CITY OF PUYALLUP TOSCANOS SINKHOLE EVALUATION

Transcription

1 CITY OF PUYALLUP PIERCE COUNTY WASHINGTON TOSCANOS SINKHOLE EVALUATION G&O #15470 OCTOBER 2015

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5 TABLE OF CONTENTS BACKGROUND...1 EXISTING SYSTEM...1 Stormwater Conveyance System...1 Video Inspection...2 Geotechnical Investigation...2 Hydrologic and Hydraulic Model...2 ALTERNATIVES...3 Do Nothing...3 Repair the Detention System...3 Replace the Detention System...4 Abandon the Detention System...4 RECOMMENDATION...4 LIST OF TABLES No. Table Page 1 Hydrologic Model Summary...3 LIST OF FIGURES No. Figure Follows Page 1 Vicinity Map Drainage Area Survey Base Map Abandon Existing Detention System...4 APPENDICES Appendix A Geotechnical Investigation Appendix B Model Results Appendix C Cost Estimates Appendix D Existing System Hydraulic Profile Appendix E New System Hydraulic Profile i

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7 Gray & Osborne, Inc., Consulting Engineers BACKGROUND In 2012, multiple surface settlements (sinkholes) appeared in the parking lot of the Toscanos Italian Grill restaurant in the vicinity of a stormwater detention system. The detention system is adjacent to Toscanos and located beneath the parking lot of a small commercial development along 29 th Street NE. This stormwater detention system in the vicinity of the intersection of East Main Avenue and 5 th Avenue NE in the City of Puyallup currently fails to function as designed. The City wishes to evaluate the feasibility of removing or rehabilitating the existing stormwater detention system to alleviate the drainage issues currently on site. EXISTING SYSTEM The existing system was installed in 1979 as part of the development of the nearby Linden Estates. Another portion of the system was installed as part of the Riverside Commercial Development in The detention system is comprised of 36-inch and 54-inch CMP pipes and is approximately 440 feet long. It extends within a 20-foot easement located in the parking lots of two retail/services buildings and Toscanos Italian Grill. The sinkholes seem to be on the downstream (northeast) end at the Toscanos Italian Grill parking lot at approximately th Street NE. Lots 4 and 5 (including the Toscanos restaurant) were developed in 2003, almost 25 years aer installation of the detention system. The detention system discharges flows to the northeast to an outfall on the Puyallup River. Figure 1 indicates the location of the project site. STORMWATER CONVEYANCE SYSTEM Figure 2 shows the drainage basins that are tributary to the detention system and to the 24-inch concrete outfall. An area of approximately 38.7 acres is tributary to the 24-inch concrete outfall pipe. The detention system collects flows from approximately 24.5 acres of this area. The entire subbasin is fully developed and contains commercial retail buildings, apartments, and condominiums. Land cover in the subbasin is approximately 90 percent impervious. The City identifies the larger drainage basin as the Puyallup River South basin. The City has a stormwater base map in both AutoCAD and GIS, which was used to explore the existing system. The City s GIS base map includes infrastructure quality data from 2009, 2011, or 2013, when the various sections of the stormwater system in the project area were surveyed. All of the pipes, manholes, and inlets in the project s subbasin are labeled as being in good quality. The stormwater conveyance elements in the subbasin are partially commercially owned and partially publicly owned. Gray & Osborne conducted survey as part of this study in order to determine exact pipe sizes, slopes, materials, and locations, as well as to investigate the condition of the existing stormwater infrastructure. The survey base map may be seen on Figure 3. City of Puyallup 1 Toscanos Sinkhole Evaluation October 2015

8 Gray & Osborne, Inc., Consulting Engineers VIDEO INSPECTION The City of Puyallup maintenance staff completed a television inspection of the detention system in the summer of 2012 to investigate the potential pipe leakage. The investigation found many areas of groundwater infiltration into the pipe and found a large void about 19 feet to the west of Catch Basin D in one of the 48-inch sections of the detention system. The pipe to the west of Catch Basin D appears to be the primary source of the sinkhole problem. The other pipes in the system were found to have smaller amounts of infiltration that included material migration. These areas of infiltration are identified on Figure 3. In 2012, City crews filled the sinkhole using controlled density fill (CDF) within the parking lot. No video inspection was provided post repair. It is recommended that a re-inspection of the detention system be conducted to see if the infiltration continues to include material migration, as was apparent in The detention system should be thoroughly cleaned prior to the video inspection. GEOTECHNICAL INVESTIGATION A geotechnical investigation was conducted as part of this feasibility study by PanGEO, Inc. in June 2015 and is included as Appendix A. The investigation found soils on site to be comprised mostly of alluvium. Alluvium consists of dense sand, silt, and clay. The geotechnical investigation analyzed the subsurface condition surrounding the sinkholes with respect to groundwater levels and soil types. A cone penetration test (CPT) was conducted as part of the geotechnical investigation. That test found no evidence of voids or zones of disturbance within the parking lot. HYDROLOGIC AND HYDRAULIC MODEL A stormwater hydrologic model using the Santa Barbara Unit Hydrograph (SBUH) was used with an XP-SWMM hydraulic model methodology to determine peak flow and system capacity. For comparison, peak flow rates were also determined using the Western Washington Hydrology Model (WWHM). A summary of the results of the two models is shown in Table 1. 2 City of Puyallup October 2015 Toscanos Sinkhole Evaluation

9 Approximate Tributary Basin Stormwater Outfall Project Site LEGEND: City Limits Storm Pipes 10' Topo streams ,000 CITY OF PUYALLUP ± TOSCANOS SINKHOLE FEASIBILITY STUDY FIGURE 1 - VICINITY MAP 2,000 Feet M:\PUYALLUP\15470 Toscanos Sinkhole Evaluation\GIS\Figure1.mxd

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11 LEGEND: City Limits Storm Pipes Manholes Inlets Parcels Storm Basins 10' Topo streams CITY OF PUYALLUP ± TOSCANOS SINKHOLE FEASIBILITY STUDY FIGURE 2 - DRAINGE AREA 500 Feet M:\PUYALLUP\15470 Toscanos Sinkhole Evaluation\GIS\toscano basin.mxd

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13 PLAN Areas of infiltration Identified on video inspection ' 0 20' 40' SCALE: 1"=40' CITY OF PUYALLUP TOSCONOS SINKHOLE EVALUATION FIGURE 3 SITE PLAN AND PROFILE PROFILE

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15 Gray & Osborne, Inc., Consulting Engineers TABLE 1 Hydrologic Model Summary SBUH WWHM Peak Flow Peak Peak Flow Peak Storm Event Frequency Design Storm at Detention System (cfs) Flow at Outfall (cfs) at Detention System (cfs) Flow at Outfall (cfs) 25-Year 3.5", Type 1A Year 4.1", Type 1A The hydraulic model assumed no backwater condition at the outfall to the Puyallup River. The maximum hydraulic grade, as well as applicable model results, may be seen for the 25- and 100-year storm events in Appendix B. Although the downstream stormwater conveyance does not have an open-channel flow capacity (based on Mannings equation) for the 25- or 100-year storm events, the model indicates that the hydraulic grade line (HGL) for these events are below the ground surface. The hydraulic model output shows that the maximum water elevation downstream of the detention system during the 25- and 100-year storm events is 6.3 and 4.4 feet below the ground surface, respectively. ALTERNATIVES The following alternatives were considered for the detention system and discussed below: Do Nothing Repair the Detention System Replace the Detention System Remove the Detention System Detailed cost estimates for each of the alternatives may be seen in Appendix C. DO NOTHING Because the surface settlements caused by the failing detention system require frequent ongoing maintenance to correct, doing nothing to this system is likely to lead to additional failures and is not considered to be a feasible alternative. REPAIR THE DETENTION SYSTEM The detention system may be lined in situ to eliminate the groundwater infiltration and material migration. Cured-in-place pipe (CIPP) lining is feasible for pipes as large as 96-inch diameter. A video inspection of the pipe, following cleaning, would confirm that City of Puyallup 3 Toscanos Sinkhole Evaluation October 2015

16 Gray & Osborne, Inc., Consulting Engineers the pipe is in adequate condition to be repaired by CIPP lining. Following CIPP lining, pressure grouting should be completed in the locations of active infiltration. The estimated cost to repair the detention system is $440,000. REPLACE THE DETENTION SYSTEM The detention system could be replaced with a new stormwater pipe. If the existing detention system was excavated and the top half of the pipe removed, a new pipe could be placed within the bottom half of the pipe at a slightly higher invert elevation. The new pipe could be backfilled in the same location as the current detention pipe. The hydraulic profile of the system using 24-inch diameter or 30-inch diameter pipes to replace the existing detention system is included in Appendix D. Following installation of the new pipe, pressure grouting should be completed in the locations of active infiltration. The estimated cost to replace the detention system is $344,000. ABANDON THE DETENTION SYSTEM The detention system could be abandoned if a new stormwater conveyance system was installed in 29 th Street NE and 5 th Avenue NE. The stormwater conveyance system would include 18- and 30-inch diameter pipe. The approximate alignment of the new conveyance system is shown on Figure 4. The hydraulic profile of the new system is included in Appendix E. The estimated cost to abandon the detention system is $517,000. RECOMMENDATION In the short term, it is recommended that another video inspection of the detention system be conducted, following a thorough cleaning of the system, to indicate if material is being actively transported through the system. This video inspection will be used to confirm the feasibility of the recommended long-term alternative of lining the detention system. 4 City of Puyallup October 2015 Toscanos Sinkhole Evaluation

17 4TH AVE NE 25' 12.5' 0 25' 50' SCALE: 1"=50' JOHN L SCOTT TOSCONOS CAFE CITY OF PUYALLUP TOSCONOS SINKHOLE EVALUATION FIGURE 4 ABANDON EXISTING DETENTION SYSTEM

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19 APPENDIX A GEOTECHNICAL INVESTIGATION

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21 June 29, 2015 File No. P-3681 Geotechnical & Earthquake Engineering Consultants Mr. Barry Baker, P.E. Gray & Osborne, Inc th St. NE, Suite B210 Arlington, WA Subject: Summary of Subsurface Exploration Settlement Evaluation th Street NE, Puyallup, WA (Toscanos Italian Grill) Dear Mr. Baker, As requested, we completed a subsurface surface exploration program to assist the City with the settlement evaluation at the subject site. The approximate location of the site is shown in Figure 1. We understand that a city-owned storm pipe located in the parking lot in front of the subject building failed several years ago, and resulted in subsidence of ground surface. The City subsequently replaced a section of the storm pipe, and backfilled the excavation to repair the subsidence. We understand the City intends to evaluate if potential ground disturbance (i.e., if piping of soils) are present near the existing storm facility that may adversely impact the area in the future. SUBSURFACE EXPLORATION To evaluate if voids or disturbed zones may be present below the parking lot, Cone Penetration Test (CPT) was conducted at five locations on June 13, The approximate CPT locations (CPT-1 through CPT-5) are indicated on the attached Figures 2 and 3. The test was completed by In Situ Engineering of Snohomish, Washington, under a subcontract to PanGEO. In Situ Engineering uses an instrumented cone approximately 1½ inches in diameter, which is pushed against a truck at a slow steady rate into the soil to measure tip resistance (Qc), side friction (Fs), pore water pressure (u), and inclination (i). The readings on the soil are usually taken at about Eastlake Avenue East, Suite B Seattle, WA Tel: (206) Fax: (206)

22 Geotechnical Engineering Study Settlement Evaluation: th Street NE, Puyallup, WA June 29, 2015 inch vertical intervals, and provide a nearly continuous readout of soil stratigraphy, strength and other parameters. The results from the CPT are plotted on the CPT logs included in Appendix A. GEOLOGY According to the geologic map of the area compiled by Troost (in review), the surficial geologic unit at the project site is alluvium (map unit Qal). Alluvium typically consists of a sequence of loose to dense sand and silty sand, and so to stiff silt and clay. SUMMARY INTERPRETATION OF CPT DATA In general, the CPT data from the five test locations are quite consistent, and consisted of approximately 1½ to 3 feet thick crust of well-compacted granular soils. This upper crust is likely structural fill that was placed for the construction of the parking lot. Below the crust, an interbedded sequence of loose to medium dense sand to medium stiff to stiff silt was encountered in the CPT. We interpret this layer as the native alluvium. The measured CPT tip resistance within this layer is consistent with undisturbed alluvium typically found in this region. In summary, based on our evaluation of the CPT data, it is our opinion that no evidence of voids or zones of disturbance were encountered at the CPT locations. Please call should you have any questions regarding this proposal. Sincerely, Siew L. Tan, P.E. Principal Geotechnical Engineer Enclosures: Figure 1 Figure 2 Figure 3 Appendix A Vicinity Map Site and Exploration Plan Photos of Site Conditions with CPT Locations Summary CPT Logs (CPT-1 through CPT-5) Toscano Settlement Evaluation Page 2 of 2 PanGEO, Inc.

23 Fig1_vicinity.ppt 6/29/2015(1:12 PM) JC Crop map to 6.85 x 7 SITE LOCATION Image Credit: Google Maps N Not to Scale Settlement Evaluation th Street NE Puyallup, Washington Project No. VICINITY MAP Figure No

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25 29th St NE CPT-1 CPT-2 CPT-5 CPT-3 CPT-4 file.grf w/ file.dat 6/29/15 (8:32 ) TEA2 LEGEND: CPT Location Settlement Evaluation th Street NE Puyallup, WA SITE AND EXPLORATION PLAN Project No. Figure No

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27 CPT-4 CPT-3 CPT-1 CPT-5 CPT-2 file.grf w/ file.dat 6/29/15 (8:31 ) TEA2 Settlement Evaluation th Street NE Puyallup, WA Project No. PHOTOS OF SITE CONDITIONS WITH CPT LOCATIONS Figure No

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29 Geotechnical Engineering Study Settlement Evaluation: th Street NE, Puyallup, WA June 29, 2015 Appendix A Summary CPT Logs

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31 PanGeo Toscanos CPT-01 Operator: Brown/Mayfield Sounding: CPT-01 Cone Used: DDG1327 CPT Date/Time: 6/13/2015 7:16:57 AM Location: Toscanos Puyallup Job Number: Tip Resistance Friction Ratio Pore Pressure Soil Behavior Type* SPT N* 0 0 Qc TSF 160 Fs/Qc (%) 0 8 Pw PSI Zone: UBC % Hammer Depth () Maximum Depth = feet Depth Increment = feet 1 sensitive fine grained 2 organic material 3 clay InSitu Engineering 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *Soil behavior type and SPT based on data from UBC-1983

32 PanGeo Toscanos CPT-02 Operator: Brown/Mayfield Sounding: CPT-02 Cone Used: DDG1327 CPT Date/Time: 6/13/2015 7:40:01 AM Location: Toscanos Puyallup Job Number: Tip Resistance Friction Ratio Pore Pressure Soil Behavior Type* SPT N* 0 0 Qc TSF 160 Fs/Qc (%) 0 8 Pw PSI Zone: UBC % Hammer Depth () Maximum Depth = feet Depth Increment = feet 1 sensitive fine grained 2 organic material 3 clay InSitu Engineering 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *Soil behavior type and SPT based on data from UBC-1983

33 PanGeo Toscanos CPT-3 Operator: Brown/Mayfield Sounding: CPT-03 Cone Used: DDG1327 CPT Date/Time: 6/13/2015 8:15:45 AM Location: Toscanos Puyallup Job Number: Tip Resistance Friction Ratio Pore Pressure Soil Behavior Type* SPT N* 0 0 Qc TSF 160 Fs/Qc (%) 0 8 Pw PSI Zone: UBC % Hammer Depth () Maximum Depth = feet Depth Increment = feet 1 sensitive fine grained 2 organic material 3 clay InSitu Engineering 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *Soil behavior type and SPT based on data from UBC-1983

34 PanGeo Toscanos CPT-04 Operator: Brown/Mayfield Sounding: CPT-04 Cone Used: DDG1327 CPT Date/Time: 6/13/2015 8:33:49 AM Location: Toscanos Puyallup Job Number: Tip Resistance Friction Ratio Pore Pressure Soil Behavior Type* SPT N* 0 0 Qc TSF 160 Fs/Qc (%) 0 8 Pw PSI Zone: UBC % Hammer Depth () Maximum Depth = feet Depth Increment = feet 1 sensitive fine grained 2 organic material 3 clay InSitu Engineering 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *Soil behavior type and SPT based on data from UBC-1983

35 PanGeo Toscanos CPT-05 Operator: Brown/Mayfield Sounding: CPT-05 Cone Used: DDG1327 CPT Date/Time: 6/13/2015 8:55:21 AM Location: Toscanos Puyallup Job Number: Tip Resistance Friction Ratio Pore Pressure Soil Behavior Type* SPT N* 0 0 Qc TSF 160 Fs/Qc (%) 0 8 Pw PSI Zone: UBC % Hammer Depth () Maximum Depth = feet Depth Increment = feet 1 sensitive fine grained 2 organic material 3 clay InSitu Engineering 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *Soil behavior type and SPT based on data from UBC-1983

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37 APPENDIX B MODEL RESULTS

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39 Untitled Day [0] Time 00:01:00 Step 1 Conduit from D to D Conduit 406 from D to D Conduit 404 from D to D

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41 Pipes Name Upstream Node Name Downstream Node Name Diameter (Height) Length Downstream Invert Elevation Upstream Invert Elevation Maximum Water Elevation (US) Design Full Flow cfs Max Flow cfs Pipe Surcharge at U/S m Duration of Surcharged Flow min 404 D D D D D D D D D D D D D D D D D D D D D D D D D Max Depth 09/11/15 14:47:04 1/1

42 Manholes Name Ground Invert Max Water Volume of Duration of EGL Surcharge Subcatchme Rainfall Max Flow Freeboard nt Elevation (Spill Elevation Elevation Ponded Flow Surcharge Reference cfs Elevation at Max Crest) Stored (min) HGL ^ sec D D D Yr SCS D D Yr SCS D Yr SCS D D Yr SCS D D D D D Yr SCS /11/15 14:45:05 1/1

43 Untitled Day [0] Time 00:01:00 Step 1 Conduit from D to D Conduit 406 from D to D Conduit 404 from D to D

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45 Pipes Name Upstream Node Name Downstream Node Name Diameter (Height) Length Downstream Invert Elevation Upstream Invert Elevation Maximum Water Elevation (US) Design Full Flow cfs Max Flow cfs Pipe Surcharge at U/S m Duration of Surcharged Flow min D D D D D D D D D D D D D D D D D D D D D D D D D Max Depth 09/11/15 14:55:13 1/1

46 Manholes Name Ground Invert Max Water Volume of Duration of EGL Surcharge at Subcatchme Rainfall Max Flow Freeboard nt Elevation Elevation Elevation Ponded Surcharge Reference cfs Elevation Max HGL (Spill Crest) Flow Stored (min) ^ sec D D D Yr S D D Yr S D Yr S D D Yr S D D D D Yr S D /11/15 14:54:00 1/1

47 APPENDIX C COST ESTIMATES

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49 City of Puyallup Preliminary Construction Cost Estimate Toscanos Sinkhole Evaluation Repair Existing Detention System August 2015 Item Quantity Unit Cost Total 1 Mobilization/Demobilization 1 LS $ 25,000 $ 25,000 2 Minor Changes 1 LS $ 5,000 $ 5,000 3 Surveying, Staking and Record Dwgs 1 LS $ 2,000 $ 2,000 4 Traffic Control 1 LS $ 2,000 $ 2,000 5 Environmental Controls 1 LS $ 3,000 $ 3,000 6 Trench Excavation Safety Systems 0 LS $ 1,000 $ - 7 Dewatering 1 LS $ 1,000 $ 1,000 8 Removal of Structure and Obstruction 1 LS $ 1,000 $ 1,000 9 Locate Existing Utilities 1 LS $ 1,000 $ 1, Cast In Place Pipe 430 LF $ 350 $ 150, Pressure Grouting 6 EA $ 3,000 $ 18, Cement Concrete Sidewalk 0 SY $ 50 $ - 13 Bankrun Gravel for Trench Backfill 0 TN $ 25 $ - 14 Crushed Surfacing Base Course 0 TN $ 25 $ - 15 Hot Mix Asphalt 4 TN $ 100 $ Landscaping Restoration 0 LS $ 1,000 $ - Subtotal $ 208,900 Contingency (25%) $ 52,225 Subtotal $ 261,125 Sales Tax (9.4%) $ 24,546 Total $ 285,671 Total Construction Cost (Rounded) $ 286,000 All Overhead (25%) $ 72,000 Total Project Cost (Rounded) $ 358,000 M:\PUYALLUP\15470 Toscanos Sinkhole Evaluation\Costs Toscanos.xlsx\Repair 8/28/2015

50 City of Puyallup Preliminary Construction Cost Estimate Toscanos Sinkhole Evaluation Replace Existing Detention System August 2015 Item Quantity Unit Cost Total 1 Mobilization/Demobilization 1 LS $ 25,000 $ 25,000 2 Minor Changes 1 LS $ 5,000 $ 5,000 3 Surveying, Staking and Record Dwgs 1 LS $ 2,000 $ 2,000 4 Traffic Control 1 LS $ 2,000 $ 2,000 5 Environmental Controls 1 LS $ 3,000 $ 3,000 6 Trench Excavation Safety Systems 1 LS $ 1,000 $ 1,000 7 Dewatering 1 LS $ 1,000 $ 1,000 8 Removal of Structure and Obstruction 1 LS $ 20,000 $ 20,000 9 Locate Existing Utilities 1 LS $ 2,000 $ 2, " CPEP (Including bedding, backfill) 430 LF $ 80 $ 34, Pressure Grouting 6 EA $ 5,000 $ 30, Cement Concrete Sidewalk 310 SY $ 50 $ 15, Bankrun Gravel for Trench Backfill 900 TN $ 25 $ 22, Crushed Surfacing Base Course 180 TN $ 25 $ 4, Hot Mix Asphalt 320 TN $ 100 $ 32, Landscaping Restoration 1 LS $ 1,000 $ 1,000 Subtotal $ 200,900 Contingency (25%) $ 50,225 Subtotal $ 251,125 Sales Tax (9.4%) $ 23,606 Total $ 274,731 Total Construction Cost (Rounded) $ 275,000 All Overhead (25%) $ 69,000 Total Project Cost (Rounded) $ 344,000 M:\PUYALLUP\15470 Toscanos Sinkhole Evaluation\Costs Toscanos.xlsx\Replace 8/24/2015

51 City of Puyallup Preliminary Construction Cost Estimate Toscanos Sinkhole Evaluation Abandon Existing Detention System August 2015 Item Quantity Unit Cost Total 1 Mobilization/Demobilization 1 LS $ 35,000 $ 35,000 2 Minor Changes 1 LS $ 5,000 $ 5,000 3 Surveying, Staking and Record Dwgs 1 LS $ 2,000 $ 2,000 4 Traffic Control 1 LS $ 8,000 $ 8,000 5 Environmental Controls 1 LS $ 4,000 $ 4,000 6 Trench Excavation Safety Systems 1 LS $ 4,000 $ 4,000 7 Dewatering 1 LS $ 2,000 $ 2,000 8 Removal of Structure and Obstruction 1 LS $ 5,000 $ 5,000 9 Locate Existing Utilities 1 LS $ 5,000 $ 5, " CPEP (Including bedding, backfill) 240 LF $ 100 $ 24, " CPEP (Including bedding, backfill) 380 LF $ 70 $ 26, " CPEP (Including bedding, backfill) 120 LF $ 60 $ 7, Catch Basin, Type 2, 48" (Basic to 8') 2 EA $ 2,500 $ 5, Catch Basin, Type 2, 54" (Basic to 8') 4 EA $ 3,000 $ 12, Catch Basin, Type 2, 54" (Over 8') 27 VF $ 200 $ 5, Connection to Existing System 2 EA $ 2,000 $ 4, Foundation Gravel 10 TN $ 20 $ CDF to Abandon Existing Detention System 160 CY $ 150 $ 24, Cement Concrete Sidewalk 360 SY $ 50 $ 18, Bankrun Gravel for Trench Backfill 1,500 TN $ 25 $ 37, Crushed Surfacing Base Course 300 TN $ 25 $ 7, Hot Mix Asphalt 550 TN $ 100 $ 55, Landscaping Restoration 1 LS $ 5,000 $ 5,000 Subtotal $ 301,400 Contingency (25%) $ 75,350 Subtotal $ 376,750 Sales Tax (9.4%) $ 35,415 Total $ 412,165 Total Construction Cost (Rounded) $ 413,000 All Overhead (25%) $ 104,000 Total Project Cost (Rounded) $ 517,000 M:\PUYALLUP\15470 Toscanos Sinkhole Evaluation\Costs Toscanos.xlsx\Abandon 8/24/2015

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53 APPENDIX D EXISTING SYSTEM HYDRAULIC PROFILE

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55 Conduit from D to D Untitled Day [0] Time 00:01:00 Step 1 Conduit 406 from D to D Conduit 404 from D to D D D D D D D D D D D D D D

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57 Pipes Name Upstream Node Name Downstream Node Name Diameter (Height) Length Downstream Invert Elevation Upstream Invert Elevation Maximum Water Elevation (US) Design Full Flow cfs Max Flow cfs Pipe Surcharge at U/S m Duration of Surcharged Flow min 8576 D D D D D D D D D D D D D D D D D D D D D D D D D Max Depth 08/12/15 07:56:24 1/1

58 Manholes Name Ground Subcatchme Elevation nt (Spill Crest) Invert Elevation Max Water Elevation Volume of Ponded Flow Stored Duration of Surcharge (min) sec Rainfall Reference Max Flow cfs EGL Elevation Surcharge at Max HGL D D D Yr SCS D D Yr SCS D D Yr SCS D D D Yr SCS D D D Yr SCS Freeboard 08/12/15 07:53:57 1/1

59 Conduit from D to D Untitled Day [0] Time 00:01:00 Step 1 Conduit 406 from D to D Conduit 404 from D to D D D D D D D D D D D D D D

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61 Pipes Name Upstream Node Name Downstream Node Name Diameter (Height) Length Downstream Invert Elevation Upstream Invert Elevation Maximum Water Elevation (US) Design Full Flow cfs Max Flow cfs Pipe Surcharge at U/S m Duration of Surcharged Flow min 8576 D D D D D D D D D D D D D D D D D D D D D D D D D Max Depth 08/12/15 08:10:42 1/1

62 Manholes Name Subcatchme nt Ground Elevation (Spill Crest) Invert Elevation Max Water Elevation Volume of Ponded Flow Stored ^3 Duration of Surcharge (min) sec Rainfall Reference Max Flow cfs EGL Elevation Surcharge at Max HGL Freeboard D D D Yr SC D D Yr SC D D Yr SC D D D Yr SC D D D Yr SC /12/15 08:09:37 1/1

63 APPENDIX E NEW SYSTEM HYDRAULIC PROFILE

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65 Conduit from D to D Conduit 6 from D to CB5 Untitled Day [0] Time 00:01:00 Step 1 Conduit 406 from D to D Conduit 404 from D to D D D D CB CB CB CB CB D D D D D

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67 Pipes Name Upstream Node Name Downstream Node Name Diameter (Height) Length Downstream Invert Elevation Upstream Invert Elevation Maximum Water Elevation (US) Design Max Full Flow Flow cfs cfs Pipe Surcharge at U/S m 8576 D D D D D D D D D CB1 D CB2 CB CB3 CB CB4 CB CB5 CB D CB D D D D Max Depth 08/14/15 09:25:38 1/1

68 Manholes Name Ground Subcatchme Elevation nt (Spill Crest) Invert Elevation Max Water Elevation Volume of Ponded Flow Stored ^3 Duration of Surcharge (min) sec Rainfall Reference Max Flow cfs EGL Elevation Surcharge at Max HGL D D D Yr SC D D Yr SC CB CB CB CB Yr SC CB Yr SC D D D Yr SC Freeboard 08/14/15 09:15:47 1/1