LONGITUDINAL VARIATIONS OF SALT FLUXES IN A SHALLOW ESTUARY WITH HYPERSALINE RUNOFF

As a result of high evaporation rate, a salinity maximum zone or salt plug [4] is likely to occur in a lowinflow estuary in which salinity is higher inside the salt plug than both its seaward and landward directions. The freshwater lens estuary (FLE) which we describe here, as a unique phenomenon, might occur when a hypersaline runoff from the watershed follows an almost freshwater river discharge with a time lag of few hours/days. Such a condition is likely to occur when a source of salinity exists in the watershed. This condition ismet for the Mond River Estuary (see Figure 1) in the northern coast of the Persian Gulf, and occurs occasionally during wet season in which precipitation over a saline soilarea close to the river produces a rain-driven flood. This hypersaline water mass follows a freshwater river inflow and enters into the estuary Two at least 25-hour tidal cycles of velocity, water level, temperature, and salinity were recorded at 4 stations along the estuary (see Figure 1). One period was selected during spring tide from 2 to 3 February 2014 (denoted by Experiment-1 hereafter) which included intense rain, and another period was during neap tide from 22 to 23 February 2014 (denoted by Experiment-2 hereafter). Theflood (18-21 February) was recorded in time series of the river inflow.