%
NONPOINT SOIREE SICCESS STOIY
Riparian Restoration Efforts Reduce Temperature and Sedimentation,
Improving Polvadera Creek
WatPfhnrlv Imnrnvprl
VVdlUIUUUy iplUVUU
Off"road vehicle usa9e' rangeland grazing and a loss of riparian
habitat contributed to increased temperature and sedimentation
which degraded water quality in New Mexico's Polvadera Creek. As a result, Polvadera Creek was
added to the Clean Water Act (CWA) section 303(d) list of impaired waters for temperature in 2000
and sedimentation in 2006. Following a CWA section 319 project with the Santa Fe National Forest
(SFNF), which included riparian restoration practices such as native vegetation plantings and riparian
livestock exclusion devices, water quality in Polvadera Creek improved. Due to these improvements,
the segment was removed from the 2014 list of impaired waters for sedimentation and temperature.
Problem
Polvadera Creek (segment NM-2116.A _ 011) is in
northern New Mexico near the town of Abiquiu
(Figure 1). The creek flows north from its headwa-
ters in the Jemez Mountains to its confluence with
Cahones Creek, which flows into Abiquiu Reservoir
on the Rio Chama in the Rio Grande Basin. The
watershed is primarily in the SFNF; the main land
use is rangeland grazing.
Water quality surveys as far back as 1996 and 1999
revealed that 14 miles of Polvadera Creek (from its
headwaters to the confluence with Cahones Creek)
were impaired by excess sediment and high tem-
peratures. These impairments prevented Polvadera
Creek from meeting its designated use of high
quality co/dwateraquatic life and resulted in the
listing of the creek for stream bottom deposits in
1998 and temperature impairment in 2000. Stream
bottom deposits were delisted as an impairment
in 2004 based on the assessment protocol at that
time; however, in 2006 the stream was re-assessed
using the current protocols, and it was listed as
being impaired by sedimentation once again. To
meet standards for sedimentation, the creek has to
comply with the narrative standard, which requires
it to be free of fine sediment that would clog the
natural substrate. To meet standards for tempera-
ture, the maximum stream temperature must be
less than 23°C (73°F), and it cannot exceed 20°C
for longer than four hours on three consecutive
days (4T3). In 2004 the New Mexico Environment
Department developed a total maximum daily load
(TMDL) to address the temperature impairment on
Polvadera Creek.
NM-2116JL011
NHD FLow line
^H Watershed Area
Figure 1. The Polvadera Creek watershed is in
northern New Mexico.
Project Highlights
In 2009 the SFNF began a CWA section 319
restoration project to remove the temperature and
sedimentation impairments in Polvadera Creek.
The project had six major components:
1. Riparian vegetation treatment. Beginning in
2007, SFNF staff removed encroaching juniper
bushes and planted willows. The treatment is
credited with minimizing the impact of the 2010
South Fork Fire on the riparian corridor.
-------
Figure 2. SFNF staff installed this steel pipe fence
to prevent ATVs from accessing and damaging the
riparian corridor in a recreation area.
2. Closing the stream corridor to all-terrain vehi-
cles (ATV). SFNF staff constructed the primary
barrier of rocks and steel pipe fencing in 2009,
and it successfully reduced erosion and sedimen-
tation from ATV use (Figure 2). Maintenance is
ongoing because vandalism has occurred.
3. Beaver re-introduction. The project area his-
torically supported a robust beaver population,
which had helped to create and maintain a sig-
nificant wetland complex. The wetlands trapped
sediment and increased baseflow, offering a buf-
fer against high summer stream temperatures.
Beaver re-introduction was planned but not
carried out because of opposition by area farm-
ers and ranchers; however, beavers reappeared
in the project area on their own. With continued
improvement of riparian habitat, the beaver popu-
lation is likely to increase.
4. Riparian fencing. The riparian fence was con-
structed in 2001 and continues to be maintained.
In 2009 an additional 0.5 miles of fence was
added to the riparian fence to further protect the
creek. Post-fire flooding has required significant
maintenance work on the fence.
5. Grazing allotment management. A National
Environmental Policy Act (NEPA) analysis was
completed for the Polvadera Grazing Allotment in
2009, which resulted in the authorization of graz-
ing under an Adaptive Management approach.
This approach included actions such as the
deferral of grazing in Rio Grande Cutthroat Trout
areas until after July 15th and the installation of
upland alternative water sources for livestock
called "trick tanks." Completed in 2011 and 2012,
these alternative water sources reduce grazing
pressure in the riparian areas (Figure 3).
6. Community education. In 2009 the SFNF
teamed up with Santa Fe Youthworks, a
Figure 3. This completed livestock "trick tank," an
alternative water source installed in an upland area,
reduces grazing pressure on the riparian corridor.
nonprofit community organization that helps
disconnected youth and families in northern
New Mexico become engaged in community
service. Youthworks and SFNF staff conducted
two workshops on constructing fencing and
fish habitat structures, as well as a workshop on
careers in the Forest Service.
Results
Monitoring in 2012 revealed water quality improve-
ments in Polvadera Creek. There were 30.5 percent
sand and fines, which was above the 20 percent
threshold for Mountain Site Class. However, the log
Relative Bed Stability (LRBS) was -0.63, which is
lower in absolute value than the threshold of -1.1 for
Mountain Site Class. This indicated that although
there was greater sand and fines, sufficient sedi-
ment transport capacity existed to protect aquatic
life. In addition, the maximum thermograph tempera-
ture was 20°C, which met the standard. Therefore, in
2014 sedimentation and temperature were removed
as causes of impairment for Polvadera Creek. The
vegetation treatment was credited with prevent-
ing greater damage to the riparian corridor from
the 2010 South Fork Fire. Deferring grazing helped
protect the native Rio Grande Cutthroat Trout fishery.
Partners and Funding
The improvement in water quality in Polvadera
Creek was the result of a collaboration between
multiple partners. The SFNF, the primary coopera-
tor, was responsible for implementing the project
using $41,000 of CWA section 319 funding. Santa
Fe Youthworks provided education and outreach.
Lastly, Polvadera Grazing Allotment permittees sup-
ported the restoration by modifying their grazing
activities due to the aforementioned NEPA analysis.
Ui
o
U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA841-F-15-001QQ
October 2015
For additional information contact:
Daniel Guevara
New Mexico Environment Department, Surface
Water Quality Bureau
505-476-3086 • daniel.guevara@state.nm.us
------- |