Amend_0001_Atch_2_Redacted_Bone_Hill_Dam_Removal_0001.pdf

Bone Hill Dam Removal Design Report January 22, 2021

Page ii

BONE HILL NATIONAL WILDLIFE REFUGE

BONE HILL DAM REMOVAL

DESIGN SUMMARY REPORT

DESIGN SUBMITTAL

TABLE OF CONTENTS

TABLE OF CONTENTS ................................................................................................. ii

LIST OF TABLES ..........................................................................................................iii

LIST OF FIGURES .........................................................................................................iii

LIST OF APPENDICES .................................................................................................iii

1.0 BACKGROUND

2.0 PROJECT FEATURES

3.0 DATA COLLECTION

3.1 Geotechnical and Subsurface Evaluations

3.2 Survey

4.0 HYDRAULIC DESIGN

4.1 Inflow Hydrology

4.1.1 Drainage Basin Characteristics

4.1.2 Basin Soils and Infiltration

4.1.3 Precipitation

4.1.4 Unit Hydrograph

4.1.5 Reservoir Capacity Curve

4.1.6 Inflow Hydrology Summary

4.2 Reservoir Routing and Breach Sizing Analysis

4.3 Downstream Inundation Evaluation

4.4 Sedimentation Analysis

5.0 OTHER DESIGN CONSIDERATIONS

5.1 Permitting

5.2 Remove Existing Combined Service Spillway and Outlet Works

5.2 Riprap Sizing

5.3 Low Flow Concrete Structure

5.4 Soil Bearing and Settlement

6.0 CONSTRUCTION CONSIDERATIONS

6.1 Reservoir Control

6.2 Site Dewatering

6.3 Demolition and disposal

Page iii

6.4 Opinion of Construction Cost

7.0 REFERENCES

LIST OF TABLES

Table 1 Summary of Key Drainage Basin Parameters

Table 2 Summary of Soil and Infiltration Parameters

Table 3 100-Year Point Rainfall Depths

Table 4 Summary of Unit Hydrograph Characteristics

Table 5 Summary of Inflow Hydrology

Table 6 Summary of Reservoir Routing

Table 7 Construction Cost Opinion Bid Tab

LIST OF FIGURES

Figure 1 Basin Characteristics

Figure 2 Soil Map

Figure 3 Inundation Limits

LIST OF APPENDICES

Appendix A Design Drawings

Appendix B Specifications

Appendix C Geotechnical Investigation Report

Appendix D HEC-HMS Inputs and Results

D.1 – Basin Soils and Infiltration Rates

D.2 – Precipitation

D.3 – Unit Hydrograph Development

D.4 – Reservoir Capacity Curves

D.5 – Existing Spillway Curves

D.6 – Breach Opening Curve and Results

Appendix E Field Photos

Appendix F Environmental Review

Appendix G Riprap Sizing Calculation

Appendix H Soil Bearing and Settlement Calculation

Appendix I Construction Cost Opinion

\\Ww-Rs1\CLIENT\1700\1772\1772.38_Bonehill_Removal\7_Documents\100_Pct\Bonehilldesignreport_100pct_Jan2020.Docx

1.0 BACKGROUND

Bone Hill Dam was originally designed and constructed by the U.S. Department of

Agriculture, Biological Survey (currently U.S. Fish and Wildlife Services). The dam is owned and operated by the U.S. Fish and Wildlife Service (FWS). The dam is located in the southern part of North Dakota FWS Region 6 northeast of Jud, ND. The general vicinity of the site is shown on the Project Drawings.

The dam is a low hazard-potential earthen embankment located on a small tributary of

Bone Hill Creek that flows into the James River. The stored water is primarily used as habitat and breeding areas for migratory birds and other wildlife as part of the Bone Hill

Creek National Wildlife Refuge (NWR), which is an easement Refuge established by

Executive Order Number 8112 dated May 10, 1939. The dam has a structural height of approximately 14.3 feet and a crest length of approximately 1,750 feet with an active storage of approximately 77.5 acre-feet. At the reservoir’s normal high-water line, the reservoir has a surface area of about 11 acres.

Major repairs and improvements to Bone Hill Dam were completed in 1994 and included enlarging the reservoir pool, widening the dam crest, and installing a combined service spillway and low-level outlet works. The updated design also included a clay core and downstream toe drain system. Shortly after construction, the dam breached due to piping along the CMP pipe because of poor compaction of the embankment material around the

CMP. The structure was again reconstructed with a clay core keyed into the foundation and extended the length of the embankment.

An Intermediate SEED Inspection was completed on August 12, 2010 by URS. The dam was given an overall safety classification as “POOR” due to the erosion of the dam crest, severe headcutting of the auxiliary spillway, and backcutting of the upstream embankment around the outlet works conduit and headwall. Immediate actions to resolve these deficiencies were recommended.

Due to recent wet seasons and significant flooding in the James River basin, Bone Hill

Dam has experienced overtopping and erosion. Based on our initial site assessment completed on July 15, 2020, several dam safety issues were identified:

1. Inadequate spillway capacity;

2. Erosion of the auxiliary spillway channel;

3. Evidence of significant corrosion of the CMP outlet works conduit;

4. Evidence of significant piping and undermining around the outlet works conduit;

5. Evidence of significant erosion of the upstream embankment around the combined service spillway and outlet works; and

6. Inoperable service spillway due to bent stoplog channels.

In addition to the dam safety concerns, the property owner and FWS Refuge Manager both expressed concerns related to the downstream auxiliary spillway erosion creating a hazardous area for the cattle that graze on the property.

Due to the current condition of the dam, the FWS Region 6 Division of Engineering Office has decided to decommission the dam and construct a permanent breach within the embankment. W.W. Wheeler & Associates (Wheeler) was contracted to complete the preliminary design and engineering required by FWS to decommission the dam (FWS, 2015). This report documents the design criteria, assumptions, and calculations used to decommission the FWS Dam.

2.0 PROJECT FEATURES

The decommissioning of Bone Hill Dam will remove the dam from the FWS dam inventory, discontinue the water easement right to the dam, and abandon the existing water right.

The key project features of the removal of the dam include:

1. Excavate a trapezoidal breach along the existing dam embankment to have a bottom with of 50-feet, side slopes of 5 Horizontal (H) : 1 Vertical (V).

2. Remove the existing combined service spillway and outlet works structure.

3. The downstream breach opening and discharge channel will have a longitudinal slope of approximately 1-percent.

4. The upstream breach section will be sloped at a 3H: 1V.

5. A concrete low-water crossing will be installed in the breach to allow the property owner access across the breached section.

6. Armor the downstream breach opening with median rock size (D50) of 1-foot to protect the embankment from long-term erosion and head cutting of the embankment soils.

7. Place the excavated embankment fill into the auxiliary spillway to flatten the steep slopes and eliminate the hazard for the cattle.

8. Place the excavated embankment fill to backfill the foundation of the proposed breach where the outlet works CMP was removed.

3.0 DATA COLLECTION

3.1 GEOTECHNICAL AND SUBSURFACE EVALUATIONS

Four test borings 20 feet deep were located along the existing dam embankment near the low-level outlet works. The borings were performed by Terracon Consultants (Terracon) in July 2020 as part of a subsurface exploration and laboratory testing program. The location of the borings and a summary of the testing results are provided in Appendix C.

The embankment material identified in the borings generally consists of a clayey sand

(SC) and sandy clay (CL). A buried layer of topsoil was observed in the first two borings which probably represents the old dam crest prior to the enlargement in 1994. The material observed in general has the following characteristics:

Description Clayey Sand (SC) and Lean Clay (CL) Liquid Limit 38 – 40% Plastic Limit 17% Plasticity Index 21 – 23%

% Passing -200 Sieve 15 - 62%

3.2 SURVEY

Topographic data of the project site and downstream hazards was obtained from two different sources:

• Holly Beck Surveying & Engineering completed a land survey of the dam crest

(Holly Beck, 2020), combined service spillway and outlet works inverts and dimensions, cross-sections of the auxiliary spillway extending from the dam crest to the downstream culvert at 75th Avenue and the invert and dimensions of the culvert at 75th Avenue. The survey data was provided in North Dakota State

Plane North American Datum of 83 (NAD83) Coordinates using North American

Vertical Datum of 88 (NAVD88).

• 1.4-meter Statewide LiDAR derived elevation data obtained from the North

Dakota GIS Hub acquired by USACE St. Louis District (USACE, 2010). The

LiDAR elevation uses NAVD88 and was flown in 2010.

4.0 HYDRAULIC DESIGN

4.1 INFLOW HYDROLOGY

A comprehensive hydrologic rainfall-runoff computer simulation model of the contributing basin to Bone Hill Dam was developed with U.S. Army Corps of Engineers (USACE)

Hydrologic Modeling System (HEC-HMS) Version 4.2.1 software (USACE, 2017) to estimate runoff from a 100-year recurrence interval precipitation event during a 24-hour duration storm occurring over the basin. Discharges from the Bone Hill Dam basin were routed through the existing Bone Hill Reservoir and designed breach. Pertinent HEC HMS input and output data is provided in Appendix D. Key steps in the development of this inflow included:

1. Determine drainage characteristics for the basin;

2. Develop the 100-year recurrence interval precipitation data, including the depth vs. duration relationship and temporal distribution;

3. Create a reservoir capacity curve; and

4. Develop a synthetic unit hydrograph to simulate the transformation of rainfall to runoff in the drainage basin.

4.1.1 Drainage Basin Characteristics

The boundary for the drainage basin contributing runoff to Bone Hill Dam was developed using the North Dakota Statewide LiDAR data (USACE, 2010). Figure

No. 1 shows the basin and basin parameters used to model the hydrologic response. Table No. 1 summarizes the key drainage basin parameters including area, calculated longest flow path, longest flow path from centroid, change in elevation from the basin maximum elevation to sub-basin minimum elevation and average basin slope that was calculated in ArcGIS (ESRI, 2018).

Table No. 1 – Summary of Key Drainage Basin Parameters

Dam Name Bone Hill Dam

Drainage Area (sq. miles) 7.02

Longest Flowpath, L (miles) 5.634

Longest Flowpath to Centroid, Lca (miles) 2.880

Slope of Longest Flowpath, S (feet / mile) 32.83

Basin Maximum Elevation, (feet) 1841

Sub-Basin Minimum Elevation, (feet) 1639

4.1.2 Basin Soils and Infiltration

The soil characteristics for the basin were obtained from the United States

Department Agriculture (USDA) National Resources Conservation Service

(NRCS). The NRCS soils data indicated that on-site soils consist of a mixture of sands, silts and clays (NRCS, 2020). The NRCS soils data also indicated the dominant hydrologic soil group for each soil type identified. Within the basin, soil types B, C and D were present. These soil groupings were used to determine recommended infiltration rate for each soil type following U.S. Bureau of

Reclamation guidelines (USBR, 1989). Once infiltration rates were determined, a weighted average infiltration rate was calculated for the basin. The average infiltration rate and percent imperviousness of the basin are summarized in Table

No. 2. A soil map for the basin is provided on Figure 2, and infiltration calculations are provided in Appendix D1.

Table No. 2 – Summary of Soil and Infiltration Parameters

Weighted Average Infiltration (inch/hour) 0.21

Percent Impervious (%) 0.80

4.1.3 Precipitation

The 100-year, 24-hour precipitation for the basin was estimated following procedures documented in National Oceanic and Atmospheric Administration

(NOAA) Atlas 14, Volume 8, Version 2.0 (DOC, 2013). The 100-year, 24-hour precipitation depth versus duration values for Bone Hill basin are provided in Table

No. 3. Detailed calculations for the areal reduction and temporal distribution of the

100-year precipitation depth-duration values are documented in Appendix D2.

Table No. 3 – 100-Year Point Rainfall Depths

5-min 15-min 1-Hr 2-Hr 3-Hr 6-Hr 12-Hr 24-Hr

(inches) (inches) (inches) (inches) (inches) (inches) (inches) (inches)

0.997 1.78 3.12 3.79 4.16 4.74 5.24 5.67 Runoff model used 100-yr rainfall applied using 1st Quartile, 50% Probability of Occurrence temporal distribution.

4.1.4 Unit Hydrograph

The unit hydrograph was developed for the basin using the dimensionless unit hydrograph technique as documented in Chapter 4 of the USBR Flood Hydrology

Manual (USBR, 1989). Detailed unit hydrograph calculations are provided in

Appendix D3. The USBR unit hydrograph procedure is based on the observation that unit hydrograph lag time is a function of measurable basin parameters. For the dimensionless unit hydrograph, the lag time is defined as the time from the center of unit rainfall excess to the time at which 50 percent of the runoff has passed the concentration point. The following equation was used to determine the lag time for each basin:

Lg= Ct (L Lca / S0.5)0.33 where:

Lg = Lag time (hours);

Ct = a constant equal to (26 * Kn);

L = length of the longest watercourse (miles);

Lca = length along the longest watercourse from the point of interest to a point opposite the centroid of the basin, (miles); and

S = overall slope of the longest watercourse from the point of concentration to the drainage basin divide, (feet / mile).

Ct values are approximated as 26 times Kn, where Kn is estimated as the average

Manning’s roughness value for the principal watercourse in the drainage basin.

The Kn value was selected based on review of similar drainage basins in the region as documented in Table No. 4.3 of the USBR Flood Hydrology Manual (USBR, 1989). Kn values for the Great Plains area (Type 4) range between 0.03 and

0.076; the value selected, 0.036, was considered appropriate for the development of reasonable lag times in the basin. Kn along with associated Ct and lag time (Lg) values used for the basin are summarized in Table No. 5.

Table No. 4 – Summary of Unit Hydrograph Characteristics

Kn 0.036

Ct 0.936

Lag Time, Lg (hours) 1.3

4.1.5 Reservoir Capacity Curve

Documentation of the development of the reservoir storage versus capacity relationship used in the HEC-HMS hydrologic reservoir routing model is provided in Appendix D4. The reservoir capacity was calculated based on the best available topographic information including the LiDAR data and survey data.

4.1.6 Inflow Hydrology Summary

Wheeler used the HEC-HMS model to simulate the runoff associated with the 100-year precipitation event and route the inflow through Bone Hill Dam and breach to determine if the proposed breach dimensions met the criteria for decommissioning low hazard FWS dams. The HEC HMS model was developed using the basin, reservoir and rainfall characteristics described in Sections 4.1.1 through 4.1.5.

Peak runoff results of the 100-year storm from the HEC-HMS model are summarized in Table No. 6.

Table No. 5 – Summary of Inflow Hydrology

Parameter 100-year, 24-hour Frequency Storm

Peak Inflow (cfs) 2,763

Inflow Volume (acre-feet) 1,173

4.2 RESERVOIR ROUTING AND BREACH SIZING ANALYSIS

The HEC-HMS model and inflows described in Section 4.0 were used to design the proposed breach dimensions at Bone Hill Dam. The breach dimensions were evaluated in accordance with FWS’s guidance for decommissioning low hazard dams (FWS, 2015).

According to the FWS guidance, the size of the breach should be sufficient to pass the

100-year flood peak discharge (assuming no initial reservoir storage) with a maximum reservoir depth of six feet and the breach width should not be less than the bottom width of the original natural channel at the dam site.

Observations made during the 2020 site visit indicated a smaller meandering low-flow channel downstream of the existing low-level outlet works. The elevation at the downstream toe of the dam is approximately 5-feet higher than the invert of the outlet works and has a longitudinal slope of approximately 1-percent. A large group of woody vegetation is located approximately 10 feet downstream of the outlet works where the low-flow channel meanders to the right around the vegetation before it continues downstream.

Pictures of the downstream channel, dam embankment and downstream toe are provided in Appendix E.

Aerial imagery, survey elevations and LiDAR data were used to estimate the natural channel width and slope. The downstream natural ground is both wide and flat, forming a slough feature that drains water from the reservoir into a downstream network of braided channels. The design drawings provided in Appendix A provides an illustration of the existing dam and proposed breach location, a profile and a cross-section of the breach.

Three scenarios were developed to route the 100-year storm as described below:

1. Basin Model ‘100yr’ = Estimated the 100-year inflow design storm only (no reservoir routing).

2. Basin Model ‘100yr w Res’ = Estimated the 100-year inflow design storm with existing reservoir routing. Assumed an initial reservoir elevation as the maximum normal pool El. 1639 as documented in the Pertinent Data and modeled two spillway curves as documented in Appendix D5.

3. Basin Model ‘100yr Breach’ = Estimated the 100-year inflow design storm with the breached reservoir routing. Assumed an initial reservoir elevation as the proposed breach invert El at 1635.15 and a breach opening curve documented in

Appendix D6.

The 100-year reservoir routing results through Bone Hill Lake are summarized in Table 6.

The proposed 50-foot breach resulted in a depth of 4.95 feet, which is less than 6 feet;

therefore, this breach was used for the final design.

Table No. 6 – Summary of Reservoir Routing

Parameter Existing

Basin Model ‘100yr w Res’

Proposed Basin Model

‘100yr Breach’

Peak Discharge (cfs) 2,762 2,754

Maximum Water Surface Elevation

1642.5 1640.1

Reservoir Depth above proposed breach invert of 1635.15 (ft)

7.35 4.95

4.3 DOWNSTREAM INUNDATION EVALUATION

As part of the FWS decommissioning guidance, Wheeler developed a downstream inundation model of Bone Hill Lake to demonstrate that no downstream structures are adversely impacted during the 100-year inflow design flood of Bone Hill Dam. To assess the downstream structures, Wheeler developed a two-dimensional (2D) HEC-RAS unsteady flow model for channel and overland routing downstream of Bone Hill Dam. The model was setup with 50- by 50-foot grids that extend from Bone Hill Dam to downstream of Nortonville, ND. The 2D grids extract elevations from a 1-meter digital elevation model that was derived from LiDAR data and survey data described in Section 3. Three different scenarios were modeled as described below:

1. Existing Conditions – routing the 100-year design storm through the existing dam features;

2. Existing Conditions pre dam – routing the 100-year design storm as if no dam existed at that location; and

3. Proposed Conditions – routing the 100-year design storm through the proposed breach.

Two modified terrains were developed for the project using features available through

HEC-RAS. The first terrain was modified to match the proposed breach and this terrain was used for the Proposed Conditions model. The second terrain was modified to interpolate the terrain between the natural ground upstream of the dam and downstream of the dam to simulate natural conditions without the dam. This terrain was used for the existing conditions pre-dam model. The original terrain developed from the LiDAR data was used for the Existing Conditions model.

Inflow hydrographs for the three scenarios were optioned from the HEC-HMS model described in Section 4.1 and 4.2. The model was terminated downstream of the Town of

Nortonville because no more structures were identified as potentially impacted. The

“Diffusion Wave” set of simplified Saint Venant equations were used to run the 2D water surface profile model with a computational timestep of five seconds. These equations were judged appropriate because no dramatic increases and decreases in the flow hydrographs are expected and the terrain is flat.

Two-dimensional surface roughness was added to the 2D HEC-RAS model based on manning’s roughness of the National Land Cover Database (USGS, 2016). The manning’s values applied to the land use were obtained from Colorado Rules and Regulations (DWR, 2020). The following 2D roughness values were incorporated in the model as follows:

• Main channel, vegetation – 0.05

• Emergent wetlands – 0.075

• Woody wetlands – 0.095

• Cultivated crops – 0.047

• Pasture – 0.04

• Grasslands – 0.037

• Shrubs – 0.082

• Deciduous forest – 0.115

• Developed area, high intensity – 0.147

• Developed area, medium intensity – 0.104

• Developed area, low intensity – 0.095

• Developed – 0.046

• Open water – 0.032

A bridge structure was added to the 2D flow area at the closest downstream crossing, 75th

Avenue Southeast. A breakline was added along the center of the road for the other crossings as a conservative approach; however, this did not result in any of the structures within the Town being adversely impacted by the proposed breach during the 100-year design storm. The culvert dimensions were measured by Wheeler with a hand-level and tape during the July 2020 site visit to Bone Hill Dam. The results of the downstream inundation evaluation for the three different scenarios are shown on Figure No. 3. Based on the inundation limits, no adverse impacts are expected at Bone Hill Dam after the dam is decommissioned.

4.4 SEDIMENTATION ANALYSIS

The breach of Bone Hill Dam has been designed with a small permanent dead reservoir pool that will simultaneously act as a sedimentation trap. This sedimentation trap is designed to reduce sedimentation moving downstream during smaller, more frequent storms. The approximate 3-foot-deep reservoir pool was included in the design to maintain a historical water source for the landowner’s cattle as well as function as a sediment basin.

5.0 OTHER DESIGN CONSIDERATIONS

5.1 PERMITTING

ERO resources completed an environmental review of the permitting requirements and process required for the removal of Bone Hill Dam. The complete report is provided in

Appendix F. Based on their assessment, Bone Hill Dam would need to be permitted under the following regulations:

• National Environmental Policy Act (NEPA);

• U.S. Army Corps of Engineers’ (USACE) Section 404 of the Clean Water Act

(CWA);

• U.S. Fish and Wildlife Service (USFWS) Section 7 of Endangered Species Act

(ESA) and Biological Assessment;

• State Historic Preservation Officer (SHPO); and

• Migratory Bird Treaty Act (MBTA).

USFWS and ERO are working together to determine the level and types of permits required for Bone Hill Dam. Preliminary determinations and conclusions regarding the permits listed above are summarized below:

1. NEPA – A categorical exclusion was selected because the anticipated environmental effects are not expected to be significant.

2. USACE 404 – A Nationwide 27 permit is required and has been obtained for this project.

3. USFWS Section 7 – Based on ERO site visit and USFWS Refuge Manager, the project would likely have no effect on any threatened or endangered species;

however, no official determination has been provided.

4. SHPO - USFWS Refuge Manager has started the process to obtain the SHPO permit required for the project.

5. MBTA – This permit is triggered if an active nest is present during construction, but this permit can be avoided if construction occurs outside of active breeding season between March and August.

5.2 REMOVE EXISTING COMBINED SERVICE SPILLWAY AND OUTLET WORKS

The removal of the existing combined service spillway and outlet works is shown on the design drawings provided in Appendix A. As discussed in Section 1, during the field visit in July 2020, significant piping and erosion was observed in the upstream and downstream embankment near the outlet works 36-inch CMP. Additionally, the CMP was completely corroded in several locations. Pictures of the erosion and corroded CMP are provided in

Appendix E. Wheeler designed the breach to encompass the existing combined service spillway and outlet works. Wheeler also designed for an additional 2-feet of excavation below the breach crest to remove any loose sand or gravel that was placed and contributed to the existing seepage.

5.2 RIPRAP SIZING

Two different types of armoring are used in the decommissioning design of Bone Hill

Dam. As noted in the field visit, existing gabion erosion nets were previously used in the auxiliary spillway to prevent channel erosion. The gabion rocks have an approximate D50 of about 6-inches. The current gabion baskets are no longer effective after several larger storm events have displaced them within the downstream auxiliary channel. Wheeler’s design will use these gabion rocks as additional erosion protection downstream of the breach. The gabion rocks will be spread along the downstream breach over some geotextile matting to prevent scour and backcutting during larger storm events. Riprap will be installed upstream and downstream of the low water crossing. Appendix G provides detailed riprap sizing calculations using depths and velocities obtained from the

HEC-RAS model described in Section 4.3. Based on those calculations, Wheeler designed a Grade I riprap with a D50 equals 12-inches.

5.3 LOW FLOW CONCRETE STRUCTURE

A concrete low-water crossing will be installed through the breach to allow for vehicle access across the property. Concrete designs conform to the applicable requirements of

ACI 318-11 and ACI 350. Key parameters used in the design are:

1. Design compressive strength of concrete: 3,500 psi @ 28 days

2. Design yield strength of reinforcing bars: 60,000 psi

3. Minimum concrete cover over reinforcing bars: 3 inches

4. Unit weight of soil: 130 pcf

5. Soil friction angle (Φ): 30°

6. Soil pressure coefficient (Ko, “at-rest” pressure): 0.50

7. Unit weight of water: 62.4 pcf

The reinforcing steel design for the low water crossing was based on providing minimum temperature and shrinkage reinforcing steel in the structures to minimize cracking.

5.4 SOIL BEARING AND SETTLEMENT

Wheeler analyzed the low water crossing structure for the bearing capacity and settlement using a recommended traffic surcharge of 250 pound per square feet (psf). The factor of safety against bearing capacity was calculated to be greater than 3. Total settlement was calculated to be less than 0.3 inches. Bearing capacity and settlement analyses for the planned low water crossing are provided in Appendix H. Based on these analyses the planned structure meets the bearing capacity and settlement requirements.

6.0 CONSTRUCTION CONSIDERATIONS

6.1 RESERVOIR CONTROL

The level of reservoir control for this project will be decided by the selected Contractor.

The dam is located on an off-line channel and due to the dam deficiencies, the dam can no longer store water. The water surface elevation at the time of construction is expected to be around El. 1633 or lower, similar to the elevation at the time of the July 2020 site visit. The timing of the construction is anticipated to be late fall after the rainy season and before winter. The contractor can choose to either submit a reservoir control plan or watch the daily weather and plan construction activities accordingly.

6.2 SITE DEWATERING

Bone Hill Dam is expected to be drained naturally prior to construction because of the current erosion issues along the outlet works, the dam can no longer hold water. However, localized groundwater conditions and natural springs could cause localized groundwater issues during construction. Groundwater during construction is expected to be controlled by isolated sumps and pumps.

6.3 DEMOLITION AND DISPOSAL

The existing CMP headwall and outlet conduit, as well as unsuitable embankment material will be excavated and disposed off-site. Suitable excavated material from the dam embankment will be placed in the auxiliary spillway erosion areas as shown on the drawings.

7.0 REFERENCES

1. American Concrete Institute (ACI, 2006) ACI 350-06, Code Requirements for

Environmental Engineering Concrete Structures, 2006.

2. American Society of Civil Engineers (ASCE, 2007) Minimum Design Loads for

Buildings and Other Structures, 2007.

3. Geographic Information System Company (ESRI, 2018) ArcGIS Desktop Version

10.7.

4. Holly Beck Surveying & Engineering (Holly Survey, 2020), Land Survey, July 2020.

5. Natural Resources Conservation Services (NRCS, 2020), Web Soil Survey LaMoure

County, North Dakota, July 7, 2020, website:

https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm

6. U.S. Army Corps of Engineers (USACE, 2017) HEC-HMS Hydrology Modeling

System Version 4.2.1, March 2017.

7. U.S. Army Corps of Engineers St. Louis District (USACE, 2010), 1.4-meter Statewide

LiDAR North Dakota GIS Hub, Flown 2010 and 2011, website: https://lidar.swc.nd.gov/

8. U.S. Fish and Wildlife Service, (FWS, 2015), Guidance for Decommissioning U.S. Fish and Wildlife Service Low Hazard Dams, October 2015.

9. U.S. Fish and Wildlife Service, (FWS, 2010), Intermediate SEED Inspection Report

Bone Hill Dam, Prepared by URS Group, Inc., January 28, 2011.

10. U.S. Geological Survey (USGS, 2020), StreamStats Version 4.4.0, website:

https://streamstats.usgs.gov/ss/

11. U.S. Geological Survey (USGS, 2016), National Land Cover Database 2016, website: https://www.usgs.gov/centers/eros/science/national-land-cover-database?qt-science_center_objects=0#qt-science_center_objects

12. U.S. Bureau of Reclamation (USBR, 1989) Flood Hydrology Manual, First Edition

1989, Prepared by Arthur Cudworth Jr.

13. Terracon Consultants (Terracon, 2020), Geotechnical Exploration Report, July 2020.

https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm https://lidar.swc.nd.gov/ https://streamstats.usgs.gov/ss/ https://www.usgs.gov/centers/eros/science/national-land-cover-database?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/centers/eros/science/national-land-cover-database?qt-science_center_objects=0#qt-science_center_objects

Centroid

Bone Hill Dam

Longest Flow Path / Longest Flow Path from Centroid

Watershed (7.02 sq miles)

0 4,000 8,000 Feet Job No. 1772.38

Bone Hill National Wildlife Refuge Bone Hill Dam Removal

Basin CharacteristicsSE

PT

EM

BE

R

20BONE HILL

NATIONAL

WILDLIFE

REFUGE

FIGURE 1

Bone Hill Dam

0 4,000 8,000 Feet

Soil Group B B/D C C/D D Water

Job No. 1772.38

Bone Hill National Wildlife Refuge Bone Hill Dam Removal

Soil MapSE

PT

EM

BE

R

20BONE HILL

NATIONAL

WILDLIFE

REFUGE

FIGURE 2

Bone Hill Dam th Av e S E

2nd St th

Av e S

E

60th St SE th

Av e S

E th

Av e S

E

58th St SE th

Av e S

E

60th St SE

6th Ave th

Av e S

E th

Av e S

E th

Av e S

E

59th St SE

76th Ave SE th

Av e S

E th

Av e S

E

58th St SE st

Av e S

E

57th St SE

0 2,400 4,800

Feet

FWS Boundary Inundation Limits w/Existing Dam Inundation Limits w/50ft Breach Inundation Limits w/o a Dam

Job No. 1772.38

Bone Hill National Wildlife Refuge Bone Hill Dam Removal

Inundation LimitsJA

NU

AR

Y 2

BONE HILL NATIONAL

WILDLIFE REFUGE

FIGURE 3

2nd St

3rd Av e

59th St SE

5th Av e79 th

Av e S

E th

Av e S

E

0 1,500 3,000Feet

Appendix A Design Drawings

© 2020 Microsoft Corporation © 2020 Maxar ©CNES (2020) Distribution Airbus DS

BONE HILL CREEK NATIONAL

WILDLIFE REFUGE

BONE HILL CREEK NATIONAL

WILDLIFE REFUGE

REFUGE BOUNDARY

BONE HILL DAM

BISMARK

EDGLEY

BONE HILL

CREEK LAKE

0 200 500 1000 1500 Scale in Feet

LOCATION MAP

STATE MAP

(N.T.S.)

FISH AND WILDLIFE SERVICE

UNITED STATES DEPARTMENT OF THE INTERIOR

REGION 6 ENGINEERING - DENVER, COLORADO

DESIGNED:

DATE:

DRAWN:

DRAWING NO. SHEET 1 OF

CHECKED:

VICINITY MAP

NO SCALE

APPROVAL SIGNATURES

ANY PRINT ACCOMPANYING THIS INVITATION TO BID MAY BE A REDUCED

REPRODUCTION OF THE WORKING DRAWINGS. IF LINE BELOW DOES NOT

MEASURE SIX INCHES IN LENGTH, THE INDICATED SCALES ARE TO BE

ADJUSTED ACCORDINGLY.

NOTE TO BIDDERS:

REGIONAL ENGINEER

ASS'T. REGIONAL DIR.

DATE

PROGRAM SUPERVISOR

FACILITIES

SAFETY/IND HYGIENIST

CULTURAL RESOURCES

DATE

DATE

DATE

DATE

DATE

BONE HILL CREEK

NATIONAL WILDLIFE REFUGE

LAMORE COUNTY NORTH DAKOTA

BONE HILL DAM REMOVAL

LOCATION MAPS AND

DRAWING INDEX

CBM SAA JJT

01/22/2021 5

BONE HILL CREEK

BONE HILL DAM REMOVAL

REFUGE BOUNDARY

R:

\1

0\

\1

2.

_B on eH ill_

Re m ov al

\9 _D ra w in gs

\C

AD

F ile s\

IF

C\ Sh ee tF ile s\

-0

-0

8-

3:

pm

S co tt X

RE

FS

: J

JT

_s ta m p

JJ

T_ sig

DRAWING INDEX

SHEET

NUMBER SHEET TITLE

1 LOCATION MAPS AND DRAWING INDEX

2 ABBREVIATIONS, LEGEND, AND SITE ACCESS

3 EXISTING PLAN AND SECTION

4 GENERAL PLAN OF MODIFICATIONS

5 BREACH PLAN, PROFILE, AND CROSS-SECTION

FARGO

JO

HN

JO

SEPH TREACY

III

CO

LO

RADO L CENSED

I

PROFESSIONAL ENGINE

ER

47781

2/8/2021

AutoCAD SHX Text

OR

AutoCAD SHX Text

RI

AutoCAD SHX Text

ME

AutoCAD SHX Text

RT

AutoCAD SHX Text

PA

AutoCAD SHX Text

DE

AutoCAD SHX Text F

AutoCAD SHX Text O

AutoCAD SHX Text

NT

AutoCAD SHX Text

TE

AutoCAD SHX Text

IN

AutoCAD SHX Text E

AutoCAD SHX Text

TH

AutoCAD SHX Text

FISH AND WILDLIFE

AutoCAD SHX Text

SERVICE

AutoCAD SHX Text U.S.

AutoCAD SHX Text

U.S. FISH & WILDLIFE SERVICE

AutoCAD SHX Text

SERVICE

AutoCAD SHX Text

FISH AND WILDLIFE

AutoCAD SHX Text

TH

AutoCAD SHX Text

ME

AutoCAD SHX Text

RT

AutoCAD SHX Text

PA

AutoCAD SHX Text

DE

AutoCAD SHX Text

NT

AutoCAD SHX Text F

AutoCAD SHX Text O

AutoCAD SHX Text

OR

AutoCAD SHX Text

RI

AutoCAD SHX Text

TE

AutoCAD SHX Text

IN

AutoCAD SHX Text E

AutoCAD SHX Text U.S.

-13+33

-13+00

-12+00

-1 1+

-1 0+

00-9+00

-8+00

-7+00

-6+ 00-5

+0 0-4

+0

-3+00

-2+00

-1+000+

1+00

2+00

3+00

4+00

5+00

0 100 200 400 600 Scale in Feet

BONE HILL DAM

BONE HILL

CREEK LAKE

ACCESS ROAD

59TH STREET SE

LOCKED GATE

LOCKED GATE

TH

A

VE

NU

E

SE

S2

A S2

INDICATES CROSS SECTION LOCATION. "A"

REFERS TO CROSS SECTION DESIGNATION. THE

NUMBER "S2" REFERS TO THE SHEET NUMBER

WHERE THE SECTION IS SHOWN.

INDICATES DETAIL LOCATION. THE NUMBER 6

REFERS TO THE DETAIL DESIGNATION. THE

NUMBER S2 REFERS TO THE SHEET NUMBER

WHERE THE DETAIL IS SHOWN.

CENTERLINE

MAJOR 5 FT CONTOUR INTERVAL

WITH ELEVATION IN FEET

MINOR 1 FT CONTOUR INTERVAL

NEW CONCRETE

EXISTING

CONCRETE

NATURAL GROUND

FILTER SAND

STEEL

EMBANKMENT

BACKFILL

SELECT FILL

NORTH ARROW

CONTROL

POINT/MONUMENT

BEDROCK

CUT SLOPE

FILL SLOPE

STRUCTURAL

SLOPE

LEGEND

PROPERTY BOUNDARY

APPROX. WATER OR WETLANDS LIMITS

DRAIN GRAVEL

RIPRAP

BACKFILL

CONCRETE

GROUT

BASECOURSE

A.B. = ANCHOR BOLT

ACB = ARTICULATED CONCRETE BLOCKS

ADDL = ADDITIONAL

APPROX. = APPROXIMATELY

B.O.H. = BOTTOM OF HOLE

BF = BOTTOM FACE

BL = BOTTOM LAYER

BM = BENCHMARK

BR = BOTTOM ROW

BTWN = BETWEEN

CFS = CUBIC FEET PER SECOND

CI - CAST IRON

CJ = CONSTRUCTION JOINT

CLR. = CLEAR

CMP = CORRUGATED METAL PIPE

CMU = CONCRETE MASONRY UNIT

CONC. = CONCRETE

CP = CONTROL POINT

CRJ = CONTROL JOINT

CTJ = CONTRACTION JOINT

CTR. = CENTER OR CENTERS

℄ = CENTERLINE

D = NORMAL DIAMETER OF

DI = DUCTILE IRON

DIPS = DUCTILE IRON PIPE SIZE

DR = DIMENSION RATIO

D/S = DOWNSTREAM

db = NOMINAL DIAMETER

DIA. = DIAMETER

DEMO = DEMOLISH

DET. = DETAIL

DIAG. = DIAGONAL

DWG. = DRAWING

DWL. = DOWEL

E. = EASTING

EA. = EACH

EC = EACH CORNER LENGTHS OF BARS

EF = EACH FACE

EJ = EXPANSION JOINT

EL = ELEVATION (IN FEET)

ELL = HDPE ELBOW

EMBED = EMBEDDED/EMBEDMENT

EQ. SPC. = EQUALLY SPACED OR EQUAL

SPACES

ER = EACH ROW

ES = EACH SIDE

EW = EACH WAY

EXIST = EXISTING

F.G. = FINAL GRADE

FF = FAR FACE

EL. = FINISH

FLG = FLANGE

FR = FAR ROW

FS = FAR SIDE REINFORCING BAR

FTG. = FOOTING

GA = GAUGE

GALV. = GALVANIZED

GR. = GRADE

GRP = GLASSFIBER REINFORCED PLASTICS

H = HORIZONTAL

HDPE = HIGH DENSITY POLYETHYLENE

H.R. = HAND RAIL

HK. = HOOK

HSS = HOLLOW STRUCTURAL SECTION

I.D. = INSIDE DIAMETER

IF = INSIDE FACE

INV. = INVERT

IR = INSIDE ROW

Ld = DEVELOPMENT LENGTH

LCD = LEFT CHIMNEY DRAIN

LLV = LONG LEG VERTICAL

LOD = LEFT OUTLET DRAIN

LTD = LEFT TOE DRAIN

MAX. = MAXIMUM

MFR. = MANUFACTURER

MIN. = MINIMUM

MJ = MECHANICAL JOINT

ML = MIDDLE LAYER

MP = MONITORING POINT

MR = MIDDLE ROW

N. = NORTHING OR NORTH

NO. = NUMBER

NAVD = NORTH AMERICAN VERTICAL DATUM

NGVD = NATIONAL GEODETIC VERTICAL

DATUM

NHWL = NORMAL HIGH WATER LINE

N.T.S. = NOT TO SCALE

NF = NEAR FACE

NR = NEAR ROW EQ.

NS = NEAR SIDE

O.C. = ON CENTER

O.D. = OUTSIDE DIAMETER

O.H.P. = OVER HEAD POWER

OF = OUTSIDE FACE

OPP = OPPOSITE

OR = OUTSIDE ROW

PC = POINT OF CURVATURE

P.D. = PLAIN DOWELS

P.I. = POINT OF INTERSECTION

P.R.C. = POINT OF REVERSE CURVATURE

PT = POINT OF TANGENCY

PE = PLAIN END

⅊ = PLATE

PLCS = PLACES

PROJ = PROJECTION

PVC = POLY VINYL CHLORIDE

R = RADIUS

RCD = RIGHT CHIMNEY DRAIN

REQD = REQUIRED

REINF. = REINFORCEMENT

ROD = RIGHT OUTLET DRAIN

RSP = RIVETED STEEL PIPE

RTD = RIGHT TOE DRAIN

S = SLOPE

SCH. = SCHEDULE

SDR = STANDARD DIMENSION RATIO

SECT. = SECTION

SEO = COLORADO DIVISION OF WATER

RESOURCES, OFFICE OF THE STATE

ENGINEER

SIM. = SIMILAR

SPC. = SPACE OR SPACES

SPY. = SPILLWAY

SQ. = SQUARE

SS = STAINLESS STEEL

STA. = STATION

STD = STANDARD

STL. = STEEL

SYM. = SYMMETRICAL

T.&B. = TOP AND BOTTOM

T.O. = TOP OF

T.O.W. = TOP OF WALL

TF = TOP FACE

THK = THICK

THRD = THREADED

TL = TOP LAYER

TR = TOP ROW OF REINFORCING BAR

TYP. = TYPICAL

U.N.O. = UNLESS NOTED OTHERWISE

U/S = UPSTREAM

UV = UNIFORMLY VARYING

V = VERTICAL

VCP = VITRIFIED CLAY PIPE

W = WIDE FLANGE STRUCTURAL BEAM

W/ = WITH

W/O = WITHOUT

WP = WORK POINT

W.S. = WATER SURFACE

W.S.A. = WATER STOP TYPE A

WSP = WELDED STEEL PIPE

WTP = WATER TREATMENT PLANT

SURVEY NOTES:

1. TOPOGRAPHIC SURVEY DATA WAS COLLECTED BY HOLLYBECK

SURVEYING AND ENGINEERING, INC. ON JULY 14, 2020

2. HORIZONTAL PROJECT COORDINATES ARE NORTH DAKOTA STATE

PLANE SOUTH, NORTH AMERICAN DATUM 1983 (NAD 83). PROJECT

VERTICAL CONTROL IS BASED ON NORTH AMERICAN VERTICAL DATUM

1988 (NAVD 88)

DESIGNED DRAWN CHECKED DATE DRAWING NO. SHEET

OF

SUB-SHEETBONE HILL CREEK

BONE HILL DAM REMOVAL

CBM SAA JJT 01/22/2021 2 5

ABBREVIATIONS, LEGEND, AND SITE ACCESS G2

R:

\1

0\

\1

2.

_B on eH ill_

Re m ov al

\9 _D ra w in gs

\C

AD

F ile s\

IF

C\ Sh ee tF ile s\

-0

-0

8-

3:

pm

S co tt X

RE

FS

: 2

3_

Al lP oi nt s;

J

JT

_s ta m p

JJ

T_ sig

ABBREVIATIONS PRIVATE PROPERTY

AND ACCESS ROAD

NOTES:

1. ACCESS ROAD IS ON PRIVATE PROPERTY. GATES MUST BE CLOSED UPON ENTRY

AND EXIT DUE TO CATTLE.

STAGING AND

STOCKPILE AREA

JO

HN

JO

SEPH TREACY

III

CO

LO

RADO L CENSED

I

PROFESSIONAL ENGINE

ER

47781

2/8/2021

AutoCAD SHX Text

2+00

3+00

4+00

5+00

BH

B1

BH

B2

BH

B3

BH

B4

BORING LOCATION TABLE

Point #

B1

B2

B3

B4

Northing

326807.11

326880.56

326917.02

326990.46

Easting

2380937.57

2380961.20

2380960.44

2380984.07

Elevation

1644.97

1645.17

1645.56

1645.58

0 20 50 100 150 Scale in Feet

SPILLWAY

TRAINING DIKE

AUXILIARY

SPILLWAY

BONE HILL

DAM

CMP SERVICE

SPILLWAY OUTLET

BONE HILL

CREEK LAKE

DESIGNED DRAWN CHECKED DATE DRAWING NO. SHEET

OF

SUB-SHEETBONE HILL CREEK

BONE HILL DAM REMOVAL

CBM SAA JJT 01/22/2021 3 5

EXISTING PLAN AND SECTION C1

R:

\1

0\

\1

2.

_B on eH ill_

Re m ov al

\9 _D ra w in gs

\C

AD

F ile s\

IF

C\ Sh ee tF ile s\

-0

-0

8-

3:

pm

S co tt X

RE

FS

: 2

3_

Al lP oi nt s;

J

JT

_s ta m p

JJ

T_ sig

EROSION/

HEADCUTTING

IN SPILLWAY

OUTLET DISCHARGE

CHANNEL

DOWNSTREAM

CHANNEL

A C1

SECTION

OUTLET STRUCTURE

C1 A

0 5 10 15 Scale in Feet

10.0'

10.0'

36" DIA. CMP

APPROX. 65'

12" D50 RIPRAP

ON 6" BEDDING

48" - 12 SECTION

CMP RISER

12" D50 RIPRAP

ON 6" BEDDING

2.0'

RIPRAP

DRAIN

COMPACTED

BACKFILL

6" DIA. TOE DRAIN

STA. 1+88 TO 4+88±

NOTES:

1. CONTOURS UPSTREAM OF CMP HEADWALL WERE INTERPOLATED BASED ON

GROUND CONDITIONS.

2. GABION ROCK BASKETS ARE SPREAD OUT ALONG AUXILIARY SPILLWAY CHANNEL.

3. REMOVE AND DISPOSE OF EXISTING CMP RISER AND OUTLET PIPE.

4. SALVAGE AND REUSE UPSTREAM SLOPE RIPRAP FOR BREACH TO THE EXTENT

POSSIBLE.

5. EXCAVATE AND REMOVE TOE DRAIN WITHIN THE EXCAVATION LIMITS. ABANDON

AND GROUT TO FILL REMAINING TOE DRAIN WITH 3,000 PSI GROUT.

6. EXCAVATED RANDOM FILL TO BE PLACED AND GRADED IN THE AUXILIARY SPILLWAY

CHANNEL. SLOPE 3H:1V OR FLATTER.

INV. EL. 1634.14

OUTLET INV. EL. 1628.63

JO

HN

JO

SEPH TREACY

III

CO

LO

RADO L CENSED

I

PROFESSIONAL ENGINE

ER

47781

2/8/2021

1+00

2+00

3+00

4+00

5+00

EL

EV

AT

IO

N (F

EE

T)

EL

EV

AT

IO

N (F

EE

T)

0+00 0+40

DESIGNED DRAWN CHECKED DATE DRAWING NO. SHEET

OF

SUB-SHEETBONE HILL CREEK

BONE HILL DAM REMOVAL

CBM SAA JJT 01/22/2021 4 5

GENERAL PLAN OF MODIFICATIONS C2

R:

\1

0\

\1

2.

_B on eH ill_

Re m ov al

\9 _D ra w in gs

\C

AD

F ile s\

IF

C\ Sh ee tF ile s\

-0

-0

8-

3:

pm

S co tt X

RE

FS

: 2

3_

Al lP oi nt s;

J

JT

_s ta m p

JJ

T_ sig

0 20 50 100 150 Scale in Feet

36" DIA. CMP

(TO BE REMOVED)

EROSION AREA TO BE

FILLED W/ EMBANKMENT

MATERIAL

ACCESS ROAD

LOW WATER

CROSSING

NOTES:

1. EXCAVATED EMBANKMENT FILL WILL BE PLACED AND

GRADED IN THE EROSION HEADCUTTING AREAS

WITHIN THE AUXILIARY SPILLWAY.

2. SLOPE HEADCUTTING AREAS 3H:1V FOR CATTLE.

140.0'

260.0'

210.0'

160.0'LIMITS OF SITE

DISTURBANCE

LIMITS OF SITE

DISTURBANCE

STAGING AND

STOCKPILE AREA

200.0'

100.0'

LIMITS OF

WETLANDS

LIMITS OF

WETLANDS

LIMITS OF

WETLANDS

MIN. 6"

STRIPPING

MIN. 4.0'

EROSION SCARP

RANDOM FILL

A C2

TYPICAL SECTION

EROSION SCARP

C2 A

JO

HN

JO

SEPH TREACY

III

CO

LO

RADO L CENSED

I

PROFESSIONAL ENGINE

ER

2+

3+ 004+

5+

2+

.2

-5.0H:1V -5.0H:1V

-5 .0

-1

.0

CP

CP

CP

CP

EL

EV

AT

IO

N (F

EE

T)

EL

EV

AT

IO

N (F

EE

T)

PROFILE VIEW OF EMBANKMENT BREACH

1+00 2+00 3+00 4+00 4+50

EL

EV

AT

IO

N (F

EE

T)

EL

EV

AT

IO

N (F

EE

T)

2+54

0.0 20.0 40.00.0-20.0-40.0

TEMPORARY CONTROL POINT TABLE

Point #

CP1

CP2

CP3

CP4

Northing

326926.06

326923.89

326876.88

326874.71

Easting

2380963.00

2380974.80

2380953.98

2380965.79

Elevation

1635.15

1635.14

1635.15

1635.14

0 10 20 40 60 Scale in Feet

DESIGNED DRAWN CHECKED DATE DRAWING NO. SHEET

OF

SUB-SHEETBONE HILL CREEK

BONE HILL DAM REMOVAL

CBM SAA JJT 01/22/2021 5 5

BREACH PLAN, PROFILE, AND CROSS-SECTION C3

R:

\1

0\

\1

2.

_B on eH ill_

Re m ov al

\9 _D ra w in gs

\C

AD

F ile s\

IF

C\ Sh ee tF ile s\

-0

-0

8-

3:

pm

S co tt X

RE

FS

: 2

3_

Al lP oi nt s;

J

JT

_s ta m p

JJ

T_ sig

PRECONSTRUCTION

GROUND SURFACE

50.0'

ST

A.

.1

" D

IA

. C M

P

FLATTER

FLATTER

LOW WATER

CONCRETE CROSSING

PLAN VIEW OF

EMBANKMENT BREACH

PRECONSTRUCTION

GROUND SURFACE

EL. 1635.15

12.0'

-0.1% -1.0%

36" DIA. CMP

4.0'

2.0'

BREACH INV.

EXCAVATE 2' BELOW PIPE AND

BACKFILL AND COMPACT W/

SUITABLE EMBANKMENT FILL

C3

DETAIL

OUTLET REMOVAL

C3

0 5 10 15 Scale in Feet

10.0'

C3

-0.1% -1.0% -5.0%

GABION ROCK ON

FILTER FABRIC6" BEDDING

CONTROL SILL

EL. 1635.15

12.0' 5.0'

DETAIL

LOW WATER CROSSING

C3

0 5 10 15 Scale in Feet

5.0'

24" THICK TYPE I RIPRAP

OVER 6" BEDDING

5.0'

24" THICK TYPE I RIPRAP

OVER 6" BEDDING

1.0'

2.5'

1.0'

DETAIL

LOW WATER CROSSING

C3

0 1 2 4 6 Scale in Feet

#5@12 EW

C3

4.0'

6" ROADBASE FROM

CROSING TO GRADE

6" ROADBASE 3,500 PSI

CONCRETE

NOTES:

1. LOW WATER CROSSING CONCRETE WILL TRANSITION TO ROADBASE ON SIDE

SLOPES TO GRADE.

2. CUT SLOPES TO BE MATTED AND SEEDED BOTH UPSTREAM AND DOWNSTREAM.

3. TEMPORARY CONTROL POINTS ARE FOR CONSTRUCTION ONLY AND REPRESENT

THE EXTENT OF THE BREACH LOCATION AND ELEVATION.

4. SIDE SLOPES TO BE CONSTRUCTED AT 5H:1V MINIMUM. SLOPES MAY BE

FLATTENED AT THE DISCRETION OF THE LAND OWNER AND FWS.

6" ROADBASE

(TYP.)

CUT SLOPES TO

BE SEEDED

NATIVE UPLAND

SEED MIX

LIMITS OF SITE

DISTURBANCE

TYPE I RIPRAP

AND GABION ROCK

1.5

1.5

-5.0%

TYPE I RIPRAP

5 OR5 OR

JO

HN

JO

SEPH TREACY

III

CO

LO

RADO L CENSED

I

PROFESSIONAL ENGINE

ER

Appendix C Geotechnical Report

REPORT C OVER PAGE

Geotechnical Exploration Report

Dam Exploration

Lamoure County, North Dakota

August 5, 2020

Terracon Project No. M1205033

Prepared for:

W. W. Wheeler & Associates, Inc.

Englewood, CO

Prepared by:

Terracon Consultants, Inc.

West Fargo, ND

Terracon Consultants, Inc. 860 9 th Street NE, Unit K West Fargo, ND 58078

P (701) 282 9633 F (701) 282 9635 terracon.com

REPORT C OVER LETTER TO SIGN

August 5, 2020

W. W. Wheeler & Associates, Inc.

3700 S. Inca Street

Englewood, CO 80110

Attn: Mr. John Treacy, III P.E.

P: (303) 761 4130

E: john.treacy@wwwheeler.com

Re: Geotechnical Exploration Report

Dam Exploration

Bone Hill Creek National Wildlife Refuge

Lamoure County, North Dakota

Terracon Project No. M1205033

Dear Mr. Treacy:

We have completed the Geotechnical Exploration services for the above referenced project. This study was performed in general accordance with Terracon Proposal No. PM1205033 dated July

1, 2020. This report presents the findings of the subsurface exploration for the proposed project.

We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

Alex L. Sprunk, P.E. Chad A. Cowley, P.E.

Geotechnical Group Manager Senior Engineer

Responsive ■ Resourceful ■ Reliable 1

REPORT TOPICS

INTRODUCTION

SITE CONDITIONS

PROJECT DESCRIPTION

GEOTECHNICAL CHARACTERIZATION

GENERAL COMMENTS

FIGURES

Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referenced section heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the

GeoReport logo will bring you back to this page. For more interactive features, please view your project online at client.terracon.com.

ATTACHMENTS

EXPLORATION AND TESTING PROCEDURES

SITE LOCATION AND EXPLORATION PLANS

EXPLORATION RESULTS

SUPPORTING INFORMATION

Note: Refer to each individual Attachment for a listing of contents.

http://client.terracon.com/

Responsive ■ Resourceful ■ Reliable 1

INTRODUCTION

Geotechnical Exploration Report

Dam Exploration

Bone Hill Creek National Wildlife Refuge

Lamoure County, North Dakota Terracon Project No. M1205033

August 5, 2020

INTRODUCTION

This report presents the results of our subsurface exploration and laboratory testing services performed for the proposed dam removal project at Bone Hill Creek National Wildlife

Refuge in Lamoure County, North Dakota. The purpose of these services is to provide information relative to:

■ Subsurface soil conditions ■ Groundwater conditions

The geotechnical exploration Scope of Services for this project originally included the advancement of four test borings to depths of 15 feet below existing site grades. While on site, W. W. Wheeler amended the fieldwork scope and requested we advance all four borings to a depth of approximately 20 feet below existing grade.

Maps showing the site and boring locations are shown in the Site Location and Exploration

Plan sections, respectively. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included on the boring logs and/or as separate graphs in the Exploration Results section.

SITE CONDITIONS

The following description of site conditions is derived from our site visit in association with the field exploration and our review of publicly available geologic and topographic maps.

Item Description

Parcel Information

The project is located at Bone Hill Creek National Wildlife Refuge in

Lamoure County, North Dakota.

Latitude: 46.5512° N, Longitude: 98.8605° W (approximate)

See Site Location

Existing

Improvements

Existing wildlife refuge

We understand there is an existing dam on the east side of Bone Hill Creek

Lake. Detailed information regarding the dam (height, width, etc.) were not provided.

Dam Exploration ■ Lamoure County, North Dakota

August 5, 2020 ■ Terracon Project No. M1205033

Responsive ■ Resourceful ■ Reliable 2

Item Description

Current Ground Cover Moderately vegetated earthen cover

Existing Topography

Rolling terrain; from the top of the dam, the ground surface slopes downward to the east and west. Top of the dam is at approximate elevation 1645.

PROJECT DESCRIPTION

We understand the dam at Bone Hill Creek National Wildlife Refuge will be removed and the site restored to near original conditions. It is our understanding some of the existing embankment fill will be used to repair eroded areas adjacent to the dam. W. W. Wheeler requested us to provide geotechnical exploration (drilling and sampling) services at four points along the existing dam on the east side of Bone Hill Creek Lake which is located on the Bone Creek National Wildlife Refuge.

W. W. Wheeler also requested Terracon to provide laboratory testing on select samples.

GEOTECHNICAL CHARACTERIZATION

We have developed a general characterization of the subsurface conditions based upon our review of the subsurface exploration, laboratory data, geologic setting and our understanding of the project. This characterization is termed GeoModel. Conditions encountered at each exploration point are indicated on the individual logs. The individual logs can be found in the

Exploration Results section and the GeoModel can be found in the Figures section of this report.

As part of our analyses, we identified the following model layers within the subsurface profile. For a more detailed view of the model layer depths at each boring location, refer to the GeoModel.

Model Layer Layer Name General Description

1 Fill 1 Sandy lean clay mixture - grayish brown and gray, trace gravel, occasional cobbles

2 Fill 2 Sandy lean clay mixture - dark/light gray and black, trace gravel, occasional cobbles, some decayed plant vegetation

3 Fill 3 Buried topsoil - organic clay or sandy silt, dark gray to black, some decayed plant vegetation

4 Fill 4 Silty sand or clayey sand - trace gravel, gray to black, medium to fine grained, waterbearing

5 Sand

Silty or clayey sand - grayish brown to gray, variable contents of gravel, occasional cobbles, fine to coarse grained, medium dense, waterbearing

Responsive ■ Resourceful ■ Reliable 3

Model Layer Layer Name General Description

6 Gravel Poorly graded gravel with silt and sand – grayish brown, fine to coarse grained, waterbearing, occasional cobbles

7 Clay Sandy lean clay - grayish brown to gray, variable contents of gravel, occasional cobbles, medium stiff to very stiff

Due to the variability of soils encountered in the upper 15 feet of the soil borings, it was difficult to identify an accurate transition between fill and native soils. It is possible some of the soils we identified in the boring logs as “fill”, between depths of 10 and 15 feet below grade, are instead disturbed native soils.

Groundwater

The boreholes were observed while drilling for the presence and level of groundwater. The water levels observed in the boreholes can be found on the boring logs in Exploration Results and are summarized below.

Boring Number Approximate Depth to Groundwater while Drilling and Sampling (feet)

B-1 10

B-2 10

B-3 10

1. Below ground surface.

Groundwater was not observed in the remaining boring while drilling, or for the short duration the borings could remain open. However, this does not necessarily mean the boring terminated above groundwater, or the water levels summarized above are stable groundwater levels. Due to the low permeability of some of the soils encountered in the borings, a relatively long period may be necessary for a groundwater level to develop and stabilize in a borehole. Long term observations in piezometers or observation wells sealed from the influence of surface water are often required to define groundwater levels in materials of this type.

Groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the…