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HomeMy WebLinkAboutGeoTech Soils Investigation Report - COM Engineering / Geo-Tech Reports - 7/31/2000 Geotechnical, Report SOILS I ATI INVEST N G O REPORT HARMONY HILL Union, WA Prepared By: Geotechnical Testing Laboratory Olympia, WA July, 2000 GEOTECHNICAL TESTING LABORATORY 3armony Hill 362 E. SR 106 Won,WA 98592 kttn: Mike Sumner Re: Harmony Hill Union,WA Gentlemen: with our instructions, we have conducted a soils exploration and founre odation mmendationstlon are�othe be In compliance y above mentioned project. The resultVeo co provided threehis acop. s for together with our review and distribution. found in the following report. We p exploration, soil samples were collected and submitted for laboratory testing from the project site. During our exp capacities and footing embedment depth. The The data has been carefully analyzed to determine soils bearing P e be the most results of the investigation and analysis indicate that a conventional spread footing appears foundation for the support of the proposed development. Somend totaltexpet d encountered lements suitable type of f the soil profile of the site. Net allowable soil l pressures, embedment depth, have been presented for the site later m the report. If you have any questions concerning the test results,the procedures used, or if we can be of any further assistance please call on us at (360) 754-4612. Respectfully Submitted, GEOTECHNICAL TESTING LABORATORY "W pwlprl�' Harold Parks, Engineering Geologist 10011 Blomberg Street SW,Olympia,WA 98512 Phone#: (206) 754-4612 Fax#:(206)754-4848 GEOTECHNICAL TESTING LABORATORY SUBSURFACE EXPLORATION & FOUNDATION RECOMMENDATIONS Introduction: This report presents the results of a soils exploration and foundation analysis for the proposed complex. This investigation was conducted for Harmony Hill, near Union WA. Authorization: Authorization to perform this exploration and analysis was in the form of a written authorization to proceed from Mike Sumner. Purpose: The purpose of this foundation exploration and analysis was to determine the various soil profile components, the engineering characteristics of the foundation materials and to provide criteria for use by the design engineers in preparing or verifying the suitability of the foundation design. Scope: The scope of the exploration and analysis included a review of geological maps of the area and geologic and related literature, a reconnaissance of the immediate site, surficial examination, field and laboratory testing, and an engineering analysis and evaluation of the foundation materials. General: The exploration and analysis of the foundation conditions reported herein are considered sufficient in detail and scope to form a reasonable basis for the foundation design. Any revision in the plans for the proposed structures from those enumerated in this report should be brought to the attention of the soils consultant so that he may detemiine if changes in the foundation recommendations are required. If deviations from the noted subsurface conditions are encountered during construction, they should also be brought to the attention of the soils consultant. The soils consultant warrants that the findings, recommendations, specifications, or professional advice contained herein, have been promulgated after being prepared according to generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics and engineering geology. No other warranties are implied or expressed. 10011 Blomberg Street SW,Olympia, WA 98512 Phone#: (206)7544612 Fax#: (206)7544848 G EOTECHNICAL TESTING LABORATORY This report has been prepared for the exclusive use of Harmony Hill and their retained design consultants. Findings and recommendations within this report are for specific application to the proposed project. All recommendations are according to generally accepted soils and foundation engineering practices. General Geology Of Area: The soil as described by the Coastal Zone Atlas of Washington for Mason County is a Vashon till. General Climate Of Area: The climate is temperate and marine. The influence of the Puget Sound and the Pacific Ocean modifies summer and winter temperatures and eliminates periods of extreme heat and cold. DESCRIPTION OF SITE Site Location: The site for the proposed complex, which is the subject of this report, is located to the south of SR 106 and east of Alderbrook, near Union, WA. [See vicinity map.] Site Topography, Drainage And Vegetation: The site is situated on a slight bluff gently sloping toward SR 106 to the north. The site has extensive ditching in and around the roads, parking and buildings in order to alleviate surface runoff. Most of the area around the complex is used as garden and lawn. Native vegetation, predominantly evergreen trees are found farther to the south, upslope and away from the complex. All drainage percolates about three ft. into the ground 1 through the top layer and travels over the surface of the impervious layer underneath to the roadside ditch ! along SR 106. The site is currently being used as a complex for Harmony Hill. FIELD EXPLORATION General Notes: The field exploration to determine the engineering characteristics of the foundation materials included a reconnaissance of the project site, performing field penetrometer tests and recovering disturbed grab samples. Testing Procedures: Penetrometer Tests - From the samples obtained, penetrometer tests were performed to obtain approximate bearing capacities of the individual soils strata. The results of the penetrometer tests provide a direct reading of bearing capacity of the soils being tested. 10011 Blomberg Street SW,Olympia, WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 G EOTECHNICAL TESTING LABORATORY FOUNDATION DISCUSSION AND RECOMMENDATIONS General Notes: Two requirements must be satisfied in the design of foundations. First, the load must be less than the ultimate bearing capacity of the foundation soils to maintain stability; and secondly, the differential settlement must not exceed an amount that will produce adverse behavior to the superstructure. The allowable settlement is usually exceeded before bearing capacity considerations become important; thus, the allowable bearing pressure is normally controlled by settlement considerations. Considering the subsurface conditions and the proposed construction, it is recommended that the structure be founded upon conventional reinforced concrete footings. Settlements should not exceed tolerable limits if the following design and construction recommendations are observed. Foundation Design Recommendations: On the basis of the data obtained from the site and the test results from the various laboratory tests performed, GEOTECHNICAL TESTING LAB recommends that the following guidelines be used for the net allowable soils bearing capacity. Net Allowable Footing ASTM D 1557 Soils Bearing Depth Subgrade Compaction Capacity 18" 95 % 2,000 lbs./ft2 Any excessively loose or soft spots or areas that do not meet the compaction requirements that are encountered in the footing subgrade will require over-excavation and backfilling with at least 2 ft. of structural fill. In order to minimize the effects of any slight differential movement that may occur due to variations in the character of the supporting soils and any variations in seasonal moisture contents, it is recommended that all footings be suitably reinforced to make them as rigid as possible. CONSTRUCTION CONSIDERATIONS Earthwork: It is recommended that all loose soils and deleterious materials be stripped from the foundation area to the firm native soil and wasted. Exact depths of stripping should be adjusted in the field to assure that the entire root zone is removed. It is recommended that the final exposed subgrade be inspected by a representative of the soils consultant. This inspection should verify that all organic material has been removed. Any soft spots or deflecting areas should be removed to firm native soil and/or replaced with structural fill. After the existing subgrade soils are excavated to design grade,the footing area shall be compacted to 95% of the maximum dry density as per ASTM D-1557. Enough density tests should be taken to monitor proper compaction. For structural fill beneath any of the structures, one in-place density test per lift for every 100 sq. ft. is recommended. 10011 Blomberg Street SW,Olympia, WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 GEOTECHNICAL TESTING LABORATORY Water Level Measurements: - Groundwater was observed in the roadside and various other ditches on the site. In relatively pervious soils, such as sands, indicated groundwater elevations are considered to be reliable groundwater levels. In impervious soil (cohesive), the accurate determination of the groundwater elevation may not be possible even after several days of observation. Seasonal variations, temperature and recent rainfall conditions may influence the level of the groundwater table and volumes of water will depend on the permeability of the soils. Laboratory Testing Program: Along with the field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of the foundation materials necessary in analyzing the behavior of the proposed structures. The laboratory testing program included supplementary visual classification and water content determinations on all samples. In addition, selected samples were subjected to Grain Size Analysis. SUBSURFACE CONDITIONS General Notes: The types of foundation materials encountered have been visually classified and are included in the report. The results of the field penetrometer and other laboratory tests are presented in the report. Description Of Foundation Materials: The geology of the area as taken from the "Coastal Zone Atlas, Volume 9, Mason County" consists of Vashon till (Qvt) that transitions into Pleistocene sand deposits older than Vashon till along SR 106. The Vashon till was deposited by the Vashon Stade of the Frazier Glaciation. The Pleistocene sand deposits consist of sands, silty sands, and pebbly sands commonly bedded and may contain gravel lenses and inter- bedding with the sands. On this site there was noticeable inter-bedding of gravel with the native sands. The native soils can be considered at or near their natural angle of repose, and that the factor of safety for most of the slope will be near unity. PROJECT DESCRIPTION The purpose of this section is to enumerate details of the proposed structures. The following information was provided by the project manager. The construction would consist of wood frame structures not to exceed two stories in height. Conventional reinforced spread footings and reinforced slab-on-grade are contemplated. Differential settlements are limited to 3/4 inch. Loads of 2,000 pounds per sq. ft. were assumed for settlement calculations. 10011 Blomberg Street SW,Olympia,WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 GEOTECHNICAL TESTING LABORATORY ,ccavation equipment may disturb the bearing soils and loose pockets can occur at the bearing level that were )t disclosed by the soil borings. For this reason, it is recommended that the bottoms of the excavations be ►mpacted in place by vibratory compactors. The upper 12 inches should be recompacted to achieve an in- ace density of not less than 95 percent of the maximum dry density as determined by ASTM D-1557. Tuctural Fill: uctural fill should consist of a 3" minus bank run material with no greater than 2% passing the 200 sieve. 1 structural fill below the footing should be placed outside the perimeter of the foundation for a distance of least equal to the thickness of the fill between the bottom of the foundation and the underlying soils. The mpacted backfill for the support of the foundation, the subgrade preparation and the placing of the backfill auld be monitored continuously by a testing laboratory so that the work is performed according to these :ommendations. icavations: allow excavations required for construction that do not exceed four ft. in depth may be constructed with e slopes approaching vertical. Proper care must be taken to protect personnel and equipment. nor Slab on Grade: :ore the placing of concrete floors or pavements on the site, or before any floor supporting fill is placed, the anic, loose or obviously compressive materials must be removed. The subgrade should then be proof ed to confirm that the subgrade contains no soft or deflecting areas. Areas of excessive yielding should be avated and backfilled with structural fill. Y additional fill used to increase the elevation of the floor slab should meet the requirement for structural Structural fill should be placed in layers of not more than 12 inches in thickness, at moisture contents at above optimum, and compacted to a minimum density of 95% of the maximum dry density as determined A,STM designation D-1557. ;ranular mat should be provided below the floor slabs. This should be a minimum of four inches in kness and properly compacted. The mat should consist of sand or a sand and gravel mixture with non- tic fines. The material should all pass a 3/ inch sieve and should contain less than 5% passing the #200 e. Because groundwater can be expected to be at shallower depths during the winter months, a moisture ier may be placed beneath all floor slabs. 10011 Blomberg Street SW Olympia,ympa WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 i GEOTECHNICAL TESTING LABORATORY Lateral Earth Pressures: Lateral earth pressures are dependent upon the backfill materials and their configuration and moisture content. An active coefficient of 0.25 for lateral pressures and a friction coefficient of 0.60 may be used for the structural fill. Groundwater Control: Groundwater was encountered at the time the field exploration was conducted. Groundwater is expected to cause some difficulties during construction of this project. It is recommended that runoff caused by wet weather be directed away from all open excavations. The on-site soils can be expected to become soft and pump if subjected to excessive traffic after becoming wet during periods of bad weather. This can be avoided by constructing temporary or permanent driveway sections should wet weather be forecast. The footing drain on all structures shall be placed so that the pipe invert is below the bottom of the footing and roof drains are not connected to the footing drain. On-site internal driveways should be constructed so that the roadside ditch acts as an interceptor. This can be accomplished by placing the bottom of the ditch 6 inches into the impervious soil and maintaining a positive gradient to the discharge area. Should the ditch become excessively steep or deep, the ditch can be filled with quarry spawl (6 in. minus) to maintain safety. This should only be needed on the southernmost side of the highest road. Geoseismic Setting: This project site is located within a "Zone 3 Area" as per the 2000 edition of the Uniform Building Code. All building structures on this project should be designed as per the U.B.C. requirement for such a seismic classification. The material on site has a soil profile SD with 600 ft./sec. < Vs _> 1,200 ft./sec shear wave velocity. Slope Stability: The slope is classified by the Coastal Zone Atlas for Mason County as "intermediate". Intermediate slopes consist of areas considered to have less than critical geologic, groundwater, or wave erosion factors, but which may become critical, and therefore subject to landsliding if disturbed. A common example is a stabilized and vegetated sand and gravel talus slope, the surface of which is sloping at the angle of repose or less (less than approximately 70 percent (35 degrees). Intermediate slope stability includes heavily vegetated, very steep slopes underlain by sand, gravel, till and/or bedrock. Erosion at the toe of slope is absent except when the state pulls the ditch along SR-106. Slopes may fail by a number of mechanisms, depending on the nature of the soil involved and the arrangement of natural earth materials at the site in question. Slope failures occur because forces tending to cause 10011 Blomberg Street SW,Olympia,WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 GEOTECHNICAL TESTING LABORATORY instability exceed those tending to resist it. Generally, the driving forces are represented by a component of soil weight downslope and the resisting forces are represented by the soil strength acting in the opposite direction. The factor of safety (FS) of the slope is expressed as the ratio of the resisting forces or "moments" to the driving forces or "moments". When the FS is 1 or less, the slope must fail. When the FS exceeds 1, the slope is theoretically stable. When estimating the FS for the slopes encountered, we considered 4 types of information: 1. the soil and water profiles 2. the kinematics of the potential slope failure 3. the strength and weight of the soil 4. the proposed slope geometry We have calculated "worst case" scenarios and have found that the on-site soil can support slopes with the buildings at there proposed locations. (see site plan) Please bear in mind that any slope exposed to the elements will weather and deteriorate until vegetation returns to the surface of the slope. Slopes in excess of one ft. vertical to one ft. horizontal should be supported by an engineered retaining structure. If no retaining structures are used, sloughing of the slope along the driveway approach can be expected. Impact Analysis: We do not anticipate that the proposed project will have any off-site impact. On-site care should be taken during construction to make sure that runoff caused by wet weather be fenced to protect drainage ways from siltation. Liquifaction Potential: The materials on site are of a cohesionless nature, consisting of semi-cemented materials. The potential for liquefaction of the soils in this area is negligible and not expected to present any problems for the project. Hillside Foundations (Daylight Dimension): Structures built on sloping sites offer a number of potential problems. Fig. 1 illustrates a basic consideration for what is called the "daylight" dimension, which is the horizontal distance from the bottom of the footing to the adjacent ground surface. Many building codes require a minimum distance for this dimension in order to assure some safety against the pushing out of the footing in the downslope direction. Logically, the limit for this distance depends on the type of soil and the angle of the slope of the ground surface. For low slope angles, a reasonable daylight dimension is assured simply because of the usual 10011 Blomberg Street SW,Olympia,WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 GEOTECHNICAL TESTING LABORATORY requirements for the minimum depth of the bottom of the footing below the surface in a vertical direction. As the slope increases, the daylight dimension is less assured and should be limited to some minimum distance. A depth of 32 inches will provide the critical exposure necessary. A common problem with hillside construction is that shown in Fig. 2, where recontouring of the construction site results in a portion of the building being placed on some significant depth of fill. If possible, all of the footings should be carried down to a depth below the fill. If structural fill is used and placed with reasonable compaction, it may be possible to rest the footings in the fill, provided that this is done only with inspection and supervision by a soils testing firm. General Comments: When the plans and specifications are complete, or if significant changes are made in the character or location of the proposed structure, a consultation should be arranged to review them regarding the prevailing soil conditions. Then it may be necessary to submit supplementary recommendations. It is recommended that the service of a qualified soils consulting firm be engaged to test and evaluate the soils in the footing excavations before concreting to determine that the soils meet the compaction requirements. Monitoring and testing should also be performed to verify that suitable materials are used for structural fills and that they are properly placed and compacted. 10011 Blomberg Street SW,Olympia, WA 98512 Phone#: (206)7544612 Fax#:(206)7544848 GEOTECHNICAL TESTING LABORATORY APP NDIX GENERAL NOTES SITE PLAN VICINITY MAP TOPOGRAPHIC MAP SLOPE STABILITY MAP GEOLOGIC MAP DIRECTION OF GROUNDWATER FLOW SLOPE PROFILES DAYLIGHT DIMENSION 10011 Blomberg Street SW,Olympia, WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 GEOTECHNICAL TESTING LABORATORY GEOTECHNICAL GENERAL NOTES SOIL PROPERTY SYMBOLS N: Standard"N"penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2 inch O.D.split-spoon. Qu: Unconfined compressive strength,tons/ft2 Qp: Penetrometer value,unconfined compressive strength, lbs/ft2 V: Vane value,ultimate shearing strength,lbs/ft2 M: Water content,% LL: Liquid limit,% PI: Plasticity index,% D: Natural dry density, lbs/ft3 WT: Apparent groundwater level at time noted after completion. DRILLING AND SAMPLING SYMBOLS SS: Split-Spoon- 1 3/8" I.D., 2" O.D.,except where noted. ST: Shelby Tube-3"O.D.,except where noted. AU: Auger Sample. DB: Diamond Bit. CB: Carbide Bit. WS: Washed Sample. RELATIVE DENSITY AND CONSISTENCY CLASSIFICATION Terms(Non-Cohesive Soils) Standard Penetration Resistance Very Loose 0-2 Loose 2-4 Slightly Compact 4-8 Medium Dense 8- 16 Dense 16-26 Very Dense Over 26 Terms(Cohesive Soils) Qu-(tons/ft2) Very Soft 0-0.25 Soft 0.25-0.50 Firm(Medium) 0.50- 1.00 Stiff 1.00-2.00 Very Stiff 2.00-4.00 Hard 4.00+ PARTICLE SIZE Boulders 8 in. + Coarse Sand 5 mm-0.6 mm Silts 0.074 mm-0.005 mm Cobbles 8 in.-3 in. Medium Sand 0.6 mm-0.2 min Clays 0.005 mm&Smaller Gravel 3 in.-5 mm Fine Sand 0.2 mm-0.074 mm 10011 Blomberg Street SW,Olympia,WA 98512 Phone#: (206)754-4612 Fax#: (206)754-4848 G EOTECHNICAL TESTING LABORATORY SITE PLAN � A c R I of , scat r i Muster Plan Legend for Harmony Hill or Union A. Septic Systen, B, Power Service M. Classroom/Mecung C. Main House N. Treehouse D. Office 0. Guest Cabins E. Guest House P. Director's House F. Open Air Classroom/Pavilion Q. Bath House G. Guest Dwelling R. Storage H. Guest Dwelling II S. Steps to the Water I. Kitchen/Dining T. Nature Trails J. Greenhouse U. Sire Drainage IC Resource Center V. Well House L. Maintenance Shop with Caretaker's Apartment 10011 Blomberg Street SW, Olympia, WA 98512 All � . •n"aa �+• /'r FRI.W- ,4 o" AMINO— es FA Sir fir',\ �-� "• 1',; r l AM Cal �� •`� -fit,,,/ � ��.. GEOTECHNICAL TESTING LABORATORY TOPOGRAPHIC MAP -- - ------ - --- '. 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UUUt„ UU ' ro UrUi CrUy r prpy� r fr(y/� truw r prpy� prpy� pp�� r r r pppp r Gr�pp r r r na �] J O� A J O W 01 0 N 0 O� A �O OJD N N '1 M C RE 0 Caa a c C C C CSC `fir Grid Line 1 Chart 2 Slope Profile 6 1 20.00 1 00.00 Elevation (feet) 60.00 - ---- --- - ----- - 40.00 .. -- -------------------------------- 20.00 ----- -......----- - 0.00 0 100 200 300 400 500 e00 Horizontal Distance(Feet) Page 1 GEOTECITNICAL TESTING LABORATORY daylight FIGURE-" 1 Critical exposure condition for a hillside'l'ooting. FIGURE 2 , Problems of foundations on graded hillside sites. 10011 Blomberg Street SW, Olympia, WA 98512 -Phone#: 6 9 754-4612 Fax#: 0 6 9 754-4848 Correspondence MASON COUNTY PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER Shehon,Wuhington 98584 DATE: September 23rd, 2003 INTER-DEPARTMENTAL COMMUNICATIONS TO: Scott Longanecker, DCD - Planner FROM: Alan A. Tahja, P/W- Co. Hydr. Engr. WO# PLG-03 SUBJ: Geo & SSP Plan Review NAME: Harmony Hill g Union MEP2003-00054 Scott, The Stormwater Site Plan (SSP) and geotechnical report prepared for proposed improvements to the Harmony Hill Retreat in Union has been received and reviewed by Public Works. The geotechnical report appears to comply with County reporting requirements, and recommendations in the report appear to have been incorporated into the proposed drainage work. Plan sheet 1, in the general notes (#11) indicates that"Connection may not be made to the catch basin at SR-106 without the written permission of Mason County.(Pending)"This requirement stems from the `Blackbear Resort" flooding and landslide problems several years ago which resulted in the installation of the culvert under SR-106, and the County's obligation to maintain it. I contacted Gary Yando, the County's Director of Utilities and Waste Management regarding this issue, and Gary indicated that he had two concerns which he'd expressed in 2002 in a letter written to Mr. Christopher Webb, P.E. (attached). The concern that a sump be installed is included in the current plans and appears acceptable. The second concern expressed by Gary was his position that the cost of maintaining the system should be shared between the County and the applicant. The applicant should contact Mr. Yando (County phone extension 270) to work out an agreement regarding maintenance costs. I've also contact Brad Lindgren, WSDOT's hydrologist to see if he had any issues relating to this proposal. Brad felt the details had already been worked out to his satisfaction, but indicated that a general permit would be required to be acquired b the applicant for an work within the State right g P q q Y PP Y g of way. The applicant should contact Larry Anderson 3 5 7-2 7 0 9 FAX 3 5 7-2 74 8 Email : andersl@wsdot .wa.gov regarding State access and general permit issues. Once these issues have been worked out, the proposed project appears acceptable. File: H:\WP\Strmwtr\Reviews\Harmony Hill.doc �oN.STA o A o N MASON COUNTY r o N Z UTILITIES & WASTE MANAGEMENT z� N Y 1 MASON COUNTY BLDG. II • 410 N. 41 ST. • P.O. BOX 578 1864 SHELTON, WA 98584 • (360) 427-9670 September 25, 2003 Mr. Christopher Webb, P.E. 2020 ENGINEERING, Inc. 700 Dupont Street Bellingham, Wa. 98227 Dear Mr. Webb: In February 2002 I forwarded a letter to you regarding the information you sent in relation to the Harmony Hill project. I received no response to the items I mentioned in that letter. On September 24, 2003 1 was contacted by Mr. Allan Tahja, Mason County Public Works Department. He informed me that the project was moving forward and that he want to know if I had anything that needed to be included in any approvals. He also pointed out, as I understand it, the plan now calls for a energy dissapating and sedimentation vault which would pick up down hill flow before it enters into our existing catch basin. It appears that this direction is being in order to take care of the concern we expressed in our earlier letter in which we pointed out that the we felt that it would be beneficial to redo the manhole and include a sump. Are we correct in our assumption? I am still a bit concerned about impacts to the existing catch basin and our maintenance of the line. For some time now we have not experienced any problems related to the flows or the cleaning of the culverts. Because we are the responsible party through an agreement with the state we want to make sure that it remains that way. Based on what I understand at this time it would appear that an agreement would be of benefit where the developers of Harmony Hill would share in the maintenance of the system from the existing catch basin to under the highway to the beach. I re ec fully request your input in this matter and look forward to hearing from you. Sin ely, ary Y Cc: Allan Tahja Scott Longanecker GARY YANDO,DIRECTOR r Please feel free to contact me at County extension 461 if you have any questions regarding these comments, or if you feel any features need further discussion or attention. SirIcArely, � L Al n A. Tahja Attached; Yando Letter dated February 12, 2002 File: H:\WP\Strmwtr\Reviews\Harmony Hill.doc �pN.STq P C MASON COUNTY o N y= UTILITIES & WASTE MANAGEMENT z� N Y ti MASON COUNTY BLDG. II • 410 N. 4' ST. • P.O. BOX 578 0 � SHELTON, WA 98584 • (360) 427-9670 1864 February 12, 2002 Mr. Christopher Webb PE. 2020 ENGINEERING, INC. 700 Dupont Street PO Box 1621 Bellingham, WA. 98227 Dear Mr. Webb: Wanted to take this opportunity to inform you that I had received you overall site plan(Phase 1 drainage and road improvements) dated January 25, 2002 -Harmony Hill of Union. I have done some review of the information I have. I did notice that their appears to be a bit of a discrepancy in the length of pipe running along Hwy. 106. From where your 18"CPEP runs into the manhole it is my understanding the line going east to where it goes under Hwy. 106 is a 36" line. It looks like on the drawing it is noted as 12". I am also concerned with the manhole you plan to direct the flow. As part of our cleanup program we had the system televised and in discussions with our contractor it appears that it would be beneficial to redo the manhole and include a sump. Have you checked it out to determine if any additional state or local permits are needed? State Hwy. Department because the line we maintain is on their right-of-way. What about additional discharge out of the 36" line into the canal? It would also be appropriate to look at sharing the cost of maintaining the system. I ask that you review the above and forward any comments you may have back to me. I would suggest that we meet regarding this so I can make sure that I have a clear understanding. If you have any questions, please call me at X270. Sin a ely, Gary Y o GARY YANDO,DIRECTOR