The quality of freshwater inflow changes the distribution of nutrients, sediments, organisms, and organic material in an estuary. Estuarine alterations have possible consequences that alter ecosystem dynamics and productivity (Alber 2002). Freshwater inflow is usually positively correlated with sediments and nutrients including nitrogen.
Freshwater inflow can enhance nutrients and increase primary production in estuaries (Palmer et al. 2002). The often-large nutrient concentrations freshwater inflows carry into estuaries has been correlated with nitrogen loading and phytoplankton production (Flint et al. 1986; Nixon 1992; Mallin et al. 1993; Boynton et al. 1995, referenced in Alber 2002). In a study done on restored freshwater inflows to Nueces Delta, Texas, Polychaete Streblospio benedicti rapidly increased following a freshwater event (Palmer et al. 2002). This primary production is a food source that can be consumed by bivalves or deposited onto sediment surfaces where it may be consumed by interface feeders such as polychaetes and crustaceans. The relationship between inflows and secondary production is difficult to determine due to the complexity of trophic structures but increased nutrient inflow is generally positively correlated with increases in secondary production (Alber 2002).
Water quality parameters can be measured using a water quality sonde tool. Sondes can measure multiple parameters at the same time including salinity, ph, dissolved oxygen, conductivity, temperature, nitrate, ammonium, and more depending on the brand of sonde.