(a) General.

1. (1) In determining prior rights to groundwater the Board shall make use of all data available to it.
2. (2) Such data shall include, but shall not be limited to, the names and last known mailing address of all applicants or claimants for the use of groundwater of record with the Board, including application number and date thereof, the legal description of the location of the well or wells and place of use, the quantity of water applied for or claimed in gallons or acre-feet per year, purposes of use, and amount of water actually put to beneficial use each year.
3. (3) Such information shall be compiled and made a matter of record in the office of the Board.

(b) Tentative order of prior groundwater rights.

1. (1) As soon as data on any county has been compiled, the Board shall make an order listing the applicants or claimants who, in the Board's opinion from the information then available to it, are holders of prior water rights to use groundwater by virtue of the bases described in 785:30-11-1(c).
2. (2) Said order shall set out the priority date, place of well(s), parcel of land upon which the prior right was established, and the purpose and amount of water proposed to be determined for each applicant or claimant in the county.
3. (3) This order shall be plainly marked "Tentative Order Recognizing Prior Rights in…County."
4. (4) The tentative order shall be an alphabetical listing of each applicant and claimant known to the Board.
5. (5) The tentative order shall include the amount of groundwater the Board determines the applicant or claimant has established as a prior right, the purpose of the prior right, the location of the well or wells, and the legal description of the land on which the prior right was perfected.
6. (6) A subsection shall be included in the tentative order listing all applicants and claimants who, according to information on file at the Oklahoma Water Resources Board, did not perfect a prior right at the time the tentative order was prepared as determined by the Board.

7. (7) In determining the amount of groundwater used by an applicant or claimant to set out in the prior rights order, the Board shall use the following information and presumptions absent specific evidence to the contrary:

   1. (A) When the amount of water is reported by number of inches over number of acres, the water will be calculated as such.
   2. (B) Where the amount of water is reported by number of acres times the number of applications, each application will be computed as four (4) inches up to six (6) applications, three (3) inches per application from seven (7) to ten (10) applications; two (2) inches per application from eleven (11) to fifteen (15) applications; and one (1) inch per application when more than sixteen applications are applied.
   3. (C) Where there is evidence that groundwater was put to beneficial use, however the number of inches applied or the number of applications is not known, the Board will consider one (1) application or four (4) inches was applied when the tentative order is prepared provided the number of acres irrigated is known.
8. (8) Where an application was filed for two (2) acre-feet per year when the intention was to file for two (2) acre-feet per acre per year, the Board will consider the application to be for two (2) acre-feet per acre per year.

9. (9) The following standards have been established in order to determine prior groundwater rights:

   1. (A) When based upon making application to the Board prior to July 1, 1973, the amount of groundwater actually taken and placed to beneficial use will be calculated to the last day of the second or fifth year.

   2. (B) When based upon taking and using groundwater without an application to the Board prior to July 5, 1961, the priority date will be the last day of the year when the date of first beneficial use is known only to that year, and the amount of water actually taken and placed to beneficial use will be calculated to the last day of the fifth year. If a crop was reported as having been irrigated the year of first beneficial use, the priority date will be established the first day of the growing season for that crop. The following dates shall be considered as the beginning of the respective growing season:

      1. (i) Winter Wheat–September 1
      2. (ii) Sorghum–May 1
      3. (iii) Cotton–May 1
      4. (iv) Corn–April 1
      5. (v) Maize–April 1
      6. (vi) Alfalfa–March 15
      7. (vii) Pasture–March 15
   3. (C) Where more land was irrigated than was requested by the application prior to July 5, 1961, and there is no indication that the extra land is owned or leased by the applicant, the water will be split according to the amount of water applied to the excess acres in order to perfect the second prior right.

(d) Published notice by newspaper of hearing on tentative order.

1. (1) The Board shall also give notice of such hearing by publication in a newspaper of general circulation in each county in which prior rights to groundwater are to be determined in the proceedings, once a week for two (2) consecutive weeks prior to the hearing; and the last notice shall be published at least thirty (30) days prior to the date set for the hearing.
2. (2) The published notice shall contain the date and place of the hearing together with a general description of the location in which prior rights to the beneficial use of ground water are to be determined and the address to which requests for a copy of the tentative order may be sent.

(f) Appearance at hearing.

1. (1) Any person claiming a prior right to the beneficial use of groundwater within the area for which prior rights are to be determined may appear at the hearing in person or be represented by legal counsel.
2. (2) For an applicant or claimant to submit evidence in support of the amount of groundwater use unknown to the Board, said individual must sign a sworn statement setting out the amount of groundwater used each year.

(g) Impairment of rights. Any party may present evidence in support of or opposition to the tentative order of prior rights to ground water under consideration at the hearing and shall file at the hearing, or to the Board at its office prior to the hearing, the following:

1. (1) The name and post office address of the applicant or claimant.
2. (2) The location of the well or wells to which the claim relates.
3. (3) The amount of water claimed or disputed.
4. (4) The purpose for use of the water claimed or disputed and the place of its use.
5. (5) The dates of applications, if any, and the dates of beneficial uses made.
6. (6) A description of the land irrigated if the claim or contested claim relates to irrigation, together with a designation of the number of irrigable acres in each forty (40) acre tract or fractional part thereof.
7. (7) The population served by the amount of the claim if the claim or contest relates to municipal use.
8. (8) The type or kind of industrial use if the claim or contest relates to such use.
9. (9) Any additional information the Board may require.

(h) Tentative order hearing.

1. (1) At the hearing the Board shall hear the evidence of any person interested party.
2. (2) The hearing record will be left open for sixty (60) days from the hearing date to insure every party the opportunity to submit additional evidence concerning groundwater put to beneficial use under the requirements of the groundwater laws prior to July 1, 1973.
3. (3) All such evidence shall be considered by the Board in its determination of prior rights to the beneficial use of groundwater.

(j) Service of final notice. Service of such final notice shall be deemed completed:

1. (1) Upon depositing a copy of such final order in the post office as registered or certified mail addressed to each applicant, claimant, and contestant whose name and address is known to the Board; and
2. (2) Upon the filing of two (2) or more copies of the final order in the office of the county clerk of each county in which prior rights were determined by the order.