Until only recently, the Salinas River had a continuous flow throughout the year, stretching back to at least 1941 (when USGS complete monitoring records in the Salinas area began,) and all of the way up through until 1989. Most probably primarily due to recent increases in agricultural water demand in the Salinas Valley, and the resultant lowering of water tables, the lower reaches of the Salinas river (north of King City) remained entirely dry during the three years 2013 - 2016.
The atypical drought-breaking rains of the winter of 2016/2017 restored the river's flow to its lower northern reaches in January 2017.
In 1769 when the river was first discovered by the Portola expedition, it was reported by them as being a "river watering a luxuriant plain" filled with fish weighing 8 or 10 pounds. As of the end of 2016, the river had been transformed into little more than a dry bedded run-off feature for the majority of its length.
Nonetheless, with sufficiently heavy rains, and on rare occasions, this now normally dry runoff feature is still capable of quickly transforming itself back into a fast flowing river. In rainfall induced flood conditions, it can at times measure over a mile in width. During the 20th century, such flood conditions are reported to have generally occurred approximately once every 3 to 10 years. The last similar flooding event along the river was reported in 1998.
The current most typical dry or zero flow state of the majority of the river may be more the result of human activity than of any recent changes in weather patterns. Rainfall patterns of recent years in the Salinas area have not significantly changed from historical average rainfall patterns (139 year average annual rainfall in Salinas is 13.26 inches per year, average annual rainfall since 2000 is 11.01 inches per year). Recent increases in water use, primarily in the agricultural sector, and the damming of the river and its tributaries may be contributing factors causing the now mostly dry condition of the riverbed.