Remote sensing Another type of monitoring of estuary quality is the use of remote sensing. Remotely sensed data from aircraft and satellites provide information about estuary systems. This satellite system transmits thermal and visible imagery from most of the Western Hemisphere every thirty minutes. This information is used to monitor and analyze coastal and deep-gulf circulation, coastal sediment transport, storm formation, oil spills, and vegetation conditions. Additional factors of Estuary quality Estuaries are places where fresh water from rivers and salt water from oceans mix.
Salinity is a major factor affecting the physical makeup of estuaries.
The salinity levels decrease as the estuary moves inland and as the volume of freshwater changes. Conductivity measurements correlate to salinity and the amount other dissolved solid in water. Wastewater discharge and fertilizer runoffs are activities that might change the conductivity of estuary water. EPA Test results During the 1991-93 testing periods, EPA rated the following estuary areas for quality. Tests included bottom life condition, DO, light penetration, sediment contaminants and fish pathology.