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Associated Earth Sciences, Inc. Serving the Pacific Northwest Since ig8i November 9, 2011 Project No. KE100287A CITY OF RENTON Renton School District RECEIVED c/o Greene Gasaway, PLLC MAR 0 6 2012 P.O. Box 4158 Federal Way, Washington 98063 BUILDING DIVISION Attention: Mr. Calvin Gasaway Subject: Summary of Additional Borings in Planned Playground Area Early Childhood Learning Center 1800 Index Avenue NE Renton, Washington Dear Mr. Gasaway: This letter summarizes supplementary exploration borings in the proposed new playground area associated with the above-referenced project. This work is supplementary to our earlier work on- site, which has included completion of subsurface explorations and preparation of a geotechnical engineering report dated November 18, 2010, completion of supplementary exploration borings on the north part of the site summarized in a letter dated August 17, 21011, and completion of infiltration rate testing to support site storm water design. This letter should be considered supplementary to our earlier geotechnical engineering report and addenda. BACKGROUND Our earlier subsurface exploration program on-site identified subsurface conditions generally characterized by lodgement till that was typically on the order of 8 to 14 feet thick, underlain by advance outwash sediments that will be used as the storm water receptor. During our initial subsurface exploration program, we identified one location on the north part of the site where existin? fill was present. We later completed a supplementary exploration program on the north part of the site to delineate existing fill, and identified existing fill at several locations ranging up to 8 feet below existing grades. Construction of a new playground complex was recently added to the project. The new playground will occupy portions of-the--existing school site, as well as the adjacent park. The purpose of the additional subsurface explorations summarized in this letter is to provide subsurface information for design of the new playground. The borings also provide additional confirmation Kirkland Everett a Tacoma 425-827-7701 425-259-0522 253-722-2992 www.aesgeo.com ' 8arly Childhood Learning Center Summary of Additional Borings in Renton, Washington Planned Playground Extension to Delineate Existing Fill of the depth to the planned storm water infiltration receptor horizon, which is a valuable confirmation of stratigraphy that affects infiltration system design. ADDITIONAL SUBSURFACE EXPLORATIONS We completed two additional subsurface exploration borings for this phase of work labeled EB-16 and E13-17. Attached with this letter are a "Vicinity Map," Figure 1, showing the site location, and a "Site and Exploration Plan," Figure 2, which depicts all of the explorations completed on- site to date. Logs of the additional subsurface exploration borings completed for this phase of work are also attached. One should refer to our earlier reports for logs of previously completed explorations. In general, the additional exploration borings encountered very dense lodgement till and lodgement till/advance outwash transitional sediments at shallow depths, underlain by advance outwash sediments at depths of approxima e-Iy 13-feet below the group surface. At the location of exp rol ation boring EB-16, the native soils were covered by a layer o exisf ting `ill approximately feet thick. A surficial layer of sod and topsoil was encountered at each of the additional borings completed during this phase, with observed topsoil thickness of approximately 8 inches. CONCLUSIONS AND RECOMMENDATIONS Playground Areas We anticipate that the planned pla roun structure will impose relatively light foundation loads wnw.on the subsurface soils. We recommend that existing play chips, grass, and topsoil be removed from planned construction areas. The area should be excavate to u gra e e evation as needed. Once stripping any required excavation to subgrade elevation has been completed, we recommend that the existing fill be addressed. We recommend that the subgrade be proof-rolled with a loaded dump truck or other suitable equipment. If satisfactory proof-rolling results are observed, no further preparation is necessary, in our opinion. Any soft, rutting, or yielding areas may require additional preparation. Additional preparation will likely include removal and replacement of all or a portion of the yielding materials. Once the recommended site preparation procedures have been completed, we recommend that foundation and fill subgrades be compacted to 95% of the modified Proctor maximum dry density, and to a firm and unyielding condition. Structural Fill, as defined in our comprehensive geotechnical engineering report for the project, may then be placed to raise grades, as needed, to meet project goals. Areas prepared as described may be assumed to support allowable foundation loads of up to 1,500 pounds per square foot (psf) with 1 inch of allowable settlement. Higher November 9, 2011 ASSOCIATED EARTH SCIENCES, INC. BWG/tb-KE100287A9-Projecrs1201002871KEIWP Page 2 ti ' Early Childhood Learning Center Summary of Additional Borings in Renton, Washington Planned Playground Extension to Delineate Existing Fill foundation soil bearing pressures are possible, but are not expected to be needed for the project as proposed. We should be allowed to offer situation-specific recommendations if higher foundation pressures are needed. Play Area Paving Below any playground paving, we recommend completing stripping and excavation to paving subgrade elevation. The resulting surface should be proof-rolled and compacted to 95% of the modified Proctor maximum dry density. Any soft, yielding, or organic areas should receive additional preparation, as dictated by field conditions at the time of construction. The paving sections recommended in our comprehensive geotechnical engineering report can then be constructed as planned. If the pavement areas will not be subjected to wheeled vehicles or maintenance equipment and will be used for playground purposes only, it would be possible to reduce the planned pavement section to 2 inches of Class '/2 inch Hot Mix Asphalt above 4 inches of Crushed Surfacing Top Course if desired. CLOSURE We appreciate the opportunity to submit this letter and hope that it meets your needs. If you have any questions, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Bruce W. Guenzler, L.E.G. Project Geologist K irl V. Merriman, P.E. Principal Engineer Attachments: Figure 1 - Vicinity Map Figure 2 - Site and Exploration Plan Subsurface Exploration Logs EB-16 and EB-17 November 9, 2011 ASSOCIATED EARTH SCIENCES, INC. BWGltb-KE100287A9-Projects 1201002871KEIWP Page 3 i er r, T• a i . ... M. ILI a@ I As J 111 7'y �� I ..� 1•a�f" .�1� 'i � ' I `� �,� � . 1 •. l I� \ Id t�/ 5..`.) 4 / ��/��. !,' 1 � ,\ �., .-� •�•e. , i�'J(r/ �_ li�...+r ; 4• ./.• ' 1Y7 117J J .#' ..• ` r �. �;CGte►i►A�+.•- ,, �`:--�_ . -. ,, � �'•. "I ...Nam\\ \`'\ y � ��.1 ��•• ..�,. nyda L i,� /'S' '••7�� • / • 5- Ke na t' - \, 1. (• ? Park ` %Par {i Pil'�r.t l n' g ' 1'~ � ,, '�,� ',�, r• =:SITE �:�. �>,. :� ti . �►;. _. ri( 5� T N ova 1p41txEl � �r.; •- Powor NE WX�. c. Pk `i t 1 ' 1 • - 1- - r bst� �.• tF I - •r. ti,. +M i No .1- Ho 1 � r la 1 t.1 ► nk• a. j NEI \ 17 �. n I 34 N ;. tip•: I � �'L?!�� I _ % all > f; E Iilgb G Park, ti Seh �M live PH A 8 � a �„-,. I � 'mob,- �► ., Cam'+'m� '� �%'�,.. y 0 1000 2000 '1 REFERENCE: USGS TOPO! FEET a 0 P 9 Associated Earth Sciences, Inc. VICINITY MAP FIGURE 1 EA11/11 E E 1E REN ON, WAS IN R PROJ. NO. DKE100287A T — J ••9 5 T r - r + ^ a ra�. at✓ k rwu+` - B-14 �EB-8 � � -• -9 - EB •� •` k E _ EB-11 EB-13 r♦ - - EB-12 ... , ° ;rf PD-1 EB-3 APPROXIMATE LOCATION S EB-6 ti � OF PIT DRAIN -TYP EB-1/MW-1 EB EB-5 - -' PD-4 INC / PD-2 EB-16 APPROXIMATE LOCATION —/ DEB-17 , OF EXPLORATION BORING -TYP "MW" INDICATE4 MONITORING WELL , YrAw x jk 'F N ON self- REFERENCE: GOOGLE EARTH NO SCALE 0 0 s a s Associated Earth Sciences, Inc. SITE AND EXPLORATION PLAN FIGURE 2 o El El � EARLY CHILDHOOD CENTER DATE 11/11 RENTON, WASHINGTON PROD.NO. KE100287A ° Do° ° Well-graded gravel and Terms Describing Relative Density and Consistency 0N o°o° Gw gravel with sand, little to Densi SPT()blows/foot LL ° Do D no fines Coarse Very Loose 0 to 4 Co a, o 0.0.o Loose 4 to 10 Poorly-graded gravel Grained Soils a0 Lj 05 W pODOOOD GP Medium Dense 10 to 30 Test Symbols o v o p o o o and gravel with sand, Dense 30 to 50 y 0o d o o p o p little to no fines Very Dense >50 G = Grain Size o Z 2 o 2 o 2 tZ) M= Moisture Content z° b o ° D° D Consistency SPT blows/foot A=Atterberg Limits o "' ° GM Silty gravel and Silty Very Soft 0 to 2 C= Chemical o - d ° ° D gravel with sand Fine- Soft 2 to 4 DID= Dry Density Grained Soils c o m ;� Medium Stiff 4 to 8 K= Permeability Stiff 8 to 15 N r Clayey gravel and Very Stiff 15 to 30 m GC clayey gravel with sand Hard >30 0 Component Definitions s o Well-graded sand and Descriptive Term Size Range and Sieve Number o, o SW sand with gravel,little Boulders Larger than 12" to no fines Cobbles 3"to 12" N Gravel 3"to No.4(4.75 mm) m Poorly-graded sand 0 0 > Coarse Gravel 3"to 3/4" C0 L).2 SP and sand with gravel, Fine Gravel 3/4"to No.4(4.75 mm) CD c -r little to no fines c B d jSand No.4 (4.75 mm)to No.200(0.075 mm) Coarse Sand No.4(4.75 mm)to No. 10(2.00 mm) Silty sand and Medium Sand No.10(2.00 mm)to No.40(0.425 mm) �N SM Silty sand with Fine Sand No.40(0.425 mm)to No.200(0.075 mm) U oho° 0 i gravel Silt and Clay Smaller than No.200(0.075 mm) u) cSC Clayey sand and (3)Estimated Percentage Moisture Content ,� clayey sand with gravel Percentage by Dry-Absence of moisture, U) Component Weight dusty,dry to the touch Silt, sandy silt, gravelly silt, Trace <5 Slightly Moist-Perceptible > o ML silt with sand or gravel Few 5 to 10 moisture Little 15 to 25 Moist-Damp but no visible in T With Non-primary coarse water N v N Clay of low to medium constituents: > 15% Very Moist-Water visible but d CL plasticity; silty, Sandy,or Fines content between not free draining Z = gravelly clay, lean clay 5%and 15% Wet-Vislble free water,usually Ivcn-1 from below water table Organic clay or silt of low Symbols _— oL plasticity Blows/6"or �° Sampler portion of 6" — — Cement grout Type / surface seal ° Elastic silt,clayey sit, silt ` Sampler Type 2.0"OD Bentonite MH with micaceous or Split-Spoon A Description o Bm (A) seal o diatomaceous fine sand or Sampler y w� Silt p 3.0'OD Split-Spoon Sampler - • ;, Filter pack with `o (SPA 3.25"OD Split-Spoon Ring Sampler tq � •� blank casing � v o Clay of high plasticity, •: section CH sandy or gravelly Clay,fat Bulk sample 3.0'OD Thin-Wall Tube Sampler Screened casing clay with sand or gravel (including Shelby tube) or Hydrotip Grab Sample with filter pack i-n 4 Organic clay or silt of o Portion not recovered End cep LL OH medium to high (1) Percentage by dry weigh (4) Depth of round water plasticity t�1 (SPT)Standard Penetration Test P g (ASTM D-1586) 1 ATD=At time of drilling �,•E m Peat, muck and other (3) In General Accordance with '�Z Static water level(date) m m N PT highly Organic soils Standard Practice for Description ts) Combined USCS symbols used for _ and Identification of Soils(ASTM D-2488) fines between 5%and 15% JClassifications of soils in this report are based on visual field and/or laboratory observations,which Include density/consistency,moisture condlbon,grain size,and plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein.Visual-manual and/or laboratory classification o methods of ASTM D-2487 and D-2488 were used as an identification guide for the Untried Soli Classification System. Y g Associated Earth Sciences, Inc. x 0 li N a 0 d EXPLORATION LOG KEY FIGURE Al Associated Earth Sciences,Inc. Exploration Log ay, Project Number Exploration Number Sheet " KE100287A EB-16 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 1(1/gs/11 16/9R/11 Hammer Weight/Drop 140#13011 Hole Diameter(in) 9 inrhpg , ` y Blows/Foot s a a�� �E o iu o T o7 0 m L DESCRIPTION 3 10 20 30 40 ° Grass 8 inches. Hand dug 2 feet. Fill Loose,very moist,mottled brown,fine to medium SAND,little silt,little fine 7 S-1 gravel(SM). 3 A6 --—————————— ————— ——---- - 3 Lodgement Till 5 Very dense,very moist,mottled gray,fine to coarse SAND,with silt and 18 S-2 fine gravel(SM). 31 A 675 44 10 Becoming gray with less mottling. 18 S-3 25 A 652 27 Advance Outwash 15 Very dense,moist,gray,fine SAND,few silt and fine gravel(SP). 25 S-4 Gradational stratification. 27 A 657 30 Bottom of exploration boring at 17 feet 20 25 30 35 b , N �y L E 0 z EL EL 0- I I I I -L Sampler Type(ST): 8 m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG m m 3"OD Split Spoon Sampler(D&M) Ring Sample SZ Water Level() Approved by: w ® Grab Sample ® Shelby Tube Sample 1 Water Level at time of drilling(ATD) Associated Earth Sciences,Inc. Exploration Log El ; „ Project Number Exploration Number Sheet El El U KE100287A EB-17 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 1 n/28/11 1012R/11 Hammer Weight/Drop 140#/30" Hole Diameter(in) R inrhas cn > �p rn r n o — y Blows/Foot a S E �� �E o m m _ T DESCRIPTION " m 10 20 30 40 ° Grass and topsoil 8 inches. Hand dug 2 feet. Lodgement Till/Advance Outwash Transitional Sediments Dense,moist,brownish gray,fine to medium SAND,few silt,few fine 16 S-1 gravel(SP). 20 39 19 5 Very dense,moist,fine to coarse SAND,little to with silt(varies),little fine 40 S-2 gravel(SP-SM). Gradational stratification. 0/ " 50/ " 10 Dense,very moist,gray,fine to coarse SAND,with silt to few silt(varies), 12 S-3 little fine gravel. 16 A 49 33 Advance Outwash 15 Very dense,moist,gray,fine SAND,few silt,trace fine gravel(SP). 19 S-4 27 A L64 37 Bottom of exploration boring at 17 feet 20 25 30 35 b N 1� E 0 z a c� Sampler Type(ST): S m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG m m 3"OD Split Spoon Sampler(D&M) Ring Sample Q Water Level() Approved by: a ® Grab Sample ® Shelby Tube Sample 1 Water Level at time of drilling(ATD) Associated Earth Sciences, Inc. ad } NJ W] 0 Ce[W rabn Over25 Vean o f Yemee August 17, 2011 Project No. KE100287A Renton School District c/o Greene Gasaway, PLLC P.O. Box 4158 Federal Way, Washington 98063 Attention: Mr. Calvin Gasaway Subject: Summary of Additional Borings to Delineate Existing Fill Early Childhood Learning Center 1800 Index Avenue NE Renton, Washington Dear Mr. Gasaway: This letter summarizes supplementary exploration borings to delineate existing fill on the northeast portion of the site. This work is supplementary to our earlier work on-site, which has included completion of subsurface explorations and preparation of a geotechnical engineering report dated November 18, 2010. This letter should be considered supplementary to our earlier geotechnical engineering report. BACKGROUND Our earlier subsurface exploration program on-site identified subsurface conditions generally characterized by lodgement till that was typically on the order of 8 to 14 feet thick, underlain by advance outwash sediments that would be used as the storm water receptor. One boring, EB-7, identified existing fill to a depth of approximately 7 feet above the native sediments on the northeast part of the site. Review of available historic information showed that the northeast portion of the site had previously been occupied by houses that were demolished. We speculated that existing fill observed at EB-7 may have been related to the previous houses in this area. We proposed to complete additional subsurface explorations in the vicinity of EB-7 to further explore the limits of the existing fill. This report summarizes the results of those additional exploration borings. ADDITIONAL SUBSURFACE EXPLORATIONS We completed a total of eight additional subsurface exploration borings. Attached with this letter are a "Vicinity Map," Figure 1, showing the site location; a "Site and Exploration Plan," Figure 2, which depicts all of the explorations completed on-site to date; and "Enlarged Site and Kirkland Everett Tacoma 425-827-7701 425-259-0522 253-722-2992 www.aesgeo.com Early Childhood Learning Center Renton, Washington Summary of Additional Borings to Delineate Existing Fill Exploration Plan," Figure 3, which depicts explorations in the vicinity of EB-7 at a larger scale. Figure 3 also displays the depth of observed existing fill at each exploration boring location. In general, the additional exploration borings identified an area of existing fill that extends north and south of EB-7. The existing fill appears to extend beyond the limits of the previously existing houses in this area, and therefore may not be directly related to the previous residential development. In general, the existing fill is of similar gradation and appearance as the native site soils, but is looser. Our exploration borings did not encounter substantial quantities of deleterious materials such as organic material or demolition waste in the existing fill. Detailed descriptions of the conditions observed in each exploration boring are included on the interpretive subsurface exploration logs included with this letter. CONCLUSIONS AND RECOMMENDATIONS We do not recommend that new foundations be constructed above existing fill. We recommend that below foundation elements the existing fill be removed, and the planned foundation grade restored, as needed, with structural fill as defined in our earlier geotechnical engineering report. New foundations can then be constructed with an allowable foundation soil bearing pressure of 3,000 pounds per square foot (psf) above the new structural fill. If desired, slab-on-grade floors may be underlain by existing fill capped with 2 feet of new structural fill. If this approach is selected, we recommend that the existing fill be excavated as needed to allow placement of at least 2 feet of new structural fill below the planned floor and capillary break materials. The resulting surface should be proof-rolled and compacted to 95% of the modified Proctor maximum dry density. Any soft, yielding, organic, or otherwise unsuitable soils should receive additional preparation as dictated by field conditions at the time of construction. Following subgrade preparation, 2 feet of new structural fill should be placed. This approach will result in floor slabs constructed above existing fill. This approach will result in cost savings as compared to removing all of the existing fill as previously described for areas below new foundations, and will also result in risk of some additional floor slab settlement if undetected unsuitable fill remains below the floors. This risk is difficult to quantify, and settlement of floor slabs in the finished building could be challenging to repair. If the risks of larger than normal floor slab settlement are not acceptable, all existing fill should be removed from below floor slabs. Below paving, we recommend completing stripping and excavation to paving subgrade elevation. The resulting surface should be proof-rolled and compacted to 95% of the modified Proctor maximum dry density. Any soft, yielding, or organic areas should receive additional preparation, as dictated by field conditions at the time of construction. The paving sections recommended in our comprehensive geotechnical engineering report can then be constructed as planned. This approach will result in considerable cost savings as compared to removing all of the existing fill below paving, but will result in somewhat higher risks of paving settlement. Paving areas are generally easier and less expensive to repair than previously described for floor slabs. If the August 17, 2011 ASSOCIATED EARTH SCIENCES, INC. KDM11b-KE100287A5-Projeas1201002871KE1 WP Page 2 Early Childhood Learning Center Renton, Washington Summary of Additional Borings to Delineate Existing Fill potential for larger than normal total and differential settlement of paving areas is unacceptable, all existing fill should be removed from below planned paving. Below grade sensitive buried utilities, such as gravity drains, we recommend that at least 1 foot of the existing fill be removed. The subgrade should be proof-rolled and compacted to 95% of the modified Proctor maximum dry density. Any soft, yielding, or organic areas should receive additional preparation as dictated by field conditions at the time of construction. One foot of new structural fill should be placed to reach planned grade for pipe bedding materials. This approach will result in some additional risk of settlement as compared to removal of all of the existing fill. It may be appropriate to increase drainage gradients of utilities constructed above existing fills such that some settlement can be tolerated while still maintaining planned flow directions and positive gradients in the pipes. CLOSURE We appreciate the opportunity to submit this proposal and hope that it meets your needs. If you have any questions, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington Kurt D. Merriman, P.E. Principal Engineer Attachments: Figure 1 - Vicinity Map Figure 2 - Site and Exploration Plan Figure 3 - Enlarged Site and Exploration Plan Subsurface Exploration Logs August 17, 2011 ASSOCIATED EARTH SCIENCES, INC. KDM1tb-KE100287A5-Projects 1201002871KE1 WP Page 3 p+/ ��•' 4 w f"11 Coleman i - w Pdint _ ay r tee` ► e_ r rry i ides a r rN .97 ,, _ rllralra+ t• 7'F Park ''ti �' Pa FT ' e ' GON 3 SITE A', •.`�pit I�•� � �„ .w ' L _»i�; `�..... T N Park a.•q��+y a •+ F ower ER t VOO— tank• Rya ; 4 li �. M AL Alp , ' � sill n / Park. Mi liver � �� Pit 11 1 a V (�3 0 1000 20W VREFERENCE: USGS TOPOI FEET 4 Associated Earth Sciences, Inc. VICINITY MAP FIGURE 1 41 W EARLY CHILDHOOD CENTER DATE 7/11 9 El El El KI IF4A'0 RENTON, WASHINGTON PROJ.NO. KE100287A (h h t i 1 a� " I'I I ' . w ' m, LLl u ,s N REFERENCE: GOOGLE EARTH NO SCALE S z s s Associated Earth Sciences,Inc. SITE AND EXPLORATION PLAN FIGURE 2 W EARLY CHILDHOOD CENTER DATE 7/11 g RENTON, WASHINGTON PROD.NO. KE100287A j 'c I y rt10:(D' N i I Z i 9 . fKVff"I•P xD.E m { 99 �no.7� I w I 1C I OV \ �- KYW� x.1fJ la 3e_x.l'.1.y1'L777.ST itl i-t O APPROXIMATE LOCATION OF EXPLORATION BORING ', ;� •- i \ WITH DEPTH OF OBSERVED FILL F -TYP t ` EB-8 ' 0' d v l r� EB-9* �� \ 8 B-14i% 0, EB-7 I \< 7, EB-10 8° \o i �ePP EB-15 0, 0 EB-11 51 � :fIN 2•tW55[RI•an � '( \ /////lam%�' PtMal N 1Y1'C.1h111[ �TVx \ `� • L rFfY a vsr� / 01 EB-12 , 00 s. > EB-3 0 ron+4.14cww: i a ^ o 05 F I A 0 50 too a REFERENCE: GOOGLE EARTH FEET L z Associated Earth Sciences, Inc. ENLARGED SITE AND EXPLORATION PLAN FIGURE 3 W EARLY CHILDHOOD CENTER DATE 8/11 - K RENTON, WASHINGTON PROJ.NO. KE100287A Associated Earth Sciences,Inc. _ Geolo ie & Monitoring Well Construction Log � -.� Project Number Well Number Sheet r' '��'a -- 1,,�. KE100287A EB-1 1 1 of 2 Project Name Early Childhood Center Location Renton. WA Elevation(Top of Well Casing) N/A Surface Elevation(ft) Water Level Elevation Date Start/Finish 11/....... 1 fl 1 1/1 1/10 Drilling/Equipment Boretec/Track _ Hole Diameter(in) 7 inches Hammer Weight/Drop 140#/30" t > U a°i J 3` m'E Q p f0 T WELL CONSTRUCTION T m N DESCRIPTION Flush monument Grass and topsoil. — Concrete 2 to 0 feet Lodgement Till Hand dug to 2 1/2 feet. 10 18 inches recovery. Dense,very moist,mottled,gray and brown, 12 fine to coarse SAND,little silt,little fine gravel(SW-SM). No 18 stratification or structure. r 5 Bentonite chips 47 to 2 feet 8 18 inches recovery. Becomes medium dense,mottled brown f12 Subtle gradational stratification. F 16 Advance Outwash 10 1 1/4-inch PVC blank to 20 18 inches recovery. Very dense,very moist,brown•fine to coarse surface 33 SAND,little to with silt,little fine gravel(SM)- 30 —15 20 18 inches recovery. Very dense,moist,brownish gray,fine SAND, 32 few silt Subtle gradational stratification(SP). 38 20 35 18 inches recovery Grades with trace fine gravel 34 29 $ Weak seepage zone(perched) 25 18 18 inches recovery. Very dense,moist to wet(varies),gray,fine to 32 coarse SAND,few sill,interbedded with brown,fine SAND,with silt 50 (SP with SM). Weak seepage above brown,fine sand 30 28 18 inches recovery Very dense,moist,gray,fine to medium SAND, 35 trace to few silt(SP). 43 0 35 28 As above 35 0 28 z o >: c7 Sampler Type(ST): 8 m 2"OD Split Spoon Sampler(SPT) 0 No Recovery M - Moisture Logged by: BWG Y OD Split Spoon Sampler(D&M) ® Ring Sample Q Water Level() Approved by: Grah Sample Shelby Tube Sample T Water Level at time of drilling(ATD) -Associated Earth Sciences,Inc. Geologic & Monitoring Well Construction Lo Project Number Well Number beet r' KE100287A EB-1 1 2 of 2 Project Name Early Childhood Center Location Renton, WA Elevation(Top of Well Casing) N/A Surface Elevation(fl) Water Level Elevation Dale Start/Finish 1 11 nch/1 1/1 O1 1/1 1/1 n Drilling/Equipment Boretec/Track Hole Diameter(in) 7 ies _ Hammer WeighUDrop 140#/30" > U O y o in m E � � T WELL CONSTRUCTION T DESCRIPTION 34 18 inches recovery Trace fine gravel concentrated in zones 1-inch 38 thick. 45 i `15 28 18 inches recovery Trace gravel becomes more evenly distributed. 35 38 f Colorado#10-20 60 to 47 feet 50 - Zq 18 inches recovery. Grades without gravel 1 1/4-inch PVC screen 5p 0.020-inch slot 60 to 50 feet 55 26 18 inches recovery as above _ at 60 P8 18 inches recovery. Gradation as above Well Tag#BBB 965 32 34 Boring terminated at-6-1 1/2 feel on 11/11l10 I 65 70 I Rs 75 C3 0 U z, a 0 m c� Sampler Type(ST): 0 2"OD Split Spoon Sampler(SPT) No Recovery M - Moisture Logged by: BWG 3"OD Split Spoon Sampler(D&M) Ring Sample Water Level() Approved by: S y ® Grab Sample Q Shelby Tube Sample Water Level at time of drilling(ATD) Associated Earth Sciences,Inc. Exploration Log �1 Project Number Exploration Number Sheet Y" * '" KE100287A EB-2 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton. WA — Datum -N/A Driller/Equipment Boretec/Track Date Start/Finish 1 1/1 1/10 1 1/1 1/10 Hammer Weight/Drop _140#/30" _ Hole Diameter(in) 7 inrhpG C� >O - ul tD a C° v a� N Blows/Foot a S E mT �E � o u T rn U rn U m m r DESCRIPTION 10 20 30 40 ° Grass and topsoil. Lodgement Till Hand dug to 2 feet. - 18 inches recovery Dense,moist,mottled,gray,jfine to coarse SAND 13 S-1 with silt,little fine gravel(SM). No stratification- � 17 A34 17 5 S 2 18 inches recovery Gradation as above 13 22 4 27 10 10 inches recovery Becoming gray and less motlled 16 S-3 35 So/ :or Advance Outwash 15 18 inches recovery. Dense,moist,brownish gray,fine SAND,little fine 13 S-4 gravel and silt(SM) Gradational stratification 15 �3 20 i - 20 18 inches recovery Very dense,moist,gray,fine SAND,few silt(SP). No 18 S-5 stratification 25 55 ----— -- ---- _. ------ - - 30 Bottom of exploration boring at 21 112 feet i — 25 30 I I � 0 35 0 ri e7 si a E w. u � I D Sampler Type(ST): 8 0 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o m 3"OD Split Spoon Sampler(D&M) D Ring Sample Q Water Level() Approved by: m in © Grab Sample 0 Shelby Tube Sample 1 Water Level at time of drilling(ATD) Associated Earth Sciences, Inc. Exploration Log y Project Number Exploration Number Sheet 10 <;, l-J E J�• KE100287A EB-3 1 of 1 Project Name Early Childhood Center — Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment BOreteC/Track _ DateStart/Finish 11/11/11111/11/10 Hammer Weight/Drop 140#/30" Hole Diameter(in) 7 inrhps O > ' y Blows/Foot y S E 25, E� o Q rn T `� DESCRIPTION 0 m t 10 20 30 40 0 2 inches asphalt paving Lodgement TIII 18 inches recovery Very dense,moist,mottled,gray,fine to coarse 24 S-1 SAND,little fine gravel(SM). No stratification 38 AL72 36 5 18 inches recovery Gradation as above. Becoming brown. 17 S-2 57 27 30 I - - 10 18 inches recovery. Very dense,moist,gray,fine to medium SAND,few 14 S-3 fine gravel,trace sill(SP). No stratification 26 64 38 (Weak seepage zone) 15 Very dense,very moist to wet,brown,fine SAND,with silt(SM) No t7 S-4 stratification 27 JL54 27 20 Very dense,moist,gray,fine to medium SAND,trace silt and fine gravel 17 S-5 (SP) No stratification 24 51 --- -- —---- -- ---- .._ 27 Bottom of exploration boring at 21 1/2 feet 25 i 30 i 0 35 0 N N n E v U Z a' c� m Sampler Type(ST). Q 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o [D Y OD Split Spoon Sampler(D&M) Ring Sample 1Z Water Level() Approved by: w 0 Grab Sample 0 Shelby Tube Sample T Water Level at time of drilling(ATD) a Associated Earth Sciences,Inc. Exploration Log a (—, V Project Number Exploration Number Sheet Ed �' I<E100287A EB-4 1 of 1 _ Project Name Early Childhood Center Ground Surface Elevation(ft) NIA Location Renton, WA Datum N/A Driller/Equipment Boretec/Track __ Date Start/Finish 1 1/11/10'1 1/1 1/10 Hammer Weight/Drop 1404/30" Hole Diameter(in) 7 i=hr'S a a� Z Blows/Foot a S E 12r 3Ev o w DESCRIPTION 09 10 20 30 40 0 1 1/2 inches asphalt paving. Lodgement Till 18 inches recovery Very dense,moist,brown,fine to coarse SAND,with 22 S-1 silt,little fine to coarse gravel(SM). No stratification 38 88 50 5 S-2 2 Inches recovery. Blowcount overstated Gradation as above based on 01E 504 I I recovery and cuttings i ; i I I 10 18 inches recovery Grades to with fine to coarse gravel(SM). 12 S-3 32 72 40 Advance Outwash 29 15 S-4 18 inches recovery. Very dense,moist,brown,fine SAND,few silt,trace fine gravel(SP). Gradational s(ralificatlon,primarily of gravel fra 40ction 40 80 40 ll 20 18 inches recovery To 21 feet gradation as above. Below 21 feet dense, ig S-5 moist,gray,fine to medium SAND,trace silt(SP). 22 -•----- — ._...._..-------- —.. 25 Bottom of exploration boring at 21 1/2 feet - 25 i i - 30 0 35 o i I U' n E 0 2' � � '-J Sampler Type(ST) 8 mmm 2"OD Split Spoon Sampler(SPT) Q No Recovery M-Moisture Logged by: BWG o L1J Y OD Split Spoon Sampler(D&M) Ring Sample Water Level() Approved by: m © Grab Sample © Shelby Tube Sample Water Level at time of drilling(ATD) C Associated Earth Sciences,Inc Exploration Log (� El � � �'ti�� Project Number Exploration Number Sheet u KE100287A EB-5 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton. WA _ Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 11/11110 11111/1n Hammer Weight/Drop 140#/30" Hole Diameter(in) 7 inrbps c a� a a� �, H Blows/Foot r a S E 2T �E°: o u T N 0 rn o m L DESCRIPTION " 10 20 30 40 Grass and topsoil• _ Lodgement Till 14 inches recovery Very dense,moist,mottled,brown,fine to coarse i t S-1 SAND,with silt and fine to coarse gravel(SM). No stratification 29 62 33 18 inches recovery Gradation as above 16 S-2 30 72 42 Advance Outwash 10 18 inches recovery Very dense,moist,brown,fine SAND,few silt(SP). 15 S 3 Significant gradational stratification 26 55 29 15 18 inches recovery. Gradation as above,but without stratification. 13 S 4 21 �4 25 - 20 18 inches recovery. As above 16 S•5 23 AL52 29 Bottom of exploration boring at 21 1/2 feet 25 30 0 35 0 n e v v' a. Sampler Type(ST): m 2"OD Split Spoon Sampler(SPT) 0 No Recovery M-Moisture Logged by: BWG o 3"OD Split Spoon Sampler(D&M) 1] Ring Sample Q Water Level() Approved by: Grab Sample Z Shelby Tube Sample Water Level at time of drilling(ATD) Associated Earth Sciences,Inc. _ Exploration Log Project Number Exploration Number Sheet f KE100287A EB-G F1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 11/1 1/10 11/11/10 Hammer Weighl/Drop 140#!30" Hole Diameter(in) 7 inrhac N U ° o (131D Blows/Foot 1 N N t a -N J fi 5 E w T E m o u o T Vm) rn ° m t DESCRIPTION " 10 20 30 40 ° Grass and lopsoiL _ Lodgement Till 18 inches recovery. Dense,moist,mottled,brown,fine to coarse SAND, 13 S-1 with sill,little fine to coarse gravel(SM)- No stratification. 13 30 17 5 S 2 18 inches recovery. Gradation as above 21 A42 21 10 Advance Outwash --- - - - - - 18 inches recovery. Dense,very moist,brown,fine SAND,few silt-silt 14 S"3 stringer 11 to 11 2 feet(SP with ML). 24 �n3 i 19 - 15 18 inches recovery Becomes very dense Grades with trace fine gravel 22 S-4 Significant stratification(SP) 40 AL87 47 20 18 inches recovery Gradation as above,but minimal stratification(SP). 18 S 5 24 5a - 30 i Bottom of exploration boring at 21 1/2 feet 25 30 I I i i 0 35 0 N N E 41 Z Sampler Type(ST): $ m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG m 3"OD Split Spoon Sampler(D&M) Ring Sample Water Level 0 Approved by: N Grab Sample Shelby Tube Sample p Water Level at time of drilling(ATD) Associated Earth Sciences,Inc. Exploration Log _ i. Project Number Exploration Number Sheet KE100287A EB-7 _ 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) Nam__ Location Renton WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 1 1/1 1/10 1 1/11/1 n Hammer Weight/Drop 140#/30" — Hole Diameter(in) 7 in hp..; C > _ JP 0. a� -J N Blows/Foot . S E mE, �E� o u T m �N Ulm � DESCRIPTION 10 20 30 40 O Grass and topsoil. _ ------ ---- --- .. ...... Fill 14 inches recovery. Loose,very moist,brown,fine SAND,with silt,few 6 S-1 fine gravel(SM). 3 A 4 5 6 inches recovery Gradation as above 3 S-2 9 4 5 i Advance Outwash � i 10 18 inches recovery. Dense,moist,brown,fine SAND,few silt,trace fine 9 S-3 gravel(SP) Gradational stratification 14 30 16 i - 15 6 inches recovery. Disturbed cuttings resemble S-3. 10 S-4 23 53 36 i 20 No recovery. 9 S-5 17 A34 t7 Dense,moist,gray,fine SAND,few silt(SP) No stratification- 9 S-6 14 '3 —.----.....—...... _.-__- - -----...... 21 25 Bottom of exploration boring at 24 feel I i .30 I 0 35 0 ry a c o �a7 n Sampler Type(ST): 8 m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o [0 Y OD Split Spoon Sampler(D&M) Ring Sample SZ Water Level() Approved by: w © Grab Sample Q Shelby Tube Sample 1 Water Level at time of drilling(ATD) a ASSnCidtCll 1-Mil,;CiQnl'CS,Inc. Exploration Lo Project Number Exploration Number Sheet KE100287A EB-8 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 7/24/11 Hammer Weight/Drop 140#/30" Hole Diameter(in) rn U O .O N Zo N t a o M =a� 3 N Blows/Foot m E a � 3 � S @ 5, �E o a) T 75 m DESCRIPTION " 10 20 30 40 ° _Grass and topsoil 5 inches._ Lodgement Till Hand dug 1 112 feet Medium dense,very moist,light brown,fine SAND,with silt,little fine gravel(SM). 10 S-1 Very dense,moist,light brown with mottling,fine to medium SAND,with 14 A660 silt,little fine to coarse gravel(SM);no stratification 41 5 Very dense,moist,gray,fine to coarse SAND,with silt,few fine to coarse 20 S-2 gravel(SM);no stratification. 41 A L50/!" Bottom of exploration boring at 6 112 feet 10 15 20 25 30 35 0 N N Q a c9 a Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) ❑ No Recovery M-Moisture Logged by: BWG m m 3"OD Split Spoon Sampler(D&M) 11 Ring Sample SZ Water Level() Approved by: w ® Grab Sample © Shelby Tube Sample 1 Water Level at time of drilling(ATD) a Associated Earth Sciences, Inc. Exploration Log Project Number Exploration Number Sheet 0 lK�] r-;k KE100287A EB-9 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton,WA Datum NIA Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 7124111 Hammer Weight/Drop 140#/30" Hole Diameter(in) C N .N. VN U— .O > = 10 — - Blows/Foot a S E 12 T E a o T � 0 rn o m co c DESCRIPTION `' 10 20 30 40 ° S 1 Grass and topsoil. g Lodgement Till to 19 Medium dense,moist,light brown,fine SAND,with silt,few fine gravel 9 (SM);no stratification. Dense,moist,brown,fine to medium SAND,with silt(SM) 15 S-2 19 49 30 5 Very dense,moist,gray,fine to coarse SAND,with silt,little fine gravel 25 S-3 (SM);no stratification Sample smeared with material from above. 38 50/ " Advance Outwash Cuttings become gray,with less silt. 10 Very dense,moist,gray,fine to medium SAND,few to little silt(varies),few 15 S-4 fine gravel(SP-SW);gradational stratification. 24 A653 --- - .._...--------- --- _ 29 Bottom of exploration boring at 11 1/2 feel 15 20 25 30 35 0 N N J J Q a Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) O No Recovery M-Moisture Logged by: BWG o m 3"OD Split Spoon Sampler(D&M) 11 Ring Sample Q Water Level() Approved by: m w ® Grab Sample Z Shelby Tube Sample t Water Level at time of drilling(ATD) a Associated Faith sciences, Inc. Exploration Log k',� Project Number Exploration Number Sheet L�� KE100287A EB-10 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum NIA Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 7/24/11 Hammer Weight/Drop 140#130" Hole Diameter(in) c Z (q U- O > - fA o a� aU— BIOWS/FOOL a S E 2 T E o iv o o 4-1 ° T to coDESCRIPTION 0 10 20 30 40 ° _Grass and topsoil. 5 S-1 __ _ __- Fill 7 Al2 Medium dense,moist,light brown,fine SAND,little to with silt,trace coarse 5 sand/fine gravel,trace organic(topsoil)(SM) S-2 8 7 19 12 5 Loose,moist,light brown,fine SAND,with silt,few fine gravel/coarse sand, 3 S 3 trace organic(topsoil)(SM). 2 9 7 Advance Outwash 10 Dense,moist,brown,fine SAND,few silt,trace fine gravel/coarse sand 9 S-4 (SP);no stratification. 13 A2 13 15 S 5 Becomes very moist,with thin(1/4-inch)silty stringers(SP) 12 . 12 2 13 Bottom of exploration boring at 16 1/2 feet 20 25 30 35 S N N J m J Q 'a 0 m Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o Y OD Split Spoon Sampler(D&M) U Ring Sample Q Water Level() Approved by: 5 Grab Sample ® Shelby Tube Sample i Water Level at time of drilling(ATD) Associated Earth Sciences, Inc. Exploration Log <. Project Number Exploration Number Sheet t' E� KE100287A EB-11 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7124/11,7/24/11 Hammer Weight/Drop 140#/30" Hole Diameter(in) c a> N N L2 a) G� N J to Blows/Foot a S E m >, �E8o ai o T C7 rn o CU m L DESCRIPTION 3: 10 20 30 40 ° Grass and topsoil _ _ 6 S-1 Flll _ 8 ♦14 Medium dense,moist,mixed brown and gray,fine to coarse SAND,with 6 silt,few fine gravel(SM). Loose,moist,brown and dark brown,fine SAND,few to little silt,trace fine 5 S-2 gravel(SP-SM). 5 9 4 5 Lodgement Till S-3 Dense,moist,gray,fine to coarse SAND,with silt,little fine gravel(SM);no 9 stratification. 17 40 23 Smoother drilling. 10 Becomes very dense. 28 S-4 0/ " 78 Bottom of exploration boring at 11 feet 15 20 25 30 35 RN N J OI 7 a a t7 Sampler Type(ST): S m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o 3"OD Split Spoon Sampler(D&M) U Ring Sample SZ Water Level() Approved by: w ® Grab Sample ® Shelby Tube Sample 1 Water Level at time of drilling(ATD) a a t ASSOClated Earth sciences,Inc. Exploration Log r- t'' s.,✓ r Project Number Exploration Number Sheet - r� KE100287A EB-12 1 of 1 Project Name Early Childhood Center _ Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 7/24/1 1 Hammer Weight/Drop 140#/30" Hole Diameter(in) d U N N r n nr ID a) -r N Blows/Foot o� T rn Ov' �o mm r DESCRIPTION 10 20 30 40 ° _Grass and topsoil. 4 S-1 Lodgement Till 7 A 12 5 Very dense,moist,gray,fine to medium SAND,with silt,few fine gravel 12 S-2 (SM);no stratification 16 AL66 50 5 Advance Outwash S-3 Very dense,moist,gray,fine SAND,few silt,trace coarse sand/fine gravel 28 (SP). 40 A L50/," OP" Bottom of exploration boring at 6 112 feet 10 15 20 25 30 35 R N J J a a' c7 Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o 3"OD Split Spoon Sampler(D&M) U Ring Sample Water Level() Approved by: w ® Grab Sample © Shelby Tube Sample t Water Level at time of drilling(ATD) a Associated Eat Ili Sciences,Inc. Exploration Log E1y`Y'i: �—];� Project Number Exploration Number Sheet , KZ 0 KE100287A EB-13 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton, WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 704/11 Hammer Weight/Drop 140#/30" Hole Diameter(in) m =0 4 min m o S E E ° a 3 BIOWS/FOOL m � _o a T DESCRIPTION " m 10 20 30 40 ° S 1 Grass and topsoil. __ 6 Lodgement Till - - 10 A2 Medium dense,moist,brown,fine to coarse SAND,with silt,little fine 15 gravel(SM). i S 2 Advance Outwash 12 Dense,moist,gray,fine SAND,few silt,trace coarse sand/fine gravel(SP); 24 8 gradational stratification. 24 5 Grades with little silt. Gradational stratification. 29 S-3 0/ " 79 Bottom of exploration boring at 6 feet 10 i 15 20 25 30 35 R a a c7 m Sampler Type(ST): 0 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: gV`/G m Y OD Split Spoon Sampler(D&M) Ring Sample SZ Water Level() Approved by: ® Grab Sample 0 Shelby Tube Sample 1 Water Level at time of drilling(ATD) w Associated Faith sciences,Inc. Exploration Log a Project Number Exploration Number Sheet _ t+ K' E� KE100287A EB-14 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton,WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7/24/11 704/11 Hammer Weight/Drop 140#/30" Hole Diameter(in) g > � � L a 4 � Z Blows/Foot S m 10T �E� o a T `� °u) DESCRIPTION " 310 10 20 30 40 ° S 1 Grass and topsoil. 5 Fill 1 1 AL20 Medium dense,moist,light brown,fine SAND,with silt,few fine gravel 9 (SM). S 2 Loose,moist,brown,fine SAND,with silt,trace fine gravel(SM) g . 4 5 1 5 Loose,moist,gray,fine SAND,few silt,few coarse sand/fine gravel(SP). 4 S-3 4 9 5 Advance Outwash 10 Very dense,moist,gray,fine SAND,few silt and fine gravel(SP). 35 S 4 _ 0/ 501 ,. Bottom of exploration boring at 11 feet 15 20 25 30 35 0 N Yl J m J Q a C� m Sampler Type(ST): m 2"OD Split Spoon Sampler(SPT) F1 No Recovery M-Moisture Logged by: BWG o [D Y OD Split Spoon Sampler(D&M) 1] Ring Sample SZ Water Level() Approved by: a ® Grab Sample ® Shelby Tube Sample 1 Water Level at time of drilling(ATD) Associated Faith Science,, Inc. Exploration Log e f YI Project Number Exploration Number Sheet KE100287A EB-15T 1 of 1 Project Name Early Childhood Center Ground Surface Elevation(ft) N/A Location Renton,WA Datum N/A Driller/Equipment Boretec/Track Date Start/Finish 7/24/1 1 7124111 Hammer Weight/Drop 140#/30" Hole Diameter(in) N L N y fN —m J N Blows/Foot a S E m T E o v p T � CD rn o m m t DESCRIPTION " 3: 10 20 30 40 ° Grass and topsoil. 5 S-1 Lodgement Till _- _. _ _ _ 10 A2 Medium dense,moist,brown,fine to medium SAND,with silt,few fine 15 gravel(SM). Becomes dense,brownish gray. 14 S-2 14 A34 20 5 S-3 Becomes very dense. 20 0/ Bottom of exploration boring at 6 feet 10 15 20 25 30 35 0 N N 7l J J Q a C7 m Sampler Type(ST): o m 2"OD Split Spoon Sampler(SPT) No Recovery M-Moisture Logged by: BWG o m 3"OD Split Spoon Sampler(D&M) Ring Sample SZ Water Level() Approved by: co ® Grab Sample 0 Shelby Tube Sample 1 Water Level at time of drilling(ATD) WASHINGTON STATE DEPARTMENT OF ECOLOGY WATER QUALITY PROGRAM PROGRESS REPORT FORM Funding Source: ❑ 319 ❑ Centennial ❑ DIF ❑ Revolving Fund ❑ Reclaimed Water ® Stormwater Grant/Contract/Loan Number: G1200545 Project Title: Harrington Avenue NE Green Connection Project Period: July 1, 2012— September 30, 2015 Recipient Organization: City of Renton Recipient Project Manager: Hebb C. Bernardo Reporting Period: October 1, 2012 —December 31, 2012 Date This Form Was Prepared: December 6, 2012 Ecology Contacts: Regional Project Manager: Melisa Snoeberger Financial Manager: Jennifer Holderman Funding: Total Eligible Cost: $1,310,667 Total Ecology Award: $983,000 Total Expenditures to Date: $0 Task and Milestone Achievements (for current reporting period only) Task 1 —Project Administration/Management City staff completed the process of negotiating the grant agreement with Ecology and prepared agenda bill/issue paper for Council's authorization to allow the Mayor to sign the grant agreement. Agreement was signed by both parties. The consultant contract, scope of work,budget and schedule for project design has been prepared for City review and approval in January 2013. Task 2—(title) N/A Task 3— (title) N/A Task 4—(title) N/A 1 Tasks/Milestones not achieved and why None noted Potential Future Challenges to Performance (time delays, staff changes, etc.) None noted General Comments List the cumulative totals for all numerically measurable accomplishments for this calendar year (Example: amount of riparian area planted, length of fencing installed, technical assistance, conservation plans, etc)N/A Verification for State Revolving Fund Loan Recipients Only: ❑ By checking this box we verify that we are in compliance with all the requirements as outlined in our funding agreement(s)with the Department of Ecology. This includes but is not limited to: • The Davis-Bacon Act, 29 CFR (If applicable) • Washington State Prevailing Wage Rate, Chapter 39.12 RCW (Pertaining to all recipients) • The Disadvantaged Business Enterprise (DBE), 40 CFR, Part 33 (Pertaining to recipients that had a signed funding agreement(s) with Ecology on or after August 26, 2010) 2 TECHNICAL MEMORANDUM CH2MHILLo Design and Installation Considerations for Pervious Concrete Sidewalk PREPARED FOR: Hebe Bernardo, City of Renton PREPARED BY: CHZM HILL DATE: December 17, 2013 PROJECT NUMBER: 469718.03.35.20.00 Purpose This memo provides information for the City of Renton on the following topics related to the use of pervious concrete for pedestrian sidewalks: • Background and Benefits; • Design Considerations: Run-on from adjacent areas, potential for moss growth, and site suitability; • Sidewalk Material Alternatives and Construction/Installation Requirements; • Maintenance Requirements: General maintenance, Vacuum sweeper technology, winter maintenance considerations; Background Porous pavement is a green infrastructure technique that combines stormwater management with structural pavement to decrease runoff from impervious surfaces and improve the quality of water discharged to surface or ground water. Porous pavement systems consist of a pervious structural surface course underlain by an engineered gravel basecourse to provide detention and water quality improvements. Stormwater is then either infiltrated to the underlying natural (uncompacted) subgrade, or in cases where infiltration is inadequate or otherwise precluded by soil conditions or regulations, collected and discharged to a downstream system or surface water. Figure 1 provides a schematic illustration of porous pavement system designed for infiltration, while Figure 2 represents a more shallow section designed to reduce runoff but not necessarily to infiltrate runoff from adjacent surfaces. POROUS PAVEMENT 1 r A DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK g� Rain lands the d d d+ �--- parking lot surface d ; 1 .0----••-'— 1 Id ! d it d o d 1 d► t12 ...water flows through tiny spaces in the 4 pavement y d 1 }E� d d d — 3 n3 J14 _ x Figure 1: Pervious pavement system with infiltration to groundwater a t b pllm v%fq � wia'• 4. M Figure 2: Permeable pavement surface(From City of Seattle) Benefits Porous pavements provide multiple stormwater management benefits, most notably reduction in runoff volume and improved runoff water quality. Runoff Volume Reduction The City of Renton's proposed pervious sidewalk reduces overall runoff volume and the run-on from the sidewalk area contributed to adjacent bioretention. Water Quality Improvement Porous pavement systems offer water quality improvements regardless of whether they are designed for infiltration or discharge. As reported by Chopra (2010), "Research conducted on permeable pavement systems by Scholz and Grabowiecki (2007) shows that the structure itself can be used as an "effective in-situ aerobic bioreactor," 2 POROUSPAVEMENT_TM_V3.DOCX DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK and function as "pollution sinks" because of their inherent particle retention capacity during filtration due to its high porosity." The Texas Department of Transportation (2006) found that a porous pavement system without infiltration offered greater water quality improvements for TSS, total metals, and COD than the vegetated areas adjacent to the roadway. Removal rates for hydrocarbons from a non-infiltration porous pavement system have been demonstrated to be as high as 92 percent, nitrate removal at 69 percent. Metals removal rates from the same system were demonstrated at 35 percent for copper, 66 percent for zinc, 69 percent for cadmium, and 78 percent for lead (Pagotto et al., 2000). The Center for Watershed Protection (2000) compiled summary water quality performance data for infiltration BMPs including porous pavement systems, provided in Table 1. Table 1. Median Removal Efficiency for Infiltration Practices including Porous Pavement Systems" Pollutant Removal Efficiency (percent) Total Phosphorus 65 Soluble Phosphorus 85 Total Nitrogen 42 Copper 86 Zinc 66 TSS 89 a Adapted from"National Pollutant Removal Performance Database for Stormwater Treatment Practices,"Center for Watershed Protection Design Considerations The following list provides some key design considerations for porous pavement systems, based on CH2M HILL experience: • Infiltration testing is required (for designs that include infiltration instead of collection and discharge) • Provide free draining pavement section to expected frost depth or greater • Do not infiltrate on compacted soil • Level storage bed bottoms if infiltrating • Provide positive storm water overflow from infiltration bed • If possible, outlet pipes should connect to existing pipes immediately downstream of existing inlets Additional design limitations noted in the Western Washington Stormwater Management Manual (2012) include: POROUS PAVEMENT 3 COPYRIGHT 2014 BY CH2M HILL,INC.•COMPANY CONFIDENTIAL DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK • No run-on from pervious surfaces is preferred. If runoff comes from minor or incidental pervious areas, those areas must be fully stabilized. • Unless the pavement, base course, and subgrade have been designed to accept runoff from adjacent impervious surfaces, slope impervious runoff away from the permeable pavement to the maximum extent practicable. Sheet flow from up-gradient impervious areas is not recommended, but permissible if porous surface flow path > impervious surface flow path. Example design details for various situations are provided in Figures 3-6. Run-on from adjacent areas Designers must consider whether the porous pavement will receive run-on from adjacent areas in addition to run-off generated on-site.The overall thickness of the pavement structure will need to be increased if the porous pavement must mitigate for run-on; due to the increased volume of water, more storage is necessary. Infiltration rates must also be great enough to accommodate the run-on. Run-on can also contribute sediments and other debris to the porous pavement, which may impact maintenance requirements to sustain system performance. Potential for moss growth Moss growth can occur on both conventional impervious pavements and porous pavements in the Pacific Northwest. Pavement installations in shaded areas are more likely to be impacted by moss. Pressure washing, sweeping, and weed burning can be used to control moss growth (Gwilym 2011). The City of Bellevue (2009) notes on its Private Natural Drainage Practices Maintenance Inspection form that some moss is acceptable "as long as water is still able to infiltrate through pavement and that the moss is not a slipping hazard during wet weather." Additionally, while moss growth continues to occur in some places within the City of Seattle's High Point development, the homeowner's association which maintains the sidewalks has not noted any concerns (Gwilym 2013). Site Suitability Porous pavements are suitable for a range of uses and sites including sidewalks,walking paths, parking lots, playgrounds, plazas, tennis courts, low-traffic streets (i.e. residential) and other similar uses. Suitability of a site depends on the land use and other site characteristics such as slope and soil type. Hydrologic Soil Group (HSG) A&B soil types are preferred while HSG C&D may require underdrains. For pollution-generating surfaces, a three foot minimum separation is required between the bottom of the facility and the water table. Use in areas of potential groundwater contamination and unstable slope areas require special consideration, as described in the following paragraphs. Note also that Volume V: Runoff Treatment BMPS of the Stormwater Management Manual for Western Washington includes several criteria which render the use of porous pavements infeasible. This list is not repeated here in the interest of brevity, but should be consulted during project selection. Areas of Potential Groundwater Contamination Permeable pavements should not be used in heavy industrial developments, areas with chemical storage, fueling stations or areas with significant risk of spills that might contaminate groundwater. Permeable pavements should not be used for sites located over contaminated soils without placing an impermeable liner between the pavement structure and soils. 4 POROUSPAVEMENT_TM_V3.DOCX DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK Unstable slope areas Porous pavement should not be used in slip prone areas where concentrated infiltration may exacerbate slope instability Steep slopes-areas with slopes steeper than 10 percent present design challenges that are difficult to overcome Sediment sources-sites with sources of sediment (from vehicles, bare soils, spoil piles, sand storage, etc.) should be separated from permeable pavements with filter strips or other sediment removal practices. Areas with Leaf and Needle Litter, Excessive Sediment Deposition, or Sanding Areas with leaf and needle litter, excessive sediment deposition due to run-on or other factors, or subjected to sanding for traction control are likely to clog more quickly than installations in areas without those considerations. Sites with sources of sediment (from vehicles, bare soils, spoil piles, sand storage, etc.) should be separated from permeable pavements with filter strips or other sediment removal practices. Anecdotal evidence has been reported that pine needles have been difficult to remove from areas with larger aggregate in the mix design (Gwilym 2011). Example Design Details —EXTEND Gft1TEK'S,E�t: TH.t:IG'7C;,Mi 2"x s cauArsacx$TA1rK E53 5T't= E+cl!r40 Yrr ANCHOR STAKE LOURS 32' ONCE NTEA-RMSCAV4 wxGFCT #-E Al'TER BITE STANK_A.f Ir% NON-WOVEN GEOTEITTILE(BOTTOM Jf'f NYS'f GtnPETIs7t#iE."rfiC.£ AND SIDES.FOLD R EDGE" DURING CONSTRUCTION TO PREVENT POROUS ASPHALT SEDIMENT FROM ENTERING BED) I ( SURFACE AND BASE 30 MIL HDPE 9,6'PO��GtFS ASV--At'* GEOMEMBRANE F.i ✓ J AISIMACE GC4IRW AND CLEAN WASHED. WATERSTOP i° TA&-VtT'REArU, UNIFORMLY GRADED ,j £RASE COARSE AGGREGATE � (MIN.24'NYSDOT{rS1) STANDARD BASE PAVING -7 C"CKZR e ESL 33'gg,R _� } 40%tYJ.t AND S2A 40 sr" 't= 5TONE a �w ;OP'1QkAi} a eo e i 24'MIN 2 '+KITES:: •.,.,--CLEAN AA' i). ��.. 1 E.M(':'ENRY GFOTBXT4.E CVERt t7NSFf.:RALY QkAoto COAOUr t'X WRUCT"*O PRiVL.Y" IVOIA •e.ALt4O£Tfi2t4M',#' C CATE Sk,:TAT"OF 3F9 �Y UNCOMPACTED SOIL COMPACTED SUBSTRATE }„PLACE GEOTE.xTIt.E ALO BOTTOM ANpVYASKID STO6JE3 St;FS OF ACCREGAT€,fox TRATfON R:£a'S NOTE:INSTALL 30 MIL HOPE GEOMEMBRANE A� Pf4 L&OFIRRRSTCavf E BETWEEN INFILTRATION AREAS AND ADJACENT 3 0,NOT CCWACT.OR A OW V� PAVEMENT SUBBASE;EXTEND MIN 24'ALONG ESks`N>MtY4.'t?T,WtVtti.$C.BED A3"gA SIDE SLOPE OF BED AND 6'.LONG VERTICAL EDGE (TOTAL6Et SPCQ1FCAT"S. OVERLAP THETCEOIEMBRANEOF RATETHE SEAMS. Figure 3: Typical porous pavement I riverstone edge treatment Figure 4: Waterstop between porous pavement infiltration bed and adjacent pavement subbase 12'Riverstone Edge only where stormwater run-on Porous Pavement is expected. .-.-„�..... 12'Riverstone Edge (match concrete color) 1 '"'.^.' sloe" 6'Subbase (NYS DOT a3 Stone) --""i 24t' , Unwmpacted subgrade beneath ### ' porous pavement � v.3 Infiltration Trench with NOTES:Line with geotextile: NYS DOT#3 stone Longitudinal trench slope to match surface slope Figure 5: Full porous sidewalk with subsurface infiltration trench POROUS PAVEMENT 5 COPYRIGHT 2014 BY CH2M HILL,INC.•COMPANY CONFIDENTIAL DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK 12'Riverstone Edge Porous Pavement only where stormwater (match concrete color) - run=bn is expected 12°Riverstone Edge __ `. - i r 2-Ct --uncompacted subgrade beneath "� - — -- porous pavement Infiltration Trench with NOTES'line with geotextile; NYS DOT 93 stone longitudinal trench slope to match surface slope Figure 6: Partial porous sidewalk with subsurface infiltration trench Material Alternatives There are a variety of permeable pavement surfaces available in the commercial market-place, including pervious concrete, porous asphalt, permeable interlocking concrete pavers, clay pavers, concrete grid pavers, and plastic grid pavers.These materials can be broadly categorized into those where water seeps directly through the material pore structure (pervious concrete, porous asphalt),and those where water seeps through pervious gaps between non-pervious blocks (interlocking concrete pavers, clay pavers, etc.). Pervious Portland Cement Concrete As described in the Stormwater Management Manual for Western Washington (2012), "pervious Portland cement concrete is a rigid pavement similar to conventional concrete that uses a cementitious material to bind aggregate together. However, the fine aggregate (sand) component is reduced or eliminated in the gradation and, as a result,voids form between the aggregate in the pavement surface and allow water to infiltrate." Similar to porous asphalt, pervious concrete allows water to infiltrate directly through the pore structure to the base course below. Fine grained PCC Pervious Portland cement concrete can be batched with more sand, creating smaller voids and reducing some of the visual difference between impervious and pervious concrete. Increased sand content and finer voids may, however, increase sediment retention and moss growth near the surface of the pavement, requiring increased maintenance. Construction/Installation Requirements In addition to common issues associated with construction of traditional impervious pavement, considerations required during installation of pervious concrete include: • Erosion control more critical • Protection of native soil and base course required to maintain infiltration capacity • More precise batching and more skilled installation required • Must verify contractor qualifications and training • More testing and inspection required during construction • Special techniques required for placement, finishing, and curing Figure 7 shows a pervious concrete installation that appears to demonstrate some of the potential pitfalls of pervious concrete design and construction. In addition to receiving run-on and nutrients from the adjacent grass area,the concrete mix appears to have excessive fines or to have been incorrectly trowelled during 6 POROUSPAVEMENT_TM_V3.DOCX DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK construction. Nutrients, poor drainage, moisture, and surface texture are apparently accelerating moss growth. 51 `a "+ 6 1 • M, f +.� -5k4 3"Y ♦(ft fir'x•- } °_. •° I � 4 f !Y 'gam Figure T Example Demonstrating Challenges of Pervious Concrete Installation Maintenance Requirements In addition to the following descriptions of maintenance activities, utility cuts should be backfilled with the same aggregate base used under the permeable paving to allow continued conveyance of stormwater through the base, and to prevent migration of fines from the standard base aggregate to the more open graded permeable base material. General Maintenance The primary goal of porous pavement maintenance is to prevent the pavement surface and/or underlying infiltration bed from being clogged with fine sediments. Several studies have shown that the various material alternatives will plug, to varying degrees, with silt, fine clay, cement derivatives, and decomposed plant material. In order to maintain design percolation rates, the pavement surface should be vacuumed, generally at least twice a year, with a commercial cleaning unit. More frequent cleaning may be desirable for aesthetic purposes such as the removal of cigarette butts and other micro-garbage or for removal of heavy leaf or tree needle littler. Planted areas adjacent to porous pavement should be well maintained to prevent soil washout onto the pavement. If any washout does occur, it should be cleaned off the pavement immediately to prevent further clogging of the pores. Furthermore, if any bare spots or eroded areas are observed within the planted areas, they should be replanted and/or stabilized as soon as possible. Planted areas should be inspected on a semi-annual basis. Fast-growing groundcover plants such as fragaria species (strawberries) may spread too aggressively and take root in the porous pavement, reducing performance of the pavement. Superficial dirt does not necessarily clog the pavement voids. However, dirt that is ground in repeatedly by tires can lead to clogging. Therefore, trucks or other heavy vehicles should be prevented from tracking or spilling dirt onto the pavement. Furthermore, all construction or hazardous materials carriers should be prohibited from entering the porous pavement installation. Descriptive signage is recommended to maintain institutional memory of porous pavement. POROUS PAVEMENT 7 COPYRIGHT 2014 BY CH2M HILL,INC.•COMPANY CONFIDENTIAL DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK Vacuuming To keep the systems performing at design rates and to prolong their lifespans, porous pavement surfaces should typically be vacuumed with a commercial-grade cleaning unit approximately twice per year. In areas that receive unusually high amounts of sediment or debris,vacuuming should be done more frequently; in pristine areas,vacuuming may be reduced. For significantly clogged pavement, a low-pressure wash with non-toxic detergent cleaning solution may increase effectiveness once allowed to soak-in, and immediately followed by vacuuming. There are two types of commercial-grade equipment readily available for this application: • Vacuum sweepers • Regenerative air sweepers Note: simple broom sweepers are not recommended for porous pavement maintenance. Sweeper Technologies Vacuum Sweepers Vacuum-type street cleaning equipment is the most effective at loosening and removing sediment from the openings in porous pavement. Fine particles are vacuumed out of the pavement matrix and are collected in the sweeper hopper. It is important to note whether a given sweeper model is a pure vacuum sweeper as often the word "vacuum" is misused by industry salesman to describe regenerative air sweepers (described below). Regenerative Air Sweepers Regenerative air sweeper units contain a blower system that generates a high velocity air column, forcing it against the pavement at an angle, and creating a "peeling" or"knifing" effect.The high volume air blast loosens the debris from the pavement surface,then transports it across the width of the sweeping head and lifts it into the containment hopper via a suction tube. Regenerative air sweepers are generally not recommended for porous pavements as they tend to move the sediment rather than remove it. Some research has shown that biannual maintenance with a regenerative air sweeper will keep porous pavement clean; however, a pure vacuum sweeper will perform better for the combined applications of routine (biannual) maintenance and restoration of partially clogged porous pavement.This research has been gathered by multiple sources including the Permeable Interlocking Concrete Paver(PICP) Institute, University of Central Florida, and the vacuum vendor Elgin. 8 POROUSPAVEMENT_TM_V3.DOCX DESIGN AND INSTALLATION CONSIDERATIONS FOR PERVIOUS CONCRETE SIDEWALK • Cleaning is recommended if the measured infiltration rate falls below 10 in/hr. • For badly clogged installations, wet the surface and vacuume aggregate to a depth that removes all visible fine sediment and replace with clean aggregate. • Pavers can be removed individually and replaced when utility work is complete. • Replace broken pavers as necessary to prevent structural instability in the surface. Winter Maintenance Considerations Multiple sources report anecdotal evidence that less salting is required for deicing pervious sidewalks/ parking lots compared to traditional impervious surfaces. Vacuum manufacturer Elgin recommends that if salt has to be applied, a filtered liquid should be used instead of common de-icing salt which can have up to 10 percent dirt content. Elgin also recommends that snow not be piled onto porous pavement surfaces, as the piles contain a relatively large amount of dirt and grit that could contribute to clogging of the porous surface.This recommendation is particularly pertinent in the Pacific Northwest, where gravel and sand are used for traction control rather than salt. References Chopra, M., Stuart, E., and Wanielista, M., 2010. "Pervious Pavement Systems in Florida—Research Results," Stormwater Management Academy, University of Central Florida, Orlando, Florida, USA, as published in ASCE Low Impact Development 2010: Redefining Water in the City. Gwilym, K., 2011. "Operations and Maintenance for Porous Pavements." WSU and Puget Sound Partnership Permeable Pavement Workshop. Gwilym, K., 2013. Personal Communication. Pagotto et al, 2000. "Comparison Of The Hydraulic Behaviour And The Quality Of Highway Runoff Water According To The Type Of Pavement," Wat. Res. Vol. 34, No. 18, pp. 4446±4454, 2000 TxDOT Study: Barrett, M., 2006. "Stormwater Quality Benefits of a Permeable Friction Course," Proceedings of the World Environmental and Water Resources Congress 2006 Omaha, Nebraska, USA. Washington State Department of Ecology Water Quality Program, 2012. "Stormwater Management Manual for Western Washington.Volume 5: Runoff Treatment BMPs." Publication No. 12-10-030 (A revision of Publication No. 05-10-033) POROUS PAVEMENT 9 COPYRIGHT 2014 BY CH2M HILL,INC.•COMPANY CONFIDENTIAL