Bay seniors know that not all Napa’s liquid charms are squeezed from grapes. Rivers, small streams and lakes dot the county even in the midst of drought. A sweet place for picnicking, kayaking and fishing is Lake Hennessey, a 1.25 square mile reservoir in the hills east of St. Helena. Water levels appear decently high this year. Bass, blue gill and sunfish are plentifully stocked. No swimming.