117.121-27–22.
science for a changing World -
Prepared in cooperation with the U.S. FOREST SERVICE
Data Summary and Loading Sources for Selected Water-Quality
Characteristics of Streams in BlowdOWn Areas, North Fork
Elk River Watershed, Colorado, March 1999–August 2000
ABSTRACT the selected constituents from the five water-quality sampling
sites.
On October 25, 1997, in and around the Routt National For-
est and the Mount Zirkel Wilderness Area, a winter Snowstorm
occurred in conjunction with heavy winds that resulted in the INTRODUCTION
destruction of thousands of acres of old-growth tree stands. The
U.S. Geological Survey, in cooperation with the U.S. Forest Ser- On October 25, 1997, in and around the Routt National
vice, collected water-quality data at five sites in the North Fork Forest and the Mount Zirkel Wilderness Area, a winter Snow-
Elk River watershed where most of the blowdown occurred. In storm occurred in conjunction with heavy winds that resulted in
this report, these data are used to characterize water quality in the destruction of thousands of acres of old-growth tree stands
areas affected by the blowdown compared to that of relatively (fig. 1). Maximum wind velocities of 120 miles per hour were
undisturbed areas. No difference was detected between loads of recorded. This event, typically referred to as a "blowdown," is
106050 106045. 106040 106935' 106930'
| |
LOCATION MAP
40955
Study area
40°50'
EXPLANATION
Blowdown and salvage
logging zone
Mount Zirkel Wilderness Area
Routt National Forest
Lake
Secondary or logging road
Improved road or highway
40945 Water-quality sampling site
Private land SUDOCS
O 2 MILES
H-H COLLECTION
Figure 1. Water-quality sampling sites and area affected by blowdown in the North Fork Elk River watershed.
D
D
~ Stream
Q
A
c
N
U.S. Department of the Interior
U.S. Geological Survey January 2003
FS–127–02



considered to be an anomaly usually associated with hurricane-
force winds. The abundance of old-growth canopy such as Engel-
mann spruce and subalpine fir in the region indicates the rarity of
this type of event in this area (Snook, 1999).
Trees over a large area were uprooted, which disrupted the
air-soil interface (fig. 2). As a result, the potential for increased
sediment yield and mass wasting increased. Increases in sediment
yield have been linked to issues concerning stream and forest hab-
itat, floodwater conveyance, and stream-chemistry imbalance
(Elliott and DeFeyter, 1986). Disturbance from salvage logging
may increase sediment yield and affect stream chemistry; how-
ever, disturbance from salvage logging likely will occur on a
smaller scale relative to the disturbance from blowdown.
The U.S. Geological Survey (USGS), in cooperation with the
U.S. Forest Service, collected water-quality data at sites in the
North Fork Elk River watershed where most of the blowdown
occurred. In this report, these data are used to characterize water
quality in areas affected by the blowdown compared to that of rel-
atively undisturbed areas.
SITE SELECTION AND DATA COLLECTION
Water-quality sampling sites (fig. 1, table 1) were selected to
represent undisturbed, disturbed, and salvage-logging zones.
Water-quality samples were collected and concurrent streamflow
measurements made at each site from March 1999 to August
2000. All water-quality and streamflow data were collected using
USGS quality-assurance protocols (Wilde and Radtke, 1998;
Rantz and others, 1982). Water-quality samples were analyzed for
field parameters, major ions, dissolved nutrients, total phospho-
rus, total and dissolved metals, suspended sediment, and turbidity.
The farthest upstream sampling site, on the North Fork Elk River
just upstream from Agnes Creek (site 1), was chosen as a back-
Figure 2. Routt National Forest near North Fork Elk River after the
blowdown of October 25, 1997.
Table 1. Sample collection site in North Fork Elk River watershed
[mi”, square miles; USGS, U.S. Geological Survey]
Site USGS station - Drainage
number number Site name area
(fig. 1) (mi”)
North Fork Elk River above 12.3
Agnes Creek near Clark
North Fork Elk River above 19.3
Trail Creek near Clark
Lost Dog Creek above 3.2
mouth near Clark
1 405057106451000
2 40495.01.06462700
3 40475106454200
4 404727.106453700 English Creek above mouth 2.5
near Clark
North Fork Elk River above 41.4
mouth near Clark
5 404620106461900
ground site because blowdown was minimal in this subwatershed,
and the site is upstream from a salvage-logging area. Site 2 was
located on the North Fork Elk River upstream from the conflu-
ence with Trail Creek. The watershed for site 1 represents less
blowdown than site 2. Both sites are upstream from where sal-
vage logging is done. Igneous and metamorphic rocks underlie
the watershed upstream from site 1. The geology that underlies
site 1 continues into the watershed of site 2 and includes uncon-
solidated Pleistocene deposits and, to a limited extent, Mancos
Shale (Tweto, 1979). The next two sites are on tributaries of the
North Fork Elk River, Lost Dog Creek (site 3) and English Creek
(site 4). Sites 3 and 4 were subjected to some of the heaviest
blowdown outside of the Mount Zirkel Wilderness Area and rep-
resent basins where salvage logging is being done. The underly-
ing geology in these basins is similar to that upstream from site 2
with the addition of some sandstone and limestone (Tweto, 1979).
North Fork Elk River above mouth near Clark (site 5) is an inte-
grator site for the entire watershed. Comparison of water-quality
information from site 5 with water-quality information from sites
2, 3, and 4 characterizes water quality in the area affected by the
blowdown and salvage logging and provides perspective on the
water quality of tributary inflows from the west side of the water-
shed.
DATA SUMMARY
Summary statistics for field parameters, chemical constitu-
ents, and physical parameters are listed in table 2. All water-
quality and streamflow data collected for this study are published
in USGS annual data reports for Colorado (U.S. Geological Sur-
vey, 1999 and 2000). The Elk River and tributaries to the Elk
River, including streams located within the Mount Zirkel Wilder-
ness Area, are classified as “outstanding waters” by the State of
Colorado and carry Aquatic-Use Class 1 and Recreation 1 desig-
nations (Colorado Department of Public Health and Environment,
2001).

Physical Parameters
Summary statistics for physical parameters are listed in
table 2. These parameters are streamflow, suspended sediment,
and turbidity. There are no State standards for suspended sedi-
ment or turbidity. However, comparison of suspended-sediment
concentrations and turbidity between sites would indicate if
there were any differences upstream from the major disturbance
areas as compared to those measured downstream near the
mouth of the North Fork Elk River. Suspended-sediment con-
centrations at site 1 ranged from less than 1 to 10 milligrams per
liter and median concentration was 2.5 milligrams per liter. Sus-
pended-sediment concentrations at site 5 ranged from less than 1
to 21 milligrams per liter and median concentration was 2 milli-
grams per liter. Ranges of concentration and median concentra-
tions for suspended sediment were similar at sites 2, 3, and 4.
The similarity of suspended-sediment concentrations between
sites upstream and downstream from the areas in the watershed
affected by the blowdown indicates that there was no measurable
effect of the blowdown on suspended-sediment concentrations.
Turbidity values measured at sites 1 through 5 also were similar.
Field Parameters
Field measurements were for dissolved oxygen, pH, spe-
cific conductance, and water temperature. Comparisons of sum-
mary statistics for each parameter at individual sites are listed in
table 2. These data indicate that all values of dissolved oxygen or
pH were in compliance with State instream standards. The State
of Colorado Department of Public Health and Environment does
not set standards for specific conductance or temperature for the
North Fork Elk River watershed. Comparisons of the median
specific-conductance values and water temperature values from
the primarily undisturbed area (site 1) to those measured near
the mouth of the North Fork Elk River downstream from water-
sheds that contained areas of blowdown (site 5) indicate that spe-
cific conductance and water temperature are similar at all sites.
Chemical Constituents
Chemical constituents such as major ions, nutrients, and
trace elements can originate from a variety of sources. The ways
in which solutes occur in natural waters are influenced by many
environmental factors, especially climate, underlying geology,
and biochemical effects associated with life cycles of plants and
animals (Hem, 1985). Because there is minimal human impact *
on the watershed of the North Fork Elk River, water-quality con-
stituents are derived primarily from natural sources.
Except for dissolved solids and aluminum, chemical constitu-
ents listed in table 2 have instream standards set by the State of
Colorado. All constituents sampled at all sites had concentrations
less than the instream standard. Based on the comparison of
median concentrations for constituents listed in table 2, water qual-
ity among sites is similar. For example, at sites 1 through 5,
median concentrations of total phosphorus ranged from less than
0.004 to 0.007 milligram per liter.
LOADING SOURCES
Constituent concentrations and field-parameter values were
similar among all sampling sites; however, constituent loading (the
product of streamflow, constituent concentration, and a coefficient)
could be affected by surface disturbance associated with the blow-
down in a particular subbasin. To evaluate constituent loading
among the five sampling sites, constituent loading per square mile
was calculated for selected constituents at each site to determine if
any particular subbasin contributed more loading per unit area than
other subbasins. Median constituent loads per square mile for dis-
solved nitrite plus nitrate, total phosphorus, dissolved zinc, dis-
solved solids, and suspended sediment were computed (table 3).
Because constituent concentration among sites is a function
of runoff and drainage-basin area, analysis of loading between sites
may be useful. Except for nitrite plus nitrate and dissolved zinc,
Lost Dog Creek (site 3) had the largest median load for the selected
constituents. Median dissolved nitrite plus nitrate and dissolved
zinc loads decreased from upstream to downstream on the main
stem of the North Fork Elk River (sites 1, 2, and 5, table 3).
Loads for dissolved nitrite plus nitrate, total phosphorus, dis-
solved zinc, dissolved solids, and suspended sediment for the five
water-quality sampling sites were compared using analysis of vari-
ance (ANOVA) (SPSS Inc., 1997). For the purpose of this analysis
the data were ranked, and ANOVA was done on the ranks of the
data (Conover and Iman, 1981). The grouped means of ranked data
for the selected constituent loads among the five sites were not sig-
nificantly different (p > 0.05). The study shows that there was no
difference between loads of the selected constituents from the five
water-quality sampling sites; therefore, the conclusion can be made
that constituent loads from watersheds with large areas of blow-
down and where salvage logging occurred were not different from
loads in areas where minimal blowdown and no salvage logging
occurred. -

Table 2. Selected streamflow and water-quality data for sites located in North Fork Elk River study area
[ft’ſs, cubic feet per second; mg/L, milligrams per liter, SC, specific conductance, NO2 + NO3, nitrite plus nitrate; p.S/cm, microsiemens per centimeter: “C, degrees Celsius; pg/L, micrograms per liter;
N, number of samples; NTU, nephelometric turbidity units; 3, less than]
Physical parameters - Field parameters Chemical constituents
instan- Oxvden H water Sulfate, '. * Phos- . i. Copper, Iron, Silver, Zinc, Dis-
Summary taneous suspended .......... *** * dis- .* phorus, "...'" .."” dis- dis- dis- dis-
statistics Turbidity dis- stan- SC tempera- dis- dis- dis- solved
stream- sediment solved total solved solved solved solved .
flow (mg/L) (NTU) solved dard (us/cm) ture (mg/L as solved (mg/L as solved solved (ug/L as (ug/L as (ug/L as (ug/L as solids
3 (mg/L) units (°Celsius) (mg/L as 9 (ug/L as (ug/L as |19 |19 |l |l (ug/L)
(ft”/s) SO4) P) Cu) Fe) Ag) Zn)
N) Al) Co)
North Fork Elk River above Agnes Creek
(site 1)
N 11 10 11 11 11 11 11 11 11 11 6 6 6 6 6 6 11
Median 11 2.5 0.5 8.9 7.2 35 5 1.6 0.08 <0.008 44.5 <1 <1 24 <0.60 <20 23.1
Maximum 218 10 2 10.9 7.5 43 11.6 4.5 0.18 0.01 51 <1 1 46 <1.0 <20 36.1
Minimum 0.62 <1 0.3 7.9 6.6 21 0.5 1.1 0.05 <0.004 9 <1 <1 20 <0.20 <20 16.0
North Fork Elk River above Trail Creek
(site 2)
N 11 9 11 11 11 11 11 11 11 11 7 6 6 6 6 6 11
Median 21 2 0.7 8.9 7.2 39 6.6 1.6 0.06 <0.004 24.0 <1 0.75 35 <0.60 <20 26.7
Maximum 282 79 2 11.3 7.8 52 14 2.9 0.14 0.034 60.6 <1 1 82 <1.0 <20 39.0
Minimum 5.9 <1 0.4 7.7 6.9 21 0.1 1.1 0.03 <0.004 <15 <1 <1 20 <0.20 <20 16.0
- Lost Dog Creek
(site 3)
N 11 11 11 11 11 11 11 11 11 11 6 6. 6 6 6 6 7
Median 9.1 2 - 0.7 10.1 7.4 35 3.5 1 0.033 0.006 61.3 <1 <1 - 78 <0.60 <20 28.0
Maximum 41 10 8 11 7.8 44 10.5 1.3 0.120 0.010 78.1 <1 5 130 <1.0 <20 37.0
Minimum 2.2 <1 0.3 7.9 6.9 21 0.1 0.7 <0.005 <0.008 29.0 <1 <1 50 <0.20 <20 18.0
- - English Creek
(site 4) *
N 11 11 11 11 11 11 11 11 11 11 6 6 6 6 6 6 . 11
Median 5 1 0.6 9.2 7.2 33 3.4 1.1 0.011 0.007 62.3 <1 <1 76.5 <0.60 <20 31.0
Maximum 26 9 2.4 10.6 7.6 39 10.9 1.4 0.093 0.010 75.6 <1 3 150 <1.0 <20 36.7
Minimum 1.2 <1 0.3 7.8 6.8 19 0.2 0.7 <0.005 <0.004 34 <1 <1 51 <0.20 <20 17.5
North Fork Elk River above Mouth
(site 5) - -
N 11 11 11 11 11 11 11 11 11 11 6 6 6 6 6 6 11
Median 44 - 2 0.6 9.8 7.5 54 3.9 2.5 0.033 0.007 40.8 <1 <1 55 : 30.60 <20 38.0
Maximum 422 21 9 10.6 7.9 74 15.7 4.9 0.101 0.021 67.9 <1 <1 79 <1.0 <20 49.0
Minimum 16 <1 0.2 7.4 7.1 24 0 1.1 0.013 <0.004 12.0 <1 <1 30 <0.20 <20 19.1

Table 3. Median load for selected constituents per square mile of drainage area
[NO2 + NO3, nitrite plus nitrate; Ib/d/mi”, pounds per day per square mile]
Site name NO2 + NO3, Phos- Zinc, Dissolved Suspended
(fig.1) dissolved phorus, total dissolved solids sediment
9- (Ib/d/mi2) (Ib/d/mi”) (Ib/d/mi”) (Ib/d/mi2) (Ib/d/mi”)
North Fork Elk River above Agnes Creek near Clark 0.60 0.02 0.49 186 12
North Fork Elk River above Trail Creek near Clark 0.32 0.02 0.53 222 12
Lost Dog Creek above mouth near Clark 0.60 0.09 0.45 465 33
English Creek above mouth near Clark 0.12 0.07 0.36 360 9.6
North Fork Elk River above mouth near Clark 0.25 0.04 0.35 169 4.9
REFERENCES
Colorado Department of Public Health and Environment, 2001,
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River Basin and North Platte River: Water Quality Control
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and estimated annual suspended-sediment loads: U.S.
Geological Survey Water-Resources Investigations Report
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Web site URL: http://www.fsl.noaa.gov/~vondaust/f299/
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SPSS Inc., 1997, SYSTAT 7.0—Statistics: Chicago, User's guide,
751 p.
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(reprinted).
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U.S. Geological Survey Water-Data Reports CO–99–2
through CO—00–2.
Wilde, F.D., and Radtke, D.B., 1998, National field manual for col-
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variously paged.
—Kenneth J. Leib and Paul von Guerard

For more information about this study, write to:
Subdistrict Chief
764 Horizon Drive
Room 125
Grand Junction, CO 81506
email: kileib Gusgs.gov
email: pbvongue Ousgs.gov
UNIVERSITY OF MICHHGAN
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