Drinking Water Quality Improvements
For the Pomerene Domestic Water Improvement District,
Pomerene, Arizona
October 31, 2014
U.S. Environmental Protection Agency | Region 9
75 Hawthorne Street
San Francisco, CA 94105
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Pomerene Domestic Water Improvement District
Drinking Water Quality Improvements
Environmental Assessment
1.0 INTRODUCTION
The United States Environmental Protection Agency (EPA) administers the Border Environment
Infrastructure Fund (BEIF), which provides grant funding for water and wastewater infrastructure
projects located within 62 miles (mi) (100 kilometers [km]) of the international boundary between
the United States (U.S.) and Mexico.
EPA policy for use of BEIF funds requires planning and design and certification of projects by the
joint Border Environment Cooperation Commission (BECC)-North American Development Bank
(NADB) Board as a condition for receiving a BEIF award for construction. The EPA requires that
a proposed project comply with the National Environmental Policy Act (NEPA) before BEIF funds
can be authorized.
In accordance with the U.S. Council of Environmental Quality (CEQ) regulations, 40 CFR Parts
1500-1508, and EPA regulations (40 CFR Part 6) as guidance, this EA documents the environmental
consequences in the U.S. of the proposed federal action. The purpose of this document is to comply
with NEPA documentation requirements for the proposed federal action under consideration, which
consists of the Drinking Water Quality Improvements for the Pomerene Domestic Water
Improvement District (PDWID) in Pomerene, Arizona. This EA incorporates by reference the
September 2014 Environmental Information Document for PDWID's Drinking Water Quality
Improvements project.
1.1 STUDY LOCATION
PDWID provides water service for approximately 370 connections within the unincorporated
community of Pomerene in Cochise County, Arizona Below is Figure 1 - Vicinity Map - depicting
the PDWID water service area. Pomerene is located approximately two miles north of Benson,
Arizona.
The footprint for disturbance for all seven action alternatives is referred to collectively herein as the
"project area". The project area encompasses potential construction impacts that could occur during
implementation of any of the project alternatives, although only the preferred alternative, Alternative
6, will be carried forward. A map depicting the existing water system facilities is provided in
Figure 2.
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Pomerene Domestic Water Improvement District
Drinking Water Quality Improvements
Environmental Assessment
TUCSON
Approximate Scale 11nch * 10 Mises
Water Improvement
District Boundary
PROJECT
LOCATION
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• mi \
tm>4 \
1 \
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ARIZONA
PROJECT VICINITY
viemtty Map
Rguw 1
T16S.R20E Portion of Sections 27, 23,3-3, 34 & 35,
T17S.R20E Portion of Sections 2.3. & 11
Cochne County Arizona
Image Soiree: ArcCtS Online USA H>po Map
POMERENE DOMESTIC WATER
IMPROVEMENT DISTRICT
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Pomerene Domestic Water Improvement District
Drinking Water Quality Improvements
Environmental Assessment
Wfil No. 4
Flow 120 flpm
Ar?«nlc 22 7 ppb
Fluoride 0 4 mg/l
Well Ho 2
Row 100 gprn
Arsenic 10 8 ppb
Fluoride 3 4 mQlL
VMII NO 3
Flow 60 gpm
Arsenic 22 3 ppO
Fluoride 0 4 mgli.
:Di>mor>db»c> R<
Aiewfai
Westiand Resources, Inc
ExilUng Water Syjlwti Fac*»«s
Figure 2
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Wtll No S
{Out of Operation)
Flow 160 flpm
Arsenic 22 5 ppb
Fluorde 0.6 malL
Storage Tanks 1*2
{630.000 Gallons Total)
ivwil No. 1
Not For Potable
Uae
W»ll No 6
Proposed Flow 1T6 flpm
Arsenic 7X) ppb
Fluonde 3 8 mg/L
Legend
# Existing WHI
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———— Existing 2 hch Vttflar Man
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E*tiling 6 hr h V\W«r Man
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i I ty of Bonbon
City of Benson 6
Fire Flow Connection
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716S. R20E, Portion orSedttns 27.28. 33,3-1 & 35
T17$, R20E. PorliOT of Suctorn J, S, « 11
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Gafceta Fist East S Bsnsor- -JSOS 1i' CiuMrano*
POMERENE DOMESTIC WATER
IMPROVEMENT DISTRICT
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Pomerene Domestic Water Improvement District
Drinking Water Quality Improvements
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1.2 PURPOSE AND NEED
The purpose and need for water quality improvements to the PDWID system relate mainly to
consistently and reliably achieving long-term compliance with arsenic and fluoride drinking water
quality standards. Since 2009, PDWID has installed and operated arsenic treatment systems at
existing wells in an effort to meet the new standard for arsenic in drinking water at 10 parts per
billion (ppb), pursuant to EPA's Arsenic and Clarifications to Compliance and New Source
Contaminants Monitoring Final Rule published in the Federal Register on January 22, 2001 (66 FR
6976), and under Arizona Department of Environmental Quality (ADEQ)'s delegated authority to
enforce this rule.
The history of arsenic compliance in Pomerene indicates certain instances of arsenic primary
maximum contaminant level (MCL) standard violations. In addition, no treatment or systematic
blending is currently implemented for fluoride. Historically, fluoride has been "incidentally"
blended in the storage tanks with water from the other wells delivered via the distribution system.
This is not an effective blending and compliance strategy, due to the possibility of exceeding
secondary MCL fluoride levels if well sources with high fluoride concentrations are in operation
for an extended period of time. Given the historic water quality challenges in this system, drinking
water quality compliance is a key concern for the PDWID system. All existing wells comprising
the PDWID system, except one (Well No. 6), currently exceed the arsenic maximum containment
level (MCL) and two wells (Well Nos. 2 and 6) exceed the fluoride secondary MCL and are above
80% of the primary fluoride MCL. Well No. 6 is a new well drilled by PDWID. It would be
developed as a water supply well and connected to the PDWID water system as part of the
proposed project.
1.3 SCOPE OF ANALYSIS
The scope of this EA includes the evaluation of the impact to the relevant environmental resources
within the defined area of concern in the U.S. As defined in the CEQ regulations (§1508.25), the
scope consists of the range of actions, alternatives, and impacts to be considered in a NEPA-
compliant document.
2.0 PROJECT DESCRIPTION AND ALTERNATIVES
In accordance with CEQ regulations (§1502.14), this section of the EA: 1) presents and objectively
evaluates seven alternatives, including the No Action alternative; 2) presents EPA's detailed
evaluation of each alternative, so the reviewers may evaluate comparative merits; and 3) includes
appropriate mitigation measures.
2.1 PROPOSED ACTION
The proposed project entails design and construction of new infrastructure and changes to
operational treatment and controls to address compliance with federal and state arsenic and fluoride
drinking water quality standards. There are six action alternatives being considered in addition to a
"No Action" alternative. The Action Alternatives have been identified to ensure the water system's
long term compliance with arsenic and fluoride drinking water standards (both secondary and
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primary MCLs for fluoride). Preferred Alternative 6 - Deliver and Blend Well Numbers 2, 3, 4 and
6 at the Storage Tank - is identified as the preferred alternative for the project.
Preferred Alternative 6, includes transmission pipeline alignments from Well 6 to Well 2 after
treatment along the southeast boundary of the Pomerene Domestic Water Improvement District as
well as an alternate alignment along public road rights of way. Similarly, transmission pipelines
to combine Well Nos. 3 and 4 and convey them to the storage tanks have a preferred route along
private easements and alternate alignments along public road rights-of-way.
2.2 EXISTING WATER DISTRIBUTION SYSTEM
PDWID owns and operates a drinking water system to provide for domestic use and fire protection
for the residents of the community of Pomerene. The community of Pomerene has been actively
pursuing water system improvements for many years. The original water association was formed
in 1950 following the installation of Well No. 1 in 1948. Since then the district has added four
more well sites, storage capacity, distribution mains, and finally arsenic adsorption treatment
systems in 2009. In 2003, the association was converted to a domestic water improvement district
to enable the community to have more control over decisions regarding the water system, without
the processes requiring approvals through the Arizona Corporation Commission (ACC). In
addition, to the distribution lines, PDWID maintains drinking water infrastructure as described
below:
Storage Tanks
PDWID has a total of 530,000 gallons of water storage available in 250,000-gallon and 280,000-
gallon storage tanks. PDWID's first water storage tank was installed in 1977, followed by a
second, parallel tank at the same site installed in 2006. The tanks "float" on the water system,
meaning that they sit at a higher elevation than the water system and provide pressure by gravity
due to the elevation difference between the water level in the tank (the highwater elevation) and
the elevation of the water services. Storage tanks are filled by Well No. 2 (direct transmission
from Well No. 2 to the storage tanks) and from the distribution system with water delivered from
Well No. 3 and 4. Excess water that is not consumed by the residents fills the storage tanks from
the distribution system for use at a later time.
The two tanks have separate inlet/outlets which allow the tanks to float the system, and also allow
the tanks to fill from the system. The storage tanks are situated on a hill centrally located within
the PDWID service area. The hill is located at an approximate elevation of 3,620 feet above mean
sea level, and the 28-foot-tall tanks result in an approximate tank highwater elevation of 3,646 ft.
The base of the hill is at an approximate elevation of 3,550 feet and ground surface elevations tend
to decrease towards the west and closer to the San Pedro River.
The tanks include water level probes and a control system with radio telemetry that allows the
level in the storage tanks to control the operation of the wells in the water system that fill the tank.
The control system was installed in 1998. The control system provides for automatic rotation of
the wells in the start cycle, but does not provide PDWID with the ability to control or modify
which wells operate or to control the wells remotely.
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Groundwater Wells
PDWID owns and operates three domestic water supply wells (Well Nos. 2, 3, and 4), one
irrigation well that was once used for domestic supply (Well No. 1), and one well (Well No. 5)
that was previously used for domestic supply and is now disconnected from the distribution
system. Well No. 2 pumps through a 6-inch transmission main directly to the storage tanks. Well
Nos. 3 and 4 pump directly into the distribution system, and fill the tank indirectly (i.e., if the total
volume of water pumping from Well Nos. 3 and 4 at any given time is greater than the demand in
the water system, the excess water will fill the tanks). As such, the Entry Point to the Distribution
System (EPDS) location for Well No. 2 is at the outlet of the storage tanks, while the EPDS for
the other Wells 3 and 4 are located at each well after the arsenic treatment and prior to leaving the
well site and entering the water system.
In pursuit of finding low-arsenic water that would meet compliance without treatment, PDWID
passed a resolution to drill a new well in the east portion of the service area (farther east of Well
No. 2 which has the lowest arsenic levels). This well was drilled using PDWID funds in July 2013.
Water quality samples were collected during well drilling. Subsequently, PDWID has been
working with BECC and stakeholders to perform pump testing and water quality testing as part of
the alternatives evaluation. The capacities and arsenic and fluoride concentration levels for the
wells are listed in Figure 2, Existing Water System Facilities.
Arsenic Treatment
Wells Nos. 2, 3 and 4 have arsenic treatment installed and housed at each well site. The arsenic
treatment systems consist of fiberglass reinforced plastic (FRP) vessels equipped with Siemens
granular ferric hydroxide (GFH) adsorption media. Well No. 2 has one 48-inch diameter vessel
that treats 100 gpm. Well No. 3 has one 42-inch vessel that treat 80 gpm. Well No. 4 has one 36-
inch vessel and one 48-inch vessel installed in parallel configuration that treat 120 gpm.
The existing treatment systems at Well Nos. 2, 3, and 4 utilize a parallel, split-stream treatment
configuration. Under this treatment configuration, a portion of the well flow is bypassed
(untreated) and blended with treated water from the treatment system. However, as the treated
arsenic levels increase and start to break through the media, bypass flows are reduced considerably
to ensure proper blending for an acceptable arsenic level. Further, as the media reaches its capacity,
it becomes essential to treat the entire well flow.
None of existing wells is equipped with two FRP treatment vessels installed in series (water flows
through the first vessel and then through the second vessel) which would allow treatment vessels
to be operated in a lead/lag configuration, as opposed to single-vessel or parallel configuration
operation. The lead/lag alternate treatment configuration is being proposed as part of the project
improvements. The lead/lag configuration utilizes the lag vessel (second vessel) as a redundant
barrier against arsenic breakthrough during treatment. In the event that arsenic levels have broken
through the lead vessel (first vessel), the lag vessel can still remove arsenic and help eliminate any
MCL exceedances. The presence of a lag vessel allows for complete exhaustion of the lead vessel,
running the lead vessel until effluent arsenic levels equal the influent water levels; therefore
maximizing use of the media. After the lead vessel reaches exhaustion, the media in that vessel
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Pomerene Domestic Water Improvement District
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can be replaced, and the vessel is used in the lag position with the previous lag vessel becoming
the lead vessel. The media change out in the lead and lag vessels is typically staggered and not
performed concurrently. This approach maximizes the use of the media, protects the water system
against rising arsenic levels as the media is exhausted and reduces the risk of MCL violations.
Existing Water System Operation
The water system is operated using a control system which automatically rotates well operation to
cycle the wells. This control system does not allow the operator to prioritize which wells to run,
but simply turns on the next well in sequence as water is demanded by the storage tank. All wells
turn on and off based on the levels in the storage tank. Well No. 2 delivers directly to the storage
tank via a dedicated transmission main, whereas Wells 3 and 4 pump into the distribution system
and indirectly fill the storage tank through the distribution system. When all wells are off, the
storage tanks serve the distribution system demands via gravity.
2.3 ALTERNATIVES CONSIDERED
The Project alternatives are:
• Alternative 1 - No Action (no change)
• Alternative 2 - Direct Delivery of Water from Well No. 6 to the Distribution System
• Alternative 3 - Deliver and Blend Water from Well No. 6 with Well No. 2
• Alternative 4 - Deliver and Blend Water from Well Nos. 2, 3, and 6 at the Storage Tank
• Alternative 5 - Deliver and Blend Water from Well Nos. 2, 4, and 6 at the Storage Tank
• Alternative 6 - Deliver and Blend Water from Well Nos. 2, 3, 4 and 6 at the Storage Tank
(Preferred Alternative)
• Alternative 7 - Deliver and Blend Water from Well No. 6 at Well No. 2 and Install New
Fluoride Treatment
Alternative 1 — No Action
The No Action Alternative is intended to be used as the baseline alternative to compare all viable
options. If the project is not implemented, PDWID will be unable to ensure compliance with
current drinking water quality standards and episodic violations of the arsenic MCL and fluoride
secondary MCL are expected. The No Action Alternative does not protect public health or ensure
that the water meets drinking water quality standards.
Action Alternatives
In selecting the action alternatives, several criteria were utilized:
All alternatives must meet system-wide compliance with the arsenic primary MCL of 10
ppb;
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Pomerene Domestic Water Improvement District
Drinking Water Quality Improvements
Environmental Assessment
All alternatives must meet system-wide compliance with the fluoride primary MCL of 4.0
mg/L;
System-wide blending and fluoride treatment alternatives should be identified to meet the
fluoride secondary MCL of 2.0 mg/L; and
Consistency and reliability of long-term compliance must be considered in identifying and
selecting alternatives.
Alternative 2 — Direct Delivery of Water from Well No. 6 to the Distribution System
This alternative involves the equipping new Well No. 6 for production, and construction of a well
delivery line from Well No. 6 directly to the distribution system by connecting to the existing 6-
inch water line along Diamond Back Road at the southeastern edge of the water system. No
changes to the existing operation and treatment at other wells are considered with this alternative.
In addition to the well and pipeline improvements, modifications are also recommended for the
well control system at PDWID. Currently, the wells cycle sequentially in a set order that cannot
be controlled or modified by the operator, which limits the operator's ability to preferentially use
certain wells to achieve any water quality or blending goals. The proposed control system
modifications would include providing a new telemetry system for the wells and the storage tanks
that provides for enhanced control of water system well operations. The wells would continue to
operate based on the tank levels; however, the control system could be programmed to optimize
the run times of each well based on arsenic and fluoride water quality parameters.
Absent any other modifications to the water system, the mode of operation in this alternative will
not likely result in compliance with secondary standards for fluoride, although "incidental"
blending in the storage tank may still provide some mitigation of fluoride levels. Therefore,
PDWID would be required to provide public notices and likely perform enhanced sampling due to
the secondary fluoride MCL violations.
The following infrastructure will be required for this alternative:
Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• 1,500 linear feet (If) of 6-inch water line from Well No. 6 to the existing 6-inch along
Diamond Back Road; and
System-wide telemetry control system.
The following operational changes would be implemented under this alternative:
Well No. 6 EPDS will be at the Well No. 6 site;
Programming of the new well control system would likely be set for Well Nos. 3 and 4 to
function as the primary wells, with operational cycling of the other wells;
Well No. 2 would continue to be treated for arsenic; however, treated and bypass flows
could be adjusted to better match the system conditions; and
Interlocking of wells is not anticipated under this scenario; all wells would operate
independent of each other.
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Alternative 3 — Deliver and Blend Well No. 6 with Well No. 2
This alternative involves no changes to the existing operation of Well Nos. 3 and 4. However
there will be blending of Well No. 6 with Well No. 2 (after Well No. 2 arsenic treatment). This
alternative requires equipping new Well No. 6 for production, and a 6-inch transmission main from
the Well No. 6 site to the Well No. 2 site. After blending, water from Well Nos. 2 and 6 will be
delivered to the storage tank via the existing 6-inch transmission line. The Well No. 2 treatment
configuration would be modified to provide two 48-inch FRP vessels installed in a lead/lag
treatment configuration to treat 100 gpm.
The following infrastructure will be required for this alternative:
Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• Approximately 7,300 If of 6-inch transmission line from Well No. 6 to Well No. 2. It is
noted that there will not be any customers connected to this pipeline;
Arsenic treatment modifications at Well No. 2 to allow for lead/lag operation; and
System-wide telemetry control system.
The following operational changes would be implemented under this alternative:
Well No. 2 and Well No. 6 will be combined into one entry point distribution system
(EPDS) leaving the storage tanks;
Programming of the new well control system would likely be set for Well Nos. 2 and 6 to
function as the primary wells, with operational cycling of the other wells; and
Interlocking of wells is not anticipated under this scenario and all wells would operate
independent of each other.
Alternative 4 — Deliver and Blend Well Nos. 2, 3, and 6 at the Storage Tank
Delivery of treated water from Well No. 3 would discharge directly to the storage tank via a new
transmission main, and blending Well No. 6 with treated water from Well No. 2 via a new
transmission main and delivery to the storage tank similar to Alternative No. 3. Similar to
Alternative 3, modifications to the arsenic treatment system at Well No. 2 would be performed,
including installing an additional 48-inch FRP vessel and reconfiguring of the piping to allow for
lead/lag configuration to treat 100 mgd. Additionally, the Well No. 3 treatment configuration
would be modified to provide two 48-inch FRP vessels installed in a lead/lag treatment
configuration to treat 80 gpm. The existing concrete pad and enclosure would be extended to
accommodate the additional vessel. Similar to the other alternatives, a new system-wide telemetry
control system would be provided. This alternative involves no changes to the existing operation
of Well No. 4.
The following infrastructure will be required for this alternative:
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Pomerene Domestic Water Improvement District
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Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• Approximately 7,300 linear feet (If) of 6-inch transmission line from Well No. 6 to Well
No. 2;
Approximately 3,700 If of 4-inch transmission line from Well No. 3 to the storage tank;
Arsenic treatment modifications at Well Nos. 2 and 3 to allow for lead/lag operation; and
System-wide telemetry control system.
The following operational changes would be implemented under this alternative:
Blending with Well No. 6 and treatment modifications at Well No. 2 will be similar to
Alternative 3; and
Well Nos. 2, 3, and 6 will be combined into one EPDS leaving the storage tanks.
There are no well combinations utilizing Well No. 6 that meet the secondary fluoride MCL due to
the high levels of fluoride in Well No 6. Many of the scenarios meet the compliance goal of 80
percent of the primary fluoride MCL. Scenarios that provide sufficient flow to meet the peak daily
demand (PDD) do not meet the secondary fluoride MCL. It is noted that arsenic levels under this
alternative are below the arsenic MCL due to treatment employed at Well Nos. 2 and 3.
Alternative 5 — Deliver and Blend Well Nos. 2, 4, and 6 at the Storage Tank
This alternative involves performing no changes to the existing operation of Well No. 3. Delivery
of treated water from Well No. 4 would discharge directly to the storage tank via a new
transmission main, and blending Well No. 6 with treated water from Well No. 2 via a new
transmission main and delivery to the storage tank similar to Alternatives 3 and 4. Modifications
to the arsenic treatment system at Well No. 2 would be performed, including installing one
additional 48-inch vessel and reconfiguring the piping to allow for lead/lag. Additionally, the
existing vessels at Well No. 4 would be replaced with two new 60-inch steel vessels installed in a
lead/lag configuration to treat 120 gpm. New piping and valves would be provided to allow for
lead/lag operation; although it is assumed that a new concrete pad would be installed to
accommodate the vessels but the steel vessels would not be enclosed. Similar to the other
alternatives, a new system-wide telemetry control system would be provided.
The following infrastructure will be required for this alternative:
Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• Approximately 7,300 linear feet (If) of 6-inch transmission line from Well No. 6 to Well
No. 2;
• Approximately 5,400 If of 4-inch transmission line from Well No. 4 to the storage tank;
Arsenic treatment modifications at Well Nos. 2 and 4 to allow for lead/lag operation; and
System-wide telemetry control system.
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The following operational changes would be implemented under this alternative:
Blending with Well No. 6 treatment modifications at Well No. 2 will be similar to
Alternatives 2 and 3; and
Wells Nos. 2, 4 and 6 will be combined into one EPDS leaving the storage tanks.
There are no well combinations utilizing Well No. 6 that meet the secondary fluoride MCL due to
the high levels of fluoride in Well No 6. Many of the scenarios meet the compliance goal of 80
percent of the primary fluoride MCL. Scenarios that provide for the PDD do not meet the
secondary fluoride MCL. It is noted that arsenic levels under all scenarios are below the arsenic
MCL due to treatment employed at Well Nos. 2 and 3.
Similar to Alternative 4, the rationale behind the well utilization is to maximize operation of Well
Nos. 2, 4, and 6 to achieve some level of fluoride blending to reduce system-wide fluoride levels;
Well No. 3 would be used as a backup. Under the proposed well operational scenario, if Well No.
2 supplies 25% of the flow, Well No. 3 -15% of the flow, Well No. 4 - 30% of the flow and Well
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Pomerene Domestic Water Improvement District
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Out of Operation
Well No 2
Flow 100 opm
Ansemc 10.8 ppb
Fluoride 3.4 mgA»
Provide two 604nch
Veaaels forLe»dA.«g
Treatment Configuration
Will Ho 3
Flow 90 gpm
Arsenic 22 3 ppo
Fluoride 0 4 mg/L
Q'dP^r.n.fe
Deliver Water to the
Storage Tank and
Blend w
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Pomerene Domestic Water Improvement District
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No. 6 - 30% of the flow, on average, over time the weighted, blended fluoride level in the overall
system is estimated to be approximately 2.4 mg/L.
Alternative 6 — Preferred Alternative - Deliver and Blend Well Nos. 2, 3, 4, and 6 at the Storage
Tank
This alternative involves constructing new well transmission mains to combine and deliver Well
Nos. 3 and 4 to the storage tank, and blending Well No. 6 with treated water from Well No. 2 via
a new transmission main and delivery to the storage tank similar to Alternatives 3, 4, and 5. There
will be several well operational constraints if this alternative is implemented, but this option would
allow for maximum flexibility in blending low-fluoride water from Well Nos. 3 and 4 with high-
fluoride water from Well Nos. 2 and 6. See Figure 10 from the Pomerene EID for a map of
Preferred Alternative 6.
Similar to Alternatives 3, 4, and 5, modifications to arsenic treatment systems at Well Nos. 2, 3,
and 4 would be performed to allow for lead/lag configuration. As with the other options, a new
system-wide telemetry control system would be provided.
The following infrastructure will be required for this alternative:
Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• Approximately 7,300 If of 6-inch water line from Well No. 6 to Well No. 2;
• Approximately 2,400 If of 4-inch water line to deliver from Well No. 4 across Tumbleweed Lane
to Old Pomerene Road and Whiskey Road;
• Approximately 700 If of 4-inch water line to deliver from Well No. 3 to Old Pomerene Road and
Whiskey Road;
• Approximately 3,000 If of 4-inch water line to deliver from Old Pomerene Road and Whiskey
Road across Whiskey Road and Sonora Verde Drive to the storage tank site;
Arsenic treatment modifications at Well Nos. 2, 3, and 4 to allow for lead/lag operation;
and
System-wide telemetry control system.
The following operational changes would be implemented under this alternative:
Well Nos. 2, 3, 4, and 6 will be combined into one EPDS leaving the storage tank;
All wells will feed the storage tanks, and the tanks will float the system to meet water
system demand; and
An ADEQ-approved blending plan would be required which will be incorporated into the
new telemetry control system to ensure operation of well combinations per the blending
plan requirements.
Out of 15 well operational scenarios possible under this alternative, seven scenarios meet
the secondary fluoride standard, and 12 scenarios meet the compliance goal of 80 percent
of the primary fluoride MCL. There are two scenarios that provide for the PDD while
complying with secondary fluoride MCL; one well combination utilizing Well No. 6 meets
the secondary fluoride MCL. It is noted that arsenic levels under all operational scenarios
are below the arsenic MCL. Under the proposed well operational scenario, if Well No. 2
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Environmental Assessment
supplies 20% of the flow, Well No. 3- 30% of the flow, Well No. 4 - 30% of the flow and
Well No. 6 - 25% of the flow, on average, over time the weighted, blended fluoride level
in the overall system is estimated to be approximately 2.0 mg/L.
Alternative 7 — Deliver and Blend Well No. 6 at Well No. 2 and Install New Fluoride Treatment
This alternative relies on treatment for Well Nos. 2 and 6 to ensure compliance with the fluoride
secondary and arsenic standards, and continues to utilize the existing facilities at Well Nos. 3 and
4 for arsenic compliance. A 6-inch well transmission line will be constructed to deliver water from
Well No. 6 to Well No. 2. Similar to the other alternatives, a new well telemetry control system
would be provided.
The following systems and constraints for fluoride treatment were considered:
Absorption treatment using activated alumina (AA) - This is an adsorption-based
technology to 6.5). Chemical media regeneration is performed in-situ after media is
exhausted. Treatment system operation will require onsite chemical storage and hauling
spent chemicals after media regeneration. For budgetary purposes, it is estimated that a
200 gpm treatment system will be installed to treat Well Nos. 2 and 6 and reduce fluoride
levels to less than 2.0 mg/L. Although trace levels of iron are detected in the water, it is
assumed that removal of iron prior to fluoride treatment will not be required and can be
handled by a micron pre-filtration system;
Reverse Osmosis (RO) - This technology utilizes membrane-based RO technology to treat
well flows. Both wells will discharge into a new treatment feed storage tank and will be
pumped at high pressures through the RO system and delivered to the existing 530,000-
gallon storage tanks. For budgetary purposes, it is estimated at a 150 gpm RO system will
be provided to reduce fluoride levels at Well Nos. 2 and 6 to less than 2.0 mg/L.
Although trace levels of iron are detected in the water, it is assumed that removal of iron
prior to fluoride treatment will not be required and can be handled by a micron pre-filtration
system;
It is assumed that if fluoride treatment is implemented, the arsenic treatment at Well No.
2 will not be required; the fluoride treatment process will also treat for arsenic; and
It is recommended that a detailed evaluation of treatment alternatives including waste
disposal alternatives be performed prior to implementing this alternative.
The following infrastructure will be required for this alternative:
Well No. 6 pumping equipment including new power supply (existing three phase power
is approximately 500 feet away from the well site), electrical, controls and civil site work;
• Approximately 7,300 If of 6-inch water line from Well No. 6 to Well No. 2;
Fluoride treatment system for Well No. 2 and 6 installed at Well No. 2; and
System-wide telemetry control system.
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2.4 OTHER ALTERNATIVES CONSIDERED BUT NOT EVALUATED
This section presents other alternatives that were considered but were not evaluated due to cost
considerations or feasibility.
Utilize Existing Interconnect with the City of Benson
This alternative considers the opportunity to utilize the existing 6-inch interconnect with the City
of Benson for water delivery. The 6-inch interconnect, located near Pomerene Road and Via
Estaca Road, is in the south portion of the water system. Based on the information obtained from
PDWID, the interconnection was primarily installed under an agreement with the City of Benson
to provide additional fire flow capacity for the nearby church property, if required. The water
pressure in the City of Benson water system at this location is reported to be approximately 60 psi.
Based on the water system model analysis, this pressure would be sufficient to serve the PDWID
system.
However, a comparison of the City of Benson's and PDWID's tariff reveals that utilizing the
interconnect with city of Benson would not be a favorable financial decision for the PDWID,
unless PDWID is able to negotiate a discounted rate and enter in a legal agreement with city of
Benson. In addition to the tariff rates, it should be noted that the actual cost of operation of an
individual well in the PDWID is lower than PDWID's tariff rate, further indicating that replacing
well capacity with city of Benson capacity would not be financially favorable.
Isolate the Dairy Farm from the Potable Water System
A single dairy farm customer (with multiple meters) constitutes approximately 12 to 14 percent of
the PDWID water system demand on an annual basis. Since dairy farms typically do not require
potable water for cattle feed and operations, consideration was given to isolating the dairy from
the potable water system. Under such an alternative, a non-potable water line would be constructed
to serve the dairy's nonpotable water needs. This could be achieved by connecting discharge from
one of the Pomerene wells directly to the dairy farm. However, due to following reasons, this
alternative was not evaluated further:
Due to the cost of water line construction (approximately 4,000 feet of 2-inch water line
and hydropneumatic tank for well control at a cost of approximately $150,000) compared
to the potential operating cost savings (up to approximately $4,000 per year for reduced
arsenic treatment media usage), this alternative did not appear to warrant further
consideration;
Relying on only one well for service to the dairy farm does not allow the water system to
have redundancy of service to this customer if the well is out of service, and would likely
require some sort of manual switchover to a backup supply from the drinking water system
during outages;
It is not considered a good long-term well pump operating scenario to have the pump
turning on and off based on pressure control to serve the demands of the dairy. Frequent
on and off operation of well pumps can shorten pump lifespan;
Control and operation of well would be fairly complicated if the scenario also attempted
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to maintain well availability to the drinking water system through the arsenic treatment
plant, as there would be multiple inputs controlling the well starts and stops, and automated
control valves would likely be required to ensure water was being sent to the correct
demand; and
This alternative fundamentally assumes that the dairy farm can operate on non-potable
water. However, there may be unknown stipulations from dairy's clients that the dairy is
required to meet, which could prohibit implementation of this alternative.
3.0 AFFECTED ENVIRONMENT
The purpose of this section is to describe the environmental resources that could potentially be
impacted by the project alternatives described in Section 2.0. The descriptions of the affected
environment focus on environmental resources located within the proposed project area and
adjacent areas.
Pomerene is a small unincorporated community in Cochise County, Arizona, United States.
Pomerene is 2 miles (3.2 km) north of Benson. PDWID estimates that they currently provide
domestic water to 900 customers.
The Pomerene area has a semi-arid climate with hot summer days, moderate winter days, and low
humidity. Average monthly temperature range from 30 degrees Fahrenheit in January to 97 degree
Fahrenheit in June. Average rainfall is 11.3 inches per year and snowfall is 1.8 inches per year.
3.1 LAND USE
Existing land uses within the project area include utility and transportation (paved and unpaved
roads) infrastructure. Adjoining land use includes residential development, churches and public
services, limited open space, and agricultural lands. According to land use designations mapped
for the Cochise County Comprehensive Plan, the project area is mainly within a Category B
Growth Area, which is defined as an area that is in transition from a rural environment to a more
urban environment.
Existing utilities occur in several roadways included in the project area. Formal roads include
Pomerene Road, Old Pomerene Road, Sonoita Verde, and Diamondback Drive. The west half of
Diamondback Drive is not paved and the east half of Diamondback Drive is not developed as a
road. One corridor occurs along land without existing right-of-way or improved roads (runs along
the east side of the PDWID boundary) then runs across undeveloped land to an existing well site.
Portions of this segment have an existing, informal road.
3.2 PHYSIOGRAPHY, TOPOGRAPHY, GEOLOGY AND SOILS
The project area is located in southeastern Arizona within San Pedro River valley. This portion of
the valley is flanked by the Rincon Mountains on the west and the Little Dragoon Mountains on
the east. It encompasses three major environmental zones: mountains, bajadas, and river
floodplains and terraces. The Project area is east of the San Pedro River at the interface of the
floodplain and the distal bajada emanating from the Little Dragoon Mountains in an area of gently
sloping floodplain terraces dissected by shallow drainages.
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Most of the project area is mapped as Late Holocene alluvium that formed on low terraces, alluvial
fans, and small channels in association with the modern drainage system (Youberg et al. 2009).
In lower piedmont areas, such as the Project area, this unit is predominantly moderately sorted
sand and silt, with some pebbles and cobbles in channels. Some small hills in the Pomerene
vicinity are comprised of erosional remnants of older Quaternary to Tertiary basin fill alluvium,
including the Pliocene St. David formation and Pliocene to Pleistocene conglomerate and
sandstone. These units may include sandstone, conglomerate, mudstone, marl, tuff, and lacustrine
limestone.
Elevations in the project area range between 3,530 and 3,590 feet above sea level. The natural
landscape has been altered from its original state. The area immediately surrounding the project
area has been used historically and in recent times as an agricultural and residential area.
Disturbances include roads, utilities, agricultural features, and structures. Portions of land surface
along the project area have been previously developed and are now characterized by bituminous
asphalt, gravel, and improved earthen roadways; utility installations, landscaping gravel; and non-
native landscaped plants.
3.3 WATER RESOURCES
Addressing drinking water quality problems is the purpose of the proposed project. Water quality
problems related to concerns beyond the public water system may be evaluated in connection to
habitat and wildlife. However, there are no perennial or intermittent sources of water within the
project area. Ephemeral drainages that cross the project area flow only in response to rainfall.
PDWID relies on groundwater as their drinking water source. Water quality concerns in the
PDWID have not been attributed to harming aquatic life.
ADEQ monitors and assesses surface water quality along selected reaches of the San Pedro River
in relation to state water quality standards. The monitored reach of the San Pedro River nearest
and down gradient from the project area is the 15.5-mile reach that occurs between the Dragoon
Wash and Tres Alamos Wash. This reach has been designated in past years as an impaired water
for nitrate concentrations but recent monitoring was inconclusive. It is no longer identified as
impaired for nitrate. This portion of the San Pedro River is down gradient of Apache Nitrogen
Products (formerly known as Apache Powder Company), which is listed on numerous government
monitoring databases, including those related to CERCLA ("Superfund") for potentially
contributing to water quality concerns.
Management and conservation of water resources in Arizona is the responsibility of the Arizona
Department of Water Resources (ADWR), which regulates water service providers in accordance
with Arizona Revised Statutes (ARS). Providers located outside Arizona Active Management
Areas, (such as PDWID) submit system water plans and annual water use reports to ADWR
pursuant to A.R.S. §§ 45-342 and 343. While regional drought and long-term water availability is
a concern for Arizona, based on the data provided by PDWID it appears that wells for the Project
have adequate water supply. Pump testing for new wells (such as Well No. 6) and well system
analysis indicate there is sufficient water available for the community.
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Surface and Groundwater Hydrology
The project area generally slopes from the northeast to the southwest toward the San Pedro River.
Regionally, water flows from the mountain slopes toward the central San Pedro valley then
northward along the San Pedro River. Several minor ephemeral drainages cross the project area,
generally flowing from north and east, southwest toward the San Pedro River. None of these
drainages are named washes on the USGS topographic maps. No special aquatic resources as
defined by the U.S. Army Corps of Engineers are present within the project area.
The project area is located in the western portion of the Upper San Pedro Watershed (hydrologic
unit code [HUC] 15050202) where basin fill is the principal aquifer with some areas utilizing
stream alluvium. Groundwater flow is assumed to generally follow surface gradient. Groundwater
in the basin fill aquifer is found in both unconfined and confined conditions, and artesian
conditions exist near Benson and Saint David. Based on ADWR records from 1990 to 1991 and
2003 to 2004, water levels declined in most wells in the basin but groundwater levels in some
wells have risen up to 0.6 feet per year in the Pomerene area north of Benson. Drillers' logs from
ADWR and Groundwater Site Inventory (GWSI) databases indicate that wells in the general
vicinity of Pomerene are screened in either a shallow, unconfined aquifer or a deeper, basin fill
aquifer. The shallow aquifer can be highly productive (greater than 1,000 gpm). The deep aquifer
in Pomerene is confined below a thick (approximately 200 to 500-plus feet) interval of red clay.
PDWID Well Nos. 2, 3, 4, 5, and 6 are screened in this deep aquifer. Artesian conditions are
present at Well No. 5, according to the driller's log. Confined groundwater conditions (but not
artesian) are present in Well Nos. 2, 3, 4, and 6.
There are well-known public concerns related to water resources for the San Pedro River
watershed. Portions of the river are perennial; however, the relevant reach of the San Pedro River
adjacent to the project area is designated by ADWR as an intermittent stream, and other sources
report the stream as frequently dry.
Wetlands
The USFWS hosts an interactive mapping service that depicts mapped "wetlands" for the United
States from a biological context. The wetland inventory map does not report any wetlands within
the project area. However, several ephemeral drainages cross the project area. Based on review
of aerial and topographic maps and observations during the site visit, there is potential that some
ephemeral drainage features that cross the project area would be considered jurisdictional wetlands
(i.e. waters of the United States) by the EPA and Corps. Specifically, there are several drainage
features that exhibit ordinary high water mark (OHWM) indications. The Pomerene Canal
intercepts several washes in the vicinity of the project area but it is breached in several locations
and does not appear to convey water where it crosses the proj ect area. It is unlikely that the Corps
would assert jurisdiction over the Pomerene Canal for this project but it is likely that other
ephemeral drainage features within the project area may be considered waters of the United States.
Floodplains
The Federal Emergency Management Agency (FEMA) has mapped flood zones on their Flood
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Insurance Rate Maps (FIRMs) that cover the project area. The FIRM (Panel number
0400120563B) depicts the varying levels of flood risk mapped for the project area. The project
area occurs mainly in Zone X outside the 500-year floodplain, a minimal risk designation (outside
the 1-percent and ,2-percent-annual-chance floodplain). No base flood elevations or depths are
shown in these zones. A portion of one corridor (along the east PCWID boundary) crosses land
with Zone A designation; area within the 100-year floodplain. Zone A is defined as a special flood
hazard area inundated by 100-year flood (subject to inundation only during the 1-percent-annual-
chance flood event). No detailed analysis is performed for Zone A; therefore, no base level flood
elevations have been determined.
3.4 VEGETATION
The project area is highly disturbed by formal and informal roadways. Undeveloped portions of
the project area have native vegetation dominated by mesquite, acacia, prickly pear, and native
and non-native intrusive grasses. The project area and surrounding lands are consistent with the
Chihuahuan desertscrub biotic community. Vegetation on undeveloped portions of the Project area
was consistent with Chihuahuan desertscrub vegetation: dominated by creosotebush (Larrea
tridentata), tarbush (Fourensia cernua), whitethorn acacia (Acacia neovernicosa), catclaw (Acacia
greggii), ocotillo, allthorn, and mesquite. Major understory species include various species of
agave (Agave lechuguilla, A. scabra, A. falcata, A. neomexicana, A. parryi, A. striata), yuccas
{Yucca elata, Y. rostrata, Y thompsoniana, Y filifera, Y. carnerosana, Y. torreya), sotols
(Dasylirion leiophyllum, D. wheeleri), and nolinas (Nolina microcarpa, N. erumpens, N. texana),
along with a variety of small cacti.
3.5 WILDLIFE RESOURCES
Fish and Wildlife
The project area is limited and comprised primarily of plants and animals with no special status
protection occurring along roads, in yards, and along adjacent farm plots. Trenching and laying
pipes would occur at sites and properties that are already disturbed, thus largely avoiding
disturbance of wildlife habitat. There is no fish habitat occurring within the project area.
Federally Endangered & Threatened Species
A screening analysis was conducted to evaluate the potential for occurrence of federally threatened
and endangered species at the project area. The methods and result of this evaluation are presented
below.
Screening Analysis Methods
The list of Special-status Species evaluated for the project was obtained from the Arizona
Ecological Field Office of the U.S. Fish and Wildlife Service (USFWS) website using the PDWID
district boundary. A screening analysis was then conducted to evaluate the potential for occurrence
of Special-status Species and the presence of proposed or designated critical habitat for listed
species within the project area. Special-status species are those that are listed as endangered or
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threatened, proposed for listing, or candidate for listing by the USFWS. Determinations of the
potential for Special-status Species to be present and to utilize habitats within the project area were
based on: 1) field observations and habitat assessments of the project area; 2) review of the natural
history of the Special-status Species; 3) evaluation of the known ranges and distributions for the
Special-status Species; 4) comparisons of this information with habitats present in the Project area;
and, in some cases, 5) review of records of occurrences in published or gray literature.
Field reconnaissance was conducted on May 28 and July 18, 2014, to identify habitat types in the
area and evaluate the potential for any Special-status Species to be present in the project area.
During these field visits, biologists recorded plant and wildlife species observations and took
photographs in the project area. No species-specific surveys were conducted during the site visits.
Occurrence records were obtained through a query of Arizona Game and Fish Department (AGFD)
records, searching for known occurrences of species tracked by the Heritage Data Management
System (HDMS). The HDMS includes records for, but is not necessarily limited to, USFWS
species of concern, species considered sensitive by the Bureau of Land Management's (BLM)
Arizona State Office, species considered sensitive by the Regional Forester, species listed by the
Arizona Department of Agriculture as Salvage Restricted, and species listed by the AGFD as
Wildlife of Special Concern in Arizona. These species are not necessarily afforded protection
under the ESA. On June 18, 2014, the AGFD conducted a query of the HDMS for the PDWID
district. The HDMS search results included occurrences of Special-status Species as well as other
species of conservation concern that have been reported within 3 miles of the PDWID district.
Based on the results of the background research and field reconnaissance described above, species
were eliminated from further consideration if published habitat requirements were determined to
not be present within the project area or if the known range or distribution of the species was
outside the project area.
Screening Analysis Results
The USFWS identified 13 Special-status Species for the project area (four endangered, one
threatened, two proposed threatened, five candidate, and one experimental population) and
designated critical habitat for one species that should be considered for an effects analysis for the
project. One plant, one invertebrate, one amphibian, two reptile, five bird, and three mammal
species are listed. A screening analysis of these Special-status Species was performed to determine
which species have the potential to be present in the project area (See Table 1 in the Appendix).
Species with more than a limited potential to be present within the project area or its immediate
vicinity are highlighted in bold in Table 1.
The AGFD HDMS Environmental Review Tool reported no USFWS species with listed federal
status within 3 miles of the district. It did report two USFWS species that are given special
consideration for future listing within 3 miles (4.8 km): the Sonoran desert tortoise (Gopherus
morafkai), which is considered a USFWS candidate species, and the Needle-spine pineapple
cactus, which is considered a USFWS Species of Concern. These species are not currently
afforded protection under the ESA; however, the Sonoran desert tortoise was considered in this
evaluation for its likely potential to be listed in the future.
The criteria used to classify the potential for occurrence of the 13 species included in this screening
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analysis are defined as follows:
Present - The species has been observed to occur in the project area during the site visit or
pursuant to the AGFD records or other reliable source; the project area is within the current known
range of the species; and habitat characteristics required by the species are known to be currently
present.
Possible - The species has not been documented in the project area, but the known, current
distribution of the species includes the project area and the required habitat characteristics of the
species appear to be present in the project area.
Limited Potential - Generally, the known, current distribution of the species does not include the
Project area, but the distribution of the species is close enough such that the Project area may be
within the dispersal distance of the species. The habitat characteristics required by the species may
be present in the project area. In general, the potential for occurrence of these species is considered
insignificant to the point that detailed discussion is not warranted.
No Potential - The project area is outside the known distribution of the species and the habitat
characteristics required by the species are not present.
Based on the screening analysis, one of the 13 Special-status Species is considered to have more
than limited potential to occur at the project area and was evaluated further. There are no federally
listed species (species with threatened and endangered status) with more than limited potential to
occur in the project area. It is possible that the Sonoran desert tortoise will be present in the project
area but as explained below, considering that habitat for the desert tortoise is marginal in the
project area and that records for Sonoran desert tortoise east of the San Pedro River in Cochise
County are sparse, the Sonoran desert tortoise is considered to have a low probability of occurrence
in the project area. Adverse impacts to the Sonoran desert tortoise are not expected, though
dispersing individuals cannot be completely discounted from having any potential to occur in the
project area. The Sonoran desert tortoise is not yet afforded protection under the ESA. The project
is not expected to result in a trend toward a federal listing of the Sonoran desert tortoise. Additional
discussion for Sonoran desert tortoise is provided below. Table 1 provides justification for the
determination for whether a species are likely to occur in the project area and subsequent
determination for the project's potential to impacts these species if they have potential to occur in
the project area
Sonoran Desert Tortoise
The Sonoran desert tortoise is currently a candidate for listing. It was petitioned for listing as a
Distinct Population Segment with critical habitat on October 9, 2008). On August 28, 2009, the
USFWS published its 90-day finding announcing that they were initiating a status review for the
Sonoran desert tortoise. On December 14, 2010, the USFWS announced that the listing of the
Sonoran desert tortoise was warranted but precluded by higher priority listing actions (USFWS
2010b). The May 10, 2011, WildEarth Guardians v. Salazar court settlement requires the USFWS
to submit a Proposed Rule or a not-warranted finding to the Federal Register for the Sonoran
desert tortoise no later than the end of FY 2015 (September 30, 2015). The Sonoran desert tortoise
is also designated Arizona State Wildlife of Special Concern, Forest Service Sensitive, and BLM
sensitive. The Sonoran desert tortoise is not currently afforded protection under the ESA, but it is
considered in this report due to the potential for listing.
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The desert tortoise requires adequate shelter to escape extreme winter and summer temperatures.
The Sonoran population typically excavates or modifies burrows under rocks and boulders, but
also excavates under shrubs or open ground and uses rock crevices and caliche caves along dry
arroyos for shelter. Sonoran desert tortoises are observed most commonly on steep, rocky slopes
and bajadas at elevations between 510 and 5,300 feet. The project area was surveyed by a biologist
familiar with the habitat requirements for this species. The proj ect area lacks rocky slopes with the
exception of the small hill where the water towers are located. No appropriate shelter sites (rocky
slopes, caliche dens, other hard cover) were observed. Additionally, no sign, tracks or individual
tortoise were observed during the site visit. The potential for occurrence of desert tortoise is
expected to be low.
As indicated above, records for Sonoran desert tortoise east of the San Pedro River in Cochise
County are sparse. There is a record for this species within three miles of the project area, but
records of isolated occurrences in uncharacteristic environments have led to the suspicion that
observed Sonoran desert tortoise were captive-release tortoises or misidentified desert box turtles
(.Terrapene ornata luteola). However, these records could represent locally present populations
of desert tortoise. Population cores are typically on mountain slopes, with tortoises radiating out
from these slopes, often along washes that offer caliche or conglomerate cave shelter opportunities.
Core populations remain throughout their Arizona range. Concerns about population genetics have
arisen due to habitat fragmentation and increased barriers to tortoise movement across the valleys
between mountain ranges as a result of the construction of roads, canals, and railroads and urban
development.
In summary, the project area generally lacks the suitable habitat characteristics preferred by the
Sonoran desert tortoise. Adverse impacts to the Sonoran desert tortoise are not expected, though
dispersing individuals have the potential to occur in the project area.
Migratory Birds
Migratory birds and their occupied nests or eggs are protected by the Migratory Bird Treaty Act
(MBTA). The MBTA is administered by USFWS and, in part, prohibits harming protected birds
or destroying their eggs or occupied nests. It subjects violators to liability with the potential for
penalties including fines and imprisonment for such activity. There are hundreds of migratory bird
species protected by the MBTA. Within the project area, suitable habitat is relatively minor when
compared to the surrounding area
3.6 CULTURAL RESOURCES
A Cultural Resource Inventory was conducted for the project, which n identified one new
archeological site, AZ EE:3:255(ASM)—The Pomerene Road Network—and two isolated
occurrences. Two previously recorded sites, AZ EE: 13:85(ASM)—The Pomerene Canal—and AZ
CC:13:80(ASM)/AZBB:13:760(ASM)—The Tucson-Apache Transmission Line—are located
within the proposed alignment Corridors. The Pomerene Canal is a historic property determined
eligible for inclusion in the National Register of Historic Places (NRHP) and it crosses all proposed
alignment corridors. The Tucson-Apache Transmission Line crosses portions of the proposed
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corridor; however, this site has been determined ineligible for inclusion in the NRHP. Newly
recorded site, the Pomerene Road Network, AZ EE:3:255, is recommended as ineligible for
inclusion in the NRHP since it does not have distinctive characteristics that distinguish it from
innumerable rural community road networks across Arizona and the United States.
3.7 AIR QUALITY
The Clean Air Act (CAA) requires EPA to establish primary and secondary National Ambient Air
Quality Standards (NAAQS) for criteria pollutants, and states are required to develop State
Implementation Plans (SIPs) describing how NAAQs will be met. Geographic areas that do not
meet the NAAQs are designated as Nonattainment areas for relevant pollutants. Air emissions are
regulated under the CAA in the context of NAAQs, and authority to enforce the CAA may be
delegated by the EPA to state or county agencies. Air emissions are generally regulated through
permitting requirements, emission standards for mobile and stationary sources, performance
standards for new or modified existing stationary sources, emission standards for hazardous air
pollutants, air toxic standards, and restrictions to prevent significant deterioration of clean air
areas. The CAA also ensures the preservation of air quality and visibility in our national parks and
wilderness areas.
Involvement of a federal agency can expand air pollution prevention efforts for certain activities.
Federal agencies must demonstrate that their actions conform to any SIP approved under Section
110 of the CAA (42 USC §7506(c)). A conformity determination may be required for a federal
action that occurs in a non-attainment or maintenance area. In accordance with the Clean Air Act
(CAA), the EPA sets National Ambient Air Quality Standards (40 CFR part 50) for six criteria
pollutants that are deemed harmful to public health and safety. These six criteria pollutants are
carbon monoxide (CO), lead (Pb), particulate matter less than 10 and 2.5 microns in aerodynamic
diameter (PMio and PM2.5), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2). The
project area is not within or adjoining a Nonattainment Area. The closest Nonattainment Area is
the Paul Spur/Douglas Planning Area (PM10 Nonattainment Area), which is approximately 43
miles southeast of the project area in south central Cochise County. There are two areas near the
project area that have been redesignated to Attainment Areas and are now under Maintenance
Plans: Tucson (CO Attainment with Maintenance Plan) and San Manuel (SO2 Attainment with
Maintenance Plan) located 22 miles west of and 37 miles northwest of the project area,
respectively.
Under Section 162(a) of the CAA, Class 1 federal lands or air sheds are granted special air quality
protection. Class 1 federal air sheds include areas such as national parks, national wilderness areas,
and national monuments. The 71,400-acre Saguaro Wilderness Area is the closest Class 1 federal
air shed to the project area (40 CFR § 81.403). The project area is located more than 10 miles
southeast of the Saguaro Wilderness Area.
3.8 NOISE
Noise is generally described as unwanted sound, which can be based either on objective effects
such as hearing loss or damage to structures or subjective judgments such as community
annoyance. Sound usually represented on logarithmic scale with a unit called the decibel (dB).
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Sound on a decibel scale is referred to as sound level. The threshold of human hearing is
approximately 3 dB, and the threshold of discomfort or pain is around 120 dB.
Noise levels occurring at night generally produce a greater annoyance than do the same levels
occurring during the day. It is generally agreed that people perceive intrusive noise at night as
being 10 dBA.
Acceptable noise levels have been established by the U.S. Department of Housing and Urban
Development for construction activities in residential areas: 1) Acceptable (not exceeding 65 dB);
2) Normally Unacceptable (above 65 but not greater than 75 dB); and 3) Unacceptable (greater
than 75 dB).
3.9 ENERGY AND NATURAL RESOURCES
Pomerene purchased electricity from Sulphur Springs Valley Electric Cooperative (SSVEC). The
electricity distribution system appears adequate for Pomerene's current needs as no evidence of
brownouts or other forms of power shortages was identified. Southwestern Gas Corporation
provides natural gas the Pomerene.
3.10 TRANSPORTATION
The majority of the project area is along developed roadways (Pomerene Road, Old Pomerene
Road, Sonoita Verde, and Diamondback Drive) where other public utilities are already placed. The
west half of Diamondback Drive is not paved and the east half of Diamondback Drive is not
developed as a road. One corridor occurs along land without existing right-of-way or improved
roads (along the east side of the PDWID boundary), then across undeveloped land to an existing
well site. Construction of the project would mainly affect unpaved roadsides and cross under paved
roadways.
The Federal Highway Administration Highway Functional Classification System identifies roads
as interstates, freeways, principal arterials, minor arterials, and major and minor collectors. None
of the roadways in Pomerene are classified.
3.11 HAZARDOUS MATERIALS
Hazardous materials and substances are regulated in Arizona by a combination of mandated laws
promulgated by the EPA and the ADEQ. There are no hazardous waste sites, potential hazardous
waste sites, and remedial activities, including sites that are on the National Priorities List or being
considered for the list.
3.12 SOCIOECONOMICS
Pomerene is located approximately 50 miles southeast of Tucson, Arizona, the state's second
largest populated city. Located in Cochise County, Arizona, Pomerene is two miles north of
Benson, Arizona, and approximately 40 miles north of the military post Ft. Huachuca. Pomerene
is primarily rural in character and sparsely populated. United States 2010 Census data was not
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specifically available for the PDWID service study area; however, population for a larger area
including Pomerene reports a population of 3,457. Out of the 3,457 individuals residing in that
area, 823 persons are of working age (age 19 to 44), 1058 persons are nearing or at the earlier
range of retirement age (ages 45 to 64), and there are 773 individuals over the age of 65.
The population of the Pomerene area is less racially diverse than the state of Arizona, with 92.2
percent of the population identifying as a white. Within Arizona, 73.0 percent of the population
identifies as white and within Cochise County that value is 78.5 percent.
Approximately 900 customers are estimated to be in the PDWID service area.
3.13 ENVIRONMENTAL JUSTICE
Executive Order (EO) 12898, Federal Action to Address Environmental Justice in Minority
Populations and Low-Income Populations, states that "each Federal agency shall make achieving
environmental justice part of its mission by identifying and addressing, as appropriate,
disproportionately high and adverse human health or environmental effects of its programs,
policies, and activities on minority populations and low-income populations." This action requires
all Federal agencies to identify and address disproportionately high and adverse impacts of its
programs, policies, and activities on minority and low-income populations.
EO 13045 requires each Federal agency "to identify and assess environmental health risks and
safety risks that may disproportionately affect children;" and "ensure that its policies, programs,
and activities, and standards address disproportionate risks to children that result from
environmental health risks or safety risks." This EO was prompted by the recognition that
children, still undergoing physiological growth and development, are more sensitive to adverse
environmental health and safety risks than adults.
3.14 SU STAIN ABILITY AND GREENING
In accordance with EO 13423 - Strengthening Federal Environmental, Energy, and Transportation
Management, Pomerene would incorporate practices in an environmentally, economically, and
fiscally sound, integrated, continuously improving, efficient, and sustainable manner in support of
their mission.
3.15 HUMAN HEALTH AND SAFETY
Current health concerns are associated with the Pomerene drinking water system not being in
compliance with Federal and state arsenic and fluoride standards.
4.0 ENVIRONMENTAL CONSEQUENCES
4.1 LAND USE
Under the No Action Alternative, land use will remain the same.
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Under the Action Alternatives, the project provides for upgrades, reliability improvements and
water quality improvements and increases the PDWID system source capacity by only 5 percent.
The existing water system and the water system with the proposed project improvements are both
capable of supplying the existing connections including those connections not currently in service.
The minor increase in system source capacity under the project accommodates minor infill growth,
but does not induce growth.
4.2 PHYSIOGRAPHY, TOPOGRAPHY, GEOLOGY AND SOILS
Under the No Action Alternative, physiography, topography, geology, and soils would remain the
same.
With the Action Alternatives, there will be some ground disturbance associated with the
installation of the transmission water pipelines. However, the environmental effect is anticipated
to be temporary in nature and limited to the physical footprint of disturbance during construction
and the use of heavy machinery.
For the Preferred Alternative 6, surface disturbance related to construction is limited to connecting
Well No. 6 to a power source, and the new small diameter water transmission lines from Well No. 6
to the Well No. 2, and from Well Nos. 3 and 4 to the storage tanks. This will involve removal of
vegetation from either the corridor between Well No. 6 to the Well No. 2 transmission line along the
east water district boundary or along Diamondback Drive and Pomerene Road as an alternative.
Construction of the waterline along the western portion of Diamondback Road and/or along
Pomerene Road would occur within cleared rights-of-way. Removal of vegetation will also occur
along the alignments needed to connect Well No. 3 and Well No. 4 to the storage tanks including
from Well No. 3 to the intersection of W. Pomerene Road and Old Pomerene Road, from Well No.
4 to the that same intersection and then from that intersection to the storage tanks. This includes an
alternative route between Well No. 4 and the storage tanks along Tumbleweed Lane and between
Whiskey Road and Sonora Verde Drive, along Tumbleweed Lane extended to Pomerene Road.
These alignments may cross the Pomerene Canal, an NRHP site, multiple times; however, the
proposed waterline will avoid any impacts by boring under the canal for any crossings.
4.3 WATER RESOURCES
Under the No Action alternative, water resources will remain the same. PDWID will continue to
be out of compliance with Federal and State drinking water quality standards for arsenic and
fluoride.
None of the Action alternatives, including the Preferred Alternative, is anticipated to contribute to
existing or new water quality concerns. Addressing drinking water quality problems is the purpose
of the proposed project; and the proposed project is anticipated to directly improve drinking water
quality in the PDWID public water system.
Surface and Groundwater Hydrology
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Under the No Action alternative, surface and groundwater hydrology will remain the same.
With the Action Alternatives, any changes to the operation of the existing wells will not have an
impact on the San Pedro River, since there is no hydrologic connection. The deep aquifer that
PDWID accesses is confined below a thick clay layer. PDWID Well Nos. 2, 3, 4, 5, and 6 are
screened in this deep aquifer.
PDWID has a total pumping capacity of approximately 450 gpm, including 150 gpm from Well
No. 5. It is noted that Well No. 5 was taken out of operation in 2013. In essence, Well No. 6, with
a pumping capacity of 175 gpm, will replace Well No. 5. This will result in a net pumping capacity
increase of 25 gpm, which is a net five percent increase in PDWID's pumping capacity, which is
not anticipated to negatively impact the groundwater conditions and San Pedro River basin in the
area.
In accordance with the federal National Pollutant Discharge Elimination System (NPDES)
requirements, a Storm Water Pollution Prevention Plan (SWPPP) will be developed to minimize
the potential for the Project to cause adverse effects to existing downstream waters through the
implementation of Best Management Practices. Periodic inspections would occur during
construction activities in accordance with ADEQ requirements. This would minimize stormwater
runoff and negative impacts to downstream waters. The Project will not violate a storm water
permit or a wastewater discharge permit either for construction or on-going operations.
Wetlands
Under the No Action alternative, there will be no direct or indirect impacts to wetlands or waters
of the U.S.
The U.S. Army Corps of Engineers (USACE) administers Section 404 of the Clean Water Act,
governing the placement of dredged or fill material into wetland and other waters of the U.S. With
any of the Action Alternatives, including the Preferred Alternative, it is PDWID's intention to
avoid all aquatic resources. However, if avoidance can't be achieved, PDWID will install the new
drinking water transmission pipelines by boring underneath the aquatic resource feature. New
water transmission pipelines conveying water from the wells to the storage tanks are small
diameter of 6-inches or less.
During detailed final design, the consultant will identify all aquatic resource features in the vicinity
of the new transmission pipeline alignments. The ordinary high water level for each aquatic feature
will be identified and an appropriate feature-specific setback distance(s) established. The setback
will be identified and flagged for construction so as to avoid the discharge of dredge or fill material,
or other pollutant into these aquatic resources. Grading activities will be prohibited within the
setback limits. The pipeline alignments shall observe the setback distances and avoid the discharge
of dredged or fill material into aquatic resources. Directional boring may entail staging but must
observe the established setback distance.
If, for any reason, complexities are encountered during final design and avoidance and/or boring
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cannot be implemented, then a preliminary jurisdictional determination will be prepared and
submitted to the Corps for review and approval. If necessary, authorization under Clean Water
Act (CWA) Section 404 will be obtained to discharge dredge and fill material into waters of the
United States for construction.
Floodplains
The majority of the project area completely avoids the 500-year floodplain; however, one segment
of the eastern option for Alternatives 3-7, would cross a mapped segment of Zone A floodplain.
Although the Preferred Alternative could cross the mapped floodplain, these improvements would
not modify the natural flows of floodwaters, and thus there would be no adverse impacts to the
floodplain.
4.4 VEGETATION
See Section 4.2 Physiography, Topography, Geology and Soils for a description of impacts to
vegetation.
4.5 WILDLIFE RESOURCES
Fish and Wildlife
Under the No Action Alternative, wildlife communities in the general area would not be directly
or indirectly affected because construction would not occur. Operation of the existing on-site
systems would remain the same. Direct and indirect long-term impacts would not occur to wildlife
with the implementation of the No Action Alternative.
It is not anticipated that any direct effects to wildlife communities or loss of wildlife habitat would
occur during construction and operation activities for any of the Action Alternatives. Vegetation
within the project area is generally disturbed. More suitable habitat occurs outside of the project
area.
No fish habitat is within the project area; hence no fish species would be affect by any of the Action
Alternatives.
Threatened and/or Endangered Species
The Endangered Species Act (ESA) manages risks posed to plants, fish, and wildlife, and requires
that federal agencies ensure their actions are not likely to jeopardize the continued existence of
listed threated or endangered species or adversely modify the critical habitat essential to their
survival (16 USC §§1531-1599).
Federally-listed threatened or endangered species (Special-status Species) potentially occurring
within the project area were identified through the Ecological Field Office of the US Fish and
Wildlife Service. A screening analysis was conducted to evaluate the potential for occurrence of
Special-status Species and the presence of proposed or designated critical habitat for the species
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within the project area. Based on the screening analysis, only one of the 13 Special-status Species
evaluated has more than a limited potential to be present within the project area: the Sonoran desert
tortoise. Impact determinations for each species evaluated is provided in the attached Table 1. In
addition, the project area does not occur within proposed or designated critical habitat for any
species.
The No Action alternative would not affect endangered and threatened species because no
construction would not occur.
Implementation of any Action alternatives, including the Preferred Alternative, is not anticipated
to impact any federally-listed species or proposed or designated critical habitat as no federally
listed species are considered to have more than a limited potential to occur in the project area.
The potential for any impacts to the Sonoran desert tortoise (if present) for implementation of the
Action alternatives are limited to temporary construction activities. Habitat for the tortoise within
the project area is marginal. It lacks appropriate shelter sites (rocky slopes, caliche dens, other
hard cover) and records for this species in the vicinity of the project area are sparse. The potential
for occurrence of desert tortoise is considered low and adverse impacts to the Sonoran desert
tortoise are not expected. The Sonoran desert tortoise is currently a candidate for listing and is not
yet afforded protection under the ESA.
Migratory Birds
There will be no impacts to migratory birds from the No Action Alternative.
As for the Action Alternative, impacts from the proposed project are anticipated to be primarily
limited to ground disturbance for installation of new pipeline with potential for limited vegetation
clearance. Certain birds (such as burrowing owl) dwell underground and are particularly
susceptible to impacts resulting from land development and construction. However, considering
the project area is situated in a developed area and includes former agricultural fields where many
such birds are associated, MBTA concerns are generally limited to direct impacts to birds and nests
in trees or shrubs. Considering that a minimal amount of vegetation will be cleared, the potential
for bird nests to be affected by the project is limited.
4.6 CULTURAL RESOURCES
A cultural resources inventory completed for the proposed proj ect identified one new archeological
site, AZ EE:3:255(ASM)—the Pomerene Road network—and two isolated occurrences. Two
previously recorded sites, AZ EE:13:85(ASM)—the Pomerene Canal—and AZ
CC:13:80(ASM)/AZ BB:13:760(ASM)—the Tucson-Apache Transmission Line—are located
within the proposed alignment corridors. The Pomerene Canal is a Historic Property determined
eligible for inclusion in the National Register of Historic Places (NRHP) and it crosses all segments
of the project area. The Tucson-Apache Transmission Line crosses portions of the proposed
corridor; however, this site has been determined ineligible for inclusion in the NRHP. Newly
recorded site, the Pomerene Road network, AZ EE:3:255, is recommended as ineligible for
inclusion in the NRHP.
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No construction activities that have the potential to disturb surf ace/sub surface cultural resources
would occur with the implementation of the No Action Alternative. As a result, cultural resources
would not be affected with the selection of the No Action Alternative.
All Action Alternatives, excluding Alternative 2, will cross the Pomerene Canal, a Historic
Property determined eligible for inclusion in the NRHP.
The Preferred Alternative will avoid determined NRHP-eligible site AZ EE:3:85(ASM), the
Pomerene Canal, by boring under the canal. No heavy equipment and vehicles will used to drive
over the Pomerene Canal during construction. If avoidance is not possible for some unforeseen
reason, an approved Historic Properties Treatment Plan will be developed and implemented to
mitigate any adverse effects to the site.
In accordance with Section 106 of the NHPA, if previously unidentified cultural resources are
discovered during construction, the contractor will stop work immediately at that location and take
all reasonable steps to secure the preservation of those features and the SHPO will be notified.
SHPO will, in turn, notify the appropriate agencies, when needed, to evaluate the significance of
the resource. Additionally, any unearthed discoveries found during construction will be treated in
accordance with Arizona Revised Statutes §41-844 and §41-865.
In October 2014, EPA consulted with the SHPO on the proposed project. SHPO made the
determination that EPA's findings were correct and there would be no impacts to cultural resources
from the proposed project.
4.7 AIR QUALITY
Under the No Action Alternative, construction and operational activities that result in particulate
matter and any emissions would not occur.
The project area is not located in the vicinity of a Nonattainment or Maintenance area.
Construction for the Action Alternatives would result in a temporary increase in emissions from
vehicles and construction equipment and fugitive dust from trenching activities associated with
waterline replacement would occur. After construction activities, vehicle and dust emissions in
the project area would return to pre-construction levels. Minor short-term impacts to air resources
during construction could include fugitive emissions will be produced by earthmoving equipment
and vehicular traffic traveling throughout the construction site.
Any construction that would interrupt normal flow of traffic through, or around the project area
(re-routing, stop-and-go traffic, lower speeds, stalled traffic, and idle engine emissions) would also
increase the emission of carbon monoxide, hydrocarbons and nitrous oxides. Efficient traffic
control measures will effectively control this temporary impact. The use of appropriate
construction best management practices will minimize the generation of dust and fine particulate
matter. Quantities of these emissions will also vary based upon the types and level of activities
occurring during construction and the weather conditions.
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Watering work surfaces where practical and approved by permits would likely be conducted to
control dust. Dust permits would be obtained by contractors. Sufficient water would be applied to
control particulate emissions outside of the permit area. Trenches will be backfilled as soon as
possible to minimize loose dirt on the surface. The Preferred Alternative is not anticipated to
adversely impact air quality in the region.
4.8 NOISE
The No Action Alternative would not result in any increased noise since no construction would
occur with this option.
With the Action Alternatives, construction would occur within a rural area and would be temporary
in nature during construction.
4.9 ENERGY AND NATURAL RESOURCES
The No Action Alternative would not result in any increased use of energy or natural resources.
The Preferred Alternative requires that Well No. 6 be equipped for operation. This includes
providing a permanent source of power to the well site. A new power line is expected to be
constructed by extending existing infrastructure along Diamondback Road to Well No. 6.
Disturbance to equip the well will be limited to the area directly around the well site, power pole and
under the conductor line.
4.10 TRANSPORTATION
The No Action Alternative would not result in any impact to traffic or roadways.
Under the Action Alternatives, traffic control will be managed in accordance with applicable
Cochise County and Arizona Department of Transportation (ADOT) design and construction
standards, including temporary signage requirements.
No road closures are anticipated to be required during construction activities. Traffic flow would
be managed by contractor crew members during construction. Traffic-control signage would be
posted to identify construction areas and controls. Construction would adhere to standard
specifications and any applicable permits will be obtained prior to construction.
4.11 HAZARDOUS MATERIALS
The No Action Alternative and the Action Alternatives would not result in impacts to hazardous
materials.
4.12 SOCIOECONOMICS
The No Action Alternative would not result in impacts to socioeconomic resources. There is
potential for a detrimental impact to result if drinking water quality standards are not met for the
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community.
The proposed upgrades to the PDWID system for the Action Alternatives would not cause any
detrimental impact to the socioeconomic conditions within the project area. There are no specific
impacts on general health or quality of life anticipated to impact the surrounding community. The
proposed project is necessary to support existing potable water, safety, and emergency needs.
Any direct and indirect impacts to the local and regional economy as a result of the Action
Alternatives for new employment opportunities or impacts to the local economy are anticipated to
be negligible and temporary. Increased work force for construction and operation of the proposed
project would be minimal. Any additional traffic during construction is not anticipated to generate
increased income opportunities for commercial facilities in the vicinity. The proposed project
would not cause an increased need for police, fire, medical or other community resources. Traffic
flow would be managed by contractor crew members during project construction. Traffic-control
signage would be posted when needed to identify construction areas.
4.13 ENVIRONMENTAL JUSTICE
There are no environmental justice populations based on race, ethnicity, or low income in the
vicinity, therefore minority and low-income populations would not be impacted by the proposed
project. There are no relevant demographic categories where the analysis population is greater than
the reference populations of Cochise County, Arizona or the State of Arizona.
4.14 SU STAIN ABILITY AND GREENING
Under the Action Alternatives, greenhouse gas emissions and energy consumption will be
minimized to the maximum extent practicable. Under the Preferred Alternative, the useful life of
the arsenic treatment media will be extended by the lead/lag configuration of the treatment vessels
at Well Nos. 2, 3 and 4. The media in the lead vessel can be more fully utilized and completely
spent before being disposed of since the lag vessel will remove any break-through arsenic and
provide a barrier that protects the public from elevated arsenic levels.
4.15 HUMAN HEALTH AND SAFETY
Under the No Action Alternative, federal and state drinking water quality standards within PDWID
would continue not to be consistently met. Under the Action Alternatives, water quality standards
for arsenic and fluoride would be met.
4.16 CUMULATIVE EFFECT
The proposed project provides for upgrades, reliability improvements and water quality
improvements. The existing water system and the water system with the proposed project
improvements are both capable of supplying the existing connections including those connections
not currently in service. The minor increase in system source capacity under the project
accommodates minor infill growth, but does not induce growth.
Cumulative impacts result from the incremental impact of an action when added to other past,
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present, and reasonably foreseeable actions, regardless of what agency or person undertakes such
other actions and are collective over a period of time (40 CFR 1508.7). Since the nature and
limited geographic extent of the project area, we limited our review of past, present, and reasonably
foreseeable future actions that have affected resources in the area including agricultural
development and development within the unincorporated community of Pomerene. Considering
that the increase in well source capacity of the water system will be minimal and that anticipated
growth within the existing community will be through infill development, we do not anticipate
that the project will contribute to significant cumulative impacts.
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