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Section 319
NONPOINT SOURCE PROGRAM SUCCESS STURY
Csolomdv
Better Management of Unpaved Roads and Cattle Grazing Reduces
Sediment Loads
Waterbody Improved
Sediment from unpaved roads and poorly controlled cattle
grazing impaired the assessment unit comprising Colorado's
Box Canyon Creek and its unnamed tributaries. As a result, Colorado added the assess-
ment unit to its 1998 Clean Water Act (CWA) section 303(d) list. The U.S. Forest Service
(USFS) completed a number of watershed restoration projects and changed land manage-
ment practices to address sediment sources. Sediment levels dropped, and Box Canyon
Creek and its unnamed tributaries now attain their designated aquatic life uses. Colorado
determined that this assessment unit is no longer impaired as of 2010.
Problem
The watershed of Box Canyon Creek, a tributary
of the West Mancos River, is entirely within
the San Juan National Forest in southwestern
Colorado's Montezuma County. The watershed
includes approximately 5.8 total stream miles; the
mainstem, which is perennial, is approximately 3
miles long. Sediment from disturbed areas such as
unpaved roads (Figure 1), off-road vehicle use areas,
and livestock grazing areas entered the creek. The
presence of excessive fine sediment prevented the
creek from supporting its cold water class I aquatic
life use designation. Consequently, Colorado added
the assessment unit that includes Box Canyon
Creek and its unnamed tributaries to the 1998 CWA
section 303(d) list of impaired waters.
Colorado completed a total maximum daily load
(TMDL) for Box Canyon Creek in June 2000 with a
goal of restoring the macroinvertebrate community
throughout the mainstem. Three metrics were used
to describe the macroinvertebrate community:
total taxa richness, EPT Index, and EPT:C ratio. The
total taxa richness indicates the diversity of the
macroinvertebrate community and is determined
by counting the total number of different taxonomic
groups (e.g., families, genera or species) within a
sample. The EPT index measures the richness of
genera and species from the three aquatic insect
orders most sensitive to pollution—Ephemeroptera
(mayflies), Plecoptera (stoneflies), and Trichoptera
(caddisflies). A third biological metric used to evalu-
ate stream health is the EPT:C ratio, which com-
pares the number of individuals from the sensitive
Figure 1. Before restoration efforts, unmaintained
forest roads like this one contributed sediment to
the creek.
Ephemeroptera, Plecoptera and Trichoptera (EPT)
orders in the sample to the number of individuals
from the pollution-tolerant family Chironomidae
(e.g., non-biting midges). Streams that have an
EPT:C ratio above 0.5 are considered unimpaired.
The TMDL set two additional water quality targets:
(1) a maximum of 25 percent sediment fines of
8.0 millimeters (mm) or smaller diameter deposited
on the surface of the streambed and (2) a road den-
sity no greater than 1.8 total road miles per square
mile within the 5-square-mile Box Canyon Creek
watershed. The TMDL study found a baseline road
density of 6.9 miles per square mile.

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Project Highlights
After the TMDL was approved, the USFS imple-
mented watershed restoration projects and
changed land management practices to address
sediment sources. Unmaintained native surface
roads used for off-road vehicie use were a primary
source of sediment. Because motorized vehicle use
previously had been unrestricted, the road density
in the watershed included many unauthorized, user-
created and unmaintained recreational use roads.
The Bureau of Land Management (BLM) and USFS
implemented travel management plans for the
surrounding area, specifying which roads would be
added, maintained or closed. Each travel manage-
ment plan outlined travel designations, specifying
what types of vehicles would be permitted on each
designated route and in
what season. Travel man-
agement decisions set
restrictions limiting the
use of motorized vehicles
(including off-road and
four-wheel-drive vehicles)
to designated routes
on roads maintained or
added under the travel
management plans.
Implementation of the
travel management plans
also included permanent-
ly closing and reclaiming
many roads (Figure 2),
Figure 2. Many unpaved roads, such
as this one, were closed to vehicular
traffic and reseeded.
Additional sediment control measures included
better management of permitted livestock grazing.
The specific measures used included reducing the
number of cattle and the duration of grazing, as
well as constructing drift fences (typically of barbed
wire) to guide cattle away from sensitive areas.
Changing grazing practices increased vegetative
cover in the watershed and reduced cattle access
to riparian areas, thereby reducing the potential for
accelerated erosion from grazing.
Results
In July 2006 the U.S. Environmental Protection
Agency (USEPA) Region 8, the Colorado
Department of Public Health and Environment
(CDPHE), and the USFS partnered to collect
post-restoration data on substrate particle size,
macroinvertebrate community, stream habitat and
water chemistry at four sites in the BoxCanyon
Creek watershed. The data showed that the TMDL
target for fine sediment—a maximum of 25 percent
fines of 8.0 mm or smaller diameter—had not been
achieved in any of the four reaches of Box Canyon
Creek; however, efforts to meet the TMDL goal for
macroinvertebrate diversity (Table 1) and the target
for road density had been successful.
The data showed a macroinvertebrate community
with a greater richness of species, specifically the
more sensitive EPT species, throughout the entire
stream length than before the project began. The
EPT:C ratio for all reaches was above the target of
0.5, and therefore ail four reaches could be consid-
ered unimpaired.
Table 1. Macroinvertebrate Survey* in Box
Canyon Creek (July 11-12, 2006)

Reach 1
Reach 2
Reach 3
Reach 4
Total Taxa Richness
44
34
34
30
EPT Richness
20
17
11
11
Chironomids (%)
15.14
6.45
9.6
18.43
EPT (%)
75.03
80.82
27.90
53.40
EPTC ratio
0.83
0.93
0/74
0.74
* Streams with an EPT:C ratio above 0.5 are considered unimpaired.
Post-project road density was calculated in
September 2006 using field verification of the exist-
ing geographic information system (GIS) roads layer.
The total length of open roads (system, secondary
system and non-system roads) was 5.689 miles,
and the total watershed area was 4.64 square
miles. These figures gave a current road density of
1.23 miles of road per square mile, well below the
initial density of 6.9 miles per square mile in 2000.
Because of these results, the Colorado Water
Quality Control Commission reports that Box
Canyon Creek fully meets its aquatic life designated
use and is no longer impaired as of 2010.
Partners
Restoration partners included the USFS, in con-
junction with livestock grazing permittees and the
off-road recreation community in the Box Canyon
watershed. BLM and USFS developed travel man-
agement plans for watershed areas. USFS, USEPA
Region 8, and the CDPHE's Water Quality Control
Division conducted post-restoration monitoring
and documented watershed improvements using
approximately $15,000 in federal funding; CDPHE
and USEPA Region 8 personnel provided additional
in-kind assistance.
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-11-001M
February 2011
For additional information contact:
Joan Carlson
USFS Rocky Mountain Region
jycarlson@fs.fed.us • 303-275-5097

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