Geotechnical Engineering Report

City of Conroe 2014 Surface Water System Improvements Water Plants Conroe, Texas August 6, 2014 Terracon Project No. 97145017

Prepared for: Lockwood Andrews & Newman, Inc. Houston, Texas

Prepared by: Terracon Consultants, Inc. Conroe, Texas

August 6, 2014

Lockwood Andrews & Newman, Inc. 2925 Briarpark Drive, Suite 400 Houston, Texas 77042-3720

Attn: Ms. Melissa C. Mack, P.E. Project Manager P: 713.821.0436 E: [email protected]

Re: Geotechnical Engineering Report City of Conroe 2014 Surface Water System Improvements Water Plants Conroe, Texas Terracon Project No. 97145017

Dear Ms. Mack:

Terracon Consultants, Inc. (Terracon) is pleased to submit our geotechnical engineering report for the project referenced above in Conroe, Texas. We trust that this report is responsive to your project needs. Please contact us if you have any questions or if we can be of further assistance.

We appreciate the opportunity to work with you on this project and look forward to providing additional geotechnical engineering and construction materials testing services in the future.

Sincerely, Terracon Consultants, Inc. (Texas Firm Registration No.: F-3272)

Simon Bandza, E.I.T. Bobbie S. Hood, P.E. Staff Geotechnical Engineer Geotechnical Services Manager

Enclosures

Copies Submitted: Addressee: (2) Bound (1) Electronic

Terracon Consultants, Inc. 11133 I-45 South, Building T Conroe, Texas 77302 P [936] 634 5044 F [936] 634 8177 terracon.com

TABLE OF CONTENTS Page EXECUTIVE SUMMARY ...... i 1.0 INTRODUCTION ...... 1 2.0 PROJECT INFORMATION ...... 1 2.1 Project Description ...... 1 2.2 Site Description ...... 2 3.0 SUBSURFACE CONDITIONS ...... 2 3.1 Geology ...... 2 3.2 Typical Profile ...... 3 3.3 Groundwater ...... 5 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION ...... 5 4.1 Geotechnical Considerations ...... 5 4.2 Earthwork ...... 6 4.2.1 Compaction Requirements ...... 7 4.2.2 Wet Weather/Soft Subgrade Considerations ...... 7 4.2.3 Grading and Drainage ...... 8 4.3 Foundation Systems ...... 8 4.3.1 Design Recommendations – Slab-on-Grade Foundation Systems ...... 9 4.3.2 Construction Considerations – Slab-on-Grade Foundation Systems ...... 10 4.3.3 Design Recommendations – Shallow Spread/Strip Footings ...... 11 4.3.4 Construction Considerations – Shallow Spread/Strip Footings ...... 11 4.4 Below Grade Excavation Considerations ...... 12 4.4.1 Temporary Groundwater Control ...... 13 4.4.2 Lateral Earth Pressures ...... 13 4.5 Foundation Construction Monitoring ...... 13 4.6 Pavements ...... 13 5.0 GENERAL COMMENTS ...... 17

APPENDIX A – FIELD EXPLORATION Exhibit A-1 Site Location Plan Exhibits A-2a, 2b, and 2c Boring Location Plans Exhibit A-3 Field Exploration Description Exhibit A-4 through A-7 Boring Logs

APPENDIX B – LABORATORY TESTING Exhibit B-1 Laboratory Testing

APPENDIX C – SUPPORTING DOCUMENTS Exhibit C-1 General Notes Exhibit C-2 Unified Soil Classification System

Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

EXECUTIVE SUMMARY

This geotechnical engineering report has been prepared for the proposed construction of additions to three water plants located in Conroe, Texas. Two test borings, designated as B-1 and B-2, were drilled to depths of about 30 feet below existing grade (grade at the time of our field exploration) for the proposed pump station building at Water Plant 6. Borings B-3 and B-4 where drilled to depths of about 30 feet for the proposed generator slabs at Water Plants 14 and 15.

Based on the information obtained from our subsurface exploration, the site can be developed for the proposed project. A summary of our findings and recommendations is provided below:

 The soils at the three water plants generally consisted of silty sand, silty clayey sand, and clayey sand, with layers of fat clay with varying amounts of sand in borings B-1 and B-2 (Water Plant 6) and poorly graded sand layers at borings B-3 and B-4 (Water Plants 14 and 15). Approximately 1 foot of clayey sand fill was observed at the surface in borings B-1 and B-2, and about 4 feet of clayey sand fill was observed below about ¼ inch of asphalt at the surface in boring B-3 (Water Plant 14).

 Groundwater was not observed in borings B-1 and B-3 during or upon completion of 1 drilling. Groundwater was observed in borings B-2 and B-4 at depths of about 17 /2 to 23 feet below existing grade during drilling and at depths of about 22 feet below grade after completion of drilling.

 The surface and near-surface soils at these sites included moisture-sensitive silty sands. These soils may become weak with elevated moisture contents, and present construction difficulties. Recommendations are provided in this report to help mitigate wet/soft subgrade conditions, if present at the time of construction.

 Shallow spread footings may be used to support the pump building and pipe within the trenches on the interior of the pump building at Water Plant 6.

 A conventionally-reinforced, monolithically-poured slab-on-grade foundation system may be utilized to support the generator slabs at these sites provided the subgrade is prepared as discussed in this report.

 A minimum 12-inch thick select fill pad should be placed under the proposed pump building floor slab and under the generator slabs. The select fill should extend a minimum of 3 feet beyond the edge of the proposed structures.

This summary should be used in conjunction with the entire report for design purposes. Details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled “5.0 GENERAL COMMENTS” should be read for an understanding of the report limitations.

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GEOTECHNICAL ENGINEERING REPORT CITY OF CONROE 2014 SURFACE WATER SYSTEM IMPROVEMENTS WATER PLANTS CONROE, TEXAS Project No. 97145017 August 6, 2014

1.0 INTRODUCTION

Terracon Consultants, Inc. (Terracon) is pleased to submit our geotechnical engineering report for proposed additions to three water plants as part of the City of Conroe 2014 Surface Water System Improvements project. A draft report was submitted for review on May 8, 2014. This project was formally authorized by Mr. Rafael Ortega, P.E., Vice President with Lockwood, Andrews & Newman, Inc. (LAN), through signature of Work Authorization No. 130-10292-003, dated March 7, 2014, to the Master Agreement between Terracon and LAN dated October 19, 2006. The project scope was performed in general accordance with Terracon Proposal No. P97140021 dated January 20, 2014.

The purpose of this geotechnical engineering report is to describe the subsurface conditions observed at the four test borings drilled for this project, analyze and evaluate the test data, and provide recommendations with respect to:

■ Site and subgrade preparation ■ Foundation design and construction ■ Pavement thickness and design guidelines

2.0 PROJECT INFORMATION

2.1 Project Description

Item Description Project location See Appendix A, Exhibit A-1, Site Location Plan. See Appendix A, Exhibits A-2a, 2b, and 2c, Boring Location Site layout Plans.

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Item Description ■ Water Plant 6 - Pump station building, either prefabricated metal or precast concrete, approximately 50 feet by 25 feet in size. Pipe trenches approximately 32 feet long, with an interior width of about 3.5 feet, will extend approximately 6 Proposed improvements feet below finished floor of the building. Associated portland cement concrete paving. ■ Water Plants 14 and 15- Generator slabs, approximately 20 feet by 10 feet in size.  Pump Building - Wall loads of approximately 2 to 3 kips per linear foot and floor slab pressure less than 125 pounds per Maximum loads (assumed) square foot (psf).  Generator Slabs – Unknown. Finished floor elevation (assumed) Within about one foot of existing grade.

 Pump Building – Shallow spread footings for building structure and pipe supports with grade supported floor slab Planned foundation system surrounding pipe trenches.  Generator pads - Conventionally-reinforced, monolithically poured slab-on-grade foundation systems

2.2 Site Description

Item Description

 Water Plant 6 – Westview Boulevard, just south of Loop 336 North.  Water Plant 14 – Longmire Road approximately 1¼ miles Site location north of FM 3083.  Water Plant 15 – Silver Springs Road just east of State Highway 75.

 Water Plant 6 and 15 – Grass. Current ground cover  Water Plant 14 – Grass and asphalt drive. Existing topography Relatively level.

3.0 SUBSURFACE CONDITIONS

3.1 Geology

The sites are located on the Willis Formation, the oldest formation of the Houston Group. The Willis Formation was deposited early in the Pleistocene epoch, during the Aftonian Interglacial Stage. It is fluviatile, consisting of sands, silts, and clays in approximately equal amounts. It is on the order of 200 ft thick in full section. The formation grades generally from coarse sands at its basal contact with the soils of the older Fleming Group to sandy clays near its contact with

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017 the overlying lower Lissie (Bently) Formation. Indurations of ferrous particles and siliceous gravel are frequent. Siliceous and ferrous compounds also serve as cementing agents in many of the sandy clay strata.

The clays are deeply weathered lateritic soils and have been highly overconsolidated, apparently by a process of desiccation. The sands are generally coarser and better graded than those of younger formations nearer the coast. The soils, both clays and sands, are therefore quite strong and are capable of supporting structural loadings without undue distress.

The coastal plain in this region has a complex tectonic geology, several major features of which are: Gulf Coastal geosyncline, salt domes, major sea level fluctuations during the glacial stages, subsidence and faulting activities. Most of these faulting activities have ceased for millions of years, but some are still active. A detailed geologic fault investigation and study of the site geology were beyond the scope of this study.

3.2 Typical Profile The particular subsurface stratigraphy, as evaluated from our field and laboratory programs, is shown in detail on the boring logs in Appendix A. The soils at the three water plants generally consisted of silty sand, silty clayey sand, and clayey sand, with layers of fat clay with varying amounts of sand in borings B-1 and B-2 (Water Plant 6) and poorly graded sand layers at borings B-3 and B-4 (Water Plants 14 and 15). Approximately 1 foot of clayey sand fill was observed at the surface in borings B-1 and B-2, and about 4 feet of clayey sand fill was observed below about ¼ inch of asphalt at the surface in boring B-3 (Water Plant 14).

Conditions observed at the boring locations are indicated on the Boring Logs. Stratification boundaries on the Boring Logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual.

Based on our field and laboratory programs, engineering values for the subsurface conditions at each water plant can be summarized as follows:

Subsurface Soils – Water Plant 6 (B-1 & B-2) Moisture Content vs. Undrained Description Plasticity Moisture Plastic Shear SPT Percentage Index Content Limit1 Strength2 N-Value3 of Fines4 (%) (%) (%) (tsf) (bpf) (%) Silty Sand NP5 4 to 8 ------7 to 17 14 to 17 Clayey Sand and 5 to 16 9 to 10 -5 to -1 --- 17 to 43 31 to 35 Silty Clayey Sand Sandy Fat Clay 28 to 43 17 to 24 -2 5,200 15 to 28 53 to 93 and Fat Clay

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Continued from Page 3 1. The difference between a soil sample’s in-situ moisture content and its corresponding plastic limit. 2. Based on unconfined compressive strength tests. 3. bpf = blows per foot. 4. Percent passing the No. 200 sieve. 5. NP = Non plastic. Based on visual classification.

Subsurface Soils – Water Plant 14 (B-3)

Moisture Undrained Description Plasticity Moisture Content vs. Shear SPT Percentage Index Content Plastic Limit1 Strength2 N-Value3 of Fines4 (%) (%) (%) (tsf) (bpf) (%) Clayey Sand Fill 19 7 -4 ------48 Silty Sand and Poorly Graded NP5 3 to 4 ------4 to 12 3 to 18 Sand Clayey Sand 10 to 17 9 to 13 -2 to +1 --- 14 to 25 27 to 40 1. The difference between a soil sample’s in-situ moisture content and its corresponding plastic limit. 2. Based on unconfined compressive strength tests. 3. bpf = blows per foot. 4. Percent passing the No. 200 sieve. 5. NP = Non plastic. Based on visual classification.

Subsurface Soils – Water Plant 15 (B-4) Moisture Content vs. Undrained Description Plasticity Moisture Plastic Shear SPT Percentage Index Content Limit1 Strength2 N-Value3 of Fines4 (%) (%) (%) (tsf) (bpf) (%) Silty Sand and Poorly Graded NP5 4 to 12 ------4 to 30 4 to 26 Sand Clayey Sand 20 13 +1 --- 19 to 31 26 1. The difference between a soil sample’s in-situ moisture content and its corresponding plastic limit. 2. Based on unconfined compressive strength tests. 3. bpf = blows per foot. 4. Percent passing the No. 200 sieve. 5. NP = Non plastic. Based on visual classification.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

3.3 Groundwater

Borings B-1 through B-4 were advanced using dry drilling techniques to their termination depths of approximately 30 feet below existing grade in an effort to evaluate groundwater conditions at the time of the field program. The observed groundwater measurements are summarized in the table below.

Summary of Short-term Groundwater Information Approximate Groundwater Depth (feet)1,2 Boring No. Boring Location During Dry Drilling End of Dry Drilling End of Day

B-1 Not Observed Not Observed -- Water Plant 6 B-2 23 22 22 B-3 Water Plant 14 Not Observed Not Observed -- B-4 Water Plant 15 17½ 10 --

1. Below existing grade at the time of our field activities. 2. Groundwater measurements are rounded to the nearest one-half foot.

These groundwater measurements are considered short-term, since the borings were open for a short time period. On a long-term basis, groundwater may be present at shallower depths. Additionally, groundwater will fluctuate seasonally with climatic changes and should be evaluated just prior to construction.

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

The following recommendations are based upon the data obtained in our field and laboratory programs, project information provided to us, and on our experience with similar subsurface and site conditions.

4.1 Geotechnical Considerations

The near-surface soils at these sites included moisture-sensitive silty sands and clayey sands. These soils may become weak with elevated moisture contents, presenting construction difficulties. The wet and weak surface soils may also become a hindrance to equipment access. In addition, it may be difficult to properly compact the soils sufficiently to place fill. If the subgrade is wet and/or soft at the time of construction, remedial efforts may be necessary for preparation of the surficial soils to create a working surface. Remedial efforts are discussed in the “4.2.2 Wet Weather/Soft Subgrade Considerations” section.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

4.2 Earthwork

Construction areas should be stripped of all vegetation, topsoil, existing asphalt, and other debris/unsuitable surface material. We understand that the new generators at Water Plants 14 and 15 will be constructed within the same area as the existing generators. Demolition of existing concrete slabs will be required prior to new construction. Special care should be exercised to demolish and remove the existing concrete slabs and any buried structures to help reduce disturbance of the subgrade and potential detrimental effects on construction of the proposed development at these sites. Shallow footings, grade beams, or other shallow buried obstructions should be removed and the excavation backfilled with properly placed and compacted select fill. Proper site drainage should be maintained during construction so that ponding of surface runoff does not occur and cause construction delays and/or inhibit site access.

Once final subgrade elevations have been achieved, the exposed subgrade should be carefully proofrolled with a 20-ton pneumatic roller or equivalent equipment, such as a fully loaded dump truck, to detect weak zones in the subgrade. Weak areas detected during proofrolling, as well as zones of fill containing organic matter and/or debris, should be removed and replaced with soils exhibiting similar classification, moisture content, and density as the adjacent in-situ soils. Proofrolling should be performed under the direct observation of the geotechnical engineer or his/her representative.

Subsequent to proofrolling, and just prior to placement of fill, the exposed subgrade within the construction areas should be evaluated for moisture and density. If the moisture and/or density do not meet the criteria described in the “4.2.1 Compaction Requirements” section for on-site soils, the subgrade should be scarified to a minimum depth of 6 inches, moisture adjusted and compacted to at least 95 percent of the Standard Effort (ASTM D 698) maximum dry density.

Select fill below the building and generator slabs should meet the following criteria.

Fill Type USCS Classification Acceptable Location for Placement

1 Must be used to construct the building floor and CL and/or SC Select fill generator slab fill pads and for all grade adjustments (10≤PI≤20) within the proposed construction areas. 1. CL and SC soils are described in ASTM D2487.

If blended or mixed soils are intended for use to construct the building and generator fill pads, Terracon should be contacted to provide additional recommendations. Blended or mixed soils do not occur naturally. These soils are a blend of sand and clay and will require mechanical mixing with a pulvimixer at the site. If these soils are not mixed thoroughly to break down the clay clods and blend-in the sand to produce a uniform soil matrix, the fill material may be

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017 detrimental to the slab performance. If blended soils are used, we recommend that additional samples of the blended soils, as well as the clay clods, be obtained prior to and during earthwork operations to evaluate if the blended soils can be used in lieu of select fill. The actual type and amount of mechanical mixing at the site will depend on the amount of clay and sand, and properties of the clay.

4.2.1 Compaction Requirements Item Description The fill soils should be placed on prepared surfaces in Fill Lift Thickness lifts not to exceed 8 inches loose measure, with compacted thickness not to exceed 6 inches.

 The select fill should be compacted to at least 95 percent of the material’s Standard Effort (ASTM D Compaction Requirements 698) maximum dry density.  The select-fill should be moisture adjusted to within 2 percent of the material’s optimum moisture content.

Prior to any filling operations, samples of the proposed borrow and on-site materials should be obtained for laboratory moisture-density testing. The tests will provide a basis for evaluation of fill compaction by in-place density testing. A qualified soil technician should perform sufficient in- place density tests during the filling operations to evaluate that proper levels of compaction, including dry unit weight and moisture content, are being attained.

4.2.2 Wet Weather/Soft Subgrade Considerations The recommended compaction may be difficult to achieve in the on-site moisture-sensitive silty sands. In addition, construction operations may encounter difficulties due to the surficial soils becoming a general hindrance to equipment as a result of rutting and/or pumping of the soil surface, especially during and soon after periods of wet weather. This condition is primarily due to their lack of cohesion (low clay content) and little to no confining pressure near the ground surface. If the subgrade cannot be adequately compacted to the minimum densities as described above, one of the following methods should be used to improve the soils: 1) removal and replacement with select fill, 2) chemical treatment of the soil to dry the subgrade, or 3) drying by natural means if the schedule allows.

Based on our experience with similar soils, chemical treatment is the most efficient and effective method to increase the supporting value of wet and soft subgrade. Chemical treatment may be necessary to depths of up to approximately 2 to 3 feet of the near-surface soils or greater depths, depending on the condition of the soils at the time of construction. We suggest that a contingency or allowance be included in the construction budget for chemical treatment of the soils using a lime-flyash mixture to produce drying and to improve the condition of the soil if the surficial soils are wet and/or soft at the time of construction. Terracon should be contacted for additional recommendations if chemical treatment is planned due to wet/soft subgrade.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

4.2.3 Grading and Drainage All grades must provide effective drainage away from the building area during and after construction. Water permitted to pond next to the building can result in distress in the building. These greater movements can result in unacceptable differential floor slab movements, cracked slabs and walls, and roof leaks. Building slab and foundation performances described in this report are based on effective drainage for the life of the structure and cannot be relied upon if effective drainage is not maintained.

Exposed ground should be sloped away from the building for at least 10 feet beyond the perimeter of the building. After building construction and landscaping, we recommend verifying final grades to document that effective drainage has been achieved. Grades around the building should also be periodically inspected and adjusted as necessary, as part of the structure's maintenance program.

Planters located within 10 feet of the building should be self-contained to prevent water accessing the building and pavement subgrade soils. Locate sprinkler mains and spray heads a minimum of 5 feet away from the building lines. Low-volume, drip-style landscaped irrigation should not be used near the building. Collect roof runoff in drains or gutters. Discharge roof drains and downspouts onto pavements and flatworks which slope away from the building or extend down spouts a minimum of 10 feet away from the structure.

Flatworks and pavements will be subject to post construction movement. Maximum grades practical should be used for paving and flatwork to prevent water from ponding. Allowances in final grades should also consider post-construction movement of flatwork, particularly if such movement would be critical. Where paving or flatwork abuts the structure, effectively seal and maintain joints to prevent surface water infiltration.

Utility trenches are a common source of water infiltration and migration. All utility trenches that penetrate beneath the building should be effectively sealed to restrict water intrusion and flow through the trenches that could migrate below the building. We recommend constructing an effective clay “trench plug” that extends at least 5 feet out from the face of the building exterior. The plug material should consist of lean clay with an Atterberg plasticity index between 15 and 25, compacted at a water content at or above the soils optimum water content. The clay fill should be placed to completely surround the utility line and be compacted in accordance with recommendations in this report.

4.3 Foundation Systems

Based upon the subsurface conditions observed during our field and laboratory programs, a foundation system consisting of a conventionally-reinforced, monolithically poured slab-on- grade may be utilized to support the pump station building and generators provided the

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017 subgrade is prepared as discussed in this report. The pump building and below grade pipe supports and piping at Water Plant 6 are planned to be supported on shallow spread or strip footings. Recommendations for these types of foundation systems are provided in the following sections, along with other geotechnical considerations for this project.

4.3.1 Design Recommendations – Slab-on-Grade Foundation Systems Planned finished grades at the sites were not available at the time of this report. Once finished grades have been established, Terracon should be notified to review and/or modify our recommendations given in this subsection.

Based on the information developed from our field and laboratory programs and using TxDOT Method TEX-124-E, we have estimated a potential vertical rise (PVR) of about one inch for the existing subgrade conditions at the three water plant sites.

We recommend that a minimum of 12 inches of properly placed and compacted select fill material be constructed below the building and generator slabs to provide uniform support and to provide a more stable working surface. The fill pads should extend a minimum of 3 feet beyond the edge of the proposed building and generator slabs. The final exterior grade adjacent to the structures should be sloped to promote effective drainage away from the structures.

Select fill should be utilized for all grade adjustments within the proposed building and generator areas. The subgrade and select fill soils should be prepared as outlined in the “4.2 Earthwork” section which contains material and placement requirements for select fill, as well as other subgrade preparation recommendations.

The slab-on-grade foundations at the water plants may be designed using the following parameters provided that the building subgrade is prepared as discussed above:

Description Design Parameters

Select fill building pad Minimum thickness of 12 inches

Estimated PVR About one inch or less

Climatic rating 25

Design Plasticity Index1 20

Soil support index1 0.96

Minimum perimeter grade beam 18 inches below exterior grade embedment depth

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Continued from Page 9

Dead Load Plus Sustained Live Load: 1,200 psf Allowable bearing capacity Total Net Load: 1,800 psf

1. Design parameters based on a minimum 12-inch thick select fill pad.

The parameters indicated for the above design conditions are based on criteria published by the Building Research Advisory Board (B.R.A.B.). The B.R.A.B. method is essentially an empirical design technique and the parameters provided are based on our interpretation of the project soil borings and criteria published in the B.R.A.B. design manual.

The slab-on-grade foundation systems should be designed to tolerate the anticipated soil movement and provide satisfactory support to the proposed structures. The foundation should have adequate exterior and interior grade beams to provide sufficient rigidity to the foundation system such that the slab deflections that result are considered tolerable to the supported structures. Grade beams may be thickened and widened at interior column locations to serve as spread footings at areas of concentrated loadings. The minimum perimeter grade beam depth recommendation provided above is to reduce surface water migration below the foundation elements and to develop proper end bearing and is not based on structural considerations.

Post construction settlements for the described slab-on-grade foundation system should be one inch or less, provided that the subgrade soils are prepared as outlined herein and that the select fill is properly placed and compacted in accordance with the recommendations contained in this report. Settlement response of the foundation system is expected to be influenced more by the quality of construction and fill placement than by soil-structure interaction.

4.3.2 Construction Considerations – Slab-on-Grade Foundation Systems Excavations for the slab-on-grade foundation system should be performed with equipment capable of providing a relatively clean bearing area. The bottom 6 inches of the foundation excavations should be performed using a smooth-mouthed excavation bucket or hand labor. The excavations should be neatly excavated and properly formed. Debris in the bottom of the excavations should be removed prior to steel placement. Water should not be allowed to infiltrate foundation excavations. To reduce the potential for groundwater seepage into the excavations and to minimize disturbance to the bearing area, we recommend that steel and concrete be placed as soon as possible after the excavations are completed and properly cleaned. The bearing surface of the foundation should be evaluated upon completion of the excavation and immediately prior to placing concrete.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

4.3.3 Design Recommendations – Shallow Spread/Strip Footings Description Design Parameters

Minimum embedment below existing grade1 6 feet Net allowable bearing pressure (individual Net dead plus sustained live load – 3,000 psf footings and strip footings)2 Net total load – 4,500 psf Approximate total settlement3 Approximately one inch

Estimated differential settlement4 Approximately ½ of total settlement

Allowable passive pressure5 1,500 psf

Allowable frictional resistance6 300 psf Foundation Weight (150 pcf) & Uplift resistance7 Soil Weight (120 pcf) 1. The footings should bear upon undisturbed native clayey sand or silty clayey sand soils. 2. Strip footing is defined as a footing at least twice as long as it is wide. Net total load includes temporary live load in addition to dead plus sustained live load. 3. Provided proper construction practices are followed. A clear distance between footings of one footing size of the larger of the two footings should not produce overlapping stress distributions and would essentially behave as independent foundations. 4. Differential settlements may result from variances in subsurface conditions, loading conditions and construction procedures. The settlement response of the footings will be more dependent upon the quality of construction than upon the response of the subgrade to the foundation loads. 5. Lateral loads transmitted to the shallow spread footings will be resisted by a combination of soil- concrete friction on the base of the footing and passive pressure on the sides of the footing. The passive pressure along the exterior face of the footings should be neglected within the upper 3 feet due to surface effects unless pavement and/or flatwork is provided up to the edge of the structure. 6. To be utilized on the base of the footings. 7. Structural uplift loads on the shallow footings may be resisted by the weight of the foundation plus the weight of any soil directly above the foundation. The ultimate uplift capacity of shallow footings should be reduced by an appropriate factor of safety to compute allowable uplift capacity.

4.3.4 Construction Considerations – Shallow Spread Footings Excavations for the shallow spread footings should be performed with equipment capable of providing a relatively clean bearing area. The bottom 6 inches of the foundation excavations should be performed using a smooth-mouthed excavation bucket or hand labor. The excavations should be neatly excavated and properly formed. Debris in the bottom of the excavations should be removed prior to steel placement. Water should not be allowed to infiltrate foundation excavations. To reduce the potential for groundwater seepage into the excavations and to minimize disturbance to the bearing area, we recommend that steel and concrete be placed as soon as possible after the excavations are completed and properly cleaned. Excavations should not be left open overnight. The bearing surface should be evaluated immediately prior to placing concrete.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

4.4 Below Grade Excavation Considerations

Pipe trenches within the pump building at Water Plant 6 will extend to depths of about 6 feet below finished grade of the building. Deep excavations will also be required to construct the spread footings to support the building. The sides of the below-grade walls may either be sloped or formed with vertical cuts. For vertical cut excavations greater than 5 feet in depth, the excavations will require the use of shoring, bracing or some form of retention to prevent sloughing and caving of the soil into the excavation.

Bracing for vertical excavation walls should be designed to resist a uniform lateral earth pressure of at least 36H in psf, where H is the depth of the excavation in feet. Additional lateral pressure, due to surcharge loads along the perimeter of the excavation, should be considered by adding a lateral pressure of 50 percent of the surcharge pressure.

OSHA standards provide recommendations for the design of temporary sloped excavations with a depth more than 5 feet and less than 20 feet. The OSHA standards provide maximum allowable slopes contingent on three designated soil types: Type A, Type B, and Type C. According to OSHA standards, temporary sloped excavations should be no steeper than 0.75- horizontal on 1-vertical (0.75H:1V) for Type A soils, 1H:1V for Type B soils, and 1.5H:1V for Type C soils. The surface soils should be protected from deterioration and weathering if they are left open for significant periods of time.

The contractor should use a trench box or shoring and bracing as necessary to maintain a safe and clean excavation which meets with the Occupational Safety and Health Administration (OSHA) requirements. Excavations must be performed and inspected under the supervision of a contractor designated Competent Person. The Competent Person, as defined by the OSHA Standard, 29 CFR Part 1926.650 to .652, Subpart P – Excavations, must evaluate the excavations at the time of construction activity to safeguard workers.

Excavations should be performed with equipment capable of providing a relatively clean bearing area. Excavating equipment should not disturb the soil beneath the design excavation bottom and should not leave large amounts of loose soil in the excavation.

As a safety measure, no equipment should be operated within 5 feet of the edge of the excavation and no materials should be stockpiled within 10 feet of the excavation. Excavations should not approach closer than 10 feet from existing structures/facilities without some form of protection for the facilities. Proper berming or ditching should be performed to divert any surface runoff away from the excavation.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

4.4.1 Temporary Groundwater Control Groundwater was not observed in boring B-1 during or on completion of drilling. Groundwater was initially observed during dry drilling at boring B-2 at a depth of about 23 feet below existing grade during drilling, and was observed at a depth of about 22 feet at the end of the day the boring was drilled. Groundwater is not anticipated in the excavations for the pipe trenches and spread footings to the planned depth of about 6 to 8 feet below finished floor of the building. Minor seepage could occur from perched water trapped in surficial soil. Minor seepage can be handled by pumping.

Water-proofing may be applied to the exterior walls of the pipe trenches and floor slab in order to reduce the potential for moisture on the interior of the below-grade portion of the structure.

4.4.2 Lateral Earth Pressures Soil around the below-grade trench will impose active to at-rest earth pressures against the embedded walls. Design lateral earth pressures for backfill are estimated to be equivalent to a fluid pressure of 50 pcf for clean sand backfill and 90 pcf for backfill consisting of on-site clayey soils. These pressures do not include hydrostatic pressures or surcharge forces imposed by construction or vehicular loading. The lateral pressure produced by a surcharge may be computed as 50 percent of the vertical surcharge pressure applied as a constant pressure over the full depth of the buried structure. A minimum 2-foot thick compacted clay seal should be placed at the top of sand backfill to reduce the amount of infiltration of surface water.

4.5 Foundation Construction Monitoring

The performance of the foundation systems for the proposed structures will be highly dependent upon the quality of construction. Thus, we recommend that the subgrade preparation, fill compaction, and foundation installation be monitored full time by an experienced Terracon soil technician under the direction of our geotechnical engineer. During foundation installation, the base of the foundations should be monitored to evaluate the condition of the subgrade. We would be pleased to develop a plan for compaction and foundation installation monitoring to be incorporated in the overall quality control program.

4.6 Pavements

We understand that new paving will be constructed at Water Plant No. 6. Based on the subsurface conditions observed, we anticipate that the pavement subgrade will generally consist of the on-site clayey sand or silty sand soils. We recommend that the top 6 inches of the finished subgrade soils directly beneath the pavements be chemically treated with a mixture of lime and flyash. Chemical treatment will increase the supporting value of the subgrade and decrease the effect of moisture on subgrade soils. This 6 inches of treatment is a required part of the pavement design and is not a part of site and subgrade preparation for wet/soft subgrade conditions.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Detailed traffic loads and frequencies were not available. However, we anticipate that traffic will consist primarily of ½-ton to 2-ton pick-up trucks, with occasional heavy trucks for material deliveries.

Tabulated in the following table are the assumed traffic frequencies and loads used to design pavement sections for this project.

Pavement Traffic Description Area Design Index Medium to light traffic (Similar to DI-1 including not Driveways over 50 loaded two-axle trucks or lightly-loaded larger DI-2 (Light Duty) vehicles per day. No regular use by heavily-loaded trucks with three or more axles.) (EAL = 6-20) Driveways Medium traffic (Including not over 300 heavily-loaded and Truck Traffic two-axle trucks plus lightly-loaded trucks with three or DI-3 Areas (Medium more axles and no more than 30 heavily-loaded trucks Duty) with more than three axles per day.) (EAL = 21-75) 1 Equivalent daily 18-kip single-axle load applications.

Listed below are pavement component thicknesses, which may be used as a guide for pavement systems at the site for the traffic classifications stated herein. These systems were derived based on general characterization of the subgrade. Specific testing (such as CBR, resilient modulus, etc.) was not performed for this project to evaluate the support characteristics of the subgrade.

Rigid Pavement System Material Thickness, Inches Component DI-2 DI-3

Reinforced Concrete 6.0 7.0 Treated Subgrade 6.0 6.0

We recommend that waste dumpster areas be constructed of at least 7 inches of reinforced concrete pavement. The concrete pad areas should be designed so that the vehicle wheels of the collection truck are supported on the concrete while the dumpster is being lifted to support the large wheel loading imposed during waste collection.

Presented below are our recommended material requirements for the various pavement sections.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Reinforced Concrete Pavement – The materials and properties of reinforced concrete pavement shall meet applicable requirements in the ACI Manual of Concrete Practice. The portland cement concrete mix should have a minimum 28-day compressive strength of 3,500 psi.

Reinforcing Steel – ACI recommendations indicate that distributed steel reinforcement is not necessary when the pavement is properly jointed to form short panel lengths that will help reduce intermediate cracking. Provided the concrete pavement is designed and constructed as stated herein, the installation of reinforcing steel is optional and should be evaluated by the design team. Proper layout and installation of the joints within the pavement is critical to help control intermediate cracking.

If reinforcing steel is planned to be utilized in the concrete pavement by the design team, the following amount of reinforcing steel should be used as a guideline:

DI-1: #3 bars spaced at 18 inches or #4 bars spaced at 24 inches on centers in both directions. DI-2: #3 bars spaced at 12 inches or #4 bars spaced at 18 inches on centers in both directions. DI-3: #4 bars spaced at 18 inches on centers in both directions.

Control Joint Spacing – ACI recommendations indicate that control joints should be spaced at a maximum spacing of 30 times the thickness of the pavement for unreinforced parking lot pavements. Furthermore, ACI recommends a maximum control joint spacing of 12.5 feet for 5- inch pavements and a maximum control joint spacing of 15 feet for 6-inch or thicker pavements. Sawcut control joints should be cut within 4 to 12 hours of concrete placement to help control the formation of plastic shrinkage cracks as the concrete cures. The depth of the joint should be at least one-quarter of the slab depth when using a conventional saw or one inch when using early entry saws. The width of the cut should be in accordance with the joint sealant manufacturer recommendations.

Expansion Joint Spacing – ACI recommendations indicate that regularly spaced expansion joints may be deleted from concrete pavements. Therefore, the installation of expansion joints is optional and should be evaluated by the design team.

Construction Joints – When concrete is planned to be placed at different times, we recommend the use of a construction joint between paving areas. The construction joint should consist of a butt joint (not a keyway joint).

Concrete Curing Compound – A concrete curing compound, such as a Type 2 membrane curing compound conforming to TxDOT DMS-4650, “Hydraulic Cement Concrete Curing Materials and Evaporation Retardants” or equivalent, should be applied to the concrete surface immediately after placement of the concrete in accordance with TxDOT 2004 Standard Specifications Item 360.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Dowels at Expansion Joints – The dowels at expansion joints should be spaced at 12-inch centers and consist of the following: DI-1: 5/8-inch diameter, 12-inches long with 5-inch embedment DI-2: 3/4-inch diameter, 14-inches long with 6-inch embedment DI-3: 7/8-inch diameter, 14-inches long with 6-inch embedment

Lime-Flyash Treated Subgrade – The on-site clayey sand and/or silty sand soils should be treated with lime-flyash in accordance with TxDOT 2004 Standard Specifications Item 265. Based on the classification test results, we recommend about 2 percent lime and 8 percent flyash by dry weight be used for estimating and planning. The percentages are given as application by dry weight and are typically equivalent to about 10 pounds of lime and 40 pounds of flyash per square yard per 6-inch depth. Lime-flyash is also available pre-mixed, typically in percentages of 20 percent lime and 80 percent flyash. These pre-mixed products may be used if preferred at a rate of 50 pounds per square yard per 6-inch depth. The actual quantity of the lime and flyash should be determined at the time of construction once the pavement subgrade is exposed. The subgrade should be treated in accordance with TxDOT Standard Specification Item 265 for lime-flyash treated subgrade. The subgrade should be compacted to at least 95 percent of the Standard Effort (ASTM D 698) maximum dry density at a moisture content within 2 percent of the optimum moisture content.

Preferably, traffic should be kept off the treated subgrade for about 7 days to facilitate curing of the soil-chemical mixture. In addition, the subgrade is not suitable for heavy construction traffic prior to paving.

Post-construction subgrade movements and some cracking of pavements are not uncommon for subgrade conditions such as those observed at this site. Although chemical treatment will help to reduce such movement/cracking, this movement/cracking cannot be economically eliminated.

Underground utility trenches may extend below the paving. Utility trenches should be backfilled with cement stabilized sand compacted to at least 95 percent of the maximum dry density.

Related civil design factors such as subgrade drainage, shoulder support, cross-sectional configurations, surface elevations and environmental factors which will significantly affect the service life must be included in the preparation of the construction drawings and specifications. Normal periodic maintenance will be required.

Long-term pavement performance will be dependent upon several factors, including maintaining subgrade moisture levels and providing for preventative maintenance. The following recommendations should be implemented to help promote long-term pavement performance:

■ Site grading should be designed to drain away from the pavements, preferably at a minimum grade of 2 percent

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

■ The subgrade and the pavement surface should be designed to promote proper surface drainage, preferably at a minimum grade of 2 percent ■ Joint sealant should be installed and cracks should be sealed immediately ■ Curbs should be extended into the treated subgrade for a depth of at least 4 inches to help reduce moisture migration into the subgrade soils beneath the pavement section ■ Compacted, low permeability clayey backfill should be placed against the exterior side of the curb and gutter.

Preventative maintenance should be planned and provided for the pavements at this site. Preventative maintenance activities are intended to slow the rate of pavement deterioration, and consist of both localized maintenance (e.g. crack and joint sealing and patching) and global maintenance (e.g. surface sealing). Prior to implementing any maintenance, additional engineering observations are recommended to determine the type and extent of preventative maintenance.

5.0 GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation installation, and other earth-related construction phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated location and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other services should be undertaken.

For any excavation construction activities at this site, all Occupational Safety and Health Administration (OSHA) guidelines and directives should be followed by the Contractor during construction to insure a safe working environment. In regards to worker safety, OSHA Safety and Health Standards require the protection of workers from excavation instability in trench situations.

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Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

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APPENDIX A FIELD EXPLORATION

SITE LOCATION

5,500' 0 2,750' 5,500'

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES SCALE IN FEET

Project Mng. Project No. SB 97145017 SITE LOCATION PLAN Exhibit Drawn By: Scale: City of Conroe SB AS SHOWN Checked By: File No: Consulting Engineers & Scientists 2014 Surface Water System Improvements BSH 97145017 Water Plants A-1 Approved By: Date: 11133 I-45 South, Building T Conroe, Texas 77302 BSH 4/29/2014 PH. (936) 539-1384 FAX. (936) 539-9622 Conroe, Texas N

B-1

B-2

LEGEND 40' 0 20' 40'

SOIL BORING LOCATIONS SCALE IN FEET DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES

Project Mng. Project No. SB 97145017 BORING LOCATION PLAN Exhibit Drawn By: Scale: City of Conroe SB AS SHOWN Checked By: File No: Consulting Engineers & Scientists 2014 Surface Water System Improvements BSH 97145017 Water Plant 6 A-2a Approved By: Date: 11133 I-45 South, Building T Conroe, Texas 77302 BSH 4/29/2014 PH. (936) 539-1384 FAX. (936) 539-9622 Conroe, Texas N

Longmire Road

B-3

LEGEND 30' 0 15' 30'

SOIL BORING LOCATIONS SCALE IN FEET DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES

Project Mng. Project No. SB 97145017 BORING LOCATION PLAN Exhibit Drawn By: Scale: City of Conroe SB AS SHOWN Checked By: File No: Consulting Engineers & Scientists 2014 Surface Water System Improvements BSH 97145017 Water Plant 14 A-2b Approved By: Date: 11133 I-45 South, Building T Conroe, Texas 77302 BSH 4/29/2014 PH. (936) 539-1384 FAX. (936) 539-9622 Conroe, Texas N

Silver Springs Road

B-4

LEGEND 50' 0 25' 50'

SOIL BORING LOCATIONS SCALE IN FEET DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES

Project Mng. Project No. SB 97145017 BORING LOCATION PLAN Exhibit Drawn By: Scale: City of Conroe SB AS SHOWN Checked By: File No: Consulting Engineers & Scientists 2014 Surface Water System Improvements BSH 97145017 Water Plant 15 A-2c Approved By: Date: 11133 I-45 South, Building T Conroe, Texas 77302 BSH 4/29/2014 PH. (936) 539-1384 FAX. (936) 539-9622 Conroe, Texas Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Field Exploration Description

Subsurface conditions were evaluated by drilling four test borings for these projects. Borings B-1 and B-2 were drilled to depths of about 30 feet below existing grade (grade at the time of our field exploration) for the proposed pump station building at Water Plant 6. Borings B-3 and B-4 were drilled to depths of about 30 feet for the proposed generator slabs at Water Plants 14 and 15. The borings were drilled using track-mounted drilling equipment at the approximate locations shown on the Boring Location Plans, Exhibits A-2a, 2b, and 2c. The borings were located in the field by Terracon by measuring distances from existing site features shown on drawings provided by the Client. Boring depths were measured from existing grade at the time of our field program. Upon completion of our field program, the borings were backfilled with soil cuttings.

The Boring Logs, presenting the subsurface soil descriptions, type of sampling used, and additional field data, are presented on Exhibits A-4 through A-7. The General Notes, which define the terms used on the logs, are presented on Exhibit C-1 of Appendix C. The Unified Soil Classification System is presented on Exhibit C-2 of Appendix C.

Cohesive soil samples were generally recovered using open-tube samplers. Hand penetrometer tests were performed on samples of cohesive soils to serve as a general measure of consistency.

Granular soils and soils for which good quality open-tube samples could not be recovered were generally sampled by means of the Standard Penetration Test (SPT). This test consists of measuring the number of blows required for a 140-pound hammer free falling 30 inches to drive a standard split-spoon sampler 12 inches into the subsurface material after being seated 6 inches. This blow count or SPT N-value is used to evaluate the stratum. Three soil samples were obtained using an open tube sampler.

A CME automatic SPT hammer was used in advancing the split-spoon sampler for the borings drilled at this site. A greater efficiency is typically achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. Published correlations between the SPT N-values and soil properties are based on the lower efficiency cathead and rope method. The higher efficiency of an automatic SPT hammer affects the SPT N-value by increasing the penetration per hammer blow over what would be obtained using the cathead and rope method. The effect of the automatic hammer efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

Samples were removed from samplers in the field, visually classified, and appropriately sealed in sample containers to preserve their in-situ moisture contents. Samples were returned to our laboratory in Conroe, Texas.

Samples not tested in the laboratory will be stored for a period of 30 days subsequent to submittal of this report and will be discarded after this period, unless we are notified otherwise.

Exhibit A-3 BORING LOG NO. B-1 Page 1 of 1 PROJECT: City of Conroe 2014 Surface CLIENT: Lockwood Andrews & Newnam, Inc. Water System Improvements Houston, Texas SITE: Water Plant 6 Conroe, Texas ATTERBERG LOCATION See Exhibit A-2 STRENGTH TEST LIMITS

LL-PL-PI WATER (tsf) RESULTS DRY UNIT DEPTH (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG CONTENT (%) WATER LEVEL TEST TYPE STRENGTH STRAIN (%) SAMPLE TYPE OBSERVATIONS PERCENT FINES

DEPTH COMPRESSIVE CLAYEY SAND (SC), with gravel, tan and gray, medium 1.0 dense 6-5-10 6 25 SILTY SAND (SM), light gray, medium dense N=15

6-5-6 N=11 light gray and tan, loose, 4 to 6 feet 5 3-3-5 6.0 N=8 SILTY CLAYEY SAND (SC-SM), tan, light gray, and reddish-brown, medium dense to dense 5-6-11 9 19-14-5 31 N=17

5-17-26 N=43 10 8-12-16 12.0 N=28 SANDY FAT CLAY (CH), light gray and reddish-brown, very stiff 7-11-17 17 62-19-43 53 N=28 15

17.0 CLAYEY SAND (SC), tan, light gray, and reddish-brown, medium dense 6-11-14 N=25 20

22.0 FAT CLAY (CH), light gray, reddish-brown, and tan, hard

4.0 (HP) 5.21 4.6 24 99 54-26-28 93 25

4.5 (HP) 30.0 Boring Terminated at 30 Feet 30

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

Advancement Method: See Exhibit A-3 for description of field Notes: Dry Auger to 30 feet. procedures. See Appendix B for description of laboratory procedures and additional data (if any). Abandonment Method: See Appendix C for explanation of symbols and Boring backfilled with soil cuttings upon completion. abbreviations.

WATER LEVEL OBSERVATIONS Boring Started: 3/26/2014 Boring Completed: 3/26/2014 No free water observed Drill Rig: Track Driller: Terracon 11133 I-45 South, Bldg. T Conroe, Texas Project No.: 97145017 Exhibit: A-4 THIS BORING LOG IS NOT VALID SEPARATED IF FROM ORIGINAL REPORT. WELL GEO SMART PLANT LOG-NO 97145017.WATER 6.GPJ BORING LOG NO. B-2 Page 1 of 1 PROJECT: City of Conroe 2014 Surface CLIENT: Lockwood Andrews & Newnam, Inc. Water System Improvements Houston, Texas SITE: Water Plant 6 Conroe, Texas ATTERBERG LOCATION See Exhibit A-2 STRENGTH TEST LIMITS

LL-PL-PI WATER (tsf) RESULTS DRY UNIT DEPTH (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG CONTENT (%) WATER LEVEL TEST TYPE STRENGTH STRAIN (%) SAMPLE TYPE OBSERVATIONS PERCENT FINES

DEPTH COMPRESSIVE CLAYEY SAND (SC), tan and gray, medium dense 1.0 3-3-7 SILTY SAND (SM), brown, medium dense N=10

5-6-7 4 17 N=13 loose, 4 to 6 feet 5 2-4-3 6.0 N=7 CLAYEY SAND (SC), light gray, tan, and reddish-brown, medium dense to dense 10-14-22 N=36 medium dense, 8 to 10 feet 9-11-13 10 27-11-16 35 N=24 10 10-14-25 N=39

12-19-24 15.0 N=43 SILTY SAND (SM), light gray and tan, medium dense 15

7-8-9 8 NP 14 N=17 20 21.0 SANDY FAT CLAY (CH), light gray and tan, very stiff

4-6-12 N=18 25

3-4-11 18 56-20-36 57 30.0 N=15 Boring Terminated at 30 Feet 30

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 3/26/2014 Boring Completed: 3/26/2014 23 ft While Drilling Drill Rig: Track Driller: Terracon 22 ft at End of Boring 11133 I-45 South, Bldg. T Conroe, Texas Project No.: 97145017 Exhibit: A-5

THIS BORING LOG IS NOT VALID SEPARATED IF FROM ORIGINAL REPORT. WELL GEO SMART PLANT LOG-NO 97145017.WATER 6.GPJ 22 ft at End of Day BORING LOG NO. B-3 Page 1 of 1 PROJECT: City of Conroe 2014 Surface CLIENT: Lockwood Andrews & Newnam, Inc. Water System Improvements Houston, Texas SITE: Water Plant 14 Conroe, Texas ATTERBERG LOCATION See Exhibit A-2 STRENGTH TEST LIMITS

LL-PL-PI WATER (tsf) RESULTS DRY UNIT DEPTH (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG CONTENT (%) WATER LEVEL TEST TYPE STRENGTH STRAIN (%) SAMPLE TYPE OBSERVATIONS PERCENT FINES

DEPTH COMPRESSIVE 0.3 ASPHALT, 1/4 inch CLAYEY SAND (SC), light gray 7 30-11-19 48

reddish-brown and gray, stiff, 2 to 4 feet 2.0 (HP) 4.0 SILTY SAND (SM), brown and light gray, loose 2-1-3 5 4 18 N=4

2-2-3 8.0 N=5 CLAYEY SAND (SC), reddish-brown and light gray, medium dense to dense 2-5-9 13 29-12-17 40 N=14 10 9-16-14 N=30

9-10-15 9 21-11-10 27 N=25 15 16.0 POORLY GRADED SAND (SP), trace gravel, tan and light gray, medium dense

5-6-5 N=11 20

3-6-6 3 3 N=12 25

loose, below 28 feet 3-4-5 30.0 N=9 Boring Terminated at 30 Feet 30

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 3/26/2014 Boring Completed: 3/26/2014 No free water observed Drill Rig: Track Driller: Terracon 11133 I-45 South, Bldg. T Conroe, Texas Project No.: 97145017 Exhibit: A-6 THIS BORING LOG IS NOT VALID SEPARATED IF FROM ORIGINAL REPORT. WELL GEO SMART PLANT LOG-NO 97145017.WATER 14.GPJ BORING LOG NO. B-4 Page 1 of 1 PROJECT: City of Conroe 2014 Surface CLIENT: Lockwood Andrews & Newnam, Inc. Water System Improvements Houston, Texas SITE: Water Plant 15 Conroe, Texas ATTERBERG LOCATION See Exhibit A-2 STRENGTH TEST LIMITS

LL-PL-PI WATER (tsf) RESULTS DRY UNIT DEPTH (Ft.) FIELD TEST WEIGHT (pcf) GRAPHIC LOG CONTENT (%) WATER LEVEL TEST TYPE STRENGTH STRAIN (%) SAMPLE TYPE OBSERVATIONS PERCENT FINES

DEPTH COMPRESSIVE SILTY SAND (SM), gray, medium dense 2-9-13 4 15 N=22

5-8-8 N=16 light gray and reddish-brown, loose, 4 to 6 feet 2-4-3 5 10 NP 26 6.0 N=7 CLAYEY SAND (SC), light gray and tan, medium dense 4-9-10 N=19

5-11-12 13 32-12-20 26 N=23 dense, 10 to 12 feet 10 7-16-15 12.0 N=31 SILTY SAND (SM), light gray and tan, dense

6-16-14 11 NP 16 N=30 15

17.0 POORLY GRADED SAND (SP), trace gravel, tan, medium dense 7-11-12 N=23 20

1-2-9 12 4 N=11 25

loose, below 28 feet 1-2-2 30.0 N=4 Boring Terminated at 30 Feet 30

Stratification lines are approximate. In-situ, the transition may be gradual. Hammer Type: Automatic

WATER LEVEL OBSERVATIONS Boring Started: 3/26/2014 Boring Completed: 3/26/2014 17.5 ft While Drilling Drill Rig: Track Driller: Terracon 10 ft at End of Boring 11133 I-45 South, Bldg. T Conroe, Texas Project No.: 97145017 Exhibit: A-7 THIS BORING LOG IS NOT VALID SEPARATED IF FROM ORIGINAL REPORT. WELL GEO SMART PLANT LOG-NO 97145017.WATER 15.GPJ

APPENDIX B LABORATORY TESTING

Geotechnical Engineering Report City of Conroe – Water Plants ■ Conroe, Texas August 6, 2014 ■ Terracon Project No. 97145017

Laboratory Testing Description

Soil samples were tested in the laboratory to measure their dry unit weight and water content. Unconfined compression tests were performed on selected samples and a calibrated hand penetrometer was used to estimate the approximate unconfined compressive strength of some cohesive samples. The calibrated hand penetrometer values have been correlated with unconfined compression tests and provide a better estimate of soil consistency than visual examination alone. Selected samples were also classified using the results of Atterberg Limits and grain size analysis testing. The test results are provided on the Boring Logs included in Appendix A and in the “3.2 Typical Profile” section of this report.

Descriptive classifications of the soils indicated on the Boring Logs are in general accordance with the General Notes and the Unified Soil Classification System included in Appendix C. Also shown are estimated Unified Soil Classification Symbols. A brief description of this classification system is attached to this report. Classification of the soil samples was generally determined by visual manual procedures.

Exhibit B-1

APPENDIX C SUPPORTING DOCUMENTS

GENERAL NOTES DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

Water Initially (HP) Hand Penetrometer Encountered Water Level After a (T) Torvane Auger Split Spoon Specified Period of Time

Water Level After a Specified Period of Time (b/f) Standard Penetration Test (blows per foot) Shelby Tube Macro Core Water levels indicated on the soil boring (PID) Photo-Ionization Detector logs are the levels measured in the borehole at the times indicated. (OVA) Organic Vapor Analyzer

SAMPLING Groundwater level variations will occur Ring Sampler Rock Core over time. In low permeability soils, FIELD TESTS WATER LEVEL accurate determination of groundwater levels is not possible with short term water level observations. Grab Sample No Recovery

DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

LOCATION AND ELEVATION NOTES Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area.

RELATIVE DENSITY OF COARSE-GRAINED SOILS CONSISTENCY OF FINE-GRAINED SOILS (More than 50% retained on No. 200 sieve.) (50% or more passing the No. 200 sieve.) Density determined by Standard Penetration Resistance Consistency determined by laboratory shear strength testing, field Includes gravels, sands and silts. visual-manual procedures or standard penetration resistance

Descriptive Term Standard Penetration or Ring Sampler Descriptive Term Unconfined Compressive Standard Penetration or Ring Sampler (Density) N-Value Blows/Ft. (Consistency) Strength, Qu, psf N-Value Blows/Ft. Blows/Ft. Blows/Ft. Very Loose 0 - 3 0 - 6 Very Soft less than 500 0 - 1 < 3

Loose 4 - 9 7 - 18 Soft 500 to 1,000 2 - 4 3 - 4

Medium Dense 10 - 29 19 - 58 Medium-Stiff 1,000 to 2,000 4 - 8 5 - 9

STRENGTH TERMS Dense 30 - 50 59 - 98 Stiff 2,000 to 4,000 8 - 15 10 - 18

Very Dense > 50 >_ 99 Very Stiff 4,000 to 8,000 15 - 30 19 - 42

Hard > 8,000 > 30 > 42

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

Descriptive Term(s) Percent of Major Component Particle Size of other constituents Dry Weight of Sample Trace < 15 Boulders Over 12 in. (300 mm) With 15 - 29 Cobbles 12 in. to 3 in. (300mm to 75mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand #4 to #200 sieve (4.75mm to 0.075mm Silt or Clay Passing #200 sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Term(s) Percent of Term Plasticity Index of other constituents Dry Weight Non-plastic 0 Trace < 5 Low 1 - 10 With 5 - 12 Medium 11 - 30 Modifier > 12 High > 30

Exhibit C-1 UNIFIED SOIL CLASSIFICATION SYSTEM Soil Classification A Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests Group Group Name B Symbol E F Gravels: Clean Gravels: Cu  4 and 1  Cc  3 GW Well-graded gravel C F More than 50% of Less than 5% fines Cu  4 and/or 1  Cc  3 E GP Poorly graded gravel F,G,H coarse fraction retained Gravels with Fines: Fines classify as ML or MH GM Silty gravel Coarse Grained Soils: C F,G,H on No. 4 sieve More than 12% fines Fines classify as CL or CH GC Clayey gravel More than 50% retained E SW Well-graded sand I on No. 200 sieve Sands: Clean Sands: Cu  6 and 1  Cc  3 D I 50% or more of coarse Less than 5% fines Cu  6 and/or 1  Cc  3 E SP Poorly graded sand G,H,I fraction passes No. 4 Sands with Fines: Fines classify as ML or MH SM Silty sand D sieve More than 12% fines Fines classify as CL or CH SC Clayey sand G,H,I PI  7 and plots on or above “A” line J CL Lean clay K,L,M Inorganic: J K,L,M Silts and Clays: PI  4 or plots below “A” line ML Silt Liquid limit less than 50 Liquid limit - oven dried Organic clay K,L,M,N Organic:  0.75 OL Fine-Grained Soils: Liquid limit - not dried Organic silt K,L,M,O 50% or more passes the PI plots on or above “A” line CH Fat clay K,L,M No. 200 sieve Inorganic: K,L,M Silts and Clays: PI plots below “A” line MH Elastic Silt Liquid limit 50 or more Liquid limit - oven dried Organic clay K,L,M,P Organic:  0.75 OH Liquid limit - not dried Organic silt K,L,M,Q Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-inch (75-mm) sieve H If fines are organic, add “with organic fines” to group name. B If field sample contained cobbles or boulders, or both, add “with cobbles I If soil contains  15% gravel, add “with gravel” to group name. or boulders, or both” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly whichever is predominant. graded gravel with silt, GP-GC poorly graded gravel with clay. L If soil contains  30% plus No. 200 predominantly sand, add “sandy” to D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded group name. sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded M If soil contains  30% plus No. 200, predominantly gravel, add sand with silt, SP-SC poorly graded sand with clay “gravelly” to group name. 2 N (D ) PI  4 and plots on or above “A” line. E 30 O Cu = D60/D10 Cc = PI  4 or plots below “A” line. P D10 x D60 PI plots on or above “A” line. Q F PI plots below “A” line. If soil contains  15% sand, add “with sand” to group name.

G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

Exhibit C-2