Though there is widespread agreement that Spartina a]terniflora marshes absorb some wave energy, there is considerable question regarding the magnitude and importance of this process. It has been suggested that marshes are much like an array of vertical cyllnders in a water column. Based upon empirical estimates oF the fluid drag forces occurring on vertical cylinders and laboratory observations of various arrays of cylinders, a model was developed to describe wave decay in marshes.In 1981, a series of field experiments were conducted to test and calibrate this empirical model in a series of natural S. alterniflora marshes. The model with some modification was found to be very useful for describing wave decay in coastal marshes.

There have been many recent attempts to establish salt marshes in the coastal United States. Plantings are generally made for the purpose of shore protection, dredged material stabilization, or habitat development. During 1980 a survey was made of recent and historic salt marsh planting projects. Data were collected in 104 planted marshes in 12 coastal states. The relative stability of these plantings was compared to physical indicators of wave climate severity (fetch, shore slope, offshore depth, shore configuration, sediment grain size, orientation with respect to prevailing and storm winds, and proximity to boat traffic).Fetch, shore configuration, and sediment grain size were found to be related to planting stability. Using these parameters, a system was developed for evaluating potential marsh development sites.

The report was prepared by Paul L. Knutson, Coastal Ecology Branch, under the general supervision of R.M. Yancey. Illustrations were prepared by the author and L. Martin. Comments on this publication are invited.

No abstract

This report provides criteria for planting salt marsh vegetation to control erosion.It is intended to update information presented in "Planting Guidelines for Marsh Development and Bank Stabilization," CETA 77-3 (Knutson, 1977) and "Wetland Habitat Development with Dredged Material: Engineering and Plant Propagation," TR DS-78-16 (U.S. Army Engineer Waterways Experiment Station, 1978).The work was carried out under the coastal ecology research program of the U.S. Army Coastal Engineering Research Center (CERC).