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STORY MILL ECOLOGICAL RESTORATION SELECTED
ALTERNATIVE CONCEPTUAL DESIGN REPORT
BOZEMAN, MONTANA
Topical Report RSI-2383
by
Richard McEldowney, PWS
Michael Rotar, PE
RESPEC
3810 Valley Commons Drive, Suite 4
Bozeman, Montana 59718
prepared for
The Trust for Public Land
111 South Grand Ave
Bozeman, Montana 59715
November 2013
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EXECUTIVE SUMMARY
This report documents the approach used in developing a conceptual restoration design for the
Story Mill project area located in northeast Bozeman, Montana. The Story Mill project area is
comprised of three parcels: North Parcel, South Parcel, and the Triangle Parcel. Development
of the conceptual restoration design for the Story Mill project area has followed a stakeholder
driven process. This process began in late 2012 with The Trust for Public Land (TPL) inviting
interested people to provide their opinions on the potential uses of the Story Mill site through
an online survey. This was followed up by holding a community meeting at the Emerson
Cultural Center on February 7, 2013. Following this community outreach by TPL, a group of
stakeholders were assembled by TPL on April 15, 2013 to develop preliminary goals for the
project.
RESPEC was hired at the end of June 2013 and continued this process of stakeholder outreach
combined with the incorporation of technical information to develop a selected conceptual
restoration design. While several components have occurred simultaneously, this process has
generally followed a sequence of steps intended to deliver a restoration design that accomplishes
stated goals/objectives, provides the services and amenities sought after by stakeholders and the
Bozeman community, and that is cost effective and constructible within the constraints of the
site. The series of steps used in this process and described in this report are:
Development of an ecological conceptual model→ Refine goals/Performance
Metrics→ Collect, compile, and collate data→ Determine design elements for use
in conceptual restoration alternatives→ Develop an evaluation matrix→
Complete conceptual restoration design→ Package design into three restoration
alternatives→ Select one conceptual restoration alternative.
The overarching ecological goal for the project is:
In consideration of site constraints and other project goals, restore and protect on-site
natural processes necessary for a functioning riparian and wetland system.
This goal is supported by the following five ecological objectives:
E-1 Provide hydrologic connectivity between stream floodplain and wetlands to maximize
riverine and wetlands habitat diversity.
E-2 Remove river process constraints and non-natural features to the extent possible in the
context of land ownership and access.
E-3
Remove or modify drainage and excavated features that disrupt and diminish
groundwater-dependent wetland extent and functioning to restore wetland functions to the
extent site constraints allow.
E-4 Demonstrate improved water quality (temperature, nutrients and sediment measures).
E-5 Restore native plant diversity (upland, wetland and riparian communities) and minimize
invasive plants.
The design process for restoration of wetland, riparian, and stream systems at the Story Mill
site included the conceptual level design of three alternatives and, subsequently, comparison
and selection of a preferred alternative. Three alternatives were developed that emphasized
varying levels of ecological restoration actions and benefits. All alternatives were developed
with the intention of meeting the ecological project goal and five objectives, as well as
integrating with the public access and recreational use planning that is being conducted as a
parallel design process. Brief descriptions of each alternative are provided below.
Alternative 1 - Ecological Restoration I
Alternative 1 would maximize restoration potential of wetland, riparian, and stream
ecological processes within the physical and administrative constraints imposed on the site,
while providing for public access and recreation and including key project elements for the
enhancement of water quality in the East Gallatin River. Ecological function under Alternative
1 is maximized through the removal of all structures and most existing infrastructure on the
property, restoring historic drainage conditions to enhance and expand existing wetlands, by
providing connectivity between the channel and floodplain, removing floodplain and wetland
fill, and removing riprap and trash from the channel, banks, floodplain and wetlands, and by
implementing an aggressive planting program that re-naturalizes the area with native plants
and removes non-native plants.
Alternative 2 - Ecological Restoration II,
Alternative 2 would achieve significant restoration of wetland, riparian and stream ecological
processes while retaining select structures and emphasizing less intensive treatment options.
Functionality would be improved through the removal of most existing structures on the
property, restoring historic drainage conditions, providing improved connectivity between the
channel and floodplain, removing floodplain and wetland fill, and removing riprap and trash
from the channel, banks, floodplain and wetlands, and by implementing an aggressive planting
program that re-naturalizes the area with native plants and removes non-native plants.
Alternative 3 – Passive Restoration
The Passive Restoration Alternative allows for passive restoration of the project site in which
no active restoration activities are pursued other than removal of select structures, selective
removal of trash from the channel and banks, and the long term management of invasive weeds.
Under the Passive Restoration Alternative ecological processes may continue to function at
reduced levels but may ultimately return to a greater level of function over a much longer
timeframe (decades).
The Selected Alternative is a combination of Alternatives 1 and 2, which will maximize
benefits to water quality, wetlands, and streams. As proposed, the Selected Alternative will
more than double the amount of wetlands found on the site, adding roughly 8.0 acres of restored
wetlands to the roughly 7.5 acres of wetlands currently occurring on the three parcels that
make up the project area. Vegetative diversity is improved through native plantings,
restoration of site hydrology, and ongoing weed control efforts. It would also restore natural
fluvial processes along 2,580 feet of the East Gallatin River through the removal of sidewalk
rubble used as makeshift riprap, and the removal of old machinery and trash embedded in the
channel and streambanks.
The Selected Alternative maintains the extent of the current pond on the South Parcel, but
naturalizes the shoreline through grading and willow plantings. The potential for surface water
quality improvements to Bozeman Creek is maximized through the creation of a new 1 acre
backwater slough that will promote the deposition and uptake of nutrients found in creek
waters. Surface water quality improvements are also proposed for the East Gallatin River on
the Triangle Parcel and on the North Parcel. On these parcels the East Gallatin River is fairly
incised and does not have as much access to its floodplain as is desirable. The solution proposed
by the Selected Alternative is to create roughly 2.9 acres of new floodplain area, of which
roughly 70% would be wetlands and 30% riparian forest. In addition, three new public access
points to the East Gallatin River are proposed under the Selected Alternative.
Construction of the Selected Alternative would require the excavation of over 20,000 cubic
yards of fill material. This material is planned to be repurposed and used as fill in a currently
topographically depressed area of the North Parcel. This will minimize haul costs and assist in
the construction of other park amenities, such as a parking lot. The projected construction cost
for restoration actions under the Selected Alternative is $584,200. As part of the proposed
restoration actions, this includes the demolition and removal of the farm buildings found on the
South Parcel and the storage garage on the Triangle Parcel, but does not include removal of the
old slaughterhouse buildings or bridge found on the Triangle Parcel. Technical assumptions
used in developing the cost estimate are provided.
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i
TABLE OF CONTENTS
1. 0 INTRODUCTION ............................................................................................................. 1
1.1 GENERAL APPROACH ............................................................................................. 1
2. 0 ECOLOGICAL CONCEPTUAL MODEL FOR RESTORATION .............................. 4
3. 0 REVISE GOALS AND DEVELOP PERFORMANCE CRITERIA ............................ 9
3.1 VISION ....................................................................................................................... 11
3.2 OVERARCHING ECOLOGICAL GOAL ................................................................... 11
4. 0 DATA GATHERING ........................................................................................................ 14
5. 0 ALTERNATIVE DEVELOPMENT ................................................................................ 17
5.1 ALTERNATIVE 1—ECOLOGICAL RESTORATION I ............................................ 17
5.2 ALTERNATIVE 2—ECOLOGICAL RESTORATION II .......................................... 19
5.3 ALTERNATIVE 3—PASSIVE RESTORATION ....................................................... 19
6. 0 EVALUATION MATRIX ................................................................................................. 20
7. 0 RESTORATION DESIGN ............................................................................................... 25
7.1 DESIGN PROCESS .................................................................................................... 25
7.1.1 Precipitation Analysis ...................................................................................... 25
7.1.2 Surface Water Analysis ................................................................................... 26
7.1.3 Alluvial Groundwater Analysis ....................................................................... 29
7.1.4 Water Rights Analysis ..................................................................................... 32
7.1.5 Vegetation Analysis ......................................................................................... 32
7.1.6 Projected Wetland Establishment ................................................................... 33
7.1.7 Cost Estimating ............................................................................................... 34
7.2 ASSUMPTIONS ......................................................................................................... 34
7.3 DESIGN CONSTRAINTS .......................................................................................... 35
8. 0 RESTORATION ALTERNATIVES ............................................................................... 37
9. 0 SELECTED ALTERNATIVE .......................................................................................... 41
10. 0 REFERENCES ............................................................................................................... 45
ii
APPENDICES
APPENDIX A HYDROLOGIC AND HYDRAULIC ANALYSES FOR STORY MILL
RESTORATION PROJECT .................................................................................................... A-1
APPENDIX B PLANT SPECIES IN THE STORY MILL PROJECT AREA .................. B-1
APPENDIX C ASSUMPTIONS USED IN THE DEVELOPMENT OF THE
CONCEPTUAL ALTERNATIVES ......................................................................................... C-1
APPENDIX D CONCEPTUAL RESTORATION DESIGN ALTERNATIVE
FIGURES ................................................................................................................................... D-1
APPENDIX E CONCEPTUAL RESTORATION DESIGN SELECTED
ALTERNATIVE FIGURES ..................................................................................................... E-1
iii
LIST OF TABLES
TABLE PAGE
Table 2-1. Site Characteristics Relevant to Restoration Actions ......................................... 5
Table 3-1. Participants in the Ecological Goals and Performance Criteria Development
Meeting, July 19, 2013 .................................................................................................. 9
Table 3-2. Ecological Objectives and Performance Metrics for the Story Mill Project Site
(Page 1 of 2) ................................................................................................................... 12
Table 4-1. Summary List of Data Collected and Its Relevance to Restoration Design of
the Story Mill Project Site (Page 1 of 3) ....................................................................... 14
Table 5-1. Restoration Design Elements by Alternative For the Story Mill Project ........... 18
Table 6-1. Explanation of Evaluation Criteria (Page 1 of 2) ................................................ 21
Table 6-2. Explanation of Evaluation Criteria (Page 2 of 2) ................................................ 22
Table 6-3. Evaluation Criteria and Their Relevance to the Ecological Objectives of the
Story Mill Project (Page 1 of 2) ..................................................................................... 23
Table 7-1. Precipitation Values (Inches) For the Story Mill Project Area [Western
Regional Climate Center, 2013] ................................................................................... 26
Table 7-2. Predicted Flow Events For the East Gallatin River ........................................... 28
Table 8-1. Evaluation Matrix for Three Conceptual Restoration Design Alternatives
Proposed For the Story Mill Project Area .................................................................... 38
Table 8-2. Summary Costs of Restoration Design Elements at the Story Mill Project
Area (Estimated by M. Johnson and Reviewed by M. Rotar and R. McEldowney
September 10, 2013) (Page 1 of 2) ................................................................................ 39
Table 9-1. Relative degree Selected Alternative restoration actions proposed for each
parcel accomplish restoration objectives.. ................................................................... 44
iv
LIST OF FIGURES
FIGURE PAGE
1-1 Story Mill Project Location Map ................................................................................... 3
2-1 Ecological Conceptual Model for Wetland and Stream Restoration at the Story
Mill Project Site ............................................................................................................. 6
3-1 Projected Ecological Potential for the Story Mill Project Site ..................................... 11
7-1 Precipitation Graph for the Story Mill Project Area .................................................... 26
7-2 Cumulative Water Flow for the East Gallatin River—Water Year 2012 ................... 28
7-3 Cumulative Water Flow for the East Gallatin River—Water Year 2013 ................... 28
7-4 Groundwater Well Locations on the South Parcel of the Story Mill Project Area ..... 30
7-5 Depth to Groundwater and Discharge of the East Gallatin River .............................. 31
1
1.0 INTRODUCTION
This report documents the approach used in developing a conceptual restoration design for
the Story Mill project site located in northeast Bozeman, Montana, as shown in Figure 1-1. The
Story Mill project site is located at approximately 45°41ꞌ55ꞌꞌ N, 111°1ꞌ21ꞌꞌW in Gallatin County
(Figure 1-1). It encompasses portions of SE ¼ of Section 31 and SW ¼ of Section 32 in
Township 1S, Range 6E, as well as portions of NE ¼ of Section 6 and NW ¼ of Section 5 in
Township 2S, Range 6E.
1.1 GENERAL APPROACH
The development of the conceptual restoration design for the Story Mill project area has
followed a stakeholder driven process. This process began in late 2012 when The Trust for
Public Land (TPL) invited interested people to provide their opinions on the potential uses of
the Story Mill site through an online survey. Six hundred and ninety surveys were completed
primarily by people living within Gallatin County, and 72 percent of which live in Bozeman.
This survey was followed-up by holding a community meeting at the Emerson Cultural Center
on February 7, 2013. Over 140 community members attended the meeting. Respondents to the
survey and attendees of the meeting indicated that their top usage options included the
following:
To enhance trail connections along the Story Mill spur trail
To restore wetlands to benefit water quality
To create a new, natural area park for the city
To create a nature sanctuary.
The top activities sought after in a new park were the use of new trails, opportunities to
enjoy the river and water features, and opportunities for wildlife viewing.
After this community outreach, TPL assembled a group of stakeholders on April 15, 2013, to
develop preliminary goals for the project. RESPEC was hired at the end of June 2013 and
continued this process of stakeholder outreach combined with the incorporation of technical
information to develop a selected conceptual restoration design. While several components have
occurred simultaneously, this process has generally followed a sequence of steps intended to
deliver a restoration design that accomplishes stated goals/objectives, provides the services and
amenities sought after by stakeholders and the Bozeman community, and is cost effective and
constructible within the constraints of the site. The series of steps used in this process and
described in this report include the following:
2
Development of an ecological conceptual model→ Refine goals/Performance Metrics→
Collect, compile, and collate data→ Determine design elements for use in conceptual restoration
alternatives→ Develop an evaluation matrix→ Complete conceptual restoration design→
Package design into three restoration alternatives→ Select one conceptual restoration
alternative.
3 Figure 1-1. Story y Mill Project LLocation Map. RSI-2274-13-001
4
2.0 ECOLOGICAL CONCEPTUAL MODEL FOR RESTORATION
A conceptual model of the riparian/wetland ecosystem occurring within the Story Mill project
area was developed. The goals of the conceptual model include the following:
Synthesize information about key riparian ecosystem components and drivers found at
the Story Mill project site
Clearly illustrate the dominant relationships among ecosystem elements and historic,
ongoing, and potential future stressors found at the site
Facilitate communication about the key system components and processes found at the
site and their relationships to ecological restoration
Support management decisions about the site
Identify data gaps for adaptive management
Assist in identifying the specific prescription needed to restore site health and function.
The ecological processes within the project site occur at the regional, watershed, and local
scales. The regional scale is the defined as the Townsend Basin Level IV Ecoregion. The
watershed scale is defined as the combined extent of the 12-digit hydrologic unit codes (HUCs)
for Bozeman Creek and the four 12-digit HUCs that make up the East Gallatin River’s
watershed, and the downstream end of each HUC originates at their confluence. The total
drainage area is 151.3 mi2. The local scale, where any planned restoration activities would be
implemented, are within the Story Mill properties owned by TPL and depicted in Figure 1-1.
The temporal scale used in the conceptual model extends from pre-European settlement to
current day for existing conditions and current functionality of the site. To capture the
potential effects of ecological restoration of the site, the temporal scale extends from today into
the future for 25 years. Furthermore, several of the functions provided by Story Mill riparian
areas are either limited to the growing season, or operate most effectively during the growing
season. The growing season on the Story Mill site generally extends from April 20 through
October 12 [Natural Resources Conservation Service, 2002].
While not comprehensive, the characteristics most relevant to any restoration actions taken
on the site are captured in Table 2-1, and the most relevant relationships are shown in
Figure 2-1.
5
Table 2-1. Site Characteristics Relevant to Restoration Actions
Site Characteristics
CLIMATE (1981–2012)
Growing Season (28°F or greater, 50 percent of the time)
May 5–October 1; 149 days
Temperature (°F)
Minimum = –32 (December 1983); Maximum = 100 (July 2002 and July 2007)
Precipitation (inches)
Minimum = 12.42 (2001); Maximum = 25.57 (1997)
Mean = 19.46; Median = 19.03
Mean annual snowfall = 91.86 (primarily November–April)
WATERSHED CHARACTERISTICS
Igneous geology in upper Bozeman Creek’s Watershed and alluvial at lower elevations
Sedimentary geology in upper East Gallatin River’s Watershed and alluvial at lower elevations
Site occurs at an elevation of 4,725 feet above mean sea level
Urbanization
Agriculture
Nonpoint-source pollution has degraded water quality in both creeks—nitrogen, phosphorous, fecal
coliforms, and sediment.
SURFACE FLOW REGIME/ALLUVIAL AQUIFER
Snowmelt hydrograph
Alluvial groundwater depths ranged from 0 to 57 inches below ground surface (bgs) in May 2013, generally tracked with the flow in the creeks, and dropped as the summer progressed.
The alluvial groundwater flows from south to north.
FLOODPLAIN SOILS
Site generally contains silty clay and clay loams in upper profile, sand, and gravels at deeper depths.
Alluvial GW is mainly associated with the sand/gravel layer
The western portion of the site, closer to Bozeman Creek, is generally more clayey than other areas of
the site.
SITE GEOMORPHOLOGY
Floodplain/valley bottom—depositional
Confluence of Bozeman Creek and the East Gallatin River
Site has been graded and drained for agriculture and a residence
Bozeman Creek and the East Gallatin River are both pool/riffle (C4) streams
Site generally drains from south to north.
RIPARIAN VEGETATION
Highly disturbed—majority of the site is grassland and dominated by introduced and invasive/noxious
species
Palustrine emergent (PEM) wetlands in meadows and Palustrine scrub-shrub (PSS) wetlands along
creeks. Patches of coyote willow occur on the southwest side of the site
An aspen grove occurs on the northeast side of the site.
ANIMALS
Migratory birds (e.g., Sandhill Cranes, waterfowl, and songbirds)
Whitetail deer
Beaver.
FigRSI-2274-13-002 ure 2-1. Ecologgical Conceptuaal Model for Wet tland and Stream Restoration aat the Story Milll Project Area. 6
7
Site Observations Relevant to the Conceptual Model
1. Precipitation, or lack thereof, drives runoff in the system. Snowpack has historically
been the primary source of runoff.
2. The characteristics of the watershed influence the timing, frequency, magnitude, and
duration of runoff. Urbanization and agriculture are two of the main watershed
characteristics that affect runoff and sedimentation in the project area by increasing the
area of impervious surfaces. Impervious surfaces increase surface runoff, decrease time
to runoff, and decrease infiltration and percolation into the shallow groundwater system
and, thereby, potentially reduce the overall availability of groundwater, and/or the
timing or duration that shallow groundwater is available on the site for wetland/riparian
development. Agricultural modifications to channels, including channelization and bank
protection, can increase stream power, reduce floodplain access, and promote bank/bed
erosion. Surface water diversions, particularly for agricultural uses, can reduce late
summer streamflows, which has consequences on water availability for plants and can
increase water temperatures in the creeks.
3. Estimated 2-, 5-, 10-, and 25-year peak flows for Bozeman Creek in the project area are
235, 421, 577, and 807 cubic feet per second (cfs), respectively (RESPEC 2013).
4. Estimated 2, 5, 10, and 25 year peak flows for the East Gallatin River upstream of its
confluence with Bozeman Creek are 387, 633, 828, and 1,120 cubic feet per second (cfs),
respectively [RESPEC, 2013].
5. The flooding of Bozeman Creek and the East Gallatin River is typically asynchronous.
6. On site water availability and timing affects the types of riparian and wetland
vegetation that will grow there. The increased disturbance levels of active floodplains
caused by flashier runoff enables the establishment and persistence of invasive species
in urban riparian corridors.
7. Erosion and depositional processes of Bozeman Creek and the East Gallatin River from
natural and anthropogenic influences have shaped what remains of the site’s original
macro and microtopography, including the overall drainage of the site, the original
drainage swales, and the higher terrace in the northeast corner of the site.
8. Topography influences seed deposition, establishment, and persistence. Site
geomorphology directly affects the site’s overall water regime, as well as the microsite
water regime, which has direct consequences on plant composition and density. For
example, cattails have a competitive advantage in areas that remain inundated for
longer periods of time. A site with a diverse water regime generally leads to a higher
diversity of niches available for plants and animals to inhabit, which has consequences
on productivity, nutrient cycling, foodchain and trophic relationships, as well as the
rates of biogeochemical processes occurring in the soil.
8
9. Ice production for food storage is presumably the reason the pond was originally
excavated on the site.
10. Site clearing and hay production has had profound consequences to the vegetation found
on the site, including the clearing of native riparian vegetation, the introduction and
establishment of pasture grasses (including brome, orchard grass, timothy, reed canary
grass, and Garrison creeping foxtail), and the introduction of noxious weeds (tansy, leafy
spurge, and Canada thistle).
11. Agriculture and urbanization in the watershed continue to provide nutrient-laden runoff
to the site via surface and groundwater flows.
12. The textures of on-site floodplain soils determines the baseline available water holding
capacity and fertility of the site and, thereby, strongly influences which plant species
will have a competitive advantage on the site.
13. Beaver have inhabited the site in the past and may be an important consideration in
reestablishing woody plants on the site, particularly aspen and willows. Beaver
management may become an important issue as the site is restored and becomes more
naturalized.
9
3.0 REVISE GOALS AND DEVELOP PERFORMANCE CRITERIA
Several goals for ecological restoration of the site were developed by a stakeholder group in
April 2013. While these original goals went toward identifying and formulating the desired
outcomes for ecological restoration of the site, the RESPEC team felt that they needed
additional refinement, that visualizing and identifying the desired future condition of the site
and developing specific performance criteria would benefit the project and serve to establish the
restoration philosophy used by the design team.
To this end, a meeting of the project stakeholders listed in Table 3-1 was held at TPL offices
in Bozeman, Montana, on July 19, 2013. The purpose of the meeting was to discuss the
ecological goals and performance criteria for restoration actions at the Story Mill project area.
The meeting was facilitated by Mr. Rich McEldowney and Mr. Mike Rotar of RESPEC.
Table 3-1. Participants in the Ecological Goals and Performance Criteria
Development Meeting, July 19, 2013
Name Organization Title Telephone Email
Rich
McEldowney RESPEC Riparian
Ecologist 406.599.2138 rich.mceldowney@respec.com
Tom Hinz TPL Consultant 406.580.1950 ecolegacyconsulting@gmail.com
Pat Byorth
Trout Unlimited/
Greater Gallatin
Watershed
Council
Vice Chair 406.548.4830 pbyorth@tu.org
Peter Skidmore Consultant Principal 406.600.8536 peter@peterskidmore.com
Maddy Pope TPL Project
Manager 406.522.7450 maddy.pope@tpl.org
Michael Rotar RESPEC
Water
Resources
Engineer
406.570.1035 mike.rotar@respec.com
Steve Carpenedo
Montana
Department of
Environmental
Quality
Wetland
Scientist 406.444.3527 scarpenedo2@mt.gov
Because the project area has been so disturbed over the years, photographs from several
wetlands in the area were shared with the group to promote a discussion about the ecological
potential of the site. These photographs included the following:
Bridger Creek upstream of Drinking Horse Mountain
Bridger Creek near the Bridger Creek Golf Course
10
Bozeman Creek north of Goldenstein Road
Groundwater dependent wetlands near Morningstar Elementary School
East Gallatin Recreation Area (located just downstream from the project area).
These wetlands were then contrasted by specific slides of the East Gallatin River, Bozeman
Creek, and the groundwater-supported wetlands found on the Story Mill project area that have
been impacted by over 100 years of human habitation and agricultural modifications.
The following points were made by the stakeholders:
1. The preferred future condition of the site is for it to reach its ecological potential, as
shown in Figure 3-1. Based on less-disturbed wetlands found in the area, the ecological
potential of the site is a riparian forest and shrub complex with scrub/shrub and
emergent wetlands in the lower/wetter areas. The dominant hydrology will be the
creeks along the two stream corridors and alluvial groundwater in the central portion of
the site.
2. The confluence of Bozeman Creek and the East Gallatin River makes the presence of
wetlands both critical and priceless for the services they provide humans and wildlife.
For this reason, wetland acreage on the site should be maximized within the constraints
found on the site.
3. To the extent possible, restoration activities should be process based, and they should
focus on removing human-imposed stressors on the system, so the site can heal itself.
This will be particularly effective along the stream corridors. This type of approach will
protract the restoration timeframe, but it is significantly less expensive and, ultimately,
more sustainable and preferable.
4. The groundwater-dependent wetlands in the central portion of the site have been
dramatically altered and will require a much more active approach to restoration.
5. Design alternatives should include additional restoration activities to be completed in
the future.
6. The public should be informed about the healing process. While not expanded on during
this meeting, thoughts included: (1) why restoration is important, (2) specific process-
based remedies and habitat-specific actions being implemented for site restoration,
(3) the timeframe for restoration, and (4) the constraints affecting site restoration.
7. Access to the creeks is a high priority for the public.
The results of the group effort and the ongoing development of the goals and performance
criteria by Mr. McEldowney and Mr. Rotar are provided in Table 3-2. Note that several of the
performance metrics will continue to be developed as the site continues to be studied and
understood during the ongoing restoration design process.
RSI-2274-1
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11
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12
Table 3-2. Ecological Objectives and Performance Metrics for the Story Mill Project
Site (Page 1 of 2)
Ecological
Objectives
Performance
Metrics
Time
Frame
E-1
Provide hydrologic connectivity
between stream floodplain and wetlands to maximize riverine and
wetlands habitat diversity.
1. Flows > than the effective discharge
have ready access to the floodplain in
Bozeman Creek (BC) and East Gallatin
River (EGR).
2. The post-restoration extent of the
active floodplain is significantly
greater (at least 50 percent) than the
pre-restoration, active floodplain. The
active floodplain is defined as the area
subject to flooding during the 2-year
flood event.
At completion
At completion
E-2
Remove river process constraints
and non-natural features to the
extent possible in the context of
land ownership and access.
1. 100 percent of streambanks and
streambed on TPL property and
adjacent property with granted
restoration access are free of human-
imposed constraints.
At completion
E-3
Remove or modify drainage and
excavated features that disrupt
and diminish groundwater-
dependent wetland extent and functioning to restore wetland
functions to the extent site
constraints allow.
1. Natural drainage patterns are restored
to the site.
2. Wetland hydrology is documented in
12 of the 15 groundwater wells
(80 percent). Wetland hydrology is
defined as depth to water within
12 inches of the soil surface for
14 consecutive days during the growing
season (May 5 to Oct. 1).
3. Post-restoration extent of groundwater-dependent wetlands is
significantly greater (at least
50 percent) than pre-restoration
groundwater wetland extent.
4. Using the 2008 Montana Wetland
Assessment Method, functional units
found on the site are increased by
50 percent.
At completion
5 years
E-4
Demonstrate improved water
quality (temperature, nutrients,
and sediment measures).
1. Reduction and moderation of diurnal
and seasonal surface and groundwater
temperature fluctuations within the
project area during late summer
(August 15–September 30) (Modify as
needed as monitoring information
becomes available).
2. Grid toss in pool tailouts shows a 25 percent reduction in fine sediment
within, and directly below, the project
area.
3. Develop metric for nutrients either using monitoring data (if possible), or
based on TMDL.
5–10 years
13
Table 3-2. Ecological Objectives and Performance Metrics for the Story Mill Project
Site (Page 2 of 2)
Ecological
Objectives
Performance
Metrics
Time
Frame
E-5
Restore native plant diversity
(upland, wetland and riparian
communities) and minimize
invasive plants.
1. Native plant canopy cover is
≥ 80 percent in each community type.
2. Ecological integrity is improving based
on a Floristic Quality Assessment
(FQA). The trend of the mean
coefficient of conservatism (using all species) and the Floristic Quality Index
(FQI) are increasing in all community
types or are within 0.1 unit of a
reference condition.
3. Tree and shrub species exhibit diverse
ages, as exhibited by differing heights
and the active recruitment and
establishment of young trees and
shrubs.
4. A long-term monitoring consortium is
established to document change in
vegetation communities and provide
feedback for management decisions.
10 years
14
4.0 DATA GATHERING
A list of the data collected for use in the restoration design is provided in Table 4-1.
Table 4-1. Summary List of Data Collected and Its Relevance to Restoration Design
of the Story Mill Project Site (Page 1 of 3)
Data Collected Relevance to Design
2013 Topographic
Data
(LiDAR data)
• Used in park planning and layout
• Used in park management—access points, passive versus active recreation areas,
and safety planning
• Used to identify where earth moving modifications are needed to create different
features
• Used to quantify earth moving requirements, which are then used in developing
construction cost estimates
• Used in conjunction with site-specific channel survey and cross-section data for
hydraulic modeling
Building Structural
Report
• Provides information needed for cost estimates for demolition or for ongoing
maintenance costs
Climate
• Helps to establish restoration potential
• Used in water budgeting
• Used in construction planning
Existing
Infrastructure and
Utility Locations
• Typically used as a design constraint for features to avoid disturbing or to remove.
• Can be used to identify infrastructure that will be removed or re-purposed
• Used in park planning
Floodplain mapping
• Provides an understanding of estimated water surface elevations under flood
conditions and the extent to which the site could be impacted during a 1%-annual-
chance flood event
Flow modeling/
simulations
(HEC-RAS)
• An important tool for visualizing and evaluating design alternatives
• Simulate spatial extent and depth of water within the channel areas and across
the floodplain to understand how different elements in the proposed alternatives
affect water flow and distribution within the project area
• Modeling can help to identify potential problem areas for management and/or design consideration
Historic and Existing
Wetland Mapping
• Provides context for the project
• Helps to show how the site has changed over time–site trajectory, geomorphic
analysis, and vegetation analysis
• Helps to establish restoration potential
• Can provide insight for design elements
Historic-to-Recent
Aerial Photographs
• Place site in context with its surroundings
• Establish level of departure from undisturbed or less-disturbed conditions
• Helps to establish a restoration potential for the site
• Can help to identify past disturbances that may not be immediately obvious today
15
Table 4-1. Summary List of Data Collected and Its Relevance to Restoration Design
of the Story Mill Project Site (Page 2 of 3)
Data Collected Relevance to Design
On-Site Groundwater
Elevations
• Alluvial groundwater is an important driver in wetland establishment; in general,
knowledge of the physical and chemical characteristics of the soils found on site is
important to understanding the site’s restoration potential
• Used in water budgeting (infiltration and saturated hydraulic conductivities)
• Useful to help identify which vegetation communities can be established where
• In conjunction with surface water information, groundwater information improves
understanding of how the site functions at different times of the year, and how
that affects the spatial extent of wetlands and riparian areas found on site
• Used in design as a site constraint to limit extent of flooding, to understand the
functional limits of what is possible
• Construction planning
Period of Record
Stream Flow Data
• Identify timing and characteristic discharge in each creek, such as bankfull
discharge, peak and, low-flow discharges
• Informs restoration goals and success criteria and can be used as a quantitative
metric in specific success criteria
• Important for specific design elements related to bank repair and reactivation of
secondary channels on the East Gallatin River
• Evaluation of the potential to include stormwater-quality elements into the design
for Bozeman Creek
• Assists with identification of the type of bioengineering methods to be used where
• Depending on design, they are often useful for identifying revegetation zones
• Important to understanding alluvial groundwater levels observed on the site
• Can help with on site management decisions (e.g., risk assessments and
placement and type of infrastructure)
• Construction-related issues, such as access
• Needed for permitting
Phase 1
Environmental Site
Assessment
• Identifies if there are any hazardous materials known to occur on the site that
may need special remediation or consideration
Photographic Inventory • Provides a visual record of baseline conditions for a comparison to post-construction conditions
Soils
• The physical and chemical characteristics of the soils found on site are important
to understanding the site’s restoration potential
• Used in water budgeting (infiltration and saturated hydraulic conductivities)
• Useful to help identify which vegetation communities can be established where
• Used to identify if soil amendments (e.g., compost) are needed or not to promote
vegetation establishment and growth
Stream Channel and
Pond Survey Data
• Longitudinal profiles assist in understanding how the current system operates
and what is needed to meet desired future condition (e.g., pool-glide-riffle-run
relationships)
• Channel cross-sections provide a better understanding of how the site performs
relative to its discharge
• Data is used in design to show what needs to be completed where, such as bank
treatments
• Bathymetry data from pond will be used to determine earth moving requirements,
and revegetation components
16
Table 4-1. Summary List of Data Collected and Its Relevance to Restoration Design
of the Story Mill Project Site (Page 3 of 3)
Data Collected Relevance to Design
Stream Channel
Pebble Counts
• Provides information on stream power and shear stress needed in design for
channel sediment competency calculations (e.g., aggradation/degradation
predictions)
• Provides information on sediment supply entering the stream upstream of the
project area and allows the design to accommodate those inputs
• Data can be used to help identify sediment supply problems and habitat
impairment issues
Vegetation Mapping
• Noxious weed treatments
• Recreation planning—maintenance requirements and activity centers
• Revegetation planning, such as layout and composition of native species and
communities found on site, prioritization of areas to keep natural, and other areas
to convert
• Wetland layout
• Potential to salvage wetland soils and/or vegetation
• Identify sources of plant material for revegetation (e.g., willow cuttings and sedge
mats)
Water-Quality
Information
• Provides context for the project
• Can inform decision making on restoration goals and success criteria related to water quality
• Can help identify specific design elements needed to improve water quality (e.g.,
retention times)
Water Rights Review
• Consultation with the MT Department of Natural Resources Consrvation (DNRC)
on constraints posed by water availability for the project and different design
elements that would not be acceptable for use in the project
Watershed
Groundwater
Information
• Provides context for the project
• Use regional groundwater reports for the lower Gallatin watershed to better
understand watershed-scale groundwater movement and seasonality
Watershed Report for
the Lower Gallatin • Provides context for the project
Wetland Functional
Assessments
• Identifies baseline conditions of different wetland functions operating on the site
• Useful as a success criteria—functional lift
• Helps identify specific design elements or types of design elements that could be
incorporated into the design to enhance or restore specific functionality
• Helps to identify stressors/constraints affecting the site that can temper
restoration expectations
17
5.0 ALTERNATIVE DEVELOPMENT
The design process for restoring wetland, riparian, and stream systems at the Story Mill site
included the conceptual level design of three alternatives and, subsequently, comparing and
selecting a preferred alternative. Developing the three alternatives was conducted with the
understanding that ultimately the selected alternative may include a combination of restoration
elements from more than one of the alternatives in order to strike a balance between budgetary
constraints and conservation and recreation goals.
Alternative development was accomplished by meeting with TPL on August 5, 2013, to
develop restoration approaches or themes and discuss specific constraints affecting ecological
restoration of the site, and the specific design elements that could be used to address site
constraints and achieve project goals.
Through this meeting and a subsequent follow-up with meeting participants, three
alternatives were developed that emphasized varying levels of ecological restoration actions and
benefits. The descriptions of each alternative are provided below and the list of specific design
elements assigned to each alternative is provided in Table 5-1. All alternatives were developed
with the intention of meeting ecological project goals and integrating with the public access and
recreational use planning that is being conducted as a parallel design process. The extent of
removing existing structures and infrastructure, that currently constrain ecological processes, is
a dominant variable used to differentiate among the three alternatives. A “minimal action”
alternative was included to provide a comparison of anticipated outcomes and associated costs
of the two restoration alternatives to a minimal level of site stewardship.
5.1 ALTERNATIVE 1—ECOLOGICAL RESTORATION I
Alternative 1 would maximize the restoration potential of wetland, riparian, and stream
ecological processes within the physical and administrative constraints imposed on the site,
while providing for public access and recreation and including key project elements for the
enhancement of water quality in the East Gallatin River. Restoring ecological processes would
maximize wetland, riparian, and stream functionality for water-quality improvement, flood flow
attenuation, wildlife and fish habitat, short- and long-term surface water storage, foodchain
support, groundwater discharge/recharge, and the site’s potential for recreation and education.
Ecological function is maximized by removing all structures and most existing infrastructure on
the property; restoring historic drainage conditions to enhance and expand existing wetlands;
providing connectivity between the channel and floodplain; removing floodplain and wetland
fill; removing riprap and trash from the channel, banks, floodplain and wetlands; and
implementing an aggressive planting program that re-naturalizes the area with native plants
and removes non-native plants.
18
Table 5-1. Restoration Design Elements by Alternative For the Story Mill Project
Restoration Design Elements
Alternative
1 2 3 Selected
Alternative
North Parcel
Expand East Gallatin River floodplain, excavate fill,
and expand potential for water-quality improvement +++ ++ — ++++
Pedestrian river access
Restore wetland and vegetative diversity +++ ++ + +++
River corridor cleanup—remove riprap and trash —
South Parcel
Remove farm buildings
Keep driveway up to bend for trail
Reconfigure pond/ditch —
Excavate Bozeman Creek floodplain, and expand
potential for water-quality improvement — —
Restore wetland and vegetative diversity +++ ++ + +++
Pedestrian river access — — — —
Pedestrian wetland observation trails —
Multiuse connector trail
River corridor cleanup—remove riprap and trash on
the south (left) bank — —
Triangle Parcel
Remove garage
Remove slaughterhouse buildings — — —
Remove bridge — — —
Pedestrian river access (convert driveway) —
Truncate driveway at house —
Expand East Gallatin River floodplain, excavate fill,
and expand potential for water-quality improvement ++++ ++ — +++
Restore wetland and vegetative diversity +++ ++ + +++
River corridor cleanup—remove riprap and trash +++ ++ — ++
= included in alternative
— = not included in alternative
++++ = highest level of effort; + = lowest level of effort.
19
5.2 ALTERNATIVE 2—ECOLOGICAL RESTORATION II
Alternative 2 would achieve significant restoration of wetland, riparian, and stream
ecological processes while retaining select structures and emphasizing less intensive treatment
options. Restoring ecological processes would restore significant wetland and riparian
functionality for water-quality improvement, flood flow attenuation, wildlife and fish habitat,
short- and long-term surface water storage, foodchain support, groundwater discharge/recharge,
and the site’s potential for recreation and education. Functionality would be improved by
removing most existing structures on the property; restoring historic drainage conditions;
providing improved connectivity between the channel and floodplain; removing floodplain and
wetland fill; removing riprap and trash from the channel, banks, floodplain and wetlands; and
implementing an aggressive planting program that re-naturalizes the area with native plants
and removes non-native plants.
5.3 ALTERNATIVE 3—PASSIVE RESTORATION
Alternative 3 allows for the passive restoration of the project site in which no active
restoration activities are pursued other than removing select structures, and trash from the
channel and banks as well as the long-term management of invasive weeds. Under the Passive
Restoration Alternative, ecological processes may continue to function at reduced levels but may
ultimately return to a greater level of function over a much longer time frame (decades).
20
6.0 EVALUATION MATRIX
Eighteen criteria were developed to evaluate each of the alternatives in an objective manner.
When possible, they were made quantifiable. These evaluation criteria are discussed in Table
6-1 and Table 6-2 lists how each relates to the five ecological restoration objectives. Six of the
criteria are general project considerations, five are related to financial concerns, six relate to the
first objective (E-1), five relate to each of the second and third objectives (E-2 and E-3), seven
relate to the fourth objective (E-4), and six relate to the fifth objective of the project (E-5).
21
Table 6-1. Explanation of Evaluation Criteria (Page 1 of 2)
Evaluation Criteria Comments
1. Probability of meeting ecological objectives (low,
moderate, high)
Provides a general, overall idea of how each of the
alternatives meet ecological objectives. More specific
quantitative measures are provided in other criteria.
2. Relative complexity of project; difficulty of
implementation (low, moderate, high)
Provides a qualitative measure of risk of project delays and
budget overruns. It is based on the relative complexity
involved in implementing an alternative. The underlying logic is that the more complex the alternative, the more
opportunities there are for things to go wrong.
3. Relative level of uncertainty in project outcome
(low, moderate, high)
Based on design team’s observations and data gathered, analyzed, and modeled to date, this measure provides a
qualitative assessment of the relative level of uncertainty
the project team has in the overall predicted outcomes for
each alternative.
4. Acres of riverine wetland habitat restored at project
completion
Based on predicted local hydrology. Riverine wetlands
depend on bank overflow for their hydrology and provide different functions than slope wetlands. Restoring riverine
wetlands depends on removing fill material from
floodplains. The area of restored riverine wetlands is based
on the predicted 2-year flood event.
5. Acres of slope wetland habitat restored at project
completion
Based on predicted local hydrology on the South Parcel and
restoration actions in the southwest corner of the Triangle
Parcel. Slope wetlands depend on groundwater for their
hydrology and function differently than riverine wetlands. Restoration efforts for slope wetlands include the
modification/re-grading of the man-made pond and drainage
features on the South Parcel.
6. Perimeter to area ratio of largest, contiguous wetland polygon (feet:sq. ft)
This criterion provides a measure of interior core wetland
habitat—the lower the number the more interior core
habitat. Given the existing wetland configuration, the amount of edge habitat on the existing polygons would be
expected to decrease (become less complex) and the interior
core wetland habitat to increase.
7. Montana wetland assessment functional units
Integrates wetland acreage and wetland functionality.
Functional units are based on predicted function scores and
wetland acreages. The four assessment areas (AAs) used
were developed and functional units summed together by
alternative. The AAs used were slope wetlands on South Parcel, Bozeman Creek from I-90 to Osterman’s storage
units, East Gallatin River from L Street to Mill Ditch, and
East Gallatin River-Mill Ditch to Bridger Drive. The largest increase in functional units would come from restoring slope
wetlands on the South Parcel.
8. Extent of ponded open water (acres) This is a feature that has been identified by the community as a desirable amenity. Seasonal and perennial open water
are considered equally at their maximum pool elevation.
9. Total acres of temporary disturbance Risk of invasive/noxious plant species spreading.
10. Acres of restored riparian habitat within 5 years of
project completion Based primarily on active planting efforts on site.
22
Table 6-2. Explanation of Evaluation Criteria (Page 2 of 2)
Evaluation Criteria Comments
11. Increase in the length of streambank where creek is
allowed to freely access its active floodplain (feet)(a)
Measure of hydrologic connectivity between channel and
floodplain based on the predicted 2 year flood event.
12. Increase in the extent of floodplain area (acres)
Measure of hydrologic connectivity of channel and floodplain
and functionality of floodplain. Complements Criterion #11.
Considers total fill removal area in the floodplain of the
East Gallatin River (i.e., 10-year flood event).
13.
Length of East Gallatin River streambanks and
streambed on TPL property that are free of direct human-imposed constraints (feet)
Measure of process constraints. This metric only considers direct constraints, not indirect constraints. For example, at
a particular flow level, a bridge exerts a constraint on a
channel for a few hundred feet up and downstream of its
location. This metric only considers the direct impact of the
physical length of bridge that occurs on either streambank that is constricting the channel. For this reason, it will
underrepresent the actual adverse effect the bridge has on
the creek at higher flow levels. In addition, the effect of the
bridge on flow and the consequences to creek channel and
banks are acknowledged to change at different flows.
14. Estimated cubic yards of excavation
Metric useful for planning and costs. Excess clean soil is assumed to be disposed of in the northwestern portion of the
North Parcel, which is currently lower in elevation
compared to the eastern side.
15. Estimated construction cost (excluding demolition)
Financial metric. Estimate is commensurate with the
conceptual level of design. See Appendix B for information
on assumptions.
16. Estimated demolition cost
Provides detail on financial aspect of project. Developed
from RS means estimates. See Appendix B for information
on assumptions.
17. Estimated cost of building maintenance
Provides detail on financial aspect of project. This
calculation is primarily to show that there is an ongoing cost
associated with keeping the buildings, but the actual cost for maintenance will likely differ substantially from the
numbers used here for comparison. Building maintenance
is based on $1000/building/year for 10 years. The chicken
coop on the South Parcel is not counted.
18. Number of public access points to creek
This is a feature that has been identified by the community
as a desirable amenity. Alternatives 1 and 2 would have
two access points on the North Parcel, no access points on
the South Parcel, and 1 access point on the Triangle Parcel.
(a) The active floodplain is defined as the area subject to flooding during the 2-year flood event.
Table 6-3. Evaluation Criteria and Their Relevance to the Ecological Objectives of the Story Mill Project (Page 1 of 2) Evaluation Criteria General Project Consideration Financial Consideration Ecological Objectives E-1 Hydrologic Connectivity E-2 Remove River Process Constraints E-3 Remove/ Modify Drainage E-4 Demonstrate Improved Water Quality E-5 Restore Native Plant Diversity 1. Probability of meeting ecological objectives (low, moderate, high) X 2. Relative complexity of project; difficulty of implementation (low, moderate, high) X 3. Relative level of uncertainty in project outcome (low, moderate, high) X 4. Acres of riverine wetland habitat restored at project completion X X X 5. Acres of slope wetland habitat restored at project completion X X X 6. Perimeter to area ratio of largest, contiguous wetland polygon (square feet) X X X 7. Montana wetland assessment functional units X X X X X 8. Extent of ponded open water (acres) X X 9. Total acres of temporary disturbance X X X 10. Acres of restored riparian habitat within 5 years of project completion X X X X X 23
Table 6-2. Evalutaion Criteria and Their Relevance to the Ecological Objectives of the Story Mill Project (Page 2 of 2) Evaluation Criteria General Project Consideration Financial Consideration Ecological Objectives E-1 Hydrologic Connectivity E-2 Remove River Process Constraints E-3 Remove/ Modify Drainage E-4 Demonstrate Improved Water Quality E-5 Restore Native Plant Diversity 11. Increase in the length of creek allowed to freely access its active floodplain (feet)(a) X X X 12. Increase in the extent 10 years of floodplain area (acres) X X 13. Percent of streambanks and streambed on TPL property that are free of human-imposed constraints X X 14. Estimated cubic yards of excavation X X 15. Estimated construction cost (excluding demolition) X 16. Estimated demolition cost (2013 dollars) X 17. Estimated cost of building maintenance X 18. Number of access points to creek X Total 6 5 6 5 5 7 6 (a) The active floodplain is defined as the area subject to flooding during the 2-year flood event. 24
25
7.0 RESTORATION DESIGN
This section describes the design process used, assumptions made, and the design
constraints considered in developing the three conceptual restoration alternatives. The three
restoration alternatives are presented in Section 8.0 of this report.
7.1 DESIGN PROCESS
The specific methods used in developing the three conceptual alternatives included the
following:
1. Precipitation analysis
2. Surface water analyses of Bozeman Creek and the East Gallatin River
3. Alluvial groundwater analysis of the South Parcel
4. Water rights analysis
5. Vegetation analysis
6. Projections for wetland establishment
7. Cost estimating.
7.1.1 Precipitation Analysis
Climate data from the Western Regional Climate Center (WRCC) were evaluated for the
Story Mill project site. The closest active, most relevant weather station to the project site is
located at Montana State University (National Climate Data Center COOP Station 241044).
Precipitation averages 19.46 inches per year. Figure 7-1 shows that May and June are the
wettest months of the year and, thus, the time of year when wetlands in the project area are
most likely to be their wettest [Western Regional Climate Center, 2013].
Table 7-1 provides some context for precipitation during the data gathering activities in 2012
and 2013. Average precipitation between April and June typically totals 8.55 inches and
11.68 inches between April and August. Precipitation in April 2012 was above average but
significantly below average in May and June 2012. From April through June 2012,
precipitation was 7.24 inches or approximately 1.31 inches below normal. In 2013, precipitation
in May, and to a lesser extent in June, was above average; though precipitation for April
through June was 8.7 inches or approximately 0.15 inch above average [Western Regional
Climate Center, 2013]. If the entire period from April through August is considered, then both
2012 and 2013 had below average precipitation levels (Table 7-1). Evaporation is high during
these months and totals roughly 15 inches between April 1 and June 30 and 30.5 inches from
April through August (Table 7-1). The high level of evaporation underscores the semi-arid
condition
wetlands
RSI-2274-1
Tab
M
M
M
20
20
Av
Ev
7.1.2 Su
Hydro
performe
provided
ns of the sit
s in the area
13-004
Figu
ble 7-1. Pr
[W
Mean
Minimum
Maximum
012
013
verage Pan
vaporation
urface Wate
ologic and h
ed using gag
by the USG
te and the
.
ure 7-1. Pre
recipitatio
Western Re
April
2.39
0.39
4.67
3.3
0.94
3.34
er Analysis
hydraulic an
ge data from
GS report, M
need for ad
ecipitation G
n Values (
gional Clim
May
3.09
0.73
6.99
2.4
4.31
5.58
nalyses of B
m U.S. Geolog
Methods for
26
dditional sur
Graph for the
(Inches) Fo
mate Cente
June
3.35
0.56
5.49
1.54
3.45
6.03
Bozeman Cr
gical Survey
Estimating
rface water
e Story Mill
or the Stor
er, 2013]
July
1.49
0.10
4.95
1.13
0.71
8.34
reek and th
y (USGS) Ga
Flood Freq
or groundw
Project Area
ry Mill Pro
August
1.37
0.04
3.43
0.58
0.74
7.17
he East Gal
age 0604800
quency in Mo
water to su
a.
oject Area
Total
11.68
1.82
25.53
8.95
10.15
30.46
llatin River
000 and guid
Montana Base
pport
r was
dance
ed on
Data thr
but was
recorded
1981 is a
A stea
backwate
high-reso
existing
that incl
detailed
Figure
restorati
groundw
water ye
May and
during th
below, av
provides
and the
the high
RSI-2274-1
rough Water
located just
23 annual p
also included
ady-state pe
er model HEC
olution LiDA
conditions g
luded chann
description o
es 7-2 and 7
on design
ater was mo
ear (October
d slightly abo
he 2013 wat
verage. This
important c
alluvial grou
(2012) and l
13-005
Year 1998
t downstrea
peak flow ev
d.
eak flow ana
C-RAS version
AR topograp
geometry for
nel cross-sec
of the hydro
7-3 provide s
because w
onitored on t
1, 2011, to
ove average
ter year (Oc
s informatio
context on h
undwater da
low (2013) w
[Parrett and
am of the E
vents primar
alysis was c
n 4.1 [U.S. A
phic data [P
both reache
ctions and l
logic and hy
some context
wetland deli
the sites in 2
September
for the rest
ctober 1, 201
on on cumula
how to interp
ata collected
water flows fo
27
d Johnson, 2
East Gallatin
rily between
completed fo
Army Corps
Photo Scienc
es; this data
longitudinal
ydraulic anal
t for water y
ineation w
2013. As sh
30, 2012) w
of the wate
12, to Septe
ative water
pret the wet
d in 2013.
or an averag
2004]. This
n River/Boz
n 1940 and 1
or both reac
of Engineer
ce, 2013] wa
a was supple
profiles of
lyses is prov
years 2012 a
as complet
own in Figu
was above av
er year. Figu
ember 30, 20
flows for the
land delinea
It indicates
ge year.
s gage is no
eman Creek
1961. A peak
ches using th
rs, 2010]. R
as the basis
emented by
each creek
vided in App
and 2013. T
ted in 201
ure 7-2, disch
verage throu
ure 7-3 show
013) has bee
e 2012 and 2
ation comple
that they g
longer in se
k confluence
k flow event
he standard
ecently acqu
for creatin
field survey
. A much
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This is releva
2, and all
harge in the
ugh the midd
ws that disch
en, at or sli
2013 water y
eted in July
generally br
ervice
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from
d-step
uired,
g the
y data
more
ant to
luvial
2012
dle of
harge
ightly
years
2012
acket
Fig
RSI-2274-1
Fig
Using
the activ
predicted
Peak
461 cfs o
below th
gure 7-2. C
13-006
gure 7-3. C
g the gage tr
ve gage on t
d flow events
Table
flows, as rec
on May 2, 2
he predicted
Cumulative W
Cumulative W
ansfer meth
the East Ga
s are listed i
7-2. Predic
Floo
2
5
1
2
corded on th
2012, and 55
2-year flood
Water Flow f
Water Flow f
hod described
allatin River
in Table 7-2.
cted Flow E
od Event
2-year
5-year
10-year
25-year
he East Gall
58 cfs on Ma
d event. It
28
for the East
for the East
d in Parrett
r below Brid
.
Events For
Disc
(
1
1
1
latin River (
ay 20, 2013
is interestin
Gallatin Riv
Gallatin Riv
and Johnso
dger Creek
r the East G
charge
(cfs)
796
1,190
1,487
1,914
(gage 06048
3. Both of t
ng to note t
ver—Water
ver—Water
on [2004] an
(USGS gage
Gallatin Riv
700) in 2012
these flows a
that the Eas
Year 2012.
Year 2013.
nd gage data
e 06048700)
ver
2 and 2013,
are substan
st Gallatin R
from
), the
were
ntially
River
29
flows of late May 2008 (1,900 cfs) and late May 2011 (1,450 cfs) roughly correspond to the
predicted 25-year and 10-year flood events, respectively.
7.1.3 Alluvial Groundwater Analysis
Alluvial groundwater data were collected at 15 wells located around the South Parcel, as
shown in Figure 7-4, during the 2013 growing season. This data was evaluated in terms of the
depth to water below the ground surface as well as its absolute elevation above mean sea level,
which are illustrated in Figure 7-5. The evaluation of the depth below ground surface provides
information relevant to wetland establishment and projected future establishment. An
evaluation of groundwater elevations above mean sea level (e.g., 4,729 feet) provides
information about the direction and gradient of groundwater flow.
An analysis of the groundwater levels, when compared to the discharge of the East Gallatin
River (Figure 7-5), shows that the groundwater found on the South Parcel fluctuates seasonally
and episodically. Alluvial groundwater levels on the South Parcel are highest during the spring
and decrease over the summer. In 2013, the highest groundwater levels were observed on
May 19 and corresponded to the highest recorded discharge levels for the East Gallatin River,
which occurred on May 20. Groundwater levels generally decreased over the rest of the
summer, closely matching flows in the creeks, and were the lowest at the end of August. In
mid-September, as irrigation season came to an end, both flows in the creeks and the
groundwater elevations increased on the South Parcel. Groundwater was also observed to
increase in response to rainfall events and corresponding increases in discharge in the East
Gallatin River on June 14 and June 29.
Alluvial groundwater levels were also related to actual surface elevations and then analyzed
using a triangulated irregular network (TIN) in a geographic information system (GIS). This
analysis showed that groundwater is generally flowing from south to north across the South
Parcel.
Conclusions from this analysis of groundwater relevant to restoration design on the South
Parcel include the following:
The hydrology of wetlands found on the interior portion of the South Parcel is directly
linked to discharge in Bozeman Creek and the East Gallatin River.
Shallow, alluvial groundwater flows from south to north across the project area.
Wetlands on the South Parcel will be seasonally wettest between mid-May and mid-June;
therefore, the design elevation for groundwater should be based on a high groundwater
elevation. Elevations of groundwater measured on May 19, 2013, were used in the
restoration design.
RSI-2274-1
Figur
13-007
re 7-4. Grouundwater Well Locations
30
s on the Souuth Parcel off the Story MMill Project A
Area.
Figure 7-5. Depth to Groundwater and Discharge of the East Gallatin River (below Bridger Creek) at the Story Mill Project Site (note that groundwater levels were not monitored continuously, and the lines between groundwater sampling dates are included to show trends in groundwater; actual groundwater levels likely fluctuated more frequently and more drastically than depicted). RSI-2274-13-008
31 0100200300400500600‐70.00‐60.00‐50.00‐40.00‐30.00‐20.00‐10.000.0030‐Apr‐137‐May‐1314‐May‐1321‐May‐1328‐May‐134‐Jun‐1311‐Jun‐1318‐Jun‐1325‐Jun‐132‐Jul‐139‐Jul‐1316‐Jul‐1323‐Jul‐1330‐Jul‐136‐Aug‐1313‐Aug‐1320‐Aug‐1327‐Aug‐133‐Sep‐1310‐Sep‐1317‐Sep‐1324‐Sep‐13Discharge (cfs)Depth to Groundwater (inches)TPL‐GW‐01TPL‐GW‐02TPL‐GW‐03TPL‐GW‐04TPL‐GW‐05TPL‐GW‐06TPL‐GW‐07TPL‐GW‐08TPL‐GW‐09TPL‐GW‐10TPL‐GW‐11TPL‐GW‐12TPL‐GW‐13TPL‐GW‐14TPL‐GW‐15Discharge (cfs)
32
Precipitation levels were high in May 2013, but the discharge of the creeks did not reach
the predicted 2-year flood event, which suggests that use of the May 19, 2013,
groundwater levels is both reasonable and conservative.
7.1.4 Water Rights Analysis
A Mr. Steve Cook with the Montana Department of Natural Resources Conservation staff in
Bozeman was consulted with regard to water rights for the project area. No surface water
rights or points of diversion are associated with any of the parcels in the Story Mill project area.
There is one groundwater right from 1983 for the South Parcel (Water Right ID: 41H 49720 00).
It allows for a flow rate of 16 gallons per minute, or 5.41 acre-feet per year, and the irrigation of
0.5 acre of land. According to their records there are three wells on the North Parcel, but none
of them have water rights associated with them. There is no water right associated with the
pond. The drainage ditch on the property is not a designated ditch and so appears to be a true
drainage ditch that is not used for irrigation. For this reason, if the ditch is filled no water
rights would be affected.
According to Montana State water law, if a site was historically a wetland and is being
restored to a wetland, no water right is needed. The Story Mill project area occurs just
upstream from the confluence of Bozeman Creek and the East Gallatin River. Just by its
topographic position in the landscape one would expect this area to be extremely wet. The
South Parcel is in fact very wet as evidenced by the high groundwater table expressed at the
pond and recorded in the 15 groundwater wells installed across the site, the need for a drainage
ditch that crosses the property, and the several acres of existing wetlands currently found on
the site. Furthermore, the Gallatin Local Water Quality District’s 2004 report on wetlands and
riparian resources in the Gallatin Valley indicate that the Story Mill project area was a wetland
riparian area (English and Baker 2004). Based on this information it appears that restoration
actions will not require a water right.
7.1.5 Vegetation Analysis
RESPEC’s restoration design process considered several sources of information to better
understand the composition and condition of vegetation currently occurring on the site. These
sources of information included the following:
Interpretation of historic aerial photography to better understand historic land uses and
land management of the site
The wetland delineation of the site completed by River Design Group Inc. in July 2012
[River Design Group Inc., 2012]
The Story Mill Vegetation Management Plan [TerraQuatic, 2013]
On-site field investigations in July and August 2013.
33
Native vegetation occurring within the project area has been highly disturbed by historic
agricultural activities, such as land clearing and haying. Use of the site by livestock may have
also occurred, but in a limited capacity. Current conditions of the vegetation occurring on the
site reflect years of neglect and poor land management. Much of the site is dominated by state-
listed noxious weeds, such as common tansy and Canada thistle. Many of the wetland areas
found on site are dominated by invasive species, such as reed canarygrass, Garrison creeping
foxtail, or broadleaf cattail. Smooth brome and other introduced pasture grasses are also
common.
There are five general vegetation communities on the Story Mill project site: wetlands,
riparian areas, upland herbaceous areas, an aspen forest, and the farmstead area (Appendix B).
Plant species observed in each of these areas, and their relative abundance in the project area,
are listed in Appendix B.
The design approach toward vegetation and revegetation on the site was to include the
following:
Minimize disturbances to the extent practicable
Maintain existing mature woody vegetation, such as cottonwoods in riparian areas and
around the farm house
Use native plant species able to compete with existing vegetation
Ongoing irrigation and maintenance would not be possible, so the use of containerized
plant material outside of wetland areas would not be possible
Noxious weed control would continue to be implemented on the site
Develop native seed mixes based on predicted water regimes (i.e., upland, riparian, and
wetland) that use commercially available plant seed for species occurring on site or in the
project vicinity.
7.1.6 Projected Wetland Establishment
Proposed restoration actions in the conceptual alternatives attempt to maximize wetland
development, while adhering to specific design constraints and criteria, included not allowing
the adjacent landowners’ properties to become wetter than they already are.
Establishing new wetland areas was projected based on these restoration actions, as well as
several pieces of information that integrate climatic, hydrologic, vegetation, physical soil
information, and the site’s pre-settlement/ecological potential. Recorded groundwater
elevations and modeled gradients on the South Parcel for May 19, 2013, include the following:
Depth to groundwater below ground surface on the South Parcel in May and June 2013
34
Existing wetland footprint as determined in July 2012 [River Design Group Inc., 2012]
Field observations of hydrophytic vegetation outside of the wetland boundaries,
suggesting that either the area was wetter before, or that it is wet enough to sustain a
limited population of hydrophytic vegetation. Either condition is favorable for wetland
reestablishment
Soil texture (clay, silty clay loam, or coarser) and ability for capillary rise in the soils
Predicted 2-year flood elevations of Bozeman Creek and the East Gallatin River.
This information was evaluated and where surface water occurred, or shallow groundwater was
predicted to be within 12 inches of the soil surface, for 14 consecutive days or longer between
May and October (the growing season), the area was classified as restored wetland. Grading
areas outside of the existing drainage ditch were designed to intercept shallow groundwater.
Based on the data collected to date, filling the drainage ditch is expected to raise local alluvial
groundwater levels during the spring runoff season. In addition, the planting of willow cuttings
can also help to raise alluvial groundwater levels and make the site more wet through
evapotranspiration pumping of water by the plants.
7.1.7 Cost Estimating
Unit costs were obtained from RSMeans Site Work and Landscape Cost Data for 2012
[RSMeans, 2012], RESPEC local and regional experience, the Montana Department of
Transportation (MDT) average bid prices 2012, Federal Highway Administration (FHWA) bid
documents, and from vendors. Subtotal costs were rounded up to the nearest $100.
Mobilization was assumed to be 20 percent of the total cost; a 10 percent contingency was
included for items that were overlooked or underpriced; and a 1-year, 3 percent inflationary
value was included in the totals.
It is important to understand that there are, typically, multiple options available for
excavation and other earthwork that will vary by contractor based on the equipment that they
own or are able to acquire and use on the project The methods assumed for use in the
conceptual cost estimates are one reasonable approach with associated representative costs.
Every effort was made to provide realistic costs; however, there are many assumptions that
are required to be able to make a cost estimate. These assumptions are briefly covered in
Section 7.2 and are provided in more detail in Appendix C.
7.2 Assumptions
A complete list of all of the assumptions used in the development of the conceptual
alternatives is provided in Appendix C. Assumptions common to all three alternatives are
listed below.
35
Global Assumptions
1. Unit costs were developed from a variety of standard cost-estimating sources including:
RSMeans cost data (national cost data base), MDT unit prices, specific quotes from local
and regional suppliers/vendors, and cost information from other similar projects
maintained by local RESPEC staff.
2. Project implementation would incorporate standard contracting format and would be
conducted during a favorable construction window.
3. The following buffer distances would be maintained for buried utility lines (i.e., gas,
sewer, and water):
Utility Horizontal Buffer Vertical Buffer
Natural Gas 20 feet from line No disturbance of existing ground
surface (NOTE: This was changed to 25’ from line
for the Selected Alternative).
Sanitary Sewer 5 feet from line Maintain minimum 5 feet of cover
Water 5 feet from line Maintain minimum 6.5 feet of cover
4. Overhead electric power poles would maintain the existing ground elevation at their
base and extend a minimum of 5 feet in any direction from the base. Any grading
outside of this circle would only occur at a 5H:1V slope or less.
5. Building/structure removal would include all above-ground portions of the structures as
well as foundations, slabs-on-grade, and bridge abutments. No asbestos or lead paint is
present in the buildings.
6. Excavated material generated from on-site grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
Excess, excavated soil material would be disposed of on site, primarily within the North
Parcel.
7. No hazardous materials occur on site.
7.3 Design Constraints
The following constraints were considered during the restoration design:
The East Griffin Road and bridge over the East Gallatin River cannot be moved or
modified
The Osterman property and the Sebena property should not become more wet as a
consequence of wetland development on the South Parcel
Restoration activities cannot occur on the Bryant Street right-of-way (South Parcel)
36
No disturbance within 25 feet of the natural gas pipeline (South Parcel)
No disturbance within 5 feet of the sewer pipelines (South Parcel)
No disturbance within 5 feet of the water pipelines (South Parcel)
Overhead electric lines occur on the North Parcel
There are no surface water rights associated for the property
The Story Mill Spur Trail occurs along the railroad right of way, which cannot be
modified; this includes the railroad bridge over the East Gallatin River
Maintain mature cottonwood trees in the vicinity of the farmhouse
Maintain mature cottonwoods along the East Gallatin River on the North Parcel
Invasive plants, such as reed canarygrass, Garrison creeping foxtail, and cattails, may
limit the extent to which native vegetation is able to become established
The watershed is becoming more urbanized, which could continue to exacerbate the
timing, magnitude, and frequency of discharge in response to snowmelt and rain events
Non-point-source pollution will continue to enter the project site from upstream sources.
37
8.0 RESTORATION ALTERNATIVES
The three restoration alternatives are generally described in Chapter 5.0 of this report.
These three alternatives progress from the most extensive restoration activities in
(Alternative 1–Ecological Restoration I), to more modest restoration activities (Alternative 2–
Ecological Restoration II), to a minimum level of planned restoration activities (Alternative 3–
Passive Restoration). These three alternatives are compared and contrasted in Table 8-1
through the use of an evaluation matrix with 18 different metrics (Chapter 6.0 also provides
descriptions of the metrics). A summary costing table is provided in Table 8-2, and figures are
included in Appendix D.
38
Table 8-1. Evaluation Matrix for Three Conceptual Restoration Design Alternatives
Proposed For the Story Mill Project Area
Evaluation Criteria
Alternative
Restoration I Restoration II Passive
Restoration
Selected
Alternative
1. Probability of meeting ecological
objectives (low, moderate, high) High High–Moderate Moderate–
Low High
2. Relative complexity of project; difficulty of
implementation (low, moderate, high) Moderate Moderate Low Moderate
3. Relative level of uncertainty in project
outcome (low, moderate, high) Low–Moderate Low–Moderate Low Low–
Moderate
4. Acres of riverine wetland habitat restored
at project completion (acres) 1.4 0.6 0 2.0
5. Acres of slope wetland habitat restored at
project completion (acres) 6.7 6.6 0 6.0
6.
Perimeter-area ratio of largest,
contiguous wetland polygon (feet:square
feet)
0.01 0.015 0.028 0.01
7. Montana Wetland Assessment functional
units 110 105 65 109
8. Extent of ponded open water (acres) 0.2 0.03 0.5 0.5
9. Total acres of temporary disturbance
(acres) 11.4 8.7 1.4 11.4
10. Acres of restored riparian habitat within
5 years of project completion (acres) 5.4 3.9 0 2.8
11.
Increase in the length of streambank
where both creeks are allowed to freely
access their active floodplains (feet)(a)
1,360 830 0 1,360
12. Increase in the extent of floodplain area
(acres) 5.0 1.5 0 2.9
13.
Length of East Gallatin River
streambanks and streambed on TPL
property that are free of direct human-
imposed constraints (feet)
2,600
(100%) 2,580 1,030 2,580
14. Estimated cubic yards of excavation
(cubic yards) 28,410 10,410 1,840 20,250
15. Estimated construction cost (excluding
demolition) $485,800 $331,500 $102,300 $445,000
16. Estimated demolition cost $248,100 $139,200 $139,200 $139,200
17. Estimated cost of building maintenance $10,000 $30,000 $80,000 $30,000
18. Number of public access points to creek 3 3 1 3
(a) The active floodplain is defined as the area subject to flooding during the 2-year flood event.
39
Table 8-2. Summary Costs of Restoration Design Elements at the Story Mill
Project Area (Estimated by M. Johnson and Reviewed by
M. Rotar and R. McEldowney) (Page 1 of 2)
Story Mill Restoration Alternatives—Conceptual Cost Estimate by Parcel and Alternative
Restoration I
($)
Restoration II
($)
Passive
Restoration
($)
Selected
Alternative
North Parcel
Expand East Gallatin River floodplain,
excavate fill 76,800 33,700 0 79,400*
Pedestrian river access 3,700 3,700 3,700 3,700
Restore wetland and vegetative diversity(a) 0 0 0 0
River corridor cleanup—remove riprap and
trash 5,400 5,400 5,400 5,400
North Parcel Subtotal 85,900 42,800 3,700 88,500
South Parcel
Remove farm buildings 84,600 84,600 84,600 84,600
Keep driveway up to bend for trail 1,100 1,100 1,100 1,100
Reconfigure pond/ditch(b) 0 0 0 0
Excavate Bozeman Creek floodplain, expand
water-quality potential 27,600 0 0 32,600*
Restore wetland and vegetative diversity 112,400 108,100 1,100 112,400
Pedestrian wetland observation trails 14,700 14,700 0 14,700
Multiuse connector trail 17,000 17,000 17,000 17,000
River corridor cleanup—remove riprap and trash 3,100 0 0 3,100
South Parcel Subtotal 260,500 225,500 103,800 265,500
Triangle Parcel
Remove garage 20,000 20,000 20,000 20,000
Remove slaughterhouse buildings 81,900 0 0 0
Remove bridge 7,300 0 0 0
Pedestrian river access (convert driveway) 1,900 1,900 0 1,900
Truncate driveway at house(b) 0 0 0 0
Expand East Gallatin floodplain, excavate fill,
expand water-quality potential 80,800 18,200 0 17,800**
Restore wetland and vegetative diversity 9,900 41,900 54,000 41,900
40
Table 8-2. Summary Costs of Restoration Design Elements at the Story Mill
Project Area (Estimated by M. Johnson and Reviewed by
M. Rotar and R. McEldowney) (Page 2 of 2)
Story Mill Restoration Alternatives—Conceptual Cost Estimate by Parcel and Alternative
Restoration I
($)
Restoration II
($)
Passive Restoration
($)
Selected
Alternative
Triangle Parcel (Continued)
River corridor cleanup—remove riprap and
trash 3,500 3,500 0 3,500
Triangle Parcel Subtotal 205,300 85,500 74,000 85,100
Alternative Subtotal 551,700 353,800 181,500 439,100
Mobilization—General Requirements (20%) 110,400 70,800 36,300 87,900
10% Contingency 55,200 35,400 18,200 44,000
1-Year Inflation (3%) 16,600 10,700 5,500 13,200
Conceptual Construction Cost Estimate 733,900 470,700 241,500 584,200
(a) Item included within expand East Gallatin River floodplain category
(b) Item included within restore wetland and vegetative diversity category.
* Change in cost estimate from Alternative 1 is caused by additional excavation to maximize the area of the 2-
yr floodplain, additional plantings of willow cuttings, wetland seed (versus riparian seed).
** Change in cost estimate from Alternative 2 is caused by a reduction in floodplain excavation on right bank, bank wrap on right bank, maximization of 2 yr floodplain on left bank, additional plantings of willow
cuttings, wetland seed (versus riparian seed).
41
9.0 SELECTED ALTERNATIVE
The Trust for Public Land reviewed the three conceptual alternatives and selected design
elements that provided the most overall benefit for the proposed park, in consideration of the
stated goals, previous stakeholder and community input, and budgetary restrictions. The
resulting combination of design elements is termed the ‘selected alternative’ though it is
comprised of design elements from the conceptual alternatives, as well as some new or ‘revised’
design elements that were developed in response to the alternative conceptual designs. The
design elements of the selected alternative are summarized and compared to the three
conceptual alternatives in Tables 5-1, 8-1, and 8-2 and depicted in figures provided in Appendix
E.
The Selected Alternative is a combination of Alternatives 1 and 2, which will maximize
benefits to water quality, wetlands, and streams. As proposed, the Selected Alternative will
more than double the amount of wetlands found on the site, adding roughly 8.0 acres of restored
wetlands to the roughly 7.5 acres of wetlands currently occurring on the three parcels that
make up the project area. Greater than 80% of these wetlands would be restored on the South
Parcel through a combination of raising of seasonal groundwater elevations by re-grading the
existing drainage ditch, demolition and removal of farm buildings and excavation of associated
fill on the east and west sides of the farm compound, and creation of a backwater slough off of
Bozeman Creek.
Vegetative diversity of the site is improved through native seeding and plantings,
restoration of site hydrology, and ongoing weed control efforts. The Selected Alternative would
also restore natural fluvial processes (i.e., erosion and deposition) along 2,580 feet of the East
Gallatin River through the removal of sidewalk rubble used as makeshift riprap, and the
removal of old machinery and trash embedded in the channel and streambanks.
The Selected Alternative maintains the extent of the current pond on the South Parcel, but
naturalizes the shoreline through grading and willow plantings. The potential for surface water
quality improvements to Bozeman Creek is maximized through the creation of a new 1 acre
backwater slough that will promote the deposition and uptake of nutrients found in creek
waters. Surface water quality improvements are also proposed for the East Gallatin River on
the Triangle Parcel and on the North Parcel. On these parcels the East Gallatin River is fairly
incised and does not have as much access to its floodplain as is desirable. The solution proposed
by the Selected Alternative is to create roughly 2.9 acres of new floodplain area, of which
roughly 70% would be wetlands and 30% riparian forest. In addition, three new public access
points to the East Gallatin River are proposed under the Selected Alternative.
Construction of the Selected Alternative would require the excavation of over 20,000 cubic
yards of fill material. This material is planned to be repurposed and used as fill in a currently
42
topographically depressed area of the North Parcel. This will minimize haul costs and assist in
the construction of other park amenities, such as a parking lot. The projected construction cost
for restoration actions under the Selected Alternative is $584,200. This cost includes the
demolition and removal of the farm buildings found on the South Parcel and the storage garage
on the Triangle Parcel, but does not include removal of the old slaughterhouse buildings or
bridge found on the Triangle Parcel.
Specific restoration design elements of the Selected Alternative include:
North Parcel (see figure on page E-3): Historically placed fill material would be removed
from the area north of the East Gallatin River channel to restore connectivity between
the channel and its’ floodplain. The target elevation for the new floodplain is the
predicted 2-year flood elevation; meaning that this area would be expected to flood
roughly 5 out of every 10 years. Willow cuttings would be planted in the new floodplain
area in clusters to mimic naturally occurring willows in the vicinity and to increase
surface roughness which helps to slow floodwaters; promotes deposition, infiltration, and
bio-geochemical processing; and thereby improves water quality. Existing mature
vegetation is preserved to the extent that it can be. Three gaps would be created in the
existing bank to reconnect the channel with its new floodplain and would facilitate flood
flow into the new floodplain. These gaps are positioned in existing openings between
mature cottonwood trees in order to minimize disturbances. The 2-year floodplain is
designed to slope up to the existing grade at a gentle 5 feet horizontal to 1 foot vertical
gradient. This slope would be vegetated with a native riparian seed mix of grasses, forbs
and shrubs such as chokecherry and snowberry. Two access points constructed of
geotextile grids would be installed to allow access to the creek itself.
South Parcel (see figures on pages E-4 and E-5): There are numerous restoration
components proposed for the South Parcel that more than double the current wetland
acreage found there; increasing wetland acreage from roughly 5.5 acres to 12.2 acres.
Proposed restoration actions on the South Parcel are dominated by three key actions –
demolition and removal of the farm buildings, filling and grading of the drainage ditch
that traverses the site from the pond to the East Gallatin River, and construction of a
backwater slough off of Bozeman Creek.
Beginning in the southwest portion of the South Parcel, additional floodplain and
wetland area (~0.7 acre) along Bozeman Creek would be created. Termed the Bozeman
Creek slough, this area would be excavated to the predicted 2 year floodplain elevation.
Hydraulic modeling of these lower floodplain elevations in this area indicates that a
backwater effect will be created during higher flow levels. Interception of shallow
groundwater should also be expected. The result will be additional wetland area
interacting with surface water from Bozeman Creek. This interaction is expected to help
improve water quality in Bozeman Creek, particularly during the growing season (May –
43
Oct). The seeding of native wetland grasses and sedges, and planting of native willow
cuttings found in the vicinity will finish the site.
Moving more into the south-central portion of the site, the existing pond will be
reconfigured to have a more natural looking shoreline, and to blend seamlessly with the
surrounding landscape through the redistribution of fill material excavated from the
pond. Seeding and willow plantings will help the site recover from earth moving
activities and for it to blend in with adjacent, undisturbed areas. Seasonal water levels
in the interior portion of site north of the pond and north of the farm buildings will be
restored through the filling and re-grading of the existing drainage ditch. To maintain
existing hydrologic conditions on the Sebena Property the filling of the drainage ditch
north of the pond will not extend all the way to the property line.
In the central portion of the South Parcel the farm buildings will be demolished and
removed. The large cottonwood trees found there would be preserved to provide shade
for future park goers and to diversify habitat on the parcel. Excavation and grading on
the edges of the farm compound, in conjunction with the filling of the drainage ditch, will
establish even more wetland acreage in the central portion of the parcel.
Filling and grading of the drainage ditch north of the farm buildings is expected to raise
the local water table and promote additional wetland restoration. The majority of the
existing driveway will remain in place to restrict water movement off of the South Parcel
to the west, and help to focus water movement northward within the South Parcel.
Finally, a 0.55 mile long wetland observation trail is proposed that would connect to a
0.25 mile long multi-use connector trail that connects the existing Story Mill Spur Trail
to Bond Street and Gold Ave. Boardwalks are planned where the trails cross wetland
areas.
Triangle Parcel (see figure on page E-6): Restoration actions proposed for the Triangle
Parcel include the removal of the parking/storage garage on the east side of the East
Gallatin River. The historic slaughterhouse buildings on the west side of the creek
would be preserved. Gravel and fill material used in the parking lots and roads found on
either side of the creek would be removed to a depth of 1-foot and replaced with topsoil
and then drill seeded with native upland grass and forb species. In the western-most
area of the Triangle Parcel a new riparian area is proposed to be constructed between
the existing wetland to the west and the newly rehabilitated upland area to the east,
providing a natural transition between these two habitat types.
With the exception of the bridge leading to the slaughterhouse, riprap and other man-
made constraints would be removed from the streambanks and channel of the East
Gallatin River. The 2-year floodplain on the west side of the creek (left bank) would be
increased by 0.23 acres and planted with willow cuttings; providing additional
44
opportunity for surface water quality improvement of the East Gallatin River during
frequent flood events. As in other areas, willow cuttings would be planted in clumps and
drifts to facilitate the development of floodplain function and a natural aesthetic. The
right bank west of the storage garage would also be restored by removing the existing
sidewalk riprap, laying the steep streambank back to the northeast, and creating a new
bank at the predicted 2-year flood elevation with a narrow floodplain bench. These
actions strike a balance between restoring natural functions of the creek in this area,
while minimizing costs.
Overall the Selected Alternative would achieve the ecological restoration goal and five
restoration objectives developed for the site. Table 9-1 summarizes the relative degree that the
proposed restoration actions of the Selected Alternative achieve stated ecological restoration
objectives.
Table 9-1. Relative degree* Selected Alternative restoration actions proposed for
each parcel accomplish restoration objectives.
North
Parcel
South
Parcel
Triangle
Parcel
E-1
Provide hydrologic connectivity between
stream floodplain and wetlands to
maximize riverine and wetlands habitat
diversity.
+++ +++ ++
E-2
Remove river process constraints and
non-natural features to the extent
possible in the context of land ownership
and access.
+++ +++ ++
E-3
Remove or modify drainage and
excavated features that disrupt and
diminish groundwater-dependent
wetland extent and functioning to restore
wetland functions to the extent site
constraints allow.
Not
applicable +++ Not
applicable
E-4
Demonstrate improved water quality
(temperature, nutrients and sediment
measures).
+++ +++ ++
E-5
Restore native plant diversity (upland,
wetland and riparian communities) and
minimize invasive plants.
+++ +++ ++
*Relative degree of restoration actions: +++ = highest; + = lowest
45
10.0 REFERENCES
English, A., and C. Baker, 2004. Wetland and Riparian Resource Assessment of the Gallatin
Valley and Bozeman Creek Watershed, Gallatin County, Montana. Prepared by the Gallatin
Local Water Quality District for the Montana Department of Environmental Quality. June
2004.
Lesica, P., 2012. Manual of Montana Vascular Plants, Brit Press, Fort Worth, Texas.
Lichvar R., C. Melvin, M Butterwick, and W. Kirchner, 2012. The National Wetland Plant
List: Indicator Rating Definitions, prepared by the U.S. Army Corps of Engineers, Engineer
Research and Development Center, Cold Regions Research and Engineering Laboratory,
Washington, DC.
Natural Resources Conservation Service (NRCS), 2002. Climate data for WETS Station :
BOZEMAN MONTANA ST UNIV, MT1044 Creation Date: 09/06/2002. State
FIPS/County(FIPS): 30031. Start yr. - 1971 End yr. – 2000. Available URL:
http://www.wcc.nrcs.usda.gov/ftpref/support/climate/wetlands/mt/30031.txt.
Parrett, C. and D. R. Johnson, 2004. Methods for Estimating Flood Frequency in
Montana Based on Data Through Water Year 1998, Water-Resources Investigations Report
(WRIR) 03-4308, prepared by U.S. Geological Survey, Helena, MT.
Photo Science Inc., 2013. Gallatin River and Bozeman Creek, MT LIDAR data acquisition
and processing. April 18, 2013. Lexington, KY. 9 p.
RESPEC, 2013. Summary of Hydrologic and Hydraulic Analyses Completed for the Story Mill
Ecological Restoration Project, Technical Memorandum. Prepared by RESPEC, Bozeman, MT,
for M. Pope, The Trust for Public Land, Bozeman, MT, October 6.
River Design Group, Inc., 2012. Wetland Delineation Report–Story Mill Project Site,
Bozeman, Montana, prepared by the River Design Group, Inc., Whitefish, MT, for The Trust
for Public Land, Bozeman, MT.
RSMeans, 2012. Site Work & Landscape Cost Data. Norwell, MA.
TerraQuatic, 2013. Story Mill Vegetation Management Plan, prepared by TerraQuatic,
Bozeman, MT, for The Trust for Public Land, Bozeman, MT.
U.S. Army Corps of Engineers, 2010. Hydrologic Engineering Center–River Analysis
System, version 4.1, U.S. Army Corps of Engineers, Davis, CA.
Western Regional Climate Center, 2013. “Bozeman Montana ST UNIV, Montana (241044)
Period of Record Monthly Climate Summary,” wrcc.dri.edu, retrieved July 2013, from
http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?mt1044
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A-1
APPENDIX A
HYDROLOGIC AND HYDRAULIC ANALYSES FOR STORY MILL
RESTORATION PROJECT
A-2
A-3
A-4
A-5
A-6
A-7
A-8
A-9
A-10
A-11
A-12
A-13
A-14
A-15
A-16
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B-1
APPENDIX B
PLANT SPECIES IN THE STORY MILL PROJECT AREA
B-2
B-3 Table B-1. Plant Species Observed on the Story Mill Project Area (Surveyed by Ms. Andrea Pipp on July 23, 2013) (Page 1 of 10) Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South TREES Acer species maple seedlings unknown ‐‐‐ IF Seedlings of less than one foot observed in several places, but mature tree/shrub not observed. Fraxinus pennsylvanica green ash native FAC IF Juniperus scopulorum Rocky Mountain juniper native ‐‐‐ VC Probably a couple of juniper varieties or species are present at homestead. Malus species crab apple unknown ‐‐‐ IF Probably a horticultural species. Populus balsamifera cottonwood native FAC VC VC VC VC Hybrids may be present. Populus tremuloides quaking aspen native FACU IF F IF VC In Upland Herbaceous‐Parcel 3 it is found along Story Mill Road. Pseudotsuga menziesii Douglas‐fir native FACU F Salix fragilis weeping willow exotic FAC VC VC VC VC May be hybrids with S. alba. Sorbus species mountain ash unknown ‐‐‐ IF Probably a horticultural species. SHRUBS Alnus incana speckled alder native FACW VC F
B-4 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Cornus sericea syn. C. alba, C. stolonifera red‐osier dogwood native FACW F F F IF Population seems suppressed. Lonicera species honeysuckle unknown ‐‐‐ F Probably a horticultural species. Prunus virginiana chokecherry native FACU IF IF VC VC VC IF Species or variety at homestead may differ from other parcels. In Upland Herbaceous‐Parcel 3 it forms a row at the southeast boundary. Rhus trilobata skunkbush sumac native ‐‐‐ IF Ribes aureum golden currant native FAC F F IF Ribes species currant unknown ‐‐‐ F F IF Rosa acicularis prickly rose native FACU IF Rosa woodsii Woods' rose native FACU IF F F IF F Salix boothii Booth's willow native FACW IF IF VC VC IF F Salix exigua streamside or coyote willow native FACW F VC IF IF F VC in southwest portion of Parcel 1. Salix lutea yellow willow native OBL F F Symphoricarpos occidentalis western snowberry native UPL F F F F F F Syringa species Lilac exotic ‐‐‐ VC FORBS Achillea millefolium common native FACU IF
B-5 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South yarrow Arctium minus lesser burdock exotic UPL IF F IF F F Asteraceae Aster Family unknown ‐‐‐ IF Possibly a horticultural species. Berteroa incana hoary alyssum exotic (State noxious) ‐‐‐ IF F IF IF Brassicaceae Mustard Family unknown ‐‐‐ IF Capsella bursa‐pastoris Shepherd’s purse exotic FACU IF Carduus nutans musk thistle exotic (County noxious) UPL F Primarily in the driveway. Centaurea maculosa spotted knapweed exotic (State noxious) ‐‐‐ F F Cirsium arvense Canada thistle exotic (State noxious) FAC VC VC VC VC VC F Cirsium vulgare bull thistle exotic FACU IF IF IF IF Conium maculatum poison hemlock exotic (State noxious) FAC IF IF Border of upland and riparian habitats. Cynoglossum officinale hound's‐tongue exotic (State noxious) FACU F F F F IF Epilobium ciliatum fringed willowherb native FACW IF
B-6 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Euphorbia esula sulfur cinquefoil exotic (State noxious) ‐‐‐ F IF IF Only in southeastern portion of Riparian Parcel 1. Galium aparine stickywilly native FACU IF IF Geum macrophyllum large‐leaved avens native FAC IF Glycyrrhiza lepidota licorice‐root native FAC F IF Heracleum lanatum syn. H. maximum cow parsnip native FAC IF IF F Hesperis matronalis dames rocket; mother‐of‐the‐evening exotic FACU IF Iva xanthiifolia syn. Cyclachaena xanthiifolia carelessweed native FAC IF Lactuca serriola prickly lettuce exotic FACU IF IF Lamiaceae Mint Family unknown ‐‐‐ IF Possibly a horticultural species. Lemna minor duckweed native OBL F Lepidium draba syn. Cardaria draba whitetop exotic (State noxious) ‐‐‐ F Leucanthemum vulgare syn. Chrysanthemum leucanthemum oxeye daisy exotic (State noxious) FACU IF IF F Linaria vulgaris yellow toadflax exotic (State noxious) ‐‐‐ F F
B-7 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Lotus corniculatus bird's ‐foot trefoil exotic FAC F Occurs along driveway bordering Upland Herbaceous Parcel 1. Lysimachia ciliata fringed loosestrife native FACW IF IF Matricaria matricarioides syn. M. discoidea pineapple weed exotic FACU IF Medicago lupulina black medick exotic FACU IF IF Melilotus officinale yellow sweet clover exotic FACU IF IF IF Mentha arvensis field mint; American wild mint native FACW IF F Plantago major common plantain exotic FAC IF Polygonum (aviculare) (prostrate) knotweed exotic (FAC) IF IF Near wetland/upland edge Polygonum amphibium syn. Persicaria amphibia water smartweed native OBL VC F Potentilla anserina syn. Argentina anserina common silverweed native OBL F IF Ranunculus acris tall buttercup exotic (State noxious) FAC IF IF IF IF Would be good to get a 2nd opinion on species.
B-8 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Ranunculus sceleratus celery‐leaved buttercup native OBL IF Rorippa curvipes bluntleaf yellowcress native FACW IF Rumex crispus curly dock exotic FAC IF IF IF Rumex fueginus syn. R. maritimus golden dock native FACW IF Silene latifolia syn. Lychnis alba white campion exotic ‐‐‐ IF IF Occurs on bank where overstory vegetation has been removed. Silene vulgaris maidenstears exotic ‐‐‐ IF Sisymbium species mustard exotic ‐‐‐ IF IF IF Solanum dulcamara climbing nightshade exotic FAC IF Solidago canadensis Canada goldenrod native FACU IF Sonchus species exotic ‐‐‐ IF Tanacetum vulgare common tansy exotic (State noxious) FACU VC VC VC VC VC VC F IF IF Taraxacum officinale common dandelion exotic FACU F F VC VC F Thlaspi arvense field pennycress exotic UPL IF IF Tragopogon dubois western salsify exotic ‐‐‐ IF IF IF
B-9 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Trifolium repens white clover exotic FAC IF Urtica dioica stinging nettle native FAC IF IF Verbascum thapsus common mullein exotic FACU IF IF Verbena bracteata prostrate or carpet vervain exotic FAC IF Occurs in driveway bordering Upland Herbaceous Parcel 1 and in Parcel 3. GRASS / GRASS‐LIKE Agropyron repens syn. Elymus repens quack grass exotic FAC VC VC VC VC VC VC VC IF F Agrostis stolonifera redtop exotic FAC VC VC VC VC VC F Alopecurus arundinaceus creeping meadow foxtail exotic FAC VC VC VC VC VC Alopecurus pratensis field meadow foxtail exotic FAC Suspected to occur, but not observed on July 23, 2013. Bromus (carinatus) syn. B. (marginatus) California or mountain brome native ‐‐‐ F F Bromus inermis smooth brome exotic FAC VC VC VC VC VC VC Bromus japonicus Japanese brome exotic ‐‐‐ IF IF near wetland/upland boundary Bromus tectorum cheatgrass exotic (State regulated) ‐‐‐ F
B-10 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Calamagrostis stricta slimstem reedgrass native FACW F Carex aquatilis water sedge native OBL IF Carex microptera small‐wing sedge native FACU IF Carex nebrascensis Nebraska sedge native OBL IF VC F Carex pellita syn. C. lanuginosa woolly sedge native OBL F Carex praegracilis clustered field sedge native FACW F F Carex vesicaria blister sedge native OBL IF Catabrosa aquatica water whorlgrass native OBL IF Dactylis glomerata orchard grass exotic FACU IF VC F Eleocharis palustris common spikerush native OBL F Equisetum arvense field horsetail native FAC F F IF F F Equisetum hyemale tall scouring rush native FACW IF IF Glyceria grandis American mannagrass native OBL IF Hordeum brachyantherum meadow barley native FACW F
B-11 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South Hordeum jubatum foxtail barley native FAC F IF IF Juncus balticus syn. J. arcticus Baltic or Arctic rush native FACW F F F Juncus compressus roundfruit rush exotic OBL IF F F Juncus ensifolius swordleaf or dagger‐leaf rush native FACW IF Juncus interior inland rush native FAC F Juncus longistylis long‐style rush native FACW IF Juncus nodosus knotted rush native OBL IF Pharlaris arundinacea reed canarygrass native FACW IF F F IF VC VC Phleum pratense common timothy exotic FAC VC F F F F Poa pratensis Kentucky bluegrass exotic FAC VC F F F Scirpus mircrocarpus small‐fruited, red‐tinge, or panicled bulrush native OBL F Typha latifolia broad‐leaf cat‐tail native OBL VC
B-12 Species Common Name NativityWetland Indicator* Upland Herbaceous Upland herbaceous Homestead Riparian Riparian Riparian Wetland Wetland Aspen Forest Notes Parcel South Triangle South South North Triangle South Triangle South VINE Clematis ligusticifolia western white clematis native FAC F Polygonum convolvulus black bindweed exotic ‐‐‐ F *Wetland Indicator: Lichvar, R. 2012. The National Wetland Plant List. ERDC/CRREL TR‐12‐11. U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire. Obtained at <http://rsgisias.crrel.usace.army.mil/NWPL>. Occurrence: VC = Very Common occurrence F = Frequent occurrence IF = Infrequent occurrence Nomenclature follows: Lesica, P. 2012. Manual of Montana Vascular Plants. Brit Press, Fort Worth, Texas. No rare plants observed.
C-1
APPENDIX C
ASSUMPTIONS USED IN THE DEVELOPMENT OF
THE CONCEPTUAL ALTERNATIVES
C-2
APPENDIX C
ASSUMPTIONS USED IN THE DEVELOPMENT OF
THE CONCEPTUAL ALTERNATIVES
GLOBAL ASSUMPTIONS
1. Unit costs were developed from a variety of standard cost estimating sources including:
RSMeans Cost Data (national cost database), Montana Department of Transportation
(MDT) unit prices, specific quotes from local and regional suppliers/vendors, and cost
information from other similar projects maintained by local RESPEC staff.
2. Project implementation would incorporate standard contracting format and would be
conducted during a favorable construction window.
3. The following buffer distances would be maintained for buried utility lines (i.e., gas,
sewer, and water):
Utility Horizontal Buffer Vertical Buffer
Natural Gas 20 feet from line No disturbance of existing ground
surface (NOTE: This was changed to 25’ from line
for the Selected Alternative).
Sanitary Sewer 5 feet from line Maintain minimum 5 feet of cover
Water 5 feet from line Maintain minimum 6.5 feet of cover
4. Overhead electric power poles would maintain the existing ground elevation at their
base and extend a minimum of 5 feet in any direction from the base. Any grading
outside of this circle would only occur at a 5H:1V slope or less.
5. Building/structure removal would include all aboveground portions of the structures as
well as foundations, slabs-on-grade, and bridge abutments. No asbestos or lead paint is
present in the buildings.
6. Excavated material generated from on-site grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
Excess, excavated soil material would be disposed of on-site, primarily within the North
property.
7. No hazardous materials occur onsite.
C-3
Alternative 1—Ecological Restoration I
North Parcel Assumptions
1. Excavated material generated from floodplain grading would be placed on site within
the lower (west) portion of the former Bridger View trailer park. No grading of this
placed material is assumed.
2. The extent of debris removal (asphalt and concrete pieces) along the right (northern)
streambank is limited to 35 percent of the existing bank length proposed for floodplain
re-grading. The removal of debris would extend 6 feet into the bank and have a vertical
height of 6 feet from bank toe to upper limits.
3. Existing mature trees (diameter at breast height (dbh) > 10 in.) along right bank would
be left in place (along with any debris material that is functioning to support the tree).
Gap areas between mature trees (identified on drawings) would be graded to facilitate
floodplain access.
4. Existing floodplain/wetland area on right bank would be used to control and filter right
overbank return flows to the main channel.
5. Dedicated pedestrian access to the East Gallatin River would occur at two locations
within the North Parcel.
South Parcel Assumptions
1. Excavated material generated from floodplain/wetland grading would be placed on site
within the North Parcel—lower (west) portion of the former Bridger View trailer park.
No grading of this placed material is assumed.
2. Excavated material generated from floodplain grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
3. The existing driveway into the South Parcel from Griffin Drive will be maintained up to
the point where it begins to curve to the east.
4. Existing large trees within the farmstead area would be retained.
5. The existing pond will be filled and re-graded; existing berms along both sides of the
pond would be re-graded and used for fill material and planted with riparian vegetation.
6. There will be no dedicated pedestrian access to the East Gallatin River or Bozeman
Creek from within the South Parcel.
7. Clean-up of debris along the river corridor will only occur along the left streambank
(East Gallatin River).
8. Existing gravel base material surrounding the farmstead buildings and extending up the
driveway to where it would be terminated from Griffin Drive would be removed to a
depth of 1 foot, and the resulting area would be revegetated with upland vegetation.
C-4
9. The water-quality floodplain slough/swale feature included for Bozeman Creek is based
on the following assumptions:
- Excavation of swale will not extend deeper than the adjacent Bozeman Creek channel
invert. This would minimize the potential for the slough feature to act as a drain to
the adjacent Bozeman Creek channel.
- A maximum of 2 percent of the total flow in Bozeman Creek would flow into the
floodplain swale at the 2-year flood event.
- The outfall of the slough back into Bozeman Creek would be adequately protected
with vegetation and/or geotextiles to prevent erosion and headcutting up the slough.
Triangle Parcel Assumptions
1. Excavated material generated from floodplain grading would be placed on-site within
the North Parcel—lower (west) portion of the former Bridger View trailer park. No
grading of this placed material is assumed.
2. Excavated material generated from floodplain grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
3. Dedicated pedestrian access to the East Gallatin River will occur at a single location
within the Triangle Parcel.
4. The existing car garage, bridge, and slaughterhouse buildings would be removed.
5. The driveway into the parcel from Story Mill Road would be truncated at the existing
house (green roof).
Alternative 2—Ecological Restoration II
North Parcel Assumptions
Excavated material generated from floodplain grading would be placed on site within the
lower (west) portion of the former Bridger View trailer park. No grading of this placed
material is assumed.
The extent of debris removal (asphalt and concrete pieces) along the right (northern)
streambank is limited to 35 percent of the existing bank length proposed for floodplain
re-grading. Removal of debris would extend 6 feet into the bank and have a vertical
height of 6 feet’ from bank toe to upper limits.
Existing mature trees (dbh > 10 inches) along right bank would be left in place (along
with any debris material that is functioning to support the tree). Gap areas between
mature trees (identified on drawings) would be graded to facilitate floodplain access.
Existing floodplain/wetland area on the right bank would be used to control and filter
right overbank return flows to the main channel.
C-5
Dedicated pedestrian access to the East Gallatin River will occur at two locations within
the North Parcel.
South Parcel Assumptions
1. Excavated material generated from floodplain/wetland grading would be placed on site
within the North Parcel—lower (west) portion of the former Bridger View trailer park.
No grading of this placed material is assumed.
2. Excavated material generated from floodplain grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
3. The existing driveway into the South Parcel from Griffin Drive will be maintained up to
the point where it begins to curve to the east.
4. Existing large trees within the farmstead area would be retained.
5. The existing pond will be filled and re-graded; the existing berm along the west side of
the pond would be re-graded and used for fill material, and the existing berm along the
east side of the pond would not be re-graded and would be planted with riparian
vegetation.
6. There will be no dedicated pedestrian access to the East Gallatin River from within the
South Parcel.
7. No clean-up of debris along the river corridor (East Gallatin River) would occur.
8. The area surrounding the farmstead buildings would be planted with upland seeding.
Triangle Parcel Assumptions
1. Excavated material generated from floodplain grading would be placed on site within
the North Parcel—lower (west) portion of the former Bridger View trailer park. No
grading of this placed material is assumed.
2. Excavated material generated from floodplain grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
3. Dedicated pedestrian access to the East Gallatin River will occur at a single location
within the Triangle Parcel.
4. The existing car garage would be removed.
5. The driveway into the parcel from Story Mill Road would be truncated at the existing
house (green roof).
C-6
Alternative 3—Passive Restoration
North Parcel Assumptions
1. Dedicated pedestrian access to the East Gallatin River would occur at two locations
within the North Parcel.
South Parcel Assumptions
1. Excavated material generated from re-grading would be placed on-site within the North
Parcel—lower (west) portion of the former Bridger View trailer park. No grading of this
placed material is assumed.
2. The existing driveway into the South Parcel from Griffin Drive will be maintained up to
the point where it begins to curve to the east.
3. There will be no dedicated pedestrian access to the East Gallatin River from within the
South Parcel.
4. Existing large trees within the farmstead area would be retained.
5. No clean-up of debris along the river corridor (East Gallatin River) would occur.
6. Existing gravel base material surrounding the farmstead buildings and extending up the
driveway to where it would be terminated from Griffin Drive would be removed to a
depth of 1 foot and the resulting area would be revegetated with upland vegetation.
Triangle Parcel Assumptions
1. Excavated material generated from floodplain grading would be placed on site within
the North Parcel—lower (west) portion of the former Bridger View trailer park. No
grading of this placed material is assumed.
2. Excavated material generated from floodplain grading consists of existing surface
vegetation and clean soil. Material does not contain large debris or hazardous materials.
3. Dedicated pedestrian access to the East Gallatin River would occur at a single location
within the Triangle Parcel.
4. The existing car garage would be removed.
D-1
APPENDIX D
CONCEPTUAL RESTORATION DESIGN ALTERNATIVE FIGURES
D-2
Table D-1. Story Mill Conceptual Design Legend Supplement (September 12, 2013)
Legend Item Description
Overhead electric
Overhead electric powerline. A 5-foot buffer around the pole was used as a no
disturb zone. From that point outward, a 5:1 slope was used to bring that elevation
down to surround the new floodplain elevation. Altogether, this resulted in a 25–
foot buffer area around the power poles.
Gas (40-foot buffer) Natural gas pipeline. A 20-foot buffer was applied to either side of this pipeline to
ensure no impacts would occur.
Sanitary sewer (10-foot
buffer)
Sanitary sewer pipeline. A 5-foot buffer was applied to either side of this pipeline to
ensure no impacts would occur.
Water (10-foot buffer) Water pipeline. A 5-foot buffer was applied to either side of this pipeline to ensure
no impacts would occur.
Approximate property line Approximate property line of the parcels owned by The Trust for Public Land.
Existing wetland Wetland polygons were delineated by River Design Group Inc. in 2012.
Conceptual Trail
The conceptual trail feature has two components, a wetland observation trail and a
connector trail. Both are at grade in upland and riparian areas and on 4-foot-wide,
pressed wood boardwalk where it crosses wetlands. For costing purposes it is
assumed that the boardwalk would be built by the Montana Conservation Corps or
by volunteers.
Conceptual wetland
The area predicted to meet the jurisdictional requirements of a wetland following
restoration actions. The polygons indicated as willow cuttings are also expected to
meet the jurisdictional definition of a wetland.
Conceptual floodplain
The area that would be excavated to recreate floodplain areas. The willow cutting
polygons within these new floodplains represent the predicted extent of flooding
during the 2-year flood event. The surface of the floodplain and perimeter will be
made to be more natural in the final design (if selected). For conceptual design and
costing purposes we assumed a 1% continuous gradient along the floor of the
floodplain polygon from the edge of the stream to the outer extent of the polygons.
Conceptual ditch grading
These polygons represent the areas that would be filled and re-graded to raise
groundwater elevations. These newly re-graded areas would be seeded with a native
wetland seed mix.
Building/Structure
removal
Buildings and their foundations would be completely removed. The bridge on the
Triangle Parcel is included in this category.
Willow cuttings Areas that would be planted with willow cuttings are expected to meet jurisdictional
wetland requirements over time. Cuttings would be planted in patches.
Riparian vegetation
Areas that would be drill seeded with a native riparian seed mix. Containerized
plantings are not currently proposed because of the need to provide irrigation for one
or two years following installation. However, we do have a list of proposed plantings
if these are desired.
Upland vegetation
Areas would be drill seeded with a native upland seed mix. Containerized plantings
are not currently proposed because of the need to provide irrigation for 1 or 2 years
after installation. However, we do have a list of proposed plantings if these are
desired. For the upland seeding areas on the Triangle Parcel (particularly
Alternatives 2 and 3), excavating the gravel parking lots to a depth of 1 foot, and
replacing 1foot of topsoil prior to seeding with native upland species are envisioned.
Natural revegetation Areas that are currently revegetating and do not require active restoration efforts.
D-3
D-4
D-5
D-6
D-7
D-8
D-9
D-10
D-11
D-12
D-13
D-14
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E-1
APPENDIX E
CONCEPTUAL RESTORATION DESIGN SELECTED ALTERNATIVE
FIGURES
E-2
Table E-1. Story Mill Conceptual Design Legend Supplement (Note that several elements
in the legend have been revised from the original legend to improve understanding of the figures)
Legend Item Description
Overhead electric
Overhead electric power line. A 5-foot buffer around the pole was used as a no
disturb zone. From that point outward, a 5:1 slope was used to bring that elevation
down to surround the pole at the new floodplain elevation. Altogether, this resulted
in a 25–foot buffer area around the power poles.
Gas (50-foot buffer) Natural gas pipeline. A 25-foot buffer was applied to either side of this pipeline to
ensure no impacts would occur.
Sanitary sewer (10-foot
buffer)
Sanitary sewer pipeline. A 5-foot buffer was applied to either side of this pipeline to
ensure no impacts would occur.
Water (10-foot buffer) Water pipeline. A 5-foot buffer was applied to either side of this pipeline to ensure
no impacts would occur.
Approximate property line Approximate property line of the parcels owned by The Trust for Public Land.
Existing wetland Wetland polygons were delineated by River Design Group Inc. in 2012.
Conceptual Trail
The conceptual trail feature has two components, a wetland observation trail and a
connector trail. Both are at grade in upland and riparian areas and on 4-foot-wide,
pressed wood boardwalk where it crosses wetlands. For costing purposes it is
assumed that the boardwalk would be built by the Montana Conservation Corps or
by volunteers.
Restored wetland
(formerly Conceptual
wetland)
The area predicted to meet the jurisdictional requirements of a wetland following
restoration actions. The polygons indicated as willow cuttings are also expected to
meet the jurisdictional definition of a wetland.
Restored Floodplain
(formerly ‘Conceptual
floodplain’)
The area that would be excavated to recreate floodplain areas. The willow cutting
polygons within these new floodplains represent the predicted extent of flooding
during the 2-year flood event. The surface of the floodplain and perimeter will be
made to be more natural in the final design (if selected). For conceptual design and
costing purposes we assumed a 1% continuous gradient along the floor of the floodplain polygon from the edge of the stream to the outer extent of the polygons.
Restored wetland
(Grading)
(formerly ‘Conceptual ditch
grading’)
These polygons represent the areas that would be filled and re-graded to raise
groundwater elevations. These newly re-graded areas would be seeded with a native
wetland seed mix.
Building/Structure
removal Buildings and their foundations would be completely removed.
Willow cuttings (Wetland)
(formerly ‘Willow cuttings’)
Areas that would be planted with willow cuttings are expected to meet jurisdictional
wetland requirements over time. Cuttings would be planted in patches.
Riparian vegetation
Areas that would be drill seeded with a native riparian seed mix. Containerized
plantings are not currently proposed because of the need to provide irrigation for one
or two years following installation.
Upland vegetation
Areas would be drill seeded with a native upland seed mix. Containerized plantings
are not currently proposed because of the need to provide irrigation for 1 or 2 years
after installation. For the upland seeding areas on the Triangle Parcel, excavating
the gravel parking lots to a depth of 1 foot, and replacing 1-foot of topsoil prior to
seeding with native upland species are envisioned.
Natural revegetation Areas that are currently revegetating and do not require active restoration efforts.
Naturalized pond The existing pond would be reconfigured and planted with willows. Configuration is
based on the original design by River Design Group.
E-3
E-4
E-5
E-6