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Home My WebLink About20150615 Ver 1_Wet Pond Calcs 12152015_20160404 Strickland, Bev From:Devane, Boyd Sent:Friday, April 08, 2016 1:23 PM To:Strickland, Bev Subject:FW: Rockingham Grocery stormwater plans #15-0615 Attachments:Rockingham Wet Pond Calcs 12152015.pdf Please file this note and attachment. Thanks NC Division of Water Resources 919-807-6420 From: Devane, Boyd Sent: Monday, April 04, 2016 3:23 PM To: 'Brian O'Kane' <bokane@bohlereng.com> Cc: Turlington, Chad <chad.turlington@ncdenr.gov> Subject: FW: Rockingham Grocery stormwater plans #15-0615 th The Wet Pond calculations page in March 24 Letter of Transmittal had two pages entitled “Wet Detention Basin Design”. Did you omit the second page in your submittal on Friday? NC Division of Water Resources 919-807-6420 From: Brian O'Kane \[mailto:bokane@bohlereng.com\] Sent: Friday, April 01, 2016 7:36 AM To: Devane, Boyd <boyd.devane@ncdenr.gov> Cc: Turlington, Chad <chad.turlington@ncdenr.gov> Subject: RE: Rockingham Grocery stormwater plans #15-0615 Boyd – Here’s a copy of the latest spreadsheet in PDF version. We had to reduce the size of the draw-down orifice to 1” to meet the requirements for draw-down time. We will update the plan sheet accordingly and get you updated copies. Let me know if you see anything else that you need changed or if you want us to make this change and resend the sheets. Thanks! Brian From: Devane, Boyd \[mailto:boyd.devane@ncdenr.gov\] Sent: Thursday, March 31, 2016 2:30 PM To: Brian O'Kane <bokane@bohlereng.com> Cc: Turlington, Chad <chad.turlington@ncdenr.gov> Subject: RE: Rockingham Grocery stormwater plans #15-0615 Just wanted to let you know that I never received anything you were going to send last Thursday. Did you send it? NC Division of Water Resources 919-807-6420 1 From: Brian O'Kane \[mailto:bokane@bohlereng.com\] Sent: Monday, March 28, 2016 7:49 AM To: Devane, Boyd <boyd.devane@ncdenr.gov> Cc: Turlington, Chad <chad.turlington@ncdenr.gov> Subject: RE: Rockingham Grocery stormwater plans #15-0615 Thanks Boyd. I will send them over to you today. From: Devane, Boyd \[mailto:boyd.devane@ncdenr.gov\] Sent: Thursday, March 24, 2016 5:18 PM To: Brian O'Kane <bokane@bohlereng.com> Cc: Turlington, Chad <chad.turlington@ncdenr.gov> Subject: Rockingham Grocery stormwater plans #15-0615 Today, I received four copies of the drawings for the stormwater plan for the Rockingham Grocery project. The plans did not include an updated “Wet Detention Basin Design” calculations sheet. We received a copy of the calculations that was dated Dec 18, 2015 but it does not seem to have been updated to reflect the drawings. In just a quick look, I did th notice the orifice drawings showed a 1.5” draw-down orifice and the December 18 Wet Detention Basin Design sheets showed a 1.0” draw-down orifice. Please send me copy of the engineering calculations for the wet detention basin that you intend to apply to the drawings that I received today. You can email them to me at boyd.devane@ncdenr.gov. Thanks NC Division of Water Resources 919-807-6420 2 BCH LER V N C I N E I'. R f N C Wet Detention Basin Design 1.0 inch Volume Elevation Required Temporary Pool Volume = 7,156 cu ft Temporary Pool Lower Elevation Bound = 260.00 Temporary Pool Upper Elevation Bound = 261.00 Temporary Pool Lower Volume Bound = 5,186 cu ft Temporary Pool Upper Volume Bound = 12,052 cu ft Temporary Pool Elevation = 260.29 Orifice Sizing - Wet Detention 02 Days = 0.0415 cfs 05 Days = 0.0124 cfs Orifice Size = 1.00 in Driving Head (Hc) = 0.42 ft O orifice = 0.017 cfs Drawdown Time = 3.7 days less than 5 days (yes/no) ? Yes 0 greater than 2 days (yes/no) ? Yes 259.50 Anti -Flotation Device 2,470 2,470 Outside Length = 4.00 ft Outside Width = 4.00 ft Inside Length = 3.00 ft Inside Width = 3.00 ft 6745 Bottom Thickness = 0.50 ft Top of Riser = 261.00 ft Invert of Riser = 257.97 ft Area = 16.0 sf Volume = 56 cf Weight = 3,524 lbs Factor of Safety = 1.10 WT Req'd of Anti -Flotation Device = 3,877 lbs Volume of Concrete Req'd = 44.3 cf Depth Provided = 1.00 ft Volume Provided = 45.2 cf WT of Anti -Flotation Device Provided = 3,960 lbs Contour Contour Area Incremental Accumulated Volume Volume, S Stage, Z sq ft cu ft cu ft ft 259.00 4302 0 0 0.0 259.50 5577 2,470 2,470 0.5 260.00 6045 2,906 5,375 1.0 260.29 6335 1,795 7,170 1.3 261.00 6745 4,643 11,814 2.0 262.00 7565 7,155 18,969 3.0 263.00 8425 7,995 26,964 4.0 264.00 9325 8,875 35,839 5.0 (Flowrate required for a 2 day drawdown) (Flowrate required for a 5 day drawdown) (Diameter) 0 (Outside Dim. = 4 -ft x 4 -ft, Inside Dim. = 3 -ft x 3 -ft) (Water Displaced - Top of Riser to Bottom of Riser) (Weight Water Displaced) (Unit WT of Concrete = 150 pcf) Submerged Concrete Unit Weight 87.6 pcf (4 -ft x 4 -ft Box filled 1.00 -ft deep with concrete) OK )rebav volume Contour Contour Area Accumulat Increment ed al Volume Volume, S Stage, Z sq ft cu ft cu ft ft 255.00 99 0 0 0.0 256.00 222 161 161 1.0 257.00 379 301 461 2.0 258.00 569 474 935 3.0 259.00 789 679 1,614 4.0 Contour Contour Area Accumulat Increment ed al Volume Volume, S Stage, Z sq ft cu ft cu ft ft 253.00 106 0 0 0.0 254.00 301 204 204 1.0 255.00 590 446 649 2.0 256.00 962 776 1,425 3.0 257.00 1,600 1,281 2,706 4.0 258.00 2,176 1,888 4,594 5.0 258.50 2,481 1,164 5,758 5.5 259.00 3,513 1,499 7,257 6.0