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c. Site Geology, General. - Block 9 is located in an area of relatively flat lying sedimentary formations. Recent eolian and alluvial deposits cover claystone, shale, siltstone, and sandstone of the Tertiary Nacimiento Formation (Tn), conglomeratic sandstone of the Cretaceous/Tertiary Ojo Alamo Formation (KToa), and shale and sandstone of the Cretaceous Kirtland Shale (Kk). These formations represent continental deposits accumulated on flood plains. The Nacimiento Formation rests unconformably on the Ojo Alamo Formation.
The following is a brief description of the Cretaceous, Tertiary, and Quaternary geologic units which will be encountered during construction.
(1) Surficial Deposits. - Quaternary Eolian (Qeo) - Quaternary eolian deposits overlie bedrock throughout most of Block 9 at depths ranging from 1 foot to greater than 39.1 feet, as encountered in DH-B9-136. For more detail, see each specific geologic log and the station to station geologic description.
These deposits consist predominantly of wind-deposited sand containing varying amounts of non-plastic (silty) fines, plastic (clayey) fines, and traces of chert gravel scattered in widely intermittent zones, thin layers, and lenses. Included within this unit are occasional layers of alluvial deposits which are not differentiated on the geologic logs due to similarity of engineering properties. The alluvial deposits consist of clayey fines and plastic to non-plastic, silty fines with differing amounts of predominantly fine to medium sand.
The deposits vary in consistency from very soft (thumb will penetrate soil more than 1 inch) to hard (thumb will not indent soil but soil is readily indented with thumbnail). Secondary concentrations of calcium carbonate are pervasive throughout the majority of the eolian deposits in Block 9. These concentrations generally occur at or just below ground surface and continue sporadically with depth. Calcium carbonate is found both in minute, faint mottled zones, pockets, and stringers less than 0.1-foot thick, and in intermittent light, moderate, and heavily concentrated zones occasionally up to several feet in thickness. Cementation of the soil in these areas is predominantly weak (crumbles or breaks with handling or little finger pressure) to occasionally strong (will not crumble or break with finger pressure).
Isolated lenses of low- to high-plasticity (clayey) fines are encountered within these deposits. High plasticity, fine-grained soils overlying claystone and shale bedrock are derived directly from local weathering and decomposition of these rock units.
(2) Bedrock. - Bedrock that will be encountered during construction of Block 9 includes shale, claystone, and sandstone of the Tertiary Nacimiento Formation (Tn), and sandstone and shale of the Cretaceous/Tertiary Ojo Alamo Sandstone (KToa). Explorations encountered the basal portion of the Nacimiento Formation and the upper portion of the Ojo Alamo Sandstone. The Nacimiento Formation has been locally eroded from the area leaving only the Ojo Alamo Sandstone underlying eolian materials. Bedding in the Nacimiento Formation near the Block 9 Stage 2 area strikes N60W to N75W, dipping 0 to 5NE. Attitude of bedding in the Ojo Alamo Sandstone was not determined due to its lack of exposure.
(a) Nacimiento Formation (Tn). - Bedrock of the Nacimiento Formation overlies the Ojo Alamo Sandstone and was encountered in subsurface explorations predominantly in the western portion of the Block 9 Stage 2.
The Nacimiento Formation bedrock encountered in these explorations represents the basal portion of the unit. Eolian deposits overlie the Nacimiento Formation. The Nacimiento Formation consists of shale and claystone with some interbedded sandstone and siltstone. Thickness of individual beds ranges from less than 1 inch to more than 10 feet. Due to the lenticular, discontinuous nature of individual beds and the spacing of subsurface explorations, correlation of bedrock units was not possible.
The shale, claystone, and siltstone beds of the Nacimiento Formation are typically dark gray, gray, greenish-gray, and reddish-brown. They are laminated to thinly bedded, occasionally fissile, decomposed to intensely weathered at the top of bedrock, becoming moderately to slightly weathered below 1 to 5 feet in depth, and very soft to moderately soft. These units typically slake rapidly when exposed to air or water. Samples from subsurface explorations would partially to completely disaggregate after 30 minutes of immersion in water. Hairline cracks generally appear between 5 and 60 minutes after exposure to air. Soils derived from the decomposition of shale and claystone bedrock often are highly plastic and exhibit shrink/swell characteristics.
Two lithologically different types of sandstone were encountered in explorations for Block 9. The two types of sandstone differ, with one being poorly cemented, friable, softer, and coarser grained, while the other is finer grained, well cemented, and much harder. The two types of sandstone are as follows:
(aa) Sandstone - Consists of fine to coarse, angular to subrounded quartz, with traces of quartz gravel. The sandstone is light gray to brown, weakly cemented to uncemented, intensely weathered to decomposed, and very soft. Bedding and joint orientations were not observed due to the degree of weathering.
(bb) Sandstone - Consists of fine to medium, angular to subrounded quartz, with traces of quartz gravel. The sandstone is gray to brown, moderately to well cemented, moderately weathered, and moderately soft to moderately hard. A few isolated portions are partially to completely cemented with silica, well indurated, and hard.
(b) Ojo Alamo Sandstone (KToa). - The Ojo Alamo Sandstone is overlain by surficial deposits throughout much of the Block 9 Stage 2 area and is locally overlain by bedrock of the Nacimiento Formation. The Ojo Alamo Sandstone was encountered in subsurface explorations along most of the pipeline lateral alignments. Two small outcrops of the Ojo Alamo Sandstone were observed along the B0.1G lateral alignment.
The sandstone is predominantly quartzose, fine to coarse-grained, angular to subrounded sand with locally significant zones of conglomerate. The sandstone is typically soft to very soft and friable where intensely weathered to decomposed, and moderately soft to moderately hard where fresh to slightly weathered. The top 1 to 12 feet of bedrock is intensely weathered to decomposed, and was often recovered in a loose, soil-like condition. Quartz cobbles up to 9 inches in diameter have been encountered in the sandstone in nearby areas. Thin lenses of shale and siltstone are also present within this unit.
(3) Groundwater Occurrence. – Groundwater was encountered on top of the bedrock surface in the vicinity of the B0.9L and B0.1R pumping plants. The source of this water is seepage from the adjacent Burnham Lateral Reach 1 canal. Groundwater was not encountered in any of the explorations conducted for Block 9 Stage 2 pipeline laterals.
(4) Pumping Plant B0.1R - The location of features discussed in this section is shown on drawing G2 (809-D-6199). Pumping Plant B0.1R is located along Burnham Lateral Reach 1 canal, just downstream of Gallegos Discharge Pipeline outlet. The turnout structure is located at station 2+97 of Burnham Lateral Reach 1 canal.
The B0.1R pumping plant site was explored by three drill holes, PR-99, DH-B9-138, and DH-B9-139, with -138 being located at the elevated tank site. Standard Penetration Test (SPT) results were obtained in the eolian deposits in drill hole PR-99. In-place dry unit weights were obtained in the other two drill holes. The data is summarized in Table 1C.
Eolian deposits (Qeo) overlie bedrock at the B0.1R Pumping Plant site and consist predominantly of silty sand, poorly graded sand with silt, and clayey sand. The deposits range in thickness from 36.2 feet in drill hole DH-B9-139 to greater than 39.1 feet in DH-B9-138. In-place dry unit weights of the eolian materials in drill holes DH-B9-138 and -139 ranged from 92.2 to 119.4 pounds per cubic foot with an average of 109.0 pounds per cubic foot. Low densities of 92.2 and 92.5 pounds per cubic foot were obtained in drill hole DH-B9-139 in a lean to fat clay (CL/CH) interval from 16.0 to 18.5 feet in depth and in silty sand (SM) from 26.0 to 28.5 feet in depth. Standard Penetration Resistance tests performed in drill hole PR-99 ranged from 34 to 71 blows per foot.
A lean to fat clay was encountered in drill hole DH-B9-139 from 15.2 to 19.9 feet (El. 6182.3 to 6177.6) and lean clay was encountered in drill hole PR-99 between elevations 6182.3 and 6180.6. A sample of the clay from DH-B9-139 was classified in the FCCF Laboratory as fat clay and indicated a very high potential for expansion. The clay showed a Plasticity Index of 48.6, Liquid Limit of 68.9, and a Shrinkage Limit of 7.1. Overexcavation will likely be required to remove the clay from pumping plant invert. Similar clay was encountered at the elevated tank site in drill hole DH-B9-138 at a depth of 27.4 to 28.7 feet (El. 6173.3 to 6172.0). This clay was laboratory classified as fat clay with a Plasticity Index of 33.6, Liquid Limit of 53.6, and Shrinkage Limit of 9.2.
Sandstone of the Cretaceous/Tertiary age Ojo Alamo Formation (KToa) was encountered at a depth of 36.2 feet in drill hole DH-B9-139. Bedrock was not encountered in PR-99, drilled to a depth of 27.0 feet, nor in DH-B9-138, drilled to a depth of 39.1 feet. The sandstone is intensely weathered, soft, and friable. The cementation increases slightly with depth, but drill hole core samples still crumble with manual handling.
Saturated material with some free water was encountered in drill hole DH-B9-139 at a depth of approximately 30.0 feet. The water likely represents localized canal seepage which is present in pervious materials overlying bedrock. Groundwater was not encountered in drill hole PR-99 (drilled prior to construction of the canal) or in DH-B9-138.
(5) Pumping Plant B0.9L - Pumping Plant B0.9L is located left of Burnham Lateral Reach 1 canal station 48+60. The turnout structure has yet to be designed and constructed at this location. The topography and location of exploration are shown on drawing 56 (809-D-6009). This pumping plant location is approximately 0.5 miles north of the originally proposed B1.7L pumping plant. It was moved to this location to avoid excavation into the Nacimiento claystone and shale. These materials have expansive properties which have resulted in severe damage to the concrete lining on Burnham Lateral Reach 1 canal.
Pumping Plant B0.9L was explored by four drill holes, DH-B9-140, -141, -148, and -149. Drill holes DH-B9-140 and -141 were drilled at a nearby alternate pumping plant location approximately 140 feet south of the B0.9L plant. Subsurface information from these holes may be pertinent to the current plant location due to their close proximity. Drill hole DH-B9-148 was drilled in the sump area of the pumping plant and DH-B9-149 was drilled in the vicinity of the elevated tank structure. In-place dry unit weights were obtained in drill holes DH-B9-140, -141, and 149. Samples for Proctor density analysis were obtained in drill holes DH-B9-141 and -149. The data is summarized in Table 1C and is included in the drill hole logs and is also shown on the laboratory summary sheets.
The B0.9L pumping plant location is near the crest of a large sand dune which slopes eastward from the canal right-of-way. The eolian deposits overlie claystone bedrock of the Nacimiento Formation at the pumping plant site and consist of silty sand and poorly graded sand with silt. The eolian deposits range in thickness from 19.4 feet in drill hole DH-B9-149 to 22.9 feet in DH-B9-140. In-place dry unit weights range from 90.9 pounds per cubic feet to 106.9 pounds per cubic feet with an average of about 100.1. Low densities of 90.9 and 91.5 pounds per cubic feet were obtained in silty sand at depths of 11.0 to 13.5 feet in drill hole DH-B9-141, and 10.5 to 13.0 feet in DH-B9-142.
Bedrock encountered at Pumping Plant B0.9L is claystone of the Nacimiento Formation. The claystone is blocky with indistinct bedding, occasionally fissile in spots, moderately to intensely weathered, and moderately soft to soft. It slakes rapidly when placed in water and also slakes when exposed to air, developing desiccation cracks upon drying. It is anticipated that excavation at the pumping plant will terminate in the overlying eolian deposits, leaving a minimum of about 10 feet of silty sand and poorly graded sand with silt between invert grade and the top of the potentially expansive claystone.
(6) Pipeline Laterals, Station-to-Station - General. - The location of features discussed in this section are shown on the plan and profile drawings 4 (809-D-6037) through 22 (809-D-6055), and pumping plant drawings 42 (809-D-5995) and 56 (809-D-6009). Station-to-Station geology descriptions presented below are based on site specific investigations performed along the lateral alignments. For detailed descriptions, location and thickness of surficial deposits and bedrock descriptions, see the specific plan and profile drawing or drill hole log. Conditions encountered during explorations along the pipeline laterals do not necessarily reflect the in-place conditions at other locations along the lateral alignments. The location of the top of bedrock is known only where encountered during exploration and may vary significantly at other locations along the lateral alignment. Surface geology and drill hole stick logs are shown on the plan and profile drawings. Terms used to describe soils are based upon USCS visual and laboratory classifications. Bedrock descriptions are from criteria set forth in the USBR Engineering Geology Field Manual.
Groundwater was encountered only adjacent to the canal in two drill holes exploring subsurface conditions at pumping plant locations. The ground water was encountered in drill hole DH-B9-139, located at a previously considered site approximately 140 feet south of the B0.1R pumping plant site and in BH-B9-140, located at the B0.9L pumping plant. The groundwater originates from leakage from the adjacent canal. All other subsurface investigations were dry. The dry conditions reflect the water table at the time of investigation and could change during periods of high precipitation or seepage from nearby irrigation features.
(a) Lateral B0.1R. - Station 3+20 to Station 110+50 (Drawings 4 (809-D-6037) and 5 (809-D-6038)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits, shale of the Tertiary Nacimiento Formation (Tn) and sandstone of the Ojo Alamo Sandstone (KToa). Explorations used to investigate this lateral include drill holes DH-B9-79 through -81, and DH-B9-84 through -89.
Eolian deposits were encountered in all of the subsurface explorations and ranges in thickness from 6.5 feet in drill hole DH-B9-86 at station 75+11 to greater than 13.9 feet as encountered in drill hole DH-B9-84. The surficial deposits were predominantly silty sand (SM), with lesser amounts of poorly graded sand with silt (SP-SM), silty, clayey sand (SC/SM), and sandy lean clay s(CL). The deposits tested had in-place unit weights ranging from 97.2 to 106.9 pounds per cubic foot with an average of about 101.3 pounds per cubic foot. Proctor densities were run on samples from drill hole DH-B9-86, indicating a maximum density of 115.6 pounds per cubic foot.
Shale of the Nacimiento Formation was encountered at 9.7 feet in drill hole DH-B9-80 (station 20+68), at 10.9 feet in drill hole DH-B9-81 (station 37+07), and at 10.7 feet in drill hole DH-B9-87 (station 86+42). The shale is moderately to intensely weathered, and moderately soft. Sandstone of the Ojo Alamo Sandstone was encountered in drill hole DH-B9-86 located at station 75+11. The sandstone is predominantly fine-grained with occasional medium and coarse-grained interbeds. It is very intensely weathered, soil-like and is very soft to soft. In-place unit weights in the bedrock materials range from 101.5 pounds per cubic foot to 119.0 pounds per cubic foot. Augering was difficult through the bedrock materials, although auger refusal was not met.
(b) Laterals B0.1R-1.6R. - Lateral B0.1R-1.6R, Station 0+00 to Station 26+00 (drawing 6 (809-D-6039)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits and possibly shale of the Tertiary Nacimiento Formation (Tn). Drill holes DH-B9-90 and -91 were used to explore lateral B0.1R-1.6R.
(c) Lateral B0.1L. - Station 0+00 to Station 137+35 (drawings 7 (809-D-6040), 8 (809-D-6041), and 9 (809 D-6042)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits and sandstone of the Ojo Alamo Sandstone (KToa). Explorations used to investigate this lateral alignment consisted of drill holes DH-B9-67 through DH-B9-70, DH-B9-73 through DH-B9-75, and DH-B9-78.
Eolian deposits were encountered in all of the subsurface explorations for this lateral. The deposits were predominantly silty sand (SM) with some poorly graded sand with silt (SP-SM), and occasional lenses of clayey sand (SC), and sandy lean clay s(CL). Thickness of the surficial deposits encountered during exploration ranged from approximately 10.8 feet to greater than 13.7 feet in drill hole DH-B9-78. All of the deposits tested had in-place dry unit weights greater than 95.0 pounds per cubic foot, averaging about 103.0 pounds per cubic foot.
Sandstone bedrock of the Ojo Alamo Sandstone was encountered in drill hole DH-B9-75, located at station 91+67. The sandstone is thinly bedded, intensely weathered, and soft. Auger refusal was met at 10.8 feet in depth in drill hole DH-B9-69 located at station 30+65. Although sandstone or shale bedrock may be encountered during excavation throughout this area, no bedrock was recovered at the bottom of this hole.
(d) Laterals B0.1L-0.9L and B0.1L-1.7R. - Lateral B0.1L-0.9L, Station 0+00 to Station 28+80, and Lateral B0.1L-1.7L, Station 0+00 to Station 20+00, (drawing 10 (809-D-6043)): These laterals will be founded on Quaternary Eolian(Qeo) deposits, and shale of the Tertiary Nacimiento Formation (Tn). Explorations used to investigate these pipeline laterals consist of surface mapping and drill holes DH-B9-71 and -72 on Lateral B0.1L-0.91L and drill holes DH-B9-76 and -77 on Lateral B0.1L-1.7R.
Eolian deposits were encountered in thickness ranging from 9.2 feet in drill hole DH-B9-77 to 13.5 feet in DH-B9-76. The deposits were predominantly silty sand (SM), clayey, silty sand (SM/SC), and poorly graded sand (SP). Test results for in-place unit weight in drill hole DH-B9-72 ranged from 102.5 to 105.0 pounds per cubic foot with an average of about 104.0 pounds per cubic foot.
Shale of the Nacimiento Formation was encountered at a depth of 9.2 feet in drill hole DH-B9-77, located at station 20+06 on lateral B0.1L-1.7R. Auger refusal was met in this hole at a depth of 11.1 feet. The shale is blocky and occasionally sandy, intensely weathered, and soft.
(e) Lateral B0.1G. - Station 1+20 to Station 171+39, (drawings 11 (809-D-6044) through 14 (809-D-6047)): Excavation along this lateral will encounter Quaternary Eolian (Qeo) deposits and bedrock of the Cretaceous/Tertiary Ojo Alamo Sandstone (KToa). Explorations used to investigate the B0.1G consist of drill holes DH-B9-92 through -99 and drill holes DH-B9-101 through -106.
Eolian deposits are present at the surface and were encountered to depths ranging from 5.9 feet in drill hole DH-B9-101 to greater than 13.9 feet in drill hole DH-B9-102. The deposits consist predominantly of silty sand (SM) with occasional zones of poorly graded sand with silt (SP-SM), clayey, silty sand (SM/SC), and sandy lean clay s(CL). In-place unit weights in the deposits ranged from 92.0 to 109.1 pounds per cubic foot with an average of 101.2 pounds per cubic foot.
Sandstone of the Ojo Alamo Sandstone was encountered in six drill holes from station 85+16 (drill hole DH-B9-98) to the end of the alignment at station 169+20 (drill hole DH-B9-106). The sandstone was encountered at a depth of 12.3 in DH-B9-98, 11.1 feet in DH-B9-99, 5.9 feet in DH-B9-101, 12.2 feet in DH-B9-103, 6.6 feet in DH-B9-105, and 6.5 feet in DH-B9-106. The sandstone is intensely to moderately weathered, moderately soft, light gray to tan, and is friable with light to heavy hand pressure. Auger refusal was met in sandstone at a depth of 12.5 feet in drill hole DH-B9-99.
(f) Lateral B0.1G-0.9R. - Station 0+00 to Station 116+80 (drawings 15 (809 D-6048) and 16 (809-D-6049)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits and sandstone of the Cretaceous/Tertiary Ojo Alamo Sandstone (KToa). Explorations used to investigate this lateral include drill holes DH-B9-107 through -115.
Eolian deposits were encountered in all of the subsurface explorations, ranging in thickness from 4.1 feet to greater than 13.5 feet. Materials encountered were predominantly silty sand (SM), with lesser amounts of sandy silt s(ML). In-place dry unit weights ranged from 99.4 to 112.3 pounds per cubic foot with an average of 104.1 pounds per cubic foot.
Sandstone bedrock of the Ojo Alamo Sandstone underlies the eolian deposits and was encountered in 4 of the 9 holes drilled along the alignment. The sandstone was encountered at depths of 8.2 feet in drill hole DH-B9-107, 5.1 feet in DH-B9-109, 12.8 feet in DH-B9-112, and 4.1 feet in DH-B9-114. The sandstone is intensely weathered to very intensely weathered and soft to moderately soft. Auger refusal was met at a depth of 11.7 feet in drill hole DH-B9-114.
(g) Lateral B0.1G-0.9R-0.5R. - Station 0+00 to Station 108+50 (drawings 17 (809 D-6050) and 18 (809-D-6051)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits. Explorations used to investigate this lateral include drill holes DH-B9-116, and DH-B9-118 through -124.
Eolian deposits consist predominantly of silty sand (SM) with lesser amounts of clayey sand (SC), sandy silt s(ML), and sandy lean clay s(CL). Thickness of the deposits encountered in the explorations ranges from 1.7 feet in DH-B9-122 to greater than 13.4 feet in DH-B9-124. In-place unit weights of the eolian deposits range from 93.6 to 105.3 pounds per cubic foot with an average of about 99.4 pounds per cubic foot. Proctor densities from drill hole DH-B9-121 indicated a maximum density of 117.9 to 119.7 pounds per cubic foot.
Sandstone bedrock of the Ojo Alamo Sandstone (KToa) occurs near the surface along much of the B0.1G-0.9R-0.5R lateral alignment and was encountered in 5 of the 8 drill holes exploring the lateral. The sandstone was encountered at a depth of 2.3 feet in drill hole DH-B9-116, 2.2 feet in DH B9 118, 10.5 feet in DH-B9-120, 7.6 feet in DH-B9-121, and 1.7 feet in DH-B9 122. The sandstone is intensely weathered to occasionally very intensely weathered and predominantly soft. In-place dry unit weights taken in the weathered sandstone in drill hole DH-B9-118 range from 107.5 to 122.4 pounds per cubic foot. The sandstone was sufficiently hard and caused auger refusal at depths of 8.5 feet in drill hole DH-B9-116, at 9.3 feet in DH-B9-118, 12.4 feet in DH-B9-120, and at 7.4 feet in DH-B9-122.
(h) Lateral B0.1G-0.9R-0.5R-1.4R. - Station 0+00 to Station 32+00 (drawing 19 (809 D-6052)): This lateral will be excavated in Quaternary Eolian (Qeo) deposits. Explorations used to investigate this lateral include drill holes DH-B9-125 through -127.
Eolian deposits consisted of predominantly silty sand (SM) and silty sand to silt (SM/ML) with occasional lenses of silty, clayey sand (SC/SM) and clayey sand (SC). The deposits were encountered in thickness ranging from 2.7 feet in drill hole DH-B9-126 to greater than 13.6 feet in DH-B9-125 and DH-B9-127.
Ojo Alamo Sandstone (KToa) was encountered in drill hole DH-B9-126 at a depth of 2.7 feet. The sandstone is conglomeratic, intensely weathered and soft to moderately soft. The integrity of the sandstone increased with depth, and auger refusal was met at 7.4 feet in depth. The in-place dry unit weight of the weathered sandstone was 104.4 pounds per cubic feet from 3.6 to 6.1 feet in depth.
(i) Laterals B0.9L and B0.9L-0.4L. - Lateral B0.9L, Station 0+00 to Station 110+00 (drawings 20 (809-D-6053) through 22 (809-D-6055), and Lateral B0.9L-0.4L (drawing 22 (809-D-6055): These pipeline laterals will be excavated in Quaternary Eolian deposits and bedrock of the Tertiary Nacimiento Formation (Tn) and the Cretaceous/Tertiary Ojo Alamo Sandstone (KToa). Drill holes DH-B9-142 through -147, and DH-B9-131, and -135 were used to explore subsurface conditions on Lateral B0.9L. Explorations on Lateral B0.9L-0.4L included drill holes DH-B9-128, and -129.
Eolian deposits were encountered from ground surface in all the explorations on Laterals B0.9L and B0.9L-0.4L, and ranges in depth from 2.6 feet in drill hole DH-B9-147 to greater than 13.4 feet in DH-B9-129. The deposits are predominantly silty sands (SM) with some clayey sand (SC), and occasional lenses of sandy lean clay s(CL). In-place unit weights range from 93.6 to 108.1 pounds per cubic foot with an average of approximately 99.7 pounds per cubic foot.
Bedrock consisting of claystone, shale, and sandstone of the Nacimiento Formation underlies the eolian deposits throughout Lateral B0.9L and was encountered in all of the subsurface explorations. The top of bedrock surface is relatively shallow throughout much of this lateral with the shallowest occurrence being 2.6 feet in depth in drill hole DH-B9-147 (see drawings 20 (809-D-6053) through 22 (809-D-6055)). The claystone and shale units are generally blocky to fissile, moderately to intensely weathered, and moderately soft to soft. The sandstone is mostly fine to coarse-grained, locally conglomeratic, intensely weathered, moderately soft and friable. In DH-B9-135 sandstone was encountered at a depth of 3.4 feet; auger refusal was met at 4.2 feet. A layer of hard sandstone was encountered in drill hole DH-B9-142 (Lat. B0.9L station 13+14) from 7.3 to 8.3 feet in depth. If this sandstone is encountered during excavation for the pipeline lateral, it may cause some difficulty in excavation. The hollow stem auger was able to penetrate the sandstone only because of its fractured nature at this location. Remnants of this sandstone layer are also scattered on the ground surface near the alignment between approximate stations 60+00 and 70+00, indicating that it may also be encountered at other locations along Lateral B0.9L.
The Ojo Alamo Sandstone was encountered on the B0.9L-0.4L alignment in drill hole DH-B9-128 at a depth of 11.9 feet. The sandstone at this location is medium grained, decomposed, and very soft.
d. Geologic Considerations. -
(1) Stability of Earth Materials. - This section includes information on natural slope stability and recommends temporary and permanent cut slopes for both surficial deposits and bedrock. The stability of cut slopes is dependent upon composition of materials and moisture conditions.
(a) Natural Slope Stability. - The stability of surficial deposits in the Block 9 area is dependent primarily on material composition. Most of the terrain in the project area is relatively flat lying, lacking major topographic features. Prominent features in the area are longitudinal sand dunes up to 25 feet high, 100 feet wide, and 1/4 mile or more in length. The upper portions of these dunes are composed of poorly graded sand (SP), poorly graded sand with silt (SP-SM), and silty sand (SM). The slopes of the dunes are typically flatter than 1.5:1. Where road cuts or arroyos cross the dunes, the slopes are stable at slopes of 1.5:1 or flatter. Natural slopes for clayey sands (SC) and silty, clayey sands (SC/SM) where exposed in arroyos and road cuts appear to be stable up to 1.5:1.
Numerous exposures of the Nacimiento Formation (Tn) are present south of the project area in a large arroyo draining the northeast side of Moncisco Mesa. Natural slopes along the edges of the arroyo range from approximately 5:1 to vertical, with most slopes at approximately 1:1. Exposures of the Ojo Alamo Sandstone (KToa) are found approximately 2 miles southeast of the project area in West Gallegos Canyon. Natural slopes at these outcrops are 1.5:1 to vertical.
(b) Temporary and Permanent Cut Slopes. - Recommendations for cut slopes in surficial deposits are based on the material type and texture. All cut slopes shall be constructed in accordance with the Reclamation Safety and Health Standards. Recommendations are for dry or adequately dewatered materials. Materials with excessive moisture will require further flattening for stability. Recommended cut slopes for type C soils, including poorly graded sands (SP), poorly graded sands with silt (SP-SM), and silty sands (SM), are 1.5:1. Recommended cut slopes for type B soils, including silty clayey sands (SC/SM) and clayey sands (SC) are 1:1. Lean to fat clays soils are classified as type B soils due to the presence of construction traffic, and should have cut slopes of 1:1 or flatter.
Cut slopes in bedrock will be dependent upon the rock type and degree of weathering. All decomposed to intensely weathered, very soft to soft bedrock will be classified as type B or type C soils depending upon the composition of the rock. Moderately weathered to fresh, moderately soft to hard bedrock can be classified as “stable rock” if all of the requirements of the Reclamation Safety and Health Standards are met.
(2) Excavation Considerations. - Common excavation can be used for all Eolian (Qeo) deposits that will be encountered. The materials encountered during subsurface explorations are similar to those encountered during the construction of Burnham Lateral West and Burnham Reach 1 canals and the Block 8 laterals. Both of these features were common excavation.
Most of the bedrock that will be encountered is substantially weathered and will be common excavation. Less weathered portions of the sandstone in the Ojo Alamo Sandstone (KToa), and the hard sandstone of the Nacimiento Formation (Tn), as encountered in drill hole DH-B9-142 on lateral B0.9L, will likely require ripping or other methods to facilitate removal. See the station-to-station descriptions, drawings, and the logs of exploration for further detail.
Low-density conditions of under 90 pounds per cubic foot were not encountered in any of the subsurface explorations for Block 9 Stage 1. Low-density conditions of under 90 pounds per cubic foot were encountered in explorations for the nearby Burnham Lateral West and the Block 8 laterals, predominantly in poorly graded sands (SP) and poorly graded sands with silt (SP-SM) in eolian deposits. Materials with similar properties could possibly be encountered during excavation of Block 9, Stage 1. Settlement could occur in areas of low-density materials where they are exposed to construction traffic vibrations, used in a load-bearing situation, or saturated beyond their optimum water content. Trench walls excavated steeper than the recommended cut slopes in these and all other deposits will require the use of protective measures in accordance with the Reclamation Safety and Health Standards.
Laboratory testing of the clay soils and fine-grained bedrock encountered during explorations indicate a high probability of expansion for some of these materials. Swelling and expansion problems could occur if these materials become saturated during or after construction.
Pervious materials for construction of the laterals can be obtained from dune deposits in the area. Materials suitable for construction will be limited to the poorly graded sands (SP) and poorly graded sands with silt (SP-SM). The use of earth materials for construction purposes will have to be approved by the COR prior to use.
1.3.13 ELECTRIC POWER FOR CONSTRUCTION PURPOSES
a. General. The Government will provide the power required for onsite testing of the installed equipment. The Contractor shall make all necessary arrangements and shall provide all electric power required for construction purposes. This shall include providing all necessary transmission lines, distribution circuits, transformers, and other electrical equipment required for distributing the power to the place or places of use by the Contractor.
Power for testing either pumping plant B 0.1R or B 0.9L will not be available between November 1 and March 15.
At the termination of the contract under these specifications, the Contractor shall dismantle and remove all distribution lines serving the Contractor’s installations, or those of subcontractors, that are not part of the permanent power installation.
b. Cost. No direct payment will be made to the Contractor for providing electric power for construction purposes, and the cost thereof shall be included in the prices bid in the schedule for other items of work.
1.3.14 WATER FOR CONSTRUCTION PURPOSES
a. General. The Contractor shall furnish all water required for construction purposes, except that the Government will provide all water required for testing the pump units and pipe laterals. Water for testing of the pumping units and pipe laterals will be available in Burnham Lateral West and Burnham Lateral Reach 1 during the irrigation season.
Water from the San Juan River has been tested by the Government and approved for concrete mixing and curing water, except during periods of runoff when the water may be too turbid for concrete mixing. The Contractor will be required to obtain a State permit to use water from the San Juan River.
Water from the Gravity Main Canal, Amarillo Canal, and Burnham Lateral West may be used during the irrigation season. No water will be stored in the canals during nonirrigation season. The irrigation season begins about March 1 and ends about November 15. The water in these canals is managed by NAPI and owned by the Navajo Tribe. If this source of water is to be used, the Contractor shall contact NAPI to determine the availability, cost of water, and cost of service for delivery of water to the construction site. The Contractor shall obtain a Water Permit from the Navajo Tribe: The Navajo Nation, Department of Water Resources, Attn: Water Code Administration, PO Box 678, Fort Defiance, Arizona 86504: telephone (520) 729 4130 and (520) 729 4132, FAX (520) 729 4126. The permit for service may be obtained from NAPI at the following address: O&M Director, PO Drawer 1318, Farmington NM 87499, telephone: 505 326 2970 or 327 5251. The Contractor will have to pay the Navajo Nation for the cost of water and will also have to pay NAPI for the cost of service for delivery.
Water required for use in concrete shall meet the requirements of paragraph 5.2.5.
b. Cost. The cost of furnishing water and of providing necessary facilities and conveying water to points of use shall be included in the prices bid in the schedule for other items of work.
SECTION 1.4 SAFETY
1.4.1 SAFETY OF THE PUBLIC
Roads subject to interference by the work shall be kept open or suitable temporary passages through the work shall be provided and maintained by the Contractor. The Contractor shall provide, erect, and maintain all necessary barricades, suitable and sufficient flasher lights, flaggers, danger signals, and signs, and shall take all necessary precautions for the protection of the work and the safety of the public.
If directed, the Contractor shall erect such additional warning and directional signs in connection with the work as may be required by the Government.
Lanes closed to traffic shall be protected by effective barricades on which shall be placed acceptable warning and detour signs. All barricades and obstructions shall be illuminated at night, and all lights shall be kept burning from sunset until sunrise.
No construction work along public or private roads may proceed until the Contractor has proper barricades, flasher lights, flaggers, signals, and signs in place at the construction site.
Specific signs, signals, barricades, and flagger requirements are detailed in sections 9 and 19 of Reclamation's 2001 publication "Reclamation Safety and Health Standards" and the American National Standards Institute "Manual on Uniform Traffic Control Devices for Streets and Highways" (ANSI D6.1).
The cost of complying with this paragraph shall be included in the prices bid in the schedule for other items of work.
1.4.2 SUBMISSION OF MATERIAL SAFETY DATA SHEETS FOR HAZARDOUS MATERIALS
After award of contract, the Contractor shall submit updated List of Hazardous Materials (LHM) and Material Safety Data Sheets (MSDS) in accordance with the requirements of paragraph (e) of the clause at FAR 52.223 3, "Hazardous Materials Identification and Safety Data."
The Contractor shall submit the updated LHM and completed MSDS and identification and certification for each material to the Construction Engineer, 2200 Bloomfield Highway, Farmington NM 87401 8110. The Contractor shall not deliver any hazardous material to the jobsite which was not included on the original LHM prior to acceptance of the Contractor's MSDS by the Construction Engineer.
The cost of complying with this paragraph shall be included in the applicable prices bid in the schedule for the items of work for which the hazardous materials are required.
1.4.3 FIRST AID AND MEDICAL FACILITIES
a. General. The Contractor shall establish onsite first aid and medical facilities in accordance with section 5 of Reclamation's 2001 publication "Reclamation Safety and Health Standards."
b. Cost. The cost of providing the above described first aid and medical facilities shall be included in the prices bid in the schedule for other items of work.
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