Author(s): Ahmad Hadi Mohamed Rashidi, Mohamad Hidayat Jamal, Mohd Radzi Abd Hamid, Siti Salihah Mohd Sendek
Linked Author(s): Ahmad Hadi Mohamed Rashidi
Keywords: Shore protection, coastal hydraulic, physical model, beach erosion, natural beach accretion
Abstract: NEXC Block is an innovative shore protection structure which is designed to protect the coast from severe erosion during monsoon season. While on a calmer period, the system encourages sediment accumulation thus expands the beach naturally. NEXC Block is placed within Mean Higher High Water and Highest Astronomical Tide water level with sufficient toe protection for stability and efficiency, ensuring minimum adverse impact to existing coastal hydrodynamic. This paper aims to present the development process of NEXC Block in 2-D wave flume facility, where site measurement works are conducted for data validation and monitoring. Model dimension and hydrodynamic parameters are geometrically downscaled to 1: 20. Two slope gradient values are used representing actual beach profiles at selected sites. Cohesive-form sediment size is 100�m. Three water levels; Mean Lower Low Water, Mean Sea Level and Mean Higher High Water with two significant wave height values Hs (irregular waves) are used for experiments. Beach profile is measured both before and after each experiment for erosion-accretion and stability analysis. Experiments on exposed beach without structure are also carried out as reference profile. The experiments show that NEXC Block model structure installed with ample toe protection is a fairly stable coastal protection structure. The structure is able to withstand strong wave impact during monsoon where no significant structural movement was detected. However scouring is prevalent at the toe of structure at unprotected structures. Some parts of NEXC Block and toe protection are exposed during monsoon season but less sediment are found eroded as compared to exposed unprotected beach in maintaining beach stability. Moreover during a longer calm period, the sediments are found to return back to the beach hence nourishing and expanding the beach naturally
Year: 2017