IDWR Administrative Basins

IDWR has divided the state into more than 50 uniquely numbered administrative basins in order to coordinate water management activities. Each basin is assigned to one of the four IDWR regions. NORTHERN REGION:03, 81, 82, 83, 84, 85, 86, 87, 91, 92, 93, 94, 95, 96, 97, 98 WESTERN REGION:02, 03, 51, 55, 57, 61, 63, 65, 67, 69, 77, 78, 79 SOUTHERN REGION: 36, 37, 41, 43, 45, 47, 71, 72 EASTERN REGION: 11, 13, 15, 17, 21, 23, 24, 25, 27, 29, 31, 32, 33, 34, 35, 73, 73, 75