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Home My WebLink AboutSoil Report - GEO Geological Review - 2/8/1983 Grover C.Way, P.E. `° R E C E I V,` � SOUTH llth STREET CONSULTING SOILS ENGINEER TACOMA. WASHINGTON 9"o2 FED Code (206) 272-gM ( 9 19t�:� BUILDING FUND February 8, 1983 W.O. 8304 North Mason School District No. 403 P.O. Box 167 Belfair, Washington 98528 Attention: Mr. Chuck Jeu Building Program Coordinator Subject: r Proposed Recreational Building Gentlemen. In accordance with your recent request, I have made a soils re- connaissance for the subject project. This was done to determine general soils conditions in the building area, particularly with re- spect to suitability for building foundations. A brief description of the investigation, together with indicated conclusions, is pre- sented in this report-. The proposed project is located at the east side of a parcel of `f about 80 acres, generally west of Belfair Elementary School . It consists of a recreation building having less than 5000 SF, probably single-story. The exact location of the building on the site has not yet been determined. Soils conditions in the general development area were explored by making a total of seven backhoe-excavated test pits; five at the higher eastern portion of the site, and two in the lower existing baseball field. All of the test pits were inspected by a representa- tive of the Mason County Health Department prior to backfilling. The test pits were made on February 7, 1983, by Ron's Earthworks of Tacoma. Test pit locations are shown on the attached Site Plan; logs of the test pits are also attached, together with a description of the soils classification system used in visually classifying the soils encountered. Moisture and density conditions described on the logs are qualitative only, with moisture conditions expressed on a dry-moist-wet basis. Soils encountered in the upper area were predominantly fine to medium sands with varying percentages of gravel , rally in a medium dense condition. There is a prominant mound of fillematerial surrounded by the test pits, which reportedly came from drainage ditch clearing. There is also some older undesirable fill toward the north end which appears to have been placed in a former low area. In this area ground- water was encountered in only one test pit (No. 4) at a depth of six feet. i i_ February 8, 1983 W.O. 8304 Page '2 ( In the playfield area, well-graded sand and gravel was encountered, with groundwater at a depth of 2-1/2 to 3 feet. Water would be expected to be closer to the ground surface during prolonged wet weather. Development of the upper portion of the site will require removal of the fill material under all paved and building areas. This removal should include the older fill material used to level out the site. Back- fill should be well-compacted bank-run sand and gravel . The proposed building may be supported on conventional spread footing foundations bearing either on the new compacted fill or on native undisturbed soil , depending on the final building location with respect to the fill areas. The lower playfield area is considered too wet for consideration as a potential building site or as a septic tank drainfield area. I appreciate the opportunity to be of continuing service to the District. Please call if there are any questions regarding my report. vsR C. it * • - '* Respe tfully submitte , . 4 • 4, �ss�ONAt� E Grover C. Way, P.E. Soils Engineer GCW/sso cc: Mason County General Services l Grover C.Way, P.E. r r I APPENDIX i Grover C. Way, P.E. l T E S T P I T L 0 G S TEST FIT i DEPTH - FEET 0.0 - 0.5 Brown, organic topsoil (loose, moist) 0.5 - 6.5 Brown, silty SAND with minor gravel (loose becoming medium dense, moist) 6.5 - 12.0 Brown, gravelly. SAND (medium dense, wet) Light to moderate seepage of 8.0 feet Some caving below 7.0 feet TEST PIT 2 i DEPTH - FEET 0.0 - 1.5 Dark brown organic (peaty) topsoil (soft, wet) 1.5 - 4.0 Grey clayey silt interbedded with coarse Sand and Gravel (soft loose, wet) 4.0 - 12.0 Grey varied clayey silt (soft to medium stiff, wet) Light to moderate seepage below 1.0 foot Test hole left open, water level at ground surface after 24 hours. FIGURE 2 z ,t TEST PIT 3 DEPTH -FEET 0.0 - 0.7 Dark brown, organic topsoil (soft, moist) 0.7 - 6.0 Light-brown, silt SAND with some gravel becoming cleaner with depth (loose becoming medium dense, moist) 6.0 - 6.5 Grey, clayey SAND (loose, moist) 6.5 - 13.0 Brown, gravelly SAND with scattered grey, clayey SAND in streaks (medium dense, wet) Light seepage at 8.0 feet j Heavy seepage below 10.0 feet TEST PIT 4 DEPTH - FEET 0.0 - 1.0 Dark brown organic (peaty) topsoil (soft, moist) 1.0 - 1.5 Lense of sand and gravel (loose, moist) 1.5 - 12.0 Grey, clayey silt (soft to medium stiff, wet) No water observed during excavation of test hole FIGURE 3 1 2yq 4 TEST PIT 5 DEPTH - FEET 0.0 - 0.8 Dark brown, organic topsoil (soft, moist) 0.8 - 3.0 Light brown, sandy SILT with trace gravel (soft, moist) 3.0 - 13.0 Brown, silty SAND with some gravel in streaks, gravelly in upper 3 feet (medium dense, moist) i No water observed during excavation of test hole i TEST PIT 6 DEPTH - FEET 0.0 - 1.0 Brown, organic (peaty) topsoil, (soft, moist) 1.0 - 3.0 Light borwn, sandy, clayey SILT (medium stiff, moist to very moist) 3.0 - 12.0 Grey clayey SILT (soft to medium stiff, moist to wet) Light seepage at 2.5 feet FIGURE 4 TEST PIT 7 DEPTH - FEET 0.0 - 3.0 Brown, organic topsoil, peat, wood roots and rotten stumps 3.0 - 5.0 Brown, silty Sand and Gravel (medium dense, moist) 5.0 - 12.0 Grey, clayey, silty SAND with some fine gravel (medium dense, wet) Light to moderate seepage below 5.0 feet Becoming heavy seepage below 10.0 feet FIGURE 5 S APPENDIX 1 PROJECT: Belfair Community Center On May 18, 1983 I logged three holes in the proposed drainfield area (holes 1-3) and three holes in the ballfield drainage area (holes 4-6). The soil logs follow this report. The drainfield area has coarse to medium sand and gravel from three feet to at least seven feet. Due to caving the backhoe was not able to dig deeper. According to DSHS Interim Soil Evaluation Guidelines, the coarse to medium sand would have a percolation rate of 1-5 min./inch and a suggested loading rate of 1.2 GPD/Ft2. This would appear to be the appropriate layer in which to install the drainfield. 3 This layer is overlain with silt loam' and/or fill. Removal of 12 to , 18 inches of this top layer may be desireable to increase areation of the drainfield. The ballfield drainage area in holes 4 and 5 also has sand. The same percolation rates, 1-5 min./inch, and application rate, 1.2 GPD/Ft2. could be used. Hole 6 however has finer sands and loam. According to DSHS, the percolation rates would be 6-15 min./inch and an application rate of 0.75 GPD/Ft2. No soil removal would be necessary. Marjory D. Gouthro, Registered Sanitarian Appendix 1 Page 2 Soil Logs: Hole 1 0-36" Brown silt loam 36"-60" Coarse to medium gray brown sand and gravel 60"-78" Brown sandy loam Hole 2 0-16" Brown sandy loam to silt. This is a mixed layer with some cementing. It may be filled. 16"-18" Organic layer 18"-36" Brown silt loam 36"-84" Coarse to medium gray brown sand and gravel Hole 3 0-14" Brown sandy loam 14"-20" Gray brown medium to coarse sand and gravel 20"-28" Brown sandy loam 28"-48" Gray and brown coarse sand and gravel 48"-72" Fine sandy loam brown 72"-84" Gray and brown coarse sand and gravel Hole 4 0-18" Brown coarse to medium sand and gravel 18"-30" Brown sandy loam with gravel 30"-36" Gray brown coarse to medium sand and gravel 36"-48" Brown sandy loam with gravel 48"-54" Gray brown coarse sand and gravel 45"-108" Brown medium to fine sand with possibly some compaction the last 24" Hole 5 0-12" Brown sandy loam compacted by use 12"-18" Organic decomposed fill 18"-37" Brown coarse sand and gravel 37"-60" Brown medium to fine sand 60"-72" Brown coarse sand and gravel 72"-108" Brown sandy loam Hole 6 0-12" Brown and black loam sand 12"-60". Brown and gray sandy loam 70"-72" Brown coarse to medium sand and gravel 72"-80" Brown fine sand to sandy loam l 80"-84" Gray sand 84"-108" Brown fine sand to sandy loam Water was not found in any of the holes. February 8, 1983 W.O. 8304 LOGS OF TEST PITS Test Pit-1(Completed 2-7-83) 0 - 2' Topsoil 2' - 7' Brown Fine to Medium Sand and Fine to Coarse Gravel , Trace Silt, Moist, Medium Dense Test Pit-2(Completed 2-7-83) 0 - 2k' Fill - Grey Fine to Coarse Sand and Fine to Coarse Gravel , Trace Silt, Loose, Moist 2 Z' - 3 it Topsoil 3?' - 6' Brown Fine to Medium Sand, Little Fine to Coarse Gravel , Trace Silt, Moist, Medium Dense Test Pit-3(Completed 2-7-83) 0 - h' Topsoil ?' - 6�' Brown Fine to Medium Sand, Little Fine to Coarse Gravel , Trace Silt, Moist, Medium Dense Test Pit-4(Completed 2-7-83) 0 - a Topsoil 6h' Brown Fine to Medium Sand and Fine to Coarse Gravel , Trace Silt, Moist to Wet, Medium Dense Free Water @ 6' Test Pit-S(Completed 2-7-83) 0 - 312-' Fill - Topsoil , Silt and Fine Sand, Moist, Loose 33a-' - 81 Brown Fine to Medium Sand, Some Fine to Coarse Gravel , Moist, Medium Dense Test Pit-6(Completed 2-7-83) 0 - 6' Brownish-Grey Fine to Coarse Sand and Fine to Coarse Gravel , Loose, Moist to Wet Free Water @ 3' Grover C.Way, P.E. irwYrvup�hiO-iYYiM1 al�w►l1 ...: .. • • 7 s February 8, 1983 W.O. 8304 LOGS OF TEST PITS(cont) Test Pit-7(Completed 2-7-83) 0 - �2' Grey Fine Sand, Wet, Medium Dense 22' - 412' Brownish-Grey Fine to Coarse Sand and Fine to Coarse Gravel , Wet, Loose 421 - 7' Grey Fine to Coarse Sand and Fine to Coarse Gravel , Wet, Loose Free Water @ 2-1/21 Grover C.Way, P.E. ST4 TF ROUTF n <= 3 SCALE: I"= 100! - 2 TEST PIT NUMBER AND LOCATION. 3 W .�2 Z_ J H Z tiJ o5 a 4 a PE ARtA40� � 7 1 NORTH MASON RECREATION BUILDING Grover C.Way, P.E. SITE PLAN CONSULTING SOILS ENGINEER W.0. 8304 FEBRUARY 1983 PLATE