Wednesday 27 November 2013

Septic tanks and soakaway pits (STS) systems will not work in country park enclaves

The Town Planning Board has recently sought comments on three Draft Outline Zoning Plans for areas in “country park enclaves”, namely:

1. Hoi Ha - Draft Hoi Ha Outline Zoning Plan No. S/NE-HH/1;
2. Pak Lap - Draft Pak Lap Outline Zoning Plan No. S/SK-PL/1;
3. So Lo Pun - Draft So Lo Pun Outline Zoning Plan No. S/NE-SLP/1.

In terms of dealing with sewage issues, there is no existing public sewer or planned sewerage project in any of these enclaves and at present, each house is typically served with its own on-site septic tanks and soakaway (STS) system. Any increase in residential developments would require additional facilities, including each property having their own individual STS system and these would need to comply with relevant standards and regulations, such as EPD’s Practice Note for Professional Person (ProPECC) 5/93. According to the relevant EPD standards and regulations (Guidance Notes on Discharges from Village Houses1), this means:

1. Dispersing untreated wastewater into the surrounding soil and relying on the soil to remove polluting material from the wastewater;

2. Polluting material being removed from the wastewater only after it has travelled a long distance in the soil; and

3. An STS system is not feasible in areas with a high ground water table.

This is accepted policy. According to the Minutes of 1032nd  Meeting of the Town Planning Board held on 26.4.20133, at Para 82, the Chairman of the Town Planning Board stated:

“ … on sewerage concern, the use of septic tanks for sewage treatment purpose in Small House developments was common and acceptable”2

Unfortunately, this statement and the Government’s whole approach to STS systems in these enclaves is wrong, for the following reasons:  

Issue 1 – The underlying geology in these enclaves will not support the use of STS systems

The use of STS systems for sewage treatment purpose in Small House developments, as proposed in the Draft Outline Zoning Plans is not acceptable, because the Town Planning Board have not been briefed about the Geological Constraints of allowing the use of on-site septic tanks and soakaway (STS) systems in these enclaves.

The surface sediment is porous and highly permeable

The first problem is the superficial surface sediment in each of these enclaves comprises porous and permeable sedimentary deposits, as follows:

1. The surface sediment in Hoi Ha is a mixture of alluvium, beach deposits and debris flow deposits.

2. The surface sediment in Pak Lap is a mixture of alluvium and beach deposits.

3. The surface sediment in So Lo Pun is a mixture of terraced alluvium, debris flow deposits and estuarine and intertidal deposits.

All of these deposits are porous and permeable and allow for rapid drainage, so no matter how far the distance, adequate purification cannot be achieved and because each of these enclaves is at the mouth of a watercourse, this means all of the pollutants in the wastewater will ultimately be deposited untreated into the sea.

See the Geological Survey maps below: 

Hong Kong Geological Survey map (Sheet 8 – Sai Kung) - Geology at Hoi Ha3


Key:  Alluvium (Qa), Beach Deposits (Qb) and Debris Flow Deposits (Qd)

Hong Kong Geological Survey map (Sheet 12- Clearwater Bay) - Geology at Pak Lap4


Key:  Alluvium (Qa) and Beach Deposits (Qb)

Hong Kong Geological Survey map (Sheet 3 – Sheung Shui) - Geology at So Lo Pun5


Key:  Alluvium (Qpa), Debris Flow Deposits (Qpd) and Estuarine and Intertidal Deposits (Qi)


Issue 2 – The underlying geology means these enclaves are susceptible to alluvial flooding

The second problem is that because of these deposits are permeable and lie on top of impermeable deposits and because each of these enclaves is on a watercourse, it is susceptible to alluvial flooding. Alluvial (or permeable superficial deposits) flooding occurs where rivers or streams are hydraulically connected to alluvial material because the river valley comprises permeable deposits overlying impermeable rocks. See an illustration of how this occurs in the diagram below:

Diagram illustrating how alluvial flooding occurs6


Evidence of Alluvial Flooding in the three enclaves

One of the most obvious signs of this in such areas is the presence of surface flooding and illustrations provided in each of the Draft Outline Zoning Plans shows evidence to suggest that alluvial flooding is taking place in each of these enclaves. See the pictures below:

Figure 5c in TPB Paper 9368 - Draft Hoi Ha Outline Zoning Plan
The water logging in Photo 4, suggesting the presence of a high water table as a result of Alluvial Flooding



Plan 12 in TPB Paper 9420 – Draft Pak Lap Outline Zoning Plan
The presence of “water ferns”, suggesting the presence of a high water table as a result of Alluvial Flooding


Figure 5c in TPB Paper 9331 - Draft So Lo Pun Outline Zoning Plan
 Freshwater Marshes at the Central Part of So Lo Pun. The water logging in Photo 10, suggesting the presence of a high water table as a result of Alluvial Flooding


In such systems, the groundwater in the alluvial deposits and the stream are hydraulically connected, which means they are not separate, but are part of the same interconnected system. The implications of this on allowing the use of STS systems in each of these enclaves are considerable:

1. Polluting material will not be removed from the wastewater, but will flow untreated directly through the underlying sedimentary deposits into the stream;

2. On-site septic tanks and soakaway (STS) systems will not function because of the high ground water table in each of these enclaves; and

3. Buffer zones will not work because of the hydraulic connectivity between the groundwater in the alluvial deposits and the streams.

The implications for human health and the likely impact on the environment are of even more concern

Issue 3 - Threat to human health

Outbreaks of groundwater borne pathogens linked to STS systems in the USA7

According to investigations conducted in the Northwest United States, outbreaks of groundwater borne viral pathogens linked to Septic Tank Systems have been documented in several locations, with the following significant findings:

1. More than 400 people were infected with gastroenteritis related to contaminated groundwater in 1995;

2. A number of major outbreaks of gastroenteritis have been attributed Norwalk-like virus in numerous states; and

3. Improperly constructed drainfields, high water tables or inappropriate geological settings can allow pathogenic bacteria and viruses to reach groundwater, where they can survive for days and travel up to 30 metres.

These findings are significant, because they relate to “viral outbreaks”. SARS and Bird Flu are both viral infections and Hong Kong has had outbreaks of both of these diseases in recent years - H5N1 in 1997 and SARS in 2003. Moreover, the threat of a virus with future global pandemic potential reaching, then spreading from Hong Kong has not subsided.

Specific health concerns in Hong Kong

In an article in the South China Morning Post on 15 August 201318 on an H7N9 bird flu outbreak in China, the results of a study show: “The H7N9 bird flu that emerged on the mainland in March may be spreading through human faeces”. In respect of these findings, Hong Kong microbiologist Yuen Kwok-yung is quoted as saying: "This has important implications on the infection control strategies for H7N9 virus infection, as the influenza virus in stools may contaminate the surrounding environment".8

It should be noted, Hong Kong’s contingency plan for pandemics is mainly geared towards standard control measures like personal and environmental hygiene, social distancing and hospital infection control.

Issue 4 - Threats to species and habitats of conservation and ecological significance

Releasing untreated wastewater into the environment will have devastating consequences9

It is widely recognized that conventional septic systems are not adequate for removing nitrate, and only partly remove phosphorus, certain pathogens, and certain other compounds, especially where soils or ground water conditions are marginally suitable. Anything that is not removed by the soil will end up in groundwater. It is important to note the two main nutrient products of STS systems are nitrogen and phosphorous.

Nutrient enrichment of surface waters by nitrogen and phosphorus is one of the leading causes of pollution of lakes, rivers, and coastal bays in the United States. Nutrient enrichment can cause a host of negative ecological effects on streams and lakes, including loss of water clarity, proliferation of aquatic weeds, algae blooms, and drop-offs in dissolved oxygen, a critical factor for fish and other aquatic life.

In terms of the three enclaves, Hoi Ha Wan is home to coral communities and So Lo Pun is home to an Ecologically Important Stream (EIS) and marshland habitats, both of which will be highly susceptible to any increases in nitrogen and phosphorous levels in the groundwater, which because of the local geology will not be filtered by STS systems as planned.

Suspended and bedded sediments (SABS)

In addition to nutrients, Septic Tanks also produce Suspended and Bedded Sediments (SABS). SABS are defined by the US Environmental Protection Agency (EPA) as particulate organic and inorganic matter that suspend in or are carried by the water, and/or accumulate in a loose, unconsolidated form on the bottom of natural water bodies10.

According to the Civil Engineering and Development Department (CEDD) in Hong Kong:
“… human activities such as sewage discharge generate suspended sediments”11.

The effect SABS have on fish populations include:

1. Behavioral effects, such as inability to see prey or feed normally;

2. Physiological effects, such as gill clogging; and

3. Effects due to sediment deposition, such as burial and suffocation of eggs and larvae.

In terms of the three enclaves, Pak Lap Wan is home to a healthy amphioxus community whilst in So Lo Pun the Ecologically Important Stream (EIS) and its adjoining freshwater marsh support a healthy and natural population of Oryzias curvinotus, all of which will be highly susceptible to the effects of SABS.

How does this relate to the enclaves

The full extent of the problem can be seen when the Proposed Land Use map for each of the enclaves in the Draft Outline Zoning Plan is overlain onto the Hong Kong Geological Survey Map of each of the enclaves, as is done below:

Proposed Land Uses – Figure 11 - Draft Hoi Ha OZP


Overlay of Proposed Land Uses map on
Hong Kong Geological Survey map of Geology at Hoi Ha


Land Use Proposal – Plan 1 - Draft Pak Lap OZP


Overlay of Land Use Proposal map on
Hong Kong Geological Survey map of Geology at Pak Lap


Proposed Land Uses – Figure 12 - Draft So Lo Pun OZP


Overlay of Proposed Land Uses map on
Hong Kong Geological Survey map of Geology at So Lo Pun


Summary

To summarise this information:

1. On-septic tanks and soakaway pits (STS) systems will not work in Hoi Ha, Pak Lap or So Lo Pun because the underlying geology will not support their use;

2. Each of the proposed development areas in these three enclaves is susceptible to alluvial flooding because of the underlying geology, which even according to the governments own guidelines means STS systems cannot be used in such areas;

3. Buffer zones will not separate the discharges from STS systems from the streams, no matter how great the distance, because the groundwater in the alluvial deposits are hydraulically connected to the water in the stream, which means they are not separate, but are part of the same interconnected system;

4. The use of STS systems in these enclaves also poses an unacceptable health risk. One of the strategies for preventing the spread of a global pandemic from Hong Kong is environmental hygiene, something which using STS systems in these enclaves threatens. On this matter, understanding the implications of the following information is critically important - H7N9 bird flu may be spreading through human faeces and this has important implications on the infection control strategies for the virus, as the influenza virus in stools may contaminate the surrounding environment;

5. The use of STS systems in these enclaves also poses an unacceptable risk to the environment, as wastewater will neither be filtered nor buffered as proposed in the government guidelines, with potentially devastating consequences for the environment.

It should be noted, these issues are not confined to these three enclaves. Similar issues are evident in Tai Long Sai Wan and are likely to be present in most of the enclaves under threat of development. This is not selective criticism, it is a straight forward question of geography and the siting of human habitation.

Conclusion

In short, the government needs to find an alternative solution to the use of on-septic tanks and soakaway pits (STS) systems in Hoi Ha, Pak Lap and So Lo Pun and any other enclaves which are situated in similar circumstances.

References

1See EPD Document “Guidance Notes on Discharges from Village Houses”:

2See para 82 of the Minutes of 1032nd  Meeting of the Town Planning Board held on 26.4.2013:

3Hong Kong Geological Survey map. Sheet 8 – Sai Kung.

4Hong Kong Geological Survey map. Sheet 12 – Clear water Bay.

5Hong Kong Geological Survey map. Sheet 3 – Sheung Shui.

6Mckenzie,A.A, Bloomfield, J.P, Hulbert, A and Rutter H.K, 2010. Confidence and Groundwater Flood Susceptibility Mapping. [online]  British Geological Survey. Available at:
ncg.nuim.ie/gisruk/materials/proceedings/PDF/6B2.pdf

7Septic System Impact of Surface Waters. 2005. Tri-State Water Quality Council.

8H7N9 bird flu may be spread through human faeces, research suggests. [online]. SCMP. 15 August 2013 Available at:

9Septic System Impact on Surface Waters – A review for the Inland Northwest. 2005. [online] Tri-State Water Quality Council. Available at:

10What are Suspended and Bedded Sediments (SABS)? [online] 2003. US Environmental Protection Agency. Available at:  http://water.epa.gov/scitech/datait/tools/warsss/sabs.cfm

11Suspended Sediment in Hong Kong Waters.GEO Report No. 106.[online] By S. Parry.CEDD HKSAR Government. November 2000. Available at:  http://www.cedd.gov.hk/eng/publications/geo_reports/doc/er106.pdf

Note

Hong Kong Geological Survey maps are available from the Maps Publication Centre, Survey and Mapping Office, 23/F, North Point Government Offices, 333 Java Road, North Point, Hong Kong. 

Friday 22 November 2013

Hoi Ha Wan highest ranking soft shore in Hong Kong in terms of biodiversity

In 2006 a Study on the Soft Shore in Hoi Ha Wan Marine Park was published1 which identified the soft shore of HHWMP as an ecologically important habitat, as it supports the highest number of species (in terms of Polychaeta, Crustacea and Mollusca) when compared with 40 other soft shores in Hong Kong and is thus the highest ranking soft shore among 40 other soft shores in Hong Kong in terms of biodiversity. 

The following diagram shows the study area:


Literature review

The following is an extract from the study and documents the literature review undertaken for the Biodiversity Survey:

2.1. Biodiversity survey

A comprehensive literature review on relevant studies was conducted to establish a species list of the flora and fauna observed in the HHWMP soft shore in the past (Table 1). The sampling locations of previous studies have been renamed to correspond to Sections A – D of the present study, as described previously in Section 1.3. A total of 22 surveys have been conducted in HHWMP, covering subtidal, sandy shore, freshwater stream, rocky shore and mangrove habitats.

Sections A and B have received the most research attention, while Sections D and E have received the least research effort, in which only two Ocypode sp. (ghost crab) and two Oligochaeta species have been reported. A total of 309 species have been found including five mangrove plant species, nine algal species, one protozoan species, and the remaining were animal species. Terrestrial fauna comprised mainly insects (24 species) and gastropods (6 species), which were all found in section B. To discount these terrestrial species, a total of 264 marine macrobenthos could be observed at the HHW soft shore and they could be divided into five major taxonomic groups including Mollusca (114 species), Crustacea (28 species), Polychaeta (70 species) and Oligochaeta (32 species). Dominant marine species included bivalves Musculista senhausia, nerites Clithon oualaniensis, Ostracods, polychaete Family Nereidae, Eusyllis sp. and Aonides sp., and flatworms (Table 1). Other taxonomic groups included Cnidaria (2 species), Porifera (1 species), Nemertea (8 species), Nematoda (1 species), Platyhelminthes (1 species) and Echinodermata (7 species).

Table 1. Flora and fauna recorded in the soft shore at the Hoi Ha Wan Marine Park (Note: the abundance recorded in Shea (1992) represents total number of individuals in his sampling. It can, therefore, be used to indicate relative abundance only; the abundance in Sundberg et al. (1992) and Liu (1992) were expressed as number per 0.00175 m3 and number per 0.25 m2, respectively)

Taxa. Sampling location. Abundance

PROTOZOA
Foraminifera Section B (sandy shore) 1q

CNIDARIA
Hydrozoa
Hydra sp. Section B (estuary area) 3q
Anthozoa
Anthopleura japonica Rocky shores (western side) 18m

INSECTA
Ephemeroptera
Baetis spp. Section B (upper stream) 79q
Caenis Section B (upper stream) 5q
Chorotepes sp. Section B (upper stream) 5q
Cinygmina sp. Section B (upper stream) 9q
Indobaetis sp. Section B (upper stream) 25q
Paegniodes cupulatus Section B (upper stream) 3q
Procloeon sp. Section B (upper stream) 57q
Pseudocleon Section B (upper stream) 51q
Plecoptera
Neoperla sp. Section B (upper stream) 1q
Coleoptera
Elmidae Section B (upper stream) 2q
Psephenoides sp. Section B (upper stream) 5q
Hemiptera
Corixidae Section B (upper stream) 3q
Tricoptera
Anisocentropus maculates Section B (upper stream) 11q
Cheumatopsyche Section B (upper stream) 1q
Coerodes hongkongensis Section B (upper stream) 2q
Hydroptilidae Section B (upper stream) 1q
Diptera
Ceratopogonidae Section B (upper stream) 2q
Chironominae Section B (upper stream, stream mouth and sandy shores) 144, 12, 60q
Empididae Section B (upper stream) 6q
Orthocladiinae Section B (upper stream) 54q
Similium Section B (upper stream) 12q
Tanypodinae Section B (upper stream) 18q
Tipulidae Section B (upper stream) 7q
Collembola Section B (upper stream) 1q

MOLLUSCA
Bivalvia
Atactodea striata Section B (sandy shore) 1q
Circe sp. Section B (stream mouth) 4q
Donax cuneatus Section B (stream mouth and sandy shores) 15, 27q
Donax faba Section B (stream mouth) 7q
Isognomon ephippium Rocky shores (west side) 23m
Musculista senhausia Section B (stream mouth and sandy shores) 127, 151q
Pinna bicolor Subtidal NAn
Saccostrea cucullata Rocky shores (eastern and western sides) 34n
Tapes philippinarum Section B (sandy shore) 2q
Tapes variegatus Section B (stream mouth and sandy shores) 1, 3q
Mesodesmatidae sp. Section B (stream mouth) 1q
Gastropoda
Nudibranchia
Armina punctilopsis No specified locations indicated NAl
Chromodoris lineolata Subtidal NAq
Chromodoris orientalis Subtidal NAq
Chromodoris rubrocornuta Subtidal NAq
Chromodoris sinensis Subtidal NAq
Glossodoris atromarginata Subtidal NAp
Glossodoris cincta Subtidal NAp
Gymnodoris inornata Subtidal NAq
Hypselodoris festiva Subtidal NAp
Hypselodoris maritime Subtidal NAp
Hypselodoris placida Subtidal NAp
Kaloplocamus acutus Subtidal NAq
Lamellana gymnota No specified locations indicated NAl
Noumea nivalis Subtidal NAq
Nudibranchia species Section B (sandy shore) 1q
Thiaridae
Brotia hainanensis Section B (upper stream) 2q
Melanoides tuberculata Section B (upper stream) 3q
Thiara scabra Section B (stream mouth) 31q
Assimineidae
Assiminea sp. Section B (stream mouth) 15q
Planorbidae
Ferrissia baconi (stream limpet)
Section B (upper stream) 7q
Scaphandridae
Eocylichna soyoae Section B (stream mouth) 1q
Fissurellidae
Diodora cruciata No specified locations indicated NAj
Scutus unguis No specified locations indicated NAj
Patellidae
Cellana luchuana No specified locations indicated NAj
Cellana toreuma Rocky shores (eastern and western sides) 1m
Cellana toreuma No specified locations indicated NAj
Collisella luchuana Rocky shores (eastern side) 1m
Acmaeidae
Patelloida pygmaea Section B (sandy shores) 2q
Patelloida pygmaea Rocky shores (eastern and western sides) 39m
Patelloida pygmaea No specified locations indicated NAj
Siphonarridae
Siphonaria atra Rocky shores (eastern and western sides) 10m
Siphonaria japonica Rocky shores (eastern and western sides) 4m
Siphonaria sirius Rocky shores (eastern and western sides) 7m
Trochidae
Chlorostoma argyrostoma No specified locations indicated NAj
Clanculus margaritarius No specified locations indicated NAj
Euchelus scaber No specified locations indicated NAj
Hybochelus sp. No specified locations indicated NAj
Monodonta labio Rocky shores (eastern and western sides) 14m
Monodonta labio No specified locations indicated NAj
Tectus maculatus No specified locations indicated NAj
Tectus pyramis No specified locations indicated NAj
Turbinidae
Clithon oualaniensis No specified locations indicated NAj
Dentarene loculosa No specified locations indicated NAj
Liotina sp. Section B (sandy shore) 4q
Lunella coronata Section B (stream mouth) 2q
Lunella coronata Rocky shores (eastern and western sides) 6m
Lunella coronata No specified locations indicated NAj
Neritidae
Clithon oualaniensis Section B (stream mouth and sandy shores) 179, 195q
Clithon retropictus Section B (upper stream and stream  mouth) 2, 3q
Nerita albicilla Rocky shores (eastern and western sides) 8m
Nerita albicilla No specified locations indicated NAj
Nerita chamaeleon Rocky shores (eastern side) 5m
Nerita chameleon No specified locations indicated NAj
Nerita polita No specified locations indicated NAj
Nerita squamulata No specified locations indicated NAj
Littorinidae
Littoraria articulata Section B (stream mouth) 1q
Littoraria articulata Rocky shores (west side) 1m
Littoraria articulata No specified locations indicated NAj
Littoraria brevicula No specified locations indicated NAj
Littoraria melanostoma No specified locations indicated NAj
Nodilittorina exigua Rocky shores (east and west sides) 5m
Nodilittorina radiata No specified locations indicated NAj
Nodilittorina vidua No specified locations indicated NAj
Nodillittorina pyramidalis Rocky shores (east side) 3m
Paesiella infracostata No specified locations indicated NAj
Paesiella lutulenta No specified locations indicated NAj
Paesiella roepstorffiana Section B (stream mouth) 6q
Paesiella roepstorffiana Rocky shores (east and west sides) 11m
Paesiella roepstorffiana No specified locations indicated NAj
Rissoidae
Phosinella sp. No specified locations indicated NAj
Rissoa sp. No specified locations indicated NAj
Turritellidae
Turritella bacillus subtidal NAj
Cerithiidae
Cerithium sp. No specified locations indicated NAj
Clypeomorus
batillariaeformis
No specified locations indicated NAj
Planaxidae
Planaxis sulcatus Rocky shores (eastern and western sides) 6m
Planaxis sulcata No specified locations indicated NAj
Potamididae
Batillaria carbonarium Rocky shores (west side) 4m
Batillaria carbonarium No specified locations indicated NAj
Batillaria multiformis Rocky shores (west side) 8m
Batillaria sordida Rocky shores (west side) 11m
Batillaria sordida No specified locations indicated NAj
Batillaria zonalis No specified locations indicated NAj
Cerithidea cingulata Section B (stream mouth) 54q
Cerithidea rhizophorarum No specified locations indicated NAj
Clypermorus brevis Rocky shores (west side) 10m
Terebralia sulcata Section B (stream mouth) 1q
Terebralia sulcata No specified locations indicated NAj
Calyptraeidae
Crepidula onyx No specified locations indicated NAj
Strombidae
Strombus luhuanus No specified locations indicated NAj
Strombus urceus No specified locations indicated NAj
Strombus vittatis No specified locations indicated NAj
Naticidae
Natica gualtieriana No specified locations indicated NAj
Polinices tumidus No specified locations indicated NAj
Cymatiidae
Linatella caudate No specified locations indicated NAj
Bursidae
Bursa rana No specified locations indicated NAj
Triphoridae
Viriola tricincta No specified locations indicated NAj
Eulimidae
Parvioris fulvescens No specified locations indicated NAj
Parvioris mortoni No specified locations indicated NAj
Muricidae
Chicoreus brunneus No specified locations indicated NAj
Chicoreus microphyllus No specified locations indicated NAj
Murex trapa No specified locations indicated NAj
Thaididae
Cronia margariticola No specified locations indicated NAj
Drupella rugosa No specified locations indicated NAj
Morula granulata No specified locations indicated NAj
Morula musiva Rocky shores (east and west sides) 6n
Morula musiva No specified locations indicated NAj
Thais clavigera Rocky shores (east and west sides) 8m
Thais clavigera No specified locations indicated NAj
Buccinidae
Babylonia areolata No specified locations indicated NAj
Babylonia lutosa No specified locations indicated NAj
Engina menkaena No specified locations indicated NAj
Pyrenidae
Pyrene bicincta No specified locations indicated NAj
Nassariidae
Nassarius celebensis No specified locations indicated NAj
Nassarius crematus No specified locations indicated NAj
Nassarius festivus No specified locations indicated NAj
Nassarius festivus No specified locations indicated NAb
Nassarius livescens No specified locations indicated NAj
Nassarius siquijorensis No specified locations indicated NAj
Fasciolariidae
Perisernia sp. No specified locations indicated NAj
Mitridae
Mitra aurantia No specified locations indicated NAj
Pterygia crenulata No specified locations indicated NAj
Turridae
Inquisitor flavidula Subtidal NAj
Lophitoma leucotropis Subtidal NAj
Turricola nelliae Subtidal NAj
Architectonicidae
Architectonica perspective Subtidal NAj
Pyramidellidae
Turbonilla sp. 1 No specified locations indicated NAj
Turbonilla sp. 2 No specified locations indicated NAq
Cephalaspidea
Philine orientalis Section B (sandy shore) 1q
Philine orientalis Section B (sandy shore) NAs

CRUSTACEA
Copepoda spp. Section B (streams, stream mouth, sandy shore) 92, 8, 51q
Cladocera spp. Section B (upper stream) 72q
Ostracoda spp. Section B (upper stream) 361q
Amphipoda Section B (stream mouth and sandy shores) 43, 83q
Tanaideacea Section B (stream mouth and sandy shores) 10, 1q
Cirripedia
Balanus albicostatus Rocky shores (western side) 13m
Pollicipes mitella Rocky shores (eastern side) 10m
Tetraclita japonica Rocky shores (eastern side) 1m
Isopoda
Oniscidea Mangroves NAk
Decapoda
Anchistus custos Subtidal (commensal with Pinna bicolor)
NAn
Charybdis truncata Subtidal NAd
Charybdis vadorum Subtidal NAd
Charybdis variegatus Subtidal NAd
Conchodytes monodactylus Subtidal (commensal with Pinna bicolor)
NAn
Hermit crabs Section B (stream mouth) 1q
Ocypode ceratophthalma Section, A, B, C and D NAf
Ocypode cordimana Section, A, B, C and D NAf
Portunus hastatoides Subtidal NAd
Scopimera globosa Section B (stream mouth) NAf
Scopimera intermedia Section B (stream mouth) 2q
Sesarma pictum Section B and C NAf
Tmethypocoelis ceratophora Section B (stream mouth) NAf
Tmethypoecoelis
ceratophora
Section B (stream mouth) 2q
Uca chlorophthalmus Section B, C (mangroves) NAf
Uca crassipes No specified locations indicated NAi
Uca lactea Section B (stream mouth) NAf
Uca lactea No specified locations indicated NAi
Acarina
Water mites Section B (upper stream and stream mouth) 52, 6q
Agauopsis ammodytes High shore level at sandy shores (15-20 cm sediment depth) 8
Agauopsis arenaria High shore level at sandy shores (15-20 cm sediment depth) 15

PORIFERA
Siphonochalina flexa Subtidal NAo

ANNELIDA
Polychaeta
Aonides sp. Section A, B and C 61, 132, 4r
Aricidea sp. Section B 2r
Armandia sp. Section A 1r
Boccardiella sp. Section B 2r
Brania sp. Section A 14r
Capitella sp. Section A and C 1, 5r
Capitellidae sp. Section B 4r
Caulleriella sp. Section C 2r
Ceratonereis sp. A Section A, B and C 40, 3, 15r
Ceratonereis sp. B Section C 1r
Chrysopetalidae Section A and B 1, 1r
Cirratulidae Section B (sandy shores) 2q
Cirratulidae sp. Section A 1r
Cirriformia sp. A Section A and B 35, 11r
Cirriformia sp. B Section A and B 4, 2r
Cirriformia sp. C Section A 1r
Dorvillea sp. Section B 2r
Dorvilleidae sp. Section A 2r
Ehlersia sp. A Section A and B 25, 8r
Ehlersia sp. B Section A and C 20, 7r
Eulalia sp. Section B 7r
Eusyllinae sp. A Section A 30r
Eusyllinae sp. B Section B 1r
Eusyllis sp. Section A, B and C 753, 138, 71r
Galathowenia sp. Section A 3r
Glycera sp. Section B 1r
Glycinde sp. Section A, B and C 1, 2, 1r
Goniadides sp. Section B and C 18, 2r
Gonionidae Section B (stream mouth and sandy shores) 1, 9q
Harmothoe sp. Section A and B 2, 3r
Hesionidae Section B (stream mouth and sandy shores) 3, 13q
Linopherus sp. Section A, B and C 33, 53, 1r
Malacoceros sp. Section C 2r
Micronephthys sp. Section A, B and C 13, 20, 35r
Micropodarke sp. Section A, B and C 122, 31, 3r
Nephtyidae Section B (sandy shores) 1q
Nephtys sp. Section A, B and C 1, 7, 6r
Nereidae Section B (upper stream, stream mouth and sandy shores) 134, 5, 2q
Nereiphylla sp. Section B 1r
Ougia sp. Section A 4r
Paralacydonia sp. Section A and B 1, 1r
Paramphinome sp. Section B 1r
Perinereis sp. Section A 1r
Pettiboneia sp. Section A 8r
Pholoe sp. Section B 1r
Pionosyllis sp. B Section B 5r
Pisione sp. Section B 2r
Podarke sp. A Section A and B 2, 1r
Podarke sp. B Section B 1r
Podarkeopsis sp. Section A and B 2, 1r
Poecilochaetus sp. Section A 1r
Polydora sp. Section B 1r
Polygordius sp. Section B 3r
Prionospio sp. A Section A and B 1, 1r
Prionospio sp. B Section A, B and C 2, 1, 2r
Prionospio sp. C Section A and B 2, 2r
Protodorvillea sp. Section B 3r
Pseudopolydora sp. A Section A, B and C 1, 4, 5r
Pseudopolydora sp. B Section A and B 1, 5r
Saccocirrus sp. Section C 1r
Scolelepis sp. A Section B 3r
Scolelepis sp. B Section A, B and C 5, 1, 2r
Sigambra sp. Section A and B 2, 2r
Sphaerosyllis sp. Section A, B and C 2, 6, 1r
Spionidae Section B (stream mouth and sandy shores) 5, 25q
Syllidae Section B (stream mouth and sandy shores) 1, 92q
Syllides sp. Section A 5r
Tharyx sp. Section A 8r
Typosyllis sp. A Section B and C 24, 3r
Typosyllis sp. B Section A and B 13, 5r
Oligochaeta
Ainudrilus lutulentus Section B NAh
Aktedrilus cuneus Section C 6r
Aktedrilus longitubularis Section B and C 3, 16r
Aktedrilus mortoni Section A, B and C 2, 7, 68r
Aquatic oligochaetes Section B (upper stream, stream mouth and sandy shores) 41, 28, 38q
Bathydrilus edwardsi East side of the bay NAh
Bathydrilus keenai Subtidal NAh
Heronidrilus bihamis Section A, B and C 2, 24, 45r
Heterodrilus bihamis Subtidal NAh
Limnodrilus rubicundus Section C 1r
Limnodrilus tenuiductus Section C 7r
Limnodrilus toloensis Section C 4r
Marionina coatesae Section B 1r
Marionina coatesae Section A, B and E NAh
Marionina levitheca Section B and C 2, 14r
Marionina levitheca Section A NAh
Marionina nevisensis Section C 45r
Marionina nevisensis Secion A NAh
Paranais litoralis Section E NAh
Paranais plenus Section A and B NAh
Paranais sp. Section A 2r
Pectinodrilus disparatus Section A and C 7, 126r
Pectinodrilus hoihaensis Section C 42r
Pectinodrilus molestus Section B and C 2, 2r
Phallodrilus vanus Subtidal NAh
Phallodrilus vanus East side of the bay NAh
S. sterreri Section A and C 1, 1r
Smithsonidrilus irregularis Section B 1r
Smithsonidrilus tenuiculus Section A NAh
Smithsonidrilus tuber Section C 14r
Stephensonella marina Section C 3r
Tubificidae sp. Section A 1r
Uniporodrillus furcatus Section A, B and C 2, 5. 6r

NEMERTEA
Callinera sp. Section B and C 1, 1r
Cephalotrix sp. Section B 1r
Euosia verticivarius Section A, B and C 4, 1, 1r
Heteronemertea sp. A Section B 2r
Heteronemertea sp. A Section B 1r
Hoplonemertea sp. Section A 1r
Palaeonemertea sp. A Section A and B 7, 2r
Palaeonemertea sp. B Section B 1r
Procephalotrix arenarius Section A, B and C 33, 41, 36r

NEMATODA
Aquatic nematodes Section B (upper stream, stream mouth and sandy shores) 1, 29, 6q

PLATYHELMINTHES
Turbellaria
Flatworm Section B (upper stream, stream mouth and sandy shores) 4, 14, 162q

ECHINODERMATA
Anthocidaris crassispina Subtidal, rocky substratum on the west side of the bay NAe
Diadema setosum 2 m underwater NAg
Parasalenia gratiosa Subtidal NAt
Salmacis sphaeroides Subtidal NAt
Temnopleurus reevesi Subtidal Nat
Ophiuroidea
Ophioplocus imbricatus 1-2 m underwater NAg
Holothurioidea
Holothuria leucospilota 1 m underwater Nag

MANGROVE PLANTS Per m2
Acanthus Section A1 and B 8, 75c
Aegiceras corniculatum Sections A1, A2 and B 272, 263, 298c
Avicennia marina Section A1 1c
Excoecaria agallocha Sections A1, A2 and B 14, 7, 5c
Kandelia candel Sections A1, A2 and B 116, 7, 2c

ALGAE
Brachytrichia maculans Rocky shores (east and west sides) NAm
Colpomenia sinuosa Rocky shores (east side) NAm
Corallina Rocky shores (east side) NAm
Gelidium divaricatum Rocky shores (east and west sides) NAm
Gomontia Rocky shores (east side) NA1
Hildenbrandtia prototypes Rocky shores (east and west sides) NAm
Monostroma nitidum Rocky shores (east side) NAm
Sargassum hemiphyllum Rocky shores (east side) NAm
Ulva Rocky shores (east and west sides) Nam

Remarks: species names are cited ad verbatim to avoid confusion
a Bartsch 1992; b Chan & Morton 2001; c Chan 1992; d Cheung 1986; e Chiu 1988; f Choi 1992;
g Clark 1982; h Erseus 1984; i Jones & Morton 1994; j Knudsen 1992; k Li 2003; l Lin 1992; m Liu
1992; n Morton 1987; o Pulitzer-Finale 1982, p Rudman & Darvell 1990; q Shea 1992;
r Sundberg et al. 1992; s Taylor & Jensen 1992; t Thompson 1982

Reference

1Leung KMY, Lui KKY, Wai TC, Cheung YT, Chan BKK, Yau C (2006). Study on the Soft Shore in Hoi Ha Wan Marine Park. Final Report to the Agriculture, Fisheries and Conservation Department (AFCD/SQ/2/05), the Government of the HKSAR, P.R. China.