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| Deep Creek Watershed and Spawning Enhancement Project |
Broadwater County, Montana |
Primary Project Type: Instream Restoration
Secondary Type: Instream Restoration |
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Reach 11, site 36, July 1997... |
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Primary Problem: Bank Instability
Secondary Problem: Flow Alteration, Sedimentation |
| Main Restoration Action(s): Bioengineering, Flow management, Indirect bank stabilization, Sediment control |
| Native Fish Focus: N/A |
Is this project part of a watershed scale restoration? No
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| Project Dates: 1991 to 2001 |
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Initial Monitoring: 1991 to 1993
Restoration Implementation: 1996 to 1999
Follow-up Monitoring: 1997 to 2001 |
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Lead Agency:
Montana Department of Environmental Quality
Broadwater Conservation District
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| Project Partners: |
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| Project Location:
Deep Creek originates in the Big Belt Mountains east of Townsend, Montana and flows 24 miles west to its confluence with the Missouri River just south of Townsend. The Deep Creek project area encompasses the lower 19.3 miles of the stream. The project area is split into 11 individual stream reaches primarily defined by roads or property lines. Click here for a map of the reaches. Reach lengths vary from 0.68 to 5.34 miles. Reach numbers begin at the mouth of Deep Creek and continue upstream, ending at the point where U.S. Highway 12 crosses the stream.
Click here for a map of the project area.
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Project Description:
Deep Creek is one of the few tributaries to the Missouri River between Toston Dam and Canyon Ferry Reservoir that provides spawning and rearing habitat for rainbow and brown trout migrating out of the Missouri River and Canyon Ferry. Deep Creek also supports a resident trout population, particularly in the upper reaches. Approximately 20 private landowners control the majority of the lands in the project area. Agriculture (grazing, irrigated and dryland cropping) is the predominant land use in the area.
Monitoring conducted from 1991 - 93 indicated that Deep Creek was impaired due to excessive sedimentation, dewatering, and elevated water temperature. These problems were related to bank erosion, loss of riparian vegetation, and irrigation withdrawals. Deep Creek subsequently was listed as “impaired” by the Montana Department of Environmental Quality. It was not fully supporting the designated beneficial uses for cold water aquatic life, including fish and aquatic insects. In 1996 a plan was formulated to address the problems of sedimentation, dewatering, and elevated water temperature. This plan, called a Total Maximum Daily Load (TMDL), identified the problems, recommended solutions, and established targets to achieve full support of beneficial uses. Several strategies were used to implement the plan, including extensive bank and channel stabilization to reduce sedimentation, reestablishing riparian vegetation, improved irrigation, and alterations in riparian management. |
| Project Goals: The primary goals of the project are to: 1) remove Deep Creek from Montana Department of Environmental Quality’s list of impaired streams, 2) promote recovery of stream and channel stability and riparian vegetation in Deep Creek to reduce sediment delivery from eroding banks, 3) enhance trout spawning success in Deep Creek, 4) provide information and guidance on lower-cost stream stabilization and erosion control measures to landowners. |
| Project Methods:
Assessment and design was completed for seven reaches of highest priority in terms of area of eroding banks and sediment contribution to the stream or areas contiguous to high priority reaches with the best potential fish habitat. Bank and channel work was implemented in these high priority reaches. Channel modification generally entailed narrowing and developing single thread channels in braided sections, adjusting point bar geometry and flood plain elevation, adjusting radiuses in tight or very irregular corners, reducing slopes in cases of excessive grade or head cuts, and establishing pool/riffle sequences. Bank modifications always began with sloping vertical banks to an approximate angle of repose followed by transplanting sod mats and/or mature shrubs. Once banks were sloped and revegetated, techniques including rootwad and tree revetments, rock vane flow deflectors, straw bale bank toe construction, and installation of erosion cloth, were used to protect the new banks.
Click here for more information on methods used.
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Site 18 Installation of the upper rock vane – looking upstream (11/96). Rock va... |
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Reach 11, site 10 Example of completed bank stabilization sloping and juniper re... |
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Monitoring Data and Collection
Methods: The general goals of Deep Creek project monitoring are to determine how well the project restoration activities worked to stabilize the Deep Creek channel and how effective these activities are in moving Deep Creek toward full support of beneficial uses. Targets have been established for each monitoring parameter. Ultimately the monitoring results should determine to what degree general and specific restoration efforts were successful, and if not, why, and how restoration might be better directed in the future. It is important that project monitoring provides meaningful results that are presented in a manner which is constructive to the general public and others involved or interested in this or similar efforts.
Select stabilization practices and best management practices (i.e., bank sloping and revegetation, tree/rootwad revetments, fencing, etc. ) were evaluated to determine how well the practices stabilized stream banks, maintained proper channel geometry, and reestablished riparian vegetation. Monitoring parameters for these factors include: channel cross-sections, photo points, pebble counts, and surface area of eroding banks.
Monitoring of water quality/quantity and fish/macroinvertebrate populations/habitat were conducted to determine if restoration and improved management practices resulted in: 1) decreased suspended sediment, 2) adequate summer stream flow, 3) reduced summer water temperatures, 4) improved migratory fish numbers and 5) macroinvertebrate populations and habitat conditions characteristic of the Deep Creek ecoregion reference conditions.
All monitoring activities contained in this plan were selected to fit within reasonable budget (<10% of total budget) and manpower constraints of the project. Where practical/possible, this plan incorporated monitoring techniques designed to encourage landowner participation in the monitoring process or at least provide results that were meaningful to landowners.
Click here for more information including monitoring charts.
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| Was this project effective
and how was this determined? In general, watershed restoration activities had mixed success. The amount of eroding banks was reduced although temperature and minimum flows remained problematic due to continued drought and warm temperatures. In addition, large wildfires during the summer of 2000 and extensive beaver activity confounded monitoring results.
Click here for more information.
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(Before) Reach 10, site 17 before restoration – steep banks (7/10/97)... |
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(After) Reach 10, site 17 2 years after restoration – revegetated and fenced (8/... |
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Confounding Effects/Additional
Information: There were several confounding factors that had an impact on the success of restoration activities in this project. During 2000, large wildfires burned many acres of timber in the upper watershed. These wildfires, in addition to continued drought, contributed to unusual flow and sediment conditions on Deep Creek during 2001. Flow rates were very low, yet TSS concentrations were high relative to the flow. At some sites, the relationship between TSS and discharge tended toward the opposite of what would “normally” be expected. Some of the lowest TSS values occurred during the highest flows. In addition, two identical TSS values occurred at very different flow rates and two identical flow values resulted in significantly different TSS values (Figure 2). Despite a general decrease in TSS from pre-project levels, similar reductions in flow rates made it impossible to infer whether TSS reductions were related to reduced flows or upstream channel improvements.
Evidence of the impact of wildfires on water quality within the watershed occurred during July 2001. An extreme sediment spate was documented in a TSS sample collected on July 6, 2001. This event, prompted by rainfall in the burned areas of the upper watershed, resulted in a TSS concentration of 6594 mg/L. This was the highest value recorded on Deep Creek since monitoring began in 1991. It represented an approximate 1500-fold increase in TSS concentration over the previous sample collected at this site on June 26, 2001. These unusual circumstances made it problematic to draw conclusions about habitat improvement based solely on restoration activities.
Another confounding factor influencing the success of restoration activities was the presence of beaver dams in the study area. Moisture wicking into the upper banks behind beaver ponds helped establish the herbaceous vegetation located higher on the banks, but continuous inundation of the lower banks drowned out many of the shrubs. The presence of beaver dams also necessitated changes in some cross section monitoring sites. During 2001, beaver dams caused backwater at five cross sections in reaches 10 and 11; cross section D1 in reach 11 could not be measured in 2001 due to excessive water depth caused by beaver ponds. |
| Project
Specs (all specs are estimates): |
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Overall Estimated Cost:
$550,000.00 (including $6330/year for monitoring) For more detailed cost information, refer to Hydrotech's final reports (part I) (part II).
Landowner Contribution:
Cash: In-kind: $142,997.00 (Landowner cash, materials & equip. provided + MCC asst.) |
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| For more information on this project
contact: |
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Ron Spoon, Montana Fish, Wildlife and Parks, Email: fwprs@in-tch.com
Steve Tralles, Hydrotech, Inc., Email: hydrotec@montana.com
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| This information
was collected by: Michelle White and Molly Boucher |
| Project last updated on: 4/30/2007 |
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