Padma Multipurpose Bridge Project

c. Monitor area for these creatures to ensure they are well away from the piling site – scarethem away if they are two close to the site using pingersMigratory/Winter Birds36. Charland with their mudflats and sandy beaches are the major staging grounds for migratorybirds within the project area. During the construction period if construction activities coincide with themigratory birds that utilize this habitat, potential disturbance will occur. Construction activities, such aspilling, dredging and human traffic in the Charland has the potential to negatively affect Charlanddwelling animals, including migratory birds. As some uncommon and rare winter visitors (Comb Duck,Ruddy Shelduck, Grey Headed Lapwing, Black Headed Ibis, Indian River Tern, Long-LeggedBuzzard, Short Eared Owl, and Common Tern) are seen in Project area and breed in these Charland.Noise from different equipments, vehicles, and human traffic has the potential to disturb migratorybirds, compelling them to leave these areas. Noise and the movement of workers may also disturb themigratory birds, which may leave or change their flight route until the activities are over. Staginggrounds of birds have been identified during the field investigations. To reduce air noise levels,mitigation measures such as acoustic enclosure will be placed to cover the hammer and the exposedpile to reduce the air noise level. The air noise levels can be reduced to about 60 dB with thesemeasures to minimize potential impacts on birds.37. Impact on Other Fish and Aquatic Life: Based on the above discussion (Noise and VibrationImpacts due to Pile Driving), noise levels from vibratory pile driving are limited to near the source andare not expected to have any large-scale impact on aquatic habitats. Aquatic species close to the piledrivers may exhibit avoidance response and move away from the piling areas. Pile driving activitiesalso will not impact known important fish breeding areas (Figure 3-30), which are located about 10 kmupstream of the bridge alignment.38. Other Endangered Species: Other than Ganges river dolphin, fishing cat, gharial, turtles (Gangessoft-shell Turtle, Brown Roofed Turtle, and Median Roofed Turtle, etc.), terrestrial birds (brown fishowl, river lapwing, and black winged kite, etc.) are the endangered species found in Padma River,which might have potential major impacts. High noise level may influence their behavior, and they aretherefore likely to avoid the construction areas during the construction period. In order to avoidimpacts on these species, the construction works will be limited within the designated sites allocatedto the contractors. Regular monitoring of the worksite for animals trapped in, or in danger will be doneand contractor will use a qualified person to relocate the animal. Monitor work areas for endangeredreptile and bird species to ensure they are well away from the piling site – scare them away if they aretoo close to the site using pingers for reptiles. Acoustic enclosure will be placed to cover the hammerand the exposed pile to reduce the air noise. The air noise levels can be reduced to about 60 dB withthese measures.39. Surface Water Quality: Dredging operation, disposal of dredged materials during piling activities,materials from superstructure formworks and other activities, and solid waste will deteriorate waterquality in the river especially local turbidity at cutter heads. The indiscriminate disposal of dredgedmaterial in the river water will increase turbidity in the downstream water, which might causesignificant damage to breeding and spawning of fish and may pose threat to other aquatic species.40. Noise Quality from other Construction Activities: Noise quality during the main bridge constructionwill deteriorate due to the mobilization of equipments, construction materials/ vehicles, batch mixing,erection and casting, and welding. The overall impact of noise to the receptors will depend on theposition of equipments and their cumulative actions. Table 7-8 presents typical constructionequipments and their generated noise level at 15m away from source and Table 7-9 presents thevibration level at 30m away from source. These noise levels are above the acceptable standard ofGOB (75dBA during day and 70 dBA during night as applicable for industrial area and 70dBA duringday and 60 dBA during night for commercial area). However, the surrounding communities will remainfar (1-7km) from the main bridge construction sites and due to the extensive vegetation coverage inthe communities; the noise impact from construction equipments is thus expected within the standardlevel. However, construction workers and others will directly be exposed to these noise levels.Table 7-8: Construction Equipment Noise Emission Levels7-14