DRAFT MEMORANDUM TO FILE

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1 DRAFT MEMORANDUM TO FILE From: Tom Gooch, P.E., and Stephanie Griffin, P.E. Date: September 19, 23 [NTD2182] T:\Task 2 - Population and Water Needs Projections\Non-Municipal Water Demand Projections\draft irrigation memo.doc Project: NTD-2182, Region C 26 Regional Water Plan Subject: Region C Irrigation Water Use Projections This memorandum discusses recommended changes to the Texas Water Development Board s draft projections of irrigation water needs. The memorandum includes an introduction to the recommended irrigation water needs projections for Region C and discussions of historical growth trends in Region C, the methodology of the projections, recommendations for irrigation water needs projections, and the impact of the recommended changes from the initial TWDB values. The appendix to this memorandum includes tables and figures showing historical and projected irrigation water needs for Region C. INTRODUCTION The Region C Water Planning Group received the Texas Water Development Board s (TWDB) initial Region C demand projections in January 23. The Planning Group and its consultants have reviewed the draft projections for irrigation water needs and offer the comments included in this memorandum. The TWDB allows the regions to make adjustments to the projected irrigation water needs based on any of the following reasons: Evidence that another year ( ) would be more representative of irrigation demands Evidence that irrigation estimates from another source are more accurate that those provided by the TWDB Evidence that the expectation of conditions are such that the projected annual rates of change for irrigation water needs used in the 22 State Water Plan are no longer valid. HISTORICAL AND PROJECTED GROWTH TRENDS IN REGION C Irrigation water needs are much lower in Region C than other water uses. However, these water needs are important when determining the total water needs projections for the region over the next 5 years. We analyzed the historical water use for irrigation by county beginning in 199 through 2.

2 Memo to File from Tom Gooch, P.E., and Stephanie Griffin, P.E. Region C Irrigation Water Use Projections September 19, 23 Page 2 of 4 DESCRIPTION OF TWDB DATA The TWDB established the base year for water use to be the year 2. The TWDB used the information obtained in their year 2 Irrigation Survey conducted by the Natural Resources Conservation Service. The rate of change from the base year into future decades remained the same as what was used in the 22 State Water Plan. REVIEW METHODOLOGY One focus of the Region C review of the TWDB Draft Water Usage Projections was to assimilate as much information as possible from the local water users. Questionnaires were mailed to County Agricultural Extension Agents to gain input on their knowledge of water usage trends in their area. A total of 16 questionnaires were mailed and 12 responses were received. Questionnaires were also mailed to County Judges, but we received fewer responses from those representatives. In the event that additional information was necessary following a survey response, the entity received a follow up call from the Planning Group to clarify the comments and to solicit more detailed information. The Planning Group also reviewed the historical data provided by the TWDB. Where historical data appeared to be questionable, basic data was sought to confirm or correct the information. Survey responses and a general knowledge of past weather conditions were helpful in identifying any inconsistencies. From the historical data, trends in water usage were identified and analyzed. The data obtained from the questionnaires was combined with historical trends and a general knowledge of growth trends to develop an initial set of irrigation water needs projections. Individual graphs of each county were plotted to compare historical data, TWDB SB1 Phase 1 projections and the draft TWDB SB1 Phase 2 projections. Each county was reviewed. The graphs for each county are shown in Appendix A of this memorandum. METHODOLOGY FOR REGION C RECOMMENDATIONS FOR IRRIGATION WATER NEEDS Collin County The draft TWDB irrigation water needs projections for Collin County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time.

3 Memo to File from Tom Gooch, P.E., and Stephanie Griffin, P.E. Region C Irrigation Water Use Projections September 19, 23 Page 3 of 4 Cooke County The draft TWDB projections are zero for Cooke County. We believe that zero is not the best projection based on the 444 acre-feet per year usage from 1996 through Cooke County has a history of irrigation water demand and we do not believe we should assume that it will remain zero throughout the planning period. We recommend changing the year 21 water use to 444 acre-feet per year and keeping that demand constant through 26. Dallas County The draft TWDB irrigation water needs projections for Dallas County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time. Denton County The draft TWDB irrigation water needs projections for Denton County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time. Ellis County The draft TWDB irrigation water needs projections for Ellis County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time. Fannin County The draft TWDB water use of 4,68 acre-feet per year in Fannin County for the year 2 is a reasonable irrigation water demand. However, the draft TWDB projections in Fannin County are reduced over time. We believe the irrigation water demand should remain constant at 4,68 acre-feet per year though 26. Freestone County The draft TWDB irrigation water needs projections for Freestone County appear to be appropriate. We do not recommend any adjustments. Grayson County The draft TWDB irrigation water needs projections for Grayson County appear to be appropriate. We do not recommend any adjustments. Henderson County (Trinity Basin) The draft TWDB irrigation water needs projections for Henderson County appear to be appropriate. We do not recommend any adjustments.

4 Memo to File from Tom Gooch, P.E., and Stephanie Griffin, P.E. Region C Irrigation Water Use Projections September 19, 23 Page 4 of 4 Jack County The draft TWDB irrigation water needs projections for Jack County appear to be appropriate. We do not recommend any adjustments. Kaufman County The draft TWDB water use of 2,916 acre-feet per year in Kaufman County for the year 2 is a reasonable irrigation water demand. However, the draft TWDB projections in Fannin County are reduced over time. We believe the irrigation water demand should remain constant at 2,916 acre-feet per year though 26. Navarro County The draft TWDB irrigation water needs projections for Navarro County appear to be appropriate. We do not recommend any adjustments. Parker County The draft TWDB irrigation water needs projections for Parker County appear to be appropriate. We do not recommend any adjustments. Rockwall County The draft TWDB irrigation water needs projections for Rockwall County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time. Tarrant County The draft TWDB irrigation water needs projections for Tarrant County appear to be appropriate. We do not recommend any adjustments. The significant increase in irrigation demand in 2 is due to golf course irrigation being reported as irrigation water use for the first time. Wise County The draft TWDB irrigation water needs projections for Wise County appear to be appropriate. We do not recommend any adjustments.

5 APPENDIX A

6 Table 1 Draft TWDB Irrigation Water Needs Projections County Use (Ac-Ft/Yr) Projected Water Needs (Ac-Ft/Yr) Collin 2,995 2,995 2,995 2,995 2,995 2,995 2,995 Cooke Dallas 13,87 13,87 13,87 13,87 13,87 13,87 13,87 Denton 2,18 2,18 2,18 2,18 2,18 2,18 2,18 Ellis Fannin 4,68 4,24 3,899 3,589 3,32 3,38 2,796 Freestone Grayson 3,382 3,561 3,751 3,95 4,158 4,381 4,616 Henderson Jack Kaufman 2,916 2,839 2,762 2,689 2,616 2,547 2,48 Navarro Parker Rockwall 1,125 1,125 1,125 1,125 1,125 1,125 1,125 Tarrant 8,417 8,417 8,417 8,417 8,417 8,417 8,417 Wise Total 4,153 39,887 39,659 39,475 39,323 39,213 39,139 A-1

7 Table 2 Region C Recommended Irrigation Water Needs Projections County Use (Ac-Ft/Yr) Projected Water Needs (Ac-Ft/Yr) Collin 2,995 2,995 2,995 2,995 2,995 2,995 2,995 Cooke Dallas 13,87 13,87 13,87 13,87 13,87 13,87 13,87 Denton 2,18 2,18 2,18 2,18 2,18 2,18 2,18 Ellis Fannin 4,68 4,68 4,68 4,68 4,68 4,68 4,68 Freestone Grayson 3,382 3,561 3,751 3,95 4,158 4,381 4,616 Henderson Jack Kaufman 2,916 2,916 2,916 2,916 2,916 2,916 2,916 Navarro Parker Rockwall 1,125 1,125 1,125 1,125 1,125 1,125 1,125 Tarrant 8,417 8,417 8,417 8,417 8,417 8,417 8,417 Wise Total 4,153 4,776 4,966 41,165 41,373 41,596 41,831 A-2

8 Table 3 Difference in Irrigation Water Needs Projections County Use (Ac-Ft/Yr) Projected Water Needs (Ac-Ft/Yr) Collin Cooke Dallas Denton Ellis Fannin ,19 1,36 1,57 1,812 Freestone Grayson Henderson Jack Kaufman Navarro Parker Rockwall Tarrant Wise Total 889 1,37 1,69 2,5 2,383 2,692 A-3

9 and Projected Irrigation Demands for Collin County 3,5 3, 2,5 2, 1,5 SB1, Phase 1 1,

10 and Projected Irrigation Demands for Cooke County 1,2 1, TWDB SB1, Phase 1 RCWPG Recommended

11 and Projected Irrigation Demands for Dallas County 14, 12, 1, 8, 6, TWDB SB1, Phase 1 4, 2,

12 and Projected Irrigation Demands for Denton County 2,5 2, 1,5 1,

13 and Projected Irrigation Demands for Ellis County

14 and Projected Irrigation Demands for Fannin County 16, 14, 12, 1, 8, 6, RCWPG Recommended 4, 2,

15 and Projected Irrigation Demands for Freestone County

16 and Projected Irrigation Demands for Grayson County 6, 5, 4, 3, 2, 1,

17 and Projected Irrigation Demands for Henderson County

18 and Projected Irrigation Demands for Jack County

19 and Projected Irrigation Demands for Kaufman County 3,5 3, 2,5 2, 1,5 RCWPG Recommended 1,

20 and Projected Irrigation Demands for Navarro County

21 and Projected Irrigation Demands for Parker County 2, 1,8 1,6 1,4 1,2 1,

22 and Projected Irrigation Demands for Rockwall County 1,2 1,

23 and Projected Irrigation Demands for Tarrant County 9, 8, 7, 6, 5, 4, 3, 2, 1,

24 and Projected Irrigation Demands for Wise County 1,6 1,4 1,2 1,

25 Irrigation Demand Projections for Region C 45, 4, 35, 3, 25, 2, 15, RCWPG Recommended 1, 5,