Complex Estuarine System Research Articles

Abundance, Sex and Size Distribution of European Green Crabs, Carcinus maenas (Linnaeus, 1785), at Natural and Aquacultured Oyster Areas in Great Bay Estuary, NH

ABSTRACTGreat Bay Estuary (GBE) is a complex estuarine system at the convergence of seven rivers, ocean and land. The GBE ecosystem supports typical estuarine species but, like many estuaries, has been a target of both invasive and range‐expanding species. The goal of this study was to compare abundance, sex and size distribution of green crabs between oyster farm sites and non‐farmed sites within GBE in 2021 and 2022. Overall catch was higher in 2021 compared to 2022. The highest population of green crabs was estimated to be in the farm area around Cedar Point, and natural/restoration area near Moody Point had the smallest European green crab population. In both years, the majority of green crabs captured (98%) were adult males, and few were juveniles captured. At the last sampling date of 2021 and 2022, most crabs were large (68 ± 0.5 mm and 63 ± 2 mm carapace width, respectively). Shellfish growers, restoration and management teams could use these data in mitigation strategies to sustain industries and enhance GBE health. This information is important for oyster restoration initiatives and oyster growers as they may want to: consider putting traps around their restoration reefs and farms to help reduce green crab infestation/predation in their growing areas; make decisions regarding best management practices and optimal growing locations when applying for permits; and work with management teams with gear improvement, such as floating gear, to reduce green crab intrusion into cages. High‐priority locations for trapping should be areas such as oyster farms, oyster reefs and restoration sites.

An automatic mesh generator for coupled 1D–2D hydrodynamic models

Abstract. Two-dimensional (2D), depth-averaged shallow water equation (SWE) models are routinely used to simulate flooding in coastal areas – areas that often include vast networks of channels and flood-control topographic features and/or structures, such as barrier islands and levees. Adequately resolving these features within the confines of a 2D model can be computationally expensive, which has led to coupling 2D simulation tools to less expensive one-dimensional (1D) models. Under certain 1D–2D coupling approaches, this introduces internal constraints that must be considered in the generation of the 2D computational mesh used. In this paper, we further develop an existing automatic unstructured mesh generation tool for SWE models, ADMESH+, to sequentially (i) identify 1D constraints from the raw input data used in the mesh generation process, namely the digital elevation model (DEM) and land–water delineation data; (ii) distribute grid points along these internal constraints, according to feature curvature and user-prescribed minimum grid spacing; and (iii) integrate these internal constraints into the 2D mesh size function and mesh generation processes. The developed techniques, which include a novel approach for determining the so-called medial axis of a polygon, are described in detail and demonstrated on three test cases, including two inland watersheds with vast networks of channels and a complex estuarine system on the Texas, USA, coast.

Modeling Extreme Water Levels in the Salish Sea: The Importance of Including Remote Sea Level Anomalies for Application in Hydrodynamic Simulations

Extreme water-level recurrence estimates for a complex estuary using a high-resolution 2D model and a new method for estimating remotely generated sea level anomalies (SLAs) at the model boundary have been developed. The hydrodynamic model accurately resolves the dominant physical processes contributing to extreme water levels across the Washington State waters of the Salish Sea, including the relative contribution of remote SLA and other non-tidal residual processes that drive extreme water levels above the predicted tide. The model’s predictions have errors of less than 15 cm (<5% of 3–4 m tidal range) at eight tide gauge locations across the model domain. The influence of remote SLAs at the seaward boundary of the model was implemented using a multivariate regression of readily available and locally relevant wind, sea surface temperature, and pressure anomaly data, combined with El Niño Index data (R2 = 0.76). The hydrodynamic model simulations using the remote SLA predictor compared well with simulations using the widely used data-assimilative global ocean model HYCOM SLA data (root mean square difference of 5.5 cm). Extreme water-level recurrence estimates with and without remote SLA show that remote forcing accounts for 50–60% of the total water level anomaly observed along Salish Sea shorelines. The resulting model simulations across decadal timescales provide estimates of extreme water level recurrence across the Salish Sea, capturing climate variability important to long-term coastal hazard planning. This approach has widespread applications for other complex estuarine systems.

Seasonal Variability of the Ocean Circulation in Queen Charlotte Strait, British Columbia

ABSTRACT Queen Charlotte Strait (QCST) is a large marine area separating northern Vancouver Island from the British Columbia mainland. Although it is an important waterway connecting Queen Charlotte Sound with Johnstone Strait and eventually the Strait of Georgia, complex dynamics in QCST, including tides, surface winds, river runoffs, and coastal currents, are yet understudied. In this numerical study, a high-resolution (up to approximately 10 m in the horizontal) model was developed for QCST and adjacent areas to investigate the circulation in the strait, using the unstructured grid, Finite-Volume, primitive equation Community Ocean Model (FVCOM). Two operational larger-scale models force the FVCOM model: the Coastal Ice Ocean Prediction System for the West coast (CIOPS-W) at the open ocean (one-way nesting), and the High-Resolution Deterministic Prediction System (HRDPS) at surface boundaries. Prevailing winds over QCST are southeasterly in winter and northwesterly in summer and the model demonstrated the capacity to reproduce the ocean circulation regimes in both seasons of 2019. Complex empirical orthogonal function (CEOF) and correlation analyses determined that surface winds play a dominant role on the variability of residual flow in QCST in the winter, while river runoffs strongly influence the variability during the summer. The analyses highlight that QCST is a complex estuarine system with significant seasonal variability rather than just a simple conduit between Queen Charlotte Sound and the Strait of Georgia.

Assessing compound flooding potential with multivariate statistical models in a complex estuarine system under data constraints

AbstractCompound flooding may result from the interaction of two or more contributing processes, which may not be extreme themselves, but in combination lead to extreme impacts. Here, we use statistical methods to assess compounding effects from storm surge and multiple riverine discharges in Sabine Lake, TX. We employ several trivariate statistical models, including vine‐copulas and a conditional extreme value model, to examine the sensitivity of results to the choice of data pre‐processing steps, statistical model setup, and outliers. We define a response function that represents water levels resulting from the interaction between discharge and surge processes inside Sabine Lake and explore how it is affected by including or ignoring dependencies between the contributing flooding drivers. Our results show that accounting for dependencies leads to water levels that are up to 30 cm higher for a 2% annual exceedance probability (AEP) event and up to 35 cm higher for a 1% AEP event, compared to assuming independence. We also find notable variations in the results across different sampling schemes, multivariate model configurations, and sensitivity to outlier removal. Under data constraints, this highlights the need for testing various statistical modelling approaches, while the choice of an optimal approach remains subjective.

Distinguishing multiple Zn sources in oysters in a complex estuarine system using Zn isotope ratio signatures

The Pearl River Estuary (PRE), the largest estuary in Southern China, historically has suffered from metal contamination as a result of inputs from different riverine discharges. Determining the sources of metals accumulation in local aquatic flora and fauna remains a great challenge for this estuarine system with complex water circulation. In this study, Zn isotope ratios were measured in local oysters (Crassostrea hongkongensis) collected at 8 locations in the estuary on four occasions from 2014 to 2018, to better understand and assess the contamination sources. The results showed no significant differences (p < 0.05) in δ66Zn values in oysters among the four sampling dates within individual sites. However, approximately a 0.67‰ (range from -0.66‰ to 0.01‰) difference in average δ66Zn values was consistently found in oysters collected from the east side of the estuary compared to the west side, despite their comparable Zn concentrations. A mixing model was subsequently used to estimate the relative contributions from various sources to the δ66Zn values in these oysters. The mixing model predicts that zinc derived from the dissolved fraction (approximately 80 %) was the dominant uptake pathway for oysters collected at the east shore whereas approximately 50 % of the Zn in oysters collected at the west shore was derived from the particulate fraction. The mixing model also was used to estimate the relative impacts of fresh versus saline water on the measured δ66Zn values. Contributions from these two sources also varied between the east and west shores. This study presents the first data for Zn isotope ratios in oysters from the PRE, providing new insight for using Zn isotope ratios in oysters as a powerful tracer of sources in a complex estuarine system.

Water mass shapes the distribution patterns of planktonic ciliates (Alveolata, Ciliophora) in the subtropical Pearl River Estuary

Ciliates comprise essential components of microzooplankton in diverse marine environments. However, the extent to which environmental variables shape the distribution of planktonic ciliates in complex estuarine systems remains unclear. Here, 52 samples were collected from the Pearl River Estuary, China to reveal the influence of environmental variables on planktonic ciliate communities. Distinct community compositions of ciliates were found in three identified water masses: Pearl River diluted water mass, South China Sea surface water mass, and South China Sea bottom water mass. Significant differences in abundance, biomass, cell size, and oral diameter structure of ciliates were also detected among the three water masses. The partial Mantel test showed that water mass (as represented by water temperature and salinity) surpassed other environmental variables to be the primary factor driving the dynamics of the ciliate community. This study revealed the controlling mechanisms of planktonic ciliate communities in a subtropical, hydrographically complex estuarine ecosystem.

Tidal stream energy resource characterization in the Salish Sea

The Salish Sea, a large estuary on the Pacific Northwest coast, represents a great tidal stream resource because of its strong tidal currents in many tidal channels. However, the tidal energy resource in the Salish Sea has not been systematically characterized. This paper presents a modeling study conducted to characterize the tidal energy resource in the Salish Sea based on a high-resolution tidal hydrodynamic model, which was validated using data derived from 10 tide gauges and 132 current stations. A total of 16 tidal channels with strong currents were identified as hotspots for potential tidal energy development in the Salish Sea. Probability distributions and exceedance of the cross-channel average velocity were calculated at all 16 channels based on international standards for tidal energy resource characterization. The tidal energy resource at the 16 hotspots was also characterized using power density distributions and kinetic energy fluxes. The ranking of the kinetic energy fluxes suggested that Admiralty Inlet, Rosario Strait, and Middle Channel are the top three tidal energy hotspots in the Salish Sea. The study demonstrated the need of a high-resolution modeling framework for accurate simulation of tidal currents in large complex estuarine systems, in the context of tidal resource characterization and assessment.

Estuarine Circulation, Mixing, and Residence Times in the Salish Sea

AbstractA realistic numerical model is used to study the circulation and mixing of the Salish Sea, a large, complex estuarine system on the United States and Canadian west coast. The Salish Sea is biologically productive and supports many important fisheries but is threatened by recurrent hypoxia and ocean acidification, so a clear understanding of its circulation patterns and residence times is of value. The estuarine exchange flow is quantified at 39 sections over 3 years (2017–2019) using the Total Exchange Flow method. Vertical mixing in the 37 segments between sections is quantified as opposing vertical transports: the efflux and reflux. Efflux refers to the rate at which deep, landward‐flowing water is mixed up to become part of the shallow, seaward‐flowing layer. Similarly, reflux refers to the rate at which upper layer water is mixed down to form part of the landward inflow. These horizontal and vertical transports are used to create a box model to explore residence times in a number of different sub‐volumes, seasons, and years. Residence times from the box model are generally found to be longer than those based on simpler calculations of flushing time. The longer residence times are partly due to reflux, and partly due to incomplete tracer homogenization in sub‐volumes. The methods presented here are broadly applicable to other estuaries.

Modeling assessment of storm surge in the Salish Sea

This paper presents a modeling assessment of storm surge in the Salish Sea—a large and complex estuarine system in the Pacific Northwest that is exposed to extratropical cyclones. A method was developed to systematically identify storm surge events in the Salish Sea based on water level records at four representative tidal gauges in the Salish Sea. The maximum storm surge distribution in the Salish Sea was calculated based on model simulations of 34 major historical storm events from 1980 to 2016. The model simulations were validated by field observations of water level and velocity using a suite of model performance metrics. Model results suggest that the maximum storm surge in the Salish Sea is generally in the range of 0.8 m–1.03 m and is heterogeneous in space. The model results also show a strong north-south gradient with larger surge magnitudes occurring in the north that is primarily caused by the southerly wind in winter months. The sensitivity analysis of wind forcing suggested that storm surge in the Salish Sea is dominated by the remote surge from the Pacific Ocean, and the local wind contributes up to approximately 20% of the surge variability. This paper systematically elucidates storm surge characteristics and potential risk in the Salish Sea.

An operational forecasting system for physical processes in the Santos-Sao Vicente-Bertioga Estuarine System, Southeast Brazil

We describe the design, implementation, and performance of a fully automated Santos Operational Forecasting System (SOFS), built to monitor and predict short-term (< 3 days) sea surface elevations, currents, temperature, and salinity in the Santos-Sao Vicente-Bertioga Estuarine System (SSVBES). The SSVBES located at 24.0∘S, 46.3∘W is a complex estuarine system with many interconnected channels and two connections with the open sea. The system is prone to storm tides that bring coastal flooding to and interrupt ship traffic through Santos Port. The SOFS hydrodynamic module is based on the Princeton Ocean Model (POM) version POM-rain. The SSVBES model grid is forced by tides, winds, and river runoff and is nested into a coarse-resolution South Brazil Bight (SBB) grid. The SBB grid is forced by winds, density gradients, and the Brazil Current flowing offshore. Within SSVBES, SOFS works in parallel with three real-time observation stations. The model performance was tested against observed data with a best Willmott skill of 0.97 and root mean square error (RMSE) of 13.0 cm for tidal sea level (15.9% of the mean tidal range). For tidal currents, the best skill and RMSE were above 0.99 and 3.9 cm/s (4.3% of the mean tidal current range), respectively. The coupled system was able to simulate seven storm tides with average skill of 0.95 and average RMSE of 17.0 cm. The good agreement with observed data shows the potential use of the designed system to protect both human life and assets.

Modeling analysis of the swell and wind-sea climate in the Salish Sea

Accurate model hindcast of wave climate in complex estuarine systems is challenging because high-resolution wave models and wind forcing are required. In this study, a modeling approach using the unstructured-grid Simulating WAves Nearshore and a wind product from a high-resolution regional Weather Research and Forecasting hindcast was used to simulate the swell and wind-sea climate in the Salish Sea, a large estuary with many interconnected waterways on the Pacific Northwest coast of North America. The model hindcast was validated with observed data at five wave buoys. Spatial distribution and seasonal variations in wave climate in the Salish Sea were analyzed. Of the three major basins in the Salish Sea, the Strait of Juan de Fuca has the largest waves and is dominated by swells propagated from the Pacific Ocean. Significant wave heights in the Strait of Georgia have spatial and seasonal distribution patterns similar to those found in the Strait of Juan de Fuca. Waves in Puget Sound are small and primarily dominated by the wind-sea climate. Strong seasonal variations are observed in the Strait of Juan de Fuca and Strait of Georgia, but there is little seasonality of wave climate in Puget Sound. The high-resolution wave hindcast conducted in this study provides a comprehensive and important data set for better understanding the role of wave climate in coastal processes and natural hazards assessment in the Salish Sea.

Coupling between Hydrodynamics and Chlorophyll a and Bacteria in a Temperate Estuary: A Box Model Approach

The spatial patterns of chlorophyll a and bacteria were assessed in a temperate Atlantic tidal estuary during seasonal surveys, as well as in consecutive summer spring and neap tides. A box model approach was used to better understand spatial and temporal dynamics of these key estuarine descriptors. The Lima estuary (NW Portugal) was divided into boxes controlled by salinity and freshwater discharge and balance equations were derived for each variable, enabling the calculation of horizontal and vertical fluxes of plankton and, therefore, production or consumption rates. Chlorophyll a tended to burst within the oligohaline zone, whereas higher counts of bacteria were found in the mesohaline stretch. Whenever the water column was stratified, similar tide-independent trends were found for chlorophyll a and bacterial fluxes, with net growth in the upper less saline boxes, and consumption beneath the halocline. In the non-stratified upper estuary, other controls emerged for chlorophyll a and bacteria, such as nitrogen and carbon inputs, respectively. The presented results show that, while tidal hydrodynamics influenced plankton variability, production/consumption rates resulted from the interaction of additional factors, namely estuarine geomorphological characteristics and nutrient inputs. In complex estuarine systems, the rather simple box model approach remains a useful tool in the task of understanding the coupling between hydrodynamics and the behavior of plankton, emerging as a contribution toward the management of estuarine systems.

An environmental flow determination method for integrating multiple-scale ecohydrological and complex ecosystem processes in estuaries

This paper presents an environmental flow methodology that was developed to accommodate shallow, highly dynamic micro-tidal estuaries found along the wave-dominated coast of South Arica. This method differs to most other approaches that primarily focus on larger permanently open systems having unrestricted inlets. Following an adaptive, design science research approach, the 7-step method adopted both ecohydrological and ecosystem-based concepts, encapsulating key hydrologicalhydrodynamic-biogeochemical processes, as well as biotic responses. The procedure also addresses a key challenge often encountered in applying these approaches to complex estuarine systems - the mismatch of temporal and spatial scales between abiotic processes and biotic responses. The method simplifies and aggregates abiotic processes to appropriate scales suitable for analysis of biotic responses, by introducing concepts such zoning and major physical states that characterize an estuary. The method's flexibility in data requirements lends itself to applications in countries where data is limited or where differences exist in data quality between systems. Essential in any environmental flow determination process, however, is long-term monitoring to incrementally improve confidence of the input data, but also to evaluate whether allocated flows achieve desired objectives set. Future challenges include refining the method to accommodate flow changes within much shorter timeframes and in conjunction with escalating global change pressures amongst other; pollution, living resource exploitation and physical destruction of habitat.

Wind influence on the orientation of estuarine landforms: An example from Lake Illawarra in southeastern Australia

AbstractWe propose a type of a quasi‐equilibrium, which describes a convergence of the estuarine system towards a form whose planimetric orientation is along the prevailing winds. By using the microtidal Lake Illawarra in southeastern Australia as an example, we describe sediment convergent and divergent processes that induce such an equilibrium controlled by the complex configuration of the shoreline relative to the prevailing winds. For a complex estuarine sedimentary system with a mixture of non‐cohesive and cohesive sediments, alongshore distribution of fluvial or marine sand deposition and associated subaqueous morphology reflects alongshore redistribution of sediments from rivers and the tidal inlet. The orientation of the second‐order polynomial trend surface of estuarine morphology is consistent with prevailing wind directions. Along the lake shore, there are extensive narrow flats mainly covered by fluvial or marine sands shaped by the prevailing winds. The implementation of the Delft3D flow model coupled with the SWAN wave model driven by idealized prevailing winds indicates the potential of sediment convergent and divergent transport at the embayment and promontory shoreline, which appears to be similar to the alongshore distribution of sandy sediments and the nearshore flats. Alongshore transport of sandy sediments is primarily induced by the wave refraction on the shore, while the currents are more effective in transporting fine‐grained sediments such as mud or clay. Finally, we suggest a conceptual model that describes potential sediment transport of convergence and divergence on the embayment or promontory shoreline that is normal to the prevailing winds. Orientation of the estuary follows the convergence centre of sediment transport driven by the prevailing winds with the largest fetch. A quantitative threshold for such sediment redistribution may be determined in the future. © 2018 John Wiley &amp; Sons, Ltd.

An Unstructured-Grid Based Morphodynamic Model for Sandbar Simulation in the Modaomen Estuary, China

The Modaomen Estuary is the most important passageway in discharging flood and sediment of the Pearl River Delta, which is one of the most complex estuarine systems in China. Due to the coupling effect among tidal currents, waves, and sediments, an immense sandbar area evolved in the outer subaqueous delta, impeding the flood releasing during wet season, as well as salinity intrusion during the dry season. In this work, an unstructured-grid based morphodynamic model was proposed to simulate the sandbar evolution process in the Modaomen Estuary. The proposed model was constructed by using the two-dimensional shallow water equations for tidal flow, the advection-diffusion equations for salinity and suspended sediment transport, and the non-equilibrium formulation of the Exner equation for bed evolution. To simulate the wave-induced longshore currents in the Modaomen Estuary, an adaptive time-stepping approach was proposed to couple the unstructured-grid based Simulating WAves Nearshore (SWAN) model and the shallow flow model. An integrated solver is proposed for computing flow, salinity, and sediment transport fluxes simultaneously, and then the shallow water equations and advection-diffusion equations are jointly solved by a high-resolution, unstructured-grid Godunov method. Application of the model to the Modaomen Estuary, using calibrated parameter values, gives results comparable to the measured data. The butterfly shape of the sandbar in the Modaomen Estuary is considerably well simulated by the proposed model, which matches well with the measured topography.

Accounting for multiple stressors influencing living marine resources in a complex estuarine ecosystem using an Atlantis model

Many external stressors influence marine and coastal ecosystems. Understanding effects of these stressors is important for managers concerned with living marine resources (LMR). Historically, analytical methods for understanding these effects have been limited to a relative few stressors being modelled. Recent work has shown that multiple stressors may commonly have non-additive or cumulative effects, so accounting for the interactions of such stressors on LMR populations may be important. Coastal and marine ecosystems, which are often important for early life stages of many LMR populations, have a wide variety of stressors, yet analytical approaches accounting for the dynamics of multiple stressors have been used infrequently in these types of systems. For this work, we simulate the effects of individual and multiple stressors on a complex estuarine system, the Chesapeake Bay (USA), to demonstrate the range of conclusions about the effects of stressors on LMR populations that might be reached if stressors are considered singly versus in combination. Temperature increase has the greatest effect on productivity in our simulations, and appears to be the dominant stressor currently affecting this system. Consequently, we suggest it may be important for future work focusing on the effects of other factors to also consider the effects of expected temperature increase in this system, or important non-additive trends could be missed. With recent improvements in processing speed, full system models like Atlantis have become effective tools to provide resource managers with the information regarding non-additive effects of multiple stressors that they need for sound decision making.

A coupled wave–current–sediment transport model for an estuarine system: Application to the Río de la Plata and Montevideo Bay

Modelling the hydrodynamics and fine-sediment dynamics in estuarine environments is important for coastal engineering design and environmental assessment. This paper presents the application of a coupled wave–current–sediment transport model to a complex estuarine system with high spatial resolution in a harbour area. The case study was the Río de la Plata, with a focus on the Montevideo Bay area. We used a bidimensional depth-averaged approach, and the sediment transport modelling focused on fine cohesive sediments. The model considers realistic forcings, allows for the simulation of complex geometries such as those present in harbour basins and is capable of providing long-term environmental simulations (on the order of several years) within reasonable computational times. The model results are in good agreement with the measured data and satisfactorily represent the main features of the flow and sediment dynamics of the Río de la Plata. The effect of the internal coupling on the hydrodynamic results is analysed, and the computational times with various coupling alternatives are discussed. The dynamics of fine sediment in Montevideo Bay were analysed based on the model results. The current-induced bottom shear stress results are relevant for representing the permanent suspended sediment concentrations, whereas the wave-induced bottom shear stress is fundamental for reproducing the main resuspension events during storm conditions. The suspended fine-sediment dynamics in the estuary are strongly controlled by the sediment exchange between the bed and water column, whereas inside Montevideo Bay, the dynamics are controlled mainly by advection of sediment originating from the nearby coastal area.

Fuzzy cognitive mapping in support of integrated ecosystem assessments: Developing a shared conceptual model among stakeholders

Ecosystem-based approaches, including integrated ecosystem assessments, are a popular methodology being used to holistically address management issues in social–ecological systems worldwide. In this study we utilized fuzzy logic cognitive mapping to develop conceptual models of a complex estuarine system among four stakeholder groups. The average number of categories in an individual map was not significantly different among groups, and there were no significant differences between the groups in the average complexity or density indices of the individual maps. When ordered by their complexity scores, eight categories contributed to the top four rankings of the stakeholder groups, with six of the categories shared by at least half of the groups. While non-metric multidimensional scaling (nMDS) analysis displayed a high degree of overlap between the individual models across groups, there was also diversity within each stakeholder group. These findings suggest that while all of the stakeholders interviewed perceive the subject ecosystem as a complex series of social and ecological interconnections, there are a core set of components that are present in most of the groups' models that are crucial in managing the system towards some desired outcome. However, the variability in the connections between these core components and the rest of the categories influences the exact nature of these outcomes. Understanding the reasons behind these differences will be critical to developing a shared conceptual model that will be acceptable to all stakeholder groups and can serve as the basis for an integrated ecosystem assessment.

An assessment of water quality monitoring tools in an estuarine system

Ocean colour remote sensing (OCRS) has proved to be a powerful tool in monitoring biogeophysical and optical water quality variables. The different capabilities of OCRS in terms of spatial extent and temporal or revisit cycle dictate some of scientific questions we can resolve in a qualitative or quantitative manner. Typically, near-water surface platform measurements of (RRS) have minimal uncertainties, high spectral and temporal resolution but tend to have limited spatial coverage in contrast to measurements from satellite platforms. To this end, we completed correlation tests among salinity, turbidity and above-water RRS from the Wadden Sea time series station Spiekeroog to determine the extent of their respective associations. Strong correlations were then utilized to establish empirical predictive regression models to infer salinity and turbidity from above-water RRS. These regression models were determined to have reasonable average uncertainties of less than 29%. As satellites generally provide wider spatial coverage, we assessed the feasibility of applying these near-water OCRS regression models to the high spatial resolution (30m) Operational Land Imager Landsat-8 imagery. Unbiased percent differences between above-water and satellite derived RRS at (443, 483, 561, and 655)nm centred wavebands were less than 22%. At high water level, basin tidal channels and creeks could be identified from Landsat-8 RGB composite imagery. This case study demonstrated potential applications of high spatial resolution (30m) Landsat-8 imagery in both qualitative and quantitative observations of water quality variables as well as features in an optically complex estuarine systems. The observations of water quality variables from three platforms submerged, near water surface and satellite is also shown to provide comparable measurements giving some form of an accuracy and precision test. The study findings here highlight the need to take advantage and improve high spatial resolution OCRS approaches and predictive regression models for such optically complex estuarine waters for realistic multidisciplinary efforts to continuously observe water constituents.