Study on salt release intensity from sediments and influencing factors in coastal reservoirs: combining small-medium-large experiments.

Water salinization is one of the major environmental concerns that endangers water supply security in northern China. To investigate the salt release intensity and influencing factors in reservoirs' daily operation, a series of experiments covered small-medium-large scale were conducted in laboratory, outdoor pool and coastal reservoir, respectively. The findings regarding salt release process in the three experiments were similar: the release fluxes curves follow the power function, y = axb (where y is the release fluxes, g m^-2 d; x is the time, t; a and b are constants). The maximum salt cumulative release intensity in small-scale experiments was 14.83 g m^-2 when stable, while that in medium-scale was 1,170.11 g m^-2 (79 times larger), and that in large-scale experiments was 1,875.02 g m^-2 (126 times larger). Water salinization was found to be more severe under the conditions featured by higher sediment salt content, higher temperature, lower operating water level and more intense disturbance of wind and rainfall, respectively. Furthermore, importing low Cl- concentration overlying water promoted salt release from sediment, and exchanging water frequently could remove the accumulated salt in water body. These findings could help to better estimate the salt release intensity and thus improve the construction, operation and management process of the coastal reservoirs. [ABSTRACT FROM AUTHOR]