Data Files lets you download the dataset in your choice of format. Tables lets you view the data as a table. A number of formatting options are available. We start with a quick reminder of where you are in the collection of datasets. As you go from left to right, the datasets listed get more and more specific, ending with the current dataset, River .
Documents give additional information about the current dataset.
Datasets are collections of variables and datasets. This will become clearer once you look at the outline .