The URL can be used to link to this page

05.13.2013-PlatatWoodway_DFR_1_LBK-special inspect-pit drain (2).pdf FIELD REPORT Page 1of 4 911 Fifth AvenueDateProject NameProject No. Kirkland, Washington 98033 5/13/2013Plat at Woodway ElementaryKH060644B P: 425-827-7701 LocationMunicipalityWeather th F: 425-827-542423708 104Ave West, Showers/50- EdmondsCity of Edmonds60s www.aesgeo.com Permit No.DPD No.Report No. 1 TO:Engineer/Architect Burnstead Construction CompanyThe Blueline Group th Client/Owner 119880 NE 24Street, Suite 200 Bellevue, WA 98005 Burnstead Construction Company General Contractor/Superintendent ATTN:Ms. Tiffiny Brown AS REQUESTED BY:Curtis Koger EarthworkContractor/Superintendent TE Briggs Construction/Tracy THE FOLLOWING WAS NOTED: Associated Earth Sciences, Inc. (AESI) was onsite part time today at the client’s request to observe the construction of a pit drain located in the infiltration vault, and the preform infiltration rate flow testing in the pit drain. Infiltration Vault and Pit DrainBackground The current design plans include aninfiltration vault. The vault will be a below grade structure with cast-in-pace concrete walls, precast concrete roof panels, and an open base through which storm water will be allowed to infiltration into the sediments and a pit drain below the vault. The pit drain will consist of a pit excavated below the floor elevation of the vault and backfilled with pea gravel. Backfill specifications were provided in our Technical Memorandum dated May 7, 2013. Pit Drain Construction Prior to pit drain construction, the infiltration vault was excavated to approximately 0.5-foot of the final grade, which was measured by the earthwork contractor, and roughly corresponds to319 feet (ft) above mean sea level (amsl). We understand the earthwork contractor plans to finish final grading of the vault after the majority of construction activities utilizing heavy equipment havebeen completed in order to protect the vault subgrade from contamination. The pit drain was excavated using a track-mounted excavator (John Deere 450C LC) with a 32-inch wide bucket with teeth.The pit drainwas excavated to approximately 16 ft below existing grade along the sidewalls, and 17 ft below existing grade in the center. Based on a review of the plans and survey staking, these depths would correspond to303.5 and 302.5 ft amsl, respectively. The footprint of the pit was excavated to approximately 3 wide by 10 ft longat the bottom of the pit, and 4wideby 12 ft longat the top. A 2-inch diameter polyvinylchloride (PVC) piezometerwas placed roughly in the center of the pit to facility water level observation during testing. The total length of the piezometer was 20 feet, and included 5-ft of 0.020-inch machine slotted well screen at the bottom with a threaded cap, and 15-ft of blank well casing with threaded connections.The pit drain was backfilled with washed pea gravel to 318 ft amsl, and 4 x 8 sand from 318 to 319 ft amsl. Pit Drain Testing Mehodology Generally, the infiltration testing method consists of introducing water from a water truck provided by TE Briggs through an electronic flow meter with instantaneous and total flow readout and into the pea gravel via a 2-inch diameter hose placed into the gravel pack. The water level in the pits was monitored in the PVC sounding pipes, placed on the bottom of the pit, with an electronic water level meter. Water was introducedintothe pit until the water truck was out of water. Following the discontinuation of water Copies To:Field Rep:Lara B. Koger Date Mailed:Principal / PM:Curtis J. Koger, L.G., L.E.G., L.Hg. AESI FIELD REPORT Page 2of 4 To:Distribution ListProject Name:Plat at Woodway Elementary Date:May 13, 2013Project No.:KH060644B Permit No.DPD No. flow, water levels were monitoring with the electronic water level meteruntil no water was measurable in the piezometer, approximately 40 minutes. Pit Drain Testing Details and Results We understand that the design flow rate for the infiltration vaultand pit drain is 7 inches per hour (iph). As presented in Table 1,the measured field rate was approximately 33iph. The maximum water level reached during testing was 10.5 ft below the existing ground surface,or approximately 6.5 ft above the bottom of the pit drains. Table 1 Pit Drain Testing Summary Maximum Water Maximum Water Total Water Used Average Flow Equivalent Field Design Rate Level (ft from Level from Base of (gallons)Rate Rate (inches/hour)(inches/hour) existing grade)Pit Drain (ft)(gallons/minute) 10.56.51,55093337 Attachments: Pit Drain Schematic Copies To:Field Rep:Lara Koger Date Mailed: Principal/PM:Curtis Koger, L.G., L.E.G., L.Hg. Ѝ ƚŅ Ќ tğŭĻ at Woodway Elementary KH060644B ŅĻĻƷ Plat ЊА {ƚǒƷŷ ŅĻĻƷ ЊЏ ŅĻĻƷ Ѝ ŅĻĻƷ Ќ bƚƩƷŷ ŅĻĻƷ ƒğ ƚŅ ŅĻĻƷ ğƓķ ŅĻĻƷ źƓĭŷ βЌЊВ͵Ў ƚƓƭ ЌЊВ ĭğƦ Љ͵ЉЋЉЊЎ 9ƌĻǝ͵ ĻƓķ ĭƚƓƓĻĭ 9ƌĻǝ͵ ğƓķ ƚŅĭğƭźƓŭͳ ƭĭƩĻĻƓͲ CƌƚƚƩ CƌƚƚƩ ŅĻĻƷ ƷŷƩĻğķĻķ ğǒƌƷ ǞĻƌƌ Ў ğǒƌƷ ƭƌƚƷ t/Ͳ May 13, 2013 ĬƌğƓƉ CźƓźƭŷĻķ ĭŷźƓĻ Ɠŭ źƓĭŷ 9ǣźƭ Ћ Ѝ ƚŅ Ѝ ŅĻĻƷ tğŭĻ at Woodway Elementary ЊА ŅĻĻƷ 9ğƭƷ KH060644B ЊЏ Plat ŅĻĻƷ ЊЉ ŅĻĻƷ ЊЋ ĻƭƷ ŅĻĻƷ ƒğ ƚŅ ŅĻĻƷ ğƓķ ŅĻĻƷ źƓĭŷ βЌЊВ͵Ў ƚƓƭ ЌЊВ ĭğƦ Љ͵ЉЋЉЊЎ 9ƌĻǝ͵ ĻƓķ ĭƚƓƓĻĭ 9ƌĻǝ͵ ğƓķ ƚŅĭğƭźƓŭͳ ƭĭƩĻĻƓͲ CƌƚƚƩ CƌƚƚƩ ŅĻĻƷ ƷŷƩĻğķĻķ ğǒƌƷ ǞĻƌƌ Ў ğǒƌƷ ƭƌƚƷ t/Ͳ May 13, 2013 ĬƌğƓƉ CźƓźƭŷĻķ ĭŷźƓĻ Ɠŭ źƓĭŷ 9ǣźƭ Ћ