GEOTECHNICAL & ENVIRONMENTAL ENGINEERING CONSULTANTS
May 22, 2023
Proposal No. 23151R2
AES Project No. 22-489-22
City of Santa Clarita
Environmental Services
23920 Valencia Blvd. Suite 295
Santa Clarita, CA 91355-2196
661-286-4058, [email protected]
Attention: Ms. Kelly Kacmar
Subject: Revised Proposal #2 – Proposed Geotechnical Diagnostic Investigation For Re-Evaluation of Site Slope Stability, Hydraulic Conductivity of Soils, And For Consideration of New Groundwater Dewatering Wells APN Nos. 2802-037-028, 2802-037-029
Lot 1 and Portion of Lot 2, Tract 36496
28085 Whites Canyon Road
Santa Clarita, CA 91351
Ladies/Gentlemen:
INTRODUCTION
As requested, and following our telephone con versation and email correspondence, we are pleased to submit this revised proposal to perform the subject investigation, described further below.
PROJECT CONSIDERATIONS
This office issued a repo rt of Geologic Assessment o f 16 Existing Hydraugers at the Monterra Ridge Apartments, also known as the Drainage Benefit Assessment Area 3, on 1/31/2023.
In our report we established that the 16 hydraugers are in various states of disrepair with only 3 actively draining the landmass . We also established that all of the hydraugers are currently well above the local groundwater level, and as such are not actively dewatering the landmass as originally designed/intended. In our report we recommended that the site slope stability be re -evaluated, since the original ev aluation and geologic site characterization of the site as underlain by an ancient landslide was determined to be very conservative at best, to possibly erroneous . After completion of the field exploration, we intend to re -evaluate the gross and seismic slope stability factors of safety of the slopes surrounding the building pad, with specific regard to the existing groundwater levels.
In our report we recommended a diagnostic geotechnical investigation to re -evaluate the site geologic model, run the slope stability analyses again using additional field exploration and laboratory and field testing of soil and bedrock samples, and provide additional recommendations as needed to drain the landmass below the apartment building s, which was the original intention of the 16 hydraugers recommended, designed and installed in 1984 as part of original site development.
For a detailed discussion of our prior findings and recommendations please see pages 68 -72 of our 1/31/2023 report.
4742 SAN FERNANDO ROAD ♦ GLENDALE, CA 91204 ♦ TEL. (818) 552-6000 ♦ FAX (818) 552-6007 ♦ www.aessoil.com SOILS & FOUNDATION INVESTIGATION ♦ MATERIALS TESTING ♦ SITE ASSESSMENT ♦ CONSTRUCTION OBSERVATION Applied
Earth
Sciences
APPLIED EARTH SCIENCES
Proposal No. 23151R
2 SCOPE OF WORK- GEOTECHNICAL
At this time, we recommend a comprehensive geotechnical field and laboratory exploration program of the existing site, re -evaluation of the slope stability model, a perfunctory prior permit and correspondence documentation /records for observation records of damage (if any) from Northridge earthquake on the existing buildings or slopes , and recommendations for installation of new groundwater pumping wells and/or new hydraug ers to replace the broken hydraugers as reported in our original report. In the case t hat the revised site slope stability model s indicate that adequate factors of sa fety already exist at the site without lowerin g the existing groundwater levels , we will report accordingly and there may not be any need for additional mitigation measures.
We recommend advancing a total of 6 new geotechnical borings to depths ranging from ~40’ to ~80’, 3 of which will be drilled by hol low-stem auger to facilitate groundwater pumping tests using 2” PVC pipe and pump, and 3 of which will be drilled by large-diameter 24” bucket auger drill rig to groundwater level to facilitate downhole logging of the boreholes and close in-situ examination of the subsurface materials. This latter drilling technique will allow us to de termine the accuracy of the original site characterization with particular respect to the landslide debris that was previ ously characterized to under lie the site . All of the bo reholes will be advanced to the current groundwater level and possibly lower.
We also plan to ad vance 4 hand-dug test holes to depths ranging from 6 ’ to 10’ along the descending slopes below the building pad, to facilitate gross and surficial slope stability analysis.
In addition, several lab oratory tests will be performed on the collected soil , slide debris and bedrock samples, for geologic site characterization, per meability and hydraulic condu ctivity of the groundwater-bearing layers, and suitability of site for dewatering wells.
Each of the tes t holes will be sampled at regular intervals of depth and at chan ges in the subsurface materials. The samples will then be tested in the laboratory to de termine the engineering properties of the subsurface soils. Laboratory testing may include, but not nec essarily be limited to the following:
1) Moisture and Density
2) Direct Shear
3) Consolidation
4) Expansion
5) Permeability and Hydraulic Conductivity
The soil data obtained from the field and laboratory testing program will be evaluated.
Engineering evaluation and a nalysis will be performed. Consultation with the involved design professionals will be provided during all phases of investigation and prior to the written report preparation. Our final reports will include the following items:
1. A site plan showing surface geology and the location of test holes;
2. Preparation of cross-sections showing subsurface condition;
3. A discussion of the materials encountered in the test holes and their engineering properties;
4. Graphical log of the e xploratory test pits summarizing the subsurface conditions encountered and the results of laboratory testing;
APPLIED EARTH SCIENCES
Proposal No. 23151R
3 5. Presentation of the results of laboratory testing in a form of plots;
6. Providing a detailed description of laboratory testing procedure;
7. Evaluation of slope stability;
8. Recommendations for temporary excavations/shoring;
9. Discussion of liquefaction potential at the site;
10. Determination of seismic risk (near source) factors;
11. Recommendations for design construction of foundations and any settlement effects due to structural loads;
12. Recommendations for lateral design;
13. Recommendations for site grading;
14. Recommendations for site surface drainage;
15. Recommendations for earth retaining structures; and
16. Recommendations for concrete grade slabs.
PROJECT COSTS AND PAYMENT SCHEDULE
We estimate that the wor k as described above will cost NOT TO EXCEED $55,000 to complete, including drilling and test hole excavation cost, groundwater pumping well installation cost, mobilization/demobilization, laboratory testing fees, engineering and geologic analysis, draftin g of geologic map and cross sections, and completion of geotechnical diagnostic investigation report. This estimate is based on Prevailing Wage rates for public works projects.
Note: the budget above is an estimate only. Actual costs may vary based on unfo reseen f ield conditions. The final total will be based on actual costs.
This proposal and s cope of work does not include con sultation during the actual repair work .
Future consultation and coordination work with the chosen contrac tor will be scoped at a l ater phase based on time and materials.
This scope of work proposal includes meetings and/or conference cal ls with city or coun ty reviewers during the duration of our evaluation work and preparation of report and scope of work.
If needed, additional consultation services will be billed on a time and materials basis.
We request that th e payment schedules be based on the following: $10,000 deposit to cover initial planning and preparation, $10,000 paya ble prior to field mobilization, $10,000 payable at compl etion of field exploration work, and the remainder due when the report is completed.
APPLIED EARTH SCIENCES
Proposal No. 23151R
4 PROJECT SCHEDULE
The scope of w ork presented abo ve can be scheduled s hortly after receiving written authorization from the client to proceed. We anticipate a preparation period of approximately 10-20 days, followed by one to two weeks of drilling, field exploration, and groundwater well pumping work. The report will follow within 6-8 weeks after completion of field exploration and laboratory testing work. A draft of our report will be shared with the city for review and comment prior to finalization.
TERMS OF AGREEMENT
This proposal acts as a contract between Applied Soil Technology, dba C.M. Applied Earth Sciences (heretofore referred as AES) and the undersigned Client. By signing be low, the Client agre es to the following terms and conditions:
1. AES does its utmost to present the results of investigations in a pr ompt manner based on the timeline estimated in this proposal/contract. However, due to the nature and sc ope of the work involved, the timeline is not guaranteed and only serves as a guideline.
2. The retainer/deposit payment is due at project initiation. Larger pr ojects will require progress payments. All outstanding balances due must be paid before final re sults and recommendations are released to Client. Reports and/or design are not issued on credit.
3. Plan review, stamp and signature; su pplements and addendum s; inspect ions; and field observation services are not included in this contract an d will be perf ormed under a separat e contract according to our current fee schedule.
4. AES makes no guarantees regarding the approval of t he report by r egulatory agencies. An y additional correspondence, information, and/or further comments requested by said agencies may result in additional fees, based on time and materials.
5. Changes or alteration s to o ur recommendations as a result of chan ge-orders and changes to plans are subject to additional fees, based on time and materials.
6. AES’ total liability to C lient for any and all injuries, cla ims, losses, expense s o r damages whatsoever arising out of or in any way related to this Agreement fro m any cause or causes, including but not limit ed to AES’ negligence, er rors, omissions, strict liability, or breach of contract shall not exceed the total amount of this Contract.
7. AES and Client agree that the discovery of unanticipated hazardous materia ls constitutes a change in the condi tion of th e j ob site mandating a re negotiation of the scope of work or termination of the project . If unanticipated h azardous materials a re encountered at the Site, AES may be required by law to report the Site’s condit ions to an app ropriate Governmental Agency and shall be held harmless in its legal obligations.
8. It shoul d be noted that propertie s are sometimes under lain by complex geol ogic conditions (ancient landslides, deep fill, fault lines, etc.). Any additional investigation beyond the scope of work as out lined in this proposal/contract and/or meetings attendant with the Governmental
APPLIED EARTH SCIENCES
Proposal No. 23151R
5 Agencies will be performed o n the basis of time and materials and in accord ance w ith our current fee schedule. Before a dditional work is perf ormed, we will consult you to recei ve supplemental authorization.
9. In the performance of the scope of work indicated above, AES will take reasonable precautions to avoid damaging buried structures and utilities, by calling DIG Alert to mark utilities in area of field work prior to field w ork, as required by law . Client assumes all li ability for cl aims arising out of bu ried structures and utilit ies that were not ca lled to AES’ attention, which were no t properly located on plans furnished to AES or which were not properly located by locating companies called to the site by or on behalf of Client to i dentify such structures and utilities.
AES is no t responsible for m arkings made by utility companies, or damage c aused by markings by utility companies.
10. Client agrees to provide for AES’ right to enter from time to ti me property owned by Client and/or others in order for AES to ful fill the scope of wor k indicated above. This right to enter shall also apply to utility companies who are called out to site by or on behalf of client to mark utilities in area of work.
11. Client agrees that all origina l documents an d drawings produced by AES in accor dance with this agreem ent, except documents which are required to be f iled with public agencies, shall remain the property of AES.
12. This proposal is valid for up to one month from date of proposal.
13. After commencement of the project (receipt of signed agreement and payment of initial deposit), the project file will be active for a 3-month period. Soil and rock samples collected during field investigations will be retained until the end of the 3 -month period . If applicable plans for the proposed i mprovements are not provided by the Client within that 3-month span, or if the projec t i s delayed or put on hold by the client for any reason beyond the 3 -month period, additional charges will apply to reactiv ate the file and/or retrieve additional soil an d bedrock samples as needed.
14. Unpermitted excavations and/or unpermitted construction th at are not brought to AES’s attention during initial scoping of the project, or that are noted during subsequent site visits that were not indicated earlier , represent changes to the scope of work that will result in additional charges to provide recommendations for remediation.
15. The parties hereto agree that this Agreement supersedes all existing agreements between the Client and Consultant AES, whether oral, written, expressed or implied, and contains the entire understanding and agreement between the pa rties. This Agreement shall n ot be amended, modified, or superseded in any respect except by a subsequent written agreement entered into by both parties hereto.
16. The Client and Consultant AES agree that any dispute or controversy arising out of, relating t o or in connection with the int erpretation, validity, construction, performance, breach or termination of this Agreement shall be settled by binding arbitration to be h eld in accordance with the Commercial Arb itration Rules of the American Arbitration Asso ciation. The Client and Consultant shall and separately pay one -half of the costs and expenses of such arbitration, including counsel’s fees and expenses, unless otherwise required by law.
APPLIED EARTH SCIENCES
Proposal No. 23151R
6 -o0o-
Thank you for the opportunity to be of service on this project. If you have any questions regarding this proposal, please call the undersig ned. If it is acceptable as written, please sign where indicated and return a copy of t his proposal to us along with the re tainer as our official approval to proceed with the investigation.
Respectfully submitted,
Applied Earth Sciences
_______________________________ May 22, 2023
Shant Minas Date
Principle Geologist, Managing Partner
PG, EG
Approved By:
_______________________________ _________________
Name & Title Date
SM/la
Distribution: (2)