Sand Transport at the Floor of Long Island Sound

Abstract

This chapter deals with the distribution of sand and mud in Long Island Sound (LIS) and discusses the processes that control the sand-mud transitions. A simplified mass balance is used to describe the net transport of sand over an accreting mud bottom. The combination of these two sedimentary processes controls the transition from sand to mud on the floor of the LIS. The distribution of sand may be described with three parameters: an advection velocity of sand grains, an eddy-diffusion coefficient for mobile sand, and a rate of accumulation of marine mud. The motion of sand is thereby represented with a deterministic part and a statistical part. In this chapter, a mathematical model is applied to analyze the sand transportation. The transition zone is described using a one-dimensional form of the mass-balance equation. It is found that the sand–mud transition zone could be adequately represented by allowing the sedimentary processes to proceed at constant rates. The calculated sand flux then agrees with the sand flux that has been measured over the sand-wave field in the eastern LIS.