(1) There is designated a Horse Creek Controlled Groundwater Area. Horse Creek Controlled Groundwater Area (HCCGWA) means an area of approximately 7995 acres or 12 square miles located southwest of Absarokee, Montana, and is generally described as follows:

(a) beginning at intersection of highway S-420 and Lower Grove Creek Road, proceeding southwest along Lower Grove Creek Road to intersection with Grove Creek Road, following Grove Creek Road to bridge over Fishtail Creek, following Fishtail Creek to confluence with West Rosebud Creek, following West Rosebud Creek to Ross-Flannigan Ditch diversion, following Ross-Flannigan Ditch to intermittent tributary to West Rosebud Creek in section 11, following intermittent tributary to its confluence with West Rosebud Creek, following West Rosebud Creek to bridge at highway S-420, following S-420 to starting point;

(b) a map of the area within the HCCGWA is posted on the department's website.

(2) The department shall accept one Notice of Completion of Groundwater Development, Form 602, per parent tract within the HCCGWA if all of the following are met, otherwise an Application for Beneficial Water Use Permit, Form 600 must be filed.

(a) The groundwater development point of diversion is on a parent tract of land. A parent tract means a tract of land as it exists within the HCCGWA on October 27, 2011.

(b) The purpose is for domestic, multiple domestic, lawn and garden (which includes shelterbelts), or stock.

(c) The maximum appropriation is 35 gallons per minute or less.

(d) The volume used per year is not greater than one acre-foot (325,851 gallons) per year.

(e) The project does not include a reservoir.

(3) An Application for Beneficial Water Use Permit, Form 600 must include the following:

(a) a mitigation plan which will offset the rate, timing, and location of depletion calculated within the HCCGWA; and

(b) an Application to Change, Form 606, if the mitigation plan includes changing an existing water right for mitigation purposes.

(4) The department may also accept the following within the HCCGWA:

(a) Application to Change, Form 606;

(b) Replacement Well Notice, Form 634; or

(c) Redundant Well Construction Notice, Form 635.

(5) All new wells, whether a new appropriation or change of existing appropriation, must install a 0.75-inch access tube (preferably PVC) to within five feet above the pump to allow static water level measurements to be taken.

(a) The appropriator shall measure the static water level quarterly and record it on a form provided by the department.

(b) Records must be submitted to the department annually.

(6) All new wells shall have a department-approved in-line meter installed at a point approved by the department to measure the total volume of water diverted.

(a) Water must not be diverted until the required measuring device is in place and operating.

(b) Water use records shall be submitted annually to the department.

(7) Water use for lawn and garden irrigation under all water rights issued after the effective date of this rule that do not have mitigation will be discontinued when the 90-day standard precipitation index (SPI) is less than or equal to -1.

(a) The 90-day SPI will be taken at the center of section 15, T4S, R18E, from the Upper Missouri River Basin (UMRB) Drought Indicators Dashboard.

(b) The department will post on the department's website the 90-day SPI and the link to the UMRB website at the beginning of each of the irrigation season months of May, June, July, August, and September. 

(8) The department may, if circumstances change, propose to amend these rules accordingly after public notice and hearing.