Proportion of turtles using these waters is limited to nesters at Kuala Linggi and Mariam Patah (~9% of all Malacca turtles). Water area represents <0.01% of internesting turtle home range area, and none of core internesting area. Impact Evaluation Based on the RIAM, the impact is considered to be minor negative. Criteria Score Rationale Importance 2 The spatial impacts range from Tg. Dahan area to Kuala Linggi. Magnitude -1 Impacts are minor Permanence 3 Permanent Reversibility 3 irreversible Cumulativity 1 Minor impacts Environmental Score -14 Description -B Minor negative impact 6.2.13 Painted Terrapins 6.2.13.1 Evaluation Framework The life cycle of the painted terrapin as described in Section 5-Painted Terrapins points to four key elements where development pressures may affect the population. These are: The adults in the estuary and riverine waters of Sg. Linggi; The period of the passage of the adult females from Sg. Linggi to the estuary and thereafter to the nesting beaches; The nesting beaches; and The hatching and return of the hatchlings to Sg. Linggi As is evident from the description in Section 5- Painted Terrapins has the biology and ecological needs of the species is not well understood; based on what is known and what may be concluded from similar species the following evaluation criteria listed in Table 6.49 are relevant. 6-164 62801230-RPT-02 Evaluation of Impacts and Mitigation Measures Table 6.49 Life cycle stages and potential development impact pressures. Stages of Life Cycle Development Pressure Adults in the estuary, lower river Salinity regime change Turbidity regime change Passage of adult females to the estuary and Salinity regime change nesting beaches Turbidity regime change Increased current speed Nesting beaches and hatchlings Change in sediment particle size Sedimentation Physical obstruction Net loss of beaches Lights Noise Return of the hatchlings to Sg. Linggi Salinity regime change Turbidity regime change Increased current speed One of the unique characteristics of B. borneoensis is that this species lives in the brackish and freshwater environments, but nests in marine/coastal beaches and riverine sandbanks. While B. borneoensis is able to tolerate salinity at some stages of its life cycle, Dunson & Moll (1980)/20/ and Davenport & Wong (1986)/21/ found that B. borneoensis is intolerant of long- term immersion in sea water. Davenport & Wong (1986) /21/ reported that the maximum salinity tolerance for juveniles lies between 25 and 50% sea water (i.e. 8.5 to 17 ppt). They respond to exposure to high salinity by not feeding, drinking, defaecating or urinating. On return to low salinities, they rapidly replace lost water by drinking. At this time there is nothing known about the impact of changes in turbidity or suspended solids on the behaviour or broad ecology of the painted terrapin. Any direct impact presumably would be related to a change in visual acuity and therefore reduced exposure to predators; indirect impacts are most likely as a result from impacts on food and other secondary sources. One approach is to use the national water quality criteria given the significantly higher background concentrations that occur in the nearshore that in this case can range up to 35 mg/L. 6.2.13.2 Construction Phase Key construction activities that are assessed that may affect the painted terrapins include: Turbidity Lights and noise Mortality from construction activities Much of the effects, such as siltation and a dramatic increase in suspended particles, will be on the water clarity, where it will be reduced due to the increased turbidity. The painted terrapins will venture into the sea for nesting during the Inter monsoon (IM) and Southwest monsoon (SW) periods. The suspended sediment plume predicted for SW monsoon and IM periods show that the areas of high SSC which are unsuitable for the painted terrapin are near the project site and not near the nesting sites as shown in Figure 6.109 and Figure 6.110. This will impact the painted terrapins that nest at Kuala Linggi to Tg. Serai only very slightly. 6-165 Figure 6.109 Exceedance of 25 mg/L excess TSS in % of time for SW monsoon (above) and inter monsoon (below). 6-166 62801230-RPT-02 Evaluation of Impacts and Mitigation Measures Figure 6.110 Phase 4: Exceedance of 50 mg/L excess TSS in % of time for SW monsoon (above) and Intermonsoon (below). Even though major project components such as reclamation and dredging, the construction of marine facilities and sewage treatment plants are carried out mostly in the sea and not on the beach, these activities will directly impact the movements of painted terrapins as well as erosion of the beaches along the coast. The access bridge and sewage treatment plant will be built at the estuary, nearby to where the painted terrapins have been reported to nest (Kuala Linggi and Tanjung Serai areas). The painted terrapins are extremely sensitive to any form of disturbances, especially to light. Lights from construction during the night may also deter or distract the movements of nesting terrapins as well as prevent the terrapins from nesting at beaches nearby. Noise from construction (Kuala Linggi -36 dBA; Tg. Serai-17 dBA) may also confuse the terrapins and prevent them from taking their normal route, exposing them to more dangers from predators. The most direct impact these activities will have on the painted terrapins is the potential obstruction posed by the access bridge to terrapin nesting beaches south of Sg. Linggi. The critical nesting beaches of the painted terrapins are as highlighted in the map in Figure 6.111. 6-167 Figure 6.111 B. borneoensis nesting beaches in the Linggi area, based on Sharma (1997) and personal communication with Dr. Reuben Sharma and Fardiansah, DOF Padang Kemunting. Three terrapin nesting beaches are located right at the estuary, and a few more nesting beaches down south. The construction of the access bridge (which will be connected to the shore) will take place right at the estuary. The reclamation (10 years) and piling works (1 year) of the proposed project will inevitably increase the level of underwater noise. Reclamation process uses TSHD dredgers during construction which produce sounds levels below 500 Hz with a maximum broadband source SPL at 189.9 dB re 1 µPa at 1 metre /22/. This impact is continuous throughout the project reclamation period. It is anticipated that the painted terrapin would avoid the area where the construction sound is generated beyond tolerance thresholds. Due to these disturbances during construction (which may last for 8 – 10 years), three nesting beaches (Kuala Linggi, Tg. Dahan and Tg. Serai) may not be feasible for painted terrapin to nest, because the painted terrapins, though similar to green turtles, are even more sensitive to disturbances and may avoid the area. The access bridge construction will take place for one year. For the remaining project development years, the terrapins may be impeded by the piled bridge structure and either take the long route to access the nesting beaches or face mortality along the way. 6-168 62801230-RPT-02 Evaluation of Impacts and Mitigation Measures The potential loss of access to three nesting beaches as well as the loss of beach material from the beach from Tg. Che’ Amat to Tg. Bt. Supai may directly cause the loss of nesting and egg productivity, and in long term, causes the decimation of the species due to low recruitment and survival rates. Since the painted terrapins may take up to 20 years to mature, these effects will not be seen immediately. Impact Evaluation Based on the RIAM, the impact is considered to be significant negative. Criteria Score Rationale Importance 3 The effect is limited to the distribution of B. borneoensis within 10 km from project boundary. Magnitude -2 The major construction activities will cause beach erosion at 1 nesting beach and loss of access to 3 nesting beaches out of 9 nesting beaches. Permanence 2 The noise and disturbances is temporary, confined to the construction stage, albeit over a 10 year period. Reversibility 3 Construction activities and sediment plume generated goes on for 10 years. However, it is possible that the turtles may decide not to go to those beaches any longer or faced mortality on its way there. Cumulativity 3 The loss of nesting beaches does not just affect the current breeding population of painted terrapins, but subsequent generations as well. It is cumulative since these impacts could possible impair the population growth of painted terrapins. Environmental Score -48 Description -D Significant negative impact 6.2.13.3 Operation Phase Key operational activities that are likely to affect the painted terrapins include: Water Levels Current Speed Ship traffic Salinity Permanent loss of beaches Oil Spill Beach nourishment (Tg. Che’ Amar to Tg. Bt. Supai) The access bridge is built on the beach where the painted terrapins have been reported to nest (Kuala Linggi and Tg. Serai areas). During operations, the access bridge may obstruct the movements of the painted terrapin from the river to the nesting beaches during the nesting season for behaviour reasons. However, there is space in between the piles for the movements of painted terrapins to access the 3 nesting beaches adjacent to the bridge if disturbance is not an issue. Phase 3 and 4 show that some sedimentation is expected east of the reclamation at expected value of 2 cm/year as shown in Figure 6.112. It is likely that some of this fine sediments with time will deposit in the existing beaches between Tg. Serai and Tg. Bt. Supai. Changes are, however, minor and not expected to affect the stability of the shoreline but it should be expected that the coastline will change its present sandy characteristics to a silty type since there will be an increase in the content of fine sediments in the beach.