The valley floor itself can experience a variety of topographical changes. As was discussed, the Napa River and other streams deposit clays, shales, and a variety of other river sediments in the valley lowlands, while a historical narrowing of the river has resulted in large concentrations of sedimentary rocks. The Napa River also can flood from late fall to early spring, depositing river sediments far past its typical banks (Larson).

The elevation of the valley also changes as one travels south to north. At the southernmost point of Napa Valley, the elevation is essentially at sea level, but it rises to 362 feet at the northern end, near Calistoga (Larson). The valley also narrows as one moves north, from a width of five miles in Napa to just one mile in Calistoga, where the Mayacamas, Mt. St. Helena and the Vacas close in around it (Larson). The topographical changes across...
[ View Full Essay]