The Chesapeake Bay and Tidal Tributary Interpolator computes water quality concentrations throughout the Chesapeake Bay and/or tributary rivers from water quality measured at point locations. Results of the Chesapeake Bay Interpolator have been used since 1988 to determine trends in water quality for the Chesapeake Bay Program . Interpolated monitoring data can be mapped to create pictures, as shown in the following example of dissolved oxygen in the Bay and tidal rivers, and by depth in the lower transect of the Bay.

Monitoring data are collected at over 50 stations in the Bay, and many more locations in the tidal rivers. Water samples are also measured at various depths from the water surface to the bottom. The resulting values represent the whole water body--the more samples that are measured, the better they represent the wide range of water quality in the Bay. At fixed distances (one kilometer or less), the Interpolator calculates a three-dimensional average value, using four or more measured values. The above image represents over 238,000 calculated values to represent a snapshot of water quality in Chesapeake Bay and its tidal rivers.

The calculated values can be further analyzed to determine trends in water quality through time. Such time series graphs can provide a better understanding of how the Bay responds to weather and climate patterns, and also to evaluate whether the Bay is improving because of the restoration program.

Results of the Chesapeake Bay Interpolator for the parameters Chlorophyll, Total Phosphorous, Dissolved Oxygen, Total Suspended Solids, Salinity, Water Temperature and Total Nitrogen from 1985 through 2005 can be browsed using the tool listed below. The Water Quality Image Search Tool has been developed to allow you to retrieve just those images you wish to view. The image database will be updated as additional water quality data becomes available.