Hydrologic Investigation of the Dry Lake Region in East Central Arizona

Abstract

The Dry Lake Region is located in Navajo County, Arizona, near the southern margin of the Colorado Plateau. The region's internal drainage basin of 160 mi2 is further augmented by 50 mi² of the Phoenix Park Wash drainage. The dominate surface water inflow to the playa is the 12 to 13 MGD of paper pulp mill effluent from Southwest Forest Industries near Snowflake, Arizona. As a result, the playa surface water is now covering several thousand acres. Dry Lake water quality is relatively poor by Arizona Department of Health Services (ADHS) drinking water standards. Ground water in the region is produced from the Coconino Aquifer which is comprised of the Coconino Sandstone and the Kaibab Limestone. The depth to ground water is 400 feet with a saturated zone 100-175 feet thick. Wells in the region yield from 0 to 500 gpm. The presence of the Holbrook Anticline and the Dry Lake Syncline influence both ground water flow direction and artesian conditions. There is concern that the playa may not be suited as an evaporative disposal basin because of the potential influence that karst topography and linear surface features may have on the water balance of the region.