Decades ago, the marsh was connected to the Upper Newport bay and at that time had received tidal input. The marsh has been cut off from the bay because of human activity and urban development and now receives freshwater from nearby wells. This does not completely explain why there is still high salinity in the marsh. The ground on and adjacent to the dikes is elevated above the water-saturated marsh and hence is drier. It is also the regions of high soil salinity and where a process called wicking occurs.
Water then reaches the top of the dike and evaporates, leaving the salts behind.
This can occur for many months in the dry season thus the soil on the dikes can become very salty. Wicking also occurs in this region hence providing for the salty ideal conditions for pickleweed colonization. The pickleweed found in the San Joaquin Freshwater Marsh is the perennial species Salicornia virginica . It is a low-growing, fleshy plant with a jointed main stem with oppositely arranged branches. Pickleweed forms dense canopies along the paths on top of the dikes or in the drier areas adjacent to the dikes.