GDR App D.pdf

Success Dam Spillway Enlargement Project Geotechnical Data Report

APPENDIX D – SEISMIC REFRACTION REPORT

pete.nix Rectangle Success Dam Spillway Enlargement Project

Technical Memorandum

Geophysical Service Center

Technical Memorandum FY19-02

Subject: Seismic Refraction Survey, Success Dam Spillway

By: Lewis Hunter, Sr. Geologist, Ph.D., P.G., Geology Section, Sacramento District

Bethany Burton, Geophysicist, Geology, Geophysics, and Geology Science Center, USGS, Denver, CO

Kyle Lindsay, Geophysicist, Geology Section, Sacramento District

Date: 4 September 2019

Reviewed by:

Verne Brown, Geologist, Geology Section, Sacramento District

Ken Pattermann, Geotechnical Engineer, Dam Safety Section, Sacramento District

Background

Success Lake and Dam is a multi-purpose facility that provides flood damage reduction benefits, irrigation water storage, recreation, and electrical power generation. The dam is located on the Tule River about 5 mi upstream of Porterville, CA. Spanning 3,404 ft across the river, the dam impounds Success Lake and its 390 mi2 watershed. The project spillway is located north of the right abutment of the dam and has a 2.2% annual chance exceedance (ACE) equivalent to approximately the 46-yr flood. Release through the spillway has only occurred once since construction, which was completed in 1961. The Tule River Basin Investigation Final Feasibility Report (1999) recommended that the storage capacity of Success Lake be increased by raising the spillway threshold 10 ft. Authorization for construction is provided by the Water Resources Development Act (WRDA) of 1999 Section 101 (b)(4) (Public Law 106-53, 17 August 1999), which authorized the flood damage reduction and water supply project based on the recommendations of the final report of the Chief of Engineers.

Congressional supplemental funding was appropriated for the project in 2018 with a stipulation of an accelerated schedule. To accommodate this schedule, the US Army Corps of Engineers (USACE) is conducting geotechnical investigations to support the development of a 90% design document by September 2019, road realignment by 2020, and weir/spillway widening finished by 2021. A new 10-ft high concrete ogee weir is planned for the spillway that willincrease storage and flood control capacity from 82.300 acre-ft to 110,300 acre-ft. In the process the spillway will be increased in width from 200 ft to 365 ft.

This report describes a geophysical investigation conducted by the Sacramento District (SPK) in collaboration with the US Geological Survey (USGS). A seismic refraction survey was conducted between 10 – 20 December 2018 and 25 – 26 July 2019 to use P-wave velocity as a proxy for rock hardness and rippability. During this time, data was collected along 14 seismic lines: seven (7) on the existing spillway floor; four (4) along the right abutment and proposed path for road realignment, two (2) located on the upper slope of the right abutment and one (1) line across the ridge on the left abutment (Figure 1).

Methodology

To evaluate rippability a series of seismic refraction lines were acquired to document the vertical P-wave velocity structure in the shallow subsurface. Lines used for the geophysical data acquisition ranged from 366 ft in length to just over 1000 ft (Tables 1 & 2). Data were collected using a Geometrics Geode system with up to 144 active channels (Figure 2) and 40-Hz vertical geophones (e.g., geophones designed to measure vertical motion: P-waves). Geophones were planted at 3- and 6-ft spacing, such that a full 96 geophone array (or spread) spanned 570 ft on the ground surface. The spread layout design considered the desired lateral and vertical resolution, the desired depth of investigation, and the practical energy propagation limit of a sledgehammer and plate source given the site conditions. For lines longer than 570 ft one or more, roll-alongs were required. To conduct a roll-along, a series of geophones and cables were removed from the low-end of the line (geophone numbers increase sequentially from the start of the line;

here the low-end refers to the geophones with the lower number assignment) and transferred to the high end and used to extend lines. Subsurface coverage was also acquired by taking off-end shots at the beginning and end of the spread.

The seismic sources used during the survey included 16-lbs and 20-lbs sledgehammers, and a truck hitch mounted 100-lbs accelerated weight drop (AWD) hammer (Figures 3 & 4). Both sledgehammers were used on Line 5 due to the handle on the 20-lbs hammer breaking in the middle of the line causing a switch to the 16-lbs hammer. Where topography allowed an SUV to be driven up along the line, the 100-lbs AWD source was used. The advantage of the AWD was higher energy input into the ground to improve signal detection at greater distances; however, a cleaner signal was achieved using the sledgehammer sources. On most lines, both the sledgehammer and the AWD sources were used. At the point where sources were alternated, the station was occupied using both sources for comparison of quality and trigger timing. Three (3) to ten (10) hits were recorded and stacked to produce an stacked shot record at each shot location. Data was monitored by a USGS geophysicist performing real-time quality control.

Stacking improves the signal to noise ratio and can be monitored on screen by evaluating the signal improvement with each successive hammer strike (Figure 5). When signal improvement was negligible, data collection stopped and the team moved on to the next station. Typically, the shots at the far ends of the lines required 10 hits to try to get energy to the distant geophones while the shots in the center of the line were generally reduced to three hammer hits per shot station.

Data were processed using the software Rayfract by Intelligent Resources Inc. Data processing consisted of importing raw SEG2 field records, geometry assignment, and application of automatic gain control.

First-break picks were then manually picked by the data processor for each line. Travel-time curves were generated during the picking allowing the processor to evaluate the picking in real time. Once the first-break picking was complete, the software is used to perform a finite-element inversion to generate a 2-dimensional profile representing the velocity structure in the shallow subsurface. Note that these models are smoothed approximations of the true velocity where true variations in velocity may have sharp contrasts and detailed features that cannot be resolved. However, the tight geophone spacing and relatively tight shot spacing provides considerably more detail than traditional refraction surveys where shots are taken at the beginning, middle, and end of the line.

Quality Control

Three (3) phases of quality control (QC) were applied to the field data: field, processing, and visual evaluation of results.

Field QC consisted of an experienced operator controlling field data collection. The operator from the USGS had more than 15-years’ experience collecting seismic data. Her role included visually screening each shot record as it came in as well as monitoring background noise. When background noise was observed in the data (caused by vehicle traffic, airplanes, wind, or someone walking in close proximity to the line) collection was paused until it was no longer present in the record. On 26 July during the collection of Line 15, it became so windy that a satisfactorily clean record could not be collected. This was compounded by air temperatures over 104 ° F that impacted the field crew’s ability to safely collect data. As a result, the initial data collection never got past testing the geophones and cables for proper function and arrangement and was paused until 6 PM that evening when the wind had ceased and temperature had dropped.

Data processing was conducted by four individuals. Three (Dr. Hunter, Mr Kyle Lindsay and a USGS intern) performed the initial first break picks. Both constantly monitored the travel-time curve as the data was processed to make sure velocities didn’t take any unreasonable jumps. Following the initial picking, Beth Burton (USGS Geophysicist) reviewed each line and modified picks to ensure pick consistency and accuracy and to remove any timing related issues in these data.

The final phase of QC was performed using the software LeapFrog Works. Here the 2-D inversion profiles were imported into the software and plotted in a three-dimensional environment. The initial phase was to match profile topography to the digital elevation model generated from the latest LiDAR data projected in NAVD 88. Once hung, the elevation grid was compared against the elevation projected in the model and data was manually adjusted until the grid lines were within 6-in of the projected elevation. At this point, profile intersections were visually evaluated to look for apparent mismatches. This evaluation resulted in lines 3, 4 and 8 being re-evaluated to assess consistency of picks and to improve the fit at intersections.

Results

The inverted velocity models output from Rayfract are presented in Appendix A. The travel-time curves used to evaluate coverage and used as a quality control tool during the picking process are shown in Appendix B. The final profiles with boreholes superimposed are presented in Plates 1 – 8 and the survey parameters are summarized in Table 1. All elevations presented are in NAVD88. Note: this letter report is intended to document the field data collection and processing results so that these data can be shared with team members in the design of the spillway modification and weir design. As such, minimum interpretation is provided. In general terms the description below focuses on the velocity profiles with low velocity zones having an interval P-wave velocity (Vp) below 3,000 feet per second (fps1) and high-velocity zones being above 10,000 fps. This roughly corresponds to poor-quality rock and rock weathering products being represented by the low-velocity zones with improved weathering conditions (e.g., better quality rock) as velocity increases. Some caveats to this are:

• Boring logs superimposed onto seismic sections are for general reference and correlation for the user (no interpretation is implied).

• Lithology presented in the boring logs represent weathering grade.

• Field loggers at Success Dam report that weathering is strongly controlled by lithologic variability, which is complex at the site.

• Weathering grade is also influenced by fracture/joint occurrence that provides pathways for meteoric water to infiltrate and cause localized weathering.

1 3000 fps and 10,000 fps velocities are arbitrary values used for describing relative changes in the velocity structure. No detailed analysis has been conducted on the Success Dam data to correlate velocity to weathering grade or rock type. Use of these values is intended only to describe relative differences where rock quality increases with higher velocity values.

• Rippability assessment in the granodiorites at Isabella Dam yielded refusal for a D-10 Caterpillar with single tooth at velocities between 4,500 – 5,500 fps (Vp) instead of the 7275 fps value published in Caterpillars tables (Hunter 2014).

Spillway Invert

Line 1

Line 1 was collected on December 10 and 14 as two (2) individual spreads and then merged during processing. The line was oriented roughly west-southwest to east-northeast with its full extent north of the spillway center line (Figure 1). Pavement covered the ground surface from approximately line stations 45 ft to 105 ft and the existing weir was encountered between line stations 180 to 186 ft. Shallow fill over bedrock occurred from approximately line stations 105 ft to 380 ft. The west half of the line is characterized by a thin (<10 ft) slow zone (Vp < 3000 fps; Plate 1a). Velocity in excess of 6,000 – 8,000 fps at depths ranging from 0 – 15 ft between line stations 75 – 120 ft. These transitions begin to dip eastward and deeper into the subsurface starting around line station 375 ft, reaching maximum depths around line station 750 – 800 ft. At 800 ft, the transition between 3,000 – 4,000 fps occurs at about elevation 610 ft (about 40 ft below ground surface [bgs]). The transition to 9,000 – 10,000 fps occurs between 560 – 570 ft elevation (or about 80 ft bgs). The transition zone with velocity between 5,000 – 8,000 fps reaches a thickness of about 30 ft between line stations 500 to 775 ft.

Line 2

Originally proposed to extend down center of spillway between Lines 1 and 3. This line was removed when Lines 12 and 13 were requested by project team. Lines 1 and 3 were each re-aligned towards the center of the channel to accommodate deletion of Line 2 to provide similar desired coverage.

Line 3

Line 3 was collected on 11 December 2018 and is situated along the southern margin of the upper spillway (Figure 1). The line was oriented roughly west-southwest to east-northeast and crossed the spillway center line at station 11+10 near line station 160 ft. Pavement near the start of Line 3 occurred between line stations 33 ft and 63 ft. Bedrock was observed at the ground surface from line station 93 ft to approximately line station 201 ft. The existing weir was encountered between line stations 261 ft to 273

ft. Shallow fill over bedrock occurred from approximately line stations 275 ft to 540 ft. As with Line 1, relatively high velocity is encountered in the very shallow subsurface in the western half of the line (Plate 1b). Velocities in excess of 5,000 – 6,000 fps occur at or near the subsurface (< 10 ft), with a zone between 100 – 175 ft along the line where Vp is in excess of 10,000 fps at the ground surface. A very thin (~5 ft) zone between line stations 275 – 400 ft has a velocity below 4,000 fps. From the start of the line to about line station 525 ft, velocities of 10,000 fps are encountered shallower than 20 ft bgs. This high velocity zone thickens and dip to the east starting at about 550 ft distance. East of 550 ft the transition to faster velocities dips. By 900 ft along the line a velocity of 5000 fps in not encountered until approximately 50 ft bgs (elevation 600 ft), and 10,000 fps is not encountered until 80 ft bgs (about elevation 570 ft).

Table 2. Geophysical line coordinates

Projection: California State Plane, Zone 4 ft; NAVD88

Line 4

Line 4 was collected on 12 December 2018 and cuts across the spillway in a NW-SE orientation (Figure 1). Its overall length was 570 ft (Table 1) and crosses the spillway center line at station 6+20 and about line station 160 ft. Pavement associated with the access road occurred between line stations 33 ft and 60

ft. All sections east of the road have fill and/or decomposed granite at the ground surface. The upper 25 to 30 ft exhibit a velocity generally below 4,000 fps with small zones of slightly faster velocities nearing the surface around line stations 75 ft, 150 – 180 ft, and 280 – 310 ft indicating a slightly hummocky variation in the velocity profile (Plate 2a). Velocities exceeding 10,000 fps are generally encountered deeper than 70 ft below the ground surface, or roughly 580 ft in elevation, except between 100 – 260 ft along the line where 10,000 ftp comes to within 35 ft of the ground surface at about 615 ft in elevation.

Line 5

Line 5 is 570 ft long and oriented north – south running roughly perpendicular to the access road (Plate 3a). This line was collected on 13 December 2018 (Table 1) and crossed the spillway center line at station 12+50 and line station 620 ft. Pavement associated with the access road occurred between line stations 21 ft and 81 ft. A deep erosional ravine extends from about line station 310 ft and decomposed granite on the west side of the ravine occurs from line station 380 to the end of the line. The line is characterized by a southerly thickening slow velocity zone. Velocities below 4,000 fps are encountered about 80 ft downline and thicken to about 25 ft by line station 350 ft and then roughly maintain that thickness to the end of the line. The first 80 ft of the line exhibit velocities between 5,000 to 6,000 fps.

Velocities of 10,000 fps are reached 20 – 25 ft below the ground surface (~630 ft elevation) for the first

150 ft of the line then steps down to 35 – 40 ft depth to line station 260 ft before it drops to 65 – 70 ft depth (~680 ft elevation) from about line station 360 ft to the end of the line.

Line 6

Line 6 is located in the lower chute of the spillway on the east side of the valley (Figure 1). The line is oriented roughly north to south with its southern extent running along the top of the east side of the erosion ravine in the spillway. A thin layer of decomposed gravel covers the line to about line station 210 ft where moderately to slightly weathered rock is exposed. A compacted gravel road was encountered between line stations 235 ft to 260 ft. Highly-weathered granite was encountered at line stations 273 ft, 333 ft, 345 ft and 447 ft. The line runs along the east side of the ravine from line station 537 ft. The line crosses the spillway center line at station 12+50 about line station 96 ft. The line was collected on 14 December 2018 (Table 1). Plate 3b indicates a hummocky pattern in the velocity profile with pockets of slow velocity rock (<3,000 fps) between line stations 170 – 320 ft, 380 – 450 ft, and 470 to the end of the line (Plate 3a). These pockets range in thickness from 10 ft to 30 ft (~610 – 620 ft elevation). Below this depth, Vp increases rapidly indicating higher quality rock between 620 – 640 ft elevation (or near surface to 40 ft below ground surface).

Line 7

Plate 4 shows the profile for line 7 collected on 20 December 2018 (Table 1). The line was approximately 860 ft long and oriented southwest to northeast. This line cuts diagonally across the spillway at the spillway elbow with the start and end adjacent to the right bank and nearly touching the left wall near the center of the line (line station 360 – 500 ft). As such, the line crossed the spillway center line at stations 8+50 and 14+75 at approximate line stations of 740 ft and 150 ft, respectively. Pavement associated with the access road occurred between line stations 9 ft and 45 ft as well as 849 ft to 867 ft.

Outcrops of decomposed granite occur from line station 117 ft to 141 ft, giving way to moderately- to slightly-weathered granite around line station 153 ft. Decomposed granite then crops out at line station 165 ft and there is a compacted gravel road between line stations 189 ft to 235 ft. A boulder field with rubbly granitic boulders laying on bedrock occurs between line stations 273 ft to 333 ft. Boulder-rubble also occurs around line station 525 ft before the existing weir, which was encountered between line stations 537 ft and 580 ft. For most of the line velocities below 3,000 fps are restricted to the upper 10 ft below the ground surface, except at the ends of the line where the thickness of the slower rock reaches 15 to 20 ft (down to nearly 630 ft elevation). As with Line 6, the transition to fast rock is confined over a narrow zone. Between line stations 150 to 780 ft velocities exceeding 10,000 fps and are achieved between 15 to 20 ft (elevation 630 – 635 ft) below the ground surface. There is a significant change in this profile nearing line station 800 ft where the transition to 10,000 fps drops to nearly 60 ft below ground surface; likely due to structural controls.

Line 8

Line 8 shown on Plate 2b was collected on 12 December 2018 in a southwest – northeast orientation that cut diagonally across the spillway. The seismic line crosses the spillway center line at station 6+70 approximately 155 ft along the line. The access road was encountered between line stations 261 ft and 300 ft, with the remainder of the line being covered by fill and/or decomposed granite. The overall length was 366 ft. The line is characterized by a thin slow zone (< 3,000 fps) that gradually thickens to about 10 ft near the end of the line (line station ~350 ft). The slow zone is intermittent (likely limited by survey resolution) over the first 100 ft of the line. Velocity in the range of 5,000 – 6,000 fps occurs in the shallow subsurface near the start of the line (along toe of left wall) where it is less than 5 ft thick, then thickens to the northwest reaching thicknesses of 40 to 45 ft (line stations ~170 – 200 ft and 280 – 360 ft).

Overall, the top of high-velocity (>10,000) rock forms an irregular surface. High-velocity rock occurs near the surface (~10 ft below ground) at the start of the line and takes several steps as it thickens to the northeast. After line station 170 ft, the high-velocity zone is encountered at just over 50 ft from the surface, near elevation 600 ft.

Spillway Right Abutment

Line 9

Line 9 is the southern-most line collected on the right abutment. The line was collected from the southwest to the northeast on 16 December 2018 and extended for 714 ft (Plate 5a). The line ran near the crest of the spillway excavation where local relief is about 75 ft along the line transect. The first 213 ft of the line ran along a gravel road. The only rocky outcropping were observed around line station 525 ft.

Soft road shoulder was crossed at line station 549 ft and the gravel road was again crossed between line stations 561 ft to 645 ft. The low velocity zone (<3,000 fps) roughly mimics surface topography ranging in thickness from less than 5 ft to about 25 ft. This thickest portion of the slow velocity zone occurs in the vicinity of the topographic high while the thinnest portion occurs on the steeper slope around line stations 380 – 390 ft. The top of the high velocity (>10,000 fps) rock is uneven ranging in depth from the surface of about 30 to 100 ft, or elevations 600 – 680 ft. The transitional zone (Vp 3,000 – 10,000 fps) ranges in thickness from about 15 ft to 90 ft.

Line 10

Line 10 was collected along the right abutment from the ridge crest and extending across a narrow valley with approximately 150 ft of vertical relief (Figure 1 & Plate 5b). Data was collected on 18 December 2018. No bedrock outcrops were observed during the collection of Line 10. Velocity transitions as shown on the inversion profile roughly mimic the ground surface. A near surface layer (2,000 – 3,500 fps) is generally 20 to 30 ft thick but thickens to more than 40 ft thick east of the valley center. This is underlain by a transitional layer (3,500 – 9,000 fps) that is 40 to 60 ft thick that then transitions to a higher velocity zone (>10,000 fps).

Line 12

Line 12 is located along the northern projection of the road realignment in a generally south – north orientation (Figure 1). This line was collected on 19 December 2018. Thin soil over decomposed granite was observed from the start of the line to about line station 125 ft, but decomposed granite was sporadically observed until about line station 285 ft. The line then crossed a small valley that had been filled to provide road base from about line station 297 ft to 520 ft and a plateau built over fill extends from line station 590 ft to about 880 ft. The profile shown in Plate 6a exhibits a slow zone (<3,500 fps) of variable thickness. The zone is about 10 ft thick from line station 0 to 180 ft, then thickens to about 50 ft between line stations 200 – 275 ft over a transitional zone over nearly the full 50 ft thickness with a velocity between 3,000 – 4,000 fps. Velocities in the 2,000 – 3,000 fps range are 20 to 40 ft thick between line stations 300 to 500 ft (becoming shallower to the north). More transitional values in the range of 3,000 – 4,000 fps occur between line stations 550 to 725 ft extending down a little more than 40 ft (elevation around 630 ft). It should be noted that there is a topographic high, likely mostly fill around 10 ft thick, that extends from line station 600 ft to 880 ft. North of this, the slow zone is about 15 ft thick.

The transition to 5,000 fps occurs around elevation 630 to 650 between line stations 300 ft to 725 ft, with a high at 650 ft between line stations 500 – 525 ft. The thickest transition (~70 ft) between 5,000 – 10,000 fps occurs in the first 150 ft of the line and 530 – 550 ft elevation. Velocities over 10,000 fps (generally assumed to be good crystalline bedrock) dips from elevation 600 ft to 575 ft (80 to 100 ft bgs) in the first 275 ft along the line. There are two “plateau” features: line stations 300 – 475 (600 ft elevation: 60-70 ft bgs) and 800 – 1000 ft (650 ft elevation: ~30 ft bgs from natural ground surface).

Line 13

Line 13 was collected on 17 December 2018 in a southwest to northeast orientation, intersecting Lines 8 and 10 near the start of the line (west end) and projecting towards the southern end of Line 12 (Figure 1).

No bedrock outcrops were observed during the collection of Line 13. The profile exhibits thick slow zones between line station 100 – 200 ft down to ~50 ft depth and line stations 450 to 650 ft with a maximum depth near 60 ft around line station 570 ft (Plate 6b). Maximum thickness in both areas reaches an elevation of 610 – 620 ft. A local high in the transition to 5,000 fps occurs around line stations 350 – 370 ft. The transition to 10,000 fps generally dips to the east along an uneven surface. The transition from 5,000 fps to 10,000 fps is 60 to 90 ft thick from line station 200 ft to the end of the line.

Spillway Left Abutment

Line 11

Line 11 is the only seismic line collected along the left abutment of the spillway. The line was collected in a northeast to southwest orientation on 15 December 2018 and extended for 858 ft (Table 1). Most of the line was characterized by steep grassy slopes although thin soil over bedrock was observed around line station 549 ft and some spotty outcrops of bedrock were observed also around line station 621 ft. The slow zone (3,000 – 4,000 fps) is thickest (~ 50 ft) below the apex of the hill and toe of the slope (about 30 ft thick from the start of the line to about seismic line station 130 (Plate 7). The slow zone is relatively thin (10 to 20 ft) below the east facing slope between seismic line stations 140 to 550 ft. The transition to higher velocity rock (>10,000 fps) occurs about 85 to 100 ft below the surface along the east facing slope but reaches about 180 ft starting around line station 680 ft.

Spillway Upper Right Abutment

Lines 14 and 15 were collected in July 2019 in place of additional borings high up on the slope of the right abutment. The topography was challenging for seismic data collection with nearly 200 ft of vertical relief along Line 14 and 160 ft along Line 15. Data collection was further complicated by air temperatures between 100 and 105 °F and windy conditions in a thickly vegetated area on 26 July.

Line 14

Line 14 was collected on 25 July 2019 in a north-northwest – south-southeast orientation. It extended for 573 ft and descended a steep slope along the right abutment (Plate 8a). Bedrock outcrops were observed between line stations 111 ft and 229 ft. Line 14 intersects Line 15 near line station 180 ft. Near surface velocity is above 4,500 fps to about line station 180 ft. Between line station 220 and 300 ft, velocity is below 3,000 fps down to depths of nearly 40 ft to elevation 825 ft. From line station 300 ft to the end of the line, there is a transitional zone that extends 20 to 60 ft below the ground surface where velocities are between 4,000 and 5,000 fps. High velocity rock (>10,000 fps) is encountered 120 to 180 ft below the ground surface along the length of the line. The shallow occurrence of high velocity rock is located between line stations 150 to 300 ft, where it is encountered 120 to 160 ft below the surface where bedrock was exposed at the ground surface.

Line 15

Line 15 was collected on 26 July 2019 in a nearly north – south orientation. It extended for 573 ft and descended a steep slope along the right abutment (Plate 8b). A thin veneer of soil was obseeved above weathered bedrock around line station 125 ft and extended to about line station 221 ft. Line 15 intersects Line 14 near line station 220 ft. Between line stations 100 and 200 ft, near surface velocity approaches or exceeds 5,000 fps. Over the remainder of the line, there is a layer of uneven thickness (20 to 40 ft) that exhibits velocities below 3,500 fps. The transition to higher velocity material is generally fast (over 20 – 30 ft) and velocities in excess of 10,000 fps are achieved within 85 to 100 ft of the surface, except near line stations 420 – 440 ft where a velocity of 10,000 fps is achieved near 60 ft depth.

Discussion

As the intent of this letter report is to document the geophysical survey so that the data can be provided to the design team, interpretation is intentionally omitted. Lithologic logs reflecting the field recorded weathering grade have been ovelaid on Plates 1 to 8 for informational purposes only. On these plots, the number in brackets behind the boring identification number represents offset distance between the line’s projection and the boring. The positive values indicate the boring is in the foreground (in front of the profile) while negative numbers indicate the boring is in the background (behind the profile). As the borings were hung in 3-dimensional space, the top of the boring may be above or below the projected ground surface of the profile depending on local topography

Reference

Hunter, L.E., 2014. Evaluation of rippable surface using seismic refraction data. Sacramento, California, Sacramento District, U.S. Army Corps of Engineers. Technical Memorandum to File: Geophysics Memorandum 2 dated 16 July 2014.

FIGURES

Figure 1. 2018 and 2019 seismic refraction line locations (red) relative to site boreholes.

Line work in background is Sheet V-103 from the 65% DDR Submittal. Dashed line indicates extent of proposed slope cut.

Figure 2. Field configuration for seismic data collection. (A) Geometrics Geode and 12-volt battery. Geodes were required every 24 stations and were daisy chained back to computer for data logging. (B) Field personnel swinging 20-lbs sledgehammer in background with computer display of stacked section showing in foreground. (C) Layout of Line 13.

A

C

B

Figure 3. Field configuration for seismic data collection. (A) 200-lbs accelerated weight drop (AWD) seismic source attached to trailer hitch of SUV. (B) Set-up at the start of Line

10. 20-lbs sledgehammer is attached to Geometric geode box (yellow) using trigger wire on spool. Yellow interconnect cable connects this geode to next geode (24 geophones away) down the line. Circular steel plate was the strike plate for the sledgehammer while the square aluminum plate in (A) was used at the strike plate for the AWD.

A

Figure 4. Field configuration for seismic data collection. (A) Geophone layout at start of Line 7 looking towards the east (Lake Success). (B) AWD on back of USGS SUV.

A B

Figure 5. Photographs showing data collection and monitor window during the collection of Line 6, shot point at 723 ft along the line. (A) First shot and (B) eighth shot (8 stack).

Note the improved clarity in the record from the first shot to last due to stacking.

A

PLATES

1F -01

-04 (0

1F -01

-05 (-2

1F -01

-06

1F -03

-02

1F -03

-06

8)

2F -03

-02 A (+

1F -19

-08 (0

1F -19

-10

1F -19

-13 (-2

0 100 200 300 400 500 600 700 800

0 100 200 300 400 500 600 700 800 900 1000

1F -03

-03

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1F -03

-05

1F -03

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1F -19

-09

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1F -19

-12

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1F -19

-14 (-3

1F -19

-16 (-3

6)

1F -19

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Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

A

B

Distance (ft)

El ev at io n (ft

Distance (ft)

El ev at io n (ft

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 1

Line 3

Spillway (Upper)

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West East

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Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 7

Intersection w ith Line 4

Intersection w ith Line 8

Intersection w ith Line 4

Intersection w ith Line 8

Intersection w ith Line 7

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

Distance (ft)

El ev at io n (ft

1F -01

-04

1F -03

-0 (-2

2)

1F -03

-04 (-3

2)

2F -03

-02 A (-2

2)

2F -03

-04 A (-3

2)

1F -19

-08 (-5

0 100 200 300 400 500

A

4 3 2 1

C

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A

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SU

C

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R ef ra ct io n

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US Army Corps of Engineers Sacramento District

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L.

H un te r

L.

H un te r

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P at te rm an n

4/

D R

A

FT

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 4

Spillway (Upper) Cross Lines

Northwest Southeast

0 100 200 300

1F -01

-04 (-3

2)

1F -03

-01 (0

1F -03

-05

4)

1F -03

-08 (-4

5)

1F -19

-07

1F -19

-08 (-2

1F -19

-10 (-3

6)

1F -19

-07 A (+

A

Distance (ft)

El ev at io n (ft

Line 8

Southwest Northeast

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 12

Intersection w ith Line 1

Intersection w ith Line 3

Intersection w ith Line 4 ith Line 3

-08 (-4

2)

0 100 200 300 400 500 600 700

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

B

Distance (ft)

El ev at io n (ft

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 6

Spillway (Lower)

North South

1F -03

-07

3)

1F -19

-23 (-4

4)

1F -19

-24 (-1

1)

0 100 200 300 400 500

Distance (ft)

El ev at io n (ft

A Line 5

North South

4 3 2 1

C

B

A

Plate

SU

C

C

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S

LW

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Se is m ic

R ef ra ct io n

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4-

D es ig ne d by

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N o:

D at e:

R ev

R ev ie w ed b y:

Su bm itt ed b y:

D es ig n fil e no

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Fi le n am e:

Pl ot d at e:

D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

D R

AF

T

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Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 3

Intersection w ith Line 7 ith Line 7

-05

1F -01

-06 (-1

9)

1F -01

-07 (-7

1F -01

-08

1F -19

-11 (-4

4)

1F -19

-12

1F -19

-16

1F -03

-07 (-5

9)

0 100 200 300 400 500 600 700 800

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

Distance (ft)

El ev at io n (ft

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 7

Spillway (Lower)

Southwest Northeast

4 3 2 1

C

B

A

Plate

SU

C

C

ES

S

LW

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Se is m ic

R ef ra ct io n

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D es ig ne d by

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N o:

D at e:

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D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

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H un te r

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D R

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FT

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 3 ith Line 1

1B -07

-29 (-1

5)

1F -01

-02 (-4

4)

1F -01

-03 (-4

5)

1F -56

-12

0 100 200 300 400 500 600 700

1B -07

-26 (-3

6)

1B -07

-26 A (-3

6)

1F -01

-01 (-2

8)

1F -01

-02

0 100 200 300 400 500 600 700

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

Distance (ft)

El ev at io n (ft

Line 10 West East

4 3 2 1

C

B

A

Plate

SU

C

C

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S

LW

AY

Se is m ic

R ef ra ct io n

Li ne s

D

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R ev

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D es ig n fil e no

Su bm itt al s ta tu s:

Fi le n am e:

Pl ot d at e:

D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

D R

AF

T

N um be rs in b ra ck et s re pr es en t o ffs et fr om s ei sm ic li ne po si tiv e va lu es in di ca te s bo rin g in fo re gr ou nd a nd n eg at iv e

) i nd ic at es b or in g in b ac kg ro un d C au tio n sh ou ld b e us ed p ro je ct in g co nt ac ts to p ro fil e

L.

H un te r

L.

H un te r

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P at te rm an n

4/

D R

A

FT

A

B

Distance (ft)

El ev at io n (ft

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 9

Right Abutment (lower) Southwest Northeast

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9 Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 10

Intersection w ith Line 13 ith Line 9

1B -07

-38 (-3

7)

1F -19

-17 (-3

6)

1F -19

-18 (-2

5)

0 100 200 300 400 500 600 700

1F -19

-20

1F -19

-21

0 100 200 300 400 500 600 700 800 900 1000

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

A

B

Distance (ft)

El ev at io n (ft

Distance (ft)

El ev at io n (ft

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 60 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground.

Line 12

Line 13

Right Abutment & Road Realignment

West East

South North

4 3 2 1

C

B

A

Plate

SU

C

C

ES

S

LW

AY

Se is m ic

R ef ra ct io n

Li ne s

D

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C R

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EN

TO

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4-

D es ig ne d by

D ra w n by

Sp ec

N o:

D at e:

R ev

R ev ie w ed b y:

Su bm itt ed b y:

D es ig n fil e no

Su bm itt al s ta tu s:

Fi le n am e:

Pl ot d at e:

D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

D R

AF

T

N um be rs in b ra ck et s re pr es en t o ffs et fr om s ei sm ic li ne po si tiv e va lu es in di ca te s bo rin g in fo re gr ou nd a nd n eg at iv e

) i nd ic at es b or in g in b ac kg ro un d C au tio n sh ou ld b e us ed p ro je ct in g co nt ac ts to p ro fil e

L.

H un te r

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H un te r

K.

P at te rm an n

4/

D R

A

FT

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Intersection w ith Line 8 ith Line 10

-03

-10

1F -88

-01

1F -88

-02

1F -88

-03

2F -03

-10 A (+

1F -19

-01

) 1F

-19 -02

1F -19

-03

0 100 200 300 400 500 600 700 800

850 Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

Distance (ft)

El ev at io n (ft

Line 11

Left Abutment

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 65 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in foreground

* Boring 1F-88-01 inclined: dips 65° at a bearing of 346°

* Boring 1F-88-02 inclined: dips 65° at a bearing of 326°

* Boring 1F-88-03 inclined: dips 65.5° at a bearing of 330°

East West

4 3 2 1

C

B

A

Plate

SU

C

C

ES

S

LW

AY

Se is m ic

R ef ra ct io n

Li ne

D

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TO

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4-

D es ig ne d by

D ra w n by

Sp ec

N o:

D at e:

R ev

R ev ie w ed b y:

Su bm itt ed b y:

D es ig n fil e no

Su bm itt al s ta tu s:

Fi le n am e:

Pl ot d at e:

D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

D R

AF

T

N um be rs in b ra ck et s re pr es en t o ffs et fr om s ei sm ic li ne po si tiv e va lu es in di ca te s bo rin g in fo re gr ou nd a nd n eg at iv e

) i nd ic at es b or in g in b ac kg ro un d C au tio n sh ou ld b e us ed p ro je ct in g co nt ac ts to p ro fil e

L.

H un te r

L.

H un te r

K.

P at te rm an n

4/

D R

A

FT

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000 ith Line 4

0 100 200 300 400 500 600

1B -07

-32

7)

1F -01

-02 (-1

1F -19

-05

1)

4 3 2 1

C

B

A

Plate

SU

C

C

ES

S

LW

AY

Se is m ic

R ef ra ct io n

Li ne s

D

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D

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N

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TR

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T

SA

C R

AM

EN

TO

, C

A

4-

D es ig ne d by

D ra w n by

Sp ec

N o:

D at e:

R ev

R ev ie w ed b y:

Su bm itt ed b y:

D es ig n fil e no

Su bm itt al s ta tu s:

Fi le n am e:

Pl ot d at e:

D ra w in g sc al e:

US Army Corps of Engineers Sacramento District

D R

AF

T

N um be rs in b ra ck et s re pr es en t o ffs et fr om s ei sm ic li ne po si tiv e va lu es in di ca te s bo rin g in fo re gr ou nd a nd n eg at iv e

) i nd ic at es b or in g in b ac kg ro un d C au tio n sh ou ld b e us ed p ro je ct in g co nt ac ts to p ro fil e

L.

H un te r

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H un te r

K.

P at te rm an n

8/ v . 1

D R

A

FT

4 3 2 1

C

B

A

1B -07

-36 (-2

8)

1F -01

-01

7)

1F -19

-04 (-8

6)

0 100 200 300 400 500 600

Intersection w ith Line 14

Intersection w ith Line 15

Legend

Fill

TBD

decomposed highly moderately slightly unweathered

Vertical exaggeration: 1x

A B

Line 14

North SouthNorthwest Southeast

Distance (ft)

El ev at io n (ft

Distance (ft)

El ev at io n (ft

Line 15 Right Abutment (Upper)

Note:

* Orientation of profile presentation is relative to direction in which the seismic line was collected in the field

* Available borings located within 110 ft of each line have been projected onto the profile.

* Weathering grade as recorded in the field logs is projected for lithology

* Number following borehole ID indicates distance (in ft) from line relative to projection displayed: negative distance (- #) in background, and the positive values (+ #) are in fore-ground.

Ve lo ci ty

(f t/s ec

10000 11000 12000 13000 14000 15000 16000 17000 18000 19000

Li ne

Line 10

Line 13

Line 3

Line 11

Lin e 7

Line 1

Line 9

Line 6

Li ne

Line 4

Line 15Line 14

Li ne

6583000

6583000

6583500

6583500

6584000

6584000

6584500

6584500

0 250 500 750 1,000125 ft

APPENDIX A

Appendix A

Seismic Refraction Lines December 2018 & July 2019

Seismic refraction line locations and positions relative to borings

Se is m ic

P -w av e

Re fr ac tio n Li ne

Su cc es s

Da m

S pi llw ay

De ce m be r 2

Seismic P-wave Refraction Line 11 Success Dam Spillway – December 2018

TBA

Status

• Preliminary picks made

• Data transferred to USGS for review

• Data will be edited and then inverted

• Final inversion

Appendix B

Travel-time curves for seismic refraction lines 1 through 15

(plots are used to evaluate coverage, data density, and first break picks as a quality control check)

Li ne

Li ne

Li ne

Li ne

TB

D

TB

D

C ol or ed b y ro le

: b la ck (o rig in al s pr ea d) re d

(s pr ea d af te r r ol l a lo ng

Li ne

Li ne

Li ne

TB

D

TB

Li ne

Li ne

Li ne

TB

D

TB

D

TB

D

C ol or ed b y so ur ce : g re y

(A W

D re d

(s le dg eh am m er

Bl ac k lin e in di ca te s ac tiv e lin e w he n sc re en g ra b ta ke n

Li ne

TB

D

TB