Mean Water Level Research Articles

Flood meadows in Finland – their development during the past century

Flood meadows represent semi‐natural vegetation by the great rivers in northern Finland. Physical forces acting on the river banks such as ice, floods and annual sedimentation create temporarily oxygen‐free conditions as well as open space for the growth of grasses and herbs. Besides flood dynamics, clearing and mowing for winter forage maintained flood meadow series representative for centuries. When the regular management for winter forage ceased by the end of 1950's, flood meadows started to overgrow by trees and shrubs, and thus change back to their virgin state.Different meadow types are traditionally arranged into a grassland continuum on the basis of their soil moisture gradient: from dry to wet meadows, from which dozens of vicariating associations emerge. Fine‐featured vegetation types may be categorized into six functional groups according to their vicinity to riverside and flooding frequency.The aim of this study was to define the state of flood meadows in Finland by studying the data collected during the nationwide inventory (NWI) of traditional rural biotopes in Finland 1992–2001, and by comparing NWI with the vast material collected by 14 different researchers starting from the beginning of the 1900's and reaching into first decade of present millennia. First, the NWI and the researchers’ data were studied alone and thereafter the material was pooled and compared.Results show that management cessation have had only minor effect on wet flood meadows close to mean water level. Equisetum fluviatile‐, tall Carex‐ and moist grass flood meadows remain largely open without human influence. However, combined effect of ceased mowing and decreased sedimentation due, e.g. to watercourse regulation and hydraulic engineering, changes also the wet types into open‐ and shrub‐covered swamps. In contrast, without management the uppermost tall herb‐, moist grass‐ and small herb flood meadows turn quickly into thickets. As a consequence, today moist grass‐, tall‐ and small herb flood meadows are critically endangered habitat types in Finland.

Temporal and spatial variability of tidal‐fluvial dynamics in the St. Lawrence fluvial estuary: An application of nonstationary tidal harmonic analysis

AbstractPredicting tides in upstream reaches of rivers is a challenge, because tides are highly nonlinear and nonstationary, and accurate short‐time predictions of river flow are hard to obtain. In the St. Lawrence fluvial estuary, tide forecasts are produced using a one‐dimensional model (ONE‐D), forced downstream with harmonic constituents, and upstream with daily discharges using 30 day flow forecasts from Lake Ontario and the Ottawa River. Although this operational forecast system serves its purpose of predicting water levels, information about nonstationary tidal‐fluvial processes that can be gained from it is limited, particularly the temporal changes in mean water level and tidal properties (i.e., constituent amplitudes and phases), which are function of river flow and ocean tidal range. In this paper, a harmonic model adapted to nonstationary tides, NS_TIDE, was applied to the St. Lawrence fluvial estuary, where the time‐varying external forcing is directly built into the tidal basis functions. Model coefficients from 13 analysis stations were spatially interpolated to allow tide predictions at arbitrary locations as well as to provide insights into the spatiotemporal evolution of tides. Model hindcasts showed substantial improvements compared to classical harmonic analyses at upstream stations. The model was further validated by comparison with ONE‐D predictions at a total of 32 stations. The slightly lower accuracy obtained with NS_TIDE is compensated by model simplicity, efficiency, and capacity to represent stage and tidal variations in a very compact way and thus represents a new means for understanding tidal rivers.

Modeling of Time-Varying Shear Current Field Under Breaking and Broken Waves with Surface Rollers

This study aims to develop a new numerical model for predictions of the time-varying shear current field under breaking and broken waves. The present model differs from the other similar existing models in that the model explicitly determines the bottom shear stress so that it satisfies both force balance and mass-conservation equations while most of the other existing models leave the bottom shear stress as one of the calibration parameters to be fitted. The present model consists of two sub-models, a wave model and a flow model. The wave model is based on modified Boussinesq equations with evolution and dissipation of surface rollers. The flow model is based on Reynolds' equations with turbulence closure models and computes vertical profiles of wave-induced shear current field. The numerical model is applied to various existing and newly performed experimental cases which cover various breaker types and bed profiles with different bed roughness. The present model showed overall good predictive skills of various surf zone hydrodynamics such as wave heights, mean water levels and undertow profiles. It should also be highlighted that the model has only a few calibration parameters and the predictive skill of the model is relatively less sensitive to these parameters.

Navy Nearshore Ocean Prediction Systems

Abstract : Knowledge of the nearshore ocean environment is important for naval operations, including military and humanitarian applications. The models used by the US Navy for predicting waves and circulation in the coastal regions are presented here. The wave model of choice for coastal regions is the Simulating WAves Nearshore (SWAN) model, which predicts wave energy as a function of frequency and direction. SWAN is forced by winds as well as waves at the offshore boundaries. For coastal circulation, Delft3D, composed of a number of different modules that can be coupled with each other, is presently used. Most applications for daily operational predictions use only the Delft3D-FLOW module, which predicts currents, mean water levels, temperature, and salinity. Inputs to the model include winds, tides, general ocean circulation, waves, daily river discharges, temperature, and salinity. Delft3D-FLOW is coupled with the Delft3D-WAVE module for areas where wave effects are of importance. A four-dimensional variational assimilation (4DVar) system based on SWAN, the SWANFAR system, is under development for nearshore wave predictions. It will improve wave predictions by using regional wave observations. We present several case studies that illustrate the validation and diverse applications of these models. All operational systems are run at the Naval Oceanographic Office.

Large-scale regionalization of water table depth in peatlands optimized for greenhouse gas emission upscaling

Abstract. Fluxes of the three main greenhouse gases (GHG) CO2, CH4 and N2O from peat and other soils with high organic carbon contents are strongly controlled by water table depth. Information about the spatial distribution of water level is thus a crucial input parameter when upscaling GHG emissions to large scales. Here, we investigate the potential of statistical modeling for the regionalization of water levels in organic soils when data covers only a small fraction of the peatlands of the final map. Our study area is Germany. Phreatic water level data from 53 peatlands in Germany were compiled in a new data set comprising 1094 dip wells and 7155 years of data. For each dip well, numerous possible predictor variables were determined using nationally available data sources, which included information about land cover, ditch network, protected areas, topography, peatland characteristics and climatic boundary conditions. We applied boosted regression trees to identify dependencies between predictor variables and dip-well-specific long-term annual mean water level (WL) as well as a transformed form (WLt). The latter was obtained by assuming a hypothetical GHG transfer function and is linearly related to GHG emissions. Our results demonstrate that model calibration on WLt is superior. It increases the explained variance of the water level in the sensitive range for GHG emissions and avoids model bias in subsequent GHG upscaling. The final model explained 45% of WLt variance and was built on nine predictor variables that are based on information about land cover, peatland characteristics, drainage network, topography and climatic boundary conditions. Their individual effects on WLt and the observed parameter interactions provide insight into natural and anthropogenic boundary conditions that control water levels in organic soils. Our study also demonstrates that a large fraction of the observed WLt variance cannot be explained by nationally available predictor variables and that predictors with stronger WLt indication, relying, for example, on detailed water management maps and remote sensing products, are needed to substantially improve model predictive performance.

Physical and numerical modelling of the Severn Barrage

The Severn Estuary has one of the largest tidal ranges in the world and has long been the subject of consideration for tidal energy generation. Whilst plans to build a tidal barrage across the estuary have existed in various forms since the 1920s, the 1989 Severn Tidal Power Group (STPG) proposal is commonly referred to as the original Severn Barrage. The UK government abandoned this ebb generation scheme as a public investment project in 2010. However, plans to build a two-way generation scheme were more recently put forward by a private consortium, namely Hafren Power. To assess the impact that a barrage would have on the hydro-environment in the estuary a number of numerical modelling studies have previously been conducted for the STPG scheme. As this design has now been superseded by the Hafren Power proposal, new studies have been conducted to investigate the impact of a two-way scheme. In this study the hydro-environmental impacts of both ebb-only and two-way schemes were assessed using physical and numerical modelling techniques. Scale model barrages were constructed and testing was carried out using a physical model of the Severn Estuary, located in the hydraulics laboratory at Cardiff University. A depth integrated numerical model, namely DIVAST, was applied to the physical model geometry and modifications were made to simulate the effects of the barrage structures. The numerical model predictions showed good agreement with the corresponding laboratory data. The results were consistent with conclusions from previous studies, relating to the ebb-only scheme. These included an increase in the minimum water levels upstream of the barrage, a reduction in the mean water levels downstream of the barrage and a general reduction in tidal velocities. For a two-way scheme changes in the tidal elevations and velocities depended on the exact operating conditions of the barrage. It was found that with no starting head the tidal regime was similar to the natural state, with little change in the elevations and a slight reduction in the mean velocities. As a starting head was introduced there was still little change in elevations downstream of the barrage, however, there was an increase in the minimum water levels upstream of the barrage, and a further reduction in the mean velocities.

Airborne Infrared Remote Sensing of Riverine Currents

Measurements of surface currents have been made in a variety of rivers and estuaries to evaluate the accuracy and robustness of techniques based on airborne infrared (IR) imaging of the advection of small-scale temperature variations. The imaging system is a modification of our Airborne Remote Optical Spotlight System to include a midwave IR camera. This system collects image sequences that are subsequently registered and mapped to the mean water level, providing space-time data proportional to water surface temperature along the watercourse. The temperature modulations are analyzed with two algorithms to assess the data and retrieve the currents. The full 3-D frequency-wavenumber spectrum is used to evaluate the signal and competing noise sources. A version of the maximum cross-correlation (MCC) algorithm, often used for measuring fluid motions, is applied to retrieve currents for most of the data analyzed here. The retrieved currents agree with the acoustic Doppler current profiler measurements with no mean bias and within 10 cm/s in 60% or more of ~ 1500 independent comparisons on multiple rivers. An error metric based on an MCC reciprocal filtering technique provides a numerical measure of confidence in each retrieval. Most bad points are flagged, as the retrieved current vector fields exhibit few obvious large errors. The density of retrieval postings is nominally one every 8-16 pixels or 8-16 m.

Long‐term impacts from damming and water level manipulation on flow and salinity regimes in Lake Urmia, Iran

AbstractLake Urmia in the north‐west of Iran is very large, very shallow and several times more saline than ocean water. The salinity of this terminal lake is of great ecological consequence for the existence and growth of Artemia Urmiana, a unique zooplankton endemic to the lake. It is a main food source for large bird populations. During the past decades, Lake Urmia has been strained by a number of anthropogenic and natural causes. They include extensive damming on the contributory rivers, building a dike‐type causeway and climate change. This paper deals with the long‐term impacts of damming, fresh water overexploitation and water level manipulation on flow and salinity conditions in Lake Urmia. For this purpose, the flow and salinity regimes were numerically simulated for the next four decades. The validity of the pseudo‐three‐dimensional hydrodynamic and advection‐dispersion models was assessed through sensitivity analysis of the models and comparing the simulated results against field measurements. The model predicted that because of damming on the rivers, the mean water level in the lake will possibly experience a drop of 2.2–2.8 m over next 40 years. The results indicated that, over decadal time periods, the lake most probably will be split into two interconnected smaller lakes. The northern lake was foreseen to become extremely saline, which will seriously threaten the Artemia's survival in this area. Over the long‐term periods, the southern lake seemed not to deviate much from its existing conditions. It however appeared to become more responsive to seasonal climatic changes and to the rivers inflow, as compared with its current conditions. Effects from climate changes were not considered in the current study.

Human impacts on tides overwhelm the effect of sea level rise on extreme water levels in the Rhine–Meuse delta

With the aim to link tidal and subtidal water level changes to human interventions, 70years of water level data for the Rhine–Meuse tidal river network is analysed using a variety of statistical methods. Using a novel parameterization of probability density functions, mean high and low water levels are examined, and extreme water levels are investigated by applying the combined Mann–Kendall and Pettitt tests to find trends and trend changes. Tidal water levels are studied based on harmonic analysis. Results show that the mean water levels throughout the system rise with the same pace as the mean sea level. However, high- and low water levels do not show the same increase, and the spatial variability in decadal trends in high- and low water levels is high. High water and low water extremes generally decrease. Both the extreme water level analysis and the harmonic analysis display significant trend breaks in 1970, 1981 and 1997. These breaks can be attributed to the closure of the Haringvliet estuary, the removal of sluices and the removal of a dam, respectively, which radically alter the tidal motion. These results demonstrate that the direct human influence on the tidal motion can overwhelm the effect of mean sea level rise on water level extremes.

Reproducing laboratory-scale rip currents on a barred beach by a boussinesq wave model

The pioneering work of Haller [8] on physically investigating bathymetry-controlled rip currents in the laboratory is a standard benchmark test for verifying numerical nearshore circulation models. In this paper, a numerical model based on higher-order Boussinesq equations was developed to reproduce the number of experiments involved in such an investigation, with emphasis on the effect of computational domain size on the numerical results. A set of Boussinesq equations with optimum linear properties and second-order full nonlinearity were solved using a higher-order finite difference scheme. Wave breaking, moving shoreline, bottom friction, and mixing were all treated empirically. The developed model was first run to simulate the rip current under full spatial and time-domain conditions. The computed mean quantities, including wave height, mean water level, and mean current, were compared with the experimental data and favorable agreements were found. The effects of computational domain size on the computation results were then investigated by conducting numerical experiments. The Willmott index was introduced to evaluate the agreements between the computed results and data. Inter-comparisons between the computation results and measurements demonstrated that the computational domain size significantly influenced the numerical results. Thus, running a Boussinesq wave model under full spatial and time-domain conditions is recommended to reproduce Haller's experiment.

Study on the Erosion Mechanism of the Bijia Mountain Gravel Tombolo, China

ABSTRACT Liang, S.; Sun, Z.; Sun, J., and Zhang, Z., 2014. Study on the erosion mechanism of the Bijia Mountain gravel tombolo, China. We investigated the mechanism of erosion on Bijia Mountain tombolo, a famous gravel tombolo in China. Both numerical simulation and experiment were carried out. First, the mechanism was deduced by reviewing changes in cross section, crest elevation, gravel composition, and overall shape in the tombolo between 1985 and 2005 and changes in wave condition near the tombolo. Then, an overall physical model test was carried out to verify this mechanism. Based on the experimental data, we conclude that the breaking of original balanced wave conditions is the main reason for the erosion. When the bidirectional alternating wave action changed into a unidirectional wave field, the original equilibrium was broken. Strong easterly waves (over 25 and 50 year return periods) eroded the tombolo, while wave effects from the ESE and SE directions at mean water level were the main causes of...

Comparison of Lake Ontario and St. Lawrence River hydrologic droughts and their relationship to climate indices

Five characteristics (intensity or magnitude, duration, frequency, timing, and variability) of drought, defined using the threshold level method (TLM) and recorded in mean annual water levels in Lake Ontario and the St. Lawrence River from 1918 to 2010, were compared. Timing is the only characteristic that is different for the two water bodies. For Lake Ontario, the most intense drought occurred in the 1930s, whereas in the St. Lawrence River, intense droughts took place in the 1960s and 2000s. The Lake Ontario drought produced two shifts in mean before (decrease) and after (increase) the 1930s. The change in variance that took place in the 1960s is thought to be related to the construction of locks during the digging of the seaway. The droughts that affected the St. Lawrence River had no impact on the stationarity (mean and variance) of the annual mean water level series. Analysis of the correlation between drought severity and climate indices revealed that years characterized by very weak to moderate drought are significantly correlated with PDO (Pacific Decadal Oscillation), while those characterized by intense drought are correlated with NAO (North Atlantic Oscillation). Both climate indices are negatively correlated with Lake Ontario water levels, while they are positively correlated with St. Lawrence River levels. The study suggests that NAO may be used to predict the driest years for the two water bodies.

Non-linear numerical modeling and experimental testing of a point absorber wave energy converter

A time domain model is applied to a three-dimensional point absorber wave energy converter. The dynamical properties of a semi-submerged hemisphere oscillating around a pivot point where the vertical height of this point is above the mean water level are investigated. The numerical model includes the calculation of the non-linear hydrostatic restoring moment by a cubic polynomial function fit to laboratory test results. Moreover, moments due to viscous drag are evaluated on the oscillating hemisphere considering the horizontal and vertical drag force components. The influence on the motions of this non-linear effect is investigated by a simplified formulation proportional to the quadratic velocity. Results from experiments are shown in order to validate the numerical calculations. All the experimental results are in good agreement with the linear potential theory as long as the waves are sufficiently mild i.e. H/λ≤0.02. For steep waves, H/λ≥0.04 however, the relative velocities between the body and the waves increase thus requiring inclusion of the non-linear hydrostatic restoring moment to effectively predict the dynamics of the wave energy converter. For operation of the device with a passively damping power take-off the moment due to viscous drag is found to be negligible.

Phragmites distribution relative to progressive water level decline in Lake Koronia, Greece

ABSTRACTLake Koronia is a hypertrophic Ramsar site in northern Greece. Water level dropped progressively from approximately 6 m in the mid‐1980s to 0·8 m in 2001 associated with over extraction of groundwater for agriculture, and the open water area has decreased from 4620 to 2930 ha, respectively. The resulting annual water level loss of 0·25–0·30 m year−1 was accompanied by expansion of Phragmites australis from a littoral fringe to dominance of exposed lake bottom areas from 97 ha in 1977 to 785 ha in 2005. The aim of this work was to apply an ecohydrological approach using remote sensing and geographic information system (GIS) to examine the movement of Phragmites relative to the water level retreat and to basin morphometry. Aerial expansion of Phragmites averaged 11–32 ha year−1 during the period of progressive water level decline but increased to 38–116 ha year−1 during a brief period of water level increase (2001–2003) as the plant colonized reflooded portions of the basin. The total area of Phragmites expanded 29% per annum during 1977–2005. Landward and lakeward margins of the Phragmites area followed water level retreat, moving 55 and 129 m, respectively, during the long period of progressive water level decline. Aerial movements of Phragmites in Lake Koronia are some of the highest reported in the literature. Mean water level within the Phragmites bed varied from 0·5 to 2·0 m during the period covered by this study. Very minor changes in basin slope, however, affected plant colonization rates, as evidenced by 200–250 ha/0·5 m water level drop at 0·18% basin slope to 360–1360 ha/0·5 m water level drop at 0·029% slope. The techniques applied to Lake Koronia for reconstructing past lake levels and associated distributions of Phragmites have broad application for understanding the dynamics of Phragmites elsewhere and anticipating periods of rapid plant expansion related to subtle changes in basin morphology. This study is useful for managing Phragmites populations in areas where efforts are being made to re‐establish populations as well as where elimination of invasive populations is sought. Copyright © 2013 John Wiley & Sons, Ltd.

Development of a numerical 2-dimensional beach evolution model

This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model is composed of 4 submodels: a nearshore spectral wave transformation model based on an energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the nonlinear shallow water equations to compute the nearshore depth-averaged wave-induced current velocities and mean water level changes, a sediment transport model to compute the local total sediment transport rates occurring under the action of wind waves, and a bottom evolution model to compute the bed level changes in time based on the gradients of sediment transport rates in cross-shore and longshore directions. The developed models are applied successfully to the SANDYDUCK field experiments and to some conceptual benchmark cases including simulation of rip currents around beach cusps, beach evolution around a single shore perpendicular groin, and a series of offshore breakwaters. The numerical model gave results in agreement with the measurements both qualitatively and quantitatively and reflected the physical concepts well for the selected conceptual cases.

Hydrological influences on the distribution of vegetation and tree height of Alnus japonica (Thunb.) Steud. in the Kushiro Mire, Japan

The relationship between the hydrology and plant communities assessed by continuous measurement of water, soil environment and vegetation, mainly in an alder forest, was studied in Kushiro Mire, Hokkaido, Japan. Seasonal changes in the water level were not detected, except in the willow forest located in the Kuchoro River, which showed a drawdown of the water level in summer. The height of the alder trees correlated with the mean and lowest water levels which would supply oxygen. The peak water level also affected the height of the alder forest, suggesting that waterlogging (reduction and lack of oxygen) inhibited the height of the alder trees. An overflow was only observed during the strong low pressure, typhoon or snowmelt flooding, as a result of the high peak water level. In snowmelt season, alder did not foliation stage. This suggests that the river water may only overflow the natural levee during a such large rain event, which supports the establishment of alder forests in the inflow area. Furthermore, the height of alder trees weakly negatively correlated with the carbon/nitrogen ratio of the soil, suggesting a difference in the deposition of peat. Reed-sedge community showed a large fluctuation of the water level, and resistant to drawdown of the water level, which would inhibit the invasion of alder.

气候变化对鄱阳湖水位变化的影响分析

水位变化直接关系鄱阳湖流域防汛抗旱的科学决策、水资源的高效利用、水生态健康以及湖区经济的可持续发展。利用鄱阳湖各站点的平均日降水、气温和水位资料，建立了三层反向传播神经网络模型(BP- NNM)。基于统计降尺度方法把全球气候模式BCC-CSM1-1输出结果降解到流域尺度的气温和降水数据，输入到BP-NNM得到未来气候变化情景下鄱阳湖水位系列，对未来鄱阳湖的平均水位进行分析。研究结果表明：在RCP4.5情节下，鄱阳湖未来平均水位的多年均值变幅小于2.5%，但是平均水位的年际变化在各月份之间差异较大。The water level change directly relates to scientific decision-making of flood control and drought relief, efficient utilization of water resources, healthy of water ecology and sustainable development of economy in the Poyang Lake basin. Back Propagation Neural Networks Model (BP-NNM) was established based on observed daily temperature, precipitation and water level data series in this study region. The statistical downscale method was coupled with BCC-CSM1-1 global climate model to obtain basin scale air temperature and precipitation data series, and then as inputs of BP-NNM to simulate future water levels of the Poyang Lake. The future average water levels of the Poyang Lake were analyzed and discussed. The results show that the future annual mean water level change will less than 2.5% compared to the baseline period, but the inter-annual variability of water levels among months is large under RCP4.5 scenarios.

남강댐의 운영수위 변경에 따른 선버들 군락의 분포현황 및 특성

The present Namgang Dam had been completed in 2000, Salix subfragilis communities began to form in 2003 and their distribution area have been rapidly extended into nine times in 2010. In order to deduce correlation between water level and distribution of Salix subfragilis communities under this background in Namgang-dam reservoir, distribution characteristics and widening direction of Salix subfragilis communities have been analyzed by aerial photographs and water levels has been reviewed, also heights and ages of Salix subfragilis have been surveyed in field. The water levels of Namgang-dam related germination of Salix subfragilis have been analyzed in May and June from 2000 to 2010, mean water level, minimum water level and maximum water level were 37.87m, 36.99m and 38.82m, respectively. The oldest ages were 9-13 years, average diameters of breast height, average heights, average numbers and average crown area were respectively 3.9-8.8cm, 3.8-7.5m, and in sites. Therefore, this results showed that the first recruitment of Salix subfragilis was in May 2002 when water levels have been maintained as 38.76-41.31m and the widening of Salix subfragilis communities was in May 2004 and 2005 when mean minimum water levels have been maintained as 38.76-41.31m. Salix subfragilis communities formed climax forest in Namgang-dam shore, this phenomena were different from the succession processes of Salix in rivers appeared landforming by deposition of sediment.

Comparison of Extreme Offshore Structural Response from Two Alterna-tive Stretching Techniques

Linear random wave theory (LRWT) has successfully explained most properties of real sea waves with the ex-ception of some nonlinear effects for surface elevation and water particle kinematics. Due to its simplicity, it is frequently used to simulate water particle kinematics at different nodes of an offshore structure from a reference surface elevation record; however, predicted water particle kinematics from LRWT suffer from unrealistically large high-frequency compo-nents in the vicinity of mean water level (MWL). To overcome this deficiency, a common industry practice for evaluation of wave kinematics in the free surface zone consists of using linear random wave theory in conjunction with empirical techniques (such as Wheeler and vertical stretching methods) to provide a more realistic representation of near-surface wave kinematics. It is well known that the predicted kinematics from these methods are different; however, no systematic study has been conducted to investigate the effect of this on the magnitude of extreme responses of an offshore structure. In this paper, probability distributions of extreme responses of an offshore structure from Wheeler and vertical stretching methods are compared. It is shown that the difference is significant; consequently, further research is required to deter-mine which method is more reliable.

Coastal flooding in Scituate (MA): A FVCOM study of the 27 December 2010 nor'easter

[1] A nested Finite-Volume Coastal Ocean Model (FVCOM) inundation forecast model has been developed for Scituate (MA) as part of the Northeast Coastal Ocean Forecast System (NECOFS). Scituate Harbor is a small coastal lagoon oriented north-south with a narrow entrance (with opposing breakwaters) opening eastward onto Massachusetts Bay and the Gulf of Maine. On 27 December 2010, a classic nor'easter produced a ∼0.9 m high surge, which when added to the ∼1.5 m high tide and seasonal higher mean water level, produced significant inundation in Scituate. The Scituate FVCOM inundation model includes flooding/drying, seawall/breakwater, and wave-current interaction capabilities, and was driven by one-way nesting with NECOFS. Hindcasts of the 27 December nor'easter event were made with two different resolution Scituate FVCOM grids with and without inclusion of wave-current interaction to examine the influence of spatial resolution and model dynamics on the predicted flooding. In all simulations, a wind-driven coastal current flowed southward across the harbor entrance, with an attached separation eddy forming downstream of the northern breakwater and rapid decrease in wave energy entering the harbor. With wave-current interaction, the southward coastal current was strongly enhanced and currents within the separation eddy increased to more than 1 m/s, making it highly nonlinear with large lateral shears. Comparisons of the model water elevation time series with harbor tide station measurements showed that inclusion of wave-current interaction increased the peak model surge by ∼8 cm, in closer agreement with the observed peak.