Abstract A better understanding of flow and sediment dynamics in the lowermost portions large‐tropical rivers is essential to constraining estimates worldwide delivery ocean. Flow velocity, salinity, suspended‐sediment concentration were measured for 25 h at three cross sections tidal Song Hau distributary Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal low‐seasonal discharge, estuarine conditions varied dramatically between them. The system transitioned...

Abstract Robust assessments of ecosystem stability are critical for informing conservation and management decisions. Tidal marsh ecosystems provide vital services, yet globally threatened by anthropogenic alterations to physical biological processes. A variety monitoring modeling approaches have been undertaken determine which tidal marshes likely persist into the future. Here, we conduct most robust comparison metrics date, building on two foundational studies that had previously...

Interrelationships between hydrology and aquatic ecosystems are better understood in streams rivers compared to their surrounding floodplains. Our goal was characterize the of Everglades ridge slough floodplain ecosystem, which is valued for comparatively high biodiversity connectivity its parallel‐drainage features but has been degraded over past century response flow reductions associated with flood control. We measured velocity, water depth, wind velocity continuously 3 years an area...

Snow bedforms range in size from centimeters to kilometers and exhibit a variety of morphologies. They are critical understanding the local surface energy balance as they modulate interactions between snow or ice atmosphere, making them an important component Earth’s croysphere. Despite their significance, especially given that covers more than 10% annually, have been subject relatively few studies, particularly subarctic environments. Here we discuss formation evolution using...

Summary Despite growing interest and investment in salt‐marsh restoration, relatively few marshes subjected to restoration efforts have been systematically monitored assess physical trajectory or success. In south San Francisco Bay, California, USA, where 83% of wetlands were lost via human manipulation, the largest wetland effort on US west coast is currently underway, restoring approximately 6000 ha former salt‐production ponds mixed habitats. The Whale Tail–Cargill Mitigation complex Bay...

Abstract Submerged aquatic vegetation is generally thought to attenuate waves, but this interaction remains poorly characterized in shallow‐water field settings with locally generated wind waves. Better quantification of wave–vegetation can provide insight morphodynamic changes a variety environments and also relevant the planning nature‐based coastal protection measures. Toward that end, an instrumented transect was deployed across Zostera marina (common eelgrass) meadow Chincoteague Bay,...

Abstract Depositional environments along the tidal river downstream of Óbidos have been proposed as important sinks for up to one third sediment discharge from Amazon River. However, morphology intertidal floodplain and dynamics exchange this reach yet be described. River‐bank surveys in five regions reveal a distinct transition bank between upper, central lower reaches river. The upper tidal‐river is defined by prominent natural levees that control transfer water mainstem River its...

Abstract The Amazon River is the largest fluvial source of fresh water and sediment to global ocean has longest tidally influenced reach in world. Two major rivers, Tapajós Xingu, enter along its tidal reach. However, unlike most confluences, these are not one‐way conduits through which flow downstream towards sea. drowned‐river valleys (rias) at confluences Xingu with experience water‐level fluctuations associated only seasonal rise fall river network, but also semidiurnal tides that...

Recent major storms have piqued interest in understanding the responses of estuarine hydrodynamics and sediment transport to these events. To that end, flow velocity, wave characteristics, suspended-sediment concentration (SSC) were measured for 11 months at eight locations Chincoteague Bay, MD/VA, USA, a shallow back-barrier estuary. Daily breezes episodic generated sediment-resuspending waves modified velocity all sites, which occupied channel, shoal, sheltered-bay environments with...

Geomorphology is a fundamental control on ecological and economic function of estuaries. However, relative to open coasts, there has been little quantification storm-induced bathymetric change in back-barrier Vessel-based airborne mapping can cover large areas quickly, but detection difficult because measurement errors be larger than the actual changes over storm timescale. We quantified at several locations Chincoteague Bay, Maryland/Virginia, August 2014 July 2015 period using fixed,...

Abstract The growth (or decay) of salt marshes depends on suspended‐sediment flux into and out the marsh. Suspended‐sediment concentration (SSC) is a key element flux, SSC‐based metrics reflect long‐term sediment‐flux trajectories variety marshes. One metric, flood‐ebb SSC differential, correlates with area‐normalized sediment can indicate salt‐marsh resilience over months to years. We hypothesize that these may be relevant shorter time periods. With data from 13 channels, we show direction...

Abstract Mainstem–floodplain material exchange in the tidal freshwater reach of major rivers may lead to significant sequestration riverine sediment, but this zone remains understudied compared adjacent fluvial and marine environments. This knowledge gap prompts investigation floodplain‐incising channels found along banks their role facilitating water suspended‐sediment fluxes between mainstem floodplain. To evaluate role, how it evolves river with time, we measured level, flow velocity,...

Abstract Bay–marsh systems, composed of an embayment surrounded by fringing marsh incised tidal channels, are widely distributed coastal environments. External sediment availability, marsh-edge erosion, and sea-level rise acting on such bay–marsh complexes may drive diverse sediment-flux regimes. These factors reinforce the ephemeral dynamic nature marshes: material released erosion becomes part a exchange that fuels geomorphic evolution coupled system. The dynamics this determine balance...

FIGURE 1. Lower tidal portion of the Mekong River, site distributary channel investigations that were part 2014-2015 Tropical Delta Study.The river starts to bifurcate downstream Kratie, Cambodia, breaking into seven distributaries.The two largest are Song Hau and Tien.This article focuses on Hau, which is reported carry ~40% total water discharge (Nguyen et al., 2008).Note tides propagate up ~300 km upstream river's mouth, but saline marine waters only reach ~40 upstream.Discharge data...

Predicting the success of future investments in coastal and estuarine ecosystem restorations is limited by scarce data quantifying sediment budgets transport processes prior restorations. This study provides detailed analyses hydrodynamics fluxes a recently restored U.S. Pacific Northwest estuary, 61 ha former agricultural area near mouth Stillaguamish River Washington, USA. Water level, flow velocity, suspended-sediment concentration (SSC) were measured between 21 March 2014 1 June 2015 at...

First posted December 8, 2022 For additional information, contact: Pacific Coastal and Marine Science CenterU.S. Geological Survey2885 Mission St.Santa Cruz, CA 95060 A cascading set of hazards to coastal environments is intimately tied sediment transport includes the flooding erosion shorelines habitats that support communities, industry, infrastructure, ecosystem functions (for example, critical fisheries). This report summarizes modeling measurement data used evaluate budget Nisqually...

First posted January 2, 2008 Revised April 20, 2021 For additional information, contact: Director, Woods Hole Coastal and Marine Science CenterU.S. Geological Survey384 RoadQuissett CampusWoods Hole, MA 02543-1598 The U.S. Survey (USGS) Oceanographic Time-Series Measurement Database contains oceanographic observations made as part of studies designed to increase understanding sediment transport processes associated dynamics. Analysis these data has contributed more accurate prediction the...

First posted May 25, 2017 For additional information, contact: Director, Woods Hole Coastal and Marine Science Center U.S. Geological Survey 384 Road Quissett Campus Hole, MA 02543 scientists technical support staff measured oceanographic, waterquality, seabed-elevation-change, meteorological parameters in Chincoteague Bay, Maryland Virginia, during the period of August 13, 2014, to July 14, 2015, as part Estuarine Physical Response Storms project (GS2–2D) supported by Department Interior...

Extreme water-level recurrence estimates for a complex estuary using high-resolution 2D model and new method estimating remotely generated sea level anomalies (SLAs) at the boundary have been developed. The hydrodynamic accurately resolves dominant physical processes contributing to extreme water levels across Washington State waters of Salish Sea, including relative contribution remote SLA other non-tidal residual that drive above predicted tide. model’s predictions errors less than 15 cm...