When scientists do a 'budget' of a water source, it helps to think of a bank account. You want to know how much goes in, and how much goes out, of your bank account. The amount that goes in to your bank account, or here - to the stream - are your inputs. The amount that leaves the bank account (is withdrawn), are your exports. In a bank account, as in a stream ecosystem, the inputs should equal the exports. If they don't, you know that you have some explaining to do!
Exported sodium chloride (NaCl) means how much sodium chloride was measured in the stream, or was "exported" from the watershed. Since the sodium chloride must be coming from somewhere, the researchers wanted to know about all of the possible sources, or inputs, of sodium chloride to the watershed.
We have a unit on salt pollution, which you may wish to complete before using this dataset.
Data Sampling & Compilation
Data Location: Wappinger Creek, Millbrook, NY. Watershed is 91% forested or open field and 9% residential and commercial.
Data Collection Methods: Stream samples were collected each month at the Cary Institute in Millbrook, NY, as near to base flow as possible.
These data were collected through the Cary Institute long-term Environmental Monitoring program. For more information on this program, the data collection methods, and the Wappinger Creek monitoring sites, read the above "expanded metadata and resources" sheet created by teachers Jessica Genter and Miriam Straus.
Data Source: Vicky Kelly, Environmental Monitoring Manager, Cary Institute of Ecosystem Studies. Published in Kelly, et al. 2008. Retention in a rural watershed: legacy effects of road salt on streamwater concentration. Environmental Science & Technology, 42:410-415.