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HomeMy WebLinkAboutCT 93-04; Village L Rancho Carillo-Horton; Village L Rancho Carillo; 1999-12-01«• 1 I II ,/X : i I T NICAI. is UPDATE REPORT VILLAGE L, RANCHO CARILLO CARLSBAD, CALIFORNIA PREPARED FOR D.R. MORTON ENCINITAS, CALIFORNIA DECEMBER 1999 GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS Project No. 05845-12-49 December 14, 1999 D. R. Horton 1010 South Coast Highway, Suite 101 Encinitas, California 92024 Attention: Mr. Stefan Lacasse Subject: VILLAGE L RANCHO CARRILLO CARLSBAD, CALIFORNIA UPDATE REPORT Reference: 1. Memorandum Rancho Carrillo, Village L, CT 99-11, prepared by the city of Carlsbad Engineering Department, dated December 8, 1999. 2. Final Report of Testing and Observation Services During Site Grading, Village L, Rancho Carrillo, Carlsbad, California, prepared by Geocon Incorporated, dated October 20, 1999 (Project No. 05845-12-33). 3. Tentative Map/Condominium Permit Master Plan Amendment Rancho Carrillo Village L, City of Carlsbad, California, prepared by Hunsaker & Associates, engineer signature dated November 23, 1999. Gentlemen: In accordance with the request of Mr. Stuart Fisk, Hoffman Planning, we herein submit our response to the plan review comment presented in the referenced memorandum [1]. This memorandum requested that a soils report be prepared that addresses the currently proposed grading/development as related to geotechnical site conditions. Our response is presented below. Review As reported in the referenced final report of grading [2], Village L is currently sheet-graded with grades on the pad varying from a high of approximately Elevation 364 feet Mean Sea Level (MSL) to a low of elevation 344 feet MSL, except for the desilting basin depression at the northwest corner. Finish grade soils are generally comprised of cut formational materials in the central and east portions of the pad and compacted fill soils within the north and west areas. 6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558^5900 • Fax (858) 558-6159 Review of the current as-graded geologic conditions with regard to the proposed building sites indicates that certain structures will be located over a cut-fill transition. This condition will require special consideration during site development as discussed below. Conclusions and Recommendations Based on the above discussion, it is our opinion that the conclusions and recommendations as presented in the referenced report of grading [2] remain applicable to the proposed grading and site development as shown on the referenced tentative map [3], with the exception as noted below, and that no geotechnical conditions exist that would prohibit the property from being developed as planned. The following recommendations are provided for consideration and implementation during finish grading of the site and installation of improvements. Grading All finish grading for site development should be performed in accordance with the attached Recommended Grading Specifications and in accordance with pertinent ordinances of the city of Carlsbad. Where the attached recommendations conflict with this section of the report, the recommendations of this section shall take precedence. All earthwork should be observed by, and all compacted fill tested by, representatives of Geocon Incorporated. Prior to commencing grading, a preconstruction conference should be held at the site with the Owner or Developer, Grading Contractor, Civil Engineer, and Geotechnical Engineer in attendance. Special soil and oversize material handling and/or the grading plans can be discussed at that time. To minimize the potential for differential settlement, it is recommended that where a cut-fill transition occurs under a building footprint, the cut portion of the building area, extending 5 feet beyond structure perimeter, should be undercut a minimum of 5 feet and replaced with fill soils compacted to at least 90 percent of related compaction (ASTM D 1557-91). The bottom of the undercut portion should be sloped 1 percent toward the fill side of the transition. Where the fill portion of the transition under the building is relatively small as compared to the cut, an acceptable alternative is to deepen the foundation in the fill portion to provide a minimum footing embedment of 12 inches into the underlying formational soils. Except where post-tensioning reinforcing is utilized, concrete slab-on-grade reinforcing in the fill portion of the building and extending 5 feet into the cut portion should consist of No. 3 bars at 24 inches on center, both directions, as a minimum. Project No. 05845-12-15 -2- December 14, 1999 The following table presents a preliminary summary of the buildings that are anticipated to be affected by cut-fill transitions and the recommended differential settlement mitigation procedure. Grading will be observed in the field by our engineering geologist and actual as-graded conditions will determine which structures will require consideration. PRELIMINARY CUT-FILL TRANSITION MITIGATION Building No. 2 7 7 8 9 11 Location Western 4 units Eastern 4 units Western 3 units (south unit) Western and Eastern 3 units (north units) Western and Eastern 3 units (north units) Northern and Southern 5 units (west units) Mitigation Procedure Undercut Cut Portion Undercut Cut Portion Undercut Cut Portion Deepen Footings Deepen Footings Deepen Footings Soil Excavation Characteristics Excavation of the fill soils should be possible with light to moderate effort with conventional heavy- duty grading equipment. Moderate to heavy effort should be anticipated for excavation in the formational soils. Excavation of the Lusardi formation and the highly cemented concretionary zones within the Delmar Formation will generally be difficult, especially for trenching operations associated with foundations and utilities, and may require heavy ripping or require special excavation equipment and will probably result in the generation of oversized material (greater than 12 inches) due to the limited fill depth the oversized material may require exporting. It should be noted that upon completion of finish grading, a report will be prepared and include final foundation design recommendations. This update report should be considered as an addendum to the previously issued final report of grading [2]. All other recommendations presented in that report remain applicable. Project No. 05845-12-15 -3-December 14, 1999 If you have any questions regarding this report update, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOC0N INCORP^RA David F. Leake RCE 22527 DFL:AS:dmc v, -,..^,Vi^rt~ Attachment: Recommended Grading Specifications (2) Addressee (4/del) Hoffman Planning Attention: Mr. Stuart Fisk CEG 1778 Project No. 05845-12-15 -4-December 14, 1999 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1. These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Geocon Incorporated. The recom- mendations contained in the text of the Geotechnical Report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 1.2. Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial conformance with the recommendations of the Geotechnical Report and these specifications. It will be necessary that the Consultant provide adequate testing and observation services so that he may determine that, in his opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep him apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3. It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture condition, inadequate compaction, adverse weather, and so forth, result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the work and recommend to the Owner that construction be stopped until the unacceptable conditions are corrected. 2. DEFINITIONS 2.1. Owner shall refer to the owner of the property or the entity on whose behalf the grading work is being performed and who has contracted with the Contractor to have grading performed. 2.2. Contractor shall refer to the Contractor performing the site grading work. 2.3. Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as-graded topography. GI rev. 8/98 2.4. Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. 2.5. Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner, who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be responsible for having qualified representatives on-site to observe and test the Contractor's work for conformance with these specifications. 2.6. Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site grading. 2.7. Geotechnical Report shall refer to a soil report (including all addenda) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended to apply. 3. MATERIALS 3.1. Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant, is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock filis, as defined below. 3.1.1. Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than 3/4 inch in size. 3.1.2. Soil-rock fills are defined as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. 3.1.3. Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than 3/4 inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. GI rev. 8/98 3.2. Material of a perishable, spongy, or otherwise unsuitable nature as determined by the Consultant shall not be used in fills. 3.3. Materials used for fill, either imported or on-site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defined by applicable laws and regulations. 3.4. The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This procedure may be utilized, provided it is acceptable to the governing agency, Owner and Consultant. 3.5. Representative samples of soil materials to be used for fill shall be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and, where appropriate, shear strength, expansion, and gradation characteristics of the soil. 3.6. During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated condition 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1. Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, brush, vegetation, man-made structures and similar debris. Grubbing shall consist of removal of stumps, roots, buried logs and other unsuitable material and shall be performed in areas to be graded. Roots and other projections exceeding 1-1/2 inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. GI rev. 8/98 4.2. Any asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility. Concrete fragments which are free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this document. 4.3. After clearing and grubbing of organic matter or other unsuitable material, loose or porous soils shall be removed to the depth recommended in the Geotechnical Report. The depth of removal and compaction shall be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.4. Where the slope ratio of the original ground is steeper than 6:1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. TYPICAL BENCHING DETAIL Finish Grade Remove All Unsuitable Material As Recommended By Soil Engineer Original Ground Finish Slope Surface Slope To Be Such That Sloughing Or Sliding Does Not Occur "B" See Note 1 See Note 2 —' No Scale DETAIL NOTES:(1) Key width "B" should be a minimum of 10 feet wide, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the bottom key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. GI rev. 8/98 4.5. After areas to receive fill have been cleared, plowed or scarified, the surface should be disced or bladed by the Contractor until it is uniform and free from large clods. The area should then be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6.0 of these specifications. 5. COMPACTION EQUIPMENT 5.1. Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a design that it will be capable of compacting the soil or soil-rock fill to the specified relative compaction at the specified moisture content. 5.2. Compaction of rock fills shall be performed in accordance with Section 6.3. 6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1. Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: 6.1.1. Soil fill shall be placed by the Contractor in layers that, when compacted, should generally not exceed 8 inches. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock materials greater than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. 6.1.2. In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTM D1557-91. 6.1.3. When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. 6.1.4. When the moisture content of the soil fill is above the range specified by the Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by the Contractor by blading/mixing, or other satisfactory methods until the moisture content is within the range specified. Gl rev. 8/98 6.1.5. After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the tn-place dry density of the compacted fill to the maximum laboratory dry density as determined in accordance with ASTM D1557-91. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum relative compaction has been achieved throughout the entire fill. 6.1.6. Soils having an Expansion Index of greater than 50 may be used in fills if placed at least 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7. Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8. As an alternative to over-building of slopes, slope faces may be back-roiled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D-8 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2. Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1. Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2. Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. GI rev. 8/98 6.2.3. For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. 6.2.4. For windrow placement, the rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 or greater and should be compacted by flooding. Windrows may also be placed utilizing an "open-face" method in lieu of the trench procedure, however, this method should first be approved by the Consultant. 6.2.5. Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center-to-center with a 5-foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. 6.2.6. All rock placement, fill placement and flooding of approved granular soil in the windrows must be continuously observed by the Consultant or his representative. 6.3. Rock fills, as defined in Section 3.1.3., shall be placed by the Contractor in accordance with the following recommendations: 6.3.1. The base of the rockf\\\ shall be placed on a sloping surface (minimum slope of 2 percent, maximum slope of 5 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-construction infiltration of water. 6.3.2. Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the GI rev. 8/98 required compaction or deflection as recommended in Paragraph 6.3.3 shall be utilized. The number of passes to be made will be determined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. 6.3.3. Plate bearing tests, in accordance with ASTM Dl 196-64, may be performed in both the compacted soil fill and in the rock fill to aid in determining the number of passes of the compaction equipment to be performed. If performed, a minimum of three plate bearing tests shall be performed in the properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be performed on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soil fill and the rock fill and by evaluating the deflection variation with number of passes. The required number of passes of the compaction equipment will be performed as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted soil fill. In no case will the required number of passes be less than two. 6.3.4. A representative of the Consultant shall be present during rock fill operations to verify that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate bearing tests will be determined by the Consultant during grading. In general, at least one test should be performed for each approximately 5,000 to 10,000 cubic yards of rock fill placed. 6.3.5. Test pits shall be excavated by the Contractor so that the Consultant can state that, in his opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In-place density testing will not be required in the rock fills. 6.3.6. To reduce the potential for "piping" of fines into the rock fill from overlying soil fill material, a 2-foot layer of graded filter material shall be placed above the uppermost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to commencing grading. The gradation of the graded filter material will be determined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the graded filter prior to the commencement of rock fill placement. GI rev. 8/98 6.3.7. All rock fill placement shall be continuously observed during placement by representatives of the Consultant. 7. OBSERVATION AND TESTING 7.1. The Consultant shall be the Owners representative to observe and perform tests during clearing, grubbing, filling and compaction operations. In general, no more than 2 feet in vertical elevation of soil or soil-rock fill shall be placed without at least one field density test being performed within that interval. In addition, a minimum of one field density test shall be performed for every 2,000 cubic yards of soil or soil-rock fill placed and compacted. 7.2. The Consultant shall perform random field density tests of the compacted soil or soil-rock fill to provide a basis for expressing an opinion as to whether the fill material is compacted as specified. Density tests shall be performed in the compacted materials below any disturbed surface. When these tests indicate that the density of any layer of fill or portion thereof is below that specified, the particular layer or areas represented by the test shall be reworked until the specified density has been achieved. 7.3. During placement of rock fill, the Consultant shall verify that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall request the excavation of observation pits and may perform plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. If performed, plate bearing tests will be performed randomly on the surface of the most-recently placed lift. Plate bearing tests will be performed to provide a basis for expressing an opinion as to whether the rock fill is adequately seated. The maximum deflection in the rock fill determined in Section 6.3.3 shall be less than the maximum deflection of the properly compacted soil fill. When any of the above criteria indicate that a layer of rock fill or any portion thereof is below that specified, the affected layer or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. 7.4. A settlement monitoring program designed by the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services performed during grading. GI rev. 8/98 7.5. The Consultant shall observe the placement of subdrains, to verify that the drainage devices have been placed and constructed in substantial conformance with project specifications. 7.6. Testing procedures shall conform to the following Standards as appropriate: 7.6.1. Soil and Soil-Rock Fills: 7.6.1.1. Field Density Test, ASTM D1556-82, Density of Soil In-Place By the Sand-Cone Method 7.6.1.2. Field Density Test, Nuclear Method, ASTM D2922-81, Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 7.6.1.3. Laboratory Compaction Test, ASTM D1557-91, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-Inch Drop. 7.6.1.4. Expansion Index Test, Uniform Building Code Standard 29-2, Expansion Index Test. 7.6.2. Rock Fills 7.6.2.1. Field Plate Bearing Test, ASTM Dl 196-64 (Reapproved 1977) Standard Method for Nonrepresentative Static Plate Load Tests of Soils and Flexible Pavement Components, For Use in Evaluation and Design of Airport and Highway Pavements. 8. PROTECTION OF WORK 8.1. During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with the Specifications prior to placing additional fill or structures. 8.2. After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. GI rev. 8/98 9. CERTIFICATIONS AND FINAL REPORTS 9.1. Upon completion of the work, Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as-built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstructions. 9.2. The Owner is responsible for furnishing a final as-graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as-graded report should be prepared and signed by a California licensed Civil Engineer experienced in geotechnical engineering and by a California Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were performed in substantial conformance with the Specifications or approved changes to the Specifications. GI rev. 8/98