Harbor Basin Research Articles

Numerical Analysis of the Impact of Harbor Basin Excavation of High-Piled Beam Plate Wharf

Numerical Analysis of the Impact of Harbor Basin Excavation of High-Piled Beam Plate Wharf

Investigating the Harbour Basin Tranquillity in the Genaveh Port Development Plan

Abstract The Genaveh commercial port was placed on the agenda of the Iranian PMO (ports and maritime organization) to consider economic, commercial and residential development in Bushehr province and specifically in Genaveh city. In order to increase the water capacity of the port, it is necessary to build a new harbour basin for exploitation and commercial purposes at a depth of 5 to 6 meters by extending the existing jetties arms in front of the port. This research aims to investigate the harbour basin’s tranquillity for providing vessels with safe berthing. For this purpose, three modules, namely the flow model (FM), spectral wave (SW) and Boussinesq waves model (BW) from the MIKE 21 software package, were utilized. According to the monitoring data, which is provided by the Iranian PMO, the harbour basin’s tranquillity based on the prevailing wave directions was investigated. Based on the diffraction graph in the harbour basin, the results showed that, according to the percentage of permissible diffraction recommended by different valid regulations, there is a need to modify the geometry of the breakwater arms to increase the harbour basin’s tranquillity at the port in the development plan.

Environmentally Friendly Vertical Wall Breakwater with Culvert for Encircled Harbor Basin

AbstractVertical wall breakwater with culvert (VWBC) is an environmentally friendly way proposed for the encircled harbor basin, which can break waves and allow the current to pass through. This pa...

U–Pb detrital zircon constraints on active margin magmatism and sedimentation after the Grampian Orogeny in western Ireland

Early Ordovician collision of the Lough Nafooey Arc (part of the Baie Verte Oceanic Tract) with the passive continental margin of Laurentia peaked at c. 475 Ma in Scotland and Ireland and was followed by subduction polarity reversal. We examined Upper Ordovician–Silurian sedimentary rocks from western Ireland to see whether collision was followed by renewed arc magmatism. Despite the scarcity of dated igneous intrusions between the Grampian ( c. 470 Ma) and Acadian ( c. 420 Ma) orogenies in Ireland, detrital zircons show a continuity of activity peaking at 480–440 Ma, implying no hiatus in regional magmatism. Differences in zircon U–Pb age spectra highlight the isolation of basins in the southern Killary Harbour area from those north of the South Mayo Trough. These latter rocks were largely derived by erosion from Moine and Upper Dalradian sources. By contrast, the Killary Harbour Basin shows a decreasing influence from the Dalradian after c. 436 Ma and an increasing influence of contemporaneous magmatic zircons. These were transported from sources along-strike from the present NE, probably at the southern end of the Scandian Mountains in SE Greenland. The western Irish basins formed as pull-apart basins in a forearc setting and are analogous to Cenozoic pull-apart basins in Sumatra. Supplementary material: U-Pb zircon analytical data is available at a decreasing influence from the Dalradian after c. 436 Ma and an increasing influence of contemporaneous https://doi.org/10.6084/m9.figshare.c.5209849

Numeric Simulation of Suspended Sediment Transportation during Dredging of Harbor Basin

Huang, Y.; Sheng, Y.H.; Min, X.Q.; He, Y.F., and Chen, P., 2020. Numeric simulation of suspended sediment transportation during dredging of harbor basin. In: Guido Aldana, P.A. and Kantamaneni, K. (eds.), Advances in Water Resources, Coastal Management, and Marine Science Technology. Journal of Coastal Research, Special Issue No. 104, pp. 276–280. Coconut Creek (Florida), ISSN 0749-0208.Maintaining the safe water depth of the harbor basin is important to ensure the safety of ships, while dredging is the major method to accomplish this task. However, the dispersion and transportation of suspended sediment during the degrading process, may change the seawater quality. This research utilizes the 2D tidal flow model and 2D sediment numerical model to simulate the distribution of suspended sediment during dredging, and then analyzes the influence on the nearby sea area. The major conclusions can be summarized as follows: (1) the equivalent roughness method can simulate well in the research area; (2) the dredging in Xiazhi Harbor basin has limited influence on the seawater quality. When the increased Suspended Sediment Concentration (SSC) reaches 10 mg/L, the impact distances of both flood current and ebb current are 1.66 km and 0.99 km, respectively; (3) since the tidal dynamic is stronger at the ebb current, the suspended sediment diffusion at this period is more significant, and has less impact on the water quality. Thus, it is recommended to dredge the harbor basin during ebb current.

Preliminary Investigation of Microlitter Pollution in Low-Energy Hydrodynamic Basins Using Sabella spallanzanii (Polychaeta: Sabellidae) Tubes.

Harbor basins are strategically important and heavily impacted water bodies according to the water framework directive. Due to constant traffic, variety of activities, and low-energy hydrodynamics, these areas can have high degrees of water pollution. This study reports the results of the preliminary investigation of anthropogenic microlitter (AM) pollution in a semi-enclosed basin (Civitavecchia harbor; northern Tyrrhenian Sea, Italy) using the tubes built by the polychaete Sabella spallanzanii. The visual inspection showed AM particles within the tube structure as a result of its building process. The total average AM abundance was 20.8 ± 3.7 AM g-1. AM abundances and flushing time as the hydrodynamic parameter of water renewal highlight the homogeneity of the sampling area. The suitability of S. spallanzanii tubes as a potential tool to investigate the AM pollution level in sheltered and polluted environments is highlighted.

Transient reflection from mud during molecular diffusion of salt

Harbor basins and estuarine environments experience drastic salinity fluctuations in the water near the water-sediment interface, which can significantly affect how sound interacts with a low-velocity mud bottom. This presents challenges in applications including mine detection, port protection and shallow water sonar. In a previous investigation of this system, a mud sample that was saturated with fresh water was instantaneously exposed to salt water. Laboratory measurements of plane wave reflection from the water-mud interface were obtained using a time-gated broadband impulse as time evolved. Results suggested molecular diffusion of salt into the sample had altered the reflected pulse’s amplitude and caused a depth-dependent impedance profile in the mud. The sediment was discretized into layers much thinner than a wavelength and a multi-layer steady-state model was used to predict the reflection from the diffusing mud. As the effective diffusion length reached a critical value, predictions of the steady-state model began to deviate from the measurements, indicating that a transient solution was required. A model of the transient reflection of a finite-length pulse from a half space with an arbitrary impedance will be presented and model results compared with laboratory measurements. [Work supported by ONR.]

Laboratory measurements of a phase shift in the reflection from a water-mud interface due to water column variability

Harbor basins and certain continental shelf environments experience significant variability due to tides, surface heating, currents, and other oceanographic processes. Dynamic processes such as these can cause substantial sound speed and density fluctuations in the water column over short time periods, which are often unknown to sonar users. Such variations are not critical over high-velocity bottoms such as sand, but can produce significant changes in how sound interacts with low-velocity fine-grained sediments. High levels of variability and a low-velocity bottom, such as mud, can therefore present challenges in applications including mine detection, port protection and shallow water sonar. At certain penetration angles, temporal variations in the water-to-sediment sound speed ratio can cause 180 degree phase shifts in the reflected field, which in turn produces waveguide propagation and target scattering field variability. To begin to understand these processes, laboratory measurements of plane wave reflection were obtained from a water-mud interface while varying salinity and temperature of the water. Results indicate that the dynamic nature of sound speed ratio at the ocean bottom can cause significant effects in shallow water environments with muddy bottoms. [Work supported by ONR.]

Accommodation space controls on incised-valley sediment accumulation rates during the Holocene marine transgression (0–11 ka) in Grays Harbor, a large meso-tidal estuary, Washington, USA

Holocene deposits (0–11ka) that were drill cored (275 samples from 17 sites) in the meso-tidal Grays Harbor estuary were analyzed for 1) sediment texture and source components and 2) calibrated radiocarbon age. These data were used with basin 10m-contour interval volumes to establish relations between rates of increasing basin accommodation space and sediment volume accumulation. Rates of increasing accommodation space (0.3–2.1×106m3yr−1) are based on interval volumes and a sea level curve (0–11.5ka) for the Grays Harbor basin. Total sediment accumulation rates (0.41–1.4×106m3yr−1) are computed for the same 10m-depth intervals (0–60m depth MSL) and corresponding 10m-interval sedimentation durations (0.7–5.0×103ka) from a sediment level curve. The rates of basin increasing accommodation space and total sediment accumulation are positively correlated (R2=0.81), but sediment accumulation lagged behind increasing accommodation space (23–37%) during early- and middle-Holocene time (7–10ka). Slowing rates of sea level rise after 8ka, permitted combined river and littoral inputs of sediment to reduce basin subtidal water depths (~10m) to intertidal water depths (~1m). The ratios between sand and mud components in the analyzed Holocene deposits are negatively correlated to basin water depth. Shallowing tidal flats promoted the export of river mud out of the estuary and the import of littoral sand into the central estuary areas. Variable rates of increasing basin accommodation space 1) directly controlled the total sediment accumulation rate in the evolving basin and 2) indirectly controlled the relative proportions of mud and littoral sand accumulation, due to changing water depths in the basin. The late-Holocene accumulation of littoral sand (52% of total sediment volume) is used to compute the net littoral sand sink (~100×106m3) in the Grays Harbor basin from a potential 1.0m rise of future sea level following predicted global warming. The contribution of littoral sand from adjacent barrier sand spits (20km in length) to fill the increasing accommodation space in the Grays Harbor estuary could result in 0.5–1.0km of shoreline retreat following a 1.0m rise in sea level.

Assessment of Microbiological and Bio-chemical Quality of Fish in a Supply Chain in Negombo, Sri Lanka

This study aimed to investigate quality of fish landed in Negombo area and distributed in suburban areas in Western province of Sri Lanka. Hundred samples of large fish (Katsuwonus pelamis and Euthynnus affinis) and 60 samples of small fish (Amblygaster sirm, Pterocaesio chrysozona, Stolephorus commersoni, and Sardinella albella) were sampled from different stages of a supply chain at five and six sampling visits, respectively. All fish samples (N=160) were analysed for aerobic plate counts (APC) at 37oC, Coliforms, feacal coliforms, Escherichia coli, Salmonella spp., Listeria monocytogenes, total volatile base nitrogen (TVB-N) while 130 were analysed for histamine. Water from fishery harbor basin, fishery harbour, ice manufcaturing plants and ice used in multiday boats were also analysed for microbiological parameters. Large and small fish contained APC in the range of 2.0 x102 - 2.0 x 106 and 8.0×103 - 2.0×108 cfu/g, respectively. Faecal coliform counts ranged between not detected (ND) and 90 MPN/g in large fish and between ND and >1100 MPN/g in small fish. 5% of large fish were contaminated with E.coli and ranged from ND to 15 MPN/g. E.coli was present in 70% of small fish samples and ranged from ND to >1100 MPN/g. Of the 160 fish samples, tested Salmonella spp were detected in nine occassions. Of the 160 fish samples, L. monocytogenes was found in eight Katsuwonus pelamis and one Sardinella albella fish. TVB-N of large fish were found at range of 1-67 mgN/100g and 79% samples contained unaccptable levels. Small fish contained about 25.10-104.30 mgN/100g while 78% samples exceeded acceptable levels. Histamine level of large and small fish, 26% and 83% of samples exceeded the maximum acceptable levels, respectively. Harbour basin water was heavily contaminated with Salmonella spp. (50%), Faecal streptococci (100%), Faecal coliforms and E.coli (100%). Ice samples (20%) from one ice plant were found contaminated with Salmonella spp.

Experimental and Numerical Study of 3D Hydrodynamic Characteristics in an Excavated Harbor Basin

As a kind of common port layout forms, excavated harbor basin was widely applied with its many advantages. But the sediment transport processes and water motion in such harbor are complex and of obvious three-dimensional characteristics affected by a lot of factors. To investigate the 3D hydrodynamic characteristics in an excavated harbor basin, experimental research based on PIV technology and numerical study through a 3D code with DES turbulence model has been developed respectively. The 3D hydrodynamic and sediment deposition characteristics in the harbor have been indicated successfully in this paper.

The Design of Mechanical System for Harbor Basin Wave Maker

The design of mechanical system for harbor basin wave maker is introduced in this article. The installation form of wave maker is ground to pin type. The push-wave plate is driven by the AC servo motor and ball screw. The parameters of ball screw and the selection of servo motor are determined by calculating, and then check the bearing capacity of servo motor. The performance test has verified that the design of wave-maker system can meet the requirements.

On harbour siltation in the fresh-salt water mixing region

In this paper a novel series of field measurements are presented, which are the first to elucidate the processes influencing siltation in Botlek Harbour. Botlek Harbour is situated at the limit of saline water intrusion in the Rotterdam Waterway. Normally, after the ebb tide fresher river waters are found in the Rotterdam Waterway at the location of Botlek Harbour. On the flooding tide, the tip of the salt wedge is advected along the Rotterdam Waterway towards the mouth of Botlek Harbour. Hence on flood, a lock-exchange mechanism operates between Botlek Harbour and the Rotterdam Waterway. On the flood tide, when there is a supply of suspended particulate matter (SPM) associated with the presence of the estuarine turbidity maximum (ETM) at the mouth of the harbour, the survey data show exchange of SPM into the harbour. This lock-exchange process is found to be the dominant cause for SPM transport into the harbour. This is further substantiated by an analysis of the mass transport mechanisms. In this analysis, the vertical profiles of the instantaneous velocity, salinity and SPM concentration fields, recorded during the surveys, were decomposed into advective and dispersive transport components. The results of this analysis indicate that the correlation between the lock-exchange mechanism on the flood tide with the availability of SPM for exchange and efficient trapping, dominate the total exchange of SPM (97%). Hence, the increase in measured near-bed SPM concentration within the harbour is ascribed to tidal advection of saline water and the ETM along the Rotterdam Waterway. Tidal advection controls the density difference between the estuary and harbour, as well as the availability of SPM for exchange at the entrance to Botlek Harbour. The location of the ETM at the tip of the salt wedge is a key factor in supplying SPM to Botlek Harbour. Consequently the timing of the availability of SPM at the mouth of the harbour needs to be considered in siltation studies. The survey data suggest that Botlek Harbour basin has a 100% trapping efficiency. Analysis of 5 months of data, from a measuring rig located within the harbour, show excursions of the limit of the salt wedge and ETM. These excursions are likely to affect siltation of upstream harbours. Salinity-induced density gradients control the transport and subsequent trapping of SPM in the estuary in close proximity to the harbour entrance, the exchange of SPM between the estuary and harbour, and the trapping of SPM in the harbour basin.

津波来襲時の港内係留船の船体運動の違いについて

津波来襲時の港内係留船の船体運動の違いについて

Historical and ecological analysis of coral communities in Castle Harbour (Bermuda) after more than a century of environmental perturbation

The coral reefs in Bermuda’s Castle Harbour basin have been subjected to varying anthropogenic stressors for over 100 years. These include restriction of water flow through the construction of a causeway in the late 19th century and an extensive dredging and land reclamation operation during World War II. In the 1970s, disposal of bulk waste commenced at a foreshore reclamation site in Castle Harbour. Since 1996 the waste stream has included blocks of cement-stabilized municipal incinerator ash. This study provides a historical and quantitative ecological review of the Castle Habour reef ecosystem as a case study, assessing the responses of the reef to more than a century of anthropogenic disturbance. Measures of the coral community, flow rates, turbidity and sedimentary regimes suggest the present structure of the coral community largely reflects the impacts of the historic dredge and fill operations prior to the establishment of the foreshore dump site. Recent increases in the abundance of some sediment tolerant, massive reef-building coral species ( Diploria strigosa and Montastraea cavernosa) suggest adaptation to chronic sediment stress.

Effects of extreme tidal range on characteristics of polychlorinated biphenyl distribution in sediment of industrial Incheon North Harbor, Korea

This study investigated the influence of the high tidal range on the polychlorinated biphenyl (PCB) levels and the compositional characteristics in the sediments of the North Incheon Harbor basin, Korea. The results indicated that the high tidal range could induce complicated effects on the distribution and the compositional characteristics of PCBs. Significant differences in the total PCB concentration were found between the tidal and subtidal zones. Higher total PCBs in the tidal zone established a total PCB gradient in a transversal direction along the harbor basin. The large tidal range created tidal currents strong enough to grade the sediment particles, establishing a gradient of total PCBs corresponding to an observed sediment particle size along the longitudinal direction of the basin. Heterogeneous congener patterns were observed in some parts of the tidal zone where diverse physicochemical and microbiological conditions are to be expected. However, tidally driven, active sediment transport promoted spatial homogeneity in the congener pattern. Sedimentation rate of suspended solids appeared to overwhelm any induced heterogeneity in the PCB congener pattern. Consequently, the congener pattern within the harbor basin was fairly uniform and similar to that of a dominant input source.

Water Balance, Climate Change and Land-use Planning in the Pearl Harbor Basin, Hawai'i

The Pearl Harbor basin on the tropical oceanic island of O'ahu, Hawaii, exhibits extreme climatic gradients, rapid land-use change and groundwater use near sustainable yield. The basin's water usage and groundwater recharge, and hence water yield, are strongly influenced by the spatial distribution of land use. Current recharge is expected to drop by about one-eighth with the demise of the remaining sugar-cane and pineapple. Evidence suggests that lower rainfall and increased evaporation may well accompany warmer periods in Hawaii, and water-balance simulations indicate many scenarios having a significant decrease in available water. Land-use planners can use such results in tandem with multiobjective optimization models to generate alternative land-use plans and show trade-offs among objectives.

Uncertainty in recharge estimation: impact on groundwater vulnerability assessments for the Pearl Harbor Basin, O'ahu, Hawai'i, U.S.A.

In this paper, uncertainty in recharge estimates is investigated relative to its impact on assessments of groundwater contamination vulnerability using a relatively simple pesticide mobility index, attenuation factor (AF). We employ a combination of first-order uncertainty analysis (FOUA) and sensitivity analysis to investigate recharge uncertainties for agricultural land on the island of O'ahu, Hawai'i, that is currently, or has been in the past, under sugarcane or pineapple cultivation. Uncertainty in recharge due to recharge component uncertainties is 49% of the mean for sugarcane and 58% of the mean for pineapple. The components contributing the largest amounts of uncertainty to the recharge estimate are irrigation in the case of sugarcane and precipitation in the case of pineapple. For a suite of pesticides formerly or currently used in the region, the contribution to AF uncertainty of recharge uncertainty was compared with the contributions of other AF components: retardation factor (RF), a measure of the effects of sorption; soil-water content at field capacity (ΘFC); and pesticide half-life (t1/2). Depending upon the pesticide, the contribution of recharge to uncertainty ranks second or third among the four AF components tested.The natural temporal variability of recharge is another source of uncertainty in AF, because the index is calculated using the time-averaged recharge rate. Relative to the mean, recharge variability is 10%, 44%, and 176% for the annual, monthly, and daily time scales, respectively, under sugarcane, and 31%, 112%, and 344%, respectively, under pineapple. In general, uncertainty in AF associated with temporal variability in recharge at all time scales exceeds AF. For chemicals such as atrazine or diuron under sugarcane, and atrazine or bromacil under pineapple, the range of AF uncertainty due to temporal variability in recharge encompasses significantly higher levels of leaching potential at some locations than that indicated by the AF estimate.

Uncertainty of Groundwater Vulnerability Assessments for Agricultural Regions in Hawaii: Review

AbstractThere are important challenges associated with assessing potential groundwater vulnerability hazards that may result from regional scale applications of agrochemicals. The increasing availability of Geographic Information System (GIS) software to those involved in assisting with landuse decisions has resulted in the widespread production of multicolored risk management maps for many environmentally sensitive issues. Soil‐based GIS's have recently been coupled to various solute‐leaching models to make near‐surface groundwater vulnerability assessments for guidance in pesticide regulation in several states. In general, these assessments rest on soil, climatic, and chemical data that are extremely sparse and contain considerable uncertainty. It is also important to acknowledge the uncertainty associated with the transport/fate processes that are not accounted for by the modeling approach used to make the assessment. In this paper, we review the results from a series of papers that have focused on characterization of uncertainty in pesticide mobility estimates, using the attenuation and retardation indices (AF and RF), for the Pearl Harbor Basin on the Hawaiian island of Oahu. Relative to data error uncertainties, we discuss the impacts of: (i) soil, climatic, and chemical data base uncertainties, (ii) reductions in data base uncertainties, (iii) extrapolation of soil data base information based on soil taxonomy and soil survey, and (iv) importing information from outside the region of interest. Relative to model error uncertainties, we compare pesticide leaching estimates from the simple AF and RF mobility indices with simulations from the EPA's Pesticide Root Zone Model (PRZM) and field observations. Finally, we outline a Regional Integrated Risk Assessment approach for characterizing regional scale groundwater vulnerability for near‐surface nonpoint sources.“Hey farmer farmer put away that DDT” Joni Mitchell, “Big Yellow Taxi”

Chemical Leaching Near the Waiawa Shaft, Oahu, Hawaii: 2. Modeling Results

AbstractThis paper is the second part of a two‐part series concerned with assessing the potential for organic chemical leaching to a ground‐water skimming tunnel in the Pearl Harbor Basin, Oahu, Hawaii, as a direct result of proposed urban development. The Pesticide Root Zone Model (PRZM) was used, after testing with field and laboratory data described in the companion paper, to make long‐term predictions of the movement of chlorpyrifos, diazinon, metribuzin, and nitrate under various recharge scenarios. The PRZM simulations revealed that, with the exception of chlorpyrifos, detectable levels of all the chemicals considered in this study may leach through the unsaturated zone to the water table from where they may eventually migrate to the skimming tunnel. The simulated concentrations in leachate reaching the water table were sufficiently low, considering subsequent mixing in the ground water, to suggest no adverse health effects. The reliability of the simulated results are laced with enough uncertainty, however, to suggest the need for monitoring for diazinon, metribuzin, and nitrate, if development does proceed. The methodology presented in this series is a first attempt at establishing a protocol for using numerical modeling, supported by field and laboratory measurements to aid in land‐use change consideration in Hawaii when nonpoint ground‐water contamination from organic chemicals is of concern.