Conjunctive Water Resource Management Technical Data Report-Volume I

Colorado

Prepared for the New Mexico/Texas Water Commission

June 1994

BOI,ILE Engineering-Science, Inc. Conjunctive Water Resource Management and Aquifer Restoration Study for New Mexico/Texas Water Commission

Revised - 1116/95 Table of Contents

Executive Summary ...... 1 Introduction ...... 7 Purpose of the Study ...... 7 Study Area ...... 7 Historic Perspective ...... 7 EI Paso's Water Supply ...... 9 Subject of the Study for Phases II and m...... 12 General Methods Applied ...... 13 Approach ...... 14 Data Collection ...... 15 Base Map ...... 15 Water Budget ...... 15 Water Demand ...... 18 Conveyance, Treatment and Distribution ...... 18 Alternative Objectives ...... 19 Alternative Objective 1 ...... 19 Alternative Objective 2 ...... 19 Alternative Objective 2a ...... 20 Alternative Objective 3 ...... 22 Physical Attributes of Conceptual Alternatives ...... 22 Capital Cost Estimates ...... , ...... 42 Water Conveyance Costs ...... 50 Regional Water Treatment Plants ...... 54 Rio Grande Project Water Supply...... 54 Future Population and Water Demand ...... 54 Estimation of Ultimate Demand ...... 60 Treatment Processes ...... 61 Raw Water Quality ...... 62 Treatment Water Quality Goals ...... 64 Regulatory Objectives ...... 64 Policy Objectives ...... 70 Process Selection ...... 71 Estimation of Treated Storage Capacity ...... 72 Distribution System Development ...... '" 72 Las Cruces Regional Treatment Plant and Distribution System ...... 72 Phased Development Plan for Las Cruces ...... 78 Anthony Regional Treatment Plant and Distribution System84 Distribution System ...... 86 Phased Development Plan for Anthony ...... 88 Water Budget Analysis ...... 96 Introduction ...... 96 Methodology ...... 97 Results ...... 101 Additional Considerations ...... 113 Canal and Drain Storage ...... 113 Return Flow Treatment ...... 117 Aquifer Storage and Recovery ...... 119 Drought Contingency ...... 122 Environmental Considerations ...... 124 Swnmary of Study Results ...... 126 Alternative Objective No.1 ...... 128 Alternative Objective No.2 ...... 128 Alternative Objective No.3 ...... 129 Costs ...... 130 Water Budget Analysis ...... 131 Surface Water Loss Evaluation ...... 135 Summary of Aquifer Effects ...... ,. 135 List of References ...... 142 Technical Appendices ...... 145 A. Study Criteria Memorandum ...... 145 B. Cost Memorandum ...... 145 C. Calculations ...... 145 D. Water Budget Spreadsheet ...... 153 List of Figures

1 Hueco Basin Aquifer Depletion 2 Canal Cross Section for Alternative 1 3 Routesfor Alternatives 1, 2, and 3 4 Typical Siphon River Crossing 5 Typical Check Structure 6 Typical Check Structure Sections 7 Typical Turnout 8 Typical Turnout Sections 9 Alternative 1 Flow Diagram for Year 2005 10 Alternative I Flow Diagram for Year 2015 11 Alternative 1 Flow Diagram for Year 2035 12 Canal Cross Section for Alternative 2 13 Alternative 2 Flow Diagram for Year 2005 14 Alternative 2 Flow Diagram for Year 2015 15 Alternative 2 Flow Diagram for Year 2035 16 Dual Canal Section for Alternative 2a 17 Alternative 2a Flow Diagram for Year 2005 18 Alternative 2a Flow Diagram for Year 2015 19 Alternative 2a Flow Diagram for Year 2035 20 Alternative 3 Flow Diagram for Year 2005 21 Alternative 3 Flow Diagram for Year 2015 22 Alternative 3 Flow Diagram for Year 2035 23 Las Cruces Water Treatment Plant Region 24 AnthonyTreatment Plant Region 25 Dona Ana County Census Division 26 Treatment Plant Process Flow Diagram 27 Las Cruces Water Treatment Plant Treated Reservoir Service areas 28 Las Cruces Water Treatment Plant and 2015 Distribution System 29 Las Cruces Water Treatment Plant and 2005 Distribution System

------30 Las Cruces Water Treatment PIant and Ultimate 2035 System 31 Las Cruces Water Treatment Plant and Ultimate Distribution System 32 Anthony Water Treatment PIant Treated Reservoir Service Areas 33 Anthony Water Treatment Plant and 2015 Distribution System 34 Anthony Water Treatment Plant and 2005 Distribution System 35 Anthony Water Treatment Plant and 2035 Distribution System 36 Anthony Water Treatment PIant and Ultimate Distribution System 37 Water Budget - Baseline 38 Total Dissolved Solids (TOS) Mass Budget - Baseline 39 Water Budget - Alternative 1 40 Total Dissolved Solids (TOS) Mass Budget - Alternative 1 41 Water Budget - Alternative 2 42 Total Dissolved Solids (TOS) Mass Budget - Alternative 2 43 Water Budget - Alternative 3 44 Total Dissolved Solids (TOS) Mass Budget - Alternative 3 45 Regulating Storage Reservoirs 46 Service Fields of Alternatives 47 Mesilla Basin Loss Rate vs. Time 48 Hueco Basin Loss Rate vs. Time Tables

I Capital Cost for Alternative I 2 Capital Cost for Alternative 2 3 Capital Cost for Alternative 2a 4 Capital Cost for Alternative 3 5 Water Conveyance Unit Cost 6 Annual Water Conveyance Cost 7 Mesilla Valley Population, New Mexico 8 Mesilla Valley Population, Texas 9 Water Treatment Plant Region Populations 10 Mesilla Valley Projected Daily per Capita Water Use II Regional Water Treatment Plant Capacities 12 Water Quality in Caballo Reservoir Releases 13 Current and Expected SDWA Requirements 14 Average and Maximum Daily Demands for Las Cruces 15 Construction Cost for Las Cruces, 2015 16 Construction Cost for Las Cruces, 2035 17 Average and Maximum Daily Demands for Anthony Plant 18 Construction Costs for Anthony, 2015 19 Construction Costs for Anthony, 2035 20 Regulatory Reservoirs Description 21 Capital and Conveyance Cost 22 Water Treatment Plant Costs 23 Water Budget Sununary 24 Mass Budget Sununary 25 River Flow and Quality at Key Locations 26 Surface Water Loss Analysis for Average Year Acronyms and Definitions

af - acre feet af/yr - acre feet per year AquiferlBasinlBolson used interchangeably acequias - irrigation canals, laterals, ditches. cfs - cubic feet per second New Mexicoffexas Water Commission (Commission) EBID - Elephant Butte Irrigation District EDR - Electric Dialysis Reversal EPCWID# I - EI Paso County Water Improvement District No. 1 EPWU - EI Paso Water UtilitiesJPublic Service Board gpcd - gallons per capita per day mwc - International Boundary and Water Commission M&I - Municipal and Industrial mCilday - micro-Couries per day MCL - maximum contaminant level MCLg - maximum contaminant level goal MG - million gallons mg/L - milligrams per liter MGD - million gallons per day . NTU - nephelometric turbidity unit RGP - Rio Grande Project RO - Reverse Osmosis SDWA - Safe Drinking Water Act TDS - total dissolved solids TOe - total organic carbon USBR - United States Department of the Interior, Bureau of Reclamation USGS - United States Geologic Survey WTP - Water Treatment Plant

------Executive Summary

I This report describes progress to date on an effort by the 2 New Mexico-Texas Water Commission (Commission) to 3 improve use ofwater resources in the Rio Grande Project -4 area. The history ofwater resource development is 5 discussed and the basic philosophy ofthe Commission, 6 "conjunctive or complementary use ofboth surface and 7 ground water for the region-wide needs, " is described The 8 recognition that the two major ground water aquifers ofthe -9 region, the Hueco and Mesilla Basins, are finite and 10 depletable resources is an important part ofthe motivation .JI for optimizing conjunctive use. Current over pumping, [2 particularly ofthe Hueco Basin, is rapidly depleting these I3 aquifers, which are an essential element ofthe "'l4 environmental quality ofthe Region.

15 The Commission recognizes that the best solution to the .6 water resource problems ofthe Region is to optimize the use 17 ofrenewable surface water. In order to assist in the -18 implementation ofthis solution, several alternative 9 objectives for a surface water conveyance have been 20 identified A sUrface water conveyance will allow year round delivery to municipal and industrial(M&1) users. It will also L2 preserve the raw water quality which exists in the Rio ...::1.3 Grande Project reservoirs in deliveries to both agricultural 4 and M&I users. 1 Three conveyance alternatives have been identified. These 2 differing conveyances are "alternative objectives" because 3 they do not serve all ofthe same end users and, therefore, 4 do not accomplish the same objective. The Commission has 5 directed its engineering consultants to do a reconnaissance 6 level study ofthese alternatives which are described below:

7 [J Alternative 1- will convey the Rio Grande 8 Project surface water allocation ofthe Texas -9 and Mexican entities and a small amount for 10 M&I uses in Southern Dona Ana County, from 11 the Percha Diversion Dam, along the Rio 12 Grande in a lined canal, without commingling 13 with other irrigation or storm water, to the -14 American Dam in El Paso.

15 [J Alternative 2 - will convey all ofthe surface 46 water allocation ofthe Rio Grande Project from 17 the Percha Diversion Dam in lined and -18 upgraded canals to the American Dam in El 9 Paso. All historic irrigation supplies would be 20 served by diversion from the canal with an option to re-divert instream flows in the Rio Grande for blending with water that has been diverted from the canal. Additionally, provisions would accommodate two new diversions from the upgraded canal to supply surface water to two new regional water treatment plants for distribution to M&! users.

CJ Alternative 3 - will divert the surface water allocation attributable to the EPWU and the Republic ofMexico from the outlet works of Caballo Dam through a closed conduit to a termination at the Jonathan Rogers Water - ! Treatment Plant located near the Riverside

2 1 Diversion Dam in El Paso. Provisions will be 2 made to divert flows at a point between the 3 communities ofAnthony and Canutillo, Texas, 4 to serve a future water treatment plant. 5 Provisions will also be made to divert flows at 6 the Robertson-Umbenhauer Water Treatment 7 Plant in EI Paso.

8 The purpose ofthis study is to provide information to assist 9 the Commission in deciding on a common objective. In 10 addition to the three conveyance objectives outlined above, -II the study will consider other factors which might influence 12 construction and operation ofa successful conveyance 13 project. These factors include:

14 layouts for two regional water treatment plants, consideration ofpossible means for blending the conveyance supply with agricultural return flows and storm water runoff,

18 locations for and benefits ofcanal and drain -19 storage,

20 consideration ofagricultural return flow -21 treatment, initial consideration ofaquifer storage and recovery,

24 consideration ofdrought contingency,

25 consideration ofmeans to improve the regional 26 aquatic and riparian environment and 27 recreational opportunities as part ofproject 28 implementation.

3 I The study also included a water budget analysis for each 2 alternative. These analyses provide the Commission an 3 indication ofthe water quality and quantity changes which 4 would result from implementation ofthe three conveyance 5 alternatives. The water budget model also provides a useful 6 tool for the conceptualization and discussion ofthe - 7 numerous hydrologic and operational factors involved

8 Layouts ofthe three conveyance alternatives are shown on 9 Figure 3 in the map pocket at the back ofthe report. Details 10 ofvarious proposed canal structures are shown in Figures 4 _11 through 8 in the "Alternative Objectives" section. The 12 capital costs ofthe three alternatives, as well as alternative 13 2a, which would allow blending, are as follows:

14 o Alternative 1 - $332 - million o Alternative 2 - $377 - million

16 o Alternative 2a - $541 million

17 o Alternative 3 - $398 million

-18 All ofthe costs presented in this report are estimatedfor the 19 year 2000, as discussed in the Cost Criteria Memorandum 20 in Appendix B. Further detail on alternative costs is 21 included in Tables 1 through 4 in the "Alternative 22 Objectives" and in the cost tabulations in the Summary of -23 Study Results section ofthe report.

24 Layouts ofthe Regional Water Treatment Plants are shown -25 in Figure 23 and Figure 24. Thejirst regional plant is 26 located south ofDona Ana, near Las Cruces and would _27 serve down to Santo Tomas. The second is located between 28 Anthony and Canutillo, Texas and would serve Southern 29 Dona Ana County and the west side ofEI Paso. It would also -30 provide 54 MGD oftreatment capacity for possible use by

4 1 Ciudad Juarez, Mexico. Estimated capital costs ofthese 2 plants and associated treated water transmission facilities 3 are as follows:

4 D Las Cruces Plantfacilitiesfor 2015 demand­ 5 $]30 million

6 D Las Cruces Plantfacilitiesfor 2035 demand­ 7 $242 million

8 o Anthony Plant facilities for 2015 - $310 million

9 o Anthony Plantfacilitiesfor 2035 demand - $466 10 million

11 These costs are based on the uninjlatedfigure for 12 construction costs of$1.15 per gallon per day oftreatment 13 plant capacity in the Cost Basis Memorandum. The -14 treatment plant processes chosen as appropriate for the 15 water quality expectedfrom Caballo Reservoir are shown in 16 Figure 26. Lime softening and carbon adsorption will not be 17 necessary. The construction cost figure used is based on the 18 Jonathan W Rogers Water Treatment Plant, which includes -19 both ofthese processes. Therefore, these estimates ofwater 20 treatment plant construction costs are conservatively high. -21 The final section, "Summary ofStudy Results, " pulls 22 together the important aspects ofthe alternative conveyance --23 objectives to assist the Commission in selecting the common 24 objective with the greatest net benefit to all parties 25 concerned. Costs, surface water quality impacts, pros and 26 cons, and impacts on the sustainability ofthe Hueco and 27 Mesilla Basins are all considered. In keeping with the -28 philosophy ofthe Commission to protect these aquifers, the 29 effect ofthe alternatives on net aquifer balance may be one 30 ofthe most important considerations. All ofthe alternatives 31 greatly improve on the consequences ofthe baseline (no

5 1 action) condition, which provides major support to the 2 viability ofthe surface water conveyance concept.

3 The findings ofthe Phase II/III study are numerous; 4 however, five issues are revealed which will greatly affect 5 the selection by the Commission ofthe preferred 6 alternatives:

7 1. The Hueco Basin is in serious jeopardy of 8 continued depletion which will not be 9 eliminated by any ofthe alternatives. Additional 10 measures will be required.

11 2. Restoration ofthe Hueco Basin requires 12 stabilization ofpumping withdrawals by both El 13 Paso and Juarez and implementation ofaquifer 14 storage and recovery program.

15 3. Aquifer storage and recovery is key to 16 economical sizing and operation ofregional 17 water treatment plants because most summer 18 peak demands can be met from ground water -19 without depletion ofthe aquifer.

20 4. Under all ofthe alternatives, there will be -21 significant deficits in supply from surface water 22 sources unless there is reuse of return flows by 23 rediversion .

24 5. Creative use of return flows could offer not only 25 the possibility ofaugmenting the canal supply 26 but also an opportunity for providing positive 27 environmental benefits through enhancement of L8 riparian habitat and recreational opportunities.

6 Introduction

1 Purpose of the Study

2 During the hundreds of years that man has inhabited the Rio Grande Valley, 3 social and economic changes have altered water demand patterns in the region. 4 However, water suppliers have been reluctant to change the source and 5 distribution of the water due to the high costs and relative permanence of 6 water supply facilities.

7 The purpose of this study is to evaluate the total water resources available to 8 supply the needs of the population in the study area to the year 2035. Further, 9 the study aims to remedy current imbalances of resource distribution which 10 are consuming the ground water element of the total supply beyond its 11 sustainable capacity.

12 Study Area

13 The study region encompasses the Rio Grande floodway starting upstream 14 near Truth or Consequences, New Mexico, and extending southeasterly to 15 Fort Quitman, Texas, located on the international boundary with the Republic 16 of Mexico. This area includes three major cities: Las Cruces, New Mexico; EI 17 Paso, Texas; and Ciudad Juarez, Chihuahua, Mexico. There are numerous 18 small farming communities throughout the valley in this area, and one Indian 19 Pueblo-Ysleta, Texas. Recently, extemporaneous small communities called 20 "Colonias" are being constructed without planning, municipal services, or 21 zoning and subdivision restrictions.

22 Historic Perspective 23 The development of water resources in the region that is now defined by the - 24 Rio Grande Project has a history dating back to the pre-Columbian period. 25 During the Spanish Colonial period, the Camino Real trade route developed 26 between the cities of Chihuahua and Santa Fe through El Paso. The Texas - 27 Republic was established in 1836, followed by the Mexican-American War of 28 1846-1848. The war ended with the Treaty of Guadalupe Hidalgo by which 29 Mexico ceded a large area of the Southwest to the United States, including the -30 New Mexico Territory. In 1853, the United States and Mexico executed the 31 Gadsden Treaty that purchased lands for the United States along the frontier 32 that established the current international boundary. 33 Before the annexation of the project area into the United States, agriculture 34 thrived in the valley floodway of the Rio Grande. Aboriginal Indians -35 inhabiting pueblos along the waterway were the first farmers in the region, 36 followed by the Spanish colonists who introduced advanced European

7 1 irrigation methods involving a network of acequias (community irrigation 2 ditches) to distribute the intennittent flows of the Rio Grande (and other 3 streams) to the lands in the valley floor.

4 With the change of sovereignty of the region, American colonization took 5 place. This influx of settlers was fed first by the establishment of the Santa Fe 6 Trail from Missouri, and later in the nineteenth century by the Butterfield 7 Stage line through Texas and New Mexico, via El Paso. The railroads 8 followed, with both the Southern Pacific and the Santa Fe serving the region. 9 Increased accessibility fostered further development, most notably 10 international commerce with Mexico at El Paso, agriculture in the fertile -11 valleys, and mining in the mountains. 12 The Rio Grande valley floor was characterized by a shallow water table. -13 Phreatophytic vegetation such as Tamarisk (Salt Cedar) and Cottonwood trees 14 thrived in the area. Crop watering was accomplished by diverting the 15 intennittent flows of the Rio Grande through the acequia system, by pumping -16 from shallow wells, and from natural rainfall. The high desert climate at these 17 latitudes provided a relatively long growing season with a sub-freezing 18 dormant period each year.

19 The Rio Grande Project

-20 The Reclamation Act of June 17, 1902, addressed the settlement of the West 21 and the national concern over the use of America's resources. The Rio Grande 22 Project was one of the original projects authorized by Congress on February -23 25, 1905, and by the Secretary of the Interior on December 2, 1905 to develop 24 water resources in the Rio Grande Valley. The construction of Elephant Butte 25 Dam and Reservoir, keystones to the development of the Rio Grande Project, -26 was completed in 1916. Downstream of the dam, this project extended through 27 two states and encompassed over 230,000 acres. The project was composed of 28 river diversion dams, conveyance canals, drain ditches, distribution laterals -29 which generally followed the old community ditches, river levees, and channel 30 improvements along the Rio Grande. A few years later, the Reclamation Act 31 of June 12, 1906, extended to the State of Texas the benefits of the Act of -32 June 17, 1902.

33 The Republic of Mexico was included as a beneficiary of the Rio Grande _34 Project by the Convention of 1906. Mexico has an entitlement of60,000 afJyr 35 in a normal year's allocation. This water is now delivered to the International 36 Dam at Ciudad Juarez, where it is diverted into the heading of the Acequia _37 Madre for agricultural use.

8 1 The Reclamation Act of March 4,1907, appropriated $1 million toward the 2 construction of a dam (Elephant Butte) to store water and to deliver the 3 60,000 af per year to the Republic of Mexico.

4 Before the Rio Grande Project improvements, flows in the Rio Grande were 5 entirely dependent upon the spring snow-melt in the high mountains of 6 Northern New Mexico and Southern Colorado. Old community ditches 7 (acequias) were used to deliver water to the fields. The river was often dry for 8 long periods most years. The municipalities in the region developed 9 community water supply systems by tapping the ground water aquifers with 10 wells. This was the only potable water source available on a year-round basis 11 at that time.

12 Even with the advent of the Rio Grande Project, reliance on ground water -13 continued. The U.S. Department of the Interior, Bureau of Reclamation 14 (USBR), designed the project facilities for agricultural irrigation and electric 15 power generation. While there were provisions in the enabling legislation to -16 address the municipal needs, there were no incentives or facilities to use the 17 surface waters of the Rio Grande because of the seasonal availability and 18 relatively low water quality without treatment.

19 Caballo Dam and Reservoir were constructed on the Rio Grande downstream 20 of Elephant Butte in 1936 to 1938. The Caballo facility served as a buffer to _21 regulate the different release requirements between power generation and 22 irrigation demands. In addition, it was sized to provide flood storage (100,000 23 at) to justify substantial cost reductions in the Rio Grande Rectification _24 Project (1933) which channelized the Rio Grande along the international 25 boundary from the American Dam to Fort Quitman.

-26 EI Paso's Water Supply

27 As early as 1940, EI Paso, Texas, determined the ground water aquifers were _28 being overdrafted due to well pumping by water users. In response to that 29 concern, the city constructed the Canal Street Water Treatment Plants, the 30 first of which came on line in 1943 to partially meet the water demands of the _31 community. In 1963 a second Water Treatment Plant was added at the same 32 location to increase surface water treatment capacity. The water supply for 33 these plants was derived from the Rio Grande Project annual allocation of _34 surface water to the EPCWID# 1. The district enacted restrictions in its 35 operational regulations to limit the amount of water that could be converted to 36 municipal use. In subsequent years, EPWU further expanded its surface water 37 treatment capacity; however, the plants could only be operated during the 38 irrigation season because of water availability.

9 1 Litigation

2 In 1980, the EPWU filed applications with the Office of the State Engineer of 3 New Mexico to drill water wells in Dona Ana County, New Mexico. This 4 action resulted in extended litigation between EI Paso, the EPWU and several 5 public entities in New Mexico. While the litigation process fostered regulatory 6 changes, statutory changes, and a Supreme Court ruling, it did not allow 7 EPWU to obtain well pennits. The discovery process and hearings during the 8 litigation elicited the awareness and concern of the parties involved for 9 protection of regional water resources and the lack of quantitative analyses.

10 Litigation Settlement

11 As a result of these concerns, EI Paso along with EPCWID#I, EBID and the 12 New Mexico public entities separately conducted major planning studies to 13 evaluate their present and future circumstances. The two studies, The Water 14 Resource Management Plan, prepared by Boyle Engineering Corporation for - 15 EPWV and EPCWID#I, and Surface Water Supply Alternatives for the City 16 ofEl Paso and Southern New Mexico Water Users. prepared by Engineering­ 17 Science, Inc., for the New Mexico public entities, provided valuable - 18 information to negotiate a litigation settlement agreement. A settlement of 19 litigation was achieved, resulting in an agreement dated March 6, 1991. 20

21 Key conditions in the settlement are summarized below:

_22 I. Formation of a Joint Commission.

23 2. Conservation of water is first priority. -24 3. Use of the surface water of the region for all purposes. 25 4. Perform water resource studies applicable to the entire project area.

26 The Commission -27 In compliance with the litigation settlement agreement, the Joint Commission 28 (now the New Mexico-Texas Water Commission) was formed, and now 29 includes participation by entities who were not parties to the litigation but -30 have a vital interest in the long-term water resources of the region.

31 This Commission has also proceeded with the stipulated planning effort by -32 hiring Boyle Engineering Corporation and Engineering-Science, Inc., to 33 combine the information and data previously gathered through the individual

10 1 studies and to perform further studies to formulate a plan that will best serve 2 the water resource interests of all the parties. This report presents the findings 3 of certain elements of that study, which is proceeding by distinct phases. 4 Phase I, which was completed and previously reported, dealt with 5 identification of alternative methods to more fully use surface water supplies 6 for M&I purposes and to quantify increased resource utilization through water 7 loss mitigation.

8 The Commission has sought to include all parties of interest in the region, 9 including local and county officials, officials from the states of Texas and 10 New Mexico, the International Boundary and Water Commission, The Bureau II of Reclamation, the Rio Grande Compact Commission, and officials of 12 Ciudad Juarez.

-13 The driving force of the planning effort is to tap renewable water sources to 14 serve people in both the urban and rural areas of the region, with the provision 15 that both the riparian and instream ecosystems be preserved, enhanced, and -16 restored. Since the high Chihuahua Desert macrocosm of the region is fragile 17 in nature, future water resources must be based on sustainable and renewable 18 surface water sources in areas where ground water is being rapidly depleted. -19 The areas of depleted ground water resources must also be restored, held in 20 reserve and perpetually maintained. There is also an awareness that the 21 region's attractive climatic will foster future immigration and popUlation -22 growth.

23 Given these parameters, the Commission is committed to preserving and _24 restoring the Hueco and Mesilla Basins (or Bolsons) and the Rio Grande 25 River, all of which are essential elements in this environmental stability and 26 quality of the region. The word "Bolson" is Spanish for "water pocket" and _27 has evolved into a technical term describing a type of valley fill aquifer. These 28 aquifers will be referred to as basins, for clarity to the general reader, in the 29 remainder of the report.

-30 The Commission has specifically directed that the water resource limitations 31 be identified and that a conservation program be included as an element of 32 this study.

33 This report presents a Phase IIIIII study that evaluates the feasibility of each 34 of three alternative objectives for conveyance of surface water. These -35 alternatives all offer possibilities for facilitation of Commission goals.

11 1 Subject of the Study for Phases II and III

2 The focus of the overall study is to evaluate the potential efficacy ofa 3 protected surface water conveyance to various entities. This conveyance might 4 decrease system losses, make better use of the project water, preserve water 5 quality, restore over-stressed ground water aquifers, and provide sustainable 6 water resources to meet the needs of the region, in accord with achievable 7 environmental improvements. This focus is intended to meet the goals 8 identified in the Study Criteria Memorandum in Appendix A.

9 By general consent of the Commission, the consultant has been directed to -10 study the feasibility and effects of constructing surface water conveyance 11 facilities from the appropriate upstream location to meet three distinctly 12 different purposes or alternative objectives.

13 Alternative Objective 1

14 Alternative Objective 1 will convey the Rio Grande Project surface water 15 allocation of the Texas and Mexican entities and a small portion of the 16 Elephant Butte Irrigation District (EBID) allotment for M&I uses in Southern 17 Dona Ana County, from the Percha Diversion Dam, through the EBID in a 18 lined canal, without commingling with other irrigation or storm water, to the 19 American Dam in EI Paso.

20 Alternative Objective 2

21 Alternative Objective 2 will convey all of the surface water allocation of the 22 Rio Grande Project from the Percha Diversion Dam in lined and upgraded _23 canals to the American Dam in EI Paso. All historic irrigation supplies would 24 be served by diversion from the canal with an option to re-divert instream 25 flows in the Rio Grande for blending with the water that has been diverted _26 from the canal. Additionally, provisions would accommodate two new 27 diversions to supply surface water to two new regional water treatment plants 28 for distribution to M&I users.

29 Alternative Objective 3

-30 Alternative Objective 3 will divert the surface water allocation attributable to 31 the EPWU and the Republic of Mexico from the outlet works of Caballo Dam 32 through a closed conduit to a termination at the Jonathan Rogers Water _33 Treatment Plant located near the Riverside Diversion Dam in El Paso. 34 Provisions will be made to divert flows at a point between the communities of

12 1 Anthony and Canutillo, Texas, to serve a future water treatment plant. 2 Provisions will also be made to divert flows at the Robertson-Umbenhauer 3 Water Treatment Plant.

4 Additional Options

5 In addition to the three basic conveyance alternatives and associated regional 6 water treatment facilities, other possible enhancements to the project have 7 been considered. These include additional facilities, modes of operation and 8 possible environmental improvements which could be implemented with 9 construction of a project. These options may help to accomplish the primary 10 goal of preserving of the Hueco and Mesilla Basins, increase the efficiency of 11 surface water use, and promote positive environmental benefits. They are 12 discussed under the section Additional Considerations near the end of this 13 report.

_ 14 General Methods Applied

15 Data used for this study were those which were generally available from 16 records existing in the user agencies, and state and federal agencies. No field 17 investigations, surveys, or other data generation have been performed. The 18 data that are applicable to the purposes of this study have been collected, 19 compiled, and evaluated.

20 Subsequent phases of the project development will require substantial field 21 investigations.

22 The approach of this study was to analyze the holistic effects on the entire 23 water system (surface and ground water) of implementing any of the three --24 objectives. A water budget analysis method was applied. The baseline water 25 budget is representative of the status quo against which each of the 26 alternatives can be compared.

27 Concurrently with the water budget analyses, conceptual engineering of each 28 of the three alternatives was developed to a degree which allows evaluation of _29 the physical feasibility and the project construction cost.

30 The planning horizons used in these studies are: -31 o Facilities come into service-200S 32 o Facilities in service to expanded population-2015

33 o Study Horizon-2035

13 I Approach

2 The approach taken in this study was to consider the conjunctive or 3 complementary use of both surface and ground water for the region-wide 4 needs, and also to identify means by which the overdrafted ground water 5 resource can be stabilized.

6 If the Commission detennines that sufficient benefits are identified by these 7 analyses, it will select one of the alternative objectives to be refined by an 8 environmental assessment and preliminary engineering toward the end of 9 funding improvements that will be required to best use the water resources of 10 the region.

14 Data Collection

1 The data collection for the study consisted of compiling readily available 2 infonnation to develop a base map, to prepare a water budget, and to locate 3 and size two regional water treatment plants and their associated conveyance 4 and distribution systems. The study relied upon existing infonnation, and no 5 new data were developed. Existing data were obtained from a large variety of 6 sources and compiled and evaluated for use in the study. Due to the large 7 study area, and the many entities within the study area, there were many cases 8 where infonnation was available in varying detail and quality. The purpose of 9 this section is to report the infonnation sources used to complete the study.

-10 Base Map

11 Maps were developed as a part of the planning effort. The data used for the -12 Rio Grande Project base maps included data from the U.S. Census Bureau, 13 the EBID, and the U.S. Geological Survey (USGS).

_14 The base data (roads, railroads, river, hydrology, and political boundaries) 15 were acquired from the U.S. Census Bureau in the form of Tiger files. The 16 Tiger files included all of Sierra County, Dona Ana County and El Paso 17 County. It was decided that the quality of these data was adequate for 18 planning purposes.

19 The irrigation district boundary within the Mesilla Valley was provided by the -20 EBID. This infonnation was required to determine acreage within the valley 21 served by surface water.

-22 In critical locations within the project area (valley constrictions, possible raw 23 water conveyance routes and possible treatment facility and distribution line 24 locations), topographic infonnation was required. All available 1:24,000 -25 topographic, public land survey, and boundary information was obtained from 26 the USGS. The topography was constructed from three dimensional digital 27 elevation models (DEMs) where available. The public land survey and -28 boundary infonnation was used to provide additional reference points and a 29 common coordinate system.

-30 Water Budget

31 A water budget was developed for nine selected years (three dry, three -32 average, and three normal) to provide an assessment of the effects of 33 alternatives on the hydrologic system. The years studied were 1951, 1967, 34 and 1971; 1970, 1980, and 1984; and 1988, 1989, and 1993 for dry, average -35 and normal years respectively. Data were collected for the Rincon Valley, the 36 Mesilla Valley, and the El Paso Valley. The following is a listing of the 37 sources for all readily available data used in the water budget:

15 1 Precipitation

2 Data for the Rincon and Mesilla Valleys were compiled from three stations 3 (Caballo Dam, New Mexico State University and El Paso). The data were 4 obtained from USBR Rio Grande Project historical records and USBR Annual 5 Operating Plan reports.

6 Agricultural River Diversion

7 Data were available at each of the three diversion dams (percha Dam­ 8 including Percha and Bonita Laterals, Leasburg Dam, and Mesilla Dam) in 9 the USBR Rio Grande Project historical records and the USBR Annual 10 Operating Plan reports.

II Drain Flow

- 12 Data were available on a monthly basis from USBR drain flow gaging 13 records.

14 M&I Ground Water Pumping 15 Data for the Mesilla Valley were taken from Frenzel and Kaehler (Reference -16 7) and from Hamilton and Maddock (Reference 9).

Lateral and Canal Seepage

18 Data for 1951 through 1971 were based on monthly USBR estimates of canal 19 seepage and famt deliveries available in USBR project files. These estimates 20 are also reported on an annual basis in New Mexico State Engineer Technical 21 Report 43 (Reference 23).

22 Vertical Hydraulic Conductivity

Data for estimating deep percolation were available for the Mesilla Valley from the Wright Water Engineers groundwater study (Reference 12).

16 1 Irrigation Return Flow & Canal Waste Return Flow

2 Data for 1951 through 1971 were based on monthly USBRestimates of canal 3 waste and return flow available in USBR project files. These estimates are 4 also reported on an annual basis in New Mexico State Engineer Technical 5 Report 43 (Reference 23).

6 River Flow

7 Data were available from the USGS, the USBR, and the International 8 Boundary and Water Commission (lBWC) which maintain gaging stations at 9 points along the river for both the Rincon Valley, the Mesilla Valley and EI 10 Paso Valley.

11 River Seepage _12 Data were available from New Mexico State Engineer Technical Report 43 13 (Reference 23), Wright Water Engineers (Reference 12), Hamilton and 14 Maddock (Reference 9) and Frenzel and Kaehler (Reference 7).

15 Ground Water Boundary Flux -16 Estimates of the ground water boundary flux for the Mesilla Valley were 17 available from the Frenzel and Kaehler (Reference 7) and Hamilton and 18 Maddock (Reference 9).

19 River IDS -20 Data were obtained from the mwc for both the Rincon Valley and the 21 Mesilla Valley.

22 M&I Return Flow IDS 23 Data were taken from the New Mexico Water Resources Research Institute 24 Report No. 064 (Reference 15).

-25 Drain Inflow IDS Data were available from the USBR and the mwc for both the Rincon Valley and the Mesilla Valley.

17 I Agricultural Ground Water Pumping

2 Estimates for the Mesilla Valley were available from groundwater modeling 3 studies of the Mesilla Valley by Wright Water Engineers (Reference 12), 4 Frenzel and Kaehler (Reference 7) and Hamilton and Maddock (Reference 9). 5 Groundwater pumping estimates for the years of 1975 and 1980 for the 6 Rincon Valley were available from New Mexico State Engineer Technical 7 Reports 43 and 44 (References 23 and 19) respectively.

8 Water Demand

9 The data compiled to size the two proposed regional water treatment plants 10 included population projections, per capita daily uses, and projected peaking 11 factors. The population data for New Mexico were obtained from the Dona 12 Ana County Planning Department and the City of Las Cruces. These data 13 included the 1990 Census figures for Dona Ana County. Population figures 14 for the Texas area served by the regional water treatment plants were - 15 calculated based on estimated water requirements from Boyle Engineering 16 Corporation for that area for the year 2015.

17 Conveyance, Treatment and Distribution

18 Data compiled for the three alternative conveyance and distribution systems - 19 included existing canal capacities, alignments, and lengths and topographic 20 mapping. Maps and reports describing existing water systems in the study 21 area were obtained to determine pressure zones, and locations and capacities -22 of treated water storage reservoirs and main transmission lines. Existing water 23 treatment plant design information was also obtained from the City ofEl 24 Paso's Jonathan Rogers Water Treatment Plant report.

18 Alternative Objectives

1 The alternative conveyance systems named and briefly discussed in the 2 introduction to this report are not conceived to meet a single common 3 objective. Different portions of the total Rio Grande Project supply are 4 conveyed to different end users in each of the three alternatives considered. In 5 addition, Alternative 2a considers a dual system which allows controlled 6 blending of the protected contents of the Alternative 2 canal with return flow 7 and runoff in a separate canal system. For this reason, the alternatives 8 investigated are "alternative objectives" rather than alternative means of 9 meeting a common objective. This study is, therefore, not a conventional 10 engineering feasibility study. It is a reconnaissance level study to assist the 11 Commission in selecting a suitable common objective.

12 Alternative Objective 1

13 The objective of this alternative is to supply water on a year-round basis to the 14 Texas entities of the EPCWID#I and EPWU, to the Republic of Mexico, and 15 possibly for relatively small M&I uses in Southern Dona Ana County, 16 independent of other New Mexico entities. The necessity to provide some New 17 Mexico water in this alternative is required only if the Anthony Regional 18 Water Treatment Plant, discussed later, supplies southern Dona Ana County.

19 The TexaslMexico allotment of the annual Rio Grande Project surface water 20 allocation, and a small portion of the EBID allotment as required by Southern -21 Dona Ana County for M&I uses, would be diverted at the Percha Diversion 22 Dam on the Rio Grande, conveyed in a lined canal and delivered in part to a 23 proposed water treatment plant in the Anthony area, and the rest to the -24 American Canal headworks at the American Dam on the Rio Grande in EI 25 Paso. The portion of the flow allocated to Mexico may be released to the Rio 26 Grande at the American Dam, or alternatively, be diverted for treatment at the -27 Anthony water treatment facility and delivery to a point on the international 28 boundary near Anapra, NM. This would provide for Mexico's allocation of 29 project water to be converted to M&I purposes for Ciudad Juarez, as -30 determined by authorities in Mexico.

31 The water would be conveyed in a lined canal that would provide for a _32 diversion at the Anthony water treatment plant and prevent all other 33 inflow/outflow between the termini. The terminus at the American Dam would 34 allow for the American Canal, and its extension to Riverside Canal, to be __ 35 used as the conveyance system below American Dam.

36 Alternative Objective 2 37 The objective of this alternative is to provide Rio Grande Project system-wide 38 improvements to meet the needs of all regional water agencies. This alternative

19 1 is conceived to upgrade the Rio Grande Project facilities to serve a modem 2 mission of preserving and protecting the ground water resources of the region 3 by the improved uses and year-round delivery of the renewable and 4 sustainable surface water resource.

5 The concept of this alternative is to construct a lined canal along existing main 6 canals from the Percha Diversion Dam on the Rio Grande to a terminus at the 7 American Dam on the Rio Grande in EI Paso. The full annual allocation of the 8 Rio Grande Project would be diverted to this conveyance less a constant 9 instream release determined to be sufficient for riparian purposes. The 10 conveyance canal would utilize existing alignments and rights-of-way to the 11 greatest extent practical. A new segment of canal will be required to connect 12 the Rincon Valley and the Mesilla Valley through Selden Canyon on the Rio 13 Grande.

14 The objective is to maintain all existing agricultural water interests of the 15 region through more efficient distribution systems. From the water savings -16 derived from modem facilities, surface water can become available for 17 application to M&I needs. The municipalities presently are overdrafting the 18 ground water aquifers in the United States and the Republic of Mexico. The -19 City ofEI Paso and Ciudad Juarez will exhaust the Hueco Basin (aquifer) by 20 around the year 2023 if present trends continue (see Figure 1). Both cities are 21 heavily dependent upon the Hueco source for their supplies. The city of Las -22 Cruces has created a major cone of depression in the Mesilla Basin. Inasmuch 23 as there is hydraulic connectivity between the area aquifers and the Rio 24 Grande, the water table of the underlying aquifers will impact the surface -25 water flow rate as shown in the water budget analyses.

26 Alternative Objective 2a

27 The objective of Alternative 2a is identical with Alternative 2, with the 28 addition of optional facilities to reuse and blend instream flows in the Rio -29 Grande with the diversions to agricultural irrigation. As described above for 30 Alternative 2, the conveyed surface water in the main canal is protected from 31 inflow of storm runoff, drain discharges, spills (wasteway releases), and -32 return flows. Alternative 2a provides for facilities to divert these instream 33 flows at Leasburg Diversion Dam and Mesilla Diversion Dam into lateral 34 feeders for purposes of reuse for agricultural irrigation. At those points of -35 diversion, surface water from the main canal can be blended with the reuse 36 diversion in a blended water canal to attain quality and quantity of flow 37 desirable by the user. 38 These facilities will involve parallel conveyance laterals which cannot 39 backflow into the spine conveyance channel. Substantial additional cost is

20 o o~ N

0 N, ('I') c E 0)' 0 0 0 "- , N .- "- CO +-' ' '+- ::)' (I) 0)-' - C>~' a. CO 0 (I) a.::> N 0 0 ES N ~ ::)0.. '- c.. w CO .-~ ~ :J 0 T- C'" 0 « N .-C en co 0 (ll 0 0 0 N 0 (I) :J 0 I 0) 0) 0 0 0 0 0 0 o T- o 0 0 0 0 0 0 0 0 0 0 0 co I.{) ~ ('I') N T-

:JV 000 ~ - a6l3JOlS Jall3M punOJ8 1 involved as shown on the cost analyses below. In addition, as illustrated by the 2 results of the water budget discussed later in the report, available supplies for 3 blending may at times be poorer in quality than the protected canal flow. 4 However, the costs and quality impacts should be evaluated against the benefit 5 of the additional total surface water which will be available for agricultural 6 uses.

7 Alternative Objective 3

8 The objective of this alternative is to convey surface water from the outlet 9 works of Caballo Dam, through a closed conduit (Pipe), to the City ofEl 10 Paso. The facility would provide capacity to convey the full annual allocation 11 of Mexican Rio Grande Project water on a uniform year-round basis, and the -12 portion of the EPCWID# 1 allocation attributable to EPWU on a basis of daily 13 demand by EPWU.

14 This alternative will convey raw water from Caballo Reservoir directly to 15 water treatment facilities owned and operated by EPWU for treatment and 16 distribution to El Paso County customers, and for treatment and delivery to 17 Ciudad Juarez on a wholesale basis.

18 Physical Attributes of Conceptual Alternatives

19 Alternative 1.

-20 Conveyance: 21 Open-channel with trapezoidal cross-section, concrete lined. 22 (See Figure 2)

23 Length and termini: 24 Point of beginning: Percha Diversion Dam. ._25 Point of termination: American Diversion Dam . 26 Length ofmain channel: 103.7 statute miles.

27 Route: (See Figure 3) in pocket -28 Parallel to, and adjacent to the Rio Grande.

29 Ancillary structures: (See Figures 4, 5, 6) -30 Three river crossings (inverted siphons). 31 Flumes and siphons at stream and arroyo crossings. 32 Wasteway structures. -33 Check dams and drop structures as determined by hydraulics.

22 1 Diversions (turnouts See Figures 7,8): 2 Only one intermediate diversion point to supply Anthony WTP.

3 Schematic Flow Diagrams for Alternative 1 for years 2005, 2015, and 4 2035 are presented in Figures 9, 10, and 11 respectively.

5 Alternative No.2.

6 Conveyance: 7 An open-channel with trapezoidal cross-section, concrete lined. 8 (See Figure 12)

9 Length and termini: 10 Point of beginning: Percha Diversion Dam. -11 Point of termination: American Diversion Dam. 12 Length of main channel: 102.4 statute miles. _13 Route: (See Figure 3) in pocket

23 Canal Cross Section for Alternative 1

B

Reach Length, miles B, feet 0, feet H, feet

Percha Dam to 88.0 12.0 9.0 11.0 AnthonyWTP

Anthony WTP to Closed Conduit 13.7 12.0 9.0 11.0

Closed Conduit to American Dam 2.0 2-10 ft x 10ft Barrels

Figure 2 « I, c O'l C I .r:.0 .- ..::> -.:t ... 0 .0.. ~ 0 (]) 1 (f) I..... I..... ~ _0 :l b 0 0> I ~ u (])u...I...... - l' 0..> ,...., ,.... ~.- b 1-0::: I ~ '"

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~1 u m 96'-0' 30'-0" 36'-0" 30'-0"

6'-0· 24' -0" 24'-(1' 6'-(1

SECTION 8-8

II I I I I I I I I 'I , I

~O\ ERFLOW CHANNEL ,

\

RADIAL GATE

SECTION C-C

Typical Check Structure Sections Figure 6 STOP LOG GUIDE

E

D L

~j LE

~CANAL LINING GRATE SLOPE - 1 1/2:1

PLAN

Typical Turnout Figure 7 GATE DETAILS NOT SHOWN CANAL GRATE

VERTICAL GATE

STOP LOG GUIDES

SECTION D-D /GRATE

"u:r;r=1IIIIm==a:;ou"r-

I /1..-- STOP LOG fir'" GUIDE

/TRASHRACK

III 1IIIIIIIIIIIITlHTfT nr

SECTION E-E SECTION F-F

Typical Turnout Sections Figure 8 +- Alternative 1 Texas/Mexico Canal Year 2005

155 ! EPWU 1176 1146 ~ 303 Mexico I 88.0 \ 15.7 ~ Irrigation ~ .~ ~~ r§- ~0 30 ':(--~ 688 Anthonywrp EPC\NIO#1

VVTP, cfs flow, cfs mileage Q~ outflow,cfs Legend Figure 9 Alternative 1 Texas/Mexico Canal Year 2015

570 EPCV\AD#1

918 756 88.0 15.7 ~ ~~ ~0 162 186 AnthonyWTP EP\MJ

WTP, efs

f10wj efs ( .~ mileage Q'l>1 Legend Figure 10 Alternative 1 Texas/Mexico Canal Year 2035

338 EPC\MD#1

757 524 88.0 15.7 (b> ~o:: ~ClJ 243 186 AnthonyWTP EP\MJ

\I\/TP f'f" v v I I ! ""Iv flow, cfs ~ mileage Q'#' outflow, cfS Legend Figure 11 Canal Cross Section for Alte rn ative 2

Reach Length, miles B, feet D, feet H, feet

Arrey Canal 4.75 20.0 12.5 14.5 Garfield Canal 9.33 20.0 12.5 14.5 Hatch Canal 8.33 20.0 12.5 14.5 Selden Canyon 20.08 18.0 12.5 14.5 Leasburg Canal 13.03 16.0 12.5 14.5 Mesilla Lateral 9.09 14.0 12.0 14.0 West Side Canal 13.79 12.0 11.0 13.0 I La Union Main 4.28 12.0 10.5 12.5 I La Union East 10.6 10.0 10.0 12.0 New 7.33 10.0 9.5 11.5 I Closed Conduit 1.80 2-10 ft x 10 ft Barrels

I

I ! Figure 12 I 1 The main channel will consist of reconstruction of the existing canal (Arrey, 2 Garfield, Hatch, Angostura, Leasburg, and West Side). Through the Selden 3 Canyon of the Rio Grande there will be a new alignment required for a 4 distance of approximately 23 miles.

5 Ancillary structures: (See Figures 4, 5, 6) 6 River crossings, new and rehabilitated. 7 Flumes and siphons for arroyo crossings 8 Check dams 9 Drop structures. -10 Metering facilities.

11 Diversions (turnouts Figure 7, 8): 12 All existing points of diversion and turnouts will be maintained and 13 serviced from the improved canal. There will be two additional points 14 of diversion in the reaches between the termini to provide raw surface 15 water to each of two new water treatment plants (Las Cruces and 16 Anthony).

17 Schematic Flow Diagrams for Alternative 2 for years 2005, 2015, and - 18 2035 are presented in Figures 13,14, and 15 respectively.

_19 Alternative 2a

20 The physical features of Alternative 2a are identical with Alternative 2 with 21 the addition of the blending facilities at Leasburg and Mesilla Diversion 22 Dams, and the extension of the blended water parallel laterals. A schematic of 23 the features is shown in Figure 16. Schematic Flow Diagrams for Alternative 24 2a for years 2005, 2015, and 2035 are presented in Figures 17, 18, and 19 25 respectively.

-26 Alternative 3

27 Conveyance: 28 A closed conduit will be conceived to be a 120 inch diameter circular 29 pipe connected to the outlet works of Caballo Dam. The inlet 30 pressure will be that provided by the Caballo Reservoir surface 31 elevation. No booster pumping will be required. The pipe will be 32 designed to withstand static hydraulic pressure when shut-offat the 33 lowest terminus. Pressure-reducing stations and maintenance valves 34 will be used.

34 Alternative 2 New MexicolTexas/Mexico Canal '::. r:. n Year 2005 ,,-' '_j,-,I 30 Las r . r c";' 1_' .::.; L Cruces 1_ ") t." WTP

3406 3356 3056 Garfield Hatch Leasburg 9.33 8.33 13.03

\ \ -~ i [) vr,o toG -100 200 4- ./ ;~) ~ C If-' i=BID~ EB1D E,Esi[) L- t_.i i L) E:E~I[J

30 Anthony I WTP, cfs WTP flow cfs 7' t 155 can~i Name{ 1656 ~ mileage \ 1976 La Unio 1396 1146 '" /' EPWU West Side Main La Union East New 303 Mexico Q'lJ. Ol_l~f;(j\i\/,~fs 13.79 4.28 10.60 \ 7.33, Irrigation Legend .~fb. \ _(}).<::'- " E8 8 't- 1l A(j E-I-):~' "!l['\ ~'O~ 320 230 2._ ...) \.... ,,"). .. '"J V V I LI .... ~ ,'." 6, 'I r-\ E_! ''-j "Vi",' EPCVViD EFCVVID 't-~v #1 .f1 • -41 t;' #1 ie, Figure 13 *Closed Conduit Alternative 2 New MexicolTexas/Mexico Canal Year 2015 350 39 Las East CrucEs Side WTP 3157 3107 2807 2293 Garfield Hatch Leasburl Mesilla 13.03 9.33 8.33 9.09 .~ ~ ..

50 50 100 200 475 ~0225 EBID EBID EBID EBID EBID EBID 162 Anthony WTP, cfs WTP flow, cfs 7' t Canal Name/ 1398 186 1718 EPWU ~ mileage t West Side Q'lJl outflow,cfs 13.79 1.80 Legend .~tb­ /~ ~0~ 250 "~ 570 320 230 EPCWID EPCWID EPCWID EPCWID ~t§ #1 #1 #1 #1 ~

*Closed Conduit Figure 14 Alternative 2 New MexicolTexas/Mexico Canal Year 2035 30 Las 350 Cruces East WTP Side t 3057 3007 2707 2142 Garfield Hatch Leasburl Mesilla 8.33 13.03 9.09 9.33 .~ ~'.

50 50 100 200 475 ~0 225 EBID EBID EBID EBID EBID EBID 243 WTP, cfs flow, cfs ,. 186 Canal Name/ EPWU ~ mileage ( 1567 774 524 WestSide nion East New ~~ outflow,cfs 13.79 10.60 Legend .~fb. ~0~ 320 230 250 EPCWID EPCWID EPCWID #1 #1 #1

*Closed Conduit Figure 15 Dual Canal Section Alternative 2a Blended Water Canal Fresh Water Canal

1.5 H

~h ~~~,">H~T":,"':J,+~ I( ~ I( ~ Bb Bf Blended Water Canal Fresh Water Canal Reach Length,- mi B, feet 0, feet H, feet Reach Length, mi B, feet 0, feet H, feet Percha Dam to Las Cruces 13.7 8.0 7.5 9.5 to Selden Canyon 22.4 16.0 12.5 14.5 to Mesilla Dam 11.9 6.0 5.0 6.5 to Leasburg Dam 20.1 15.0 12.5 14.5 West Side Canal - 1 14.4 8.0 8.0 10.0 to Las Cruces WTP 13.7 14.0 11.0 13.0 West Side Canal - 2 3.6 7.0 6.5 8.0 to Mesilla Dam 11.9 14.0 11.0 13.0 West Side Canal - 3 11.0 6.0 5.0 6.5 to Anthony WTP 18.0 10.0 9.0 11.0 West Side Canal - 4 5.0 4.0 3.5 5.0 to American Dam 18.0 10.0 9.0 11.0

Figure 16 Alternative 2a - Blending Option Year 2005 100 R 700 ) 225 \ \ 600 475 EBID 225 EBID 600 30 Las Cruces 3131 3081 2981 2181 t 2151 Garfield Hatch Angostura & Selden Canyon 11 Leasburg Mesilla 9.33\ 8.33 '\ 20.08 ~ 1\ 13.03 9.09 .-&fb. 50 EBID 50 EBID 100 EBID -.fliJ 200 EBID ~0~

175 R 350 East Side Canal return, cfs ~ 800 480 250 )blended flow fresh, cfs fI WfP, cfs 320\ \ 230 ~ 250 ow 975 EPCWlD*1 EPCWlD#1 EPCWlD#1 Canal 975 155 1176 1146 ?' EPWU WestSide New / 303 Legend 7.33 .-&'b­ 13.79 ~0~ Figure 17 Alternative 2a - Blending Option Year 2015 '1 00 I;~ 700 225 / \ \ 600 475 EBID 225 EBID 600 39 Las Cruces 2882 2832 2732 "I 1932 t 1893 Garfield Hatch Angostura & Selden Canyon Leasburg Mesilla 9.33 8.33 20.08 13.03 9.09 .~fb. 50 EBID 50 EBID 100 EBID 200 EBID ~0~

175 R 350 East Side Canal return, cfs "')L- 800 480 250 )blended flow fresh, cfs fI WTP. cfs ~ 320\ \ 230 " 250 ow ' 975 EPCWlD1II1 EPCWlD#1 EPCWlD#1 Canal 975 162 Anthony 186 918 918 j 756 7'56 /EPWU WestSide La Union, La Union East New Legend 13.79 10.60 7.33 .~fb. ~0~ Figure 18 Alternative 2a - Blending Option Year 2035 1"n R u. ) 700 225 \ \ 600 475 EBID 225 EBID 600 90 Las Cruces 27'82 2732 2632 '" I 1832 t 1742 Ganfield Hatch Angostura & Selden Canyon Leasburg Mesilla 9.33 8.33 20.08 13.03 9.09 .'&~ 50 EBID 50 EBID 100 EBID 200 EBID ~0~

175 R 350 East Side Canal ~ 800 480 250 320\ \ 230 '\ 250 975 EPCWlD#1 EPCWlD#1 EPCWlD#1 975 243 Anthony 186 767 167 i 524 524 /EPWU West Side La unionl La Union . East New 13.79 10.60 7.33 ·'&~ ~0~ Figure 19 1 Length and Termini: 2 Point of beginning: Caballo Dam Outlet Works. 3 Point oftennination: Jonathan Rogers Water Treatment Plant.

4 Length of Conduit: 113.0 Statute miles.

5 Route: (See Figure 3) in pocket

6 The alignment of the pipeline will follow public rights-of-way where 7 possible, paralleling US 85 highway where hydraulically feasible.

8 Ancillary Structures: 9 Air and vacuum relief stations as dictated by profile requirements. 10 Metering Station. -11 Maintenance valve stations.

12 Diversions (turnouts): 13 Wasteways to the river. 14 Feed line to Anthony WTP. 15 Feed line to Robertson-Umbenhauer WTP. 16 Feed line to Jonathan W. Rogers WTP.

17 Schematic Flow Diagrams for Alternative 3 for years 2005, 2015, and 18 2035 are presented in Figures 20, 21, and 22 respectively.

19 Capital Cost Estimates

-20 Estimates of capital costs for Alternatives 1, 2, 2a, and 3 are presented in 21 Tables 1,2,3, and 4 respectively. Estimates have been based on the Cost 22 Basis Memorandum (see Appendix B) for items included in the Memorandum, -23 with some modifications where these appeared reasonable. Detailed quantity 24 and characteristic breakdowns for canal construction for Alternatives 1,2, and 25 2a, and for pipe construction for Alternative 3 are presented in Appendix C.

42 ,------Alternative 3 Texas/Mexico Pipeline Year 2005

62 93 EPWU EPWU

261 155 86.7 9.1 15.0 . ufli~ 106 ~ Canutillo ~~ WTP

WTP, efs ," flow, efs (

Legend Figure 20 Alternative 3 Texas/Mexico Pipeline Year 2015

62 124 EPWU EPWU

339 186 86.7 9.1 15.0 ~ . (;fli 153 ~ Canutillo t:(:~ WTP

I WTP, efs ) flow, efs r/ mileage ()~~

Legend Figure 21 Alternative 3 Texas/Mexico Pipeline Year 2035

62 124 EPWU EPWU

390 390 186 Li24 2.1 86.7 9.1 15.0 ~o 'v-..fb. ~ \. \, . uft} (lj &0· e;f§J «0 204 ~ Canutillo ~ WTP

~ WTP,,,,cfsI ) flow, cfs ( mileage <;)~~

Legend Figure 22 Table 1 Capital Costs for Alternative No.1

Item Unit Price Quantity Cost $ Unit

Canal, concrete lined with 280 foot 537,900 ft $150,612,000 maintenance road and fence

Concrete Pipe 3.25 in dia-ft 2,622,000 in dia-ft $8,521,500

Special Excavation 10.50 Cy 62,963 Cy $661,112

Major Headgates (Anthony) 150,000 each 1 each $150,000

Check Structures 300,000 each 1 each $300,000

River Crossing 750,000 each 3 each $2,250,000

Bridge Crossings 100,000 each 91 each $9,100,000

Rights-of-way Non Orchard 10,000 acre 1,275.9 acres $12,759,493

Orchard 20,000 acre 82.6 acres $1,651,515

Sub-total $186,005,619

Adjusted Subtotal to Year 2000 119% $221,346,687

Construction Contingency 20% $44,269,337

Subtotal Construction Cost $265,616,024

Contractors Profit and Overhead 11% $29,217,763

Engineering and Administrative 14% $37,186,243

TOTAL $332,020,030

6/21/94 Table 2 Capital Costs - Alternative 2

Item Unit Price Quantity Cost $ Unit

Canal, concrete lined with 320 foot 224,400 ft $71,808,000 maintenance road and fence

Canal, concrete lined with 310 foot 68,800 ft $21,328,000 maintenance road and fence

Canal, concrete lined with 300 foot 48,000 ft $14,400,000 maintenance road and fence

Canal, concrete lined with 290 foot 95,400 ft $27,666,000 maintenance road and fence

Canal, concrete lined with 280 foot 94,700 ft $26,516,000 maintenance road and fence

Special Excavation 10.50 CY 62,963 CY $661,111

Concrete Pipe 3.25 in dia-ft 2,622,000 in dia-ft $8,521,500

Major Headgates 150,000 each 12 each $1,800,000

Minor Headgates 15,000 each 90 each $1,350,000

Check Structures 375,000 each 36 each $13,500,000

River Crossing 750,000 each 5 each $3,750,000

Bridge Crossings 100,000 each 117 each $11,700,000

Connection to Wasteways 75,000 each 10 each $750,000

Rights-of-way Non Orchard 10,000 acre 435.0 acres $4,349,773

Orchard 20,000 acre 142.4 acres $2,847,670

Sub-total $210,948,054

Adjusted Subtotal to Year 2000 119% $251,028,185

Construction Contingency 20% $50,205,637

Subtotal Construction Cost $301,233,821

Contractors Profit and Overhead 11% $33,135,720

Engineering and Administrative 14% $42,172,735

6/21194 TOTAL $376,542,277 Table 3 Capital Costs for Alternative 2a

Item Unit Price Quantity Cost $ Unit

Canal, concrete lined with 310 foot 224,400 ft 15' to 16' width $69,564,000 maintenance road and fence

Canal, concrete lined with 300 foot 126,500 ft 14' width $37,950,000 maintenance road and fence

Canal, concrete lined with 280 foot 362,100 ft 8' to 10' width $101,388,000 maintenance road and fence

Canal, concrete lined with 270 foot 142,700 ft width < 8' $38,529,000 maintenance road and fence

Special Excavation 10.50 CY 62,963 CY $661,1ll

Concrete Pipe 3.25 in dia-ft 2,622,000 in dia-ft $8,521,500

Major Headgates 150,000 each 12.00 each $1,800,000

Minor Headgates 15,000 each 90.00 each $1,350,000

Check Structures 375,000 each 36.00 each $13,500,000

River Crossing 750,000 each 5.00 each $3,750,000

Bridge Crossings 100,000 each 117.00 each $11,700,000

Rights-of-way Non Orchard 10,000 acre 1,045.4 acres $10,453,963

Orchard 20,000 acre 193.9 acres $3,878,787

Sub-total $303,046,361

Adjusted Subtotal to Year 2000 119% $360,625,170

Construction Contingency 20% $72,125,034

Subtotal Construction Cost $432,750,204

Contractors Profit and Overhead 11% $47,602,522

Engineering and Administrative 14% $60,585,029

TOTAL $540,937,755

6/21/94 Table 4 Capital Costs for Alternative No.3

Item Unit Price Quantity Cost $ Unit

Concrete Pipe 3.25 in-dia-ft 66,320,400 in-dia-ft $215,541,300

Trench Dewatering 5,000 miles 33.9 miles $169,697

Connection to Caballo 1,000,000 each 1 each $1,000,000 Reservoir

Plant Connections 300,000 each 5 each $1,500,000

River Crossing 350,000 each 3 each $1,050,000

Rights-of-way Non Orchard 10,000 acres 371.4 acres $3,714,414

Orchard 20,000 acres 9.2 acres $183,707

Sub-total $223,159,118

Adjusted Subtotal to Year 2000 119% $265,559,350

Construction Contingency 20% $53,1l1,870

Subtotal Construction Cost $318,671,220

Contractors Profit and Overhead 11% $35,053,834

Engineering and Administrative 14% $44,613,971

TOTAL $398,339,025

6/21/94 1 For quick reference, the total capital costs for the different alternatives are 2 summarized below:

3

Capital Cost Alternative 1 $332,020,030 Alternative 2 $376,542,277

Alternative 2a $540,937,755 Alternative 3 $398,339,025

4

5 Water Conveyance Costs

6 In order to assist in evaluating project alternatives, the cost that may be 7 assigned to the conveyance of water was determined in the fonn of a cost per 8 unit volume of water delivered. In the detennination of this cost, a total 9 release to the Rio Grande Project of 650,000 ac-ft, which corresponds to an 10 "average" year, was used as the basis for the unit conveyance cost 11 calculations. This total volume was distributed among Elephant Butte l2 Irrigation District (EBID), El Paso County Water Improvement District # 1 13 (EPCWID#l), and Mexico. From the total annual amount, 60,000 ac-ft were 14 allowed for Mexico's entitlement, and of the remainder, 57 percent was used -15 as EBID's allotment and 43 percent as EPCWID#l 's. Conveyance costs were 16 determined for each one of the alternative conveyance objectives under study. 17 Capital costs were uniformly distributed over an assigned useful life of the -18 project of 50 years, with zero salvage at the end of this period. Annual O&M 19 costs were used as specified in the Cost Basis Memorandum.

-20 In order to take into account variations in demands during the life of the 21 project, the study was divided into three periods of operation: 2005 to 2014, 22 2015 to 2034, and 2035 to 2054. Alternative 1 delivers the constant volume -23 corresponding to EPCWID# 1 and a small and varying amount during each 24 period for M&I uses in Southern Dona Ana County, New Mexico. This is 25 necessary to confonn with the service area of the Anthony Regional plant as -26 currently conceived. Alternative 2 delivers a constant annual volume through 27 the life of the project, and Alternative 3 delivers a varying amount for 28 treatment by EPWU, determined on the basis of projected production -29 requirements from the existing and proposed water treatment plants. Results 30 of average-year deliveries and unit cost calculations are presented in Table 5.

50 1 Deliveries to both EBID and EPCWID# 1 were divided into agricultural and 2 M&I uses for the purpose of determining the annual costs for each particular 3 use. For M&I uses, EBID was considered to supply New Mexico users and 4 EPCWID#1 Texas users, including EPWU. Deliveries to each agency and for 5 each use, and the conveyance costs for each annual volume delivered are 6 presented in Table 6.

7 In Alternative I, the annual volumes delivered for Mexico and for EPCWID# 1 8 are constant through the 50 year life of the project, and there is a variation 9 only in the volume delivered for M&I uses in Southern New Mexico. Of the 10 constant annual volume delivered for EPCWID# I, a portion that varies with -11 time is delivered to EPWU for M&I water supply, and the complement is 12 distributed by EPCWID#1 for agricultural uses. As mentioned previously, 13 volumes for EPWU were determined on the basis of maximum production of -14 the existing and proposed water treatment plants. For the years 2005 and 15 2015, daily demand hydrographs, with a maximum limit equal to the available 16 treatment plant capacity for each year, were integrated to determine the annual -17 volume required. For 2035, it was considered that supply would occur at a 18 rate equal to average demand minus a small calculated amount drawn from 19 natural aquifer recharge throughout the year, with excess water during periods -20 oflow demand being stored through water banking in the area aquifers. The 21 volumes thus determined for each year were used to estimate average required 22 deliveries during each of the periods considered.

23 In Alternative 2, the volume delivered is the total of the Rio Grande Project 24 water. Deliveries to EBID, Mexico, and EPCWID#1 are constant through the 25 life of the project. Water for M&I uses from the EBID delivery varies in 26 volume for each period as demand in Las Cruces and Southern New Mexico 27 increases. Total deliveries to EPCWID#1 are the same as for Alternative I, 28 and the amounts for M&I uses delivered to EPWU are determined on the same 29 basis as for Alternative l.

30 In Alternative 3, all the water conveyed is for EPCWID#I to be delivered to -31 EPWU for M&I uses, and for Mexico. The volumes required by EPWU are 32 determined on the same basis as and are thus identical with those determined 33 for Alternatives 1 and 2.

51 Table 5 Water Conveyance Unit Cost

Alternative No. I Total Annual Annual Annual Average Annual Unit Cost Operation Period Capital Cost Capital Cost O&MCost Total Cost Delivery, AC-Ff per AC-Ff

I $332,020,030 2005 TO 2014 $21,064,774 $415,000 $21,479,774 318,850 $67.37 2015 TO 2034 $21,064,774 $415,000 $21,479,774 320,530 $67.01 2035 TO 2054 $21,064,774 $415,000 $21,479,774 342,155 $62.78

2 $376,542,277 2005 TO 2054 $23,889,456 $415,000 $24,304,456 650,000 $37.39

2a $540,937,755 2005 TO 2054 $34,319,410 $640,000 $34,959,410 650,000 $53.78

3 $398,339,025 2005 TO 2014 $25,272,335 $283,000 $25,555,335 196,220 $130.24 2015 TO 2034 $25,272,335 $283,000 $25,555,335 248,535 $102.82 2035 TO 2054 $25,272,335 $283,000 $25,555,335 281,805 $90.68

Notes: Annual Interest Rate: 6.00 Percent Amortization Period: 50 Years Table 6 Annual Water Conveyance Cost

Average Year Average-Year Deliveries, AC-Ff Annual Conveyance Costs Alternative No.1 Unit Cost EBID MEXICO EPCWlD#l EBID MEXICO EPCWlD#l Operation Period Per AC-Ff Al!:riculture M&I AG.IM&I Al!:riculture M&I Al!:riculture M&I AG.IM&I Al!:riculture M&I 1 2005 TO 2014 $67.37 N/A 5,150 60,000 117,480 136,220 N/A $346,937 $4,041,984 $7,914,204 $9,176,650 2015 TO 2034 $67.01 N/A 6,830 60,000 65,165 188,535 N/A $457,701 $4,020,798 $4,366,922 $12,634,353 2035 TO 2054 $62.78 N/A 28,455 60,000 31,895 221,805 N/A $1,786,345 $3,766,674 $2,002,301 $13,924,453

2 2005 TO 2014 $37.39 309,300 27,000 60,000 117,480 136,220 $11,565,182 $1,009,570 $2,243,488 $4,392,750 $5,093,466 2015 TO 2034 $37.39 301,350 34,950 60,000 65,165 188,535 $11,267,920 $1,306,832 $2,243,488 $2,436,615 $7,049,601 2035 TO 2054 $37.39 242,875 93,425 60,000 31,895 221,805 $9,081,453 $3,493,298 $2,243,488 $1,192,601 $8,293,615

2a 2005 TO 2014 $53.78 309,300 27,000 60,000 117,480 136,220 $16,635,301 $1,452,160 $3,227,022 $6,318,510 $7,326,417 2015 TO 2034 $53.78 301,350 34,950 60,000 65,165 188,535 $16,207,720 $1,879,741 $3,227,022 $3,504,815 $10,140,111 2035 TO 2054 $53.78 242,875 93,425 60,000 31,895 221,805 $13,062,718 $5,024,743 $3,227,022 $1,715,431 $11,929,495

3 2005 TO 2014 $130.24 N/A N/A 60,000 N/A 136,220 N/A N/A $7,814,291 N/A $17,741,044 2015 TO 2034 $102.82 N/A N/A 60,000 N/A 188,535 N/A N/A $6,169,433 N/A $19,385,902 2035 TO 2054 $90.68 N/A N/A 60,000 N/A 221,805 N/A N/A $5,441,068 N/A $20,114,267

Notes: Annual Interest Rate: 6.00 Percent Amortization Period: 50 Years

6/22/94 Regional Water Treatment Plants

1 Treatment of surface water and the necessary major treated water 2 transmission lines were evaluated for both the New Mexico and Texas 3 portions of the Mesilla Valley. It was determined that two regional water 4 treatment plants should be analyzed. The first, hereafter referred to as the Las 5 Cruces Regional Treatment Plant, would serve the northern portion of the 6 Mesilla Valley from Leasburg Dam to a service boundary between Santo 7 Tomas and Mesquite as shown in Figure 23. The other, hereafter referred to 8 as the Anthony Regional Treatment Plant, would serve the southern portion of 9 the Mesilla Valley both in New Mexico and Texas as shown in Figure 24.

10 Rio Grande Project Water Supply

11 The Rio Grande Project water supply is governed by the Rio Grande 12 Compact, an interstate compact that allocates the waters of the Rio Grande 13 above Fort Quitman, Texas, between the states of Colorado, New Mexico, 14 and Texas. The Compact specifies a normal release of 790,000 af annually 15 from the Rio Grande Project. However, reservoir operation studies (Reference -16 5) show that the project can currently supply an average of between 600,000 17 and 650,000 af annually with maximum supplies exceeding 790,000 af 18 annually and minimum supplies not less than 315,000 afannually. A more -19 detailed analysis of the Rio Grande Project water supply is contained in the 20 Phase I report (Reference 4).

-21 The Rio Grande Project is a federal reclamation project and its water supply is 22 also governed by federal contracts between the United States and two 23 irrigation districts, the EBID and the EPCWID#l. The EBID holds the -24 contract water rights for water delivered in New Mexico while the EPCWD#l 25 holds the contract water rights for water delivered in Texas. These two 26 districts are the contractors and managers of the Rio Grande surface water -27 supply and will play an important role in the development of the M&I surface 28 water supply.

-29 Future Population and Water Demand

30 Water demand projections were based on projected demand per capita and _31 population projections. The population projections for the Mesilla Valley, 32 from the Leasburg Dam to the New Mexico - Texas border, were derived from 33 1990 census data. The 1990 Census divided Dona Ana County into seven _34 census divisions (Figure 25). It was assumed that the population of the census 35 divisions that include the Mesilla Valley were concentrated within the

54 Leasburg /l.' /) ... Le:SbUrg ,", .. ~ , \ ~

Ana

o 9 MU ••

(APPllOXJJ(A 1'8)

BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 23 LAS CRUCES WATER TREATMENT PLANT REGION

0=\72404t\lCREGN.DGN R04 OS.2Oe4 Berino

Dona Ana County La

El Paso County

• Ii MU •• I (APPJIC)XIIUTI)

BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 24 ANTHONY TREATMENT PLANT REGION

Ot\724G4a\MTtRGH.DGN ROJ 08.2Q,84 L I r II l, .'ALIIi if \L. WHITE UI_. SANDS f tb \1 DIVISION '\ \ :; \1 HATCH \ ~7' L.., DIVISION ~ . \ ~ 'to L t'f).~ _,..., ~ 7' I

UDrD mJ. c...... __ -\ '<...... ~ ~~~ L.. ---...... \It. ,(,-, '\ II \.""'" /-...&..rl " ..... ~ -LAS CRUCES1 FAIRACRES ' -,," . DIVISION 1 DIVISION PICACHO. ~••.. . ~J.lI CRuces r --' rMRA,"'., . .~ ,

l ..mLA~ 1

\ • TOafUOO I ...... - /" -- ~""~::\\~"1 -\ I "~_\JIft I ,~ \ ... -. ,.~... 1 ~~ / \ ~_/ }. ....J~--- ...... \ ANTHONY DIVISION

SOUTH DONA ANA DIVISION

BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 25 o 10 DONA ANA COUNTY SCALE-- --IN -IIILES - CENSUS DIVISIONS

0=\72404S\DGH\C[NSUS1.DGH R01015.1CU4 I EBID boundary. The 1990 Census also provided population figures for the 2 "incorporated areas" in Dona Ana County. Incorporated areas outside of the 3 EBID boundary were not included in the projections. Average annual growth 4 rates of2.5 percent for the City of Las Cruces and 2.8 percent for the rest of 5 the EBID area were assumed through the year 2035. The two planning 6 horizons used for this study were the years 2015 and 2035. Using the above 7 assumed growth rates, the following population projections for New Mexico 8 south of the Leasburg Dam were calculated.

9 10 Table 7 -11 Mesilla Valley Population, New Mexico 12 Year Population 2015 242,738 2035 410,337

13 The population projections for the Mesilla Valley, from the Texas - New 14 Mexico border to the American Dam, were calculated based on information 15 from Boyle Engineering Corporation. Boyle predicted that the Texas 16 population in the Mesilla Valley would require 90 million gallons per day 17 (MGD) (40 MGD from a water treatment plant and 50 MGD from wells) in 18 the year 2015. A population was calculated for 2015 using the 90 MGD, a 19 2.0 peaking factor, and a 160 gallons per capita per day (gpcd) daily use. 20 Although the expected annual growth rate for the City of El Paso is 2.1 21 percent, as specified in the Criteria Memorandum (Appendix A), the 22 population served from the Anthony plant will probably grow at a faster rate. 23 This assumption is based on available land area and planned future capacity 24 at the existing Canal Street and Jonathan W. Rogers Water treatment plants 25 and expected rapid growth on the west side ofEI Paso. The 2035 capacity 26 expected at the two existing plants was subtracted from the expected overall 27 growth in El Paso. The Anthony Plant capacity for El Paso is assumed to be 28 equal to the amount of water necessary to supply this demand deficit. It turns 29 out that a service area growth rate of2.8 percent for that portion of demand to 30 be supplied from the Anthony plant corresponds to these assumptions. Using 31 this growth rate, the following population projections for the Texas portion of -32 the Anthony Plant were calculated. 33 34 Table 8 -35 Mesilla Valley Population, Texas 36 Year Population 2015 281,250 2035 488,602

58 1 The projected populations were divided into two areas, the area to be served 2 by the proposed Las Cruces regional water treatment plant and the area to be 3 served by the proposed Anthony regional water plant. It was decided that the 4 service boundary between the two regional water treatment plants would be 5 between Santo Tomas and Mesquite. Based on this boundary, the projected 6 populations that the proposed regional water treatment plants would serve in 7 the years 2015 and 2035 are: 8 Table 9 9 Water Treatment Plant Region Populations 10 11

Water Treatment Plant Year Population Served Las Cruces 2015 181,881 Las Cruces 2035 304,613 Anthony 2015 342,107 Anthony 2035 594,326 12 The above population projections were used to develop water demand 13 projections. The study assumed the following daily per capita use rates for _14 the region for the years 2015 and 2035: 15 16 Table 10 17 Mesilla Valley Projected Daily Per Capita Water Use 18 Location Year Daill:: Use (gtlcd) City of Las Cruces 2015 160 Rest of New Mexico 2015 100 Texas 2015 160 City of Las Cruces 2035 160 Rest of New Mexico 2035 160 Texas 2035 160

19 The study anticipates, for the sizing of treatment plants, that the ratio of the 20 maximum-day water supply capacity to the average-day demand will be 1.0 -21 for the entire Mesilla Valley in 2015. Maximum day demands above the 22 average demand rate are assumed to be met by pumping ground water from 23 wells. By the year 2035, the peaking factor on the water treatment plant -24 capacity will be increased to 1.5 for New Mexico outside of the City of Las 25 Cruces. This assumption was made to assure that surface water treatment 26 capacity will be adequate if groundwater production capacity for peaking is -27 limited. Las Cruces surface water treatment capacity will remain at 1.0 times 28 average demand. It was assumed that the City of Las Cruces would have

59 1 sufficient water rights, and well capacity, to meet its maximum demand with 2 ground water. The assumption that Texas would also have sufficient well 3 capacity to meet maximum demands was made; thus, Texas was also assumed 4 to have a maximum surface water production to demand factor of 1.0 through 5 2035. In order to maintain long term capacity in the Hueco Basin and 6 overdrafted parts of the Mesilla Basin, aquifer storage and recovery, discussed 7 later in the report, will be necessary. In addition to meeting the New 8 Mexicoffexas population demands, the Anthony regional water treatment 9 plant was also sized to provide Mexico with its allotted 60,000 afper year 10 (53.5 MGD) of Rio Grande water as treated water. Based on this criteria, the 11 sizes of the water treatment plants required to meet these water demands for 12 the years 2015 and 2035 are as follows:

13 Table 11 -14 Regional Water Treatment Plant Capacities 15 Water Treatment Plant Year Size (MGD) Las Cruces 2015 25 Las Cruces 2035 60 Anthony 2015 105 Anthony 2035 160

-16 Estimation of Ultimate Demand

17 In regional water supply planning, it is important to consider and evaluate the 18 ultimate water supply delivery which might be needed with total municipal 19 development of all lands in the study area. Evaluation of the ultimate system 20 provides the planner a perspective as to the water treatment and delivery 21 facilities that might eventually be needed as an area develops. With this 22 perspective, the interim plan for water supply facility needs anticipated within 23 a shorter planning horizon will be more easily updated to meet the ultimate 24 demand that may eventually be placed on the system.

25 The largest possible surface water supply system would deliver all surface 26 water as treated water for M&I uses within past or present irrigated areas of -27 the Rio Grande Project in the Mesilla Valley and other adjoining lands. Thus, 28 for the ultimate system, it is assumed that all Rio Grande Project lands in the 29 Mesilla will be developed for M&I use and the entire water supply could -30 eventually be converted from irrigation to domestic use and supplied to the 31 developed project lands. This is not to say that over the foreseeable future this 32 will actually happen. The production of food and fiber could eventually be -33 considered more beneficial than municipal developments. It is useful, however,

60 1 to ponder the ultimate water treatment demands which would result from total 2 conversion to domestic use.

3 It was assumed that the ultimate demand on the surface water supply system 4 will be constrained by the surface water supply available from the Rio Grande 5 Project. The lands that can be supplied include all Rio Grande Project lands 6 within the study area and additional lands assumed to be located along the 7 fringes of the presently irrigated area. The available surface water supply 8 from the Rio Grande Project varies from year to year, but can be depended 9 upon to deliver a base supply each year and can be supplemented with 10 recharge of surface water into the groundwater system in wet years and -ll subsequent groundwater withdrawals in low water years. This will provide a 12 sustainable and renewable water resource for the area without mining the 13 ground water aquifers.

14 The Rio Grande Compact provides for a normal release of 790,000 af 15 annually from the Rio Grande Project. For the purposes of evaluating the _16 design of the ultimate system, a 790,000 acre-foot release was used as a basis 17 for estimation of the ultimate demand on the water supply system since this 18 supply is the amount provided for the project by the Compact. The Bureau of _19 Reclamation reports that there are 177,992 irrigated acres in the Rio Grande 20 Project (Water and Power Resources Service, 1981). The Project must 21 deliver 60,000 afto the country of Mexico as part ofan international treaty 22 leaving a supply of 730,000 afannually for the project or 4.101 afper acre. 23 This water supply was used for facilities sizing at ultimate buildout.

- 24 Treatment Processes

25 The purposes of this section are to present preliminary recommended 26 treatment processes and to describe the basic information, criteria, and 27 guidelines that were used in developing the flow processes for the Las Cruces 28 and Anthony Water Treatment Plant Alternatives. The treatment processes _29 selected were based upon the information found in the Jonathan W. Rogers 30 Water Treatment Plant Predesign (JWRWTP) Report (Reference 24), water 31 quality data reported in the New Mexico State Bulletin No. 064, New Mexico 32 State University (Reference 15) as "water quality from the Rio Grande at 33 Caballo Reservoir," criteria of the American Water Works Association Water 34 Treatment Guidelines (Reference 25), the Texas Natural Resource 35 Conservation Commission Rules and Regulations (Reference 26) for public --36 water systems, and engineering experience gained on similar designs for 37 similar types of water. A description of the expected raw water quality, the 38 treatment water quality goals, and the treatment process selection follows.

61 1 Raw Water Quality

2 The sole source of raw water for the Las Cruces, New Mexico, and the 3 Anthony, Texas Regional Water Treatment Plants is surface water from the 4 Rio Grande Project as diverted into an open lined canaI or a closed conduit 5 conveyance system at or near Caballo Reservoir in New Mexico. In contrast, 6 the JWRWfP was designed to treat water, 50 percent of which comes from 7 the Rio Grande as diverted from the Riverside Canal and 50 percent of which 8 comes from the effluent of the Haskell Wastewater Treatment Plant. A very 9 conservative treatment process train would result if the complete treatment 10 criteria for the JWRWTP were used for the Las Cruces and Anthony regional 11 plants. It does not appear that such a conservative approach is necessary for 12 water that is released directly from Caballo Reservoir. Therefore, the flow 13 processes have been modified to reflect the expected better quality of water 14 released from Caballo Reservoir. Certain specific assumptions were made 15 based upon the limited information on water quality that was available. The 16 available water quality information is summarized in Table 12. None of the 17 water quality parameters shown in Table 12 exceeds the current National 18 Primary Drinking Water Regulations.

-19 The raw water conveyed to the treatment plants in lined conveyance facilities 20 will be isolated from the Rio Grande and will not contain flood flows or return 21 flows from irrigation. Thus, the raw water will contain very little sediment -22 and the water delivered to the treatment plants should have quality similar to 23 historical releases from Caballo Reservoir. In fact, the water quality of 24 releases from Caballo Reservoir is expected to be somewhat improved over -25 historical conditions due to recent changes in reservoir operations. A water 26 conservation program has been implemented by the Bureau of Reclamation 27 and the Irrigation Districts. The storage in Caballo Reservoir is now limited to -28 about 60,000 af during the hot summer months. This decreases the 29 evaporation loss from that which has historically occurred. This reduction 30 from 200,000 afto 60,000 afofstorage in the summer is expected to result in -31 less concentration of salts and a general improvement in the water quality of 32 Caballo Reservoir releases as compared to that of historical releases.

_33 On the basis of the data in Table 12 it appears that the treatment processes at 34 the Las Cruces and the Anthony regional water treatment plants can be largely 35 conventional processes for removal of turbidity, tri-halomethane precursors, _36 and other pollutants expected in a fairly high quality raw water supply The 37 information that is shown in Table 12 with regard to organics is all that was 38 available in the existing data. Much more study is needed on this issue to _39 fully determine how much removal of organics will be required.

62 Tabl.ll Water Quality In Caballo Reservoir Rei.....

Item UnitB Jan Feb Apr JIDI Jul Aug Sop Ocl Nov Calcium High 15.40 79.40 126.00 132.40 110.40 102.00 94.40 93.20 92.20 99.20 91.60 94.20 Low 44.40 37.80 51.40 59.60 55.10 49.10 38.00 49.60 53.10 48.00 52.10 51.00 Avonae 64.90 51.60 92.20 96.00 13.10 75.90 66.20 71.40 73.00 73.60 72.20 76.10

31.60 11.30 26.90 28.10 30.20 25.40 22.50 2UO 26.40 35.40 33.70 35.10 11.90 11.30 11.20 11.10 11.10 10.70 10.60 9.60 10.60 9.60 11.30 11.70 25.20 21.30 19.00 19.60 20.60 11.10 16.60 15.60 II.SO 22.50 22.50 23.40 Sodium High mgIL 252.50 259.00 212.80 177.10 235.50 175.00 162.40 175.00 223.10 265.20 274.90 263.40 Low mgIL 69.90 62.30 51.20 55.70 56.60 50.10 39.30 39.10 46.50 57.00 59.10 64.20 Average mgIL 161.20 160.70 135.50 116.10 116.10 112.60 100.90 107.10 134.80 161.10 167.40 163.10 Bi-CMbonate High mgIL 234.00 219.90 96.00 96.30 118.50 99.00 93.00 95.10 202.10 216.30 235.50 220.50 Low mgIL 69.30 72.90 74.10 74.10 66.00 66.00 52.50 71.40 40.50 66.30 77.10 75.30 Average mgIL 151.70 146.40 15.10 85.20 92.30 82.50 72.80 83.30 121.70 141.30 156.30 147.90

High 2.41 1.24 2.41 J.l6 2.48 J.l6 J.l6 1.24 2.41 4.34 J.l6 0.62 Low 0.62 0.62 0.62 0.62 0.62 0.62 0.62 0.62 0.62 0.62 0.62 0.62 Avonae 1.55 0.93 1.55 1.24 1.55 1.24 1.24 0.93 U5 2.48 1.24 0.62 Cloride High 193.47 197.D2 239.63 172.89 227.20 142.00 131.35 195.25 174.66 209.45 207.68 204.13 Low 4U3 38.70 31.95 30.17 35.15 30.53 28.40 30.17 33.72 39.05 42.60 44.02 Average 117.50 117.86 135.79 10U3 13U3 16.27 79." 112.71 104.19 124.25 125.14 124.01 Sulfate High 237.12 261.60 394.56 459.84 425.76 417.12 360.48 291.36 426.72 373.44 320.64 275.52 Low 149.28 125.76 120.48 122.88 126.24 124.32 122.88 123.36 114.72 129.60 126.24 136.80 Average 193.20 193.68 257.52 291.36 276.00 270.72 241.68 207.36 270.72 251.52 223.44 206.16 Boron High mgIL 0.31 0.29 0.28 0.25 0.26 0.21 0.20 0.22 0.26 0.36 0.30 0.21 Low mgIL 0.05 0.09 0.08 0.01 0.06 0.05 0.08 0.03 0.05 0.08 0.09 0.09 Average mgIL 0.11 0.19 0.11 0.17 0.16 0.13 0.14 0.13 0.16 0.22 0.20 0.19

A_age 0.00 0.01 0.01 0.00 0.01 CacImiwn <.006 <.006 <.006 <.006 <.006 Zinc 0.03 <.02 0.03 <'02 <.02 Mercwy <'0002 0.00 0.00 0.00 0.00 Copper <.10 <.10 <'10 <'10 <.10

4.10 0.00 0.00 0.00 0.00 Total Phosphorus 0.03 0.02 0.11 0.01 0.07 Potassium 6.30 6.20 5.50 5.10 6.60 Coliform Average Avgcnll 13.00 210.00 340.00 600.00 1,400.00 Fecal Coliform 100 mI Average Avgcnll 17.00 0.00 1,520.00 67.00 200.00 Chemical Oxygen 100ml Demand Average mgIL 16.00 36.00 44.00 87.00 28.00 PH High 8.30 1.00 8.10 8.20 8.20 8.30 1.20 8.30 8.30 8.10 8.20 8.20 Low 7.10 7.70 7.70 7.90 7.90 7.80 7.40 7.70 7.80 7.70 7.80 7.90 Average 1.05 7.15 7.90 8.05 1.05 1.05 7.80 8.00 8.05 7.90 8.00 8.05 EC High E-6 mmh.. 1,610.00 1,590.00 1,650.00 1,5SO.00 1,630.00 1,440.00 1,310.00 1,440.00 1,300.00 1,730.00 1,710.00 1,670.00 Low E-6 mmh.. 701.00 658.00 647.00 639.00 637.00 562.00 482.00 503.00 573.00 617.00 108.00 681.00 Average E-6mmh.. 1,155.SO 1,124.00 1,148.50 1,094.50 1,133.50 1,001.00 896.00 971.50 936.50 1,173.50 909.00 1,175.SO IDS High 981.00 974.00 1,069.00 1,099.00 1,040.00 981.00 885.00 914.00 1,010.00 1,062.00 1,062.00 1,040.00 Low 457.00 428.00 406.00 406.00 406.00 369.00 325.00 325.00 314.00 406.00 428.00 443.00 Average 719.00 701.00 737.50 752.50 723.00 675.00 605.00 619.50 697.00 734.00 745.00 74UO 1 The available infonnation listed in the above table did not include any data on 2 ammonia levels that might be expected in the raw water. Ammonia is a source 3 of concern relative to effective final disinfection. Therefore, the JWRWTP 4 plant design criteria for disinfection were used as a guide. This would meet 5 the goals of the EPWU with regard to residual chlorine in the complete 6 system.

7 Treatment Water Quality Goals

8 The water quality goals of JWRWTP Treatment Predesign Report were 9 adopted for this study. Consideration was also given to changes in existing 10 and expected Safe Drinking Water Act (SDWA) requirements which have 11 developed since 1990. The treatment processes must produce potable water 12 which complies with the current SDWA including current regulations 13 regarding maximum contaminant levels (MCLs). In addition, the plant 14 processes should be sized and designed to handle future more stringent 15 requirements expected under Safe Drinking Water Act regulations, where it is 16 possible to anticipate such requirements. Table 13 presents a summary of 17 infonnation regarding existing and anticipated requirements of the SDW A.

- 18 The treated water design goals of JWRWTP were developed on the basis of 19 the current and proposed state and federal regulations and on non-regulated 20 water quality concerns. These goals have been reviewed and found to be very - 21 applicable for the Las Cruces and the Anthony regional water treatment 22 plants. Therefore, they were adopted for this study.

- 23 Regulatory Objectives

24 The following is a brief discussion of regulatory objectives for water quality - 25 parameters that are currently anticipated to be regulated under the SDWA and 26 subsequent amendments. Some of the proposed regulations are expected to 27 change before being adopted since they are in the process of development at - 28 the present time. The water quality objectives presented here are based on the 29 best infonnation that is available at the present time. The following sections 30 summarize the anticipated treatment objectives.

31 Turbidity

- 32 The current SDWA regulations require water turbidity coming from the filter 33 eflluent to be less than 1 nephelometric turbidity unit (NTU). This standard is 34 proposed to be reduced to approximately 0.5 NTU. The new plants should be -35 designed to comply with the more stringent 0.5 NTU standard.

64 1 Tri-halomethanes

2 The MCL standard for tri-halomethanes (THMs) is currently 0.10 milligrams 3 per liter (mg/l). This standard is presently under consideration and will 4 probably be reduced to 0.04 mg/l. EI Paso City's older plants have previously 5 treated Rio Grande water with resulting THM levels excee,ding 0.10 mg/l at 6 times. Although THM precursors should be much lower in the Caballo 7 supply, prudence would indicate that THM control should be considered. 8 Ozonation is recommended to remove some of the organics and tri­ 9 halomethane precursors that may be in the water released from Caballo 10 Reservoir.

11 Pathogens

12 The SDWA disinfection requirements call for a 3-log removal and/or 13 inactivation of Giardia cysts. A 2-log cyst removal credit is given for a water 14 treatment plant that includes filtration and produces a filtered water less than 15 0.5 NTU in 95% of the monthly measurements. The remaining I-log Giardia 16 cyst reduction would need to be obtained through disinfection. This level of 17 removal is expected to be required for the Las Cruces and Anthony Treatment 18 Plants.

-19 Lead and Corrosion Control

20 The control of lead was adopted under the reference 56 FR 26460 dated June 21 7, 1991. This rule specifies that the water supply must not be corrosive to 22 lead and copper in consumer plumbing. Levels in the higher 10 percent of 23 consumer tap samples above 0.015 mg/l trigger public notification and 24 corrosion control requirements. As one of the means of controlling this 25 problem, a minimum pH of 8.0 is suggested for the water in the distribution

65 Table 13 Current and Expected SDW A Requirements Proposed Proposed Parameters MCL! MCLG2 MCL MCLG

Inorganic Compounds

Aluminum Antimony 0.006 0.006 Arsenic 0.050 0.050 .002 to 0.020 Asbestos 7.1E+06 Fibers/l Barium 2.0 2.0 Beryllium 0.004 0.004 Cadmium 0.005 0.005 Chromium 0.01 0.01 Copper 1.30 £ Cyanide 0.2 0.2 Fluoride 4.000 4.000 Lead 0.015 £ Mercury 0.002 .002 Molybdenum Nickel 0.1 0.1 Nitrate 10.000 10.000 Nitrite 1.000 1.000 Selenium 0.050 0.05 Silver 0.050 Sodium Sulfate 400/500 400/500 Thallium 0.002 0.0005 Vanadium Zinc

Microbiological

Coliform 1-4Clfm! o 100ml Giardia Lamblia o Legionella Standard Plate Count Viruses o

- ~CL as defined by the SDWA ~mum Contaminent Level Goal (MCLG), nonenforceable health goal, as defined by the SDWA 'iead and Copper have "action levels" requiring public information and corrosion control, which are not actual MCLs.

Notes: All values are milligrams per liter (mgll) unless otherwise stated. Under 1122/88 changes column, + indicates adition to the list, - indicates deletion pCiIl == pico-Curie per liter, mremlyear == millirem per year, N1U == nephelometric turbiduity unit Table 13 (continued) Current and Expected SDWA Requirements

Proposed Proposed Parameters MCV! MCLGQ MCL MCLG

Synthetic Organic Compounds

1,2-Dichloropropane 0.005 0 0.006 2,3,7,8-TCDD (Dioxin) 2,4,5-TP Silvex 0.05 0.05 0.052 2,4-D 0.1 0.07 Acrylamide 0 Adipates 0.4 0.4 Alachlor 0.002 0 0 Aldicarb 0.003 0.001 Aldicarb Sulfone 0.002 0.001 Aldicarb Sulfoxide 0.004 0.001 Atrazine 0.003 0.003 Carbofuran 0.04 0.04 Chlordane 0.002 0 Dalapon 0.2 0.2 Dibromochloropropane 0.002 0 Dibromomethane Dinoseb Diquat Endothall Endrin 2.0E-04 Epichlorohydrin 0 Ethylbenzene 0.7 0.7 Ethylene Dibromide 0.00005 0 Glyphosate Heptaclor 0.0004 0 Heptaclor Epoxide 0.002 0 Hexachlorocyclopentadiene Lindane 0.0002 0.0002 Methoxyclor 0.04 0.04 Pentachlorophenol 0.001 0 Phthalates 0.006 0 Pichloram 0.5 0.5 Polychlorinated Biphenyls 0 Polynuclear Aromatic Hydrocarbons aMCL as defined by the SDWA ~mum Contaminent Level Goal (MCLG), nonenforceable health goal, as defined by the SDWA

Notes: All values are milligrams per liter (mgll) unless otheIWise stated. Under 1122/88 changes column, + indicates addition to the list, -indicates deletion pCi/1 = pico-Curie per liter, rnremlyear = millirem per year, NTU = nephelometric turbidity unit Table 13 (continued) Current and Expected SDWA Requirements

Proposed Proposed Parameters MCIfi MCLGQ MCL MCLG Simazine Styrene 0.1 0.1 Toluene 1.0 1.0 Total 0.100 0 Trihalomethanes Toxaphene 0.003 0 Vydate Xylenes 10 10

Volatile Organic Compounds

I, I, I-Trichloroethane 0.200 0.200 1,2-Dichloroethane 0.005 0.000 I,I-Dichloroethylene 0.007 0.007 Benzene 0.005 0.000 Carbon Tetrachloride 0.005 0.000 Chlorobenzene CIS 1,2-Dichloroethylene 0.070 Methylene Chloride P-Dichlorobenzene 0.750 0.750 Tetrachloroethylene 0.000 Trans 1,2-Dichloroethylene 0.070 Thichlorobenzene (s) Trichloroethylene 0.005 0.000 Vinyl Chloride 0.002 0.000

Radionuclides

Radon 300. pCi/l 0 Uranium 0.02 0 Gross Alpha Particle 15 pCi/l 0 Activity Radium-266 & Radium-228 20 pCi/l 0 B Particles & Photon 4 mremlyr 0 Radioactivity

Other

Turbidity 1.0NTU O.5NTU 0.1 NTU aMCL as defined by the SDW A ~mum Contaminent Level Goal (MCLG), nonenforceable health goal, as defined by the SDWA

Notes: All values are milligrams per liter (mgll) unless otherwise stated. Under 1122/88 changes column, + indicates addition to the list, - indicates deletion pCi/l = pico-Curie per liter, mremlyear = millirem per year, NTU = nephelometric turbidity unit Table 13 (continued) Current and Expected SDWA Requirements

National SMCL£ Texas SMCL!i

Maximum Secondary Contaminants

Chloride 250 300 Color (color units) 15 15 Copper 1 1 Corrosivity noncorrosive noncorrosive Fluoride 2 2 Foaming Agents 0.5 0.5 Hydrogen Sulfide 0.05 Iron 0.3 0.3 Manganese 0.05 0.05 Odor (threshold odor number) 3 3 pH 6.5-8.5 6.5-8.5 Sulfate 250 300 Total Dissolved Solids 500 1000 Zinc 5 5 cSMCL as defined by the SDWA dSecondary Maximum Contaminent Level Goal (MCLG), nonenforceable health goal, as defined by the SDWA Notes: All values are milligrams per liter (mgll) unless otherwise stated. Under 1122/88 changes column, + indicates addition to the list, - indicates deletion pCiIl = pico-Curie per liter, mrernlyear = millirem per year, NTU = nephelometric turbidity unit 1 system. Therefore, provisions to achieve this pH goal should be included in 2 the Las Cruces and Anthony plants.

3 Synthetic Organic Compounds

4 MCLs currently exist for several synthetic organic compounds. The plants as 5 proposed would not be susceptible to synthetic organic compounds from 6 pesticides from agricultural lands or from secondary effluent discharges. It 7 was assumed that crop dusting from the air near the open conveyance channel 8 would be curtailed. With this assumption, synthetic organic compounds do 9 not appear to be a problem. The use of activated carbon for the removal of 10 synthetic organic contaminants is therefore not recommended and is not 11 included in the proposed flow process.

12 Disinfection Byproducts

-13 New regulations for disinfection byproducts are expected. The compounds to 14 be regulated will include chlorinated organics produced as a byproduct of 15 disinfection with chlorine. The formation of these compounds could be -16 reduced at the proposed treatment plants by using ozonation. However, 17 ozonation also produces disinfection byproducts which may be regulated in the 18 future. For that reason, only pre-filtration ozone is suggested at the present _19 time for the new plants. This would allow chemical coagulation and 20 sedimentation to remove some of the organics prior to ozonation. Post 21 ozonation filtration should help to control some of the ozonation byproducts.

22 Policy Objectives

-23 The JWRWTP Predesign Report included Public Service Board objectives 24 and concerns for the quality of the EI Paso drinking water not mandated by 25 EPA regulations. These include softening, taste and odor control, and total _26 dissolved solid concentrations, and are discussed below.

27 Finished Water Hardness

28 The EPWU's policy is to remove hardness that exceeds 150 mgll as CaC03 29 through lime softening, as long as it does not raise the pH of the water above -30 9.3. The Caballo supply has total hardness in the 150 mgII range. Therefore, 31 it is assumed that lime softening will not be necessary in the treatment 32 processes to be designed for the two regional plants.

70 1 Taste and Odors

2 As the JWRWTP Predesign report states: "All waters have some tastes and 3 odors from minerals present in the raw water or from disinfection. There are 4 two common philosophies for taste and odor control. One is to maintain a 5 minimum level of taste and odor below a threshold concentration; the other is 6 to have no detectable objectionable tastes and odors." The EPWU bas 7 requested that the latter policy be used as the basis for design where possible. 8 It is anticipated that this policy would be used in the Las Cruces and Anthony 9 Treatment Plant alternatives. Although taste and odor may be less prevalent in 10 the Caballo supply than further down river, it would be wise to plan for -11 chemical addition facilities for taste and odor control ifnecessary and for 12 other unforeseen raw water conditions.

13 Total Dissolved Solids

14 The total dissolved solids (IDS), as shown in the available data from Table 15 12 above, showed an average ofbetween 500 and 600 mg/l. Only under 16 severe periods of drought does the IDS get above 1000 mg/l for water out of 17 Caballo Reservoir. The upper limit set by the State Health Departments for 18 both New Mexico and Texas is 1000 mg/l. Therefore, it does not appear that 19 removal of IDS will be needed in the treatment processes.

20 Final Disinfection

21 In order to assure the safety of the potable water, it is wise to maintain a free 22 chlorine secondary disinfectant residual. Therefore, this bas been included in 23 the design for the new treatment plants.

24 Process Selection

Based upon the information available for the raw water quality expected for the plants and the previous discussions, it is suggested that the treatment plant processes include the following: o Presedimentation

29 o Ferric Sulfate and Polymer Coagulation 30 o Clarification 31 o Ozonation 32 o Tri-media Filtration

71

------1 Ll Facilities for Chemical Addition at Several Locations

2 A suggested process diagram is shown in Figure 26 for these treatment plants. 3 It is anticipated that the pre-sedimentation process can be achieved in a raw 4 water reservoir just ahead of the plant. This raw water reservoir may be 5 constructed as part the existing conveyance facilities as described in the 6 regulating reservoirs section of this report. It is also anticipated that there 7 would be no pre-ozonation, but pre-filtration ozonation would be used.

8 Estimation of Treated Storage Capacity

9 Municipal water demands typically are at a minimum at night, increase to a 10 peak some time in the afternoon, and decrease again toward nighttime. It is 11 usually most economical to design treatment facilities for the peak daily -12 demand and to provide storage sufficient to supply the diurnal fluctuations 13 during the peak day. A storage requirement of30 percent of peak day demand 14 was assumed to supply the increased demand during the daylight hours of the -15 peak day. Storage is also used to provide fire protection flows, which are 16 assumed to use 30 percent of total storage. Storage for each reservoir was 17 increased by an additional one million gallons (1 MG) for fire storage.

18 Distribution System Development

-19 The distribution systems were developed using commercial computer models. 20 The alignments of the pipelines were held constant for the alternatives to allow 21 a more direct comparison of the levels of development for decision purposes -22 concerning future system improvements. The results in this report are based 23 upon available data and are to be used as guide in making decisions 24 concerning the future of regional water development. This study was -25 accomplished assuming that the water distribution system will deliver both 26 treated surface water and groundwater from the existing wells. In this level of 27 study, no information was available concerning where the wells will connect to -28 the main distribution system. It was assumed that the wells would deliver 29 water to the same supply location as the water treatment plant, or potentially 30 to the reservoirs.

31 Las Cruces Regional Treatment Plant and Distribution System

-32 This section discusses treatment of surface water and treated water 33 transmission lines in the northern portion of the Mesilla Valley. The City of 34 Las Cruces is the major municipality and lies within the central portion of the _35 study area. Potable water systems are associated with the communities within 36 the valley. All of the communities in the study area currently depend

72 "

POLYMER l'!Im I~ ZO KlInO, 'tI ~-< I F,e."'.! Z_-~ WATER 0-3_ tu;. ~Z STORAGE "'.!li::c;'l 'l'!I BASIN RAW tal'!l WATER I:""l:I:JC:: 0:0 OZ~ l'!I- PUMP :IiI0-3l:1:J ZZ STATION n~ t;:)'tIN -I I _1:""0) !'!In -0 RAPID MIX » Z:o """'7cLARIFIER c;'lZ n-o BASIN ~>-i '0 > :.:0 Ii:: ..,.. 0 SLUDGE TO -Z THICKENER THEN LAGOONS

S9. BREAKPOINT CHLORINATION POLYWER AND DECHLORINATION HjO. ,{,\{,\ MULTI-MEDIA rILTER 1: 1" TO f--o--- DISTRIBUTION SYSTEM \ \ HIGH ~I~I~I ;;L~RINFLUENT SERVICE PUMP PUMP STATION STATION O. O. O. RECHLORINATION AND PRE-FILTER CLEARWELL OZONATION BACKWASH SUPPLY STORAGE RESERVOIR BACKWASH WATER RECYCLE , Clo POLYWER 1 exclusively on a limited groundwater supply. The City of Las Cruces is by 2 far the largest supplier of municipal water in the area. Other municipal water 3 suppliers in the study area include, but are not necessarily limited to the 4 following: 5 a Jomada Water Company 6 a Moongate Water Company

7 a New Mexico State University

8 a Mountain View Water and Sewer Association 9 a Mountain View Mutual Domestic Water Consumer 10 Association

11 a Picacho Mutual Domestic Water Consumer Association 12 a Dona Ana Mutual Domestic Water Consumer Association

13 a Valley View Water Users Association -14 a Alameda Mobile Home Park Associates 15 a Holly Gardens Mobile Home Park 16 a Leasburg Mutual Domestic Water Consumer Association 17 a Silver Spur Mobile Home Park 18 a Shangri-La Trailer Park a St. John's Mobile Home Park a Mesa Development a Brazito Mutual Domestic Water Consumer Association 22 a RaasafHilis Mutual Domestic Water Consumer Association 23 a Vista Real Mobile Home Park

24 a Alto De Las Flores Mutual Domestic Water Consumer -25 Association 26 These smaller water systems generally consist of one or two wells, one or two -27 small storage reservoirs, and a limited network of smaller diameter pipelines 28 for distribution.

74 1 The City of Las Cruces currently has a population of approximately 62,000 2 people and draws its water supply from 21 active wells located throughout the 3 city. Its distribution system consists of smaller diameter pipelines, mostly 12 4 inches in diameter or less, leading from each well and generally serving the 5 lands in the vicinity of the well. Trunk lines no larger than 24-inches in 6 diameter distribute water from six storage reservoirs that provide pressure 7 head stabilization and storage for periods of peak use and fire suppression.

8 The distribution system is divided into six pressure zones the largest of which 9 is called the Low Zone. All of the lands in the Elephant Butte Irrigation 10 District in vicinity of Las Cruces would fall within this Low Zone. The Low _11 Zone is currently served by three reservoirs with a total capacity of 12 approximately 8.0 million gallons (MG) and a maximum water surface 13 elevation of approximately 4,124 feet.

14 Water Treatment Plant

-15 Surface water from the Rio Grande will require treatment before it can be 16 used for municipal purposes. The location of a water treatment plant is 17 influenced by a number of factors including, but not limited to:

18 o the central proximity to the entire service area,

19 o land development patterns, 20 o proximity to flood plains and other geologic hazards,

-21 o topography,

22 o land area requirements, -23 o cost and availability ofland, 24 o ability to return water to the river when needed, 25 o pumping requirements,

26 o preservation of water quality,

27 o size and length of raw water conveyance facilities,

-28 o size and length of finished water main lines, 29 o and politics.

75 1 After careful consideration of these factors, it is recommended that the 2 location for the Las Cruces Regional Treatment plant be south of Dona Ana 3 alongside the Dona Ana Lateral just downstream of the Dona Ana Arroyo. 4 This site offers the advantage of being centrally located within the service area 5 while preserving much of the available head or elevation. Water can be 6 spilled to the river down the Dona Ana Arroyo when required. This site is 7 also close to the foothills where storage facilities can be located to provide 8 pressure head for the delivery system. The plant can be supplied from the 9 Dona Ana Lateral of the Leasburg Canal system which diverts from the river 10 at the Leasburg Diversion Dam. However, this lateral will need to be lined 11 and enlarged for raw water delivery.

12 The plant would be located sufficiently far outside of the Dona Ana Arroyo 13 floodplain to prevent flooding of the facility. A large flood detention basin on -14 the arroyo upstream of the site provides added flood protection. The land is 15 relatively flat and suitable for the layout of a large facility.

16 Distribution System

17 The study area was divided into subareas for estimation of required pipeline ~ 18 conveyance and reservoir treated water storage capacities (see Figure 27). 19 The average day and maximum day demands were computed as shown in 20 Table 14. Maximum hour demands were assumed to be 1.75 times maximum -21 daily demands. 22 Table 14 Average and Maximum Daily Demands for Las Cruces

2035 Ultimate Average Maximum Average Maximum Demand Demand Demand Demand Reservoir Sub-Area MGD MGD MGD MGD

I 18 36 51 101 2 5 10 16 32 3 24 48 53 106 4 7 14 52 104

-23 24 Main distribution lines were designed to deliver maximum hour demands _25 within the reservoir service area and maximum day demands from the water 26 treatment plant to the storage reservoirs.

76 800STBR OIl Q -I2I1GD BIAD • 38·---t...... -~~

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 27 LAS CRUCES WATER TREATMENT PLANT TREATED RESERVOIR SERVICE AREAS Phased Development Plan for Las Cruces

2 A goal of this study was to develop a plan for providing surface water for 3 municipal development that would be as compatible as possible with the 4 current and anticipated future water system of the City of Las Cruces. The 5 phased development plan presented here can deliver treated surface water to 6 the City of Las Cruces at points designated by the 1988 Water System Master 7 Plan (Leedshill-Herkenhoff, Inc., 1988) for development of well fields. This 8 treated surface water can be delivered at pressures compatible with the 9 existing.

10 The delivery system could be constructed in phases as the need for facilities 11 arises. This also allows for modification of alignments, sizing, and phases of 12 development as data becomes available and as the future becomes more 13 clearly defined. Three main development phases are identified in this section. 14 Within each phase, construction of many of the facilities can be deferred until IS they are actually needed. The estimated construction costs presented must be -16 viewed as reconnaissance level only.

_17 2015 Facilities

18 This phase will provide treated surface water to meet the increased demand 19 expected in the Las Cruces area by the year 2015. The facilities to be 20 constructed in this phase include a 25 MGD water treatment plant, 22 MG of 21 treated water storage in reservoirs, and main lines as shown in Figure 28. The 22 treatment plant should be planned for the ultimate capacity and the necessary 23 land purchased to accommodate plant improvements and future expansion. 24 The figure shows the estimated finished water storage elevation for the 25 reservoirs constructed in this phase. Booster pump stations will be required at 26 the water treatment plant and at other locations (as shown) to deliver water to 27 the storage reservoirs during offpeak hours. In addition, the Dona Ana 28 Lateral would be concrete lined and enlarged slightly to carry the ultimate -29 capacity of300 cfs.

30 The 2015 facilities can provide treated surface water directly to the City of -31 Las Cruces and Dona Ana. The communities of Mesilla, Mesilla Park, and 32 Tortugas can be served indirectly through the Las Cruces water system; 33 however, the amount of water that can be supplied to these communities will -34 be constrained by the conveyance capacity of the Las Cruces system. The 35 2015 system would have a capacity to serve approximately 103,000 people at 36 the current per capita use for Las Cruces of242 gaVdayor 156,000 people at -37 the 160 gal/day expected target consumption. The estimated cost for the

78 I construction of the 2015 facilities is approximately $130.1 million as detailed 2 in Table IS.

3 These costs, as well as the other costs presented in the following discussions 4 of water treatment and transmission facilities, are based on unit cost values 5 from the Cost Basis Memorandum in Appendix B. The unit cost for water 6 treatment plant construction in the memorandum was based on projections of 7 costs for facilities similar to the JWRWTP in El Paso. It is, therefore, 8 conservatively high. Actual construction cost for the slightly simpler process 9 train required for the softer Caballo Reservoir supply may be somewhat less, 10 and the water treatment plant costs in Table 15, 16, 18, and 19 are probably -ll conservatively high.

12 It is expected that the water treatment plant will need to be brought on line _13 before 2015 to provide the demands projected in the 2005 planning horizon of 14 the 1988 Las Cruces Water System Master Plan. The recommended IS development for the water treatment plant and the distribution system for the __ 16 year 2005 are shown in Figure 29. The estimated cost for this development is 17 included in the cost estimate for the 2015 phase. 18 Table 15 Construction Costs for Las Cruces, 2015

Incremental Total Cost Cost Facilities $(Millionsl $(Millions)

Land 1.0 1.0 Water Treatment Plant 34.3 34.3 Distribution System 28.2 28.2 Pumps 10.8 10.8 Reservoirs 8.0 8.0 Subtotal 82.3 82.3

Construction Contingency (20%) 16.3 16.3 Construction Cost Total 98.5 98.5

Contractor Profit (12%) 11.8 11.8 Unknown Field Conditions (5%) 4.9 4.9 Engineering and Admin. (15%) 14.8 14.8

Total 130.1 130.1

79 o

BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 28 LAS CRUCES WATER TREATMENT PLANT AND 2015 DISTRIBUTION SYSTEM

O:\72404f\LC201:5R,OGH ROJ 01.20,94 1 2035 Facilities

2 Phase n facilities would provide mainlines for service to the balance of the 3 northern half of the Mesilla Valley from Santo Tomas to Leasburg as shown 4 in Figure 30. The water treatment plant would be upgraded to 60 MGD 5 capacity. This could be done more efficiently and more cost effectively if the 6 plant is planned for expansion and the necessary land is purchased as 7 indicated in the 2015 facilities. The figure shows the location of the storage 8 reservoirs, their elevations, and their necessary capacities. Additional storage 9 of 14 MG would also be needed to meet peak hour demands. Booster pump 10 stations will be required at the water treatment plant and at other locations as -ll shown in the figure. These facilities would have a capacity to serve 12 approximately 375,000 people, assuming 160 galIday/person demands. Total 13 cost of the 2035 facilities is estimated at approximately $242.1 million as -14 detailed in Table 16. This will require an additional $112.0 million additional 15 expenditure upon the completion of the 2015 facilities.

-16 Table 16 Construction Costs for Las Cruces, 2035 Incremental Total Cost Cost Facilities Millions Millions Land 0.0 l.0 Water Treatment Plant 47.8 82.1 Distribution System 12.9 41.1 Pumps 6.6 17.4 Reservoirs 3.6 1l.6 Subtotal 70.9 153.2

Construction Contingency (20%) 14.2 30.4 Construction Cost Total 85.1 183.6

Contractor Profit (12%) 10.1 2l.9 Unknown Field Conditions (5%) 4.2 9.1 Engineering and Admin. (15%) 12.6 27.4

Total 112.0 242.1

81 Leesburg De. m... ( . , J

\ Dona Ana I <.~..; RlSERVOIR I J;------) 1", .' STORAGE· ~LIIG ,-1\'" .ux, .,s. I~-'.' i !!OQI!TE':.';f, r---' . ue' .---- .L ~---., <'I!!'1"'~'r-'-""·::.'TlRP TdA'~NT PLAN", ,---_ CAPACITY f 26) MGD ,,~ • -- . "iO' -~ ~~.. f ,~~~ I ,.. "qf , ..-:~.... i i i, r-~ P cacho. i L-----1 i, r----J \ \ i~ / ... -.,:,::~~/

\\.--?(,,( stI".' ...... ,,· ,,'\. -"..•. _',.: .• !.' 0. ',.. 0. }lOut. eo \' "sui. , 'c \ \\ "'. y '\ ' l~ ..J

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 29 LAS CRUCES WATER TREATMENT PLANT AND 2005 DISTRIBUTION SYSTEM

t):\72404e'\L.C2OO&.DGN R03 06.20.14 Lea.burg ~~

BoosnR -2 Q • 12 IIOD '\ HIAD . 33'---'---\r-...::>J" i-'-'-'-- J ,

P cacho

BOOSTER o:! ~ Q • 46 IIGD: _36" HEAD .. 280'

RESERVOIR 3 STORAGS • 15 IIG MAX. W.S. ELEV .• "12,,'

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 30 LAS CRUCES WATER TREATMENT PLANT AND 2035 DISTRIBUTION SYSTEM

Ot\7240441\LC2OM.DGN R03 OS.20.~ 1 Ultimate Facilities

2 Much larger or ultimate facilities may become necessary when demands begin 3 to exceed the capacity of the previous phase delivery system. Conversion to 4 total M&I demand would increase the size of the water treatment plant to 5 roughly 190 MGD, increase the size of the storage reservoirs to a total of 107 6 MG, and require that either the pipelines be replaced to the ultimate capacity 7 requirements, or that parallel lines be run to meet the demand. Figure 31 8 shows the locations, elevations, and capacities of the storage reservoirs, the 9 diameters of the pipelines should single pipelines be built, and the locations 10 and sizes of the booster pumps necessary to deliver water to the storage -11 reservoirs. These facilities would have the capacity to serve a population up 12 to 1,200,000 people depending upon the actual per capita use.

13 Anthony Regional Treatment Plant and Distribution System

14 This section discusses treatment of surface water and treated water -15 transmission lines for the southern portion of the Mesilla Valley including 16 areas from La Mesa and Mesquite to the American Dam. The City of EI Paso 17 is the major municipality and extends northward into the southern portion of -18 the Mesilla Valley. Potable water systems are associated with other smaller 19 communities within the valley. All of the smaller communities in the study 20 area currently depend exclusively on a groundwater supply. The City of EI -21 Paso is by far the largest supplier of municipal water in the area and currently 22 treats surface water taken from the Rio Grande during irrigation season at two 23 treatment plants, the JWRWTP and the Robertson-Umbenhauer Water -24 Treatment Plant. Other municipal water suppliers in the southern Mesilla 25 Valley include, but are not necessarily limited to the following: -26 o Anthony City

27 o Las Mesa Mutual Domestic Water Consumers Association

~8 o Mesquite Mutual Domestic Water Consumer Association

29 o Westway Water Control and Improvement District

30 o Great Southwest Water Company

31 o Vinton Mobile Home Park

32 o Mayfair No.5 Subdivision -33 o La Tuna Correctional

84 Leaaburl Dam r /; . ....::::::::::::--

Dona Ana

RESIIRVOIR I STORAGa • 31 1110 MAX, .,5, ILIV,· 4124' ,----__ _

~?WRt'·t"'lAD - 8' r----'I ~JI.'---"'_'~;~TIR T AiMiHTPi.4.NT ,-----, ,- CAPACIT - iIlO MGD ... I ----- PUMP - 3,a IIGD ..." , '\ ..4/!...... BEAD • 1"'- _;,.. t.:q, ,(--' "'. .;.. 11' I ~~". , ..'" ! I i, r-~ ,i P cacho. L _____ ) , I, ~----' \ RESERVOIR 3 STOUGS - 33 KG \ lIAX .•.S. ILEV .• 4124' i- / -""":'.l' - ,~\ l', \. ,..-\ \. ',/llEsERVO[R 4 1 '( STORA.GB" 32 KG \ \ IIU .•.8. ILIV. - 4124' '''"- '\. - -\ l ,-.d .

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 31 LAS CRUCES WATER TREATMENT PLANT AND ULTIMATE DISTRIBUTION SYSTEM

Q<\124044\LCLLT,DGH R03 06.20,1M 1 o Hillside Mobile Home Park 2 o Gaslight Square Mobile Home Park 3 These smaller water systems generally consist of one or two wells, one or two 4 small storage reservoirs, and a limited network of smaller diameter pipelines 5 for distribution.

6 The City ofEI Paso's water supply lines extend northward into the study area, 7 with a 60 inch pipeline extending along the Vinton Lateral just south of the 8 water treatment plant.

9 Water Treatment Plant

-10 As indicated above, surface water from the Rio Grande will require treatment 11 before it can be used for M&I purposes. After careful consideration of siting 12 factors, the recommended location for the Anthony Regional Treatment plant -13 is on the Vinton Lateral at the junction with the Nemexas Drain. This location 14 is relatively flat agricultural land centrally located within the region as shown 15 in Figure 32. Water can be returned to the river down the Nemexas Drain -16 when required. This site is also close to Vinton Bridge for delivery to a 17 storage reservoir in the foothills east of the river to stabilize pressure head for 18 the delivery system. The plant can be supplied from the Vinton Lateral served -19 by the La Union East Lateral of the West Side Canal. However, these laterals 20 will need to be lined and enlarged for delivery of the ultimate raw water 21 demand.

22 The plant would be located sufficiently far outside of the Rio Grande 23 floodplain to prevent flooding of the facility. The land is relatively flat and 24 suitable for the layout of a large facility.

25 Distribution System

26 The study area was divided into three reservoir service areas for estimation of 27 required pipeline conveyance and reservoir storage capacities (see Figure 32). 28 The average day and maximum day demands were computed as shown in 29 Table 17. Maximum hour demands were assumed to be met totally by the 30 connecting systems.

-31 Main distribution lines were designed to deliver maximum day demands from 32 the water treatment plant and nearby wells to the connection nodes. The 33 storage reservoirs are intended for flow and pressure regulation only.

86 .~ \

Dona Ana County La

El Paso County

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 32 ANTHONY WATER TREATMENT PLANT TREATED RESERVOIR SERVICE AREAS

D:\124044\ATRSADGN R0106.20.M I Maximum hour demands would not be met by these reservoirs. Providing for 2 peak-hour demands will be the responsibility of the connecting entities. 3 Table 17 Average and Maximum Daily Demands for Anthony Plant

2035 Ultimate Average Maximum Average Maximum Demand Demand Demand Demand Reservoir Sub-Area MGD MGD MGD MGD

I 4 7 75 150 2 32 63 77 153 3 59 117 59 117 4

5 Phased Development Plan for Anthony

6 A goal of this study was to develop a plan for providing surface water for 7 municipal development that would be as compatible as possible with the 8 current and anticipated future water system of the New Mexico and Texas 9 entities. The phased development plan presented here can deliver treated 10 surface water to the existing and planned delivery systems in the region. This -ll treated surface water can be delivered at pressures compatible with the 12 existing system.

-13 The delivery system could be constructed in phases as the need for facilities 14 arises. This also allows for modification of the alignments, sizing, and phases 15 of development as data become available and as the future becomes more -16 clearly defined. Three main development phases are identified in this section. 17 Within each phase, construction of many of the facilities can be deferred until 18 they are actually needed. The estimated construction costs presented must be -19 viewed as reconnaissance level only.

20 2015 Facilities

21 This phase will provide treated surface water to meet the increased demand 22 expected in the Anthony, Texas and Anthony, New Mexico areas by the year -23 2015. The facilities to be constructed in this phase include a 105 MGD water 24 treatment plant, 44 MG of treated water storage in reservoirs, and main 25 distribution lines as shown in Figure 33. The storage reservoirs shown in the -26 figure for 2015 are the same size as for 2035. This storage will be needed to 27 stabilize the pressure and flows to Mexico and meet the expected Texas and

88 1.

, ,_~~i __ .' 'Anthony ~,.j.l,----I::-~---- c... If--; Texas , I I , YA.TlR TREATKaT PLANT ._____ ,-• __ .-J'I , CAPACITY • 10& IWD ,UIIP I o - 10& IIGD \', , l'l .. ----~---I RlAD ·18&' -I i ...... 0[ •• Dona Ana r~-~...... I'"" ~~/.=. ~.l!G816O· County La ton

El Paso County

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 33 ANTHONY WATER TREATMENT PLANT AND 2015 DISTRIBUTION SYSTEM

[):\72404e'vUOt5.DGN R02 08.20.04 I New Mexico demands. The treatment plant should be planned for the ultimate 2 capacity and the necessary land purchased to accommodate plant 3 improvements and future expansion. The figure shows the estimated water 4 storage elevation for the reservoirs constructed in this phase. Booster pump 5 stations will be required at the water treatment plant and at other locations (as 6 shown) to deliver water to the storage reservoirs during offpeak hours. In 7 addition, the Vinton Lateral should be concrete lined and enlarged slightly to 8 carry the ultimate capacity of 480 cfs or 305 MGD.

9 The 2015 facilities can provide treated surface water directly to the existing 10 Texas mainlines, provide treated water for the southern end of this region II within New Mexico, and deliver the 60,000 af of treated water at a constant 12 rate of 53.6 MGD to Ciudad Juarez at the new border crossing near Anapra. 13 The 2015 system would have a capacity to serve approximately 321,000 14 people in Texas and New Mexico at the 160 galIday expected consumption. 15 The estimated cost for the construction of the 2015 facilities is approximately 16 $310.1 million as detailed in Table 18. -17 Table 18 Construction Costs for Anthony, 2015

Incremental Total Cost Cost Facilities $CMilIions) $CMilIions) Land 2.0 2.0 Water Treatment Plant 143.6 143.6 Distribution System 23.7 23.7 Pumps 14.7 14.7 Reservoirs 12.1 12.1 Subtotal 196.1 196.1

Construction Contingency (20%) 38.8 38.8 Construction Cost Total 234.9 234.9

Contractor Profit (12%) 28.2 28.2 Unknown Field Conditions (5%) 11.7 11.7 Engineering and Admin. (15%) 35.2 35.2

Total 310.1 310.1 18

_19 It is expected that the water treatment plant will need to be brought on line 20 before 2015 to provide the demands projected in the 2005 planning horizon. 21 The recommended development for the water treatment plant and the

90 1 distribution system for the year 2005 is shown in Figure 34. The estimated 2 cost for this development is included in the cost estimate for the 2015 phase.

3 2035 Facilities

4 The 2035 facilities would provide main distribution lines for service to the 5 balance of the southern half of the Mesilla Valley from the New Mexico­ 6 Texas border to Mesquite as shown in Figure 35. The water treatment plant 7 would be upgraded to a 160 MGD capacity. This could be done more 8 efficiently and more cost effectively if the plant is planned for expansion and 9 the necessary land is purchased as indicated in the 2015 facilities. The figure 10 shows the location of the storage reservoirs, their elevations, and their 11 necessary capacities. Additional storage of 3 MG would also be needed to -12 meet peak hour demands. Booster pump stations will be required at the water 13 treatment plant and at other locations as shown in the Figure 35. These 14 facilities would have a capacity to serve approximately 665,000 people in -15 Texas and New Mexico, assuming 160 galJday/person demand. Total cost of 16 the 2035 facilities is estimated at approximately $466 million as detailed in 17 Table 19. This will require an additional $155.9 million additional _18 expenditure upon the completion of the 2015 facilities. 19 Table 19 Construction Costs for Anthony, 2035

Facilities Incremental Total Cost Cost $Millions $Millions Land 0.0 2.0 Water Treatment Plant 75.4 219.0 Distribution System 16.2 39.9 Pumps 5.6 20.3 Reservoirs 1.4 13.5 Subtotal 98.6 294.7

Construction Contingency (20%) 19.7 58.5 Construction Cost Total 118.3 353.2

Contractor Profit (12%) 14.1 42.3 Unknown Field Conditions (5%) 5.9 17.6 Engineering and Admin. (15%) 17.6 52.8

Total 155.9 466.0

91 Berino

YATER TRBJ.TlIElfT PUNT-""t-_ CAPACITY • 1M ..GD PWP HJ:'i. ~OM'GD Dona Ana County La

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC.

FIGURE 34 ANTHONY WATER TREATMENT PLANT AND 2005 DISTRIBUTION SYSTEM Dona Ana County La

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC_

FIGURE 35 ANTHONY WATER TREATMENT PLANT AND 2035 DISTRIBUTION SYSTEM ___ -----i_I ....

O:\72<4O<41~3&.DGN R02 05.20.94 Ultimate Facilities

2 Larger or ultimate facilities may eventually become necessary if demands 3 begin to exceed the capacity of the 2035 phase delivery system. This phase 4 would increase the size of the water treatment plant to roughly 305 MGD, 5 would increase the size of the storage reservoirs to a total of82 MG, and 6 would require that either the pipelines be replaced to the ultimate capacity 7 requirements, or that parallel lines be installed to meet the demand. Figure 36 8 shows the locations, elevations, and capacities of the storage reservoirs, the 9 diameters of the pipelines should single pipelines be built, and the locations 10 and sizes of the booster pumps necessary to deliver water to the storage 11 reservoirs. These facilities would have the capacity to serve a population up 12 to 1,570,000 people in New Mexico and Texas depending upon the actual per 13 capita use.

94 Berino

" .-.. ", --~ '--y '. ,Anthony ~. .J+' ----i--iTeru-- f--, , I I , 'WATIA TREATMIIM' PLANT-...... _ , I C'&PACITT • 305 "GD ,UIIP -----1---.--1 , Q • 418 ..GD Ll _----,r---J DiD· 233' -! i RUIIIY.... ilia Dona Ana !')~:r!r--.II~/~.·· _..J.' I' stoaAGIIIIAX. ".8. ILI'¥'.·••7 3800' County La ton

El Paso County

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BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE. INC.

FIGURE 36 '0 'qourcll.. t:. Bridle ANTHONY WATER TREATMENT PLANT AND - ....,..c:..-.J./ ULTIMA TE DISTRIBUTION SYSTEM

1):\72404e\AULT.DGH R02 0&.20.14 Water Budget Analysis

1 Introduction

2 In order to assess the impacts of the three proposed alternatives on the Rio 3 Grande hydrologic system, water budgets were developed from just _ 4 downstream of the Caballo Dam to upstream of the American Dam. Since it is 5 desired to investigate the impacts of the alternatives on water quality, the 6 balances are also used to perform mass budgets of total dissolved solids 7 (IDS).

8 The study area is divided into two reaches-the Rincon Valley and the Mesilla 9 Valley. The Rincon Valley reach (or Reach 1) extends from below Caballo -10 Dam to upstream of the Leasburg Dam, and the Mesilla Valley reach (Reach 11 2) includes the Leasburg Dam and runs to upstream of the American Dam. 12 For each of the reaches, spreadsheets are used to perform the water balances.

13 Three water supply scenarios representing historical hydrologic conditions 14 were developed for each of the balances. This was accomplished by arranging -15 releases from Caballo Reservoir for the years 1938 through 1993 in increasing 16 order. The years with the lowest releases from Caballo Reservoir were 17 classified as "Dry" years. The years with the highest releases were termed -18 ''Normal'' years, and the years between the "Dry" and ''Normal'' years were 19 labeled the "Average" years. Each of the periods, "Dry," "Average," and 20 ''Normal'' contained one-third of the years from 1938 to 1993. Three _21 representative years were then selected from within each range as follows: 22 1951, 1967 and 1971 as "Dry" years; 1970, 1980, and 1984 as "Average" 23 years; and 1988, 1989, and 1993 as "Normal" years. Using three years for _24 each water supply scenario reduces the effect of any data anomalies one year 25 might contain and produces a more representative estimate of hydrologic 26 conditions.

27 The water supply scenarios reflect only different hydrologic conditions. In 28 order to eliminate time-varying characteristics, such as population and demand 29 growth in the comparison between alternatives, representative values for these -30 time-variant parameters were used for each year. For example, to eliminate the 31 effect of an increasing population over time, a constant M&I demand is used 32 for all years.

33 Four cases were simulated for each of the three hydrologic scenarios: 34 Baseline, Alternative I, Alternative 2, and Alternative 3. The Baseline case -35 simulated "Dry," "Average," and ''Normal'' years under existing operating 36 conditions, while the simulations for each of the alternatives represented 37 conditions with the corresponding alternatives in place.

96 I The water budget analysis provides a means of comparing system wide 2 impacts of the various alternatives. In order to construct the water and mass 3 balances, many assumptions were made on the hydrologic characteristics and 4 operations within the study area. While the results of this analysis provide a 5 useful and valid method of comparison for the alternatives, the results should 6 not be extended beyond the scope of their intent. The results should not be 7 used to make design or operating decisions. Since some variables were 8 modified to provide a consistent comparison among the water supply scenarios 9 and the alternatives and, further, only a relatively short period of time was 10 used in the analysis, the results do not represent an historic water and mass 11 balance of the system.

12 Methodology

13 For each reach and each water supply scenario ("type" of year), there are 14 water balances which address the alluvial aquifer, the river, and the land and 15 IDS mass balances for the river.

16 Since each alternative is compared with the Baseline case in order to assess its 17 impacts, it is necessary to assume that historical conditions in the Rincon and -18 Mesilla Valleys do not change with the implementation of the alternatives. 19 Thus, historical irrigation and municipal and industrial demands will continue 20 to be applied and be satisfied through the facilities available in the Baseline -21 case.

22 However, each alternative will be able to satisfY additional demands _23 downstream of American Dam. The water demands estimated in the year 2015 24 are used for each of the alternatives. These demands were supplied by the 25 EPWU and found in the El Paso Water Resources Management Plan Study, _26 Phase 1 Completion Report (Reference 1) Facilities Master Plan (Reference 27 27).

28 The estimated 2015 agricultural water demands downstream of American -29 Dam are assumed to be the demands for the "Average" water supply scenario. 30 To obtain the agricultural demands for the "Dry" scenarios, the "Average" 31 annual demand is multiplied by the ratio of the "Dry" year agricultural water -32 demand and the "Average" year demand in Reach 2. To obtain the agricultural 33 demands for the "Normal" scenarios, the ratio of the ''Normal'' year 34 agricultural water demand and the "Average" year demand is multiplied by the -35 "Average" annual demand. These ratios were determined to be 0.8 and 1.12, 36 respectively. It is assumed that M&I demands would not change for different 37 hydrologic conditions.

97 I Baseline 2 The Baseline case is developed using data from historical records for each 3 water supply scenario. Where complete data are not available, estimates of 4 missing data are made using existing data or information from studies. The 5 Baseline case is compared to each alternative to assess the impacts of 6 implementing the alternatives on river flow, return flows, diversions, water 7 quality, etc. The Baseline case also provides the foundation for each of the 8 alternatives. Changes are made to the Baseline case in order to reflect the 9 operation of the alternatives.

10 Once values have been input and the calculations performed for each of the II balances and for each of the study years, the results from the three years 12 forming each water supply scenario are averaged. Thus, balances -13 representing average "Dry", "Average", and "Normal" periods are produced. 14 The mass balances and water budgets are balanced based on these average 15 balances.

16 In order to balance the Baseline case, certain assumptions were made as 17 follows:

18 o There is no change in water storage in the land spreadsheet. Thus, total 19 inflow to the land equals total outflow from the land in each reach.

20 o There is no change in water storage in the river. Total inflow into the 21 river in a reach equals the total outflow from the river in the same reach. 22 The net river seepage is adjusted so that this assumption is satisfied. 23 Thus, a positive net river seepage indicates a river loss to the alluvial 24 aquifer, while a negative river seepage corresponds with a river gain from 25 the alluvial aquifer. 26 o There is no change in the IDS mass of the Rio Grande. The total mass 27 inflow into the river in a reach equals the total mass outflow from the river -28 in the same reach. In the alternatives, the outflow of mass from each reach 29 is unknown, and the balances are adjusted to solve for it. _30 o There is no change in water storage in the alluvial aquifer in the Mesilla 31 Valley (Reach 2). In this case, the net leakage to the Mesilla Basin was 32 adjusted to solve the balance. Due to the alluvial aquifer's hydraulic _33 connection to the Mesilla Basin, the ground water level of the alluvial 34 aquifer is assumed not to change in the Mesilla Valley. Any changes in 35 flow to or from the alluvial aquifer is reflected in a similar change in the _36 flow to or from the Mesilla Basin.

98 1 L] A change in storage in the alluvial aquifer occurs in Reach 1 since it is not 2 connected to another aquifer.

3 Once the Baseline case is balanced, the ''Dry,'' "Average," and ''Nonnal'' year 4 spreadsheets are used to develop the balances for the proposed alternatives. 5 Many of the quantities and assumptions made in balancing the Baseline case 6 are also used in balancing the alternatives. The following discussions will 7 focus primarily on differences from approaches and assumptions used in 8 balancing the Baseline case.

_ 9 Alternative I

10 This alternative consists of a new open conveyance channel that would 11 transport water for the EPCWID#I, Mexico, and the City ofEI Paso. The 12 conveyance canal will extend from the Percha Diversion Dam to its 13 downstream terminus at the American Dam in El Paso. -14 The conveyance structure for this alternative is a concrete-lined, trapezoidal 15 canal designed for gravity flow. It will be isolated from the Rio Grande flows, 16 return flows from agricultural lands, municipal and industrial wastewater -17 discharges, and storm water runoff inflows within each reach. 18 Within the Rincon Valley, there are assumed to be no changes in municipal _19 and industrial use or agricultural use. A new water treatment plant would be 20 constructed at Anthony in the Mesilla Valley reach and would take water from 21 the new conveyance channel for M&I use by EI Paso Water Utilities, Mexico, _22 and southern New Mexico. The conveyance channel would also carry water 23 to the American Canal for use by El Paso Water Utility (EPWU) and for 24 irrigation downstream of the American Dam.

25 The amount of water to be diverted into the new conveyance channel is 26 determined by the estimated 2015 demands for agricultural and M&I uses 27 downstream of American Dam and M&I uses in Reach 2. At times, the -28 historical flows available in the river are not adequate to meet projected 29 demands. If there is a lack of available water to meet the full demand, the 30 water released into the new conveyance canal is adjusted in several ways.

31 1. Caballo Dam is "operated" so more water is released in one month and 32 less in another, but the total annual release is the same as the historical or -33 Baseline case for each type of year. This allows the available water to be 34 used efficiently by retaining water in months when there is a sufficient 35 supply to meet demands and releasing a similar quantity of water in -36 months when the historical supply will not meet demand.

99 I 2. Ifthe reservoir operation can not provide the users with a full supply of 2 water, the amount of water delivered to the entities is reduced. Ground 3 water pumping would be used to provide water necessary to meet the 4 unfilled demand.

5 3. In some months the available water supply rnay be so little that all water 6 could be used to meet demands, leaving no water in the river. To prevent 7 the river from "drying up," the canal releases were adjusted so that a 8 minimum of 1000 a£lmonth offlow would remain in the river.

9 In all cases the available water is used to its maximum efficiency, but due to -10 its scarcity, it rnay not be able to provide a full supply to all users in all II months and years. When the Rio Grande is unable to fulfill the complete water 12 demand, the quantity of water delivered to the various entities using the water -13 is reduced. This deficit in surface water supply was distributed above and 14 below American Dam using 58 and 42 percent, respectively. The deficit in 15 supply above American Dam was distributed among surface water demands in -16 proportion to the amount of water delivered to these demands in the baseline.

17 Alternative 2

18 This alternative involves the development of an open conveyance channel to 19 convey flows by gravity from the Percba Diversion Dam to the historic -20 agricultural turnouts located within the Rio Grande Project, to M&I sources in 21 Reach 2, and to agriCUltural and M&I users downstream of American Dam. 22 Since existing canals will be concrete lined, and seepage losses should be -23 reduced. Inflows to the canal from agricultural return flows, storm runoff 24 inflows, and municipal wastewater discharges will be prevented

-25 Alternative 2 is assumed to operate in a manner similar to Alternative I.

26 Alternative 2a, which includes blending of return flows and runoff with the _27 canal supply was not directly addressed in the water budget.

28 Alternative 3 29 A new pipeline would be constructed under this alternative to convey water 30 from the outlet works at Caballo Dam to the proposed Anthony water -31 treatment plant and to EI Paso. The pipeline would cany water only for M&I 32 use in Reach 2 and downstream of American Dam. As in Alternative 1, there 33 would be no changes in M&I or agricultural uses in Reach I and Reach 2.

34 The same procedures and assumptions were used for this alternative as for 35 Alternative I.

100 1 Results

2 The results of the water budget analysis are presented in this section. The 3 Baseline case provides a means to estimate the effect each potential project 4 may have on the hydrologic system in the Mesilla and Rincon Valleys. In the 5 description of the Baseline results, the trends in each balance from one "type" 6 of year to the next will be discussed. In the description of the alternatives, the 7 results of the "Composite" year for each alternative will be compared to the 8 Baseline and to each other. 9 The "Composite" year is the average of the "Dry," "Average," and "Normal" -10 years. Each parameter for each of the three water supply scenarios is averaged 11 to yield a composite parameter value and create a "Composite" year balance.

12 Baseline

13 As the availability of water from the Rio Grande increases, river flow to -14 agriculture increases, agricultural ground water pumping decreases, drain IS flow increases slightly, canal and lateral seepage increases, and canal waste 16 return increases. Tributary inflow to the river, and M&I return flow and -17 consumptive use are assumed to remain constant for all year types. These 18 relationships remain consistent for all the reaches and alternatives. -19 Deep percolation of water from the soil zone to the alluvial aquifer increases 20 from the "Dry" to the "Average" year because more water is applied to the 21 land in an "Average" year, but from an "Average" to a "Normal" year deep -22 percolation decreases. It appears that more water is actually applied to the 23 crops in an "Average" year because more ground water is used and is 24 delivered more efficiently than water delivery via canals. Although there is -25 more water available in a ''Normal'' year, more of the transported water is lost 26 to seepage and evaporation. 27 There is a large increase in seepage from the river from the "Dry" year to the - 28 "Average" year, but the "Average" and ''Normal'' years' river seepage values 29 are about the same. This might be explained by an increase in the wetted 30 perimeter of the Rio Grande. A larger wetted perimeter means that there is -31 more area for water to flow through to the alluvial aquifer. The wetted 32 perimeter probably increases from the "Dry" to the "Average" year due to 33 increased flow in the river, but due to the large width and flatness of the - 34 channel, the wetted perimeter increases only slightly from the "Average" to the 35 ''Normal'' year. In Reach I water flows from the alluvial aquifer into the river 36 (a negative river seepage), and in Reach 2 the river loses flow to the aquifer (a -37 positive river seepage).

101 1 In Reach 1 there is a slight decrease in the amount of water stored in the 2 alluvial aquifer in the "Dry" year because more water is withdrawn due to 3 ground water pumping than flows into the aquifer. In the "Average" year, 4 there is essentially no change in storage - inflows equal outflows, and in the 5 ''Normal'' year when there is little ground water pumping and more seepage 6 from the river and canals, the ground water storage increases in the alluvial 7 aquifer. In Reach 2 it is assumed that since the alluvial aquifer is in hydraulic 8 connection with the Mesilla Basin, any increase of flow into the alluvial 9 aquifer would increase the flow into the Mesilla Basin and the storage in the 10 alluvial aquifer would remain relatively constant.

11 In Reach 1 the total mass of IDS in the river inflow and outflow of the 12 "Average" and "Dry" years is about the same. The "Average" year has 13 greater flow, but the concentration of IDS is less. The ''Normal'' year -14 contains a greater mass of IDS because the flow is greater and the 15 concentration of the IDS in the water is about the same. In Reach 2 the IDS 16 concentration in the river increases due to the inflow from drains and canal - 17 waste returns, and the mass of IDS increases as the water flow increases.

18 Figures 37 and 38 show the composite results of the water and mass balances -19 for the Baseline case. The spreadsheets for each balance for each water supply 20 scenario can be found in Appendix D.

21 Alternative 1

22 Due to the proposed diversion at Percha Dam, Alternative 1 reduces river -23 flows at Leasburg Dam from 612,200 af/year (Baseline) to 286,000 af/yr 24 (Alternative I), and the flow at American Dam decreases from 358,900 af/yr 25 (Baseline) to 58,000 af/year (Alternative 1).

26 There is a higher concentration ofTDS flowing through American Dam, but 27 due to the low flows, the total mass of IDS is much less. The TDS -28 concentration (600 mg/l) at Leasburg Dam is about the same for the Baseline 29 and Alternative 1, but the IDS concentration is higher at American Dam for 30 both cases. Alternative 1's IDS concentration increases to about 2000 mg/1 -31 whereas in the Baseline IDS concentrations increase to about 800 mgll.

32 Alternative 1 supplies a full allocation of water in the ''Normal'' year, but not 33 in the "Dry" and "Average" years. An additional 16,000 af/yr is needed in the 34 "Average" year, and 158,600 af is required in the "Dry" year. It is assumed 35 that additional water would be acquired from ground water pumping.

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All quontlties ore in 1000-tons unless otherwise noted, Figure 38 I In Reach 2 ground water pumping for M&I decreases to 6,500 af/yr 2 (Alternative 1) from 46,200 af/yr (Baseline). Corresponding to this decrease in 3 M&I ground water pumping, canal flow to M&I increases from 0 af/yr to 4 39,700 af/yr.

5 Figures 39 and 40 show the composite results of the water and mass balances 6 for Alternative 1. The spreadsheets for each balance for each water supply 7 scenario can be found in Appendix D.

8 Alternative 2

9 On the average, less water flows past the headgate to agriculture in 10 Alternative 2 compared to the Baseline. Alternative 2 lines the main canal 11 which reduces canal seepage. Since there are less losses, less water needs to be -12 sent to agriculture. Essentially Alternative 2 "saves" water. On the average, 13 Alternative 2 reduces canal losses by about 13,500 afiyr in Reach I, and in 14 Reach 2 it reduces losses by about 20,000 af/yr.

15 In Reach I, due to the reduction in canal seepage and an increase in ground 16 water pumping, there is a net loss in storage in the alluvial aquifer. The -17 storage decreases by about 35,600 af/yr for Alternative 2 compared with an 18 average increase in the Baseline case of2,100 af/yr. In Reach 2, the leakage 19 from the alluvial aquifer to the Mesilla Basin decreases by about 55,700 af/yr _20 due to Alternative 2.

21 Since much of the Rio Grande flow is diverted to the new canal at Percha 22 Dam, the composite annual flow at Leasburg is 11,900 af/yr for Alternative 2 23 compared to 612,200 af/yr in the Baseline case. Due to the influx of canal 24 waste return and drain flow in Reach 2, the Rio Grande flow increases to 25 135,700 afiyr at American Dam for Alternative 2. Due to the consumption of 26 river water by agriculture in Reach 2, the Rio Grande flow decreases to 27 358,900 af/yr in the Baseline case.

-28 In the ''Normal,'' "Average," and "Dry" years, it cannot supply enough water 29 to meet demand, and there is a 48,200, 135,700, and 222,300 af/yr deficit, 30 respectively. The composite deficit in providing a full supply of water is -31 135,400 af/yr. It is assumed that additional water would be acquired from 32 ground water pumping.

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Al I quontities ore in 1000-tons un less otherwise noted. Figure 40 I Since the rate of flow in the Rio Grande is much less at Leasburg Dam and - 2 American Dam in Alternative 2, the amount of IDS mass transported by the 3 river is less, but the concentration of IDS is higher in Alternative 2. The IDS 4 concentration at Leasburg Dam increases from about 600 mg!l (Baseline) to - 5 approximately 2000 mgII (Alternative 2), and the IDS concentration at 6 American Dam rises from 800 mg!l (Baseline) to 1000 mg/l (Alternative 2).

7 Figures 41 and 42 show the composite results of the water and mass balances 8 for Alternative 2. The spreadsheet for each balance for each water supply 9 scenario can be found in Appendix D.

10 Alternative 3

-II Since the pipeline provides water to M&I users in Reach 2, M&I ground 12 water pumping is reduced from 46,200 a17yr (Baseline) to 4,500 a17yr 13 (Alternative 3). It is assumed that M&I ground water pumping withdraws -14 water from the Mesilla Basin and not the alluvial aquifer.

15 Alternative 3 reduces river flow at Leasburg Dam from an average of 612,200 16 af/yr (Baseline) to 351,800 af/yr (Alternative 3), and at American Dam the 17 flow decreases from 358,900 af/yr (Baseline) to 108,600 af/yr (Alternative 3)

By rearranging releases from Caballo Dam, Alternative 3 is able to provide a full supply of water to its intended users in the "Average" and "Normal" years. In the "Dry" year there is a 70,000 af/yr deficit in the full supply of water delivered by the project. Ground water pumping is assumed to provide the water needed to eliminate this deficit.

23 Although the TDS concentration of the Rio Grande is higher in Alternative 3, -24 less IDS mass is moved through the river because there is less flow in the 25 river. The Baseline case and Alternative 3 have an estimated TDS 26 concentration at Leasburg Dam of 600 mgll, and the TDS concentration for -27 both scenarios is about 800 mgll to 1000 mg/l at American Dam.

28 Figures 43 and 44 show the composite results of the water and mass balances 29 for Alternative 3. The spreadsheet for each balance for each water supply 30 scenario can be found in Appendix D.

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~ Co) Total Dissolved Solids (TDS) Mass Budget Alterna tive 3

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. ~l< ..------~\\\~ I·. ~:-'-/T":" 500.' • •~_. ____' __\t-.' .... ~~A~' / RIVER..INrL""~~~::.~_ /-.--. ___._ ...... _ ...-, __.. __ ,c='.~/f:y,,4*~' ..~.~~ .. ~ ~.>.';. ~~4" ,'~, '. ~<> .~ ,,~v .~-<:>:--~,,-.~- )71'/. ~/r..v-i"/'-' 9-'\l<.~:: ... < > -,'-'.' --]~ ... .~-'~ " ./ F' . 277.8 =z::~- .. "':-:-== ' ~-:>' RIVER [JJTrL~ .~ ~~ ~ ~~e; '"-, . "''''~ 'V v I I j v

EstiMQted River InFlow TDS ConcentrQtion (Mg/l) 600 EstiMQted River InFlow TDS ConcentrQtion (Mg/l) 600 EstiMQted River OutFlow TDS ConcentrQtion (Mg/l) 600 EstiMQted River OutFlow TDS ConcentrQtion (Mg/l) 1000

All qUQntities Qre in 1000-tons unless otherwise noted, Figure 44 Additional Considerations

1 Canal and Drain Storage

2 Regulating reservoirs could be designed and included in the raw water 3 conveyance systems for three primary purposes. First, the reservoirs could be 4 used to stabilize the flow in the canal downstream of the thereby reducing 5 spills. Specially designed gates would be installed on the reservoir outlet to 6 maintain a nearly constant outflow. The reguIating reservoir would need to be 7 large enough to store water from short term peak flow periods to provide 8 constant outflow during short term low flow periods in the canal. Secondly, 9 the regulating reservoirs could be used to deliver water to users on demand _10 and to compensate for the time of travel of water from CabalIo Dam to the 11 turnout location. This regulation improves the efficiency of delivery and 12 provides water conservation by catching and storing water that would 13 normally be lost to canal spillage (operation waste). Boyle estimated that the 14 average canal spillage was 16 percent in 1990 for the EPWCID#I and 9 15 percent for EBID (Reference 1). They also estimated that the operation 16 spillage could be reduced to 5 percent with regulating reservoirs. The 17 regulating reservoirs were then expected to save up to 27,000 af of water 18 (average) annually from the EPWCID#I and 17,700 afannually from EBID. 19 Third, the reservoirs could be used for recreation and environmental 20 enhancement of the surrounding areas.

21 Raw water storage wilI also be needed near each of the possible water -22 treatment plants near Dona Ana, New Mexico and Anthony, Texas. The raw 23 water storage reservoirs for these plants were located and sized to provide a 24 stable flow of water to the water treatment plants and to regulate the flow in -25 the conveyance system downstream of the treatment plant diversion. 26 Additional regulating reservoirs were located solely for the purpose of flow 27 regulation along the conveyance systems. These additional reservoirs would -28 remove some hydraulic transients from the system, stabilize flows in the 29 canals, provide short term storage ofpeak flows that are in excess of the 30 demand, develop recreational areas, and provide environmental enhancements -31 and mitigation. The efforts in this report focused on defining where the 32 reservoirs could be placed (potentially), how much water they could store for 33 flow regulation, and how much raw water storage would be needed for the -34 water treatment plants.

35 Four regulating storage reservoirs were identified in New Mexico to help _36 improve the operating efficiencies of the conveyance alternatives, conserve 37 water, and provide raw water storage for the water treatment plants. The 38 potential locations of the regulating reservoirs are shown in Figure 45. Table _39 20 includes an estimate of the regulating capacity, the total storage, the 40 surface area, and a listing of which conveyance alternatives are applicable for

113 I each reservoir. For cost estimate purposes, the channel expansion reservoirs 2 were assumed to follow the channel. Other reservoir shapes may be 3 economically, technically, and environmentally more feasible and should be 4 addressed in further studies. 5 Table 20 6 Regulating Reservoirs Description Reservoir Surface Average Storage Storage 24 Hour Alternative Label Area Depth Total Regulating Outflow Number Name Acres (feeO !l!fl 00 (cfs) AI!i!Iicable AMI 40 10.1 400 100 50 1,2,2a CI 50 10.7 500 125 63 2,2a MI 40 10 400 200 100 2,2a LCI 50 12.7 600 125 63 2,2a Totals 180 1900 550 276

7

8 Reservoir "AMI" (regulating water delivery to American Dam) could be built 9 by widening the main conveyance channel to 200 feet, and raising the water 10 depth to a maximum depth of 12.6 feet, with the canal design depth being 7.6 II feet. The dikes along this reservoir would need to be 4 feet above the 12 maximum water surface (above the canal dikes) to provide the necessary 13 freeboard for a distance of nearly 7,700 feet upstream of the regulating 14 structure. The reservoir could be lined with an impermeable geotechnical IS lining to eliminate seepage.

16 Reservoir "C I" (regulating water delivery to the Anthony Treatment Plant -17 near Canutillo) could be constructed by widening the main conveyance 18 channel to 250 feet, and increasing the water depth to a maximum depth of 19 13.2 feet, with the canal design depth being 8.2 feet. The dikes along this -20 reservoir would need to be 4 feet above the maximum water surface (above 21 the canal dikes) to provide the necessary freeboard for a distance of nearly 22 7,700 feet upstream of the regulating structure. This reservoir would -23 stabilize flows and would be used to provide storage of raw water for the 24 water treatment plant at Anthony. Its design would provide for by-passing 25 most of the flow through the main canal, along with most of the sediments and -26 debris, and would divert the raw water for the water treatment plant through a 27 side diversion. The reservoir could be lined with an impermeable geotechnical 28 lining to eliminate seepage.

114 ChamberinoO Dona Ana County o 3 MIIN

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Legend: River --Canals Poli tical Boundaries Cit Sta\e _ Regulating Reservoirs --Roads

BOYLE ENGINEERING CORPORATION ENGINEERING-SCIENCE, INC,

FIGURE 45 Meadow REGULATING STORAGE New RESERVOIRS Mexico Mexico

[):\124044\REGTN«S.DQN R0108.20.M

--~~------~ 1 Reservoir "Mi" (regulating water delivery to the West Side ofEBID) could be 2 constructed by diking the inlet and east dike of the west side canal to an 3 elevation of nearly 3870 feet, and diking the outlet of the reservoir just south 4 of the rodeo grounds and just below the West Side Canal Inlet. The average 5 depth of the water in this reservoir could be expected to be roughly 12 feet. 6 The dikes along this reservoir would need to be 4 feet above the maximum 7 water surface elevation in the area shown on Figure 3.x. The reservoir could 8 be lined with an impenneable geotechnical lining to eliminate seepage.

9 Reservoir "LC 1" (regulating water delivery to the Las Cruces Water 10 Treatment Plant) could be built by widening the main conveyance channel to -11 250 feet, and increasing the water depth to a maximum depth of 15.2 feet, 12 with the canal design depth being 10.2 feet. The dikes along this reservoir 13 would need to be 4 feet above the maximum water surface to provide the -14 necessary freeboard for a distance of nearly 7,700 feet upstream of the outlet 15 structure. TItis reservoir would stabilize flows in the canal and would be used 16 to provide storage of raw water for the water treatment plant at Las Cruces. -17 Its design would by-pass the majority of flow through the main canal, along 18 with most of the sediments and debris, and divert the raw water for the water 19 treatment plant through a side diversion. The reservoir could be lined with an -20 impenneable geotechnical lining to eliminate seepage.

21 Regulation storage downstream from these locations can probably be handled 22 by the regulating reservoir planned for construction along with the American 23 Canal Extension.

24 Several other regulating reservoirs could be recommended along the main -25 delivery canals for regulation purposes within the individual irrigation 26 districts. However, the location of these regulating reservoirs, their costs, and 27 feasibility will not be addressed in this report. These additional reservoirs -28 would improve the operating efficiency of the existing canals and conserve 29 water to supplement deliveries.

-30 Other regulating storage reservoirs could be constructed along some of the 31 major drains in the Mesilla, Rincon, and El Paso Valleys. These drain 32 regulating reservoirs could be used to conserve water, manage water quality, -33 develop recreational parks, and enhance environmental mitigation. By using 34 regulating reservoirs to capture drain flow and surface runoff, the drain water 35 can be used to recharge the alluvial aquifer, irrigate (when water quality will _36 allow) agricultural crops, supplement (when blended) diversions, and/or 37 enhance environmental mitigation. At present, the State of New Mexico may 38 not recognize environmental enhancements as a beneficial use, but the ~9 mitigative potential may be used to meet National Environmental Protection 40 Act compliance requirements. Environmental enhancements through the

116 1 development of recreational parks, wetlands, riparian habitat, bridal trails, 2 bike and hiking paths, fisheries, and other potential improvements would 3 benefit the entire Rio Grande Project. These improvements would assist in 4 improving the standard ofliving in the area, as well as increase the economic 5 value of the surrounding areas as residential and municipal development 6 continues.

7 Another significant beneficial use of regulated drain flows is to manage water 8 quality in the Rio Grande River. Drain flow salinity tends to peak in the 9 winter months and reach a minimum during periods of high irrigation in the 10 summer. The winter peaks reflect the impacts of the alluvial aquifer flows 11 through areas of highly saline soils to the drains. By installing regulating 12 reservoirs, the peak salinity levels could be significantly lowered by blending 13 the higher quality summer flows from small storage reservoirs. The quality of 14 these flows would require periodic monitoring and review to maintain the salt 15 balance, and to optimize the operations of these reservoirs.

-16 It would be beneficial to identify remotely the soils that contribute the highest 17 salinity, then zone these areas for industrial development. This would allow a 18 reasonable economic return to the present land owners, help protect high -19 quality agricultural lands from municipal development, and provide the 20 irrigation districts the option to reassign the water to other project lands for 21 industrial purposes. By isolating highly saline areas, and potentially installing -22 interceptor drains to reduce ground water inflow through the saline soils, the 23 drain water quality to the river could be significantly improved. Other 24 potential management improvements could include isolating the highly saline -25 drains (TDS> 1000 mg/l) and using this water to sprinkle riparian areas while 26 diverting or piping higher quality drain water to the canals or the river for 27 other uses.

28 The placement of these regulating reservoirs would require careful 29 consideration of the drainage patterns, the quality of the drainage inflows to 30 the reservoirs, the quality of the outflow from the reservoirs, and the overall 31 impacts on the entire hydrologic system. The future development of these 32 ideas will require careful consideration to prevent salting out of agricultural 33 lands and to maintain the purpose of the drains. The drains must continue to 34 carry away the leached salts and prevent the soil from souring or becoming 35 anaerobic.

36 Return Flow Treatment

37 Opportunities for blending of return flows with canal water and for storing -38 return flows to optimize their use have been discussed in a previous section of 39 the report. These return flows would normally be higher in IDS than the main

117 I conveyance supply, as the water budget data indicate. For some uses, such as 2 aquatic and riparian wildlife habitat, industrial cooling water, etc., this may 3 not be a severe problem. For use as an agricultural water source, the return 4 flows could be blended or used as is, depending on the location and crop. As 5 long as irrigated agriculture remains the predominant RGP water use, 6 especially when considering return flows in areas below Leasburg and in dry 7 years, drain flow salinity may be too high for some M&I uses. The return 8 flows may also contain traces of pesticides, nitrogen compounds, higher levels 9 of total organic carbon (TOC) than the canal water, tastes and odors from 10 algae, turbidity or color and many other possible contaminants. For many _11 uses, especially potable water, treatment would be necessary.

12 The type of treatment required would depend on the time of year and location, 13 but is likely to be more expensive than the processes already discussed for 14 treatment of canal water. Additional unit processes such as adsorption of 15 organics on activated carbon and more storage for raw water pre­ 16 sedimentation may be required. In order to meet SDWA requirements for -17 municipal water supply, desalination would probably be necessary. Both 18 reverse osmosis (RO) and electrodialysis reversal (EDR) could be used. The 19 most practical and economical choice would depend on the water quality at the -20 time and location. A combination of advanced conventional water treatment, 21 followed by RO membrane treatment, may be the most feasible scheme for 22 potable water production. As with any desalination planned in the vicinity, -23 handling of the reject brine waste from the membrane process, as well as the 24 conventional chemical treatment waste sludge, must be considered.

-25 It is important to realize that the irrigation waste and drain flows will change 26 in quality and decline in volume along with reductions in the quantity ofRGP 27 water used in agriculture. However, as M&I water use increases the volume of -28 treated wastewater flowing into the river will also increase. 1bis treated 29 wastewater may be reused in place, but will eventually be released to the Rio 30 Grande and become agricultural return flow or ground water. Extensive reuse _31 of wastewater emuent for irrigation should maintain some return flows in the 32 system.

33 It is unlikely that desalination of return flows will be a large scale use in the 34 near future. It is quite possible, however, that treatment can be used to 35 produce potable water and fill other high quality water supply needs in local 36 areas. 1bis might prove practical under certain conditions such as:

37 Cl remoteness from a regional water treatment plant

-38 Cl small demands at, for example, a state park at an area of enhanced 39 wildlife habitat

118 1 Cl complete allocation of the canaI water supply

2 Cl specialized use for boiler feed or other high purity water needs at an 3 industrial facility which might use untreated return flows for its other 4 nonpotable requirements

5 The Commission should keep an open mind about specific uses for treated 6 return flow, although it does not appear to be a practical large scale regional 7 water source.

8 In order to evaluate the practicality of treatment at a particular location, the 9 value of untreated return flow at that location must be added to the canaI 10 supply costs and compared to the return flow treatment cost before a valid 11 decision on the best water source choice can be made.

12 As demonstrated by the results of the water budget, the IDS concentration at 13 American Dam will average approximately 1000 mgll for Alternatives 2 and _14 3. For Alternative I the IDS at American Dam is 2000 mgll due to the lower 15 availability of dilution flows. IDS in the Montoya and East Side Drains 16 would, of course, be higher. If drain sources in this area are to be used as a 17 potable supply, desalination would obviously be necessary. If the Rio Grande 18 is conveyed to the drains through the water blending system, IDS may drop 19 dramatically for short periods during the thunder storm season, making for 20 variable IDS in the treatment feed water.

21 Aquifer Storage and Recovery

22 Aquifer Storage and Recovery is the storage of surface water in a ground 23 water aquifer for later retrieval. Aquifer storage offers significant possibilities 24 for augmenting supplies and reducing surface water treatment plant capacities. 25 Treated surface water is already being used for part of the municipal supply in 26 EI Paso during the irrigation season, because of the ongoing depletion of 27 ground water in the Hueco Basin. However, ground water has been, and -28 continues to be the primary source of M&I water for EI Paso and other 29 communities in the Commission planning region. With a ground water 30 production system in place, aquifer storage of surface water may greatly -31 reduce necessary peak water treatment plant capacities. Aquifer storage also 32 provides a means to insure long term stability of water quantities in the 33 aquifers. If a net surplus of water is used, which would not be difficult once a -34 recharge program is implemented, the depleted aquifer could eventually be 35 restored to near the original capacity.

-36 Conveyance to provide year-round water offers the opportunity to consume 37 less groundwater for M&I uses by providing surface water at average

119 1 consumption rates, less other sources of supply or recharge. This will result in 2 availability of excess surface water in the winter and would allow storing of 3 surface water in the aquifers. Water can then be withdrawn to meet peak 4 summer demands without resulting in net depletion of the ground water 5 supply.

6 The two ground water aquifers in the area, the Hueco Basin and the Mesilla 7 Basin, will be studied for their suitability for aquifer storage and recovery in 8 an upcoming, follow-on study to the phase IIJIIl work. The Hueco Basin 9 currently has suffered the largest depletion with resulting intrusion of brackish 10 water at the margins and large draw downs requiring deeper pumping --11 equipment submergence. As the El Paso and Juarez areas continue to grow, 12 production from the Hueco Basin will become impractical unless a rapid 13 switch to surface water avoids further overpumping. Although the overall -14 capacity of the Mesilla Basin is greater, its capacity is also finite, especially 15 when considering the capacity available to El Paso and Juarez without 16 importing ground water from New Mexico. By the end of the study period in -17 2035, water banking in both the Hueco Basin and the Mesilla Basin, which 18 will probably prove to be feasible, would greatly reduce required surface 19 water treatment capacity and help preserve both of the aquifers. 20 M&I water usage in southern New Mexico and EI Paso County area varies 21 during the year with low use in the winter increasing to the highest usage _22 during late June or early July. Winter use can be as low as 40 percent of the 23 average increasing to as high as two times the average during the summer. 24 Although summer peak use spans only two or three months, supply facilities -25 need to be large enough to meet this peak demand. Consequently, water 26 treatment plants have unused capacity during the winter months, when demand 27 is low, if they are designed to meet the high summer peak.

28 Currently, water treatment plants operate only during the irrigation season, 29 when surface water of acceptable quality is available. With the introduction of 30 conveyance facilities, surface water of higher quality will be available year 31 round. During winter months when water usage is less than the yearly 32 average, extra treatment capacity and water supply would be available. 33 Aquifer storage takes advantage of this situation to provide optimum year -34 round surface water use. During the winter months, when water use is low, the 35 excess of surface water production over demand could be pumped from the 36 treatment plants, through the distribution system and into the underground -37 aquifer. During the summer high water usage months, the stored water would 38 be pumped by the existing ground water production system to meet the peak in 39 usage, allowing the surface water treatment plants to treat at a more or less -to constant rate year round. Some excess surface water capacity above net

120 I average demand would still be necessary to allow down time for service of 2 process and pumping equipment in the treatment plants.

3 Two methods can be used to introduce water into an aquifer. One method is to 4 use injection wells, either specially constructed injection wells or existing 5 production wells operated in reverse. Another method is by spreading water 6 into an infiltration basin at the surface. Use of injection wells requires that the 7 surface water be treated to drinking water standards prior to introduction into 8 the aquifer. It also requires attention to corrosion control and the chemical 9 compatibility of the injected water with that already present in the aquifer. The 10 water is injected at points where it can be retrieved by ground water wells _. 11 during periods of peak use. Because of possible contamination by peripheral 12 or overlying brackish water, the potential for injected ground water to migrate 13 laterally to a location where it may be unavailable for production and the -14 possibility of other users of ground water producing water injected by 15 Commission entity, the location at which the water is injected, both above and 16 below ground, is very important for the practicality of future retrieval. The -17 best locations may be in areas where the water quality remains suitable but 18 where there is a cone of depression due to over pumping. The cone of 19 depression can be partially refilled and will hold the water near the point of -20 injection. The use of injection wells allows control of the water quality and 21 relatively precise location of recharge. However, surface water treatment and 22 possible additional corrosion control treatment may be necessary.

23 The second method, spreading in an infiltration basin, may allow use of 24 untreated or partially treated surface water. Depending on the quality of the _25 raw water, pre-sedimentation may still be necessary. The spreading is 26 conducted in an area which allows transport of the water by percolation 27 through the ground down to the aquifer. Selected spreading locations are used _.28 and dikes may be necessary to hold the water over the infiltration bed. The soil 29 acts as a filter to remove sediment and organic contaminants before they reach 30 the aquifer.

31 Surface spreading provides an economical way to recharge an aquifer; 32 however, some potential problems can result. The feasibility of surface 33 spreading is highly dependent on the permeability and chemical characteristics 34 of the underlying sediments. Build up oftota! dissolved solids and/or specific 35 cations or anions of concern can occur. An area offairly high permeability 36 (large uncemented sediment particles above and within the zone of saturation) -37 must be used to allow practical rates of infiltration. Subsurface layers of 38 caliche or clay may retard infiltration or produce perching at depths above the 39 ground water table. Some lateral movement may also occur prior to reaching -40 the primary production aquifer.

121 1 In general, coarse sediments and shallow depths to groundwater make surface 2 spreading more practical. Surface spreading requires a good knowledge of the 3 geology above the ground water table and would probably require pilot studies 4 prior to investments in a large scale operation. During the time the water is at 5 the surface it is subject to evaporation which can consume a significant 6 portion of the applied volume and concentrate the total dissolved solids. The 7 evaporation problem increases if infiltration rates are slow.

8 Either method of aquifer storage would hold water for retrieval at a later time 9 and provide a means of recharging the depleting aquifers. Aquifer storage 10 would also provide long term storage for retrieval during drought periods, as 11 discussed later in this report.

12 To determine the feasibility of underground storage and the most effective -. 13 recharge method, further study is necessary. Additional study should identify 14 potential sites based on surface and subsurface attributes, evaluate the 15 feasibility of the two recharge methods at that location and predict the water -16 quality effects that might result. Determination of the overall feasibility of 17 aquifer storage should be based on cost comparisons, retrievable storage 18 capacity and sustainable recharge rates. Information from the water budget -19 developed for this report will be used in the upcoming aquifer storage study.

The planned follow-on study will evaluate aquifer storage and recovery at four sites:

o In the Las Cruces area

o West of La Union in Southern Dona Ana County

24 o In the Canutillo Wellfield area north ofEI Paso

25 o In the Northeast Hueco Basin area of EI Paso

26 Both spreading and injection will be considered. The results of this study 27 should provide the Commission with insight into the feasibility of aquifer 28 storage and recovery as part of overall regional conjunctive use. Aquifer 29 storage offers tremendous potential to protect and restore depleted aquifers, -30 while optimizing water use efficiency.

31 Drought Contingency

32 Although surface water originating from the storage facilities on the Rio 33 Grande may be considered a permanent source of supply, in the particular '-34 case of the Rio Grande Project, the actual amount available each year varies 35 according to operating policies based on the amounts in storage in Elephant

122 1 Butte and Caballo Reservoirs, and on climatic occurrences and forecasts. 2 Annual allotments of water available to the Rio Grande Project lands are thus 3 variable, and water supply for M&I uses based on acquisition of water from 4 these lands would be subject to similar variations.

5 The reliability of the Rio Grande Project as a source of water supply has been 6 studied through use of return-frequency analysis on annual net supplies to the 7 EPCWID#I (Reference 1). From this approach, it has been determined that 8 the probability of the annual net supply in any given year being equal to or 9 greater than the long-term average annual net supply is 56 percent. -- 10 During extended periods of drought, Rio Grande Project allotments are II decreased in accordance to the severity of the drought. Historically, 12 allotments have fallen as low as 0.5 afper acre from a normal of3 afper acre. --13 When only reduced amounts of Rio Grande Project water are available, 14 farmers may opt to reduce their farmed acreage to an amount compatible with 15 the water supply; they may pump ground water and thus limit the reduction in -16 their farmed acreage; or, iffeasible, they may forego farming during the 17 drought period. Operators of treated water supply facilities for M&I uses do 18 not have this flexibility to adjust their demand to available supply.

19 For the City of EI Paso, EPWU is committed to supply the normal demand, 20 decreased only by possible emergency conservation measures. One possible _21 arrangement that would help to satisfy the expectations for water supply of 22 both the farmers and EPWU could be for both parties to enter into long-term 23 drought contingency agreements. Such agreements could provide that in years __ 24 when the initial water allotments are below a certain set amount, farmers 25 would commit to lease their water allotment for that year to EPWU for M&I 26 water supply, and in return, EPWU would pay farmers a certain pre-specified _27 fee per acre foot of water ceded to EPWU. In this process, farmers would be 28 guaranteed an income, even if limited, and EPWU would help alleviate a 29 shortage in their water supply operations during drought periods. When _30 Mexico, Las Cruces and Dona Ana County become users of treated surface 31 water, they may wish to make similar arrangements with EPCWID# 1 and 32 EBID farmers to address dry years.

-33 Another solution for dry years is conjunctive use of ground water. Ground 34 water can be pumped to supplement available surface water in dry years, in 35 similar fashion to its planned use to meet peak summertime demands for M&I -36 water. Iflarge amounts of water are available in storage, or in areas where 37 demand is relatively low and natural recharge is able to replenish the periodic 38 withdrawals, this practice can continue more or less indefinitely. In high -39 demand areas like EI Paso and Juarez, aquifer storage and recovery would be 40 a necessary part of using groundwater as a source for drought contingency.

123 1 With a good program of aquifer storage, the aquifers can be used as a drought 2 contingency bank, and perpetually protected from depletion. Use of 3 groundwater as a drought contingency supply mandates that a system of 4 groundwater production wells and collector lines be maintained. It also 5 requires a system and plan for aquifer recharge in those areas where 6 significant draw downs have occurred or will occur from future demands.

7 Environmental Considerations

8 The Legal Advisory Committee of the New Mexico-Texas Water Commission 9 has considered environmental issues. The Legal Advisory Committee and 10 Management Advisory Committee also conducted a presentation to interested 11 government agencies on April 28, 1994. Follow up discussions were held with 12 specific members of state and federal agencies, interested citizens and 13 environmental groups. From these initial discussions and from the previous 14 experience of the Commission members and the legal and engineering 15 consultants, some expectations as to the environmental issues which will result 16 from consideration of a large scale surface water conveyance, and an initial 17 plan for addressing them have been developed.

-18 The first reaction to diversion of all or a major portion of the reservoir 19 releases from the river to a lined canal is likely to be negative. It will be 20 assumed that such a diversion will have negative impact on aquatic life and on -21 the viability and aesthetic appeal of the Rio Grande and associated wildlife 22 and recreational uses. An environmental assessment will be necessary, 23 particularly if any federal funds are to be used on the project, and an -24 environmental impact statement may be required.

25 Prior to any environmental assessment work, the Commission should use the -26 information provided in this Phase IIIIII report to decide on a common set of 27 objectives. One major common objective which is already identified is the need 28 to preserve and restore the Hueco and Mesilla ground water aquifers. In order _29 to establish this and other common objectives, the parties who are to make use 30 of the conveyance must be defined. These parties can then develop a set of 31 common objectives for conveyance and use of the renewable surface water _32 supply. Once a common set of objectives is determined, two or three 33 variations on the appropriate means to satisfy the objectives 34 (conveyance/treatment alternatives) can be identified. The relative feasibility _)5 of these alternatives will then be evaluated from both an environmental and 36 economic viewpoint and compared to the "no action" alternative. A lead 37 federal agency, the agency that will be in charge if an environmental impact _38 statement is necessary, should be identified. Environmental assessment work 39 should start by compiling existing data and proceed to new field studies if 40 necessary.

124 1 The environmental assessment will involve extensive public involvement. It 2 will be the first time many local citizens, environmental groups and other 3 public and private organizations become aware of the project. It is important 4 that they be made aware of the following facts.

5 [] The existing river below Caballo Reservoir is basically an irrigation 6 canal and floodway. The natural riparian vegetation has been cleared 7 and the non irrigation season flow is made up of irrigation and 8 wastewater return flows and occasional storm water runoff. 9 [] Year round delivery of surface water of high quality and adequate -10 quantity will allow major municipalities in the area, including Las 11 Cruces, El Paso, and Juarez, to discontinue overdraft of the Mesilla 12 and Hueco Basins, thus preserving the important regional ground -13 water aquifers.

14 [] Water banking of the year round surface water supply will allow _15 summer peak municipal water demands to be met while preserving 16 and restoring the ground water aquifers.

17 [] Well thought out use of return flows and storm water runoff may 18 actually enhance the aquatic and riparian habitat and recreational 19 value of the Rio Grande Project system to a level above the "no action 20 alternative. "

21 [] Moving from use of depletable ground water to a sustainable surface 22 water supply is necessary to supply even the present population in the -23 area and will allow improvement of environmental conditions and the 24 quality oflife of many of the area's residents.

_25 [] Minimum stream flows can be maintained, marshes and wildlife 26 management areas can be developed with managed use of return 27 flows, and any environmental losses can be more than mitigated by a _28 well thought out project.

29 The Commission should adopt a pro-active and cooperative approach in 30 explaining the project and design it to accommodate the public interest. The -31 project can be used to restore aquifers, enhance the local environment and 32 provide a dependable and permanent water supply. Interested parties must be 33 made to understand that the project is a plus, not a minus, to all of the -34 interests of the region.

125 Summary of Study Results

1 This section summarizes the results detennined from analysis of the 2 alternative objectives. It is included to assist the members of the Commission 3 in selecting an appropriate conveyance system. Issues such as regional socio­ 4 economic impacts, specific environmental impacts, and legal-institutional 5 constraints are not addressed in the study.

6 The evaluation parameters are those dealing with water resource management 7 from an engineering perspective, including:

8 LJ Advantage/disadvantage of alternatives.

9 LJ Unit conveyance and treatment cost determination including estimates 10 of construction cost and operations/maintenance costs.

11 LJ System impacts on the Rincon and Mesilla Valleys as indicated by the 12 water budget analysis.

13 LJ Surface water "losses" comparison.

14 LJ Future effects on the Mesilla and Hueco Basins.

_15 The following Figure 46 illustrates the agency service objective of each of the 16 alternatives for referral during evaluations by the Commission. It should be 17 noted that the consultants (Boyle, E-S) have not included an evaluation or a __ 18 recommendation for a preferred alternative.

19 An initial objective perception regarding environmental issues to be addressed 20 is that the major favorable impact of the project is stabilization of the two (2) 21 major aquifers. Any of these three alternatives can adequately address the 22 aquatic and riparian environmental impacts, particularly if public and 23 professional participation is included in the next phase of project development.

24 Certain advantages and disadvantages are exclusive to a particular Alternative 25 Objective. An understanding of the specific advantages and disadvantages of -26 each alternative will help in evaluating the best alternative to meet the 27 evaluation parameters listed earlier. A compendium of advantages and 28 disadvantages follows.

126 en (l) .-> +-'co C L... 2 «- \f-a en "'C -(l) .-u.. (l) .-o 2: en(l) 1 Alternative Objective No. 1

2 Advantages of Alternative 1:

3 1_ The water quality delivered at EI Paso would be the same as that 4 existing in Caballo Reservoir. The quality would be maintained and 5 protected from contamination and degradation by prohibiting 6 intermediate inflows of drain, return, and storm waters.

7 2. The availability of water would be year-round, and flow requirements 8 would be more controllable to meet demands.

9 3. Water conveyance losses due to seepage and evaporation would be __ 10 significantly reduced. The transportation time would be reduced from 11 three days to less than one day.

-12 Disadvantages of Alternative 1:

13 1. The upstream entities would not have available to them the downstream --14 allocation flow for purposes of using it for "carrier" water.

15 2. The downstream entities would receive their full allocation at a point 16 above significant storm water, drain, waste, and return inflows, which 17 are considered to be Project water.

18 3. Not all of the regional entities would directly benefit from the project. 19 To provide equitable benefits to all regional entities, construction of a 20 companion project would be required.

21 Alternative Objective No.2

-22 Advantages of Alternative 2:

23 1. All water agencies and water users of the region will benefit from -24 system-wide improvements to the water conveyance system.

25 2. Regulatory control of system-wide operations of the Rio Grande Project _26 will be centralized. That is, the physical allocation of flows will be in 27 parallel rather than in series.

28 3. All beneficiary agencies will receive water of similar quality, with the -29 option to blend agricultural diversions with "reuse" water from the Rio 30 Grande.

128 1 4. The project construction cost per unit volume of water delivered is the 2 lowest of the alternatives considered (see Cost subsection below).

3 5. Local agencies can be more responsive to the future shifts of the water 4 needs of the region than can state or federal officials.

5 Disadvantages of Alternative 2:

6 1. Implementation of system-wide conveyance improvements with the 7 attendant inclusion of all water agencies in the region requires a more 8 general consensus on equitable water resource allocation than has 9 occurred historically.

10 2. Implementation of Alternative Objective 2 may require statutory changes 11 in the states of Texas and New Mexico to provide the necessary 12 authority for the regional water commission to operate the improved 13 system and to manage the water resource.

14 Alternative Objective No.3

15 Advantages of Alternative 3:

_16 1. Provides EPWU water for treatment and distribution that is not 17 degraded in quality by prior use within the Rio Grande Project.

18 2. Provides security against contamination during conveyance.

19 3. Provides a high degree of flow control.

20 Disadvantages of Alternative 3:

21 1. This alternative does not provide region-wide surface water resource 22 improvements.

2. The project construction cost per unit volume of water delivered is the highest of the alternatives considered.

129 1 Costs

2 Capital costs and the costs of conveyance per unit volume of water are 3 parameters which will certainly be of assistance in the evaluation of the 4 different alternatives. These costs were discussed previously, and several 5 tables were presented showing their detailed calculation. A summary of these 6 costs is shown in Table 21:

Table 21

Capital and Conveyance Costs

Alternative Capital Cost Conveyance Cost per No.lPeriod of acre-foot Operation

I $332,020,000

2005 to 2014 $67.37

2015 to 2034 $67.01

2035 to 2054 $62.78

2 $376,542,000

2005 to 2054 $37.39

2a $540,937,000

2005 to 2054 $53.78

3 $398,339,000

2005 to 2014 $130.24

2015 to 2034 $102.82

2035 to 2054 $90.68

7 As noted previously, although not the lowest in capital cost, Alternative 2 8 yields the lowest cost per unit volume of water conveyed.

9 On the basis of water treatment plant capital costs and treatment capacities 10 discussed earlier for water treatment plants in Las Cruces and Anthony, -U capital costs per unit volume oftreated water were detennined. The costs 12 found are shown in Table 22.

130 Table 22

Water Treatment Plant Cost

Plant/Facility Capital Cost Unit Cost per Acre Foot Las Cruces

2015 Facilities $130,100,000 $295

2035 Upgrade $268,400,000* $282

Anthony

2015 Facilities $310,100,000 $167

2035 Upgrade $373,900,000* $250

1 *The 2035 upgrades reflect costs based on a 2015 investment with inflation of 2 3%.

3 Water Budget Analysis -4 Estimated impacts to the Rio Grande hydrologic system from just downstream 5 of Caballo Dam to upstream of American Dam resulting from the three 6 proposed alternatives were developed from water budget analyses. Associated - 7 with quantitative impacts are impacts to water quality resulting from the 8 alternatives. These impacts were estimated using mass budgets for IDS. The 9 water and mass budgets were constructed in two reaches. Reach 1 represents -10 the Rincon Valley and Reach 2 represents the Mesilla Valley upstream of 11 American Dam. Impacts are assessed by comparing the water and mass 12 budget for each of the alternatives at 2015 demand levels against the Baseline -13 representing existing conditions. 14 Analysis of the system behavior was performed for ''Normal,'' "Average," and 15 "Dry" water supply conditions. The results from these analyses were 16 combined to develop a "Composite" scenario. Results for only the composite 17 scenario are presented. Key terms from the water budget analyses for the 18 Baseline, Alternative I, Alternative 2, and Alternative 3 by reach are 19 presented in Table 23. Also shown for each term are the differences between 20 each alternative and the Baseline. A similar table, Table 24, presents the 21 results of the mass budget analyses and the difference between each alternative --22 and the Baseline.

131 I Shown in the last row of Table 23 is the estimated deficit in full supply for - 2 2015 demands from surface water sources for each alternative. The deficit 3 was divided between the New Mexico and Texas water users on a 58 percent, 4 42 percent basis. Upstream of American Dam, the analyses assumed that the 5 deficit would be made up by ground water pumping. Downstream of 6 American Dam, the deficit could also be made up by ground water pumping. 7 Both upstream and downstream of American Dam, depending on the 8 alternative, additional supply could be developed through capturing and 9 blending return flows in the river. Reduction in demand through, for example, 10 retirement of agricultural land would also be a means of reducing the deficit in 11 surface water supply.

12 A further distillation of the results for the Baseline and each Alternative is 13 provided in Table 25. This table specifically focuses on the flow in the river -14 and the water quality, expressed as a concentration, at key locations in the 15 system. As shown by these results, each alternative has significantly different 16 impacts on the Rio Grande both from a quantity and quality stand point.

132 TableD Water Budget Summary

BASELINE ALTERNATIVE 1 ALTERNATIVE 1 ALTERNATIVEJ Composite Water Supply Scenario EotImated EstImated PARAMETER Amount 1.;.·.I.·.I··... ;g_~I.··.i-·~•• ~1 =~ Amount (1000 of) E :) ..•.• (1000 of) ~each 1 (Rincon Valley)

Ground water boundary flux in 3.0 3.0 3.0 3.0 Ground water boundary flux out 0.3 0.3 0.3 0.3 M&I ground water pumping 0.9 0.9 0.9 0.9 Agricultural ground water pumping 18.9 23.9 30.1 20.9 Deep percolation 14.6 14.6 14.6 14.6 Ground water flow to drains 8.4 8.4 8.4 8.4 Canalllateral seepage 39.3 39.3 25.8 39.3 __ Net river seepage (into alluvial aquifer) -25.2 -25.2 -25.2 -25.2 Change in ground water storage 2.1 -2.9 -35.6 0.2 River inflow 643.9 643.9 643.9 643.9 River outflow 612.2 286.0 11.9 351.8 Main supply canal/pipeline inflow 0.0 331.2 686.3 262.4 Main supply canal/pipeline outflow 0.0 330.5 625.1 262.4 River flow to M&I 0.0 0.0 0.0 0.0 Main supply canaVpipeline flow to M&I 0.0 0.0 0.0 0.0 I River flow to agriculture 86.0 80.9 0.0 84.0 I Main supply canal/pipeline flow to agriculture 0.0 0.0 61.1 0.0

I.: ...... teach 2 (Mesilla Valley)

Ground water boundary flux in 0.3 0.3 0.3 0.3 Ground water boundary flux out 0.1 0.1 0.1 0.1 M&I ground water pumping 46.2 6.5 11.0 4.5 Agr. ground water pumping from alluvial aquifer 61.9 77.1 ...... 97.6 68.0 Agr. ground water pumping from Mesilla Bolson 41.3 51.4 62.6 45.3 Deep percolation 67.2 67.2 67.2 67.2 Ground water flow to drains 85.0 85.0 85.0 85.0 _ CanalJlateral seepage 163.8 163.8 143.8 163.8 Net river seepage (into alluvial aquifer) 59.3 59.3 59.3 59.3 Change in ground water storage 0.0 0.0 I , ..... 0.0 0.0 Net leakance to Mesilla Bolson 143.7 128.5 I 88.0 137.6 - River inflow 612.2 286.0 11.9 351.8 River outflow 358.9 58.0 135.7 108.6 Main supply canal/pipeline inflow 0.0 330.5 625.1 262.4 _ Main supply canaVpipeline outflow 0.0 229.8 232.3 160.7 Ri ver flow to M&I 0.0 0.0 0.0 0.0 Main supply canal/pipeline flow to M&I 0.0 39.7 35.2 41.7 River flow to agriculture 377.1 351.8 0.0 367.0 - Main supply canaVpipeline flow to agriculture 0.0 0.0 297.6 0.0 Deficit in full supply from surface water supply 0.0 58.2 135.4 23.3

1/18/95 Table 24 Mass Budget Summary

BASELINE ALTE~~~~}, ALTE~~~~2 ALTE~.A_.. TIVEJ ComposIte Water Supply Seenario Estimated Estimated .•...... """ Estimated ••••...... •. Estimated '/"; .."~ Amount Amount i)i< .•...•. '" \/ PARAMETER Amount Ii· Amount < (1000 tons) (1000 tons) I> ;{< (1000 tons) IU;· (1000 tons) Reach 1 (Rincon Valley) •••••••. / River inflow 478.6 493.3 498.5 500.5 Canal waste return 8.2 8.2 8.2 ..... 8.2 M&I return flow 0.4 0.4 0.4 0.4 Drain flow to river 25.5 25.5 25.5 25.5 Tributary inflow 11.1 11.1 11.1 1\.1 River flow to M&I 0.0 0.0 0.0 0.0 River flow to agriculture 65.1 60.2 0.0 63.1 Main supply canaI/pipeline inflow 0.0 272.8 534.9 228.5 Net river seepage (into alluvial aquifer) -23.8 -23.8 -23.8 -23.8 River outflow 482.5 229.3 31.9 277.8

Reach 2 (MesiDa Valley) I .. ...•. . River inflow 482.5 229.3 31.9 277.8 Canal waste return 23.9 25.4 22.8 28.0 '., ..... M&I return flow 25.9 25.9 25.9 25.9 Drain flow to river 204.5 214.5 25.9 261.9 Tributary inflow 27.2 27.2 27.2 27.2 River flow to M&I 0.0 0.0 0.0 0.0 River flow to agriculture 299.9 292.7 0.0 349.4 Net river seepage (into alluvial aquifer) 55.8 66.1 125.1 78.8 River outflow 408.2 163.4 172.0 149.0 1<" ',-:.. \

6/22/94 1

Table 25

River Flow and Quality at Key Locations for Composite Water Supply Scenario

Location River Flow (1000 af) IDS (mglI)

Baseline AIt 1 AIt2 AIt3 Baseline AItl AIt2 AIt3

Downstream 643.9 643.9 643.9 643.9 500 600 1) 600 1) 600 1) of Caballo

Leasburg 612.2 286.0 11.9 351.8 600 600 2000 600

Upstream of 358.9 58.0 135.7 108.6 800 2000 1000 1000 American

2 1) Revised release pattern from Caballo Reservoir simulated in alternative 3 analyses resulted in increase in estimated IDS concentration below Caballo.

4 Surface Water Loss Evaluation

5 The single surface water impact analysis is presented as Table 26. These 6 results tabulate the losses to the usable surface water due to seepage and 7 evaporation. The seepage loss element of surface water losses is not 8 necessarily a system loss, but is presented for evaluation as surface water that 9 will be unavailable for application to irrigation or M&I uses.

10 The analysis in Table 26 is presented for the purpose of illustrating the 11 comparative values of "loss" for the baseline (no action) and the three 12 alternatives. As applied here, the term "loss" means surface water that is 13 unavailable for surface water applications. The actual loss is that water which 14 evaporates since the seepage quantities become ground water.

15 Summary of Aquifer Effects

16 The water budget analysis shows the effect of the baseline and three 17 alternative objectives operating scenarios on the surface water and shallow 18 ground water in the Mesilla Valley. This information is key to the 19 determination of the system-wide effects of the alternatives on the three 20 resource elements of the project: the Mesilla Basin, the Hueco Basin, and the 21 Rio Grande. By extrapolation, the impacts of stream flow in the river and -22 canals, and the long-term gain/loss storage in the aquifers can be determined.

135 Table 26 Surface Water Loss Analysis for Average Year All values in acre-feet x 1000 per year

Water Budget Reach Rio Grande Canal Rio Grande Canal Total Loss Scenario Seepage Seepage Evap.-Precip. Evaporation Seep.lEvap.

Baseline One -32.6 41.2 4.1 0.3 13.0 Two 71.4 161.2 5.6 U.8 250.0

Total 38.8 202.4 9.7 12.1 263.0

Alternative 1 One -32.6 41.2 4.1 0.3 13.0 Two 71.4 161.2 5.6 U.8 250.0

Total 38.8 202.4 9.7 12.1 263.0

Alternative 2 One -32.6 27.0 4.1 0.3 -1.2 Two 71.4 141.5 5.6 U.8 230.3

Total 38.8 168.5 9.7 12.1 229.1

Alternative 3 One -32.6 41.2 4.1 0.3 13.0 Two 71.4 161.2 5.6 U.8 250.0

Total 38.8 202.4 9.7 12.1 263.0

6/22/94 1 The two aquifer analyses are presented as sununary diagrams (Figures 47 and 2 Figure 48) to illustrate the effects on the supply resources. The results for 3 each aquifer are presented as a plot of a spreadsheet analysis of the annual 4 gainlloss of storage in that aquifer resulting from "no action" (baseline) and 5 the three alternatives.

6 The Mesilla Basin

7 This aquifer is located within the Rio Grande Rift in the reach of the river 8 starting immediately below Caballo Dam. It extends down the river valley to 9 "the pass" at El Paso near the American Dam where the boundaries of New 10 Mexico, Texas, and Chihuahua meet. This aquifer is stream-related inasmuch 11 as flows of surface water in the river channel freely recharge the aquifer and -12 vice-versa, depending on hydraulic gradients. If ground water is withdrawn 13 from the aquifer, causing a surface differential with the river, water will tend 14 to recharge the aquifer. Conversely, if the surface of the aquifer rises above - 15 the stream bed of the river, ground water will tend to flow to the surface of the 16 river bed.

17 Figure 47 shows a plot of net losses in the aquifer storage of the Mesilla Basin 18 vs. time for each alternative and the baseline (no action). The assumptions in 19 making these projections are:

-20 1. The present state of the aquifer is stable. That is, all withdrawals are 21 in balance with the recharge rate, and withdrawals in excess of 22 mountain front recharge are replenished by seepage from the stream -23 beds of the river and canals. 24 2. The mountain front recharge is presented as a constant representing -25 the estimated average recharge due to watershed precipitation. 26 3. All M&I well pumpage of ground water is from the Mesilla. 27 4. Forty percent of all agricultural well pumpage is from the Mesilla, 60 28 percent is from shallow aquifers.

-29 5. The water required to maintain and protect the aquifer will naturally 30 flow from seepage sources of surface water if available.

137 Mesilla Basin Loss Rate vs. Time

C2' ~ , _- '/ "L" -';'1' :'F, ;~,(~:~.n;r~f'.,..[:·~, ~ -50 -f/J of/J ....J ~ C "m -100 ~------CJ +-" Q) Z

-150 ~------

2005 2010 2015 2020 2025 2030 2035 Year Figure 47 I The Hueco Basin

2 The Hueco Basin is markedly different from the Mesilla. It is a closed basin 3 on three sides, and it crosses below the flood plain of the Rio Grande, 4 terminating in the Republic of Mexico on the fourth (southern) side. The bulk 5 of the basin lies east of the Hueco Tanks outcropping. The northern end is in 6 Dona Ana County, New Mexico. At present, approximately 60 percent of the 7 municipal water supply of the City of EI Paso is extracted by wells from this 8 aquifer. This aquifer is in serious jeopardy of total depletion if actions are not 9 taken to stop and reverse present trends.

-10 The extrapolations of the results of the water budget analysis are applied by 11 assuming the surface water availability to EPWUIPSB identified in the 12 alternatives will be applied against the base demand requirements of the - 13 utility, and the existing well fields will be utilized to provide the peak 14 requirements during the summer months when water demands exceed the base 15 capacity of the water treatment plants. This strategy will reduce the aquifer -16 withdrawal by more than two-thirds.

17 The assumptions of this analysis are:

18 1. The natural mountain front recharge is represented as a constant 19 representing the average annual recharge due to precipitation on the 20 watershed.

21 2. The recharge attributable to the injection of tertiary treated waste 22 water from the Fred Hervey Water Reclamation plant will continue at -23 the present capacity.

24 3. The out-flux of the aquifer is assumed to be the projected well -25 pumpage by Ciudad Juarez for its municipal water supply. The 26 baseline Juarez water demand from the aquifer is modified for the 27 alternative analyses by a reduction equivalent to applying the full -28 1906 Convention allotment for Mexico (60,000 af/yr) to municipal 29 purposes.

30 The plot shown on Figure 48 represents the Hueco Basin storage impacts. To 31 be noted is that even with the most rigorous application of surface water to 32 municipal purposes by the City of EI Paso (EPWU), full stability of reservoir 33 storage is not achieved.

34 The extraction of ground water from the Hueco Basin by Juarez is not within 35 the jurisdiction of the United States entities. This fact would indicate that -36 continued cooperative ground water conservation planning efforts with the 37 Republic of Mexico should be pursued.

139 Hueco Basin Loss Rate vs. Time o

Induced Recharge Requirement -100 i$;- '5i~~:t1"t:'" oc _?,_,_~ -~-t;' .t'f.~~~~l!1J:~~P''1~~~imlr'!'!l:~E~1~.,~t;lWiH~: • 3 mi::t. "~f~",~'Ii>li!m;l"li!"_"'l'>'-~" Alternatives 1, 2 & 3 ~ -200 ~ I y ---(J) (J) ------.9 -300 2 ~ Alternatives 1, 2 & 3 c "as ------(!) -400 ------Q) - z aseline -500 ...... -600 2005 2010 2015 2020 2025 2030 2035 1. Assumes Conversion of Mexican RGP Allotment of 60 AFfYR to Year M & I Use. 2. Altematives impact if Mexico continues present trends of ground water for M & I. 3. Alternatives impact if Mexico converts growth demand beyond Figure 48 year 2000 to surface water supply. 1 Restoration or stabilization of the Hueco Basin will be dependent on induced 2 recharge by means of spreading or well injection of surface water. The 3 quantity, or rate of recharge required to attain stability is indicated in Figure 4 48 as the difference between the selected alternative and zero loss.

5 Water banking and aquifer storage are addressed under the Additional 6 Considerations section of this report.

141 List of References

I 1. Boyle Engineering Corporation, 1990, EI Paso Water Resource 2 Management Plan Study Phase I Completion Report, Draft.

3 2. Boyle Engineering Corporation, 1990, EI Paso Water Resource 4 Management Plan Study Phase IT Completion Report, Draft.

5 3. Boyle Engineering Corporation, 1992, EI Paso Water Resource 6 Management Plan Study Phase III Completion Report, Final Report.

7 4. Boyle Engineering Corporation, Engineering-Science, Inc., New 8 Mexicolfexas Joint Conveyance Facility for Rio Grande Project Water 9 Phase I Final Report

10 5. Engineering-Science, Inc., 1991, Surface Water Supply Alternatives for 11 the City ofEI Paso and Southern New Mexico Users, Final Report.

12 6. Engineering-Science, Inc., Regional Water Supply Plan for the Lower Rio 13 Grande Valley above Leasburg, Final Report, April 1994.

14 7. Frenzel, P.F. and C.A. Kaehler, Geohydrology and Simulation of Ground­ 15 Water Flow in the Mesilla Basin, Dona Ana County, New Mexico, and EI 16 Paso County, Texas, U.S. Geological Survey, Open-File Report 88-305, 17 1990.

18 8. Giacinto, l F., 1988, An Analysis of Proposed Pumpage Effects of the -19 Upper Aquifer of the Mesilla Valley, New Mexico, University of Arizona, 20 Department of Hydrology and Water Resources.

-21 9. Hamilton, S. L., and T. Maddock III, 1993, Application ofa Ground­ 22 water Flow Model to the Mesilla Basin, New Mexico and Texas, 23 University of Arizona, Department of Hydrology and Water Resources.

24 10. Hernandez, lW., C.L. Mapel and P.I. Enis, 1987, Community 40-Year 25 Water Plan for the County of Dona Ana, New Mexico, 1980-2030, New 26 Mexico State University, Department of Civil Engineering and the 27 Department of Agricultural Economics.

28 II. Leedshill-Herkenhoff, Inc., Water System Master Plan Volume I & II For: 29 City of Las Cruces, New Mexico, March 1988.

30 12. Maddock, T. III, and Wright Water Engineers, Inc., An Investigation of -31 the Effects of Proposed Pumping in the Lower Rio Grande Declared 32 Basin, December 1987.

_33 13. New Mexico Environment Department, 1991, Regulations Governing 34 Water Supplies

142 1 14. New Mexico Water Resources Research Institute, 1990, A Compilation of 2 Trace Metal Values in Water and Sediments Collected along the Rio 3 Grande and its Tributaries in New Mexico, WRRI Report No. M22.

4 15. New Mexico Water Resources Research Institute, 1976, Rio Grande 5 Water Quality Base Line Study 1974-75 for the Rio Grande, Canals and 6 Associated Drains from San Marcial, New Mexico to Fort Quitman, 7 Texas, Summary Report, Appendix B, and Appendix C, WRRI Report 8 No. 064.

9 16. New Mexico Water Resources Research Institute, 1988, Water Supply _10 and Demand for New Mexico 1985-2030-Resource Data Base, WRRI 11 Report No. M18.

12 17. Bureau of Business and Economic Research, University of New Mexico 13 Population Projections for New Mexico Counties: 1990-2010.

14 18. Shosted, G.E., 1987, Application of the Mixing Cell Model to Analyze _. 15 Water Quality Relationships, University of Arizona, Department of 16 Hydrology and Water Resources.

_ 17 19. Sorensen, E.F., 1982, Water Use by Categories in New Mexico Counties 18 and River Basins, and Irrigated Acreage in 1980, New Mexico State 19 Engineer, Technical Report 44, 51 p.

20 20. U.S.B.R Rio Grande Project Historical Records for 1951, 1967, 1970, 21 1971, 1980, 1984, and 1988.

-22 21. U.S.B.R. Rio Grande Project Annual Operating Procedures for 1984, 23 1985, 1986, 1987, 1988, 1989, 1990, and 1991.

-24 22. Wilson, B.C., 1992, Water Use by Categories in New Mexico Counties 25 and River Basins, and Irrigated Acreage in 1990, New Mexico State 26 Engineer, Technical Report 47, 141 p.

27 23. Wilson, C.A., RR. White, B.R Orr, and R.G. Roybal, 1981, Water 28 Resources of the Rincon and Mesilla Valleys and Adjacent Areas, New 29 Mexico: New Mexico State Engineer, Technical Report 43,514 p.

30 24. Parkhill, Smith and Cooper, Inc. Jonathan W. Rogers Water Treatment 31 Plant. Pre-design Report, City ofEI Paso. February 1990.

32 25. American Water Works Association Water Treatment Guidelines, 33 American Water Works Association, 1990.

143 I 26. Texas Water Commission Rules and Regulations, 1992, Texas Water 2 Commission.

3 27. Boyle Engineering Corporation, 1994, Water Facilities Master Plan.

144 Conjunctive Water Resource Management Technical Data Report-Volume I

Contract No. 94-483-017

The following maps are not attached to this report. Due to their size, they could not be copied. They are located in the official file and may be copied upon request.

Conjunctive Water Resource Management and Aquifer Restoration Study­ Northern Half Figure 3

Conjunctive Water Resource Mamigement and Aquifer Restoration Study­ Southern Half Figure 3

Please contact Research and Planning Fund Grants Management Division at (512) 463 -7926 for copies.