The Cuyama Valley, the driest region in Santa Barbara County, is awash in discontent. The world’s largest carrot producers, newly subject to restrictions on over-pumping, are suing all other landowners over water rights, and legal fees are mounting. The Cuyama groundwater basin, which covers 380 square miles east of Santa Maria, overlapping with Kern, San Luis Obispo, and Ventura counties, is on the list of the state’s 21 basins in “critical overdraft.”