Cottonwood Creek
Preliminary Assessment
John Lhotak, Jeff Dunn, Victoria Edwards, Michael Sanctuary,
Gary Hughes, Matt Vitale
University of Montana, Environmental Studies
Table of Contents
Purpose – to describe the current condition of Cottonwood Creek
Overview of approach/objectives
Natural history – climate, soils, hydrology, vegetation
Land-use – mining, logging, grazing
Proposed Conservation and Restoration Projects
Current condition of riparian area
Likely value of the conservation efforts
Recommendation for future study and for landowner monitoring
Appendix A – RWRP Lotic Health Summary
Appendix D – Assessment Polygons Map
Appendix F – RWRP Lotic Health Assessment Field Score Sheet
Appendix G – DEQ Stream Reach Assessment Form
Appendix I – Polygon Cross Sections
Introduction
Purpose – to describe the current condition of Cottonwood Creek
With guidance and financial assistance from the Natural Resource Conservation Service (NRCS), ranch owners in the Cottonwood Creek watershed, a tributary to the Upper Clark Fork of the Columbia River, will be implementing land and water conservation strategies and stream restoration projects in the summer of 2001. These strategies and projects include grazing management plans, removal of water gaps along the creek, and planting of riparian vegetation. The NRCS will be receiving some funds from the Environmental Quality Incentives Program to assist the landowners in carrying out their projects.
There is limited information on the current health of the Cottonwood Creek. It is the purpose of this study to assess the current health and characterize the landscape of Cottonwood Creek. The information gathered in this study can then be used to assess the benefits of the conservation and restoration activities.
Background on EQIP
The Environmental Quality Incentives Program (EQIP) was established in the 1996 Farm Bill (www.nrcs.usda.gov). EQIP is designed to provide technical, monetary and educational assistance to ranchers and farmers who wish to address soil erosion, water quality and related natural resource concerns. Fifty percent of the money in the EQIP fund goes toward livestock-related conservation practices. The conservation and restoration projects in this study are partially funded by EQIP, which provides up to a 75% cost share. In addition, all work perform under EQIP is done on a voluntary basis.
Overview of approach/objectives
The objectives of this study include:
1. To assess the current condition (“health”) of Cottonwood Creek’s riparian areas.
2. To provide baseline data needed to evaluate the benefits of conservation and restoration projects.
3. To gather information about the current and historical land-uses in the Cottonwood Creek Watershed.
4. To make recommendations on a landowner monitoring system.
As a result of time limits, the health assessment component of this study focused on the lower section of the creek’s watershed. This is the portion of the creek in which the conservation and restoration projects will be implemented. The health assessment was done using the University of Montana’s Riparian and Wetland Research Program’s Lotic Inventory Form. Information about the current and historical land-uses was gathered on a watershed scale.
Organization of Report
First, this paper will discuss the study design and approach used to gather information about Cottonwood Creek. Second, it will present and discuss the findings of field work and information gathering. Third, the paper will provide comments on the creek’s use support, the probable value of conservation efforts, and other areas of concern for the watershed. Lastly, the paper will make recommendations for further study and fot the components of a landowner monitoring system.
Study Design and Approach
To characterize the watershed of Cottonwood Creek, six graduate students from the University of Montana’s Environmental Studies Watershed Heath Clinic gathered information from existing sources and collected field data during 6 weeks in the fall of 2000.
Existing sources of data
Information about the planned conservation and restoration projects was gathered from Susan Sakay of the NRCS. In addition, Ms. Sakay supplied aerial photographs, U.S.G.S. topographic maps, and soil maps of the watershed. Aerial photographs were used to divide the study area into relatively homogenous sub-areas (polygons) which were then assessed. Aerial and topographic maps aided in classifying the creeks using the Rosgen (1996) method. A Rosgen classification was determined because the system is recognized throughout the land management community. The soil maps provided information on the general soil make up of the riparian assessment area.
Information about climate, geology and historical landuse in the watershed was researched at the William K Kohrs Library in Deer Lodge, MT.
Additional information on current landuse and topographic maps was gathered from the Montana State Library’s National Resource Inventory Service (NRIS) web page, http://www.nris.state.mt.us. The information gathered from NRIS was in digital format compatible with the geographic information system program ArcView. Information downloaded from the NRIS web site included digital topographic maps, current landuse, streams, and state political boundaries. This information, along with field data, was used to generate maps of the watershed using ArcView GIS.
Field work data
Riparian condition assessments were conducted along the
creek using the University of Montana’s Riparian and Wetland Research Program’s
(RWRP) Lotic Health Assessment Field Sheet.
Description of this protocol and examples of the field sheets are
available on their web site at http://www.rwrp.umt.edu. A copy of the assessment form used is also
in Appendix F. This assessment system
was chosen because it has been tested in many Northern Rockies states and
Canada since 1992 (Thompson et al. 1998)
Also, it has been designed to be relatively quick to complete and to be
used as a rough filter to identify sites that need further attention.
In addition to the
RWRP’s assessment method, information about the riparian area was gathered
using the Montana Department of Environmental Quality’s (DEQ) Stream Reach
Assessment Field Form. Description of
this protocol and examples of the field sheets are also available online at http://www.deq.state.mt.us/ppa/
mdm/index.htm. A copy of this
assessment form is also in Appendix G.
This assessment method was compared to the RWRP assessment method. These two methods are similar in their focus
on riparian habitat but differ somewhat in what they assess and how they score
each area. Table 1 lists the factors
assessed by each method.
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Table
1 – factors assessed by RWRP and DEQ |
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DEQ |
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Time constraints restricted
our riparian assessments to the parts of Cottonwood Creek and Reese Anderson
Creek that included NRCS conservation and restoration projects.
Both assessment
methods divide the riparian area into polygons (homogenous sub-units) then
assess each separately. Our study area
was divided into a total of 15 polygons, 11 on Cottonwood Creek and 4 on Reese
Anderson Creek. (See Appendix D for polygon map) The DEQ assessment method only applies to second, third and
fourth order streams, therefore does not apply to Reese Anderson Creek (a first
order stream).
Upstream and
downstream boundaries of each polygon were recorded using a Magellan 315 GPS
unit. This was done so that the
locations can be found in the future.
In addition, these points were downloaded into the program Map Site
2.0. The points were then transferred
to ArcView GIS, and maps were created showing the location of the
polygons. The GIS information from the
NRIS web site was used as a base map.
Our sites were photo
documented using a Olympus
Digital Camera D-460 Zoom, 1.3 Megapixel. Photographs were taken looking
upstream and downstream at the boundaries between each polygon
Stream cross
sections were measured at about the middle of each polygon, and locations
recorded using the Magellan 315 GPS unit.
Measurements taken at these locations include bank full width and depth
and base flow width and depth. Depth
was measured once every meter along the stream cross section. The measurements were taken to calculate a
width to depth ratio along the stream.
Rosgen (1996) states that a measurement of the width to depth ratio is
one of the basic assessment measures of a stream channel’s condition. However, these measurements were only taken
on Cottonwood Creek and the one polygon assessed on Baggs Creek. Reese Anderson Creek has a restricted flow
because of a dam in its upper reaches and was just a trickle at the time of
measurement. However, Reese Anderson Creek
was visually assessed for downcutting in the RWRP and DEQ assessment methods.
Stream discharge was measured using a standard Price Pygmy Meter at four locations along Cottonwood Creek. (See map in Appendix C) The six-tenths method was used to calculate discharges. That is, flow was measured 6/10 of the way from the water surface to the stream bed because this is the point in the water column that usually exhibits average water velocities. Measurements were taken at three locations on October 20th. After discussing the first set of measurements, we decided to add a sample point farther upstream on November 3rd and drop one of the previously sampled locations. Discharge measurements were taken to determine whether the creek was gaining or losing water.
Findings and Discussion
Creek Description
Cottonwood Creek, located in Powell County, MT, is a tributary to the upper Clark Fork of the Columbia River (see maps, appendix B and C). Cottonwood Creek joins the Clark Fork River at the northern edge of the town of Deer Lodge, Montana. The headwaters of Cottonwood Creek are in the Beaverhead – Deerlodge National Forest east of Deer Lodge. In the national forest, the creek has three branches, south, middle and north branches. Down on the valley floor Cottonwood Creek has two tributaries, Baggs Creek and Reese Anderson Creek. These two creeks join Cottonwood Creek in the ranch land east of Deer Lodge. In total, the watershed drains about 42.8 square miles of land.
Natural history – climate, soils, hydrology, vegetation
The Cottonwood Creek watershed is in a semiarid environment. The average annual precipitation is 12 to 14 inches, half of which falls during the months of May, June, and July (Nimick et al. 1993).
The watershed includes mountains terrain dropping to a valley underlain by Tertiary and Quaternary sedimentary deposits. The groundwater in the valley is shallow, has a high flow rate and a high infiltration rate. Transmissivity of alluvium in the watershed is 970 feet squared per day and in bedrock 130 feet squared per day. The median well depth in the area is 37 feet, with few wells deeper than 70 feet. (Nimick et al. 1993)
We focused on the soil of the lower watershed floodplain. Most soils in this area are loam types. Much of the soil is alluvium and is more than 60 inches deep, resulting in thick deposits. The range of water capacity for the soils in the riparian area is 5.05 to 6.2 inches. Soil slopes range from 0 to 8% in the floodplain and 8 to 15% along the riparian edge. A few soils in the upper lands have slopes of 15 to 60%. (NRCS 2000) See Appendix H for further soil description.
In 1831 W.A. Ferris provided the first European description of the Deer Lodge Valley, stating that the streams in the valley had “groves and thickets of Aspen, Birch and Willow, and occasional clusters of currant and gooseberry bushes” (Courchene 1989). Today, the general vegetative makeup of the watershed includes mature Populus trichocarpa (black cottonwood) stands and Populus tremuloides (quacking aspen) groves in the lower watershed riparian areas. Second growth Pinus contorta (lodgepole pine) forests exist in the upper watershed, and upland vegetation in the lower watershed is comprised of herbaceous vegetation used for grazing.
Land-use – mining, logging, grazing
Stock raising, homesteading, ranching, and farming began in the Deer Lodge Valley in the 1870’s. By 1890, mining was a major activity in the Deer Lodge Valley with some mines located in the upper Cottonwood Creek watershed. The most recent mining activity in the watershed was the Emery Mine which ended mining in 1950. However, the mine operation did not have any water rights. Today, the main uses in the watershed include logging, ranching, crop and pasture, recreation, and urban areas. The map in Appendix E shows the general landuse in the watershed.
Rosgen classification
Using the Rosgen (1996) classification system, Cottonwood Creek is classified as a B3 stream. B refers to the stream type and 3 refers to the makeup of the streambed material. B type streams are moderately entrenched, have a moderate slope and are riffle dominated with infrequently spaced pools. Rosgen (1996) describes the substrate category 3 as being predominantly cobbles with lesser amounts of boulders, gravel and sand. All these characteristics are evident in Cottonwood Creek. Other characteristics of a B3 stream include a sinuosity of greater than 1.2, a slope between .02 and .04, and a width to depth ratio at bankfull of greater than 12. Cottonwood Creek from Baggs Creek to Interstate 90 has a sinuosity of 1.2, a slope of .02, and an average width to depth ratio of 18.
Reese Anderson Creek is classified as an A4 stream using Rosgen’s (1996) system. A4 streams are described as steep, deeply entrenched and confined, and the channel is incised in coarse depositional materials. Cattle use and water restriction has caused Reese Anderson Creek to have a silty creek bed.
Stream Discharge
In this study, discharge measurements were taken to evaluate stream flow losses and gains along the channel. Table 1 shows the results of the discharge measurements. Polygon C-2 is at the upstream end of the riparian assessment area and polygon C-11 is located at the downstream end of the riparian assessment area, right before the stream flows under the highway. The sample location in C-10 is located in one of the water gaps that will be removed in the summer of 2001. After the first set of samples, we did not take second measurement at C-10 because the location being heavily impacted by cattle activity. Also we felt that a sample location should be added further upstream from C-2 before the creek’s water gets diverted. This sample site is located just downstream of the confluence of the south fork of the creek – the last fork to join the main stem. See map in Appendix C for measurement locations.
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Table 1: Computed discharge measurements |
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Date |
Polygon |
Q (m³/s) |
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10/20/2000 |
C-2 upstream |
0.214 |
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C-10 |
0.0712 |
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C-11 downstream |
0.114 |
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11/03/2000 |
Upper Cottonwood Creek |
0.254 |
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C-2 |
0.0268 |
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C-11 |
0.0989 |
One of the project sites (a water gap removal) located in polygon C-10 had heavy erosion with corrals directly in the stream. Such an impacted site has the potential for significant groundwater / surface water interactions (Allan, 1995). The results of discharge measurements taken on 10/20 might indicate there is some groundwater / surface water interactions taking place.
The higher discharge recorded at the upper creek site and the lower discharge recorded at C-11 indicates that the creek is losing water as water flows downstream. This would be consistent with the number of diversions along the lower portions of the creek. At least five diversions were noticed between C-1 and C-11. There is an irrigation diversion just downstream from the C-10 site. This could be the cause of the higher discharge recorded at C-11 relative to C-10 on 10/20. The higher discharge at C-11 from C-2 recorded on 11/03 in relation to the discharges recorded on 10/20 might indicate that some diversions were closed off or that some groundwater recharge is occurring.
It is important to keep in mind that these fall baseflow measurements were made during a very low flow year for the Deer Lodge valley. We recommend that discharge be determined at these sites along with some additional sites and diversions during the spring.
Stream Cross Sections
The stream’s cross section was measured at about the middle of each polygon in polygons C1 to C9. Polygons C10 and C11 were measured at the beginning and end of the polygon because this is the proposed site of one of the conservation / restoration projects (water gap removal). Graphs of these measurements are in Appendix I.
Figure 1 illustrates the relationship of the bankfull widths and the fall baseflow widths. Upstream of polygon C9, baseflow width closely tracks the bankfull width. C1 is located on Baggs Creek which was not flowing at the time. The difference between baseflow and bankfull width increase downstream. This could be the result of ground water-surface water interaction, dewatering, and/or grazing activities. The bankfull width drops at C11L because the creek has been armored to align the creek with the culvert going under the highway.
Figure 1
Figure 2 shows the width to depth ratio of Cottonwood Creek from polygon C1 to C11. Rosgen (1996) states that as the width to depth ratio increases the hydraulic stress increases, accelerating bank erosion. This causes the stream to continue to widen. The ratio also illustrates a widening trend downstream from polygon C1; as the ratio increases, the stream becomes wider and more shallow. There is a noticeable drop in the width to depth ratio in polygon C6 because the creek banks in C6 are well stabilized by willows. In polygons C10U to C11L, the greater the width to depth ratio may be due to grazing and the herbaceous-dominated understory.
Figure 2
Proposed Conservation and Restoration Projects
There are three conservation and restoration projects planned for the spring of 2001. See map in Appendix D for locations. Project site one includes removing water gaps from the creek, fencing off a 30 foot riparian buffer, and providing an offstream water source for cattle.
Project site two involves fencing off ponds created by dams in the creek channel. Once the ponds are fenced off, riparian vegetation will be planted and an additional pond will be created upstream of the first two. This additional pond is to act as a sediment trap for the two downstream ponds.
The third project site is a grazing management plan and the construction of three fences perpendicular to Baggs Creek. The fences will result in 3 separate pastures. One pasture will be grazed while the other two are rested. Cattle will not be restricted from the riparian area.
Current condition of riparian area
Riparian and Wetland Research Program’s (RWRP) Lotic
Health Assessment Field Sheet
Of the 15 polygons assessed using the RWRP Lotic Health Assessment, five were found to be functioning but at risk, and the remaining ten polygons were found to be non-functioning systems. See Appendix A for a summary table of the RWRP assessment forms. The major concerns along the riparian areas include overgrazing, dewatering and invasive plants. All but 3 polygons are dominated by mature Populus trichocarpa (black cottonwood) stands. Most of the undergrowth in these stands has been grazed over and little, if any, P. trichocarpa (black cottonwood) regeneration is occurring. This is especially the case in Polygons C9, C10 and C11.
Polygon
C4
Two polygons are classified as P. trichocarpa / Cornus
stolonifera (black cottonwood / red-osier dogwood) community type, C4 and
C7. This mid-seral stage community type
is characterized by an overstory of cottonwoods and a potentially dense
understory of diverse shrubs and herbaceous vegetation (Hansen et al. 1995). This community type provides excellent
wildlife habitat and helps support fish communities by providing thermal cover,
debris recruitment and streambank stability (Hansen et al. 1995). C. stolonifera (red-osier dogwood) is
a highly palatable plant to livestock and is the first affected by grazing
(Hansen et al. 1995). The
classification system used will classify an area as a P. trichocarpa / C.
stolonifera (black cottonwood / red-osier dogwood) community even when C.
stolonifera (red-osier dogwood) occurs in only 1% of the polygon. This is the case with polygon C4 (rated as
non-functioning). There is a remnant
stand of C. stolonifera (red-osier dogwood) which has been protected
from grazing by down trees. If it were
not for this stand, polygon C4 would be classified as a P. trichocarpa /
Herbaceous (black cottonwood / Herbaceous) community type.
Polygon
C11
Six polygons, C1, C5, C9, C10, C11 and R2, were classified as
a P. trichocarpa / Herbaceous (black cottonwood / Herbaceous) community
type. This community type represents a
severely disturbed P. trichocarpa / C. stolonifera (black cottonwood /
red-osier dogwood) community type. A
common disturbance comes from heavy grazing – which is evident in the area
(Hansen
et al. 1995). Two other polygons, R3
and R4, are classified as P. trichocarpa / Symphoricarpos occidentalis
(black cottonwood / western snowberry) which is also a disturbance indicator
community type of P. trichocarpa / C. stolonifera (Hansen et al.
1995). Depending on amount of
disturbance allowed in the future, this community type can also become a P.
trichocarpa / Herbaceous community type where the cottonwood stand will
open up and result in a drier site (Hansen et al. 1995). When a stand reaches this stage, it can be
difficult to revegetate with desired woody plant species because the canopy may
to open and/or the water table may have been lowered (Hansen et al. 1995). All polygons classified as P. trichocarpa
/ Herbaceous (black cottonwood / Herbaceous) or P. trichocarpa / S.
occidentalis (black cottonwood / western snowberry) rated as
non-functioning.
Polygon
C11
Other habitat and communities types found in the assessment area include Juniperus scopulorum / C. stolonifera (rocky mountain juniper / red-osier dogwood) habitat type (polygon C2), Populus tremuloides / C. stolonifera (quacking aspen / red-osier dogwood) habitat type (polygon C3 and C8), and Salix lutea / Carex rostrata (yellow willow / beaked sedge) habitat type (polygon C6). These four polygons are considered functional but at risk. These polygons are at risk because of such problems as invasive species in polygon C6, moderate grazing in polygon C8, down cutting of the stream in polygon C2, and road building through the creek in polygon C3.
Polygon
C6
Montana Department of Environmental Quality’s (DEQ) Stream Reach Assessment Field Form
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Table 2 |
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RWRP
Form Overall
Score |
Descriptive Category |
Polygon |
DEQ
Form Overall
Score |
Rating |
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57.89 |
Non-functioning |
C1 |
0.68 |
Moderate impairment |
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78.95 |
Functional At Risk |
C2 |
0.71 |
Minor impairment |
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61.40 |
Functional At Risk |
C3 |
0.62 |
Moderate impairment |
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35.09 |
Non-functioning |
C4 |
0.68 |
Moderate impairment |
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42.11 |
Non-functioning |
C5 |
0.53 |
Severe impairment |
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70.18 |
Functional At Risk |
C6 |
0.68 |
Moderate impairment |
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71.93 |
Functional At Risk |
C7 |
0.64 |
Moderate impairment |
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70.18 |
Functional At Risk |
C8 |
0.70 |
Moderate impairment |
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40.35 |
Non-functioning |
C9 |
0.65 |
Moderate impairment |
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35.09 |
Non-functioning |
C10 |
0.64 |
Moderate impairment |
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17.54 |
Non-functioning |
C11 |
0.58 |
Moderate impairment |
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14.29 |
Non-functioning |
R1 |
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Form does not apply |
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35.09 |
Non-functioning |
R2 |
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Form does not apply |
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42.11 |
Non-functioning |
R3 |
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Form does not apply |
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54.39 |
Non-functioning |
R4 |
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Form does not apply |
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RWRP scoring: 80 – 100
Proper Function Condition (healthy) 60 – 79
Functional At Risk (healthy but with problems) <60 Nonfunctional (unhealthy) |
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DEQ
scoring: 87-100 Non-impaired
(full support) 80-86
Non-impaired but Threatened (full support) 71-79
Minor impairment (partial support) 55-70
Moderate impairment (partial support) 0-54
severe impairment (non-support) |
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A comparison of the results from the RWRP assessment method and the DEQ assessment method are shown in Table 2. The RWRP rating and DEQ ratings are fairly comparably except for polygons C9, C10 and C11. For the purposes of this study, we felt that the RWRP assessment presents a more realistic picture of the condition present in the Cottonwood Creek watershed. This in part because the assessment team received training in the RWRP assessment method but not in the DEQ assessment method. Moreover, the DEQ assessment method does not look as closely at vegetation components in the riparian area as the RWRP assessment method. The DEQ assessment method seems to be more appropriate to use with a larger stream.
Discussion and Conclusion
Use Support
Cottonwood Creek is used for agriculture and probably helps recharge private drinking water wells. In 1988, Montana Fish Wildlife and Parks (nris.state.mt.us/wis/Mris) found westslope cutthroat trout, brown trout, brook trout and slimy sclupin in Cottonwood Creek. During this study’s field work, fish were sighted in the creek, but the species were not identified. So we can not say if Cottonwood Creek still supports a cold water fishery.
Likely value of the conservation efforts
The
removal of the watergaps along the creek and fencing off a 30 foot riparian
buffer will have a positive effect for the creek (Ehrhart and Hansen
1998). Providing a riparian buffer will
reduce nutrients entering the creek.
Since site one is a Populus trichocarpa / Herbaceous (black
cottonwood / Herbaceous) community type, there may be problems with
revegetation of the riparian zone if the water table has been lower
drastically. However, it is possible
the water table has not dropped significantly since the general geology of the
area has a higher water table (Nimick et al. 1993). If revegetation is successful, woody species along the creek will
help to control the widening of the creek, help with bank building, and provide
fish habitat (Ehrhart and Hansen 1998).
Site Two
Fencing
off the constructed ponds on Reese Anderson Creek and planting riparian
vegetation should improve water quality in the ponds. However, with the dams still in place, flow will still be
restricted downstream. There is no
evidence of flooding occurring below the ponds. Populus trichocarpa (black cottonwood) requires the fresh
soil deposits left by flooding for regeneration (Hansen et al. 1995). The stand of black cottonwood present will
eventually become decadent and likely will not regenerate (Hansen et al. 1995).
Site Three
Our assessment of Baggs Creek is insufficient to proved much evidence for commenting on the possible benefits of fencing and a grazing management plan. However, limiting the length cattle will be in a pasture will have a positive affect (Ehrhart and Hansen 1998). There is still debate on what the best management strategy is but there is a consensus that the length of time the animals spend in an area can be a significant factor in the health of a site (Ehrhart and Hansen 1998). Also, the use of upland attractors, ie. off stream water and mineral blocks, will help disperse cattle within each pasture, reducing the pressure on the riparian areas (Ehrhart and Hansen 1998).
Other problematic sites
Downstream of the ponds on Reese Anderson Creek, cattle are allowed to graze in the riparian area. This is the major cause of the poor health scores. Polygons R4 and R3 still have shrubs species in them but Symphoricarpos occidentalis (western snowberry) is an indicator of a degraded site. A grazing management plan limiting cattle use of the riparian area could help maintain woody vegetation along the creek and improve the health of Reese Anderson Creek below the ponds and keep.
The riparian area above project site one (polygons C9 and C10) might benefit from a grazing plan. However, with these areas already severely disturbed, resulting in a Populus trichocarpa / Herbaceous (black cottonwood / Herbaceous) community type, it would take an intensive management plan to return woody species to the riparian area (Hansen et al. 1995). Such a plan would probably included excluding grazing from the area with no guarantee of success of woody species revegetation because the water table may have been lowered and the cottonwoods now shade the underrstory(Hansen et al. 1995).
Recommendation for future study and for landowner monitoring
We recommend 1) extending this riparian corridor assessment upstream of polygon C1 along Baggs Creek and along Cottonwood Creek to the where the creek forks. 2) analyzing stream nutrient levels upstream and downstream of water gaps to assess the benefit of the watergap removal. This analysis can also help determine if a 30 foot buffer will be wide enough to help reduce nutrients entering the creek from the corrals which will remain next to the buffer area.
As far as landowner monitoring, we recommend 1) use of the RWRP short form. The use of this form could be taught in a one day workshop. Most of the questions on the form are straight forward and would require only a little training. The bulk of the education needed to use the form is likely to be teaching plant communities types. 2) continued measurement and photo documentation of the creek’s cross section. Creek profile monitoring will determine if the creek is widening or narrowing. Photo documentation provides an excellent visual assessment of the riparian area throughout the years.
Acknowledgments
This study was conducted by a group of six graduate students which includes Victoria Edwards, Gary Hughes, Jeff Dunn, Michael Sanctuary, Matt Vitale, and myself. Dr. Vicki Watson at the University of Montana and Susan Sakay at the Natural Resource Conservation Service in Deer Lodge, Montana, offered guidance to the group. Thanks to all these people and to all the landowners involved in restoration efforts in the Cottonwood Creek watershed.
Literature Cited
Allan, David J. 1995. Stream Ecology: structure and function of sunning waters: New York, Chapman and Hall, 399 pp.
Courchene, D. Ed 1989. Powell County: Where it all Began. Powell County Museum & Arts Foundation, Historic Action Committee. Deer Lodge.
Ehrhart, Robert C., Paul L. Hansen 1998. Successful Strategies for Grazing Cattle in Riparian Zones. Montana BLM Riparian Technical Bulletin No. 4, USDI Bureau of Land Management, Montana State Office. 47pp.
Hansen, P. L., R. D. Pfister, K. Boggs, B. J. Cook, J. Cook, J. Joy, and D. K. Hinckley 1995. Classification and management of Montana’s Riparian and Wetland Sites. Montana Forest and Conservation Experiment Station, Missoula, MT., 646 pp.
Nimick, David A., Tom Brooks, Kent A. Dodge, and L. K. Tuck 1993. Hydrology and Water Chemistry of Shallow Aquifers Along the Upper Clark Fork, Western Montana: (Prepared in cooperation with the Montana Bureau of Mines and Geology) Helena, Montana, U.S. Geological Survey Water Resources Investigation Report 93-4052, 62 pp.
Natural Resource Conservation Service, 2000. Soil Maps of Powell County, MT: Deer Lodge, MT, 4 maps, scale 1:24,000.
Rosgen, Dave 1996. Applied River Morphology. Printed Media Companies, Lakewood, CO.
Thompson, William H., Robert C. Ehrhart, Paul L. Hansen, Thomas G. Parker, and William C. Haglan. 1998. Assessing Health of a Riparian Site. Montana Riparian and Wetland Research Program, U. of Montana, Missoula, MT.
USDA Conservation Programs. Environmental Quality Incentives Program. Publication date not posted. Nov. 25, 2000. <http://www.nrcs.usda.gov/NRCSProg.html>
Department of Environmental Quality. Monitoring and Data Management Bureau Nov. 2000. Nov. 25, 2000. <http://www.deq.state.mt.us/ppa/mdm/index.htm>
Montana Fish Wildlife and Parks. Montana River Information System. Publication date not posted. Nov. 25, 2000. http://nris.state.mt.us/wis/Mris/FullReport2.asp?SppR=on&MgtR=on&BarrR=on&RtgR=on&PopR=on&DewR=on&ProtR=on&Spawn=on&FlowR=on&LandR=on&GenetR=on&LWuseR=on&PresR=on&ChannR=on&RefR=on&Inst=72838&Cmd=View+on+Screen
Appendix A – RWRP Lotic Health Summary
Vegetative Score is determined from question 1 to 6. Soil/ Hydrologic Score is determined from questions 7 to 11. See sample score sheet in Appendix F. Problem Summary includes field observations and the question number in which the polygon scored in the lower third, ie. if a possible 6 points for the question the polygon scored a 2.
|
Polygon |
Dominance Type |
Habitat Type - Community Type |
Vegetative
Score |
Soil/Hydrologic
Score |
Overall Rating |
Descriptive Category |
Problem Summary |
|
C-1 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Herbaceous (black cottonwood /Herbaceous) |
33.33 |
80.00 |
57.89 |
Non-functioning |
Dewatered
/ Channelized 2-3-4-5-7 |
|
C-2 |
Pseudotsuga menziesii
(douglas fir) |
Juniperus scopulorum /
Cornus stolonifera (rocky mountain juniper / red-osier dogwood) |
74.07 |
83.33 |
78.95 |
Functional At Risk |
Downcutting 3 |
|
C-3 |
Populus trichocarpa (black
cottonwood) |
Populus tremuloides /
Cornus stolonifera (quacking aspen / red-osier dogwood) |
40.74 |
80.00 |
61.40 |
Functional At Risk |
Road
through stream 2-4-5-8 |
|
C-4 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Cornus stolonifera (black cottonwood / red-osier dogwood) |
29.63 |
40.00 |
35.09 |
Non-functioning |
Removed
riparian forest 1-2-3-4-7-8-9 |
|
C-5 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa / Herbaceous
(black cottonwood / Herbaceous) |
29.63 |
53.33 |
42.11 |
Non-functioning |
Stream
runs through pasture 2-3-4-5-7-8-9-10 |
|
C-6 |
Yellow Willow |
Salix lutea / Carex
rostrata (yellow willow / beaked sedge) |
44.44 |
93.33 |
70.18 |
Functional At Risk |
Willows
are stabilizing banks – knapweed colonized gravel beds 2-3-4 |
|
C-7 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Cornus stolonifera (black cottonwood / red-osier dogwood) |
66.67 |
76.67 |
71.93 |
Functional At Risk |
“Moderately
grazed” 2-3-7 |
|
C-8 |
Populus trichocarpa (black
cottonwood) |
Populus tremuloides /
Cornus stolonifera (quacking aspen / red-osier dogwood) |
66.67 |
73.33 |
70.18 |
Functional At Risk |
“Moderately
grazed” 2-3-7 |
|
C-9 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Herbaceous (black cottonwood / Herbaceous) |
25.93 |
53.33 |
40.35 |
Non-functioning |
only
Cottonwoods and grass 2-3-4-5-7-9 |
|
C-10 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Herbaceous (black cottonwood / Herbaceous) |
44.44 |
26.67 |
35.09 |
Non-functioning |
Water
gaps – better shrubs than polygon 9 1-2-3-5-7-8-9 |
|
C-11 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa / Herbaceous
(black cottonwood / Herbaceous) |
18.52 |
16.67 |
17.54 |
Non-functioning |
Creek
banks armored Young
cottonwoods 1-2-3-4-5-7-8-9-11 |
|
R-1 |
herbaceous |
na |
14.29 |
14.29 |
14.29 |
Non-functioning |
Earth
dams across creek to create ponds 1-2-3-4-7-8-9-10 |
|
R-2 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Herbaceous (black cottonwood / Herbaceous) |
40.74 |
30.00 |
35.09 |
Non-functioning |
Ponds
holding back most of water. Cows
grazing in riparian area. 2-3-4-5-7-8-9-10 |
|
R-3 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Symphoricarpos occidentalis (black cottonwood / western snowberry) |
44.44 |
40.00 |
42.11 |
Non-functioning |
Knapweed
on facing uplands 2-3-4-5-7-9-10 |
|
R-4 |
Populus trichocarpa (black
cottonwood) |
Populus trichocarpa /
Symphoricarpos occidentalis (black cottonwood / western snowberry) |
62.96 |
46.67 |
54.39 |
Non-functioning |
Downcutting Some
aspen and junipers – heavy browsing on low branches 2-3-5-9-10 |
Polygon C1 starts where the road crosses over Baggs
Creek and ends at the confluence of Baggs Creek and Cottonwood Creek. Baggs Creek was dewatered in this
section. Cottonwood Creek flowed through
a low gradient ditch, with a silty bottom, before the confluence with Baggs
Creek. The polygon contained a Populus
trichocarpa/ Herbaceous (black cottonwood/ Herbaceous) community type and
had a Populus trichocarpa (black cottonwood) dominance type. This is a disclimax plant community type
occurring on heavily disturbed sites and characterized by an overstory of
widely spaced cottonwoods and an understory containing grasses (Hansen, et
al,1995).
Polygon C2 starts at the confluence of Baggs Creek
and Cottonwood Creek where a headgate diverts a portion of the stream into an
irrigation ditch that contained three miner’s inches of water in early
October. The polygon ends where a fence
crosses the river. The polygon is
relatively undisturbed, since access was restricted by the irrigation ditch and
steep bank on river right (facing downstream) and a fence on river left. A steep gradient below the confluence has
caused the channel to be downcut. This
polygon contains a Juniperus scopulorum/ Cornus stolonifera (Rocky
Mountain juniper/ red-osier dogwood) habitat type with a Pseudotsuga
menziesii (Douglas fir) dominance type.
This habitat type can occur when the Populus trichocarpa/ Cornus
stolonifera (black cottonwood/ red-osier dogwood) community type becomes
dewatered, due to a lowering water table, and begins to convert to an upland
site (Hansen, et al, 1995).
Polygon C3 starts where a fence crosses the river
and ends where the riparian vegetation has been removed on river left. There are a couple of places were heavy
equipment have been driven through the stream, presumably for construction of
the new house on the hill. This site is
occupied by a Populus tremuloides/ Cornus stolonifera (quaking aspen/
red-osier dogwood) habitat type and a Populus trichocarpa (black
cottonwood) dominance type. This
habitat type contains an overstory of Populus tremuloides(quaking aspen)
and a dense understory of shrubs, including Cornus stolonifera (red
osier dogwood), Alnus incana (mountain alder), Rosa woodsii (woods
rose) and Symphoricarpos occidentalis (western snowberry) (Hansen, et
al, 1995).
Polygon C4 starts where the riparian vegetation was
removed on river left and ends where Reese Anderson Creek joined Cottonwood
Creek. This polygon was on a highly
developed piece of land containing a house, several corrals, and a newly built
pond. Cottonwood Creek ran through a
fenced grazing pasture that was devoid of woody vegetation. Below the corral the stream contains a large
growth of aquatic macrophytes, starting a trend which continues through polygon
C11. This polygon contains a Populus
trichocarpa/ Cornus stolonifera (black cottonwood/ red-osier dogwood)
community type and a Populus trichocarpa (black cottonwood) dominance
type. Cornus stolonifera
(red-osier dogwood) individuals are primarily isolated to a small area that is
protected from grazing by a large pile of logs. The lower section of the polygon, in which the corrals are found,
more closely resembles the Populus trichocarpa/ Herbaceous (black cottonwood/
Herbaceous) community type.
Polygon C5 starts at the confluence of Reese
Anderson Creek and ends where two fences cross the steam. A fence runs along the stream creating an
area that appears to be used as a riparian pasture. Some areas of the stream bank are steep and vegetated, while
other areas have clearly been trampled by livestock. Extensive pugging and hummocking was visible in between the two
fences.
Polygon C6 starts below the two fences and continues
until the end of the dense willows.
This area has a dense cover of willows.
Bare areas recently exposed to flooding were being colonized primarily
by knapweed. This site contains a Salix
lutea/ Carex rostrata (yellow willow/ beaked sedge) habitat type and a
Populus trichocarpa (black cottonwood) dominance type. This habitat type is found in places where
the water table remains near the soil surface throughout the summer (Hansen, et
al, 1995).
Polygon C7 begins at the end of the dense willows
and ends where a road to access the power lines crosses the stream. This site contains a Populus trichocarpa/
Symphoricarpos occidentalis (black cottonwood/ western snowberry) community
type and had a Populus trichocarpa (black cottonwood) dominance
type. This community type occurs when a
Populus trichocarpa/ Cornus stolonifera (black cottonwood/
red-osier dogwood) community type has been moderately disturbed (Hansen et.
al., p.260). Moderate levels of grazing
and browsing reduce the abundance of Cornus stolonifera (red-osier
dogwood) and increase the abundance of Symphoricarpos occidentalis
(western snowberry) and Rosa woodsii (woods rose) (Hansen et al,
1995). A dense stand of Populous
tremuloides (quaking aspen) has colonized the interface between the
riparian zone and the uplands along the right side of the river in this
polygon.
Polygon C8 begins where the power line road crosses
the creek and ends at the upper fence line of the Burt property. The health score of this polygon was 71%,
which is considered to be functional at risk.
This site contains a Populus tremuloides/ Cornus stolonifera
(quaking aspen/ red-osier dogwood) habitat type and a Populus trichocarpa
(black cottonwood) dominance type.
Polygon C9 begins at the fence line along the upper
end of the Burt property and ends were a log spans the creek contiguous with a
fence. Most of the riparian vegetation
has been removed from this site leaving a stand of mature cottonwoods. This site appears to be used as a riparian
pasture. A large pasture separated from
the stream by a fence was actively being used for grazing.
Polygon C10 begins where a fence abuts up to a log across the stream and ends where a fence crosses the creek at the bottom of the Burt property. It is in this polygon that the conservation project is to be conducted. The upper end of this polygon contains a braided channel that has a stand of young cottonwoods growing on a gravel bar. A fence, which separates the corrals from the stream, has been built into the stream at three different places creating water gaps used to water the livestock. The streambank has been flattened at each of the water gaps. A corral at the bottom of the polygon, with two fences crossing the river, allows livestock free access to the stream. Riparian vegetation has been remove inside the corrals, while the fenced off portions between the water gaps has provided protection for the stream banks and riparian vegetation
Polygon
C11 begins below the last corral on the Burt property and ends were the creek
goes through two culverts under the road.
This site has been severely impacted.
The stream channel, which was widened by flooding, has been mechanically
dredged, narrowed and straightened to confine the flow before it heads into the
culverts under the road. Young
cottonwoods are growing in the gravelly substrate along this altered
channel. A long section along the right
side of the stream above the culverts has been reinforced with rip-rap. Texas longhorns were actively grazing in
this polygon.
Polygon R1 is the uppermost study site on Reese
Anderson Creek. It begins at the fence
above the ponds and continues to the first fence below the ponds. It currently contains two ponds. The upper pond has been filled in with
sediments and is dry, while the lower pond contains water. Only herbaceous vegetation is growing in
this polygon.
Polygon R2 begins at the fence below the ponds and
continues to the next fence. Livestock
have free access to this section, causing pugging and hummocking to be
widespread. Knapweed is abundant on the
south facing slope rising from the stream in this polygon, as well as in
polygons R3 and R4.
Polygon R3 extends down to the next fence. This site contains a Populus trichocarpa/
Herbaceous (black cottonwood/ Herbaceous) community type and a Populus
trichocarpa (black cottonwood) dominance type.
Polygon R4 extends down to the confluence with Cottonwood Creek. There was a small wetland located within this polygon. This site contains a Populus trichocarpa/ Herbaceous (black cottonwood/ Herbaceous) community type and a Populus trichocarpa dominance type. Populus tremuloides is also abundant in this polygon.
