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HomeMy WebLinkAboutOn-Site Grey Water Disposal - PLN General Project Report for Camp Lyle McLeod On-Site Grey Water Disposal System Description Camp Lyle McLeod is a Girl Scout Camp, located in Mason County, Washington, operating primarily during several weeks during the summer and on weekends throughout the year. The water system is served by two wells with a combined capacity of approximately 23 gpm. A 30,000-gallon reservoir provides equalization and stand by storage as well as elevation head as a gravity-pressurized system. The distribution system consists of a large loop composed of 6-inch and 4-inch pipe with several 2-inch and'/4-inch branch lines. The system is managed by the camp manager: Arthur"Art" Wightman 800 NE Twin Lakes Rd Tahuya, WA 98588 The camp is rather primitive in nature. Water uses include: central shower facilities, a main lodge with a kitchen and bathrooms, cabin clusters with 1-2 hose bibs each, a caretaker's residence, and a couple of cabins with bathrooms and kitchenettes. Waste water disposal is accomplished through several separate on-site disposal units. In addition,the outhouses are pumped annually and the waste is trucked off-site for disposal elsewhere. Problem Description The camp desires to expand by adding a new"yurt village". Currently the site is available for tent camping. The yurt village will consist of five yurt cabins with a capacity to house 30 campers and staff. Additional structures include an outhouse and cook shelter. At present only the outhouse is existing. The outhouse is served by a 1,000-gallon cement tank,which is pumped annually. No changes to the outhouse are proposed. An existing hose bib is located outside the outhouse facility for hand washing. Currently,the water from this hose bib runs off on the surface over and along the road servicing the campsite. An additional hose bib is proposed at the comer of the proposed cook shelter. This water will be used for cooking and washing dishes. The current dishwashing practices for the camp stipulate the three basin technique. Currently, the dirty water from these basins is disposed of by land surface application in the adjoining woods. The Mason County Health Department is requiring alternative disposal methods for the current and proposed water uses that include subterranean on-site disposal. Sizing The capacity of the yurt village shall be 30 persons. Several similar"cabin"villages are currently in use throughout the camp. Therefore,these shall be used as "comparative systems"to estimate water usage and the necessary disposal capacity. Based upon these other systems,water usage will be approximately 30 gpd. This amount shall be multiplied by a safety factor of 1.75 for the purposes of sizing the system, for a total of 52.5 gpd. While these amounts may appear to be low, the camping facilities and programs are fairly primitive. hi addition,part of the Girl Scout's camping program includes conservation and wise use of natural resources. The primary soils in the infiltration zone according to an analysis completed by GeoEngineers are sandy till with an infiltration rate of approximately 1.0 gpd/ft from two to six feet. The test hole was completed to a depth of 8 feet with the region from six to eight and one-half(plus)feet consisting of clean cemented sand. The cemented sand may or may not be a restricting layer; however,the minimum open interval of 36-inches is satisfied even if this layer is restrictive. The drainfield must have a minimum available area of 52.5 ft2. A single infiltrator has a capacity of 77 gallons and an area of 18.75 ft . Therefore,three infiltrators are specified for a total of 56.25 ft2 and 231 gallons. If for some reason water usage between the two hose bibs exceeds 52.5 gallons,the three infiltrators have an additional capacity of 178.5 gallons of"equalization storage". Solution Each hose bib shall be equipped with a drain box to catch the water used by the campers. The drain shall be no less than 4-inches in diameter. The drain shall be screened with a non-corrosive screen with a maximum opening size of 1/8-inch. The screen is for the purpose of preventing food scraps, leaves, and rodents from entering the disposal system. Transport lines shall carry wastewater to an infiltration chamber. Slope of the transmission lines shall be a minimum of 1/4"per foot. Where the transmission line crosses the service road, it shall be sleeved in 6-inch steel pipe, or other approved material to protect it from vehicular traffic. The infiltrators shall be located in a trench three feet wide, 19 feet long and three feet deep. The trenches are one foot high for a total of two feet of cover. This allows the infiltration to occur in the zone listed as having"rapid seepage" qualities. The rapid seepage description indicates that infiltration rates are most likely much higher than the theoretical rating of 1.0 gpd/ft2; nevertheless,the minimum possible infiltration rate shall be assumed. The proposed location of the infiltrators is 20-40 feet from the test hole. Several other test holes in the general area have yielded very similar results, indicating that the soil profile is quite uniform and that the soils in the proposed drainfield area will have equally acceptable properties. Site inspection of the open trench shall confirm the soil type(s). Conclusion The proposed design is conservative in nature and employs sound engineering practices. The specifications herein attempt to meet or exceed all WSDOH requirements. Preparation Q P O WA O,p� of h Northwest Water Systems, Inc. yT % P.O. Box 123 s Port Orchard, WA 98366 (360) 876-0958 �S10MA4 Report Prepared By: Under the Direction of: rEXPIRES 7 ZZ O( ��� Todd Krause, E.LT. Danford A. oore, P.E. . SUN-27-04 SUN 02 :57 PM 2736378M7378423236837 4791508 _ .__ P• 03 REPORT GEOTECHNICAI_ ENGINECRING SERVICE$ CAMP LYLE McLEOD DEVELOPMENT PROJECT BELFAIR, WASHINGTON FOR GIRL SCOUTS OF AMERICA—TOTEM COUNCIL INTRODUCTION This report was prepared for the Girl Scouts of America — Totem Council and presents the results of our geotechnical engineering services for the proposed Camp Lyle McLeod Development Project near Belfair, Washington. Camp Lyle McLeod is located approximately 6 miles northwest of Belfair as shown on the Vicinity Map, Figure 1 and on the Site Plans, Figures 2 and 3. Our understanding of the project is based on information provided by Paul Kosteniuk and a meeting at the camp on December 19, 2002. In attendance at the meetings were Jim Messmer and Art Whightman of the Totem Council, Paul Kosteniuk, Don Mackay of GGLO, the project architect, Mike Wright of Swenson Say Faget, the project structural engineers and others. We also reviewed the geologic and topographic maps for the site and vicinity. We understand that the camp improvements will consist of the following: • A new camp site to be titled the Yurt Village that will include several individual camping ' shelters and a cook/dining house. • A new Camp Manager's residence. SCOPE OF SERVICES The purpose of our services is to assist the project team with the geotechnical aspects of the proposed camp improvements. Our scope includes the following tasks: 1. Review existing geologic and subsurface information for the site and surrounding area contained in our files. 2. Perform a general reconnaissance of the site. 3. Explore subsurface soil and groundwater conditions by excavating 6 test pits using a backhoe. Two test pits were excavated at the new Camp Manager's residence site and four test pits were excavated at the Yurt Village site. The test pits were excavated to depths ranging from 3% to 8%2 feet below the ground surface. 4. Evaluate pertinent physical and engineering characteristics of the soils based on the results of the field exploration and our experience. 5. Provide recommendations for Site preparation and earthwork including clearing criteria, suitability of on-site soils for use as structural fill including any constraints for wet weather construction, gradation criteria for any structural fill material which may have to be imported, and fill placement and compaction requirements. 6. Perform evaluations and engineering analyses, and provide conclusions and geotechnical recommendations for the following: • Shallow foundation support, including appropriate design bearing pressures, lateral restraint and estimates of expected foundation settlement. G o o E n g i n e c r s J Filc No 10333-002-W022SO JUN-27-04 suN 03 :00 PM 273637SM7378423236637 4791508 F . 01 • Geotechnical considerations for temporary excavation support for underground utilities. • Recommendations for temporary and permanent slope inclination and protection. • Geotechnical considerations for slab-on-grade construction. • Recommendations for subgrade preparation and gravel surfacing of roads and parking areas. • Geotechnical considerations related to groundwater conditions. • Recommendations for sedimentation and erosion control during and following construction,and permanent site drainage. 7. Discuss seismicity at the site and evaluate the ealtbiluake engineering aspects of the project, including ground liquefaction. Provide seismic design parameters including peak ground acceleration and UBC site coefficient. 8. Comment on any anticipated construction difficulties identified from the results of our site studies and from our experience on projects at similar sites. 9. Prepare a written report containing our conclusions and recommendations along with our supporting field and laboratory data. SITE CONDITIONS SURFACE CONDITIONS Camp Lyle McLeod is located on an upland terrace surrounding Lake Bermeusen. Topography in the camp vicinity is hilly with generally gentle slopes. Within the camp the ground ranges from local highs of about Elevation 420 feet down to the lake level at about Elevation 380 feet. The new Camp Manager's residence area (Figure 2) is currently forested with a heavy understory growth. The ground is slightly hummocky in this area with seasonal wet areas it low ground depressions. No creeks, springs or watercourses were observed in this area. The new residence will be sited on a local high ground area at about Elevation 420 feet, Access to the residence will be from the existing gravel drive that is north of the residence The Yurt Village area (Figure 3) surrounds a currently cleared picnic area. The individual camping shelters will be sited around the clearing in areas that are currently forested with a heavy understory growth. The cook/dining house will be sited at the cleared area. The ground slopes Igently away from the cleared area that is at about Elevation 396 feet. No creeks, springs or watercourses were observed in this area. Access to the Yuri Village area is by means of a gravel drive from the northeast. SUBSURFACE CONDITIONS i Geologic Conditions .Our review of the available geologic information for the Camp Lyle McLeod area and our direct observations at the site indicate that the site is underlain by glacial till. The glacial till fconsists of a dense mixture of silt, sand and gravel that often contains cobbles and boulders. Till is typically relatively impermeable and the erosion hazard of soils derived from till is moderate where the ground is only moderately sloped,as at this site. 2 File No.1 013 3-002-00`a22503 JUN-27-04 SUN 03 :00 PM 2736370M7776423236637 4791508 P. 02 Soil and Groundwater Conditions r Shallow subsurface conditions at the site were evaluated by excavating 6 test pits at the site r1 on January 29, 2003. Details of our field exploration program and the exploration logs are presented in Appendix A. Based on the explorations, subsurface conditions are consistent with the geologic information for the area. Subsurface conditions at the specific locations that we explored are as follows: Camp Manager's Residence. The two test pits (TT-1 and TP-2) completed in the area proposed for the Camp Manager's residence encountered from '/i to I foot of forest duff and loose, silty medium to coarse sand and gravel with abundant roots and organic matter. The surface layer was underlain by medium dense, fine to coarse sand and gravel with varying silt content. This medium dense soil extends to depths of 3 to 3 '/a feet and is likely weathered glacial till. The test pits were completed at depths of 8 and 8'/z feet in very dense glacial till that consists of silty fine to coarse sand and gravel. Moderate water seepage was observed at a depth of Wa feet in TP-l. No water seepage was observed in TP-2. Yuri Village. The four test pits (TP-3 through TP-6)completed in the area of the proposed Yurt Village each encountered about '/a foot of forest duff and loose,silty medium to coarse sand and gravel with abundant roots and organic matter. The surface layer was underlain by medium dense, fine to coarse sand and gravel,or gravel with sand,with varying silt content. This medium dense soil extends to depths of 2 to 3 feet in TP-3,TP-4 and TP-6 and is likely weathered glacial t till. These test pits were completed at depths of 6'/2 to 8 feet in very dense glacial till that consists of silty fine to coarse sand and gravel. — -The soils below 2 feet in TP-5 consisted of dense sand with occasional gravel to a depth of 6 feet and clean cemented sand to a depth of 8Y2 feet. This soil is sandy till in our opinion. Rapid water seepage was observed below 3 feet in TP-5. Moderate water seepage was observed below 23/.feet in TP-6. No water seepage was observed in TP-3 or TP-4.. CONCLUSIONS AND RECOMMENDATIONS I GENERAL Based on our data review, explorations, and engineering analyses, it is our opinion that the proposed camp improvements are geotectmically feasible. The primary geotechnical considerations for these improvements are as follows: I. The proposed structures may be supported on conventional spread footings bearing on the medium dense native soils or on adequately compacted structural fill. 2. Conventional slabs-on-grade may be supported on a gravel layer over the medium dense native soils or on adequately compacted structural fill. 3. New footings should not be supported on the forest duff or surficral loose organic soil layers. Where new structures are located, the duff or loose organic soil should be removed and replaced with structural fill below the structures. G e o E n g i n e c r e 3 Filc No 10333.002-00'W25W JUN-27-04 SUN 03 _01 PM 2736378M73 8423236P37 4791508 P• 03 r z w 0. � W a a of, +r<. s+ .m A 1P q°�,'1 rP/4 a iNY"l' " 1 i �� ( {' +� b d 1 py• it J- �°/ �� 7, co CL m / h /I /' I\ rY/� CL IL fL I All Product Subject to Stock on Hand. Contact sales Department for availability and special orders. ftm i Infiltrator � M l 1 Standard and High Capacity Infiltrator chambers preside up to LTAR(Long-Term Acceptance Rate). tacks the Igflttrate capacity Of stone and pipe systems. The Infiltrator Chamber System replaces old-fashioned stone and pipe leachfields with patented, high-strength polymer chambers.Two chamber sizes are available, Standard and High Stone �wd 'Pipe Capacity, both designed to fit in a standard 36"wide trench. Infiltrator chambers sit directly on the trench bottom. The patent- 0 0.5 1.0 1.5 2.0 ed interlocks add strength and latch the chambers together This graph demonstrates the dramatic efficiency improvement in quickly, end to end, so installation takes less than half the time LIAR of Infiltrator chambers over stone and pipe trenches.The LTAR of a laborious stone and pipe job. is a measure of the long-term ability of the system to pass effluent Infiltrator chambers may be used for any application that is suit- into the soil. For example, High Capacity Infiltrator chambers move able for stone and pipe. However, by offering greater infiltrative up to twice the effluent of a same size stone and pipe trench. This capacity per linear foot, chamber systems can require as little as efficiency is recognized by many state and local jurisdictions,,who in half the space as conventional systems.* turn may allow up to 50%shorter trenches. Patented MicroLeaching7 sidewall. The Infiltrator chamber has an engineered, louvered sidewall High-density polyethylene construction. that allows effluent to pass laterally into the soil.The angled lou- Infiltrator chambers are molded of high-density PolyTuff-poly- vers prevent backfill intrusion into the chamber while 1/4"slots ethylene. This proprietary blend, including recycled resins, is for- allow lateral leaching. mulated for optimum strength and chemical resistance. It's Open chamber bottom boosts infiltration. impervious to wastewater constituents and is stabilized to resist The chamber bottom is completely open, promoting effluent ultraviolet rays. Infiltrator chambers are manufactured using an filtration into the soil with 100%efficiency.The open-bottom exclusive patented process to assure consistent high quality. a, in combination with the MicroLeaching sidewall, provides aximum infiltrative capacity for long-term, trouble-free service. AASHTO H-10 and H-20 load ratings. THERE IS A Infiltrator chambers have been structurally tested by a registered DESIGNED r0 SOLVE veo�s lua�roa' professional engineer. Both Standard and High Capacity cham- bers are available with AASHTO ratings of H-10 (16,999 lb/axle with 12" of compacted cover) or H-20 (32,000 lb/axle with 18" b "t of compacted cover). a Nomin ecificationsX43 �a a andard Chamber Size,WXLxH 3' x 6-1/4'x 1' 3'x 6Weight 27 lb.Capacity 77 gal. (1.3 cu. ft 122 g ) Item # Description Chamber Leaching Field System GRAVEL AND PIPE saaal Lack ot cover 03'512 1 72 L s).,# � nwtedal on sidewoli 026508 12'X75 STD H10 INFILTR CHIOR "Neldoted 1pe.pave Int;r- �, moy olbw Amw sou 0`2:.&.5(7i H.10 " iNl<'7;I!:It•3• ` (9R ' ,?-. ltt Studer nulon thaltttloes not We - ' awn dstnbumn sronea Qrwel 026510 H10 INFILTRATOR PLATE CLOSED W4lratna - storP0go0 sWoce.#h pompe aMy.Grwa blornd IOnblbn pioNdel no Ireotment. ones .0fo 601 a tNe wdace _ LIMITS INFILTRATIVE CAPACITY compecibn¢om wiuceond tia9bin rate Native Solt To Order, See Page 300 S221 : � \ m Fn ©\ » �e m om r:q ))/ . ! )\ §§_( m22= z gm \\ y a § )} . 2 w: O § % o y� � � p , . ©ems! y mm ^� � !|® . ])0 !§_ z § | #` >) � }\ )] // � 0 M� _ (! ; Fim 7 F 2 § )( z g y % R f > } | , 2 \ \ ) � / � c §/ a R � \ - \ ! ; ) /\ ) \ 0 m § ( ~>0 / 7 | @ \ � § ) !!§2 ; |§ \ % \ (� §/ ` - ; ¥ o z � E � . ,