JSAI TM ASR Evaluation 2nd Draft November 3 JOHN SHOMAKER & ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
2611 BROADBENT PARKWAY NE DRAFT
ALBUQUERQUE,NM 87107
505-345-3407; 505-345-9920 FAX
www.shomakerxom
i -
TECHNICAL MEMORANDUM
To: Adrienne Widmer, P.E., Las Cruces Utilities awidmer@las-cruces.org
From: Andrew P. Feltman, C.P.G., P.G., Senior Hydrogeologist
Annie McCoy, C.P.G., Senior Hydrogeologist
Date: November 3, 2020
Subject: Evaluation of ASR Potential for Reclaimed Wastewater, City of Las Cruces,New
Mexico—Draft 2
This Technical Memo details John Shomaker & Associates, Inc. (JSAI)'s desktop
investigation of potential for Aquifer Storage and Recovery (ASR), also referred to as
Underground Storage and Recovery (USR), in the City of Las Cruces (City). In this case, the
source of water will be reclaimed wastewater from the East Mesa Water Reclamation Facility
(EMWRF) or from the West Mesa Wastewater Treatment Plant.
For this study, JSAI evaluated the potential for ASR application of the reclaimed
wastewater with respect to aquifer hydraulic properties and availability of existing recovery
wells, with the goal of identifying one or more sites with good potential for ASR. This
Memorandum relates to Task 4 of the implementation of the 10-Year Water Development
Action Plan.
Aquifer Storage and Recovery
ASR is a process in which excess water is stored in aquifers and later recovered via
groundwater supply wells. Preferred injection locations maximize storage and limit losses, such
as to surface-water systems, the regional aquifer, or pumping by other water rights holders.
Water may be injected directly into the aquifer using existing or purpose-built wells. Water can
be injected and recovered through the same well, or the injection well can work in tandem with
a recovery well or wells. Alternatively,water may be allowed to infiltrate from above the water
table through settling basins or through "dry wells" - uncased large-diameter boreholes
backfilled with gravel.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 2 - DRAFT November 3, 2020
Overview of Regulatory Process
The City is interested in pursuing ASR as an approach to alternate water supply with the
support of State agencies. The New Mexico Environment Department Ground Water Quality
Bureau (LAMED GWQB) and the New Mexico Office of the State Engineer (NMOSE) are the
regulatory agencies involved with reuse and ASR projects.Permitting with NMED and NMOSE
would be subject to public notice and protest.
Per New Mexico Statues Annotated (NMSA) Section 72-5A-4, no governmental entity
may perform ASR without a permit from the NMOSE. The regulations for performing ASR are
described in New Mexico Administrative Code(NMAC) 19.25.8.The NMED GWQB regulates
discharges to the ground surface and groundwater per the NMAC 20.6.2. A Notice of Intent to
Discharge must be filed before any discharge is made. A Discharge Permit must be obtained for
all discharges into the groundwater system, and many discharges to the surface.
Water discharged into the groundwater system must meet defined standards. The Code
also indicates that wells used for aquifer storage would be categorized as Class V Underground
Injection Control wells. A Class V well completion is similar to that required by the NMOSE
for an artesian well. However, neither of the purpose-built ASR wells completed by the City of
Rio Rancho, and the Albuquerque Bernalillo County Water Authority, were completed in this
fashion. Therefore, it is likely that ASR wells completed by the City would not have to be built
as Class V injection wells, and could be constructed like traditional water wells.
The NMOSE regulations for performing ASR include a pre-application meeting and
project proposal that requires the submission of an essentially complete application. Pre-
application documents include, but are not limited to,water rights, description of source water,
site location, description of pilot project, water-quality parameters, potential hazards, and
hydrogeologic information.
Subsequent to that meeting, assuming the proposal is viewed favorably by the State
Engineer, the next step in the application process is a pilot project. The objective of the pilot
project is to implement a demonstration project to collect hydrologic and hydrogeologic data in
order to evaluate the project at full-scale implementation. The pilot project would require
monitoring wells and water-quality sampling.
The results of the pilot project are presented in a capability report. This report includes
the following components:
• Executive Summary
• Project Objectives
• Evidence of Technical Capability
• Evidence of Financial Capability
• Evidence of Hydrologic Feasibility
• Area of Hydrologic Effect of Proposed Artificial Recharge, Storage, and Recovery
Proj ect
• Hydrogeologic Characterization of the Area of Hydrologic Effect
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 3 - DRAFT November 3, 2020
• Evaluation of Impairment to Water Rights and Harm to Owners of Land Within the
Area of Hydrologic Effect
• Validity of the Source Water Right
• Site Description
• Facility Description
• Facility Design
• Facility Operation and Maintenance
• Hydrogeographic Characterization of the Area of Hydrologic Effect
• Effects Created by a Underground Storage and Recovery Project
• Water Level Monitoring Plan
• Description of Water Quality Monitoring and Treatment Plans Required by a State
or Federal Agency or Department
• Contingency Plan
Based on the information provided in the capability report, the NMOSE will establish a
storage account. A permittee may recover only the amount of water,as recognized and approved
by the NMOSE,that has reached the aquifer,remained within the area of hydrologic effect, and
may be recovered without impairment to water rights or harm to land owners within the area of
hydrologic effect.
A description of the full-scale project is then required to be submitted. Submissions
would include, but are not limited to, pilot study results, groundwater modeling to assess full-
scale implementation, description of project facilities, operation and maintenance, and other
permits. Water stored in an ASR program is subject to an annual fee in the amount of fifty cents
($0.50)per acre-foot of water placed in storage during the period of time covered by the annual
report.
The New Mexico State Water Plan indicates the State's support for the development and
permitting of ASR projects as a water supply and demand strategy (NMISC, 2018). However,
the State's current regulatory framework poses major challenges that may discourage ASR as
an approach for several reasons:
• The State requires discharge permits issued for ASR projects to meet groundwater
discharge water quality standards set forth in NMAC 20.6.2.3103.
• Water injected directly into the aquifer must meet State primary drinking water
standards, per the Underground Injection Control section in the Water Quality Control
Commission Regulations (NMAC 20.6.2.5000). This level of water treatment for
recharge water can be cost-prohibitive.
• If the existing concentration of any water contaminant in groundwater is in conformance
with the discharge standard(NMAC 20.6.2.3103), degradation of the groundwater up to
the limit of the standard is allowed; however, if the existing concentration of any water
contaminant in groundwater exceeds the standard, no further degradation of the
groundwater beyond the existing concentration is allowed.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 4 - DRAFT November 3, 2020
• Extremely comprehensive demonstrations and pilot testing, as may be required, can also
be cost-prohibitive.
• NMAC 19.25.8.22.F indicates that ASR application must have a valid water right for
recharge water which meets the Burden of Proof. The applicant has the burden of
proving:
A. the applicant has the technical and financial capability to construct and operate
the project;
B. the project is hydrologically feasible;
C. the project will not impair existing water rights or the state's interstate
obligations;
D. the project will not be contrary to the conservation of water within the state;
E. the project will not be detrimental to the public welfare of the state;
F. the applicant has a valid water right for the recharge water quantified by one of
the following legal processes:
(1) a water rights adjudication;
(2) a consent decree;
(3) an act of congress,including a negotiated settlement ratified by congress;
(4) a contract pursuant to the Colorado River Storage Project Act, 43 U.S.C.
Section 620 (1986 and Supp. 1999); or
(5) an agreement with an owner who has a valid water right subject to an
application for a change in purpose,place of use or point of diversion
G. the applicant will obtain all other permits for the project required by state and
federal law. A project shall not be operated under the Act until an applicant has
obtained all other state and federal permits required for the project; and
H. the project will not impair water rights or cause harm to owners or land within
the area of hydrologic effect.
A licensed water right signed by the State Engineer is not included as one of the legal
processes listed in NMAC. The City of Santa Fe is currently in talks with the NMOSE in an
attempt to reinterpret the Burden of Proof requirement to include licensed water rights. The
water coming into the EMWRF is a mix of East Mesa Well Field (some under LRG-430, some
under East Mesa permit), Moongate water, former Jornada Water Company (LRG-47 et al. is a
licensed right), and NASA water. The amount from each source is not currently measured.
The City could benefit from exploring other approaches to ASR, possibly with other
levels of water treatment, with cooperation and support from State regulatory agencies. The
requirements listed above are in contrast to the more supportive regulatory framework for ASR
in Texas, just 20 miles away from Las Cruces, and it would appear that New Mexico could
benefit from examining the regulatory framework in other states such as Texas where water
supply has already benefited from a greater number of successful ASR projects. New Mexico's
ASR regulations could be reviewed and modified accordingly for a more streamlined process,
and for variances based on local hydrogeologic conditions.
JSAI is engaging in discussions with NMED and NMOSE that precede the pre-
application process. We are discussing potential limiting factors, such as water treatment
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 5 - DRAFT November 3, 2020
requirements and water rights. These discussions are intended to give the State agencies an
opportunity to support the City with an approach to ASR that would be viable,given the current
regulatory framework.
Hydrogeologic Setting
The City of Las Cruces is situated in the Mesilla Basin along the Rio Grande. It extends
into the West Mesa within the Mesilla Basin, and into the East Mesa area in the southern part of
the Jornada del Muerto Basin. The Mesilla Basin and Jornada del Muerto Basin represent two
sub-basins within the Lower Rio Grande Basin.These basins formed through faulting caused by
the extension of the Rio Grande Rift, and were filled with sediment from surrounding highlands.
The City relies on groundwater from its Valley Well Field (including the Interstate-25 Corridor
area and Valley area) and West Mesa Well Field in the Mesilla Basin, and East Mesa Well Field
in the Jornada del Muerto Basin,for its potable water supply(see Figure 1). Wells in these areas
produce water from the alluvial deposits of the Upper and Middle Santa Fe Group, as well as
the post-Santa Fe Group channel and floodplain deposits of the Rio Grande (Hawley and
Lozinsky, 1992).
The Mesilla and Jornada del Muerto Basins are hydraulically connected by a thin,
discontinuous layer of saturated sediments that overlies the bedrock high that separates the two
basins in some places. Some groundwater from the Jornada del Muerto Basin "spills" over this
buried horst into the Mesilla Basin (JSAI, 2002). The horst acts as a partial barrier to
groundwater flow, resulting in higher groundwater elevations in the Jornada del Muerto Basin
to the east than in the Mesilla Basin to the west. The groundwater table is above the top of the
horst in some areas south of U.S. Highway 70, but north of the highway, the groundwater table
is below the top of the horst, largely restricting inter-basin groundwater flow in that region
(Woodward and Myers, 1997). Geothermal water wells up along faults that bound the Jornada
Horst, and can have significant local effects on groundwater temperature and quality (Finch,
1999). Figure 2 is a geologic map of the northern part of the Mesilla Basin and southern part of
the Jornada del Muerto Basin, and Figure 3 is a southwest-to-northeast hydrogeologic cross-
section of the City of Las Cruces area.
Depth to water in the Mesilla Basin ranges from approximately 50 ft bgl in the Rio
Grande floodplain to 300 ft bgl in the western and east-central part of the basin (see Figure 3).
Analysis of water-level elevation contours (see Figure 4) shows that localized regions of water-
level decline are developing beneath the communities of Dona Ana and Las Cruces. A cone of
depression develops where groundwater water is being pumped out faster than water from other
parts of the aquifer can flow in to replace it. Groundwater flow in the Mesilla Basin is generally
to the southeast, with groundwater flowing from higher elevations to lower elevations, parallel
to the course of the Rio Grande. There is also a steep water-table slope from the surrounding
hills down into the basin-fill deposits (Wilson et al., 1981; Frenzel and Kaehler, 1990). The
average water-table gradient in the Valley is about 25 feet per mile (0.005 ft/ft). Recharge to
the Mesilla Basin is primarily from infiltration of surface water from the Rio Grande and
associated irrigation works.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 6 - DRAFT November 3, 2020
Depth to water in the Jornada del Muerto Basin ranges from about 100 to 600 ft bgl,with
the greatest depth in the area of highest basin-fill permeability (see Figure 3). The direction of
groundwater flow in the Jornada del Muerto Basin is generally to the west and south,toward the
Mesilla Basin (see Figure 3). The groundwater flow direction in the northern part of the basin
is to the northwest, where groundwater discharges toward the Rincon Valley. The gradient is
steepest in the mountains, and becomes flatter, about 5 to 8 feet per mile, in the western part of
the basin. In the very southern end of the basin,the flow direction is to the southwest(Shomaker
and Finch, 1996). Recharge to the Jornada del Muerto Basin is from infiltration of precipitation
and runoff from the San Andres and Organ Mountains east of the basin.
Groundwater elevation contours in the Rio Grande Valley of the Mesilla Basin are shown
in Figure 4. Groundwater elevation contours have not been drawn in the West Mesa Well Field
or East Mesa Well Field area of the Jornada del Muerto Basin due to scarcity of data.
Hydraulic Properties
The Mesilla and Jornada del Muerto Basins contain thick, unconsolidated Santa Fe
Group basin-fill sediments and Rio Grande flood plain alluvium. The hydraulic conductivity of
the basin-fill deposits is highly variable, but in general the younger sediments have higher
hydraulic conductivity and relatively good water quality (total dissolved solids concentration
below 1,000 mg/L), and typically the older sediments at depth have a lower hydraulic
conductivity, and poorer water quality (Hawley and Lozinsky, 1992).
The hydraulic properties of the aquifer are important in assessing the feasibility of an
aquifer for storage and recovery of surplus water. The efficiency of an aquifer to receive water
for storage and to recover stored water depends in part on hydraulic conductivity and
transmissivity (hydraulic conductivity times aquifer thickness). If the aquifer targeted for ASR
has a transmissivity that is too low,it is difficult to store large volumes of water without creating
discharge at the surface, or in the case of relatively deep aquifers, creating the need to inject the
water under high pressure. However, aquifers with very high transmissivity can carry injected
water too far away from the well, reducing the efficiency of water recovery. Proving the ability
to reclaim stored water may be critical for ASR permitting with the NMOSE. In general,Hawley
and Lozinsky(1992) estimate the range in hydraulic conductivity of the Middle Santa Fe Group
as 0.3 to 30 ft/day, and the Upper Santa Fe Group and Rio Grande floodplain sediments as 30 to
300 ft/day. Table 1 provides a summary of hydraulic properties for various portions of the
Mesilla Basin aquifer.
Typically, an aquifer with horizontal hydraulic conductivity exceeding 5 ft/d can yield
several hundred gpm to wells,provided the aquifer has adequate saturated thickness. As shown
in Table 1, the Rio Grande alluvium has a very high hydraulic conductivity but water is present
at shallow depth, which can lead to inefficient recovery of injected water and loss of the water
to other users and the surface water system (JSAI, 2002). The remaining portions of the Mesilla
Basin, and the Jornada del Muerto Basin, appear to have adequate hydraulic properties for ASR
proj ects.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 7 - DRAFT November 3, 2020
Table 1. Summary of hydraulic properties of the Mesilla Basin aquifer in selected areas
(modified after JSAI,2002)
specific hydraulic
depth to capacity conductivity transmissivity
water, well yield, of wells, of aquifer, of aquifer,
area ft bgl gpm gpm/ft ft/day ft2/day
5 9d Rio Grande alluvium 10-25a 2,500+a 10-217a 1094d 12,600-15,200-
Valley Well Field 25 to 320 500 to 3 to 30' 2 to 150h 2,7 10 to 19,3 00 h
2,000'
upper 200 ft of aquifer 20 to 150 h 4,000 to 30,000''
aquifer from 200 to 600 ft 2 to 26.5 h 800 to 10,500''
aquifer from 600 to 1,200 ft 1.7 to 13 h 1,000 to 7,800 h
a Wilson et al., 1981 ft bgl feet below ground level
b Hamilton and Maddock,1993 gpm/ft gallons per minute per foot
Conover,1954 W/day feet squared per day
a Frenzel and Kaehler, 1990
9 Nickerson,1989
b Weeden and Maddock, 1999
'JSAI,2017
Description of Reclaimed Wastewater
City of Las Cruces wastewater is treated at three facilities: (1) Jacob A. Hands
Wastewater Treatment Facility, (2) East Mesa Water Reclamation Facility (EMWRF), and (3)
West Mesa Wastewater Treatment Plant. Reclaimed water produced from the West Mesa
Wastewater Treatment Plant and EMWRF represent water sources that are not fully utilized,
and which are potential sources for alternate supply through ASR application.
The Jacob A. Hands Wastewater Treatment Facility produces approximately
3,030,800,000 gallons(9,300 acre-feet)of effluent annually.All treated effluent from the facility
is discharged as return flow to the Rio Grande.
The West Mesa Wastewater Treatment Plant produces approximately 28,233,060
gallons (87 acre-feet) of effluent annually. Most of this is currently used for sprinkler-irrigation
of native vegetation in the West Mesa Industrial Park,with the remainder being land-applied.
The EMWRF effluent is currently used, in part, for landscape irrigation, dust
suppression, and fire hydrants. The EMWRF has a capacity of 1,000,000 gallons per day (about
1,121 acre-feet/year). Peak summer demand from the facility is about 700,000 gallons per day;
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 8 - DRAFT November 3, 2020
however, the facility must ramp down in winter when there is very little demand for the water.
Average water reuse diversions for the winter months of November through March represent
about 60 percent of average water reuse diversions for the summer months of April through
October, and reflect the lack of demand for reclaimed water during the winter months. Under-
utilization of the facility during the winter months equates to about 350 ac-ft/yr.
The EMWRF reclaims water to relatively high quality, though not necessarily to
NMED/Drinking Water Bureau (NMED/DWB) drinking water standards. Table 2 includes
recent EMWRF effluent water quality data provided by the City, compared with NMED
groundwater discharge standards and drinking water standards.
Table 2. Summary of ENMRF effluent water quality
groundwater NMED/DWB
time no. of drinking
parameter period samples units min max discharge water
standard standard
TDS 2019- 20 mg/L 640 1,750 1,000 500a
2020
chloride 2019- 20 mg/L 205 374 250 250 a
2020
sulfate 2017 4 mg/L 151 211 600 250 a
2020
nitrate as N 2019- 20 mg/L 0.8 15.4 10 10
2020
ammonia 20 20
2020 19-
20 mg/L 0.21 7.6 ns ns
TKN 2019- 20 mg/L 0.94 11.7 ns ns
2020
fluoride 2017 4 mg/L 0.26 0.47 1.6 4
2020
aluminum 2017 3 mg/L 0.0072 0.014 5 0.05 to 0.20'
2019
antimony 2017 2019 2 mg/L na <0.005 0.006 0.006
arsenic 2017 3 mg/L 0.0019 0.0028 0.01 0.010
2019
barium 2017 3 mg/L 0.059 0.068 2 2
2019
beryllium 2017 2 mg/L na <0.001 0.004 0.004
2019
cadmium 2017 6 mg/L na <0.002 0.01 0.005
2019
chromium 2017 3 mg/L na <0.005 0.05 0.1
2019
cobalt 2017 3 mg/L na <0.001 0.05 ns
2019
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 9 - DRAFT November 3, 2020
copper 2017 3 mg/L 0.0018 0.0036 1 1.3
2019
iron 2017 3 mg/L <0.05 0.05 1 0.3 a
2019
lead 2017 3 mg/L na <0.0005 0.015 0.015
2019
manganese 2017 3 mg/L 0.028 0.038 0.2 0.05 a
2019
mercury 2017 3 mg/L na <0.0002 0.002 0.002
2019
molybdenum 2017 3 mg/L 0.005 0.006 1 ns
2019
nickel 2017 2019 3 mg/L 0.0014 0.006 0.2 ns
Silver 2017 3 mg/L na <0.0005 0.05 0.1 a
2019
thallium 2017 2 mg/L na <0.002 0.002 0.002
2019
uranium 2017- 2 mg/L 0.00331 0.00439 0.03 0.03
total 2018
zinc 2017 3 mg/L 0.021 0.044 10 5.0 a
2019
boron 2017 3 mg/L <0.50 0.271 0.75 ns
2019
selenium 2017 3 mg/L na <0.005 0.05 0.05
2019
cyanide 2017 3 mg/L na <0.02 0.2 0.2
2019
volatile
organics 2017- not
low-level 2019 6 mg/L na detected various various
EPA 624
Low
total 2017- not
naphthalene 2019 2 mg/L na detected 0.03 various
EPA 625
semi-volatile not
organics 2018 2 mg/L na detected various various
EPA 625.1
chlorinated not
pesticides 2018 2 mg/L na detected various various
EPA 608.3
total 2017- 3 mg/L na <0.05 ns ns
phenolics 2019
PCBs 2017-2019 3 mg/L na not detected 0.0005 0.0005
gross alpha 2018 1 Ci/L na 6.74 ns 15
gross beta 2018 1 Ci/L na 27.2 ns 50 b
radium-226 20018 2 pCi/L 0.169 0.527 5 5
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities _ 10 - DRAFT November 3, 2020
radium-228 2017 2 pCi/L 0.131 1.61
2018
pH 2016- 3 pH units 7.08 7.64 6 to 9 6.5 to 8.5 a
2018
several
2018- times a
BOD 2019 week mg/L 1.03 6.84 ns ns
during
3Q
once a
TSS 2018- week mg/L 0.70 3.20 ns ns
2019 during
3Q
several
fecal 2018- times aMPN/100 <500/100 mL
coliform 2019 during mL 1.00 130 e 5 percent
3Q
2018- daily
turbidity 2019 during NTU 0.24 1.32 ns d
3Q
NMED/DWB-NM Environment Dept/Drinking Water Bureau
a secondary drinking water standard(aesthetic-related,non-enforceable guideline)
b NMED/DWB-defined level below which the equivalent radiation is below EPA mandated radiation threshold
of 4 mrem/yr
standard is for total coliforms,including fecal coliform and E. Coli:No more than 5 percent samples total
coliform-positive in a month.
d-For systems that use conventional or direct filtration,at no time can turbidity> 1 NTU,and samples for
turbidity must be<0.3 NTU in at least 95 percent of the samples in any month. Systems that use filtration
other than the conventional or direct filtration must include turbidity at no time>5 NTU.
e general requirement for effluent discharge to a watercourse under 20.6.2.210LA NMAC
mg/L-milligrams per liter
pCi/L-picoCuries per liter
NTU-nephelometric turbidity units
MPN/100 mL—most probable number per 100 milliliters
ns—no standard
na—not applicable
bold indicate exceedance of standard
The EMWRF effluent appears to currently qualify as Class 1B under the rules of the
NMED/DWB. This class of reclaimed wastewater is approved for impoundments (recreational
or ornamental), irrigation of parks, school yards, or golf courses (with setback limitations),
irrigation of urban landscaping (with setback limitations), snow making, street cleaning, toilet
flushing, and backfill around non-potable piping.
Total dissolved solids (TDS)and chloride concentrations in the EMWRF have generally
exceeded NMED/DWB secondary drinking water standards,but these are aesthetic-related,non-
enforceable guidelines. It is unclear whether NMED may require that reclaimed water meet
groundwater discharge standards for TDS, sulfate, and other secondary standards for ASR
application.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 11 - DRAFT November 3, 2020
Nitrate concentrations have occasionally exceeded the NMED/DWB primary (health-
related) standard of 10 milligrams per liter(mg/L). However, of the 20 nitrate results reviewed,
only 4 exceeded the standard(and 2 of those results were 10.1 mg/L, slightly elevated above the
standard). Thus, for an ASR application, it may be possible to optimize the current water
treatment system to maintain nitrate results below the standard, or NMED may allow the City
to demonstrate that the average nitrate concentration of injected water would be below the
standard.
The primary issue for qualification as Class IA reclaimed wastewater(all uses) may be
the presence of fecal coliform in the effluent. The primary drinking water standard is for total
coliforms,including fecal coliform and E. Coli:No more than 5 percent of samples may be total
coliform-positive (TC-positive) in a month. Every sample that has total coliform must also be
analyzed for either fecal coliform or E. coli. A violation occurs if two consecutive TC-positive
samples occur, and one is also positive fecal coliform or E. coli. For an ASR application, it is
unknown whether NMED may allow for the presence of fecal coliform in water to be injected,
if the City can demonstrate that it would be absent in water that is recovered.
EMWRF—Aquifer Injection
The City water system chiefly draws groundwater from the Mesilla Basin through wells
in the Valley Well Field and the West Mesa Well Field, and from the Jornada del Muerto Basin
through wells in the East Mesa Well Field. The EMWRF is located just east of the horst that
represents the boundary between these two basins.
Inactive wells in the Valley Well Field were considered for suitability for use as ASR
wells to inject reclaimed water directly into the Mesilla Basin aquifer. Inactive wells under
consideration are generally in the Interstate-25 Corridor area within relatively close proximity
to the EMWRF, as well as Well 10 on the eastern edge of the Valley area. All well locations are
shown in Figures 1 and 4. Selection criteria relative to each well location's appropriateness for
ASR application are discussed below and summarized in Table 3 (listed numerically).
Preliminary groundwater modeling by JSAI in the Interstate-25 Corridor area has informed the
selection of sites with good potential for ASR application. Sites could be further prioritized
based on proximity to the City's recycled water(purple pipe) distribution system.
The condition of any production well which is considered for use as an ASR well should
be evaluated. We recommend a video survey as well as a casing integrity test. Depending upon
the condition of the well screen,rehabilitation may be required. In some cases,the existing well
may be at the end of its serviceable life, and a replacement well may be required for ASR
application.
• Well 10 (LRG-430) is relatively isolated from active supply wells in the Valley Well
Field. The site could be considered for injection and recovery, as no nearby recovery
wells exist. The nearest downgradient wells are located approximately 4,500 feet east-
southeast. These are the Paz Park Well and Well 18, which are used as sampling and
plume capture wells related to the Griggs and Walnut site. Furthermore, Well 10 was
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 12 - DRAFT November 3, 2020
drilled in 1951, and may not be reliable for use as an injection well. We do not
recommend existing Well 10 for use in an ASR program, but a replacement well could
be considered for injection and recovery.
• Well 19 (LRG-430-S-6) is used for groundwater monitoring and sampling related to the
Griggs and Walnut site, and is not available for ASR application.
• Well 20 (LRG-430-S-7) has been taken out of service due to effects on the Griggs and
Walnut site, and is not available for ASR application. However, additional groundwater
modeling could be used to determine if injecting water into Well 20 could be beneficial
to the Griggs and Walnut remediation effort.
• Well 21 (LRG-430-S-8)is located upgradient of the Griggs and Walnut site.No recovery
wells exist between Well 21 and the Griggs and Walnut PCE plume. If Well 21 is used
alone for injection and recovery, there is the possibility that injected water may be lost
to the cone of depression around the Griggs and Walnut site. Therefore, we do not
recommend Well 21 as an ASR injection well. If Well 54 is used as an injection well
(see below), Well 21 could function as a downgradient recovery well. Additional
groundwater modeling could determine if inclusion of Well 21 in an ASR program would
have deleterious effects on the Griggs and Walnut remediation effort. Well 21 appears
to have been completed in 1962 or 1964. The casing condition is unknown, and would
need to be evaluated.
• Well 23 (LRG-430-S-10) is located at the north end of the Valley Well Field. It is
approximately 2,000 feet north-northwest, and upgradient, of active Well 62. We judge
this to be a favorable site for ASR.A well in this location could be used for injection and
recovery, or as an injection well alone, with Well 62 serving as a recovery well.
However, Well 23 was completed in 1966. Based on a video survey conducted in 2016,
JSAI concluded that the screen is no longer open, and substantial portions of the casing
are missing. JSAI recommended that the well be plugged and abandoned, and a
replacement well be installed. Use of the Well 23 site in an ASR program would require
a replacement well to be drilled.
• Well 24 (LRG-430-S-11) is located south, and upgradient, of City Well 61. LCU ceased
municipal pumping of Well 61 in March, 2019 in order to minimize the potential for
vertical and southward movement of the Griggs and Walnut PCE plume. There are no
other active wells nearby which could serve as recovery wells.Nearby upgradient Wells
38 and 44 may be considered as injection wells.Additional groundwater modeling could
determine if using Well 24 as a recovery well would have harmful effects on the Griggs
and Walnut remediation project. However, we do not recommend using Well 24 as an
injection well in the ASR program.
• Well 26 (LRG-430-S-13) is used for groundwater chemistry sampling related to the
Griggs and Walnut site, and is not available for ASR application.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 13 - DRAFT November 3, 2020
• Well 38 (LRG-430-S-4) is located 2,200 feet east, and slightly upgradient, of Well 24.
Well 38 may be a good candidate for use as an injection and recovery well.
Downgradient Well 24 could additionally function as a recovery well, provided
groundwater modeling determines that pumping from Well 24 would not have harmful
effects on the Griggs and Walnut remediation project.
• Well 44 (LRG-430-S) is relatively isolated from active supply wells in the Valley Well
Field. Regional groundwater flow is to the southeast. Well 44 could be considered for
both injection and recovery. Active Wells 35 and 70 are located approximately 5,000
feet west-southwest, and downgradient. Additional groundwater modeling could
determine if these wells are near enough to serve as recovery wells.
• Well 54 (LRG-430-S-25) is located 3,000 feet north and upgradient of inactive Well 21,
and 2,500 feet southeast of active Well 28. Well 54 could be considered as an injection
well and recovery well, or as an injection well with Well 21 functioning as a recovery
well. This would be dependent upon groundwater modeling determining that inclusion
of Well 21 in an ASR program would not have deleterious effects on the Griggs and
Walnut remediation effort. Well 21 was completed in approximately 1962, and the
casing condition is unknown. Injected water that is not recovered from Well 21 would
flow southeast, and may be lost to the cone of depression formed around the Griggs and
Walnut Superfund site.
• Well 57 (LRG-430-S-31) is located 4,500 feet east of the Griggs and Walnut site, and
could be considered as an injection and recovery well. Regional groundwater flow is to
the southeast, though this may be affected by the cone of depression around the Griggs
and Walnut site. Additional groundwater modeling could determine if Well 57 would be
a feasible injection and recovery well. There is also potential that discharge of water into
upgradient Well 57 could benefit the Griggs and Walnut remediation effort. Nearby
Wells 19 and 20 have been taken out of service due to effects on the remediation site.
• Well 60 (LRG-430-S-35) sits near the interpreted divide between groundwater flow to
the southwest, toward active Well 32B, and to the northeast, toward the Griggs and
Walnut plume capture wells.The Well 60 site may be a good candidate for ASR injection
and recovery. Additional groundwater modeling could establish whether Well 32B,
2,000 feet southwest, could also function as a recovery well.
• Well 61 (LRG-430-S-37) is not in use. LCU ceased municipal pumping of Well 61 in
March, 2019 in order to minimize the potential for vertical and southward movement of
the Griggs and Walnut PCE plume. This site is not suitable for ASR application.
However,additional groundwater modeling could be used to determine if injecting water
into upgradient Well 61 could be beneficial to the Griggs and Walnut remediation effort.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 14 - DRAFT November 3, 2020
Table 3. Summary of inactive wells and potential for ASR application of EMWRF
effluent, City of Las Cruces,New Mexico.
sub- total screen casing depth to
well region year depth, interval(s), diameter, water,ft potential for ASR
number drilled ft ft in. bmp application (Y/N)
Well 10 Valley 1951 381 270 to 370 16/12 94.2 Y (replacement well)
I-25 348 to 363;
373 to 383;
Well 19 1962 612 393 to 460; 16/12/8 225.7 N
532 to 540;
564 to 604
1-25 380 to 395;
Well 20 1963 677 415 to 525; 16/12/8 236.6 N
615 to 673
Well 21 I-25 1962 632 366 to 620 16 235.3 Y (recovery only)
Well 23 I-25 1966 592 452 to 592 16/12/8 231.3 Y (replacement well)
Well 24 I-25 1966 591 381 to 591 16/12/8 206.1 Y (recovery only)
Well 26 1-25 1969 700 410 to 510; 16/12 176.5 N
600 to 700
Well 37 WM 1982 640 440 to 640 12 320 Y
Well 38 1-25 1984 780 320 to 400; 16/10 266.0 Y
480 to 780
Well 44 I-25 1987 620 400 to 600 16 161.1 Y
Well 54 I-25 1972 480 272 to 480 12 269.6 Y
Well 57 I-25 1990 532 408 to 516 12 292.9 Y
Well 60 I-25 1994 700 350 to 690 16/12 104.8 Y
Well 61 1-25 1995 1,070 610050 0 to 16/12 205.2 N
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 15 - DRAFT November 3, 2020
LRG- EM 1964 550 nd 8 350 Y(recovery only)
5039
LRG- EM 1969 550 nd 8 nd Y (recovery only)
5039-S
LRG- EM 1990 600 350 to 600 12 333 Y
5039-S-2
I-25—Interstate-25 Corridor area in the Mesilla Basin
WM—West Mesa area in the Mesilla Basin
EM—East Mesa area in the Jornada del Muerto Basin
nd—no data
Reclaimed wastewater from the EMWRF could also be injected in the Jornada del
Muerto Basin aquifer. The East Mesa Well Field produces groundwater from the Jornada del
Muerto Basin, which is only shallowly connected to the Mesilla Basin. Depth to water in the
area of the East Mesa Well Field is approximately 400 to 600 ft bgl. Wells in the East Mesa
Well Field have shown non-pumping water-level decline of 3 to 6 feet per year. Addition of
reclaimed wastewater would help to offset this decline.
Inactive wells in the East Mesa Well Field were considered for suitability for use as ASR
wells to inject reclaimed water directly into the Jornada del Muerto aquifer. Three inactive wells
are located in the southwest area of the East Mesa Well Field. Well LRG-5039-S-2 was built in
1990 and may represent good potential for aquifer injection and recovery. There are two
downgradient wells: Well LRG-5039-S (built in 1969) and Well LRG-5039 (built in 1964). If
these wells are determined to be in sufficiently good condition, one or both could function as a
recovery well. However, these wells are located at the west, and downgradient side, of the East
Mesa Well Field. Water injection at this location would not likely offset the water-level decline
observed in the rest of the well field. Depending on water system requirements, a well in the
northeast side of the well field may be more beneficially converted to an ASR injection and
recovery well.
EMWRF—Vadose Zone Infiltration
The use of vadose zone infiltration basins is a low-cost,low-maintenance mechanism to
return reclaimed wastewater to the aquifer. Basins could be constructed to utilize existing
topography for impoundment; such as adjacent to the earth dam in the Interstate-25 corridor,
where the depth to water ranges from approximately 100 to 300 ft bgl. Infiltration basins can
also be constructed as water features in parks.Large parcels of undeveloped property are present
around Well 54 and Well 57 which could be used for infiltration basins.These could additionally
be constructed as water features in park land.
If a vadose zone infiltration basin method is selected,we recommend an infiltration study
be conducted at the proposed site in order to determine the land surface area required for the
desired volume and rate. Proposed sites could be evaluated with a series of auger boreholes
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 16 - DRAFT November 3, 2020
drilled to approximately 50 or 100 ft bgl. These boreholes would be used to collect samples to
determine the characteristics and thickness of near-surface lithologic units as well as to perform
constant-head infiltration tests to assess potential infiltration rates. In the lower Valley area, it
may be possible to assess both saturated and unsaturated infiltration rates.
At any site selected for infiltration basin(s), it must be demonstrated that the water
applied to the basins will reach the water table soon enough to provide a demonstrable offset to
drawdown due to pumping from recovery/supply wells. At sites where the depth to water is too
shallow, the ability of the saturated sediments to accept water infiltration will limit the amount
which may be stored, with an increased possibility that water may be lost to the river or other
surface systems,or may become contaminated from other shallow sources (e.g. dry cleaners and
underground fuel storage tanks). During periods of above-average precipitation, stored water
could mound upward and cause discharge at the surface. Infiltration basins situated higher above
the water table may be feasible, but may present regulatory difficulty in demonstrating that the
water will reenter the aquifer, providing recharge, and be accessible for later recovery.
The depth to water west of the EMWRF (west of the horst, in the Mesilla Basin) is on
the order of 375 to 400 ft bgl. There are no production wells in this area to recover stored water.
In order to employ an infiltration basin west of the EMWRF, a recovery well would have to be
built.
The depth to water in the East Mesa Well Field is between approximately 400 and 600
ft bgl. An infiltration basin nearby the pumping wells could help offset the large water-level
decline (3 to 6 feet per year). It would be critical to establish that the water is reentering the
aquifer and being recovered, in order to successfully permit an ASR program.
Farther to the west, in the Valley area, the depth to water averages approximately 50 ft
bgl. An infiltration area could be selected up-gradient and adjacent to the City's pumping wells
in the Valley Well Field. In some areas, the shallow depth to water could limit the potential
infiltration rate, and care would have to be taken to avoid loss of water to the Rio Grande. This
would also require a longer pipeline, as the Valley Well Field is approximately 5 miles from the
EMWRF. We recommend unsaturated and saturated hydraulic conductivity testing, conducted
in a series of auger holes,be combined with groundwater flow modeling to establish the viability
of an injection site in the Valley area. Environmental site assessments should be conducted at
any proposed sites to avoid risk from any preexisting shallow environmental contamination,
such as gas stations/storage tanks, dry cleaners, etc.
Potential Influence on Griggs and Walnut PCE Plume
Additional groundwater modeling would be beneficial to ensure that any ASR
application of treated effluent in the Interstate-25 Corridor area does not have a deleterious effect
on the Griggs and Walnut PCE plume remediation project. Alternatively, treated effluent from
the EMWRF might be applied to assist remediation by helping to control and move the PCE
plume toward the capture wells (Well 18 and Well 27).
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 17 - DRAFT November 3, 2020
Prior to the Wells 54 and 57 being taken out of service, the Griggs and Walnut PCE
plume had migrated northeastward under the influence of pumping the two wells. Since these
wells have been inactive, groundwater flow direction in the area has reverted to the southwest,
toward the cone of depression formed around capture Wells 18 and 27. Upgradient addition of
EMWRF effluent water, either by direct injection or infiltration, may assist in the remediation
process. Water added at the Well 54 and Well 57 sites could move the plume in the direction of
the capture wells. The large parcels of undeveloped property around each of these well sites
could be used for infiltration of effluent water from the surface. The depth to water measured in
2020 in Well 54 is 268 ft bgl, and in Well 57 it is 290 ft bgl. Wells 20 and 61,which were taken
out of service due to effects on the PCE plume, may also be suitable sites to inject reclaimed
wastewater up-gradient of the plume. Another option would be to attempt to influence the PCE
plume by injecting water at a low rate into a series of purpose-built small-diameter wells
surrounding the plume.
Direct injection into the wells would require effluent water to be treated to drinking water
standards. Infiltration from the surface would require less water treatment. However, with
infiltration from the surface, there is the potential for other contamination present in the
sediments above the water table to migrate into the aquifer. This risk could be assessed by
conducting an environmental site assessment possibly coupled with a soil boring program at any
proposed infiltration site.Additional groundwater modeling could be used to determine the most
effective option.
West Mesa Wastewater Treatment Plant—Aquifer Injection
There are fewer wells to be considered for ASR application in the West Mesa Well Field
than in the Valley Well Field. With the groundwater flow direction being generally southeast,
an injection site would best be located in the northwestern part of the West Mesa Well Field to
allow for recovery of stored water from pumping wells located downgradient, and avoid loss to
the Rio Grande.
Well 37 is located on the West Mesa, approximately 1,800 feet south of the intersection
of Interstate 10 and US Highway 70. The well is located west-to northwest of producing Wells
36, 46, and 63, making it upgradient or across-gradient. Well 37 may be a good candidate for
ASR injection and recovery,with Wells 36,46, and 63 functioning as additional recovery wells.
West Mesa Wastewater Treatment Plant—Vadose Zone Infiltration
Depth to water in the area of the West Mesa Well Field averages approximately 300 ft
bgl. General groundwater flow direction is to the southeast. An infiltration basin could be
constructed near to, and upgradient of, the cluster of 3 active City wells: Wells 36, 46, and 63.
The City has permits for a number of West Mesa wells which have not yet been drilled. These
planned wells could also be used for recovery of stored water.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 18 - DRAFT November 3, 2020
Other ASR Projects In New Mexico
Albuquerque—Bear Canyon Recharge Project
• Water source: reclaimed wastewater blended with disinfected river water
• Treatment standard: discharge standards
• Water discharge method: infiltration basins
• Water recovery method: existing municipal wells
• Depth to water: 250 to 400 ft bgl
• Volume stored: 4,500 AFY
Albuquerque—Large Scale Recharge Project
• Water source: reclaimed wastewater
• Treatment standard: drinking water standards plus dechlorination
• Water discharge method: dry well(vadose zone)& direct injection via purpose-built well
• Water recovery method: existing municipal wells &pumping from injection well
• Depth to water: 150 ft bgl
• Volume stored: 5,000 AFY
Rio Rancho
• Water source: reclaimed wastewater
• Treatment standard: drinking water standards
• Water discharge method: direct injection via purpose-built well
• Water recovery method: existing municipal wells
• Depth to water: 800 ft bgl
• Volume stored: 1,000 AFY
Ruidoso (pilot study in progress)
• Water source: reclaimed wastewater and treated surface water
• Treatment standard: drinking water standards
• Water discharge method: existing municipal well
• Water recovery method: pump from injection well
• Depth to water: 100 ft bgl
• Volume stored: (to be determined in pilot study)
Discussion
As identified in the City's 40-Year Water Development Plan (2017), ASR is a potential
way for the City to make use of reclaimed wastewater for alternate supply. Additionally,
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities _ 19 - DRAFT November 3, 2020
reclaimed wastewater may be used to offset regional water-level declines in the Mesilla and
Jornada del Muerto Basins. Numerous locations exist within the City that have the potential for
good ASR performance via injection through wells, or infiltration through vadose zone
infiltration basins.
Direct aquifer injection through existing or purpose-built wells can be used to efficiently
mitigate water-level drawdown. Additionally, it may be easier to demonstrate successful
recovery of stored water to the NMOSE when using direct aquifer injection together with nearby
recovery wells. However, regulations require any water injected into the aquifer to be treated to
drinking water standards. Some of the existing inactive wells should not be considered, due to
well age or condition, and potential impact on the Griggs and Walnut Superfund site.
Infiltration using vadose zone infiltration basins represents a lower-cost and lower-
maintenance option than direct injection. Furthermore, the NMOSE requires water discharged
at the surface, such as into a settling basin, to be treated to the less-stringent groundwater
discharge standards. Table 4 contains a comparison of New Mexico groundwater discharge and
drinking water standards. However, it may be more difficult to prove successful entry of this
water into the aquifer and subsequent recovery of stored water to the NMOSE.
Site-specific studies will be crucial for the proposed reclaimed wastewater ASR project,
in order to (1) determine whether the water can be successfully returned to the water table and
recovered for later use, considering both physical return of the water and NMOSE accounting,
and (2) determine whether the proposed water treatment and aquifer-return approach is
protective of environmental and human health standards. These studies may include:
• Borehole infiltration testing should be conducted to assess potential infiltration rates at
potential sites for vadose zone infiltration basins.
• Groundwater flow modeling could be used to assess the ability of the Mesilla Basin
aquifer to store injected water, and to evaluate potential loss to the Rio Grande. It can be
determined whether wastewater applied in infiltration basins, rather than through
injection wells,would reach the water table soon enough to provide a meaningful offset
to drawdown due to pumping from supply wells. Then a conventional return-flow plan
associated with the existing permits may be acceptable to the NMOSE and NMED.
• A constant-rate pumping test should be performed in each selected injection well in order
to assess the hydraulic properties of the aquifer, and a step-drawdown test should be
carried out for evaluation of well efficiency. Then, water from the proposed source
should be injected into the well during a 14-day period, followed by 14 days of recovery
pumping. A long-term pumping test should be performed subsequent to the injection
test to compare the pre- and post-injection hydraulic properties of the aquifer. The
physical condition of any selected well would need to be evaluated prior to testing.
• Water-quality data for the effluent from the West Mesa Water Treatment Plant and
EMWRF should be reviewed and included in discussions with the NMOSE and NMED.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 20 - DRAFT November 3, 2020
• A geochemical mixing model should be constructed to assess compatibility and
determine if introducing reclaimed water to the shallow groundwater would negatively
impact the aquifer with respect to the development of mineral precipitation that would
result in irreversible hardness, or plugging of the well or aquifer.
Table 4. Comparison of New Mexico groundwater discharge and drinking water
standards
groundwater
parameter units discharge drinking water
standard
standard
TDS m /L 1,000 5001
chloride m /L 250 2501
sulfate m /L 600 2501
nitrate as N m /L 10 10
ammonia m /L ns ns
TKN m /L ns ns
fluoride m /L 1.6 4
aluminum m /L 5 0.05 to 0.201
antimony m /L 0.006 0.006
arsenic m /L 0.01 0.010
barium m /L 2 2
beryllium m /L 0.004 0.004
cadmium m /L 0.01 0.005
chromium m /L 0.05 0.1
cobalt m /L 0.05 ns
copper m /L 1 1.3
iron m /L 1 0.31
lead m /L 0.015 0.015
manganese m /L 0.2 0.051
mercury m /L 0.002 0.002
molybdenum m /L 1 ns
nickel m /L 0.2 ns
silver m /L 0.05 0.11
thallium m /L 0.002 0.002
uranium (total) m /L 0.03 0.03
zinc m /L 10 5.01
boron m /L 0.75 ns
selenium m /L 0.05 0.05
cyanide m /L 0.2 0.2
volatile organics low-level EPA 624 mg/L various various
Low
total naphthalene EPA 625 m /L 0.03 various
semi-volatile organics EPA 625.1 m /L various various
chlorinated pesticides EPA 608.3 m /L various various
PCBs I m /L 1 0.0005 1 0.0005
JOHN SHOMAKER & ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 21 - DRAFT November 3, 2020
gross alpha Ci/L ns 15
gross beta Ci/L ns 50 b
radium-226 Ci/L 5 5
radium-228 Ci/L
H pH units 6 to 9 6.5 to 8.5 a
fecal coliform MPN/100 mL <500/100 mLe 5 percent
turbidity NTU ns d
a secondary drinking water standard(aesthetic-related,non-enforceable guideline)
b NMED/DWB-defined level below which the equivalent radiation is below EPA mandated radiation threshold
of 4 mrem/yr
standard is for total coliforms,including fecal coliform and E. Coli:No more than 5 percent samples total
coliform-positive in a month.
d-For systems that use conventional or direct filtration,at no time can turbidity> 1 NTU,and samples for
turbidity must be<0.3 NTU in at least 95 percent of the samples in any month. Systems that use filtration
other than the conventional or direct filtration must include turbidity at no time>5 NTU.
e general requirement for effluent discharge to a watercourse under 20.6.2.210LA NMAC
mg/L-milligrams per liter
pCi/L-picoCuries per liter
NTU-nephelometric turbidity units
MPN/100 mL—most probable number per 100 milliliters
ns—no standard
JSAI is meeting with the NMED and NMOSE to discuss potential approaches and
locations for ASR application of the City's reclaimed wastewater. These early discussions
include conversations on such topics as:
• Discharge of water via infiltration basins vs. wells (direct aquifer injection)
• The role of depth to water, especially with regard to infiltration basins
• Discharge water quality standards
• Discharge/storage in the Mesilla vs. Jornada del Muerto Basins
• Discharge water potentially interacting with the Griggs and Walnut Superfund Site(PCE
plume)
• Interpretation of the water rights Burden of Proof rules
• Required geochemical/mixing modeling
The results of these discussions should provide the City with guidance as to which
potential approaches and locations may be most easily permitted, and any approaches that the
NMOSE and NMED may reject out of hand. Following these preliminary meetings with
NMOSE and NMED, the City may be in the position to perform additional, more detailed
studies, such as evaluating more advanced water treatment and area-specific groundwater
modeling.
Establishing and permitting an ASR program in the current regulatory environment is a
relatively long and expensive process. For example, the Albuquerque Bear Canyon Recharge
Project was finally established after 5 to 7 years of study. It may be preferrable for the City to
apply for return flow credit. This process requires a return flow plan, but does not require
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 22 - DRAFT November 3, 2020
demonstrated recoverability, as in an ASR plan. If the reclaimed wastewater is discharged to
infiltration basins,this would not require treatment to drinking water standards. This reclaimed
water could be discharged east of the EMWRF into the Jornada del Muerto basin in order to
offset regional water-level decline. The conditions and process to apply for a return flow credit
are set out in NMAC 19.26.2.11.
Some water systems in New Mexico and elsewhere in the U.S. have explored direct
potable reuse (DPR) of treated wastewater. At present, this represents a large — potentially
insuperable — permitting obstacle. The Village of Cloudcroft, New Mexico permitted a DPR
project in response to very limited water sources for the seasonal tourist population. However,
the Village has not yet completed a discharge plan and permit for disposal of the small portion
of un-treatable residual water, so the DPR system is not yet active. Disposal of the residual
waste that results from a DPR project represents a unique permitting challenge.
Public acceptance of DPR represents an additional obstacle. ASR has also faced public
opposition in the past, but is now becoming more accepted. There is the potential that the
reclaimed wastewater stream which may be returned to the aquifer via ASR or return flow plan
in the near future may one day be exploited for DPR. At the present, however, direct reuse
appears to be less feasible than ASR due to difficulty of permitting,water treatment, disposal of
residual waste,negative public opinion, and high associated costs.
APF:of
Enclosures
Figure I Aerial photograph showing locations of City of Las Cruces supply wells and
landfill monitoring wells, and City of Las Cruces observation wells, used for
water-level monitoring program
Figure 2 Geologic map of the northern part of the Mesilla Basin and southern part of the
Jornada del Muerto Basin showing the City of Las Cruces area and selected
existing City of Las Cruces wells, Las Cruces Utilities, Dona Ana County,New
Mexico.
Figure 3 Southwest-to-northeast hydrogeologic cross-section A-A' of the City of Las
Cruces Area
Figure 4. Aerial photograph showing December 2019 water-level elevation contours, City
of Las Cruces,New Mexico.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
Las Cruces Utilities - 23 - DRAFT November 3, 2020
References
Finch, S. T., Jr., 1999, Results from installation of ground-water monitoring system, and
proposed ground water monitoring plan, Las Cruces Landfill, Las Cruces, New Mexico:
Consultant's report prepared by John Shomaker& Associates, Inc. for the City of Las Cruces,
25 p.
Frenzel, P. F., and Kaehler, C. A., 1990, Geohydrology and simulation of ground-water flow in
the Mesilla Basin,Dona Ana County,New Mexico, and El Paso County,Texas: U.S. Geological
Survey Open File Report 88-305, 179 p.
Hawley, J. W., and Lozinsky, R. P., 1992, Hydrogeologic framework of the Mesilla Basin in
New Mexico and western Texas: New Mexico Bureau of Mines and Mineral Resources, Open-
File Report 323.
[JSAI] John Shomaker & Associates, Inc., 2002, Aquifer Storage and Recovery Assessment,
Mesilla and Jornada Basins,Dona Ana County,New Mexico:report prepared by John Shomaker
& Associates, Inc.,for City of Las Cruces and Lower Rio Grande Water Users Organization, 36
p. plus figures and appendices.
[JSAI] John Shomaker& Associates, Inc., 2017, Well report for replacement Well 3 1 B (LRG-
430-POD58), City of Las Cruces, New Mexico: well report prepared by John Shomaker &
Associates, Inc., for Las Cruces Utilities, 18 p. plus figures and appendices.
[LAMED] January, 2007. Ground Water Quality Bureau Guidance: Above Ground Use of
Reclaimed Domestic Wastewater. January 2007
[NMISC] New Mexico Interstate Stream Commission, 2018, New Mexico State Water Plan,
Part L Policies, prepared by NMISC, and adopted by NMISC on December 6, 2018, 53 p. plus
appendix.
Shomaker, J.W., and Finch, S.T., Jr., 1996, Multilayer ground-water flow model of southern
Jornada del Muerto Basin, Dona Ana County, New Mexico, and predicted effects of pumping
wells LRG-430-S-29 and —S-30: Albuquerque, New Mexico, John Shomaker & Associates,
Inc., 26 p., 5 tables, 20 figures.
Woodward, D.G. and Myers, R.G., 1997, Seismic investigation of the buried horst between the
Jornada del Muerto and Mesilla ground-water basins near Las Cruces, Dona Ana County,New
Mexico: U.S. Geological Survey Water Resources Investigations Report 97-4147, 45 p.
JOHN SHOMAKER& ASSOCIATES, INC.
WATER-RESOURCE AND ENVIRONMENTAL CONSULTANTS
pxw-sua�ex�Tiuiioy uow�a'vA�-ia�eM�sa�n�sa1�W�N:�
z
� W
!� W
Al
X o�j
Wcu w
ti
m
v
U
v O
e� o� (�❑ - ry n M N +�
N bD
} 02
431
J � O
ti
N �
N N
CQ
� O M
CQ
N � d
N
+� Q
1 0 3
CQ
w
75
Gy
Nis
4W
nnaa
' N A
d C
v O C
U �a
J C
N
Y
U N
(O O Y
U
O U O U
N N C Y Y
O N N U U
(6 N U ?i N 'E O O
3 2 w Y O
N
O O w U y U Y C O C N N Y
.i 3 y O C +• O C C O Q .V N p W
N y 7 O > O O O (6 N r > Q
o w E m (7 w m m E m -a m
C iy j O N w " N O p N O N C O U
Q N N C 7 O N y U U N '6 -O O N C C N N (6 U O
X m U N 3 — N N N N — 7 C N Q 3 N O N 7 7 d
W J N i O N Q Q fn N to D- N N Q = d fn fn fn d
Q
o U Q
Ucn
cu n 0 0 0 'a F F F F F d d � � � OU OU >
•y� -� C�j o
pxwueld-j,�-pp\ueldiR-p6\sa3rup sel\OVOb1:0
CO z x
(n 2 O
m U
m
Q
H
CA
Q 0
r - .°� O
• a t U 2 Cd ti
U H ♦ m v I�
0
H C1 U) U
U CL
CL
U O U
♦ j CA
p a ♦♦ C O.
♦ N
® ` ♦♦ - w N
♦ s
N o CA
o � ♦♦ L "O U
CA
CA
CL
�� ♦
U bA
♦ . ,.�. �'1 O o N
Ir
� � J
� � N
N L�
O V
L O �
C 0 C�j
m Cli
CL
® I
CA
a I ♦ O 4.
a Q ♦ Un
I I.. I �♦ "' N U
a�
I %, I
U U) m ,
N
N
(J
0
lbq `Aapen aq;ui banal punoa6 nnolaq q;dap
0 0
0 0 0 0 0 0
., Wa o 0 0 0 o N U O N � co co
O
O
� W
� o
M
0
\2- �LLU) O
M x
L �
o
- a, o o o
L
E D 70 M
U C�. a
o y E c 4
a� aNi m aNi O
F CO
N N
N
N
O
® N
J O
O
O
C)
V L N J
Q— I
N > > E I O
>— E V I U
(Q 4-- >_ (0 �. f0
O
.N L E p I O
U apuea0 Q/& -- --J o
Q O_ L O
=3D L 0
'C
O o m a)
Q N N J N
Q LL �_ LL cz
cu (B
U) U O
I
O
N
� O
M
zs
bIJ
� w
laodaiy soonao sel
Q ,
o 0 0
(n o 0 0 0
C C C 9-
LO v Iswe 4 `uoi;ena19 Cl) `V
z pxw 6uiioy uow�a'vA�-ia,eM�sa�n�saIYUYJN�
L
L U
O U Z
O N.�-• G�
o ° 3 m `o
3 o a —
a m �L O
Q O m a
a LU d d > CO °
a 'i C9 Eo ° )
U m U) 5 CG
o a m
44
� N
� bio 0
I O
I
k�y`+e! ��'�' �s.};p- ��f(5�•�t �.,f}1��T.','�:v �XT�j.�yf i :� �� o
l YS\ T
I J M J
ID
Jli
�Y
J M N Y n J O N
U
U
U M M U M
N N U
� M
U M U M U U J
U M
m r U Yjf
N �UuY"Y U
O
N U M d M J M U M U
uN �bgF a� c' tui o
U M
� � O
U O M
JM J UM O�BIf O
0 U� C
J M U M N
O U i >
YiFt' l
It
.. • ( U%M C N
S8£ U V N
M
M
`
J W A
U M a�-y�`. U n in O o98E U U U
bA
U m
M �
V > - i•`
h +
U
M
L,
1 N�
4A; J