Mercury: mercury level from sampled fish in parts per million (ppm)
· Elevation: reservoir’s elevation (in feet)
· Drainage: drainage area (in square miles). A drainage area is the area of land which collects and drains the rainwater which falls on it, such as the area around a reservoir.
· Surface Area: surface area of a reservoir (in acres)
· Max. Depth: maximum depth of a reservoir (in feet)
· RF: Runoff Factor. Runoff is the amount of rainwater or melted snow that flows into rivers and streams. Higher runoff factors may lead to more surface waters from the reservoir watershed reaching reservoirs, influencing mercury concentration in fish.
· FR: Flushing Rate. The flushing rate is the number of times all water in a reservoir is theoretically exchanged during a year.
· Dam: Impoundment class (1 = no functional dam present; all natural flowages. 0 = at some man-made flowage in the drainage area)
· RT: Reservoir Type. Three types of reservoirs are identified (1 = oligotrophic. 2 = eutrophic. 3 = mesotrophic)
· RS: Reservoir Stratification. Two indicators are used (1 = reservoir is stratified. 0 = reservoir is not stratified). A reservoir is considered ‘stratified’ if a temperature decrease of ≥1 degree per meter exists with depth.
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Tasks
4. There are concerns among industrialists who are benefiting from dams and dam constructions that there will be claims that high mercury levels in fish are related to the presence of dams in the reservoir’s drainage. Does the data support or refute this claim? Provide some justifications.
