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Home My WebLink AboutMASON STREET INFRASTRUCTURE PROJECT - FDP230016 - SUBMITTAL DOCUMENTS - ROUND 7 - Geotechnical (Soils) Report Blaine Mathisen From: Erin Bouchet <ebouchet@ctlthompson.com> Sent: Monday, August 5, 2024 5:02 PM To: Reese, Andy; Blaine Mathisen Subject: RE: FCRM Groundwater Categories: Filed by Newforma Here is a table summarizing the groundwater measurements we have taken to-date. Boring Depth to GW(during) Depth to GW Depth to GW Depth to GW Depth to GW Depth to GW (3-21-2024) (3-29-2024) (4-23-2024) (5-28-2024) (6-21-2024) (7-24-2024) P-1 6 5.5 5.5 5.5 5.5 6.5 P-2 5 8 8 8.5 8.5 9 Erin Bouchet, P.E., P.G. Associate Engineer I Denver Engineering Manager CTLIThompson, Inc. 1971 West 12th Avenue Denver, Colorado 80204 Office: 303-825-0777 Direct: 303-628-5025 ebouchet&ctlthompson.com I www.ctlt.com CTL THOMPSON CTLITHOMPSON April 19, 2024 1311 North College, LLC 262 East Mountain Avenue Fort Collins, Colorado 80524 Attention: Colin Vito Subject: Groundwater Investigation Fort Collins Rescue Mission 1311 North College Avenue Fort Collins, Colorado Project No. FC10520.002-112-L1 We performed a Geotechnical Investigation for Fort Collins Rescue Mission initially called Hibdon/Mason 24/7 Shelter and presented results in a report (Project No. FC10,520-125-R1 , dated November 20, 2023). During the investigation, ground- water was encountered at depths of 8 to 9.5 feet or approximate elevations 4970.5' to 4973'. We indicated that groundwater may be encountered during sub-excavation or deep utility installation. We were requested to drill additional borings to further evaluate the groundwater levels near the proposed detention pond. This letter pre- sents the results of our additional groundwater measurements. The scope was de- scribed in a proposal DN 24-0094R dated March 1 , 2024. Investigation We drilled two borings on March 21 st 2024, to a depth of about 15 feet below existing grade using a truck-mounted drill rig and 8-inch continuous flight hollow- stem auger at the approximate locations shown on Fig. 1 . Machine-slotted PVC pipe was installed in the lower 10 feet and the upper 5 feet is solid PVC riser pipe. An ad- ditional 3.5 feet of riser pipe was installed above-grade with a stick-up well protector. Silica sand was placed from a depth of 3 feet to 15 feet. A bentonite seal was con- structed in the upper 3 feet of each monitoring well. Our field representative was pre- sent to observe drilling, log the strata encountered, and log monitoring well construc- tion. Monitoring well logs are presented in Appendix A. Subsurface Conditions Strata found in our exploratory borings consisted of about 7 to 9.5 feet of sandy gravelly clay underlain by silty gravelly sand. We measured groundwater at the time of drilling and once again, several days later on March 29, 2024. The groundwater measurements are presented in the table below. Additional groundwa- ter measurements will be obtained on a monthly basis through the fall of 2024 and measurements will be transmitted in subsequent letters. CTLIThompson, Inc. Denver, Fort Collins, Colorado Springs, Glenwood Springs, Pueblo, Summit County—Colorado Cheyenne, Wyoming and Bozeman, Montana Monitoring Well March 21, 2024 March 29, 2024 GW Elev. (shallow- Depth to GW During Depth to GW (ft) est measurement) Drilling (ft) (ft) P-1 6 5.5 4974 P-2 5 8 4971.5 We believe this investigation was conducted with that level of skill and care ordinarily used by geotechnical engineers practicing under similar conditions. No warranty, express or implied is made. If we can be of further service in discussing the contents of this letter or in the analysis of the influence of subsoil conditions on design of the structures, please call. 0 Up CTL I THOMPSON, INC. O•�STINE'•'t'�, � eo 0 z 0054368 0: Abhinav Jakilati Staff Engineer Reviewed by: S /ONAt-� Erin Bouchet, P.E., P.G. Associate Engineer) Denver Engineering Manager 4/zz/zoz4 Via e-mail: Andy.Reese(a�kimley-horn.com Blaine.Math isen(cD-epsgroupinc.com 1311 NORTH COLLEGE,LLC 2 FORT COLLINS RESCUE MISSION-1311 NORTH COLLEGE AVENUE CTL I T PROJECT NO.FC10520.002-112-L1 W. WILLOX LN. LEGEND: P1 APPROXIMATE LOCATION OF SITE z • EXPLORATORY BORING 0 r 0 100 200 r m 0 m SCALE: 1" = 200' HICKORY ST. m VICINITY MAP NOT TO SCALE r r • � i irr�Y : a 1� P-1 _ . •I sop z r ArA 1. �.e rIlkr ; S -�` HICKORY sr. Locations of 1311 NORTH COLLEGE, LLC Exploratory FORT COLLINS RESCUE MISSION CTLIT Project No. FC10520.002-112-L1 Borings Fig. 1 APPENDIX A MONITORING WELL LOGS 1311 NORTH COLLEGE,LLC FORT COLLINS RESCUE MISSION-1311 NORTH COLLEGE AVENUE CTL IT PROJECT NO.FC10520.002-112-L1 Monitoring Well CTUTHOMPSON, INC. (303)825-0777 Construction Summary 1971 WEST 12TH AVENUE DENVER,COLORADO 80204 Project No. FC10520.002-112 Well No. P-1 Project Name FORT COLLINS RESCUE MISSION Engineer TSK/DENVER Drilling Contractor TERRACON Date Drilled 3/21/24 Drilling Method 8"HOLLOW STEM AUGER Ground Elevation 4979.81' Ground Water Depth(ft) 6' WELL CONSTRUCTION WELL DETAIL DEPTH/HEIGHT FROM GROUND SURFACE Cap Type J-PLUG DEPTH (FT) Well Protector Type STICK UP 4' Top of Well Protector Annular Sealant Type BENTONITE CHIPS 3.5, Top of Riser Pipe Seal Material Type BENTONITE CHIPS 0' Ground Surface Sand Pack Type SILICA 10/20 Riser Pipe Length(ft)and Type 5'PVC 40 Riser Pipe Diameter(in) 2^ Screen Length(ft)and Type 10'PVC 40 Screen Slot Size 0.0101, Gallons Removed(purge) N/A Other N/A DEPTH (FEET) 01 Top of Seal 3' Total Seal Interval De th Soil From To Type Soil Description 3 Top of Sand 0' 0' TS NATURAL GRASS 5' Top of Screen 0' 9.5' CL CLAY,SANDY,MOIST,DARK BROWN. 9.5' 15' SPG SAND,GRAVELLY,VERY MOIST, 12' Sand Pack BROWN,DARK BROWN. 10, Total Screen Interval 15' Bottom of Screen �f 15' Bottom of Borehole REMARKS: g" Borehole Diameter(in) FIG.A-1 Monitoring Well CTUTHOMPSON, INC. (303)825-0777 Construction Summary 1971 WEST 12TH AVENUE DENVER,COLORADO 80204 Project No. FC10520.002-112 Well No. P-2 Project Name FORT COLLINS RESCUE MISSION Engineer TSK/DENVER Drilling Contractor TERRACON Date Drilled 3/21/24 Drilling Method 8"HOLLOW STEM AUGER Ground Elevation 4979.46' Ground Water Depth(ft) 5' WELL CONSTRUCTION WELL DETAIL DEPTH/HEIGHT FROM GROUND SURFACE Cap Type J-PLUG DEPTH (FT) Well Protector Type STICK UP 4' Top of Well Protector Annular Sealant Type BENTONITE CHIPS 3.5, Top of Riser Pipe Seal Material Type BENTONITE CHIPS 0' Ground Surface Sand Pack Type SILICA 10/20 Riser Pipe Length(ft)and Type 5'PVC 40 Riser Pipe Diameter(in) 2^ Screen Length(ft)and Type 10'PVC 40 Screen Slot Size 0.0101, Gallons Removed(purge) N/A Other N/A DEPTH (FEET) 01 Top of Seal 3' Total Seal Interval De th Soil From To Type Soil Description 3 Top of Sand 0' 0' TS NATURAL GRASS 5' Top of Screen 0' 2.5' CL CLAY,SANDY,MOIST,DARK BROWN. 2.5' 7' CL/GC CLAYEY,GRAVELLY,SANDY 12' Sand Pack 7' 15' SP SAND,GRAVEL,VERY MOIST 10, Total Screen Interval 15, Bottom of Screen �f 15' Bottom of Borehole REMARKS: g" Borehole Diameter(in) FIG.A-2