X

8.69 A verification survey for intertidal habitats was performed in April 2002 to verify the data from surveys in 1998 to 1999. No significant changes were found in the intertidal hard- surface habitat. The composition species and their densities of the rocky shore communities matched with the finding of the surveys in 1998 to 1999. No algae were found on the intertidal rocky surface, though Sargassum was seen in the shallow subtidal zone just seaward to the study site.

Table 8.12 Abundance of intertidal fauna inside quadrats along the transect near Outfall Option 2 in 2002

Scientific name Station S1 (0 m) Station S2 Station Station S4 (6 m) High Tide (2 m) S3 (4 m) Low Tide Nodilittorina pyramidalis 10 Nodilittorina millegrana 8 Thais clavigera 3 Tetraclita sp. 21 88 Monodonta albio 2 10 2 Setifer bilocularis 3 Patelloida saccharina 36 Saccostrea cucullata 110 85 Nerita albicilla 1 1 Lunella coronata 5 Total species richness 10

MAUNSELL Page 8/22 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Scientific name Station S1 (0 m) Station S2 Station Station S4 (6 m) High Tide (2 m) S3 (4 m) Low Tide Total abundance 385

8.70 A total of 94 birds of 12 species were recorded on the rocky shores (Appendix 8.3). Most species recorded on the rocky shore are habitat generalist and are typical of disturbed area (e.g., Crested Myna Acridotheres cristatellus, Tree Sparrow). Two species of conservation importance were recorded and these were the Reef Egret Egretta sacra and Black-eared Kite. Black-eared Kite is habitat generalist, while Reef Egret is more dependent on rocky shore. The conservation importance of these two species are shown in Table 8.12b.

Table 8.12b Bird species of conservation importance recorded at rocky shore on the study area

Species Protection Status* Distribution Rarity Black-eared Kite Class 2 Protected Animal of Found in many types of Common resident PRC and Appendix II of habitats CITES Reef Egret Class 2 Protected Animal of Usually found in coastal Uncommon/rare resident PRC areas

Sandflat

8.71 At low tide, the sand flat was exposed and with only limited sheet flows, to the seaward side (Plate 8.4). Wastewater from nearby restaurants and residential areas would be discharged into the sand flat. The high organic content of the substratum was shown by the black coloration of the subsurface sediments.

8.72 Numerous burrows were scattered on the sand flats, mainly belonging to crabs including Uca borealis, Uca lactea and Uca arcuata. Scylla serrata, Scorpimera sp. and Macrophthalmus sp. were also found here. Fauna composition is similar with those in other sandflat habitats in Hong Kong such as Starfish Bay in Ma On Shan (Morton & Morton 1983). Uca species, Scorpimera sp. and Macrophthalmus sp. showed a zonation distribution on the sandflats in both Sok Kwu Wan and Starfish Bay.

8.73 Within the sheet flows on the east of the sand flat, small horseshoe crabs Tachypleus tridentatus (Plate 8.7) was found both on the surface and semi-buried in June and July 1999. 22 individuals were counted in the summer survey, ranging from 3-5 cm in prosoma breadth.

8.74 A verification survey was conducted in April 2002 to verify the data collected in 1998 to 1999. The ecological conditions of the sandflat in 2002 have not significant changes with 1998. The fauna recorded also matched with the previous field survey results. However, no horseshoe crabs were recorded in 2002 survey. Horseshoe crabs are more numerous in Hong Kong’s western waters whilst records in eastern waters are only sporadic. Chiu & Morton (1999) observed Tachypleus tridentatus adults from East Lamma Channel, though, Sok Kwu Wan was not on the list of the 27 sites where horseshoe crab were recorded during their study period. There is no evidence to demonstrate that Sok Kwu Wan is regularly utilised by horseshoe crabs.

MAUNSELL Page 8/23 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Evaluation of Intertidal Habitat within the Study Area

Criteria Discussion Naturalness Moderate. Disturbed by pollution loading and previous coastal development Size About 2.8km coastline Diversity Low fauna diversity Rarity Juvenile Horseshoe crabs were recorded on the sandflat during the surveys Re-creatability This habitat is difficult to re-create Fragmentation Partially fragmented Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Moderate Nursery/Breeding Ground Juvenile Horseshoe crabs were recorded on the sandflat in 1999, but not found in 2002. Age No information but considered irrelevant Abundance/Richness of The abundance and richness of wildlife recorded were low Wildlife Overall Ecological Value Moderate

Subtidal Ecology

8.75 Subtidal "Important Habitats Where an Ecological Assessment Will Be Necessary" listed in Note 2, Appendix A, Annex 16 to the TM existing on and/or near the study area include established coral communities at Pak Kok, about 3.5 km north of the study area, at Luk Chau, about 1.5 km north of the study area (Binnie 1993), and at Sham Wan about 2 km south of the study area (Planning Department 1993).

8.76 None of these areas is immediately adjacent to the study area. No information about the coral communities inside Sok Kwu Wan was available. To find out the conditions of the coral communities within the study area, diving surveys were conducted.

Field Survey Methodology

8.77 Two sites were selected for dive surveys on coral communities (Figure 8.2). Site 1 was near Outfall Option 1 and site 2 was near Outfall Option 2. Dive surveys were completed in December 1998. Dives were conducted along both optional outfall alignments.

8.78 Underwater quantitative surveys along both proposed alignments were completed on 2 December 1998. At each option (Option 1: N: 22 12 552, E 114 08 556 / Option 2: N 22 12 564, E 114 08 403) a line transect was run out at a bearing relating to the angle of the alignment. A 50 m line was laid and 10 m transects were performed at 0 – 5 meter and 45- 50 meter distance from the shoreline.

8.79 Video transects were recorded at each of the two survey sites. The transects were laid parallel to the shore and following an approximate depth contour. At each site transects were laid in two distinct depth zones: 0-3m and 4-7 m below C.D. Four transects were recorded at the shallow depth zone and two transects at the deeper depth zone.

8.80 Each transect was filmed at approximately 40cm above the substrate and at a rate of approximately 75 seconds (a rate of 15-20 cm per sec). The video recorded a 40cm swath of

MAUNSELL Page 8/24 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

coral (seabed) from a height of approximately 40cm. The video camera was held perpendicular to the substrate to minimise parallax error and to keep the substrate in focus. Each set of video footage from each site was copied from Hi8 to VHS after editing.

8.81 The video transect was played back on an ordinary TV monitor. Each transect was paused at fixed timed intervals of three seconds at individual video frames and a number of points sampled. A fixed time interval of three seconds was used between video frames to ensure no overlap between frames. The video transects were sampled using a random point sampling method. Fixed random co-ordinates were marked on an acetate sheet which was placed in front of the TV screen. The points were used as reference marks from which to identify the hard coral species abundance. Approximately 22-25 video frames per 10 m transect were obtained for a total of 110-125 points per transect

8.82 Each 10m video transect yielded 22-25 video frames, for a total of 110-125 points per transect. The point count data were used to calculate percent cover for each site. Since this and similar sampling methods tends to be biased against the inclusion of rare species, presence-absence data were also gathered for coral species by viewing the entire videotape of each transect.

8.83 A further coral mapping survey was conducted in May 2002 to record the locations and number of coral colonies in the subtidal area of Outfall Option 1 (Site 1), which was considered to have higher potential on being selected as the preferred option during the EIA.

8.84 The main objectives of this work were to record the species number, locations and sizes of coral colonies along the alignment and within the dredging area of Outfall Option 1., and to identify potential translocation sites on the nearby coastline to facilitate a translocation plan where necessary.

8.85 The survey included three parts: 1) A quantitative dive survey to count and record the coral colonies (hard and soft) in terms of their species, size, abundance, distribution and ecological significance, or species of conservation importance within the dredging area; 2) To capture underwater video transects and benthic cover/ecological attributes of four major transects; and 3) To identify potential translocation sites. This survey also verified the findings from the previous dive survey conducted in 1998.

8.86 1) Coral mapping at Outfall Option 1: A transect with scale was deployed along the outfall alignment (Main transect) as indicated on Figure A8.5-1 in Appendix 8.5. The Main transect extended for 50 m. The exact location of the starting point of the Main Transect was determined with a portable Global Positioning System (GPS). Starting from 1m distance on the Main transect, transects parallel to the coastline (Parallel transect) were deployed at 2m intervals. The Parallel transects extended 17m from both sides of the Main transect, thus covering a width of 34m to ensure a complete coverage of the dredging area (33m in width). The total number of Parallel transects was 25. Within 1m on either side of each Parallel transect, the locations of any coral colonies (both hard and soft) found were recorded with reference to the Parallel transects and Main transect. A specific code was assigned to each colony recorded. Their sizes and the sizes of the boulders on which they colonise were also estimated and recorded. Photographs of representative coral colonies located in the surveyed areas were taken using an underwater camera. Results were presented as a map showing the

MAUNSELL Page 8/25 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

locations of all coral colonies within the dredging area. The total number of coral colonies, their sizes and the sizes of the boulders beneath were also provided according to their assigned codes.

8.87 2) Video recording and ecological assessment at Outfall Option 1 Video transects were recorded on the Main transect and three of the Parallel transects in which most coral colonies were recorded. Each transect was filmed at approximately 40cm above the substrate and at a constant speed in compliance with standard protocols for coral surveys (no more than 10 metres per minute). The video camera was held perpendicular to the substrate to minimise parallelax error and to keep the substrate in focus. The video transects recorded a 40cm swath of seabed The video for the Main transect showed the zoning of seabed substrate along the outfall alignment, and also the distance of the band in which most corals could be found. Video tapes for the parallel transects showed whether there was any change of coral colony density along the coastline within the dredging area. The video tapes of Parallel transects were also used to rectify the locations of coral colonies recorded in the field. The present conditions of coral colonies were recorded on site and extracted from the video transects. Information concerning the physical nature of Outfall Option 1 were recorded during the survey. This information consisted of observations regarding the degree of exposure of the site to wave action, the nature of the substrate type and the topographic profile of the site. In addition to video recording, the benthic cover and ecological attributes of the above 4 major transects were recorded following the Rapid Ecological Assessment (REA) technique.

8.88 3) Identification of potential translocation sites Bound dives were conducted along the coastline between Mo Tat Wan and Sok Kwu Wan. Two location suitable for translocation purpose were identified and recorded on maps. The conditions of the subtidal habitats, as well as the marine ecological assemblages, especially the present conditions of any exiting coral colonies, in the vicinity of the potential translocation sites were recorded with the provision of video samples and/or photographs. Information concerning the physical nature of the potential translocation sites was also recorded. This information included the degree of exposure of the sites to wave action, the nature of the substrate types and the topographic profiles of the sites.

Results

Site 1

8.89 Raw data from the coral surveys are provided in Appendix 8.4. The boulder sublittoral extended approximately 20 m from the shoreline and was wider than that at site 2. Hard coral cover was marginally higher and consisted of more species. Hard corals were also observed at lower depths (3-4m below CD). In total 13 species were recorded (Table 8.13) and coral cover was less than 5% (mean 2.26%) (Figure 8.3). Approximately 8 m out from the shore a band of dead standing coral was observed. The dead coral was the remnants of several Pavona descussata stands.

MAUNSELL Page 8/26 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.13 Coral species recorded at Site 1, December 1998

Family Species Dendrophylliidae Turbinaria peltata Faviidae Cyphastrea sp Faviidae Favia lizardensis Faviidae Favia speciosa Faviidae Favites abdita Faviidae Favites flexuosa Faviidae Favites pentagona Faviidae Goniastrea aspera Faviidae Hydnophora exesa Faviidae Platygyra sinensis Faviidae Plesiastrea versipora Poritidae Goniopora stutchburyi Poritidae Goniopora columna

8.90 Further out from the shoreline, the seabed consisted of scattered small boulders and eventually at 30-40 m out from the shoreline the seabed was composed mainly of fine sand/silt with isolated patches of shell fragments. Three Pteroeides sp. (sea pens) were also observed.

Site 2

8.91 This site was nearer to the Fish Culture Zone (Figure 8.2) Hard coral cover was restricted to a narrow band of boulder substrate, approximately 5 m in width and not more than 1.5 m below CD. Coral cover was estimated at less than five percent (mean 2.75%) (Figure 8.4), and eight species of scleractinian coral were observed (Table 8.14).

Table 8.14 Coral species recorded at Site 2 in December 1998

Family Species Dendrophylliidae Turbinaria peltata Faviidae Cyphastrea sp. Faviidae Favia lizardensis Faviidae Favites pentagona Faviidae Favia speciosa Faviidae Goniastrea aspera Faviidae Plesiastrea versipora Faviidae Platygyra sinensis

8.92 Once the hard substrate ended the benthic substrate consisted of silty sand and was devoid of marine life. One large concrete block (1 m3) was located at roughly 4m depth near the Fish Culture Zone; the concrete appeared to act as an artificial reef, as several colonies of Dendronephthya sp. were seen attached to the upper surface of the block.

8.93 Site 1 possessed more species of hard coral and slightly lower coverage (2.26 %), though, the hard coral cover in Site 2 (2.75 % coverage) was still low relative to major coral communities within Hong Kong’s waters. This site did exhibit evidence of disturbance with

MAUNSELL Page 8/27 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

dead stands of Pavona descussata, however, several small (juvenile) coral colonies were observed and there were various species of fishes present.

8.94 Site 1 was more diverse in marine life due to:

Ÿ higher species richness of hard corals (13 species); Ÿ additional invertebrate life associated with the hard coral cover e.g. gastropods; colonies of soft coral (Dendronephthya sp.) and the presence of sea pens in the sand; Ÿ presence of fishes, and Ÿ wider band of hard substrate suitable for further coral settlement and growth.

8.95 The percent cover of organisms in Site 1 and Site 2 were 2.26 % and 2.75 % respectively, much lower than that found at Pak Kok off north Lamma (13.09%) (Binnie, 1993). The coral communities inside the Sok Kwu Wan study area are therefore considered to be less established and have less conservation value than other coral communities around Lamma.

8.96 In the coral mapping survey, 280 coral colonies were recorded within the 33m x 50m surveyed area. The coral colonies were dominated by Platygyra sp., Plesiastrea sp.,Favites sp. and Favia sp.. All recorded coral colonies were of common genera in Hong Kong and their sizes were also small. Given these two factors, the conservation value of these coral colonies were not considered high. Detailed results of the coral mapping survey were presented in Appendix 8.5 of this chapter.

Evaluation of Subtidal Habitat within the Study Area

Criteria Discussion Naturalness Moderate. Disturbed by pollution loading from residential area, restaurants and Fish Culture Zone Size The entire Picnic Bay Diversity Low diversity Rarity Neither rare nor protected species recorded during the surveys Re-creatability This habitat can not be re-created Fragmentation N/A Ecological Linkage Not functionally linked to any highly valued habitat in close proximity Potential value Moderate Nursery/Breeding Ground No record of significant nursery or breeding ground during the surveys. But can provide nesting habitat for some disturbance tolerant bird species. Age N/A Abundance/Richness of The abundance and richness of wildlife recorded were low Wildlife Overall Ecological Value Low to moderate

Summary of Baseline Conditions

8.97 Terrestrial habitats found within the study area are in general young and disturbed. Two uncommon tree species were recorded in woodland habitat.

8.98 The shrubland/grassland mosaic habitats supported some rare and uncommon butterfly and bird species, both reported in field surveys and from literature review. Bird abundance in

MAUNSELL Page 8/28 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

the shrubland/grassland mosaic habitats, however, was low. Recorded species are typical of disturbed areas. Recently, in a small area of this habitat near the Pumping Station P2 site, calling of 6 male Romer’s Tree Frogs was reported during an ecological survey for a separated project within the study area of the present proposed Project (Halcrow China Limited 2002). This species is endemic to Hong Kong (Karsen et al. 1998).

8.99 The natural coastline along the south shore of Sok Kwu Wan varies between an estuarine environment to the west of Sok Kwu Wan and a granite boulder/cliff shoreline, semi- exposed coastlines to the east of Sok Kwu Wan. Intertidal surveys indicated that the rocky shore community consisted of organisms of exposed rocky shores and of boulder shores. The intertidal fauna recorded was of low abundance and diversity. The only aquatic species of conservation importance found so far is the horseshoe crab Tachypleus tridentatus in the sand flat. The only coastal bird species of conservation importance was the Reef Egret, as Black-eared Kite is habitat generalist.

8.100 Site1 (near Outfall Option 1): The boulder sublittoral zone extended approximately 20 m from the granite cliff-face. Hard corals were observed at depths of 3-4 m below chart datum. A total of 13 species were recorded and coral cover was less than 5%. All these corals are common and widely distributed in Hong Kong. Further out from the shoreline the seabed consisted of small boulders and at 30-40 m from the shoreline the substrate was mainly composed of fine sand/silt with isolated shell fragments.

8.101 Site 2 (Outfall Option 2): The narrow boulder sublittoral zone which extended out from the steep granite cliff face was approximately 5 m wide. Hard corals were not recorded growing below 1.5 m chart datum. Coral cover was estimated at less than 5%. In total 8 species of coral were recorded. All of them can be found at Site 1. Beyond the boulder zone the substrate changed rapidly to a silty/sand/mud seabed. The area of underwater bedrock and boulders, which provided substrate for coral colonisation, was smaller at site 2.

8.102 The coral community near Outfall Option 1 contains more hard coral species, while the conditions of the sea bottom near Outfall Option 2 are less suitable for coral colonisation.

8.103 In the coral mapping survey conducted in 2002, 280 colonies of corals were recorded within the 33m x 50m surveyed area. The genera of the corals were all common and widely distributed in Hong Kong. The majority of the coral colonies were also small in size.

Description of Assessment Methodologies

8.104 Impacts to habitats, species or groups were assessed based on the guidelines in Annexes 8 and 16 of the TM, the consultants’ local knowledge and international standards and practice in conservation biology.

8.105 The significance of ecological impacts is evaluated based primarily on the criteria set forth in Table 1, Annex 8 of the TM:

· habitat quality; · species affected; · size/abundance of habitats/organisms affected;

MAUNSELL Page 8/29 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

· duration of impacts; · reversibility of impacts; and · magnitude of environmental changes.

8.106 Impacts are generally ranked as "minor", "moderate" or "severe", although in a few cases a ranking of "minimal" (less than "minor") may be given. The ranking of a given impact would vary based on the criteria listed above. For example, an impact might be ranked as "minor" if it affected only common species and habitats, or if it affected only small numbers of individuals or small areas, whereas it might be ranked as "severe" if it affected rare species or habitats, large numbers of individuals or large areas. The major factors giving rise to a ranking are explained in the text. As noted in Annex 16 of the TM, a degree of professional judgement is involved in the evaluation of impacts.

Identification, Prediction and Evaluation of Environmental Impacts

8.107 This section of the report assesses potential impacts of the sewer alignment, outfall and STW from a cumulative ecological perspective.

Construction Stage

8.108 The proposed Project (Figure 2.5) includes construction of:

· sewer alignment; · pumping stations; · STW (sewage treatment works); and · submarine sewage outfall

Terrestrial Ecology

8.109 The sewer alignment and related facilities would follow much of the coastal belt of Sok Kwu Wan. It is envisaged that the sewer alignment would be built along the existing pathway that leads to Mo Tat Wan rather than along the natural shoreline. Under the Recommended Scheme, the STW would be built within the disused quarry rather than on a reclaimed site (preliminary scheme SMP option). This section of the report considers the potential impacts of project construction on terrestrial ecology. Potential sources of impact include:

· Habitat loss; · Site runoff; · Construction dust; and · Noise and disturbance.

Habitat Loss

8.110 The sewer alignment would lie underground in the urbanised area or the existing footpath until it reaches the STW. No natural habitats would be affected in this section of sewer during construction phase. The sewer pipe running from the STW to the submarine outfall

MAUNSELL Page 8/30 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

would be laid, also underground, along the existing footpath. The construction works for sewer pipe might encroach the habitat on the hillside, and temporary loss of shrubland- grassland habitat would be anticipated. The Recommended Scheme would cause a loss of 0.23 ha of shrubland/grassland habitat. Potential impacts on terrestrial vegetation, however, are predicted to be minor due to the disturbed nature of the habitats, the relatively short length of the sewer pipe and the commonness of the plant species recorded.

8.111 Due to the proximity of the two uncommon tree species to the road, construction of the pipeline may encroach to these trees. Potential impacts would be minor to moderate, and should be avoided or mitigated. The STW site would be located in a disused quarry which is sparsely vegetated. The pumping stations would sit on urbanised areas. Therefore, loss of shrubland-grassland habitats in the disused quarry due to the construction of these facilities is considered to be minimal to minor.

8.112 Impacts to birds for the sewer alignment, pumping stations and the STW site are predicted to be minor due to the disturbed nature of the habitats, the commonness of the species recorded and low bird abundance. In addition, most recorded species are disturbance tolerant.

8.113 Impacts to reptiles and terrestrial invertebrates are predicted to be minor due to the disturbed nature of the habitats and the commonness of the species recorded. For amphibians, one pumping station (Pumping Station P2, see Figure 2.5) would be located in the vicinity of the moist shrubland/grassland habitat in which Romer’s Tree Frog calling was reported. The pumping station site boundary is located further seaward than the moist area is, and has no overlap with the moist area. No habitat loss on the Romer’s Tree Frog habitat would be caused.

Site runoff

8.114 The alignment of the proposed Project basically runs along the shoreline of Sok Kwu Wan. The potential of terrestrial habitats affected by site runoff would be slim as they are located at higher elevations than the alignment is. The only concern in this aspect would be the Romer’s Tree Frog site close to the Pumping Station P2 location. Though there would be no direct loss of the Romer’s Tree Frog site from the present Project, if site runoff of large quantity from the present Project enters the site, it would deteriorate the quality of the habitat. In the case of the present Project, the scale of the pumping station construction work would be small, and the pumping station location is more seaward than the tree frog site. Moreover, the pumping station location and the Romer’s Tree Frog site was separated by a slope. There would be little chance for the site runoff, if any, to affect the Romer’s Tree Frog site. The impact is ranked as minimal. Nevertheless, in the light of the conservation value of this species, additional measures were proposed in Section 8.157 below to provide a complete protection of the habitat.

Construction Dust

8.115 Natural terrestrial habitats exist upland of the coastal path and backshore habitats exist towards the shore. Habitats adjacent to the path would be affected by construction works including trenching, soil disposal, machinery operation and general works areas. Providing

MAUNSELL Page 8/31 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

good site management practices are followed, dust should not settle offsite and is not predicted to reach natural habitats in measurable quantities. Any dust impacts would therefore be minimal.

MAUNSELL Page 8/32 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Noise and Disturbance

8.116 The works area would be linearly confined along an existing concrete pathway. No noisy construction procedure such as piling would be required. Due to the nature of the Project and scale of equipment used, impacts on fauna, including the six bird species of conservation importance, are predicted to be minimal.

Intertidal Ecology

8.117 This section of the report considers the potential impacts of project construction on intertidal ecology.

Potential sources of impact include:

· Habitat loss · Noise and disturbance; and · Site runoff.

Habitat loss

8.118 A section of sewer pipe connecting the outfall and the sewer pipeline along the footpath would occupy an area of intertidal habitat 10 m2 in size. The area occupied by the sewer would not be available for wildlife use. Due to the limited area of intertidal zone that would be occupied low abundance and diversity of intertidal fauna recorded in the area, and the availability of similar habitat in the vicinity, the impact would be thus expected to be minimal.

8.119 An area of 375m2 intertidal and shallow subtidal zone would be occupied by a temporary steel platform for Horizontal Directional Drilling during construction phase. The area, of which about two third (about 250m2) within intertidal zone, in which both the fauna abundance and diversity recorded were low, would be disturbed only by the supporting piles of the platform. Due to the level of disturbance is not severe and the availability of similar habitat in the vicinity, the impact would be thus ranked as minor.

Noise and disturbance

8.120 A section of sewer pipe connecting the outfall and the sewer pipeline along the footpath would occupy an area of intertidal habitat 10 m2 in size. Reef Egret is the major disturbance- sensitive receiver in the intertidal zone, while Black-eared Kite would not be subject to disturbance due to their flying height. Bird abundance on the rocky shores, however, was low and most species are common and widespread, and not dependent on rocky shores. Although the application of a rising pipeline would significantly reduce the degree of disturbance caused, the area occupied by the sewer remains the major consideration on the assessment of impacts. Due to the limited area of intertidal zone that would be occupied in any event, however, the impact would be expected to be minimal.

Site runoff

MAUNSELL Page 8/33 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8.121 Construction of the sewer pipes would cause considerably small volume of site runoff, taking into account the limited extent of trench excavation. The impact to the natural coastline due to site runoff from construction is considered minor. Juvenile horseshoe crabs were recorded on the intertidal sand flat. Despite the close distance to the sandflat, construction of the pumping stations and the section of sewer alignment between them would take place on already urbanised area only. Considering the scale of the construction work and providing good site management practices being followed, no impact on the horseshoe crabs from site runoff would be expected. Provision of the sewer system would produce positive impacts on intertidal ecology on the sand flat by reducing the wastewater input to the sand flat.

Subtidal Ecology

8.122 This section of the report considers the potential impacts of project construction on subtidal ecology.

8.123 Potential sources of impact include: · Habitat loss from dredging; · Suspended solid from dredging; · Drilling fluid; · Site runoff; · Construction dust; and · Noise and disturbance.

Habitat loss from dredging

8.124 Technique of Horizontal Directional Drilling (HDD) would be used for the section of sewer between the intertidal zone and 480m away from the coastline. Application of this technique avoids the disturbance on coral habitats caused by traditional dredging The only potential impact on corals would be a temporary steel working platform of size 15m wide by 25m long, which would be erected close to the tide line. The platform would cause a temporary loss of 375 m2 intertidal and shallow subtidal area. According to Figure A8.5-1 in Appendix 8.5 of this chapter, the distribution extent of coral colonies would not be encroached by the platform. Its seaward limit would lie before the landward boundary of Zone 1 in Figure A8.5-1. A barge would be used during the HDD works. As confirmed by the engineer, the barge would only be operated around 400-500m away from the coast where the HDD pipe is about to break the seabed. No impact on coral colonies from the HDD works is anticipated.

8.125 A temporary seabed loss due to the dredging at the remaining 240m pipeline and diffuser site would be caused. The majority of the temporary seabed loss area is of muddy substrate, with no special ecological value. The impact of the temporary loss of soft seabed caused by dredging is thus ranked as minor. Permanent seabed loss would not result after the construction works are completed as the pipeline and diffuser would be located below the seabed.

Suspended solid from dredging

8.126 Suspended solids created in dredging would increase the turbidity of the waters, which could

MAUNSELL Page 8/34 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

bury sessile organisms, and thus reduce the amount of light reaching the sea bed. Furthermore, those suspended solids might settle on the surface of corals, further reduce the amount of light available to corals and also disturb the active feeding activities of corals. Resuspension of sediments would also reduce oxygen levels and potentially release pollutants into the water column. All these consequences may affect the health and survival of corals. These impacts, short-term and localised in nature, however, would not be expected being significant to the subtidal ecology of Sok Kwu Wan, especially hard corals, due to the long distance of the dredging area from the coastline (480m) and the application of double – layered silt curtain around the dredging site and a dredging rate of not greater than 55 m3/hr. Water quality assessment also showed that the suspended solid level would match the Water Quality Objectives inside the nearest Fish Culture Zone (224 m away from the alignment) during the construction phase. The hard coral colonies recorded in the dive survey of 2002 were located further away from the dredging site than the FCZ was. Impacts of suspended solid increase on corals is thus not anticipated. Other marine fauna in the vicinity include three Pteroeides sp. (sea pens) observed in Site 1 (Outfall Option 1) during 1998 dive survey. Though they were located more seawards than the coral colonies were, and thus closer to the dredging site, this animal inhabits soft substrate habitat and can tolerate change in suspended solid level.

Release of contaminants from dredging

8.127 During dredging, contaminants such as heavy metals and other toxic substances would be released from sediment when seabed was disturbed. The potential for adverse effects on water quality through mobilization and release of contaminants into the surrounding water column during dredging would depend on the level of contamination of the marine sediment. As part of the Project, a sediment sampling and testing survey within the Study Area was undertaken to provide an indication of the sediment quality for the purpose of this EIA Study.

8.128 Since the sediment testing results showed that marine sediments to be dredged for the proposed submarine outfall were classified as Category L and no exceedance of the respective LCELs were recorded (Section 6 refers), the potential impact of contaminants released from the sediments would be of minimal. The predicted nutrient levels including unionised ammonia would be well below the WQO during the dredging activities (see Section 5). In other words, the potential release of metals, organics and nutrients from sediment into the water column would not result in adverse impacts on water quality during the dredging works.

Drilling fluid

8.129 The drilling process of the HDD technique would require drilling fluid, which would be a mixture of water and specialized additives. According to the information provided by the Contractor, the drilling fluid (Bentonite fluid) that would be used for the drilling process is environmentally friendly and without dangerous contaminants, and is extensively used in Europe as well as America for both HDD and water well applications. The used drilling fluid (slurry) would be circulated back to the ground surface and collected in return pits for recycling or disposal. Discharge of the slurry to the bay would only occur when the drill breaks the ground at around 480m from the coast. However, the discharge of slurry would

MAUNSELL Page 8/35 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

occur in the short term. With the deployment of silt curtains around the exit area as stated in Appendix 2.1, adverse water quality impact associated with the discharge of the slurry during breaking the ground would not be anticipated. No ecological impact is anticipated.

Site Runoff

8.130 Construction site runoff can contain sediments, organic substances, oil, grease and solvents that can affect marine ecology. These substances can increase turbidity, decrease oxygen levels and introduce contaminants, potentially injuring or killing benthic organisms and driving mobile organisms away from the vicinity and thereby causing a short-term loss of habitat or degradation of habitat quality.

8.131 Impacts would be short-term and would be largely self–corrected after project completion without active restoration efforts. Sensitive species near the site that could be directly affected by runoff would include juvenile life stages of various marine organisms. The impacts of such runoff would be ranked as minimal as the sewer pipe would be laid along the existing footpath and does not require construction directly along the coastline.

Construction Dust

8.132 Dust from the construction areas could settle over nearby waters, increasing turbidity and possibly introducing contaminants into the marine environment. Providing good site management practices are followed, dust should not settle offsite and is not predicted to reach natural habitats in measurable quantities. Impacts would not be predicted to have direct impacts upon species of high conservation importance. Any dust impacts would therefore be negligible and ranked as minimal.

Noise and Disturbance

8.133 Noise and disturbance from underwater and coastal construction including dredging activities could cause disturbance-sensitive marine fauna to migrate from the area, or cause secondary effects such as reduced feeding efficiency. However, mobile fauna which are sensitive to disturbance would most likely have vacated the area earlier during the course of the dredging. Impacts would therefore be ranked as minor.

Summary of Construction Impacts

8.134 The area is considered to be of some conservation interest due to:

· The location of potential country parks; and · the existence of corals in the vicinity of the study areas;

8.135 Construction of the sewage treatment project in Sok Kwu Wan at Lamma would cause little disturbance to terrestrial and intertidal environments but would cause larger impacts on the subtidal environment. 8.136 Impacts on intertidal habitats would not occur on the sand flat and would occur in only a limited area on the rocky shore. Construction of a subtidal outfall would involve a temporary seabed loss of 10,400 m2. Since the seabed loss area is away from shallow

MAUNSELL Page 8/36 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

subtidal zone and of muddy substrate, no hard corals would be directly impacted by the dredging work, and the seabed which is available for hard coral colonization would not be affected. Given the distance and the application of silt curtain, indirect impacts from suspended solids during dredging would not be expected.

8.137 The sewer alignment mostly lies underground along the existing footpath and the pumping stations are located in urbanised areas. Ecological disturbance is therefore expected to be minimal. In addition, the disturbance to the natural coastline would be limited to the outfall location and is also expected to be minimal.

8.138 The Alternative STW site is located on a disused quarry which is sparsely vegetated.

8.139 Potential ecological impacts of project construction are summarised in the following table. The overall impacts of project construction on ecology are predicted to be minor.

Table 8.15 Construction-stage Impacts

Potential Location Source of impact Receiver Severity Mitigation Impacts Required Habitat loss Terrestrial Construction Encroachment Shrubland- Minor No of sewer from grassland pipeline construction habitat on works hillside Damage of Rare and Minor to Fencing of the tree roots or restricted tree moderate trees. (detailed trunks species in below sections) Construction Encroachment Shrubland- Minimal to No of STW from grassland minor construction habitat in works disused quarry Construction Loss of Avifauna Minor No of sewer feeding Non avifauna Minor No pipeline and ground STW Intertidal Construction Loss of Intertidal Minimal No of sewer intertidal fauna pipeline habitats Platform for Supporting Corals No impact No HDD piles of the Other marine Minor No platform organisms Subtidal Construction HDD Corals No impact No of submarine technique outfall pipeline Dredging for Loss of soft - Benthic Minor No diffuser bottom seabed organisms Construction Terrestrial Adjacent dust Inhibition of vegetation growth terrestrial Minimal No and pollution of waterbodies habitats Subtidal Increase of turbidity of nearby Adjacent Minimal No coastal waters marine habitats

MAUNSELL Page 8/37 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Potential Location Source of impact Receiver Severity Mitigation Impacts Required Noise and Terrestrial, Disturbance- Disturbance intertidal and Changes in distribution, activity sensitive Minimal No subtidal patterns or breeding success wildlife species on and near the site Site runoff Terrestrial Deterioration of habitat quality Romer’s Tree Minimal* Good site Frog site practices Intertidal Decrease water quality; bury Intertidal Minor (detailed in and suffocate sessile organisms habitats below Sandflat No impact sections) Subtidal Decrease water quality; bury Adjacent Minimal (*Barriers in and suffocate sessile organisms; marine Pumping drive away mobile organisms habitats and Station P2 dependent site. species Additional measures for Romer’s Tree Frog site though the impact is minimal.) Suspended Subtidal Decrease water quality; bury corals No impact Silt curtains solid and suffocate sessile organisms; and closed drive away mobile organisms grab dredging are proposed in Section 5 of this report. Contaminants Subtidal Effects on water quality Marine No impact Silt curtains organisms and closed grab dredging are proposed in Section 5 of this report. Drilling fluid Subtidal Effects on water quality Marine No impact Silt curtains is organisms proposed in Section 5 of this report.

Operation Stage

Terrestrial Ecology

8.140 Potential sources of impact of project operation on terrestrial ecology include:

· Noise and disturbance

8.141 Operation of the sewer and STW facilities is not expected to generate significant levels of noise. Impacts on disturbance-sensitive wildlife (e.g., Reef Egret, Crested Goshawk) are unlikely to be detectable and at most would be minimal.

Intertidal Ecology

MAUNSELL Page 8/38 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8.142 No impact on intertidal habitats would be expected from the operation of the sewer system.

MAUNSELL Page 8/39 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Subtidal Ecology

8.143 This section of the report considers the potential impacts of project operation on marine ecology. Potential sources of impact include:

· Maintenance of outfall · Marine water quality · Emergency discharge

8.144 Maintenance dredging for submarine outfalls is not required as it might cause damage to the underlying pipeline. Instead, the diffusers of the outfalls might need to undergo cleaning operations in the case of blockage. This operation, however, would not involve dredging. So the impacts form repair and maintenance would be expected being minimal to the subtidal ecology of Sok Kwu Wan.

8.145 Installation of a sewerage system and a STW system would vastly improve the level of treatment currently available in this area. The current direct discharge of untreated waste water into inner Sok Kwu Wan would be replaced by an outward and deep water discharge of treated sewage. This would be considered as a positive impact which may outweigh the potential negative impacts of the Project on marine ecology.

Marine water quality

8.146 Exceedances of WQO limit for TIN are predicted during the normal operation of the sewerage system. The only discharge parameter that would exceed WQO limits, despite minor, is Total Inorganic Nitrogen (TIN). However, the exceedances are attributable to the high background TIN levels. The predicted TIN levels, however, were considered to be over-estimated as they were calculated by adding the elevated TIN levels directly to the measured background TIN levels. The prediction was not taken account of the beneficial effect of eliminating untreated or partially treated sewage discharges to the Picnic Bay upon the operation of the proposed Project (see Section 5.63). The proposed system would collect and transfer sewage from the Sok Kwu Wan area to the proposed STW for treatment and would discharge treated sewage at a long submarine outfall of around 750 m from the coast. Having considered the high background TIN level, the treatment process of the STW would include denitrification in order to reduce the potential water quality impact in relation to TIN. With the denitrification applied, more than 50% reduction in TIN level would be achieved after treatment. In addition, the system would discharge the treated effluent through the submarine outfall at a location 750m from the coastline in where dilution and dispersion effect would be more efficient and fast, instead of discharges of untreated or partially treated sewage along the coastline of Sok Kwu Wan, accumulates in the inner Picnic Bay, and slowly disperses toward the open sea, as the existing situation. As such, the potential water quality impact in relation to TIN levels on the marine organisms, would not be expected to be worse than the existing conditions.

8.147 Compared with the current situation that TIN source discharges on the coastline, the situation after the proposed Project implemented would not be expected to cause significant adverse effect on marine organisms, including corals, in shallow subtidal zone. The impact

MAUNSELL Page 8/40 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

is thus ranked as minimal.

Emergency discharge

8.148 The emergency discharge from the pumping stations and STW may be the consequence of pump failure or interruption of the electrical power supply. Water quality impact arising from the emergency discharge of the pumping stations and STW are anticipated.

8.149 As detailed in the Section 5 of this report, sufficient preventive measures would be provided. Standby pumps, standby generators, temporary storage space for sewage, and action plan would be prepared. The provision of those measures would prevent the failure of the system and the resulted sewage overflow and emergency discharge. Though the chance is remote, in an extreme case that all the measures fail, contingency plan would be implemented to minimize the water quality impact at the inner part of Picnic Bay and the shallow subtidal zone.

8.150 With the implementation of the above-mentioned mitigation measures and contingencies, the possibility of an emergency overflow occurring and the potential water quality impacts would be minimised. The key aspects of the recommendations are summarised as follows:

· Standby pump at all pumping stations and the STW in case of pump failure; · Standby generator at all pumping stations in case of interruption of electrical power supply; · 24-hour temporary storage for all pumping stations in emergency; · Use of SBR units as storage tanks in case STW failure; · No emergency discharge is allowed at Pumping Station P2 and the STW; · Automatically shutdown the pumping station at Lo So Shing in case of Pumping Station P1a failure; · Automatically shutdown the upstream pumping stations in case of Pumping Station P1b failure; · Automatically shutdown the upstream pumping stations in case of Pumping Station P2 failure; · Automatically shutdown all pumping stations in case of STW failure; · Implement a telemetry system to ensure prompt action to be undertaken in an emergency occasion.

8.151 It should be noted that the occurrence of emergency discharge would be episodic and very short-termed. Compared with the long-termed improvement of water quality inside Picnic Bay from the proposed Project, and given the above-mentioned measures to prevent and minimize the emergency discharge, the impact is ranked as minimal.

Summary of Operational Impacts

8.152 The potential ecological impacts of project operation are summarised in the following table.

MAUNSELL Page 8/41 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Table 8.16 Operation-stage Impacts

Potential Location Source of Receiver Severity Mitigation Impacts impact Required Noise and Terrestrial Noise and Changes in Disturbance- Minimal No disturbance disturbance distribution, sensitive activity wildlife patterns or species on and breeding near the site success Subtidal Maintenance Disturbance Adjacent Minimal No marine habitats and dependant species Marine water Subtidal STW Marked Sok Kwu Wan Positive N/A quality operation improvement bay ecology effects in water quality Marine water TIN level Adjacent Minimal No quality would exceed marine WQO, but habitats and within the dependant range of species current background variation. Emergency Episodic Adjacent Minimal Provided in discharge marine water marine Section 5 of quality impact habitats and this report. dependant species

Cumulative Impacts

8.153 Three recognised sites of marine conservation interest are located near the study area, i.e. the waters to the west of Ha Mei Wan and of the northern part of Tung O Bay; the coastal waters of south Lamma; Sham Wan and (Figure 8.1). The waters to the west of Ha Mei Wan and of the northern part of Tung O Bay were identified in the Territorial Development Strategy Review as a ‘Significant Area’ for Marine Conservation (PELB 1998). Identified as a ‘Unique Area’ for Marine Conservation (PELB 1998), the coastal waters of south Lamma are also a proposed Marine Park. The proposed South Lamma Marine Park would cover the waters south of Lo So Shing Beach, along the coastline of south Lamma, including Sham Wan, to the north boundary of Shek Pai Wan. An area of 4 hectares including the sandy beach and the adjacent shallow shore in Sham Wan was designated as an SSSI on 3 June 1999. This area has also been identified as important for Green Turtle Chelonia mydas nesting (Morton 1998) and gazetted as a Restricted Area under the Wild Animals Protection Ordinance (Cap. 170) for green turtles in 1999.

8.154 These three areas, however, are all sheltered from Sok Kwu Wan by the landmass of Lamma Island. As the water quality modelling results has indicated that most parameters would be within the WQO standard. Only TIN would marginally exceed the WQO and the

MAUNSELL Page 8/42 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

exceedances could be attributed to the high background level. The change of water quality during the operation phase of the present Project would be acceptable for water quality sensitive receivers inside Picnic Bay. Outside the bay, the currents in Lamma channel would further facilitate the dilution process. The change in water quality would thus be undetectable. No adverse impacts on all these recognised sites of marine conservation interest would be anticipated.

8.155 The construction of the STW, sewer alignment, and outfall must be considered in the context of its surroundings. The current main contributors to impacts to marine ecology within Sok Kwu Wan are the Far East Cement operations and the mariculture trade. Therefore, cumulative impact arising from Projects concurrent with the construction activities for the present Project is expected to be minimal. In addition, the impact to the marine ecology has been reduced by selection of the Alternative STW site, which is located in a disused quarry to the southeast of the RTS. Operation of the STW would further improve water quality in Sok Kwu Wan, helping to offset negative effects of mariculture operations.

Mitigation of Adverse Environmental Impacts

8.156 The TM (Annex 16) and the TC require that mitigation of ecological impacts be sought in the following order of priority: (1) avoid, (2) minimise, (3) compensate on-site and (4) compensate off-site. At each stage, residual impacts should be re-assessed to determine whether there is a need to proceed to the next stage of mitigation. The following measures are proposed to mitigate the impacts discussed in the preceding sections.

Construction Stage

Terrestrial Ecology

8.157 The two uncommon tree species would be labelled and probably fenced to avoid direct or indirect disturbance during construction. Works areas should avoid woodland habitats, in particular where these trees are located. Construction and maintenance of site runoff control measures would be required at all work sites during construction. These should include barriers to direct runoff to sand/silt removal facilities (sand/silt/traps and/or sediment basins); minimisation of earthworks during rainy season (May to September); and coverage of sand/fill piles and exposed earth during storms. Special attention should be paid during the breeding season of Romer’s Tree Frog (March to September) to ensure their habitat landward to Pumping Station P2 site is well protected from site runoff. Barriers should be deployed completely along the landward side of the pumping station site boundary to prevent any site runoff from entering the tree frog habitat. Intactness of the barriers should be frequently inspected.

Intertidal Ecology

MAUNSELL Page 8/43 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

8.158 Construction and maintenance of site runoff control measures would be required at all work sites during construction. These should include barriers to direct runoff to sand/silt removal facilities (sand/silt/traps and/or sediment basins); minimisation of earthworks during rainy season (May to September); and coverage of sand/fill piles and exposed earth during storms.

MAUNSELL Page 8/44 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Subtidal Ecology

8.159 Due to the application of HDD technique, no coral colonies would be directly affected by the construction works. Mitigation measures for direct impacts on coral colonies such as Translocation Plan is thus not considered necessary. As the drilling would be conducted 10m below seabed level and the majority of coral colonies are colonised on boulders, indirect impacts from vibration during the drilling would not be anticipated. Information provided by the Engineer showed that over 80 samples of this method were found during 1998 - 2001 at different locations of the world in a variety of substrate types (from soft soil to hard rock). No adverse effects were found in all these cases. Based upon these previous examples and the details of the technique as described above, HDD technique would be safe for marine organisms. No need for an ecological monitoring programme is anticipated.

8.160 To reduce impacts of sediment resuspension upon nearby habitats and organisms during dredging, all dredging should be done using a closed-grab dredger, and silt curtains should be deployed around the dredger during all dredging activity.

8.161 Construction and maintenance of site runoff control measures would be required at all work sites during construction. These should include barriers to direct runoff to sand/silt removal facilities (sand/silt/traps and/or sediment basins); use of silt curtains along coastline; minimisation of earthworks during rainy season (May to September); and coverage of sand/fill piles and exposed earth during storms.

8.162 Contaminants from dredging and drilling fluid are considered as having no ecological impact. Silt curtains, however, could further prevent their release into the water bodies.

Summary of Construction-stage Mitigation Measures

8.163 The mitigation measures proposed above are summarised in the following table.

Table 8.17 Proposed Construction-stage Mitigation Measures

Source of Impact Proposed Mitigation Predicted Degree of Residual Impact Habitat loss · Labeling and fencing of the uncommon tree species Acceptable · Avoidance of use of woodland habitats as Works Area, in particular where these trees are located Site runoff · Construction and maintenance of sand/silt removal Acceptable facilities · Timing of earthworks · Coverage of sand/fill piles during storms · Barriers should be deployed completely along the landward side of Pumping Station P2 site boundary. Intactness of the barriers should be frequently inspected. Special attention should be paid during March to September. Suspended solid · Use of closed-grab dredging Acceptable Deploy silt curtains during dredging Contaminants & · Silt curtains Acceptable Drilling fluid

MAUNSELL Page 8/45 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Operation Stage

8.164 No dredging would be involved for maintenance of outfall, and the TIN exceedence would be within the range of current background variation, no mitigation measures in operation stage are required. Measures to address emergency discharge are provided in Section 5 of this report.

Definition and Evaluation of Residual Environmental Impacts

8.165 With the implementation of the mitigation measures recommended, residual ecological impacts may include net loss of grassland habitat and intertidal habitat, are not expected to be significant.

Ecological Monitoring and Audit

8.166 Due to the limited scale of the Project, the low ecological value of the fauna and flora recorded, the minor degree of impacts caused, and also the previous records of HDD technique as mentioned in Section 8.160 above, no need for an ecological monitoring programme is anticipated. No ecological monitoring and audit is proposed.

MAUNSELL Page 8/46 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

References Cited

Ades, G.W.J. 1999. The species composition, distribution and population size of Hong Kong bats. Memoirs of the Hong Kong Natural History Society 22: 183-209. Anon. 1995. Wildlife Windows Two. Porcupine! Number 12. Newsletter of the Department of Ecology and Biodiversity, Hong Kong University. Anon. 1996. Wildlife Windows. Three. p. 23. Porcupine! Number 15. Newsletter of the Department of Ecology and Biodiversity, Hong Kong University. Anon. 1997. Wildlife Windows. Two. p. 25. Porcupine! Number 16. Newsletter of the Department of Ecology and Biodiversity, Hong Kong University. Anon. 1998. Wildlife Windows. Two. p. 24. Porcupine! Number 17. Newsletter of the Department of Ecology and Biodiversity, Hong Kong University. Ashworth, J.M., R.T. Corlett, D. Dudgeon, D.S. Melville, and W.S.M. Tang. 1993. Hong Kong Flora and Fauna: Computing Conservation. World Wide Fund for Nature Hong Kong. November 1993. Binnie Consultants Ltd. 1995. Marine Ecology of Hong Kong: Report on Underwater Dive Surveys (October 1991 - November 1994). Report submitted to Civil Engineering Department, Hong Kong Government. Carey, G. 1993. Hong Kong Bird Report 1992. Hong Kong Bird Watching Society, Hong Kong. Carey, G. 1994. Hong Kong Bird Report 1993. Hong Kong Bird Watching Society, Hong Kong. Carey, G. 1995. Hong Kong Bird Report 1994. Hong Kong Bird Watching Society, Hong Kong. Carey, G. 1996. Hong Kong Bird Report 1995. Hong Kong Bird Watching Society, Hong Kong. Carey, G. 1998. Hong Kong Bird Report 1996. Hong Kong Bird Watching Society, Hong Kong. Carey, G. J., Chalmers, M. L., Diskin, D. A., Kennerley, P. R., Leader, P. J., Leven, M. R., Lewthwaite, R. W., Melville, D. S., Turnbull, M. and Young, L. 2001. The Avifauna of Hong Kong. Hong Kong Bird Watching Society, Hong Kong. Chiu, H.M.C. and B. Morton. 1999. The distribution of horseshoe crabs (Tachypleus tridentatus and Carcinoscorpius rotundicauda) in Hong Kong. Asian Marine Biology. vol. 16(1999), pp. 185-196. Corlett, R. T. 2001. Is Javan Mongoose native and does it matter? Porcupine! 24: 19. Halcrow China Limited. 2002. 10 Year Extended LPM Project Phase 2, Package G – Outlying Islands Features IN Sok Kwu Wan, Lamma Island Project Profile. Karsen, S. J., Lau, M. W. N. and Bogadek, A. 1998. Hong Kong Amphibians and Reptiles. Second edition. Urban Council, Hong Kong.

MAUNSELL Page 8/47 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc CE 20/96: Outlying Island Sewerage Scheme Stage 1 Phase II Package J – Sok Kwu Wan Sewage Collection, Treatment Drainage Services Department and Disposal Facilities - EIA Report

Lau, M. W. N. and Dudgeon, D. 1999. Composition and distribution of Hong Kong Amphibian fauna. Memoirs of the Hong Kong Natural History Society 22: 1-80. Leven, M. R. 2000. Shrubland Birds in Hong Kong: Community Structure, Seasonality and Diet. Unpubl. PhD thesis, University of Hong Kong. Maunsell 1997. Outlying Islands Sewerage – Stage I Phase I. Report submitted to Drainage Services Department. McGilvray, F. and Geermans, S. 1997. The status of the Green Turtle in Hong Kong and an action plan for its survival. The Hong Kong Marine conservation Society. Morton, B. 1998. Hong Kong’s Marine Parks Ordinance and designation of the first marine parks and reserves: where next? In The Marine Biology of the South China Sea III. Proceedings of the Third International Conference on the Marine Biology of the South China Sea, Hong Kong, 28 October- 1 November 1996. (ed. Brian Morton) p.541-562. Hong Kong University Press, Hong Kong. Morton, B. and Morton, J. 1983. The Sea Shore Ecology of Hong Kong. Hong Kong University Press, Hong Kong. Planning Department 1993. Terrestrial Development Strategy Review: Environmental BaselineConditions. Planning Department 1995. The Final Technical Report on Territorial Development Strategy Review, 1995: A New Development Framework for Hong Kong – A Response to Change and Challenges – Part Two : The Study Process and Inputs for Strategy Formulation. Planning, Environment and Lands Bureau 1998. Terrestrial Development Strategy Review: A Response to Change and Challenges. Final Executive Report. Viney, C., Phillipps, K. & Lam, C. Y. 1996. Birds of Hong Kong and South China. Government Printer, Hong Kong. Walthew, G. 1997. The status and flight periods of Hong Kong butterflies. Porcupine! No. 16: 34-37. Wilson D. E. and Reeder, D. M. 1992. Mammal species of the world: A taxonomic and geographic reference. Smithsonian Institution Press, Washington & London. Wilson, K.D.P. 1995. Hong Kong Dragonflies. Urban Council of Hong Kong, Hong Kong. Wilson, K. D. P. 1997. An annotated checklist of the Hong Kong dragonflies with recommendations for their conservation. Memoirs of the Hong Kong Natural History Society 21: 1-68. Xing, F. W., S.C. Ng, and L.K.C. Chau 2000. Gymnosperms and angiosperms of Hong Kong. Memoirs of the Hong Kong Natural History Society. 23: 21-136. Zhao, E. M. 1998. China Red Data Book of Endangered Animals: Amphibia & Reptiia. Science Press, Beijing. Zheng, G. M. and Wang, Q. S. 1998. China Red Data Book of Endangered Animals: Aves. Science Press, Beijing.

MAUNSELL Page 8/48 P:\A71097\REPORTS\Final EIA\Nov02\Sec_8-rev.doc