Studies have found that altering hydrology of freshwater inflows could cause changes in estuarine systems. Dewatering, or removal of freshwater before it reaches the estuary, causes changes in the structure and function of estuarine ecosystems (Palmer et al. 2011). Studies performed to assess effects of changing freshwater flows used benthic invertebrates and macrofaunal biomass as bioindicators: species that can be used to signify the condition of an ecosystem (Palmer et al. 2008). The ecosystem conditions can be defined as the state of ecological integrity and the functionality of connections between them (USEPA 2008). Therefore, changes in biomass correlated with changing freshwater inflows indicate that secondary production was changed with altered inflows (Kim et al. 2009).
Estuarine systems may experience changes in many components resulting from freshwater inflow fluctuations including hydroclimate, water quality, benthic communities, epibenthic communities, fish communities, invasive species, ecosystem services, and other water resources which have resulted in losses of habitat, biodiversity, and productivity (Montagna et al. 2002b).