TSHD definition
Examples of TSHD in a sentence
These assumptions are as follows: ◼ The assessment is based on the peak sediment release rate for grab /TSHD dredging, backfilling and capping.
It is assumed the backfilling of sediment from ▇▇▇▇▇▇ barge or TSHD would expose the sediment to the entire water column.
TSHD generally allows higher production rate for dredging and result in higher sediment loss and would be considered as a worst case condition for assessing cumulative impact.
The rate of release (in kg/s) of sediment for one TSHD working at the above maximum rate is calculated as follows: 𝐿𝑜𝑠𝑠 𝑅𝑎𝑡𝑒 (𝑘𝑔/𝑠) = 𝐷𝑟𝑒𝑑𝑔𝑒𝑑 𝐼𝑛 − 𝑠𝑖𝑡𝑢 𝑉𝑜𝑙𝑢𝑚𝑒 𝑝𝑒𝑟 𝐵𝑎𝑟𝑔𝑒 (𝑚3) × 𝐿𝑜𝑠𝑠 𝑅𝑎𝑡𝑒 (𝑘𝑔⁄𝑚3) ÷ 𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑝𝑒𝑟 𝑇𝑟𝑖𝑝 (𝑠) = 3050 𝑚3 × 7 𝑘𝑔⁄𝑚3 ÷ 1200 𝑠 Assuming a forward speed of 0.3 m/s during loading for the TSHD, the TSHD would move about 360 m forward in a 20-minute cycle.
During backfilling and capping works Contractor(s) / CEDD ✓ Air Pollution Control (Construction Dust) Regulation 9.8.2 S8.2 The sediments on board the ▇▇▇▇▇▇ barges / TSHD to be disposed of at the formed CMPs should be transported to the formed CMPs as soon as possible to minimise potential fugitive dust and odour emissions.
Thus the proposed scenario is very conservative; ◼ The proposed modelling scenarios cover the worst case in term of plant use (i.e. simulate ▇▇▇▇▇▇ barge disposal instead of TSHD); ◼ The modelled locations for dredging / backfilling / capping are selected such that the sediment sources are at its shortest distance from the nearest sensitive receivers.
According to the approved EIA of New Contaminated Mud Marine Disposal Facility at Airport East / East Sha ▇▇▇▇ Area (AEIAR-089/2005), it is assumed that TSHD with ▇▇▇▇▇▇ size of 4,500 m3 would be used.
Scenario C2 is similar except the dredging would be conducted with one TSHD.
To capture this movement, the sediment source for TSHD would be modelled as a moving source along the northern part of the eastern edge of the key area for potential CMP development.
On the other hand, capping using TSHD would involve the delivery of capping materials to the seabed through a pipe, which result in less disturbance and fine loss.