scholarly journals STUDY OF SHORELINE CHANGES AT JENEBERANG RIVER DELTA, MAKASSAR

Author(s):  
Sakka Sakka ◽  
Mulia Purba ◽  
I Wayan Nurjaya ◽  
Hidayat Pawitan ◽  
Vincentius P. Siregar

The study of shoreline changes during 1990 - 2008 in the delta of the River Jeneberang, Makassar was conducted by evaluating sediment transport into and out of a cell. Longshore sediment transport was computed by considering the influence of heights and angles of the breaking waves. Results of calculation of sediment transport showed that the dominant of sediment transport was to the north during the arrival of the southwest and west waves, and to the south when the wave coming from the northwest. Comparison between shore profiles resulting from model and coastline satellite imagery showed similarity. The difference between the two tend to be occurred at the head land part of the shoreline. This was due to complexity of coastal dynamic at the area. The results of the 19 years shoreline simulation showed that there was a tendency of abrasion at the upsteam head land part as the wave energy tend to converge and accretion at the bay part as the wave energy tend to diverge. Abrasion mainly occurred at Tanjung Bunga (head land) where the coast retreat 181.1 m. Accretion occur in the bay area (Tanjung Merdeka) where the coast advance to the sea for about 59.8 m. The shoreline tend to be stable when the profile was straight such as Barombong Coast.Keywords: abrasion, accretion, sediment transport, shoreline changes.

2011 ◽  
Vol 3 (2) ◽  
Author(s):  
Sakka Sakka ◽  
Mulia Purba ◽  
I Wayan Nurjaya ◽  
Hidayat Pawitan ◽  
Vincentius P. Siregar

<p>The study of shoreline changes during 1990 - 2008 in the delta of the River Jeneberang, Makassar was conducted by evaluating sediment transport into and out of a cell. Longshore sediment transport was computed by considering the influence of heights and angles of the breaking waves. Results of calculation of sediment transport showed that the dominant of sediment transport was to the north during the arrival of the southwest and west waves, and to the south when the wave coming from the northwest. Comparison between shore profiles resulting from model and coastline satellite imagery showed similarity. The difference between the two tend to be occurred at the head land part of the shoreline. This was due to complexity of coastal dynamic at the area. The results of the 19 years shoreline simulation showed that there was a tendency of abrasion at the upsteam head land part as the wave energy tend to converge and accretion at the bay part as the wave energy tend to diverge. Abrasion mainly occurred at Tanjung Bunga (head land) where the coast retreat 181.1 m. Accretion occur in the bay area (Tanjung Merdeka) where the coast advance to the sea for about 59.8 m. The shoreline tend to be stable when the profile was straight such as Barombong Coast.</p><p>Keywords: abrasion, accretion, sediment transport, shoreline changes.</p>


2020 ◽  
Vol 8 (8) ◽  
pp. 572
Author(s):  
Jung-Eun Oh ◽  
Yeon S. Chang ◽  
Weon Mu Jeong ◽  
Ki Hyun Kim ◽  
Kyong Ho Ryu

Video monitoring systems (VMS) have been used for beach status observation but are not effective for examining detailed beach processes as they only measure changes to the shoreline and backshore. Here, we extracted longshore sediment transport (LST) from VMS in order to investigate long- and short-term littoral processes on a pocket beach. LST estimated by applying one-line theory, wave power, and the oblique angle of incident waves were used to understand shoreline changes caused by severe winter storms. The estimated LST showed good agreement with the shoreline changes because the sediments were trapped at one end of the pocket beach and the alongshore direction of transported sediments was corresponded to the direction of LST. The results also showed that the beach that was severely eroded during storms was also rapidly recovered following the evolution of LST, which indicates that the LST may play a role in the recovery process while the erosion was mainly caused by the cross-shore transport due to storm waves. After the beach was nourished, beach changes became more active, even under lower wave energy conditions, owing to the equilibrium process. The analysis presented in this study could be applied to study inhomogeneous beach processes at other sites.


2018 ◽  
Vol 9 (2) ◽  
pp. 585-596
Author(s):  
Koko Ondara ◽  
Semeidi Husrin

One of the problems that often occured in the bay area is a sedimentation process that occurred continuously, causing silting. The movement of sediment material in the process of sedimentation is influenced by the movement of the water flow like the tides, winds, currents and waves. The aim of this study was to determine the characteristics of the hydrodynamic conditions, particularly the distribution pattern and the capacity of the sediments in the Kendari Bay with oceanographic modeling approach. Bathymetry data measured at the site of the research conducted in August 2015. The analysis of distribution patterns of sedimentation, sedimentation capacity, wave hindcasting, wind data and tidal data using software, hindcasting results indicate the dominant wind direction coming from the east. Type tides in Kendari Bay is a mixed mainly semiurdunal tides. The concentration of suspended sediment at low tide is greater than at high tide.  Keywords: sediment transport, wave characteristics, Kendari Bay, hydro - dynamics, mike21


2021 ◽  
pp. 187-243
Author(s):  
John M. Armentrout

ABSTRACT This field guide reviews 19 sites providing insight to four Cenozoic deformational phases of the Cascadia forearc basin that onlaps Siletzia, an oceanic basaltic terrane accreted onto the North American plate at 51–49 Ma. The field stops visit disrupted slope facies, prodelta-slope channel complexes, shoreface successions, and highly fossiliferous estuarine sandstones. New detrital zircon U-Pb age calibration of the Cenozoic formations in the Coos Bay area and the Tyee basin at-large, affirm most previous biostratigraphic correlations and support that some of the upper-middle Eocene to Oligocene strata of the Coos Bay stratigraphic record represents what was differentially eroded off the Coast Range crest during ca. 30–25 Ma and younger deformations. This suggests that the strata along Cape Arago are a western “remnant” of the Paleogene Tyee basin. Zircon ages and biostratigraphic data encourages the extension of the Paleogene Coos Bay and Tyee forearc basin westward beyond the Fulmar fault and offshore Pan American and Fulmar wells. Integration of outcrop paleocurrents with anisotropy of magnetic susceptibility data from the middle Eocene Coaledo Formation affirms south-southeast to north-northwest sediment transport in current geographic orientation. Preliminary detrital remanent magnetism data show antipodal directions that are rotated clockwise with respect to the expected Eocene field direction. The data suggest the Eocene paleo-shoreline was relatively north-south similar to the modern shoreline, and that middle Eocene sediment transport was to the west in the area of present-day Coos Bay. A new hypothesis is reviewed that links the geographic isolation of the Coos Bay area from rivers draining the ancestral Cascades arc to the onset of uplift of the southern Oregon Coast Range during the late Oligocene to early Miocene.


1985 ◽  
Vol 1985 (1) ◽  
pp. 359-365 ◽  
Author(s):  
Edward H. Owens

ABSTRACT Mechanical dispersion by waves is usually considered to be the primary factor that controls the persistence of spilled oil reaching the coast. This assumption is accurate for stable coasts that are not subject to net erosion or accretion and beaches where oil would not be buried by onshore, offshore, or alongshore movement of sediments. On high energy coasts, oil can be rapidly buried or eroded, depending on the stage of beach changes. Similarly, oil stranded on coasts subject to rapid net accretion or erosion is likely to be buried or dispersed. Rapid shoreline changes can occur in areas of low wave energy, so wave energy levels cannot be used alone as an indicator of oil persistence. Sections of the North American Beaufort Sea coast are undergoing net long term changes on the order of 10 meters per year, despite the short (3 month) open water season and the small fetch areas. Beach migration or cliff retreat on these low energy coasts often has a net rate on the order of one meter per month. In these situations, the changes in shoreline location due to sediment erosion and transport reflect the integrated effect of coastal processes and the materials on which the processes act. Rates of shoreline changes can be used as an indicator to estimate the residence time of stranded oil, irrespective of the shoreline character or the wave energy levels at the shoreline. Wave energy levels alone are an inadequate basis for estimating the residence time of stranded oil.


2007 ◽  
Vol 44 (5) ◽  
pp. 643-664 ◽  
Author(s):  
Kenneth L Buchan ◽  
Jean Goutier ◽  
Michael A Hamilton ◽  
Richard E Ernst ◽  
William A Matthews

An extensive set of north- to northwest-trending diabase dykes, termed the Lac Esprit swarm, is identified in the Superior Province east of James Bay based on geological mapping and a distinctive paleomagnetic pole (61.7°N, 169.1°E, dm = 7.7°, dp = 5.5°). The Lac Esprit swarm yields a U–Pb baddeleyite age of 2069 ± 1 Ma similar to that of the 2076+5–4 Ma Fort Frances swarm of the western Superior Province. Their paleomagnetic declinations differ by 23° ± 12° after correction to a common reference locality. The difference is likely due mainly to counterclockwise rotation about a vertical axis of the Fort Frances area relative to the Lac Esprit area. Differential rotation of 10°–20° has been proposed more locally across the Kapuskasing Structural Zone separating the eastern and western Superior Province in earlier paleomagnetic studies of ca. 2450 Ma Matachewan and 2170 Ma Biscotasing dyke swarms. Thus, relative rotation may have involved the entire eastern and western Superior Province, perhaps in response to collisional events associated with the Trans-Hudson Orogen to the north or the Penokean orogen to the south, or in response to rifting beneath Hudson Bay. Other dykes in the study area are interpreted from a combination of paleomagnetism, trend, and geochemistry to belong to the Senneterre, Matachewan, and Mistassini swarms. The 2216 Ma Senneterre dykes form part of a giant swarm that fans across the eastern Superior Province. Paleomagnetic directions and geometry of this swarm rule out substantial block rotations within the eastern Superior Province since dyke emplacement.


1982 ◽  
Vol 1 (18) ◽  
pp. 81
Author(s):  
Yoshito Tsuchiya

The main purpose of this paper is to propose an ideal methodology for beach erosion control from the viewpoint of controlling the total rate of longshore sediment transport. For this, a new formulation of the rate of longshore sediment transport is made. The total rate is directly proportional to the longshore component of wave power in field coasts, but not in laboratory ones. How to control the total rate of longshore sediment transport is considered. There are two ways applicable for practical purposes. The first is to decrease the breaker depth by changing the bottom topography, and the second to decrease the incident angle of breaking waves by changing either the bottom topography or the inclination of shoreline to the incidence of predominant waves. Two typical, but ideal examples are explained for beach erosion control by this methodology.


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