,'qN Section 319
NONPIINT SOURCE PRIGUM SUCCESS STORY
TVew7 Mexico
Mine Reclamation Improves Willow Creek Water Quality
Waterbody Improved Willow Creek was buried by waste materials from the Pecos/
Tererro Mine at the confluence of Willow Creek and the Pecos
River. In the early 1990s, the New Mexico Environment Department (NMED) found elevated
turbidity conductivity, sedimentation, and metals (including cadmium and zinc) in the creek.
These findings led NMED to add Willow Creek to the state's Clean Water Act (CWA) section
303(d) list of impaired waters for turbidity, conductivity, and stream bottom deposits (now
called sedimentation) in 1998. Cadmium and zinc were added as additional causes of
impairment in 2002. Around the year 2000, stakeholders began restoring mined areas, and
water quality improved. As a result. New Mexico removed Willow Creek from its list of
impaired waters for turbidity in 2004 and for cadmium and zinc in 2012.
Problem
The 5.26-mile-long Willow Creek is a tributary
to the Upper Pecos River in north-central New
Mexico (Figure 1). The creek's watershed is
largely managed by the Santa Fe National Forest
(92 percent), but it also includes some private
land (8 percent) and a mine site owned by the
New Mexico Department of Game and Fish. The
watershed is 98 percent forested and 2 percent
grassland.
In the early 1900s, waste rock generated from
operations at the Pecos/Terrero mine and mill was
deposited into Willow Creek and its floodplain. The
fill forced the creek from its original channel and
caused it to flow over waste rock deposits along
the southern edge of the floodplain. The mine and
mill waste rock was also used for decades as con-
struction and maintenance material for local roads
and in the nearby state fish hatchery and camp-
ground. Initial environmental impact investigations
indicated that runoff and leachate from these waste
materials had contaminated ground water, surface
water, soil, and sediment downstream.
After a large fish kill occurred during the spring
of 1991, NMED conducted a water quality survey
and found metals in seeps and surface water
discharges around the mine. As a result, NMED
placed Willow Creek on the state's CWA section
303(d) list of impaired waters in 1998 for turbidity,
conductivity, and stream bottom deposits, and in
2002 for cadmium and zinc.
Figure 1. Willow Creek is in New Mexico's
Upper Pecos River watershed (blue).
Project Highlights
Restoration efforts date back to 1950, when the
New Mexico State Game Commission purchased
all properties related to the mine and mill. In 1985
NMED (at that time known as the New Mexico
Environmental Improvement Division) conducted
a comprehensive investigation of the area in
conjunction with Cyprus-Amax Minerals Company
staff. An Administrative Order on Consent was
issued in 1992; it required the responsible party,
Cyprus-Amax, to reclaim the mine site (including

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Willow Creek and surrounding areas). The
reclamation work, conducted from 1999 through
2003, included closure of the mine shaft, excavation
and consolidation of all mine waste, revegetation
of disturbed areas, and geomorphic restoration of
the Willow Creek floodplain, wetlands, and riparian
habitat. The geomorphic restoration, implemented
using Rosgen natural design methods, was
completed in 2000. it included removing nearly
65,000 cubic yards of waste rock from the
floodplain and reconstructing 900 feet of the creek
(Figure 2).
Results
m
Figure 2. Project partners removed waste rock from the
floodplain and restored the natural channel along Wiilow
Creek, seen here in July 2008,
Willow Creek: Exceedances of Water Quality Criteria

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2001 2010	2001 2010
Cadmium	Zinc
1998 2004
Turbidity
Figure 3. The number of exceedances of the water
quality criteria for metals and turbidity decreased
following the restoration of Willow Creek.
The mine reclamation project improved water
quality. Turbidity data collected in 2004 showed
that only one of eight samples exceeded 10
nephelometric turbidity units, allowing NMED to
remove turbidity as a cause of impairment on the
state's 2004 CWA section 303(d) list (Figure 3)
Water quality data collected in 2010 showed that
Willow Creek met the state water quality standards
for dissolved cadmium and zinc. All 50 water quality
samples taken throughout the year showed that
cadmium and zinc were below detection iimits, with
the exception of one zinc sample of 40 micrograms
per liter (/jg/L), which although detectable, was still
below the zinc water quality criterion. The criteria
for metals are dependent on hardness and can
vary over time; however, between 2001 and 2010
the mean cadmium concentration dropped from
7.75 /Jg/L to 0 jjg/L (all samples below detection)
and the zinc concentration dropped from 4.65/Jg/L
to 0.3yg/L. Therefore, NMED removed cadmium
and zinc from the 2012 CWA section 303(d)
list as sources of impairments to Wiilow Creek
(NM-2214.A _ 030). The 5.26-miie-long creek
remains listed as impaired for sediment/siltation
and specific conductance.
Partners and Funding
Cyprus-Amax Minerals Company, the primary
responsible party, conducted the reclamation
work. (Cyprus-Amax was later purchased by Phelps
Dodge.) Additional responsible parties included
the New Mexico Department of Transportation and
the New Mexico Department of Game and Fish
because they had used contaminated materials on
state roads and on Lisboa Springs Fish Hatchery
property, respectively. Two NMED bureaus were
involved: The Ground Water Quality Bureau pro-
vided oversight of reclamation and monitoring,
and the Surface Water Quality Bureau conducted
surface water quality monitoring. CWA section
319-funded staff assisted in designing the recon-
structed channel. In addition, the consulting firm
Daniel B. Stevens & Associates conducted water
quality monitoring.
PRO^°
2
o
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA xxx-xx-xxxx
August 2014
For additional information contact:
Daniel Guevara, New Mexico Environment
Department, Surface Water Quality Bureau
505-476-3086 • daniel.guevara@state.nm.us
David L. Mayerson, New Mexico Environment
Department, Ground Water Quality Bureau
505-476-3777 • david.rnayerson@state.nm.us

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