Loading...
HomeMy WebLinkAboutWPO201400093 Application 2015-01-29 t r 0 ALg� Virginia Erosion and Sediment Control Program (VESCP) for Albemarle County -: ® ,y (This application is only to be used for projects exempt from the Virginia Stormwater Management Program,VSMP, and the DEQ General Permit) Safe Routes to School Sidewalk Project Project Name: (The name should be the same as it appears on plans) Is this an amendment to an approved plan? Yes El No jl Is this a revision or resubmission for review? Yes q No ❑ County File Number: WPO-2014000093 (to be provided by the County for new applications) The following are required elements of new applications[from code section 17-4011. For revisions or amendments,please indicate which items are being amended. Signatures must be provided for any submission. ❑ A. Signature of the Property Owner for each parcel: (Required with every submission or revision, NOT TO BE SIGNED BY AN AGENT OR CONSULTANT) By signing this application as the owner,I hereby certify that all requirements of these plans and permits will be complied with,and I have the authority to authorize the land disturbing activities and development on the subject property. I hereby grant the County of Albemarle the right to enter upon the property as required to ensure compliance with the approved plans and permits. Tax Map&Parcel Print Name of Property Owner Signature of Owner Date Tax Map&Parcel Print Name of Property Owner Signature of Owner Date Tax Map&Parcel Print Name of Property Owner Signature of Owner Date Tax Map&Parcel Print Name of Property Owner Signature of Owner Date Contact Information for the Owner(s)to receive correspondence: Frank Pohl Print Name Address Office of Facilities Development, Rm 228 City State Zip Daytime Phone( ) ext. 7914 E-mail fpohl @albemarle.org 7/1/14,Revised: 7/10/14 Page 1 of 2 f t ❑ B. All Fees [Code section 17-207] Total acres proposed to be disturbed Acres to be disturbed Total Fee Less than 1 $150 per review More than 1 $300 per review For amendments to an approved plan; $200 per review Exceptions; $240 Mitigation Plan;$150 Construction Record Drawing; $300 Provide 2 copies of all plans and any supporting documents. Professional seals must have original signatures. Additional information if not provided on plans and documents: Name of a Contact Person for correspondence(usually the plan preparer,consultant or agent) Print Name Frank Pohl (OFD) Address County of Albemarle, Office of Facilities Development City State Zip Daytime Phone( ) Ext. 7914 E-mail fpohl @albemarle.org *When applications and plans are reviewed,but not approved,and a response to comments is not received within 6 months from the date of county comments,the application will be deemed withdrawn. Applications without valid owner's signatures will not be considered valid. FOR OFFICE USE ONLY WPO# Fee Amount$ Date Paid By who? Receipt# Ck# By: 7/1/14,Revised: 7/10/14 Page 2 of 2 ANHOLD ASSOCIATES Transmittal To: Ms. Michelle Roberge From: David T.Anhold,ASLA County of Albemarle Date: January 29,2015 Dept.of Community Development Pages: Safe Routes to School Sidewalk Project CC: Mr.Jack Kelsey,Alb.County Re: WP02014-000093 Mr. Frank Pohl,Alb. County Revised E&S Plans Mr.Jim Taggart,TCS Eng. 0 Your Use Q For Review ❑ Please Comment ❑ Please Reply ❑ Please Recycle Dear Michelle, Attached are two copies of the revised plans along with engineering support documents that address your plan review comments dated December 22, 2014. Your comments have been addressed as noted below: Erosion and Sediment Control Plan 1. Comment: Show outlet protection on TMP 56-64. Also, the culvert to TMP56- 64 is existing. Please show that there is an adequate channel. There should also be a drainage easement through this property. Response: As this is a very old public road, there is not a recorded drainage easement for the existing culvert. However, it is owned by VDOT. And, based on Mr. Kelsey's conversations with the Local District Engineer and the District Hydraulic Engineer, VDOT has permanent access and maintenance rights as provided by the laws of the State of Virginia. Based on detailed drainage analysis performed by Mr. Taggart, PE, there is actually a small, postdevelopment decrease in the culvert flow(0.02 cfs). In addition, our site inspections show that there is no current erosion at the existing culvert outfall or in the drainage channel located in the hayfield. Therefore we feel these points prove that the existing channel is adequate for our project and that no additional outlet protection measures are required. Landscape Architecture+Planning 8311 Rockfish Gap Tpke. Greenwood,VA 22943 V/F:540.456.6422 M:434.882.3420 danhold @hughes.net The attached documents and following summary comments were prepared by Mr. Taggart, PE. Attached Documents include: 1. Predeveloped Hydrology for the existing culvert(1 yr. event). 2. Predeveloped Culvert profile with Hydraulics for existing culvert(1 yr. event) 3. Postdeveloped Storm sewer analysis for the outfall pipe (remnants of the existing) (1 yr. event) (Same base data as on current plan DOT report) In short the analysis shows: 1. Predeveloped DA=4.88 ac., composite"c"= 0.55, Tc(pre)= 15min (TR-55 included), Q-1yr=6.97cfs 2. Postdeveloped DA=4.88 ac., composite "c"= 0.555, Tc(post)=20min (See DOT report), Q-1 yr=6.95cfs 3. Decrease in 1 year flow= 0.29% The pre/post analysis came out as essentially the same. I think this calculation falls into the margin of error of Tc calcs. The base data for the post developed is the same as that shown on the current storm sewer tabulation,just rerun using a 1 year event. That base data was user-defined at 20 minutes for the largest drainage area. The Tc for the predeveloped was recalculated using TR-55 (copy attached). The lower reach in the TR-55 calcs was a bit steeper in the predeveloped condition because of the regrading and change over from a culvert headwall to an inlet. While that change in lower reach slope reduced the Tc to 15 min, that same level of detail for Tc was not considered in the original design of the storm sewer. 2. Comment: On sheet S-3, please use bold lettering for the following: "PERMANENT DRAINAGE ESMT", 5' TEMPORARY CONSTRUCTION ESMT," and "PROPERTY ACQUISTION."Also show a darker lineweight for the new property line. Response: Bold letting added as requested and a darker lineweight was used for the property line. 3. Comment: On sheet S-3, please provide the following: a) Comment: Place a note for contractor to place inlet#6 at lowest spot of vertical curve or label low spot with a spot elevation. Response: The survey shows a nearby low spot elevation of 703.37. The proposed inlet top equals 703.67' with a corresponding throat r, ,` ., ; � ��/ elevation of 703.17' (not including localized depression). So based on i these elevations the inlet will be the low spot. We have added a note gam` however that reads "Contractor shall adjust pavements as necessary to ensure the curb low spot is at the inlet and there is positive drainage to the inlet." b) Comment: For end section #1 and #7, please make note consistent. For example, the note should state ES-1 with EC-1 Class A-1, Detail 1. Page 2 Response: Made revision as requested. c) Comment: Darken lineweight for proposed underdrains on plan. Response: Made revision as requested. d) Comment: There is a 12" pipe being removed from an existing driveway, but it is not shown as being replaced when the driveway is repaved. Please clarify. Also show how the swale will be revised for runoff to enter Str-5. Response: A shallow grass swale will replace the existing pipe. Surface runoff will drain across the new entrance toward Structure #5. Added flowline and note to clarify proposed conditions. / -) No+ access 4, S(At. ran-(a 1s a(© (iae �: e} Comment: Show drainage easements within �nty property for the drainage swale. Show for two other private properties: TMP56-64 and TMP56-56 Response: The County does not require public use easements on County owned property. Because, in the deed of easement, the County of Albemarle would be both the Grantor and Grantee (i.e. the County granting an easement to itself). For TMP56-64 easement, see item #1 above. For TMP56B-56, the proposed swale is located within the public right-of-way and the new permanent drainage easement around inlet#5. Praioac _ egSer 5 7C( 0,Q 4n01,(45 �re'en 4 of2S-Irac-liert trs,'rCy '' Comment. Show check dams instead of silt fences near the two outlet.iv protection. Show downstream of proposed outlet protection. That way u� `n g( Av,„you can reuse stones from check dam for the outlet protection when ready to stabilize swale. eow wf/1 7 WUL- -no/h� fs .6.rJ1 Response: Replaced silt fence with check dams as requested. tfvn 9 4. Comment: On sheet S-6 move DA 3 notes so that it is legible. Response: Note was moved as requested. 5. Comment: The profile notes for the structures are difficult to read. Please clean up notes or reduce lineweight. Response: Notes where revised as requested. END OF TRANSMITTAL Page 3 `rr r.r TR55 Tc Worksheet Hydraflow Express by Intelisolve Rational Crozet SRTS Inlet 4 PreDev. Peak Description A B C Totals Sheet Flow Manning's n-value = 0.240 0.240 0.011 Flow length (ft) = 200.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 3.70 0.00 0.00 Land slope (%) = 7.80 0.00 0.00 Travel Time (min) = 13.41 + 0.00 + 0.00 = 13.41 Shallow Concentrated Flow Flow length (ft) = 496.00 0.00 0.00 Watercourse slope (%) = 7.80 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) = 4.51 0.00 0.00 Travel Time (min) = 1.83 + 0.00 + 0.00 = 1.83 Channel Flow X sectional flow area ((sqft)) = 0.00 0.00 0.00 Wetted perimeter ((ft)) = 0.00 0.00 0.00 Channel slope (%) = 0.00 0.00 0.00 Manning's n-value = 0.015 0.015 0.015 Velocity (ft/s) = 0.00 0.00 0.00 Flow length (ft) = 0.0 0.0 0.0 Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00 Total Travel Time, Tc 15.00 min Hydrology Report Hydraflow Express by Intelisolve Tuesday, Jan 27 2015 Crozet SRTS Inlet 4 PreDev. Peak Hydrograph type = Rational Peak discharge (cfs) = 6.970 Storm frequency (yrs) = 1 Time interval (min) = 1 Drainage area (ac) = 4.880 Runoff coeff. (C) = 0.55 Rainfall Inten (in/hr) = 2.597 Tc by TR55 (min) = 15 IDF Curve = Albmrle.IDF Rec limb factor = 1.67 Hydrograph Volume=8,375(cuft);0.192(acfl Runoff Hydrograph Q (cfs) 1-yr frequency Q (cfs) 7.00 7.00 6.00 6.00 5.00 5.00 -- -- -- ------ -------- ------ ---- -------- -------- ----- ---- 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0 5 10 15 20 25 30 35 40 Time (min) ammo Runoff Hyd- Qp = 6.97 (cfs) . , N...., ,....., Culvert Report Hydraflow Express by Intelisolve Tuesday,Jan 27 2015 Crozet Ave. SRTS project 25+32- lyr. Event PreDev. Invert Elev Dn (ft) = 699.81 Calculations Pipe Length (ft) = 53.00 Qmin (cfs) = 6.67 Slope (%) = 0.42 Qmax (cfs) = 6.67 Invert Elev Up (ft) = 700.03 Tailwater Elev (ft) = (dc+D)/2 Rise (in) = 24.0 Shape = Cir Highlighted Span (in) = 24.0 Qtotal (cfs) = 6.67 No. Barrels = 1 Qpipe (cfs) = 6.67 n-Value = 0.011 Qovertop (cfs) = 0.00 Inlet Edge = Projecting Veloc Dn (ft/s) = 2.72 Coeff. K,M,c,Y,k = 0.0045, 2, 0.0317, 0.69, 0.5 Veloc Up (ft/s) = 3.24 HGL Dn (ft) = 701.27 Embankment HGL Up (ft) = 701.28 Top Elevation (ft) = 703.52 Hw Elev (ft) = 701.36 Top Width (ft) = 23.00 Hw/D (ft) = 0.66 Crest Width (ft) = 125.00 Flow Regime = Outlet Control Ekvat3 Crozet Ave.SFIT8 project 25+3Z-- 1 yr,Event PreDev.. 14v Depth in) MA 00 157 -- -—- 70300 Z57 --- v•`...*N,i;r , ;‘,1 ..'+T-7'1' '4,1''''' kt'r, ;P`n't "...; V.f,t"4"1,E 11WrkarrIZ apvtivje"rmipRoftr6,1 irt, ^ FS,,,,,, I at wrioi :1„,#,:4::A.,,,,,I,;,-,-,,,411.--ig,..":1,-,4,6-7:,r. as7 ',rt~titoiNe4P14,A='... .t, ..„. ■'''''',, 44,1 ,,,,. [: ,: , -a,4,,.,;41,-:::ct":,.., -,6,,,,,-4.,4,,,,, -,,,,,iiiit ,'0,-.1:41..X' t=4:-.:‘' ''‘it+11' ',A'''' iltiff,1,, ' ' ,•'7.''' L 4108 6-91.00 II' 1 ca sst.00 -203 0 5 10 15 20 25 30 35 40 45 50 55 ED 65 70 75 CI DAV t HUI. .------Embank Reach Iftl • d s o N l6 a S o v 00 0 d N C a 0 J 3 8 O m O N € O > M N 2 co 2 . - co o W MO O E N- 62 N = ca O a C _ C O CD N- CO Q = M N O W J 0 rn 2 c -- N G E:-, p t` 4 I1 co N .0 m c a d O = _ W O "c5 N .. II y O J N > W C Q - C) E U C.0 Z I I C.) 0 . 0 ° O O Q N O = a E N = in .-E N a N 0 co d Tu N O c > = M O 0.F_ .4 d U w _�• v E co H V C C f6 C i O v c N Ey H N E N c O } N N `- ✓ II ~ y C O O C E N d n c O x F N Q' R co a) tri • a C O `v O < O ^ c U co � ii ce V O + CU N @ .- co ,P C% O N L. ^ Q ~ v c W Of co O C :0 6 H o CL w a) ' ) C _ N I U y c c d c O ° /♦�•+ w c .° o V♦ . O n_ Z