1. Water Resources Issues in the Lower Rio Grande June 3, 2005 J. Phillip King, P.E. Assc. Professor/Assc. Dept. Head Dept. of Civil Engineering, NMSU Consultant, EBID

2. Major LRG Water Issues Drought and Project Water Allocation – Reclamation, EBID, El Paso #1, Mexico Active Water Resource Management (AWRM) alternative administration regulations – OSE, Lower Rio Grande Water Users Organization (LRGWUO) Conversion of surface water to non – agricultural uses in LRG – EBID, Las Cruces, Doña Ana MDWCA, OSE

3. Caballo Conveyance System Irrigated Land Groundwater Drain Flows Atmosphere Seepage Exfiltration Pumping Return Diversion Bypass (spill) Delivery Deep Percolation Storm Flow Bypass (spill) Seepage Release Rio Grande M&I Users Pumping Deep Perc. Discharges Imported Water Exported Water Non-irrigated Land Rio Grande at El Paso Pumping Deep Percolation ET Precip ET Precip Drainage ET Precip Surface Water-Groundwater Interaction in the LRG

4. Water Use by Sector in LRG 97 percent of LRG water use is irrigation or public water systems

5. The Rio Grande Project Water rights appropriated January 23, 1906 90,640 water-righted acres in Elephant Butte Irrigation District (EBID) in New Mexico 69,010 water-righted acres in El Paso County Water Improvement District No. 1 (EPCWID) in Texas 60,000 acre-feet of water for the Republic of Mexico by the Treaty of 1906 Construction largely completed by 1917; drainage system built in 1920s Operated as a single irrigation system by Bureau of Reclamation City of El Paso began treating surface water in 1940s Districts paid off construction costs in late 1970s

6. Current Project Water Allocation BOR allocates water to US districts and Mexico –Based on water available for release storage and actual river efficiency –Mexico gets their water first, and the remainder is divided between EBID and EP#1 proportionately (57%/43%) Districts allot water to farmers based on BOR allocation and system conveyance efficiency

7. Drought Response Conjunctive management of surface water and groundwater –Robust river-connected aquifer used for agriculture, M&I, domestic use –Short surface water supplies prompt increased groundwater withdrawals –Groundwater withdrawals affect river efficiency

8. Rio Grande Project Release and Diversion

9. Motivation for AWRM Manage surface water and groundwater intelligently to maximize beneficial use in New Mexico Maintain hydrologic health of the LRG Protect senior water rights from impairment in the absence of a completed adjudication Protect downstream users in Texas and Mexico from overuse in LRG Provide mechanisms for out-of-priority users to offset impacts on senior and downstream water users

10. Complications Rio Grande Operating Agreement Project authority over surface water, OSE authority over groundwater Lack of clarity in relationship between surface water and groundwater rights Junior basic necessities

11. Current Status of AWRM State-wide regulations finalized Metering order issued for all groundwater diversions in LRG except single domestic wells State is developing draft basin-specific regulations for LRG to be released for review by LRGWUO in May - delayed 2 months LRGWUO directed technical committee to develop alternative administrative plan

12. Foundations for Special Water Users Associations Developed by EBID, City of Las Cruces, and the State Engineer EBID Policy 2003-GA8, approved November 19, 2003 73-10-48 NMSA

13. SWUAs Allow entity to use surface water for M&I and other uses within District boundaries –Ownership of Project Water rights –Lease of Project Water rights –Transfer of Project Water

14. SWUA Details Assessed as EBID constituents Share pro rata in shortages Surface water rights maintain EBID’s 1906 priority date SWUA must lease all of the water from a parcel; land must be fallowed Special Combined Unit: Small tracts (<2 acres) can be consolidated and treated as farm tract for ordering and billing Maintained as Ag use until demand for direct M&I use develops

15. Existing System of Annual Water Transfers Total Allotment Agricultural Users Conservation Pool Agricultural Water Used

16. Structure for Transfers of Water to Special Water Users Associations Total Allotmen t Agricultural Users SWUA Agricultural Pool Municipal Pool Agricultural Water Used Municipal Water (SWTP) Conservation Pool: Leases: Parties Negotiate Price

17. Who Can Form SWUAs? Municipalities Counties State Universities Member-owned community systems Public utilities Interstate Stream Commission

18. Relationship of SWUAs to AWRM SWUAs provide an alternative to strict priority administration –SWUAs allow junior users to move up in seniority/priority –Common priority date among EBID SWUAs and irrigators create pro rata sharing of shortages Market-driven process