California Drought

Wet Year (2011) vs. Dry Year (2014)

ES 771 Remote Sensing Fall 2014
Kyle Jackson & Calif Tervo

Introduction

Most of California is experiencing “extreme” to “exceptional” drought, the two most severe categories according to the U.S. Drought Monitor. California has had three years of exceptionally low rainfall. The water year runs from October 1 –September 30, and the 2014 year which just ended was the third driest in 119 years of record.

Statewide Precipitation

2011: 30.10”
2012: 16.23”
2013: 17.56”
2014: 12.08”

source - CA Dept. of Water Resources

California is a major producer in the fruit, vegetable, tree nut, and dairy products. The drought will likely raise prices on these products for some time and will likely affect what is produced in the future.

Farmers have been particularly affected and have relied more heavily on stored ground water to get them through the drought. In the Central Valley, the ground water tables have been dropping and farmers are drilling deeper wells. The state is taking many actions to increase conservation efforts. Local water agencies have imposed mandatory restrictions on water use.

This study looks at Landsat images for three locations, Silver City, Spanish Flat, and Santa Cruz Mountains, the positions of which are seen in the California outline map. The study looks at the two years, 2011 and 2014, in an effort to detect the effects of the drought on vegetation. The locations were chosen because they are natural areas that do not rely on irrigation such that the health of the vegetation of primarily dependent upon precipitation. Areas with high natural vegetation were sought. The years were chosen because 2011 is the latest wet year and 2011 was preceded by a fairly wet year.

Two of the locations, Silver City and Spanish Flat, are inland, A coastal location, Santa Cruz Mountains, was chosen to see if the proximity of the Pacific Ocean had an effect. Silver City was the major focus, and more image comparisons were done with respect to that location.

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