Impacts of jetty construction on the wave heights off the Kiashahr lagoon

Abstract

Coastal managers and ecologists are confronted with tasks to estimate wave heights in the Kiashahr sea area, since hydrodynamic factors can profoundly impact this environment. In this study, wind data and an empirical wind wave predicting model were used to estimate deepwater wave characteristics in the Kiashahr sea area; while a numerical model was used to determine wave characteristics in shallow waters. Wave heights were also determined and compared at different stations before and after construction of 2 jetties at the lagoon mouth to evaluate their efficiency in wave height reduction. Results revealed that wave height is in the range of 0.8 to 1.2 m at Sefid Rud river mouth. Significant wave height reduction in the range of 0.15 to 1.2 m occurred at the entrance of the lagoon due to construction of the jetties. This attenuation of wave energy may result in some impacts on the ecosystem health of Kiashahr lagoon such as increased sedimentation, reduction in flushing rates, dumping of garbage and consequently, more pollution.

Impact of Jetty Configuration Changes on the Hydrodynamics of the Subtropical Patos Lagoon Estuary, Brazil

“…As a consequence, changes in the transport and distribution of the estuarine properties and organisms in the whole lagoon could also be expected. In [10], the authors explained that changes in the circulation pattern could also negatively impact the navigation of large vessels and the pollution and sedimentation processes (by the reduction of the ebb currents and natural dredging in the access channel). Other effects, such as the migration of the tidal delta as a result of changes in the morphodynamics of the central channel and the infilling or formation of banks on the jetty sides, which could influence the maintenance of adequate water depth, were mentioned by [2] after the Ribadeo port expansion in Spain.…”

“…Jetty construction can change the direction of the tidally induced currents, influence the evolution of the bed level, and induce sedimentation and erosion [9]. It can also reduce the wave height and flushing rates and increase sedimentation and pollution [10]. It has also been reported that the extension of jetties does not change inlet flow propagation and water quality, although changes in the topography increase current velocities and salinity values [11].…”

Intertidal intercepted sediment at jetties along the Gulf of Thailand

“…In Europe, Z ̌ilinskas et al (2020) showed that a sediment accretion occurred in a nearshore zone after completing a jetty. In Iran, Azarmsa et al (2009) evidently showed the increased sedimentation, reduction in significant wave height, and flushing rate after a jetty construction at the Kiashahr lagoon. Anh et al (2021) investigated the erosion-deposition process along a jetty in Vietnam and found that there was 56,442 m 3 of deposited sediment during the northeast monsoon, which was ten times higher than the amount occurring in the southwest monsoon.…”