Section 37.03.12.025 - RIVER REACHES01.Divisions of the Big Lost River. For the purposes of quantifying river gains, losses, and calculating and accounting for natural flow, the Big Lost River is divided into the reaches identified below. Reference to a specific river reach will be by the name of the downstream station or terminus point. b. Howell Gage to Chilly Bridge located in the NW1/4NE1/4NW1/4, Section 5, Township 8 North, Range 22 East, B.M.c. Chilly Bridge to the 2-B Gage.d. 2-B Gage to Leslie Gage located in the NW1/4SW1/4SE1/4, Section 10, Township 6 North, Range 25 East, B.M.e. Leslie Gage to Moore diversion located in the NW1/4SE1/4SE1/4, Section 4, Township 5 North, Range 26 East, B.M.f. Moore diversion to Arco diversion located in the NW1/4NW1/4NW1/4, Section 26, Township 4 North, Range 26 East, B.M.g. Below Arco diversion to the Arco Gage.02.River Reach Computations. For each reach of the river the natural flow will be computed as the natural flow entering the reach plus gains entering the reach minus losses from the reach. The natural flow thus calculated will be allocated as described in Rule 40.03.Gage Station or Other Flow Measuring Facility. A gage station or other flow measuring facility, as approved by the director, is located at the Howell Gage, Chilly Bridge, 2-B Gage, Leslie Gage, Moore diversion, Arco diversion and Arco Gage. The Howell, 2-B and Arco gages shall be maintained as part of the USGS Cooperative Program, or equivalent measurement program, and operated continuously. Water District 34 shall continue to contribute to the maintenance and operation of these gage sites in the same proportion as is currently contributed. All other gages shall be operated when water diversions, other than solely storage in Mackay Reservoir, are being made from the river. The cost of installation, operation and maintenance of these other measuring facilities is the responsibility of Water District 34.Idaho Admin. Code r. 37.03.12.025