• Login
    About WHOAS
    View Item 
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Geology and Geophysics (G&G)
    • View Item
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Geology and Geophysics (G&G)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of WHOASCommunities & CollectionsBy Issue DateAuthorsTitlesKeywordsThis CollectionBy Issue DateAuthorsTitlesKeywords

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Tidal circulation and flushing characteristics of the Nauset Marsh System : report to the Town of Orleans

    Thumbnail
    View/Open
    WHOI-97-11.pdf (4.043Mb)
    Date
    1997-07
    Author
    Aubrey, David G.  Concept link
    Voulgaris, George  Concept link
    Spencer, Wayne D.  Concept link
    O'Malley, Stephen P.  Concept link
    Metadata
    Show full item record
    Citable URI
    https://hdl.handle.net/1912/100
    Location
    Nauset Marsh
    Orleans, MA
    DOI
    10.1575/1912/100
    Keyword
     Tidal flushing; Water quality; Numerical modeling; Salt marshes; Water pollution 
    Abstract
    Various interested bodies (i.e., National Park Servce, Cape Cod Commssion, and the Town of Orleans) charged with management of the Nauset Marsh system on Cape Cod, MA, commissioned a study of the estuarine circulation within the Nauset system. Recent signficant morphological changes in the system have changed mixing processes and residence times for the embayment. This study specifically addressed the differing water circulation and residence times arising from a migrating single inlet (dominant condition) and dual inlet (1992-1996) situations. These residence times are to be used by the Cape Cod Commission to identify nitrogen-sensitive sub-embayments based on various assumptions of build-out and nutrient loading. The Nauset Marsh system has experienced considerable development in recent years; proper management of this resource area requires knowledge of the consequences of such development. Application of field observations of bathymetry, sea surface elevation, temperature, salinity and currents, leads to better understanding the physics of the system. These data, analyzed in various forms, served as input data for a numerical, two-dimensional circulation model of the embayment. The circulation model provided flow and discharge data with which the residence times were calculated. Bathymetric measurements defined the volumes of the various sub-embayments to be used in the calculation of residence times. Residence times were calculated for six sub-embayments of the system, defined on the basis of their common hydrodynamic and morphologic characteristics. Two scenarios were evaluated: one for the present single-inlet system, which is near typical for most system states, and one for a dual inlet system such as existed for a period of time from 1992 through 1996. Residence times were evaluated for twelve cases, to demonstrate the range of residence times that can be defined based on varing assumptions. For instance, residence times can be defined on the basis of mean low water volumes or mean water levels, the latter being the more conservative (yielding a longer residence time). In addition, residence times depend on whether spring tides, neap tides, or average tidal conditions are used. We provide data on all three conditions: the neap tidal case is the most conservative in the sense of providing a longer residence time. This case can serve as the basis for flushing if conservatism is desired. Finally, residence time can be defined based on the amount of time it takes for water to renew itself with water from adjacent sub-embayments, or more conservatively assuming renewal from the offshore waters (which are presumed to be cleaner). Based on these various inputs, assumptions and calculations, residence times for Salt and Mill ponds under conditions of a single inlet are the longest of the various sub-embayments. Town Cove is still relatively quickly renewed, though not as fast as the main channels serving the system. Flow pattern under dual-inlet condition does seem to be partioned well, with the northern inlet serving the northern part of the system and the southern inlet serving the southern part of the system, with litte hydrodynamc communication between the two divisions. This new hydrodynamc behavior results in shorter residence times under dual inlets than under a single inlet. Calculations indicate that the slowest flushing occurs in Mill and Salt ponds. The main body of the embayment, consisting of narrow channels between well-flushed salt marsh and tidal flats, flushes rapidly. Two-dimensional calculations show that Town Cove also flushes relatively rapidly, on average. However, its greater depth and occasional temperature stratification create conditions which might accumulate nutrients in bottom sediments, which, when released, can cause decrease in water quality (such as plankton blooms). A more sophisticated low-trophic level ecosystem model combined with vertical hydrodynamic structure could clarfy the dynamics of this process. This study provides a defensible basis for evaluating nutrient loading and potential eutrophication arising from development in the watershed around Nauset embayment. However, since morphological changes occur on a rapid basis in this area, the issue of residence time should be re-examined periodically. For instance, rapid onshore migration of the southern barrier beach is threatening closure of the south chanel, a condition which could adversely affect water quality in Nauset Harbor in the near futue. A process should be established to examine the sensitivity of residence times for rapidly changing morphology.
    Collections
    • Geology and Geophysics (G&G)
    • WHOI Technical Reports
    Suggested Citation
    Aubrey, D. G., Voulgaris, G., Spencer, W. D., & O’Malley, S. P. (1997). Tidal circulation and flushing characteristics of the Nauset Marsh System: report to the Town of Orleans. Woods Hole Oceanographic Institution. https://doi.org/10.1575/1912/100
     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      Depleted dissolved organic carbon and distinct bacterial communities in the water column of a rapid-flushing coral reef ecosystem 

      Nelson, Craig E.; Alldredge, Alice L.; McCliment, Elizabeth A.; Amaral-Zettler, Linda A.; Carlson, Craig A. (2011-01-11)
      Coral reefs are highly productive ecosystems bathed in unproductive, low-nutrient oceanic waters, where microbially-dominated food webs are supported largely by bacterioplankton recycling of dissolved compounds. Despite ...
    • Thumbnail

      Complexity of the flooding/drying process in an estuarine tidal-creek salt-marsh system : an application of FVCOM 

      Chen, Changsheng; Qi, Jianhua; Li, Chunyan; Beardsley, Robert C.; Lin, Huichan; Walker, Randy; Gates, Keith (American Geophysical Union, 2008-07-30)
      The tidal flooding/drying process in the Satilla River Estuary was examined using an unstructured-grid finite-volume coastal ocean model (FVCOM). Driven by tidal forcing at the open boundary and river discharge at the ...
    • Thumbnail

      Seagrass impact on sediment exchange between tidal flats and salt marsh, and the sediment budget of shallow bays 

      Donatelli, Carmine; Ganju, Neil K.; Fagherazzi, Sergio; Leonardi, Nicoletta (John Wiley & Sons, 2018-05-20)
      Seagrasses are marine flowering plants that strongly impact their physical and biological surroundings and are therefore frequently referred to as ecological engineers. The effect of seagrasses on coastal bay resilience ...
    All Items in WHOAS are protected by original copyright, with all rights reserved, unless otherwise indicated. WHOAS also supports the use of the Creative Commons licenses for original content.
    A service of the MBLWHOI Library | About WHOAS
    Contact Us | Send Feedback | Privacy Policy
    Core Trust Logo