6. ECOLOGY

6.1 Introduction

6.1.1 The EIA concluded that the Project has avoided and minimised much of the environmental and ecological impacts by adopting the preferred option. The habitats to be lost would be small in size and not of high ecological value. Compensatory landscape tree planting consisting mostly of native species and compensatory mangrove planting will be provided to mitigate the loss, and the residual impact is considered acceptable.

6.2 Monitoring and Audit during Construction Phase

6.2.1 No specific ecological monitoring is necessary during construction.

6.2.2 The recommended mitigation measures should be audited at least once every week as part of the site audit programme. The weekly site audit undertaken by the Environmental Team (ET) should include checking whether the good site practices and precautionary measures are being properly implemented by the Contractor.

6.2.3 The extent of the works area should be checked by the ET during the weekly site audit. Any trespass by the Contractor outside the works area especially any damage to the mangroves and stream bed that are earmarked for retention and the intertidal mudflats outside the Project area should be reported to the Engineer. In particular, the ET should check whether the retained mangroves are properly fenced off and are not adversely affected by construction works. In the event such non-compliance are found, the relevant Event / Action Plans should be implemented.

6.3 Event and Action Plan for Ecology during Construction Phase

6.3.1 In the event of non-compliance is found during site audit, the Event/Action Plans shown in Table 6.1 should be followed by the relevant parties.

Table 6.1

Event/Action Plan for Ecology during Construction Phase

EVENT	ACTION
	ET Leader	IEC	Engineer	Contractor
Non-conformity on one occasion	1. Identify source 2. Inform the IEC and the ER 3. Discuss remedial actions with the IEC, the ER and the Contractor 4. Monitor / audit / review remedial actions until rectification has been completed	1. Check monitoring / auditing results 2. Check the Contractor’s working method 3. Discuss with the ET and Contractor on possible remedial measures 4. Advise the ER on effectiveness of proposed remedial measures 5. Check the implementation of remedial measures	1. Notify Contractor 2. Ensure remedial measures are properly implemented 3. Consider and instruct, if necessary, the Contractor to slow down or to stop all or part of the works in the case of serious non-conformity until situation is rectified	1. Take immediate action to avoid further problem 2. Amend working methods if needed 3. Submit proposals for remedial actions to ET, ER and IEC 4. Rectify damage and implement the agreed remedial actions
Repeated Non-conformity	1. Identify source 2. Inform the IEC, ER, EPD and AFCD 3. Increase monitoring / auditing frequency 4. Discuss remedial actions with the IEC, the ER and the Contractor 5. Monitor / audit / review remedial actions until rectification has been completed 6. If exceedance stops, cease additional monitoring / auditing	1. Check monitoring / auditing results 2. Check the Contractor’s working method 3. Discuss with the ET and Contractor on possible remedial measures 4. Supervise the implementation of remedial measures 5. Advise the ER on effectiveness of proposed remedial measures and keep EPD and AFCD informed	1. Notify Contractor 2. Ensure remedial measures are properly implemented 3. Consider and instruct, if necessary, the Contractor to slow down or to stop all or part of the works in the case of serious non-conformity until situation is rectified	1. Take immediate action to avoid further problem 2. Amend working methods if needed 3. Submit proposals for remedial actions to ET, ER and IEC 4. Rectify damage and implement the agreed remedial actions

6.4 Monitoring and Audit during Operation Phase

Background

6.4.1 To mitigate the loss of 0.07 ha of mangrove patches, a total of 0.07 ha (1:1 ratio), mainly of newly formed surface at the northern part of the downstream section of the channel is identified for compensatory mangrove planting. Upon completion of construction, the mangrove compensation area will be filled with mud of at least 60 cm in depth to be collected from suitable stream bed material excavated during construction, the abandoned fish pond, or mudflat outside the project area. The final level of the planted area should be about 1-2 mCD. Mangrove species to be planted will include Kandelia obovata at about 1-1.5 mCD and Acanthus ilicifolius at about 1.5-2 mCD, the major species found at the site. Mangrove seedlings of at least 60 cm in height purchased at Futian or Mai Po Nature Reserve should be planted at 1 m spacing.

6.4.2 Monitoring of the compensatory mangrove planting is recommended.

Objectives

6.4.3 The objectives of the monitoring is to monitor the density, growth, health condition and survival rate of the compensatory mangrove planting as well as to recommend timing actions to rectify any unacceptable impacts.

Monitoring Methodology

6.4.4 Monitoring should be carried out by a suitable qualified ecologist employed by the project proponent. Monitoring should be conducted once every quarter for two years after completion of the mangrove planting.

6.4.5 The information provided below is a general indication of the monitoring requirement. Detailed monitoring proposals and schedules should be developed and agreed with EPD and AFCD prior to commencement of the monitoring.

6.4.6 The equipment to be used to monitor the growth of the mangrove seedlings should include, but not limited to, the following:

· ruler (retractable metallic measuring tape or soft measuring tape); and

· camera.

6.4.7 Five quadrats of 5m x 5m in size, should be randomly chosen for monitoring. The species and number of mangrove planting should be counted within each quadrat and the height and trunk diameter of 5 representative individuals within each quadrat should be measured.

6.4.8 The state of health (Good / Fair / Poor) and the rate of survival of the mangroves after planting should be estimated by visual observation.

6.4.9 Should the overall survival rate of each mangrove species be lower than 75%, replanting should be implemented by the Contractor under the landscape establishment works contract.

6.4.10 Monitoring should, preferably be, undertaken during low tide to allow safe access and to identify quadrat location.

6.4.11 Photographs of the mangrove compensation area and each quadrat should be taken. Other site conditions and observations should also be recorded.

6.4.12 Results of the mangrove monitoring should be submitted to EPD (and copied to AFCD) within 10 working days after each monitoring. A final report summarizing the monitoring results over the entire operational monitoring period and its findings should be prepared to serve as a reference for future similar projects.

6.5 Ecological Mitigation Measures

6.5.1 The aims of the ecological impact assessment are to protect, maintain or rehabilitate the natural environment, in particular, recognised sites of conservation importance and other ecological sensitive areas. The assessment has identified and quantified the potential ecological impacts associated with the Project. Measures to avoid, minimize and mitigate impacts are discussed below.

Impact Avoidance

6.5.2 The layout of the preferred option had avoided the mangroves at the lower reach of the Hang Hau Tsuen stream.

6.5.3 Good site practices and precautionary measures should be implemented to avoid encroachment onto the nearby natural habitats, minimise disturbance to wildlife, and ensure good water quality. Examples of water quality mitigation measures are detailed in Section 4.9 of this EM&A Manual (and Section 5.7 of the EIA report). Other precautionary measures include:

· Temporary fencing should be erected along the portion of the mangroves proposed to be retained to form protection zones to restrict access by construction workers or equipment or works. Unnecessary felling of the mangroves within these protection zones is prohibited. Signage should be provided at conspicuous location to warn workers from entering and disturbing these zones.

· All workers should be regularly briefed to avoid disturbing the flora and fauna near the works area.

· Surface run-off and wastewater from construction sites should be discharged into water bodies via adequately designed silt removal facilities such as sand traps, silt traps and sediment basins.

· Open stockpiles susceptible to erosion should be covered with tarpaulin or similar fabric and provided with containment such as bunds, sand bag barriers or equivalent measures, especially during the wet season (April – September) or when heavy rainstorm is predicted.

· Excavation works within the existing stream section should be programmed to be carried out during periods of low flow (dry season from 1st October to 31st March) as far as practicable to minimise impacts on downstream water quality and sensitive receivers. The excavation area should be limited to section of half width of the stream in order to maintain continuous water flow within the stream during the construction phase.

· Sewage arising from construction workers on site should be collected in a suitable storage facility, such as portable chemical toilets and disposed via licensed contractors.

Impact Minimisation

6.5.4 The site boundary of the Project has been limited to high disturbed area including built-up area and wasteland. Although of low ecological value, only section of the abandoned fish pond within the site boundary will be resumed, while the remaining portion of the pond will be preserved. The loss of mangrove has also been minimised as much as possible, while maintaining the necessary flood conveyance capacity and channel design.

Impact Mitigation

6.5.5 The impact during both construction and operation phases are anticipated to be minimal. However, compensatory landscape tree planting and compensatory mangrove planting and good site practices are recommended to mitigate the impacts.

6.5.6 The channel layout has been designed to retain as much trees as possible. To mitigate the loss of 16 trees, 114 nos. of new trees in heavy standard size will be planted within the site. The proposed trees consisting mostly of native species will include Celtis sinensis, Cinnamomum parthenoxylon, Ficus microcarpa, Hibiscus tiliaceus and Cassia siamea. The total aggregated girth size of compensatory trees of 8.55 m is more than the felled 3.59 m. Therefore, loss of tree will be compensated with a ratio of more than 1:1 in terms of numbers and aggregated girth size.

6.5.7 To mitigate the loss of 0.07 ha of mangrove patches, a total of 0.07 ha, mainly of newly formed surface at the northern part of the downstream section of the channel is identified for compensatory mangrove planting (Figure 7.3 of the EIA). Therefore, loss of mangrove will be compensated with a ratio of 1:1. Upon completion of construction, the mangrove compensation area will be filled with mud of at least 60 cm in depth to be collected from suitable stream bed material excavated during construction, the abandoned fish pond, or mudflat outside the project area. The final level of the planted area should be about 1-2 mCD. Mangrove species to be planted will include Kandelia obovata at about 1-1.5 mCD and Acanthus ilicifolius at about 1.5-2 mCD, the major species found at the site. Mangrove seedlings of at least 60 cm in height purchased at Futian or Mai Po Nature Reserve should be planted at 1 m spacing. Upon completion of planting, monitoring for survival and growth should be conducted for two years during the operation phase. The monitoring of the compensatory mangrove will be implemented by the project proponent. It is anticipated that both the retained and the compensated mangrove in the mangrove zone (Figure 2.7; Figure 7.3 of the EIA) would need no maintenance in the long run.

6.5.8 Before commencement of the works, the Contractor should submit details of the mitigation measures to be implemented during construction stage as part of their working method statement to the Engineer for approval. This should also include the details of the mangrove planting. This should be reviewed by the Environmental Team Leader and verified by the Independent Environmental Checker.

6.5.9 During operation phase, management and maintenance of the channel bed should be limited to the minimum required to prevent flooding and ensure safety. The channel should be permitted to find (and adjust) its own low flow channel and natural changes in the deposition of silt, sand, rock should be tolerated except where a specific flooding or safety issue is identified. Environmental considerations for maintenance of the proposed channel (see Section 5.9 of the EIA) should be adopted.

6.5.10 Vegetation management within the channel should be restricted to removing of obstructions and preventing tree establishment, while the presence of vegetation should be tolerated as much as possible. If clearance of vegetation is required to prevent obstruction of water flow, where specific flooding or safety issues have been identified, this should be undertaken during the dry season. Expert advice from AFCD should be sought in case of doubt.

6.5.11 To further mitigate stream loss, a layer of approximately 100 mm thick original river bed material will be added on top of the rip-rap bedding of the dry weather flow channel to recreate a natural stream environment. This would allow recolonization of benthic communities and re-establishment of vegetation within the channel.

6.5.12 The implementation schedule for the recommended mitigation measures is presented in Appendix A.

6.5.13 If the above measures are not sufficient to restore the impacts to acceptable levels upon the advice of ET Leader, the Contractor shall liaise with the ET Leader on some other mitigation measures, endorsed by IEC and propose to ER for approval, and implement the mitigation measures.