W912QR25R0016_CERT_Final_Vol6_ ProjGIR_13of16_F-0000.pdf

Solicitation For Rough River Dam Safety Modification Project Phase II - New Outlet Works and Cutoff Wall, Rough River Reservoir, Falls of Rough, KY

P2: 145870

Design-Bid-Build

Geotechnical Information Report (GIR) Vol. 6 (13 of 16) Appendix F

Certified Final

20 December 2024

W912QR25R0016

ARIMS: 1200

Disposition: Permanent

W912QR25R0016_CERT_Final_Vol6_ ProjGIR_13of16_F-0000

Rough River Dam Geotechnical Data Report for Tunnel Construction

Volume 6: Project GIR

Appendix F - Analysis of Downstream Cofferdam and Dewatering (13 of 16)

ROUGH RIVER, FALLS OF ROUGH, KY

LOUISVILLE DISTRICT, LRD DIVISION

Appendix A

SYNOPSIS OF CONSTRUCTION HISTORY AND PERFORMANCE

Appendix B

BORING LOCATION PLANS AND BORING LOGS

Appendix C

SOIL AND ROCK TESTING AND ANALYSES BY INVESTIGATION

Appendix D

INSTRUMENTATION AND MONITORING

Appendix E

ANALYSES OF THE UPSTREAM FILTER AND DEWATERING

Appendix F

ANALYSES OF THE DOWNSTREAM COFFERDAM AND

DEWATERING

Appendix G

ANALYSES OF DOWNSTREAM FILTER FOR STILLING BASIN ABANDONMENT

Appendix H

ANALYSES OF CUTOFF WALL WORK PLATFORM

Appendix I

ANALYSES OF UPLAND DISPOSAL AREA AND ARCHERY BERM

Excavation Dewatering and Seepage Control

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DOWNSTREAM COFFERDAM EXCAVATION DEWATERING

1. Background The area to be excavated for the stilling basin construction will encounter a relatively thick sand layer that would readily transmit water into the excavation; therefore, a sheet pile cofferdam was determined the most logical choice since it can provide flooding protection up to the risk-based elevation of 453.5 while at the same time greatly reducing seepage within the foundation. To facilitate easier muck removal from the tunnel construction, the excavation will pause at elevation 437 to coincide with the tunnel invert, and then proceed down to elevation 425 once the tunnel is complete.

2. Design Intent The intent of the sheet pile wall is to limit seepage into the excavation and provide a moderate level of flood protection. To this end, it was determined that the piles should be driven to refusal into competent, low permeability rock to minimize flow under the wall. To further limit seepage, several sealants were evaluated for use as interlock fillers.

3. Estimation of flow through and beneath sheet pile wall Flow past the sheet pile wall, both through the interlocks and beneath the tips, was estimated using analytical calculations and SEEP/W computer modeling, and the parameters necessary for the analyses were determine based on field observations and laboratory data from collected soil samples.

3.1. Model Setup/Determination of Parameters

Soil hydraulic conductivity The sheet pile wall will be advanced through two classifiably different soil types for which their hydraulic conductivities were determined using both their USCS classifications and lab testing. The overlying soil is clay with silt and sand while the underlying material is primarily sand with varying percentages of silt and clay that has the potential in areas to act as an aquifer.

There is a limited amount of site-specific permeability testing available to help estimate the hydraulic conductivity of the soils. The permeability of the overlying clay (which is similar to the dam embankment soil) was estimated using the installation records and the 1998 time lag results of six piezometers (PZ-6, PZ-8, PZ-10, PZ-12, PZ-22, PZ-19, and PZ-23). The permeability of the sand layer was estimated using the installation records and the 1998 time lag results of four piezometers (WP-1, PZ- 2, PZ-7, and PZ-18). The calculated permeabilities for the overlying clay layer ranged from 1.10 x 10-8 ft/s to 5.03 x 10-8 ft/s with an average of 2.44 x 10-8 ft/s and standard deviation of 1.18 x 10-8 ft/s. The calculated permeabilities for the underlying sand layer ranged from 5.64 x 10-7 to 1.83 x 10-5 ft/s with an average of 5.73 x 10-6 ft/s and a standard deviation of 8.44 x 10-6 ft/s. The site-specific permeability testing represented only a small area that was located upstream of the area where the dewatering system will be installed, and since soil properties can vary significantly across alluvial deposits, established values from Figure 2-5 in EM 1110-2-1901 (shown as Figure 1 here) were used and the units converted.

Silt/Clay: ~10-5 cm/s >>>>>> (3.3 x 10-6 ft/s) Sand/Silt: ~10-3 cm/s >>>>>> (3.3 x 10-4 ft/s) Clean Sands: 10-1-10-2 cm/s >>>> (3.3 x 10-2 – 3.3 x 10-3 ft/s)

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Figure 1: EM 1110-2-1901 Fig 2-5 Approximate coefficient of permeability of soils and rocks

This is an alluvial deposit and experience has shown that properties within alluvial deposits can vary significantly (a boring in one location could indicate a dirty sand while a boring less than 50 feet away could show a clean sand). It was found in a previous project similar to this one that the vast majority of the flow originated from only about 10 to 25 percent of the overall system length. The log of boring ADC-1810 shows this variation with layers of clayey sand, silty sand, and generally clean sand. Given the known variability of alluvial deposits in conjunction with the limited number of borings along the proposed sheet pile wall alignment, assignment of an individual permeability value was not possible.

Boring ADC-1810 shows that underlying sand zone is composed of layers of materials with differing properties including clayey silty sand and cleaner, fine grained sand. It appears that most of the underlying sand layer has sands with fines rather than cleaner material. Figure 2 and Figure 3 show portions of the boring log from ADC-1810 with various material types.

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Figure 2: Portion of boring log ADC-1810 showing overlying clay layer and top of underlying sand layer

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Figure 3: Portion of boring log ADC-1810 showing various materials in underlying sand layer

Assumptions:

The hydraulic conductivity of the overlying clay was set at 5 x 10-7 ft/s which is immediately between the site-specific testing values and the EM 1110-2-1901 values.

The hydraulic conductivity for the underlying sand layer was estimated as falling between 1.4 x 10-5 and

1.4 x 10-4 ft/s. The estimate was skewed more towards the EM-1110-2-1901 rather than the testing values based on the limited area of site-specific testing and known variability of alluvial deposits. This yields a more conservative analysis for estimate of seepage.

It is likely that the permeability of the clay layer also varies significantly; however, its permeability is several orders of magnitude lower than the underlying sand layer so it will not meaningfully alter the resulting seepage estimates. A constant value of 5x10-7 ft/s was used in all model runs, which is between the field-testing derived values and what is found in literature.

Rock Hydraulic Conductivity Rock permeabilities were discussed with the LRL geologist. Shale and sandstone layers that the sheet pile wall will key into can be assumed to be impermeable; as a result, very low hydraulic conductivity values were assigned to these layers (1 x 10-10 for sandstone and 1 x 10-12 for shale). Intact limestone is

F-5 nearly impermeable but karstic zones have the potential to pass enormous volumes of water, particularly when the features are not infilled. Weathered layers, with hydraulic conductivities several orders of magnitude higher than intact rock, were added for each rock type following a discussion with the LRL project team.

Table 1: Summary of Permeabilities used in Models

Material Saturated Hydraulic Conductivity (ft/s)

Lean clay with silt and sand (clay layer) 5.0 x 10-7 Sand- with silt and clay (low permeability sand layer value) 1.4 x 10-5

Sand- with silt and clay (high permeability sand layer value) 1.4 x 10-4

Sandstone 1.0 x 10-10

Shale 1.0 x 10-12

Weathered Shale 1.0 x 10-9 Weathered Sandstone 5.0 x 10-8

Limestone (intact) 1.0 x 10-10

Limestone (weathered/karstic) 1.0 x 10-2

3.2. Model Geometry

Based on the profile view of the sheet pile wall (Figure 4), three distinct zones can be identified for seepage models.

Figure 4: Profile view of sheet pile wall

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1. Zone 1 represents the portion of the legs where the sand layer pinches out and the rock is at higher elevations (Sta. 0+00 to 0+80 and Sta. 7+20 to 7+80).

2. Zone 2 represents the main segment of the sheet pile wall parallel to the existing outlet channel.

The rock along this segment is around elevation 400 (Sta. 2+20 to 6+20).

3. Zone 3 represents the portion of the legs where the rock elevation is approximately 420 (Sta.

0+80 to 2+20 and Sta. 6+20 to 7+20).

Figure 5: Plan view of sheet pile wall alignment

The LRL project team provided cross-sections at the locations shown in Figure 5 with the existing ground surface elevation, proposed excavation, and the top of rock surface. The top of rock was verified by the LRL geologist using borings in the area and site-specific knowledge. No soil strata elevations were provided on the cross-sections and boring data to estimate them was limited. Boring ADC-1810 was used as the basis for soil strata elevations at each cross-section. From the ground surface to approximately 440 was assumed to be the clay layer. The sand layer was placed from elevation 440 to the top of rock.

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Flow through the sheet pile wall section was modeled by flow through a slurry wall of equivalent hydraulic conductivity. A slurry wall of 2-foot thickness was placed in the approximate location of where the sheet pile wall is to be constructed. The process used to determine the equivalent hydraulic conductivity of the slurry wall is discussed in Section 3.5.

Images of the cross-sections are shown in Figure 6, Figure 7, and Figure 8. Note, regions are included in the excavated area as some models were run on the unexcavated slope as an initial run. These regions were modeled as empty zones in further models which is equivalent to them not existing.

Figure 6: Cross sections for Zone 1 model (Material types - top; SEEP/W boundaries – bottom)

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Figure 7: Cross sections for Zone 2 model (Material types - top; SEEP/W boundaries – bottom)

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Figure 8: Cross sections for Zone 3 model (Material types - top; SEEP/W boundaries – bottom)

3.3. Estimate of flow through sheet pile interlocks (Analytical approach) Flow through the sheet pile interlocks was estimated using the approaches described in “Impervious steel sheet pile walls: Design and Practical approach” (ArcelorMittal, 2014). This reference, based on research by ArcelorMittal and Deltares (Delft Geotechnics), included an explanation of the theory to describe leakage through joints in sheet pile (SSP) walls and data on in situ tests conducted on SSP walls. The rate of seepage through SSP walls with Larssen type interlocks for various filler materials, as well as empty and welded interlocks, was evaluated in that study.

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Unlike a porous medium, such as a slurry wall, seepage through SSP walls cannot be calculated with aid of Darcy’s law, so researchers introduced the concept of “Interlock Resistance”. Since the discharge through the interlock joints is proportional to the pressure difference on each side of the SSP, this proportionality can be related by a constant, ρ (inverse interlock resistance).

q(z) = ρ ∙ ∆p(z) γw q(z) = discharge per unit of interlock length Δp(z) = pressure drop at level z p = inverse interlock resistance γw = unit weight of water

For a single interlock, this relationship is represented by the following equation.

Q1 = ρ ∙ H ∙ (0.5H + h)

H = Groundwater height above datum on retained side of SSP minus groundwater height above datum on excavated side H = Groundwater height above datum on excavated side of SSP

The total number of interlocks in the SSP wall can be found with the following relationship.

n = L b n = number of interlocks L = total length of SSP B = system width of pile

The total discharge through the wall (Q) is:

Q = n ∙ Q1

ArcelorMittal and HOESCH provide values for the interlock resistance for various watertightening systems as well as empty and welded interlocks.

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Table 2: Seepage Resistance for various water-tightening solutions in SSP wall interlocks Watertightening Solution

(on 575mm or 600mm pile section)

Interlock Resistance (m/s) Interlock Resistance (ft/s) Reference

Empty Interlock >1000 x 10-10 3.28 x 10-7 ArcelorMittal

Beltan Plus or Arcoseal <600 x 10-10 1.97 x 10-7 ArcelorMittal

ROXAN Plus or AKILA 0.3-0.5 x 10-10 9.84 x 10-11 - 1.64 x 10-10 ArcelorMittal

SIRO 88 6 x 10-8 1.97 x 10-7 HOESCH

HOESCH Interlock sealing 1.8 x 10-10 5.91 x 10-10 HOESCH

For the empty interlock, the value at a 150kPa (3132 psf), pressure differential was 4500 x 10-10 m/s (1.48 x 10-6 ft/s). The maximum hydrostatic pressure at Rough River is estimated at 50 kPa (970 psf), which represents a water drawdown of 12 feet. Given that the interlock resistance value increases with increasing hydrostatic pressure, the lowest value given for empty interlocks was used in the calculations/modeling.

The water-tightening solutions were summarized into 3 categories:

Empty interlocks (No sealant): ρ>3.28 x 10-7 ft/s Higher-permeability sealants: (Beltahn, Arcoseal, SIRO 88): Average ρ=1.97 x 10-7 ft/s Lower-permeability sealants: (Roxan, Akila, HOESCH): Average ρ=3.61 x 10-10 ft/s

3.4. Analytical Model Results

Analytical results are summarized in Table 3 and the full calculations are included in the appendix.

Table 3: Summary of analytical calculations

Model

Total Flow through SSP wall (gpm)

Empty Interlocks

Interlocks filled with ‘higher permeability’ sealant

Interlocks filled with ‘lower permeability’ sealant Analytical Calculations 44.77 26.86 0.05

The analytical calculations represent a simplified analysis that does not account for many key parameters that the Seep/W models can include. These parameters include the various soil strata, potential flow below the wall, and the fact that there is an offset between the excavation edge and the sheet pile wall (analytical calculations assume that the wall is exposed against the excavation). The model accounts for these factors and is recommended for analysis of the sheet pile wall design.

3.5. Estimate of flow through sheet pile interlocks: Modeling approach ArcelorMittal (2014) describes an alternate method of determining the seepage through SSP interlocks where the SSP is converted to a slurry wall with equivalent permeability. This allowed for the use of

F-12 seepage modeling software (SEEP/W) to estimate the seepage through the wall. The relationship between the interlock resistance and equivalent slurry wall hydraulic conductivity is:

k d = ρ b k = hydraulic conductivity of slurry wall d = thickness of equivalent slurry wall ρ = inverse interlock resistance b = system width of pile

Converting the interlock resistance values for the three categories of water-tightening solutions to equivalent hydraulic conductivities for a 2-foot thick slurry wall gives the following:

Empty Interlocks: k=1.04 x 10-7 m/s (3.41 x 10-7 ft/s) Higher-permeability sealants: k=5.55 x 10-8 m/s (1.82 x 10-7 ft/s) Lower-permeability sealants: k=1.07 x 10-10 m/s (3.51 x 10-10 ft/s)

3.6. Flow beneath the Sheet pile wall

The design intent is to drive the sheet pile wall through the soil and embed it fully into impermeable rock.

Boring ADC-1810 indicates that the soil strata consists of clay and sand layers. A layer of weathered sandstone (believed to be an alluvial deposit/basal gravel) lies immediately above the shale bedrock (Elwren Shale). Discussions with a sheet pile wall manufacturer indicated that wall panels could generally be driven successfully to SPT refusal which occurred at elevation 399.3, about 1 foot into the shale.

Despite the design intent, and SPT data indicating the feasibility of driving the sheet pile wall into competent rock, there is potential for gaps to exist below the wall. Proper installation techniques and quality control will be essential to ensuring that the wall is fully embedded in rock. Regardless of quality control, it is likely that some “windows” or gaps would be present under wall, and while this would be more likely along the legs where the rock slopes up from elevation 400 to 450 (an average slope of more than 20 percent), it is also possible beneath Zone 2, particularly if there are large rock within the alluvial deposits overlying the shale. Weathered rock may be harder than anticipated meaning that the sheet pile wall may not be able to fully penetrate the weathered layer. Several models were completed to account for these possibilities and to estimate the additional seepage passing beneath the wall due to gaps below the sheet pilingl. These models include:

• SSP fully embedded into impermeable rock

• 2-foot gap of sandy soil below SSP wall

• 1-foot gap of sandy soil below SSP wall

• SSP wall fully penetrates soil layers but a 5-foot layer of permeable weathered shale remains below the tip elevation

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A “no-wall” model was also analyzed to estimate the total seepage-reduction supplied by the alternative seepage control measures.

3.7. Analysis of Seep/W Model Results

Three cross-sections, representing different zones along the sheet pile wall, were modeled as shown and described in Section 3.2. The models were used to estimate the effectiveness of various seepage control features and placement scenarios under the following circumstances.

1. For each cross-section the following situations were evaluated twice, once for using the higher sand zone permeability value and once using the lower value.

a. Baseline (no sheet pile wall in place)

b. Sheet pile wall completely keyed into competent rock and no sealant in the interlocks

c. Sheet pile wall completely keyed into competent rock and higher-permeability sealant in interlocks

d. Sheet pile wall completely keyed into competent rock and lower-permeability sealant in interlocks

e. Sheet pile wall with 1-foot gap below and no sealant in interlocks

f. Sheet pile wall with 1-foot gap below and higher-permeability sealant in interlocks

g. Sheet pile wall rock with 1-foot gap below and lower-permeability sealant in interlocks

h. Sheet pile wall with 2-foot gap below and no sealant in interlocks

i. Sheet pile wall with 2-foot gap below and higher-permeability sealant in interlocks

j. Sheet pile wall rock with 2-foot gap below and lower-permeability sealant in interlocks

k. Sheet pile wall with 5-foot weathered rock below and no sealant in interlocks

l. Sheet pile wall with 5-foot weathered rock below and higher-permeability sealant in interlocks

m. Sheet pile wall rock with 5-foot weathered rock below and lower-permeability sealant in interlocks

2. The calculated seepage output from the model was converted from cfs/ft to cfs by multiplying the length of sheet pile wall assumed to be in each zone, as follows:

a. Zone 1 = 140 feet

b. Zone 2 = 400 feet

c. Zone 3 = 240 feet

3. Calculated segment flows (in cfs) were converted to gpm and the zoned results for each modeled condition were added together to get a total (raw) estimated seepage through the wall.

4. The seepage reduction for each modeled condition was calculated by dividing the condition’s modeled seepage by the baseline/no wall seepage.

5. Using the assumptions in Table 4, an overall estimated seepage reduction for each potential sheet pile wall alternative was calculated using a ‘weighted average’ approach.

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Table 4: Assumptions for seepage reduction calculation

Characteristic Percentage of

Characteristic Used in Calculation

Higher-permeability sand zone 30 Lower-permeability sand zone 70

Piling completely keyed into rock 60 Piling with 1-foot gap below 20 Piling with 2-foot gap below 10 Piling with 5-foot layer of weathered shale below 10

Percentage reduction in efficiency due to construction defects 10

6. The total maximum estimated seepage was calculated by applying overall estimated seepage reduction to the baseline/no wall value. A safety factor of 2 was applied.

The estimated seepage into the excavation without the sheet pile wall based on modeling is summarized in Table 5.

Table 5: Estimated seepage into excavation without sheet pile wall

Modeled Scenario Estimated Flow (gpm) Flow into excavation with higher-permeability sand zone 150.10

Flow into excavation with lower-permeability sand zone 19.45

Estimated flow into excavation based on assumptions of sand zone 58.65

The model calculated and combined seepage reduction estimates are summarized in Table 6 through Table 8. Full model results and calculations are included in the attached appendix.

Table 6: Estimated seepage reduction- no sealant in sheet pile wall joints

Modeled Scenario Higher-permeability sand zone

Lower-permeability sand zone

Combined reduction (based on sand zone assumptions)

Overall System Estimated

Reduction (based on assumptions)

Completely keyed into rock 80.51% 31.80% 46.42%

37.7% 1-foot gap below wall 50.08% 25.35% 32.77% 2-foot gap below wall 43.09% 23.13% 29.12% 5-foot weathered shale layer below wall 80.42% 31.62% 46.26%

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Table 7: Estimated seepage reduction- higher-permeability sealant in sheet pile wall joints

Higher-permeability sand zone

Lower-permeability sand zone

Combined reduction (based on sand zone assumptions)

Overall System Estimated

Reduction (based on assumptions)

Completely Keyed into Rock 87.79% 46.21% 58.68%

47.3% 1-foot gap below wall 52.87% 34.37% 39.92% 2-foot gap below wall 45.25% 30.86% 35.18% 5-foot weathered shale layer below wall 87.67% 45.89% 58.43%

Table 8: Estimated seepage reduction- lower-permeability sealant in sheet pile wall joints

Higher-permeability sand zone

Lower-permeability sand zone

Combined reduction (based on sand zone assumptions)

Overall System Estimated

Reduction (based on assumptions)

Completely Keyed into Rock 99.96% 99.73% 99.80%

77.9% 1-foot gap below wall 57.05% 59.35% 58.66% 2-foot gap below wall 48.54% 51.28% 50.46% 5-foot weathered shale layer below wall 99.77% 98.27% 98.72%

Accounting for the estimated seepage reduction and accounting for a safety factor of 2, the flow value into the excavation recommended for design is shown in Table 9.

Table 9: Seepage into excavation with sheet pile wall (values for design) Sheet pile wall joint condition used Estimated flow through/beneath wall (gpm)

No sealant in joints 73 Higher-permeability sealant in joints 62

Lower-permeability sealant in joints 26

3.8. Discussion of model results

The higher-permeability sealant only showed a 10 percent greater reduction than no sealant at all while the lower-permeability sealant offered approximately a 30 percent greater reduction in seepage than the higher-permeability sealant.

The presence of gaps below the wall have the potential to significantly reduce the effectiveness of the system. In the models with the lower-permeability sealant, gaps reduced the effectiveness of the cutoff by roughly half.

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Looking at Table 6 through Table 8, it appears that the wall is less effective in cutting off seepage in the lower-permeability sand zone compared to the higher-permeability sand zone. However, the seepage quantities are much lower overall in the lower-permeability sand zone meaning that the difference in reduction in actual flow is not as significant.

Based on the findings, the lower-permeability sealant is recommended for this project as it offers the potential for significantly greater seepage reduction than other measures that were modeled.

Additionally, quality control of the processes used for sheet pile wall installation will be essential. The presence of gaps below the wall or defects within the installation can significantly increase seepage into the excavation.

3.8.1. Potential Impacts of weathered/karstic limestone

According to the geologic mapping provided by the LRL in the area of the sheet pile wall, the Beech Creek Limestone is present from approximately elevation 415 to 400. This limestone is known to be karstic and has the potential to convey a significant amount of flow. The excavation subgrade is at approximately elevation 429, which is well above the Beech Creek Limestone; therefore, it is unlikely that flow from the limestone will enter the excavation. The sheet pile wall keys into rock which is near where the bottom of the limestone. Based on boring ADC 1810, the sheetpiling is anticipated to key into shale below the limestone layer but it is possible that highly weathered limestone may be present. If the sheet pile wall does not penetrate through a weathered/karstic limestone layer, a permeable gap would exist below the wall. This potential was accounted for in the ‘gap’ and ‘weathered rock’ scenarios modeled.

4. Downstream Stilling Basin Excavation Dewatering System Design Along with construction of the SSP wall (dewatering by exclusion), two additional dewatering systems are recommended for the downstream stilling basin excavation. Dewatering wellpoints should be used to draw the groundwater level down initially to allow for safe excavation of soil. Once the groundwater is drawn down and the sheet pile wall is demonstrated to be effectively reducing seepage, a sump/pump system is the recommended method to remove any water entering the excavation from through seepage, precipitation, or other sources. Even if the sheet pile wall and sumps are effective in maintaining a safe groundwater level, the wellpoint system should remain in-place in case that conditions changes.

Conditions that may require the reactivation of the dewatering system include but are not limited to the following.

• Reduction in the effectiveness of the sheet pile wall to cut off seepage into the excavation

• Failure of sump/pumping system

• Excessive groundwater flow into excavation area from other sources (e.g. the karstic limestone)

It is possible that the dewatering wellpoints may have to remain functional for the duration of construction should any of these, or any other conditions, exist or persist to the point that safe groundwater levels cannot be maintained without the wellpoints.

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4.1. Dewatering wellpoints

Based on geologic data in the area of the proposed new downstream stilling basin, it is nearly certain that excavations in this area will intercept some saturated granular material (typically sands with some clay and/or silt). Sandy soils can “flow” or “run” during excavation if the pore water pressure exceeds the soil’s shear resistance, which is easier as the clay content decreases. Excavations in these types of soils are best achieved when dewatered. For instance, even if the walls were supported with a trench box or other support, the exposed base or bottom of the excavation may still become unstable (i.e. heave, flow, loose strength) if not properly dewatered. Even if the sand layer is not intercepted and the base of the excavation is in clay, there are potential concerns when the sand layer is near the surface. Water pressures in the lower unexposed sand stratum may cause the remaining unexcavated clay to heave or uplift, resulting in an unstable excavation. Partial dewatering (or depressurization) of the sand layer would prevent this condition.

Wellpoints, used since the 1920s, are a system of closely spaced (2 to 12 feet apart), small-diameter (~ 1.5 to 2 inches) wells connected to a common header line and vacuum pump. Water is drawn into the wells by suction and conveyed to the pump by the header line. Wellpoints are an acceptable dewatering measure at the downstream stilling basing excavation because the aquifer is relatively shallow (approximately 10 feet below ground surface at ADC-1810) and the drawdown is less than 20 feet (assumed maximum groundwater elevation of 453.5 and lowest point of phase 1 excavation at elevation 437). See Figure 9 for a typical wellpoint diagram.

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Figure 9: Typical wellpoint detail (all details may not apply to this contract)

Design Methodology Calculations used to determine the parameters of the dewatering system were based on a simplified model of the scenario and the methods described in TM 5-815-5 and Foundation Engineering by Leonards.

Particularly this method follows the example found in Figure D-6 of TM 5-818-5. This design process is described in the following steps:

1. Select dimensions and groundwater parameters (aquifer thickness, radius of influence, hydraulic conductivity, etc.) of the formation to be dewatered based on available data.

2. Determine the level of drawdown required.

3. Calculate the required pumping rate (per linear foot) to achieve the required drawdown.

4. Compute the flow per wellpoint at various spacings.

5. Calculate the head loss due to convergence and friction for the wellpoints at the specified spacings (TM 5-818-5 Fig. 4-25).

6. Determine if the wellpoint spacing design is adequate based on available pump vacuum.

7. Select the optimal wellpoint spacing.

8. Use the calculated flow per wellpoint to calculate friction losses and select appropriately sized pump, pipes, and other materials.

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Assumptions The proposed wellpoint system will be placed on the excavation side of the sheet pile wall from SSP wall station 0+80 to 7+50. This is the area where the aquifer thickness is estimated to be greater than or equal to 10 feet. Beyond this zone on the legs of the wall alignment, the aquifer layer is either anticipated as too thin or the wellpoint tip would have to be at too high of an elevation (due to the rising rock elevations) to be effective. The wellpoint line should be placed as close to the edge of the excavation as practical in order to maximize the drawdown. See Figure 10 for approximate limits of the proposed wellpoint system.

Figure 10: Proposed extents of wellpoint system

The wellpoint alignment was split into 3 segments for flow calculations of the wellpoint dewatering system. Segment 1 runs from sheet pile wall Sta 0+80 to Sta 2+20, Segment 2 runs from Sta. 2+20 to Sta 6+20 and Segment 3 runs from Sta 6+20 to 7+20. These segments correspond to the areas designated as Zones 2 and 3 in Figure 4.

The tailwater from the exiting outlet channel (modeled as a “line source”) was assumed to be the only source of water that the sheet pile was defending against and two conditions were modeled. One with the initial groundwater level was set at 453.5, representing a condition with water at the top of the sheet pile wall (worst-case scenario), and the other with the initial groundwater elevation set at 448 (the estimated

F-20 groundwater elevation in the area based on boring logs). Overall, the analysis is conservative given that the sheet pile wall will be installed prior to the operation of the dewatering system. If the wall performs as designed, it will cut off a majority of groundwater flow from the existing outlet channel area.

The groundwater is likely precipitation driven and it is expected that some additional flow will come from the opposite side of the excavation, primarily along the soil/rock interface and the karstic Beech Creek limestone layer. Since there is very limited information on which to estimate the groundwater inflow on the side of the excavation opposite the sheet pile wall, a safety factor of 1.25 was applied. Like sheet pile wall flow-through calculations, the dewatering system is highly sensitive to hydraulic conductivities. As such, calculations were completed for both the high and low estimates of the sandy layer’s hydraulic conductivity. A run was also completed based on the assumptions on the hydraulic conductivity in Table

4. Calculations are summarized in Table 10 and Table 11.

Table 10: Estimated wellpoint flows (initial groundwater at 448 feet)

Sand Zone Properties Calculated Flow per Wellpoint (gpm) System Total

Flow Segment 1 Segment 2 Segment 3 Low Permeability Sand Zone

(k=1.4 x 10-5 ft/s) 0.18 0.32 0.22 16.18

High Permeability Sand Zone (k=1.4 x 10-4 ft/s) 1.80 3.19 2.21 161.81

Sand Zone with assumed properties (k=5.18 x 10-5 ft/s) 0.66 1.18 0.82 59.87

Table 11: Estimated wellpoint flows (initial groundwater at 453.5 feet)

Sand Zone Properties Calculated Flow per Wellpoint (gpm) System Total

Flow Segment 1 Segment 2 Segment 3 Low Permeability Sand Zone

(k=1.4 x 10-5 ft/s) 0.26 0.45 0.31 23.03

High Permeability Sand Zone (k=1.4 x 10-4 ft/s) 2.56 4.53 3.14 230.27

Sand Zone with assumed properties (k=5.18 x 10-5 ft/s) 0.95 1.68 1.16 85.20

Calculations indicate that the wellpoint line could expect between 16 and 230 gpm. This means that the maximum design flow, accounting for the 1.25 factor of safety, is approximately 300 gpm. The most likely design flow is around 100 gpm. This is well within the typical operating range of a 6-inch dewatering pump which can successfully accommodate dewatering flows over 400 gpm.

The recommended diameter of wellpoints is based primarily on the expected flow per wellpoint. Per Powers Table 19.1, 1.5-inch wellpoints can accommodate flows up to 20 gpm without exceeding 3 feet of friction loss. 2-inch wellpoints can accommodate up to 30 gpm without friction losses exceeding 3 feet.

Based on these parameters, and the expected flowrates from this system, 1.5-inch or 2-inch wellpoints could be used. A potential benefit of using 2-inch wellpoints is that they would allow the system to be

F-21 modified to an eductor-type system if required without re-drilling the wells. 1.5-inch wellpoints are too small for conversion to eductors.

Wellpoint spacing is recommended at the maximum of 12 feet. This minimizes the cost, especially since the actual flows into the system will be less than modeled if the sheet pile wall is correctly installed and is functioning as intended. Should the drawdown be insufficient along a portion of the wellpoint alignment, additional wells can be installed in the trouble areas.

4.2. Seepage Collection System/Sumps

It is assumed that a contractor-designed sump dewatering/control system will be used to collect and convey water that enters excavated areas throughout most of the site. An additional seepage collection and sump system will be required to capture any flow that passes through or beneath the sheet pile wall and enters the excavated area. Proper design and installation of this system will allow for the wellpoint system, which is costly to operate, to be shut down. While the final design of this system will also be the responsibility of the contractor, a preliminary design was investigated as a basis for what the system may look like and for cost estimates.

The system will use a combination of a dewatering trench and sumps to collect and remove any seepage.

A trench will be dug along the edge of the excavation facing the sheet pile wall and backfilled with a geotextile wrapped gravel drain. The drain will follow the slope of the tunnel access excavation. Sumps will be placed along the trench such that the incoming seepage does not exceed the trench capacity. A submersible pump will be installed in each sump to remove the water to the discharge point or combine it with the main sump system for the tunnel and excavation.

As calculated earlier, the estimated flow through/beneath the sheet pile wall is approximately 62 gpm with the higher-permeability sealant and 26 gpm with the lower-permeability sealant. Although these sumps are designed to capture flow through/beneath the sheet pile wall, there is potential that seepage from other sources could enter the system as well. It is also possible that the sheet pile wall may not perform as well as anticipated because the sealant was damaged during installation or degraded over time or couldn’t be seated as well as anticipated. Therefore, the volume was increased by 25 percent to size the seepage collection system and sumps.

Trench capacity was calculated with Darcy’s Law (Q=kiA) where Q=flow, k=hydraulic conductivity of soil, and A is the area. The maximum capacity for a given trench was calculated from Darcy’s Law and then divided by the expected flowrate into the trench to determine the necessary sump spacing.

The slope of the tunnel access ramp is 0.50% (i=0.50 ft./100 ft.). The estimated hydraulic conductivity of the gravel drain is 0.3 ft./s. Required sump spacing for each sealant type and several drain dimensions is summarized in Table 12.

Table 12: Minimum required sump spacing for various drain dimensions

Minimum Required Sump Spacing Drain Dimensions

4’ width, 2’ depth 5’ width, 3’ depth

Higher-permeability sealant 34.7 ft. 65.2 ft

Lower-permeability sealant 82.9 ft. 155.4 ft.

F-22

The face of the excavation in the direction of the sheet pile wall is approximately 500 feet long. With the lower-permeability sealant and the larger collection trench (5’ x 3’) calculations show that at maximum flow, just over 3 sumps will be required; therefore, 4 sumps are recommended to ensure adequate capacity. Using the higher-permeability sealant or smaller trench requires more sumps. See Figure 11 for the proposed sump layout. Full calculations are included in the attached appendix.

Figure 11: Proposed sump layout

4.3. Monitoring of Groundwater Levels

A set of piezometers surrounding the excavation and screened in the soil just above the top of rock is necessary to continuously monitor groundwater conditions and determine the effectiveness of the sheet pile wall. Given that the excavation will be open for a long period of time, automated instruments, with periodic manual readings to ensure accuracy, are recommended. Automated data can also quickly be evaluated for trends that would require mitigating actions. See Figure 10 for a proposed layout of piezometers at the stilling basin excavation.

F-23

Key borings for models (Borings used for the development of seepage model cross‐sections)

F-24

466.5

464.1

463.1

The time interval for each core run is shown in military time (e.g, 1423-1446) in the remarks column.

Auger Refusal at 4.8'. 6 inch PVC casing installed to 5.3 feet and annulus grouted prior to coring (7 gallons).

Began core at 4.5' Box #1 4.5' to 11.2' From 4.5'-4.9' grout from casing installation

1028 - 1034 2/21/2019

1042 - 1055

Near horizontal fractures at: 8.7', 8.8', 9.7', 10.2', 10.35', 11.2', and 11.8'

Box #2:

11.2' to 18.3'

Iron staining along most fractures

1245 - 1252

Near horizontal fractures at 13.1', 13.5', 13.6', 14.7', 15.6', and 16.5'

15 degree fracture along bedding plane/clay filled from 16.3'-16.5'

1315 - 1320

Box #3:

18.3' to 24.0'

Near horizontal fractures at 18.25', 19.0', and 21.0'

12 to 15 degree fracture at 19.6'

2.8

4.9

2.7

ROCK

ROCK

ROCK

TOPSOIL, dark brown to brown, moist with organics and roots

LEAN CLAY, with silt, brown, damp, with some sand

SANDSTONE (Big Clifty Sandstone), light brown with gray, very fine grained, weathered (augered)

SANDSTONE (Big Clifty Sandstone), brown-gray, fine to medium grained, zones of shale, irregularly bedded, moderate to highly weathered, medium hard, some zones weakly cemented

- Highly weathered rock, soft zone from 5.1' to 5.5'

- Clay parting at 6.2', with fractures around it

- Clay-Shale from 7.4' to 7.6', highly weathered, soft

- Clay partings from: 9.7' to 9.8', and 11.3' to 11.6' (highly weathered)

- Occasional clay nodules

- Clay-Shale layers from: 13.1' to 13.3' (40' fracture/joint at 13.3', clay filled), 13.6', 13.9' to 14.0', and 15.6' to 15.7'

- At 15.0', partially healed fracture along clay filled lens

- From 18.2' to 18.6' multiple Clay-Shale layers

- Clay-Shale layers from: 19.05' to 19.45', 20.0' to 20.1', and 20.8' to 20.9'

TOPSOIL, dark brown to brown, moist with organics and roots

LEAN CLAY, with silt, brown, damp, with some sand

SANDSTONE (Big Clifty Sandstone), light brown with gray, very fine grained, weathered (augered)

SANDSTONE (Big Clifty Sandstone), brown-gray, fine to medium grained, zones of shale, irregularly bedded, moderate to highly weathered, medium hard, some zones weakly cemented

- Highly weathered rock, soft zone from 5.1' to 5.5'

- Clay parting at 6.2', with fractures around it

- Clay-Shale from 7.4' to 7.6', highly weathered, soft

- Clay partings from: 9.7' to 9.8', and 11.3' to 11.6' (highly weathered)

- Occasional clay nodules

- Clay-Shale layers from: 13.1' to 13.3' (40' fracture/joint at 13.3', clay filled), 13.6', 13.9' to 14.0', and 15.6' to 15.7'

- At 15.0', partially healed fracture along clay filled lens

- From 18.2' to 18.6' multiple Clay-Shale layers

- Clay-Shale layers from: 19.05' to 19.45', 20.0' to 20.1', and 20.8' to 20.9'

BORING NO.

VERTICAL INCLINED

9. DIRECTION OF BORING

5. DRILL TYPE

6. THICKNESS OF OVERBURDEN

7. DEPTH DRILLED INTO ROCK

8. TOTAL DEPTH OF BORING

3. DRILLING AGENCY

4. NAME OF DRILLER

2. LOCATION

1. PROJECT

CME 45T (815)

Kent Clements

3.9'

63.7'

67.6'

SHEET 1ADC-1809 OF 5

10. DATUM FOR ELEVATION

SHOWN ITEM (TBM OR MSL)

11. DRILL METHOD

12. ELEVATION TOP OF HOLE

13. TOTAL NUMBER CORE BOXES

14. ELEVATION GROUND WATER

COMPLETED

2/25/19

STARTED

15. DATE HOLE

16. INSPECTOR

Daniel Rogers/ Luis Arduz

468.0'

1/9/19

Stantec

N/A

Rough River Dam Outlet Works PH 1

N: 2109871 E: 1422426.8

4.25" HSA and PQ3-wire line

MSL

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CLASSIFICATION

OF MATERIALS

HOLE NO.

ADC-1809

PROJECT: Rough River Dam Outlet Works PH 1LRL FORM 1202

JUNE 2000

PREVIOUS EDITIONS ARE OBSOLETE.

SYMBOLS: WATER LEVELS AT COMPLETION PARTIAL LOSS OF DRILL FLUID

F-25

432.9

429.1

From 21.1' to 21.4', partially healed fracture, weathered and water stained

YM: 2,920,000 psi

PR: 0.44

Box #4:

24.0' to 29.8' STS: 372 psi 1330 - 1346

Near horizontal fractures at 24.0', 25.2', 26.5', and 27.0'

1407 - 1414

Box #5:

29.8' to 36.8'

Near horizontal fractures at 28.3', 28.9', 29.8', 30.65', and 32.25'

Near horizontal fractures at 32.7', 33.3', 33.85', 34.1', 34.5', and 35.0'

1431 - 1442

Box #6:

36.8' to 42.6'

Near horizontal fractures along bedding planes at 37.25' and 37.4'

DS-NF test performed at 38.2' DS-SS test performed at 38.3' 1453 - 1542

Sandstone lense at 39.0', 39.3', and 39.8'

Highly weathered, very soft from 39.5' to 39.7'

Near horizontal fractures at 38.2', 38.65', 38.9', 39.3', and 41.15'

Multiple mechanical/drilling fractures from 39.8' to 42.6'

1604 - 1701

ROCK

ROCK

ROCK

ROCK

ROCK

SANDSTONE (Big Clifty Sandstone), brown-gray, fine to medium grained, zones of shale, irregularly bedded, moderate to highly weathered, medium hard, some zones weakly cemented (continued)

- Heavily water staiend, weathered rock from 23.5' to 27.0'

- Water stained from 27.6' to 28.9'

- Clay-Shale partings at: 28.9' to 29.1', 29.8' (less than 0.1')

- Water stained from 32.6' to 35.1'

SANDSTONE (Big Clifty Sandstone) and shale interbedded, light gray to dark gray, irregular/turbulent bedding, medium hard

- Clay-Shale layer, highly weathered and fractured from 36.7' to 36.8'

SHALE (Big Clifty Shale), medium to dark olive gray, thin bedded (laminated), occasional limestone partings and nodules, soft, moderately weathered with highly weathered zones

SANDSTONE (Big Clifty Sandstone), brown-gray, fine to medium grained, zones of shale, irregularly bedded, moderate to highly weathered, medium hard, some zones weakly cemented (continued)

- Heavily water staiend, weathered rock from 23.5' to 27.0'

- Water stained from 27.6' to 28.9'

- Clay-Shale partings at: 28.9' to 29.1', 29.8' (less than 0.1')

- Water stained from 32.6' to 35.1'

SANDSTONE (Big Clifty Sandstone) and shale interbedded, light gray to dark gray, irregular/turbulent bedding, medium hard

- Clay-Shale layer, highly weathered and fractured from 36.7' to 36.8'

SHALE (Big Clifty Shale), medium to dark olive gray, thin bedded (laminated), occasional limestone partings and nodules, soft, moderately weathered with highly weathered zones

1. PROJECT Rough River Dam Outlet Works PH 1

BORING LOG (cont sheet) ELEVATION TOP OF HOLE 468 Hole No. ADC-1809

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CLASSIFICATION

OF MATERIALS

HOLE NO.

ADC-1809

PROJECT: Rough River Dam Outlet Works PH 1LRL FORM 1202

JUNE 2000

PREVIOUS EDITIONS ARE OBSOLETE.

SYMBOLS: WATER LEVELS AT COMPLETION PARTIAL LOSS OF DRILL FLUID

F-26

412.7

402.4

400.4

Box #7:

42.6' to 47.6'

Near horizontal fractures at 44.4', 46.0', 47.0', 47.4', 48.2', and 48.75'

0725 - 0807 2/25/2019

Box #8:

47.6' to 52.6'

Mechanical breaks along bedding planes at 49.7', 51.25', and 51.95'

Box #9:

52.6' to 59.0'

From 53.6' to 54.4' near vertical fracture

Fractured, slightly weathered from 54.5' to 55.1'

1015 - 1048

YM: 8,410,000 psi

PR: 0.33

STS: 1114 psi

Box #10:

59.0'-65.6' DS-NF test performed at 58.2'

From 58.95' to 59.0' possible solution feature, weathered and fractured

1113 - 1131

YM: 2,860,000 psi

PR: 0.32

YM: 9,990,000 psi

PR: 0.38

Styolitic fracture at 62.3'

Fracture partially solutioned from 63.15' to 63.2'

Near horizontal fracture at 63.5'

1150 - 1216

Box #11:

65.6' to 67.6'

YM: 260,000 psi

PR: 0.39

Joint at 65.6' Zones fractured from 65.6' to 66.8'

Geophysical survey performed by ARM Geophysics on 3/12/19.

Pressure Test Results

ROCK

ROCK

ROCK

ROCK

ROCK

SHALE (Big Clifty Shale), medium to dark olive gray, thin bedded (laminated), occasional limestone partings and nodules, soft, moderately weathered with highly weathered zones (continued)

- Limestone layers at: 47.9' to 48.0', 48.25' to 48.85'

- Limestone layer from 54.4' to 54.5'

- Occasional pyrite inclusions

- Clay-Shale layer from 55.1' to 55.3', highly weathered, soft

LIMESTONE (Beech Creek Limestone), light gray, fine to medium crystalline grained, fossiliferous (highly fossiliferous between 55.3' and 56.5'), with occasional shale stringers and streaks, hard

- Rippled/wavy bedding from 56.9' to 67.6'

- Styolites at 58.2', from 62.0' to 62.6', and from 62.6' to 63.9'

SHALE (Elwren Shale), medium to dark olive gray, clayey to sandy, thinly bedded (laminated), moderately weathered, soft to medium hard

End of boring at elevation 400.4 feet.

SHALE (Big Clifty Shale), medium to dark olive gray, thin bedded (laminated), occasional limestone partings and nodules, soft, moderately weathered with highly weathered zones (continued)

- Limestone layers at: 47.9' to 48.0', 48.25' to 48.85'

- Limestone layer from 54.4' to 54.5'

- Occasional pyrite inclusions

- Clay-Shale layer from 55.1' to 55.3', highly weathered, soft

LIMESTONE (Beech Creek Limestone), light gray, fine to medium crystalline grained, fossiliferous (highly fossiliferous between 55.3' and 56.5'), with occasional shale stringers and streaks, hard

- Rippled/wavy bedding from 56.9' to 67.6'

- Styolites at 58.2', from 62.0' to 62.6', and from 62.6' to 63.9'

SHALE (Elwren Shale), medium to dark olive gray, clayey to sandy, thinly bedded (laminated), moderately weathered, soft to medium hard

1. PROJECT Rough River Dam Outlet Works PH 1

BORING LOG (cont sheet) ELEVATION TOP OF HOLE 468 Hole No. ADC-1809

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CLASSIFICATION

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HOLE NO.

ADC-1809

PROJECT: Rough River Dam Outlet Works PH 1LRL FORM 1202

JUNE 2000

PREVIOUS EDITIONS ARE OBSOLETE.

SYMBOLS: WATER LEVELS AT COMPLETION PARTIAL LOSS OF DRILL FLUID

F-27

Rock core boring was tremie filled with

99.6 gal of cement-bentonite grout.

Surface casing was grouted in place and a concrete plug was placed at the surface.

Test Legend

DS-NF: Direct Shear (Natural Fracture) Peak Shear Stress DS-SS: Direct Shear (Sawn Surface) Peak Shear Stress YM: Young's Modulus PR: Poisson's Ratio PO: Pull-Out Test Maximum Stress SDI: Slake Durability Index STS: Splitting Tensile Strength CAI: CERCHAR Abrasiveness Index

Bottom of hole at 67.6 feet.

Top Depth Bottom Depth Test Pressure Pressure Drop Total Water*

(ft) (ft) (psi) (psi / 60 seconds) (GPM)

7.6 12.6 4 0.5 --

12.6 17.6 6 3.0 --

17.6 22.6 9 4.0 --

22.6 27.6 11 2.0 --

27.6 32.6 14 2.0 --

32.6 37.6 16 2.0 --

37.6 42.6 19 4.0 --

42.6 47.6 21 1.5 --

47.6 52.6 24 Continuous flow 1.32 observed

52.6 57.6 24 5.0 --

57.6 62.6 29 6.0 --

62.6 67.6 31 1.0 --

*Flow test duration was 5 minutes.

1. PROJECT Rough River Dam Outlet Works PH 1

BORING LOG (cont sheet) ELEVATION TOP OF HOLE 468 Hole No. ADC-1809

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CLASSIFICATION

OF MATERIALS

HOLE NO.

ADC-1809

PROJECT: Rough River Dam Outlet Works PH 1LRL FORM 1202

JUNE 2000

PREVIOUS EDITIONS ARE OBSOLETE.

SYMBOLS: WATER LEVELS AT COMPLETION PARTIAL LOSS OF DRILL FLUID

F-28

KEY TO SYMBOLS

Strata symbols

Symbol Description

Notes:

Topsoil

USCS Lean Clay

Sandstone

Shale

Limestone

KEY TO SYMBOLS

Strata symbols

Symbol Description

Notes:

1. Exploratory boring was drilled on 1/9/2019 using a CME 45T (815).

2. Water was encountered at feet.

3. These logs are subject to the limitations, conclusions, and recommendations in this report.

4. Results of tests conducted on samples recovered are reported on the logs.

Sampler symbols

HOLE NO.

ADC-1809

PROJECT: Rough River Dam Outlet Works PH 1LRL FORM 1202

JUNE 2000

PREVIOUS EDITIONS ARE OBSOLETE.

SYMBOLS: WATER LEVELS AT COMPLETION PARTIAL LOSS OF DRILL FLUID

F-29

440.5

436.2

433.7

1.3

1.5

0.8

1.5

0.7

1.5

1.2

1.5

0.9

1.5

1.5

1.5

Wet Below 2.8 feet

Blue Wire Recovered from 8.9' to 9.0'

Zone of Clay from 17.9' to 18.5'

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

1.5

SILTY CLAY, Brown, Moist to Wet, Fine Grained, Trace of Some Sand, Stiff to Soft, Trace of Mica

Moderate Dilatency

Light Brown and Increased Sand from 4.0' to 5.5'

Roots/Organics at 8.7' to 9.0'

CLAYEY SILTY SAND, with Gravel, Brown to Gray, Wet, Loose, Gravel in Sandstone Angular 3/4" to 1.0"

SAND with Trace of Silt, Light Tan, Wet, Loose, Very Fine Grained

CLAYEY SILTY SAND, Brown with Mottled Gray, Wet, Very Loose, Fine Grained

SILTY CLAY, Brown, Moist to Wet, Fine Grained, Trace of Some Sand, Stiff to Soft, Trace of Mica

Moderate Dilatency

Light Brown and Increased Sand from 4.0' to 5.5'

Roots/Organics at 8.7' to 9.0'

CLAYEY SILTY SAND, with Gravel, Brown to Gray, Wet, Loose, Gravel in Sandstone Angular 3/4" to 1.0"

SAND with Trace of Silt, Light Tan, Wet, Loose, Very Fine Grained

CLAYEY SILTY SAND, Brown with Mottled Gray, Wet, Very Loose, Fine Grained

BORING NO.

VERTICAL INCLINED

9. DIRECTION OF BORING

5. DRILL TYPE

6. THICKNESS OF OVERBURDEN

7. DEPTH DRILLED INTO ROCK

8. TOTAL DEPTH OF BORING

3. DRILLING AGENCY

4. NAME OF DRILLER

2. LOCATION

1. PROJECT

CME 45T (815)

Kent Clements

46.2'

4.7'

50.9'

SHEET 1ADC-1810 OF 4

10. DATUM FOR ELEVATION

SHOWN ITEM (TBM OR MSL)

11. DRILL METHOD

12.…