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HomeMy WebLinkAboutWPO202200038 Correspondence 2022-12-13 (2)ROUDABUSH, GALE & ASSOCIATES, INC. ENGINEERS, SURVEYORS AND LAND PLANNERS 8 P December 08, 2022 Mr. John Anderson Albemarle County Engineering Department 401 McIntire Road Charlottesville, VA 22902 Project Title: Breezy Hill — Breezy Hill WPO Plan (WPO 2022-00038) Mr. Anderson, Please find attached the revised plans for Breezy Hill WPO 2022-00038. The plans have been revised to address the com- ments received from the County of Albemarle's Engineering Department dated October 21', 2022. A. Stormwater Pollution Prevention Plan (SWPPP) Sub SWPPP 1. Please ensure SWPPP cover includes reference to WP0202200038. This has been verified to reference designation 2. Submit SWPPP* using county template located at: https://www.albemarle.org/home/show- pu bl is heddocument/166/638016127329270000 a. Sec. 6.A.: PPP Exhibit: Please show initial location of: i. Rain gauge. ii. Portable sanitary facilities (porta-john), as required. iii. Covered non -hazardous waste dumpster, if required. iv. Vehicle wash waters, draining to trapping measure (Not a sediment trap de- sign, per se, but shallow depression —1-2 backhoe buckets. Avoid direct drain- age to Ex. storm system.) v. Concrete wash -out. vi. On -site fuel, if required. vii. Paint, stucco, chemical storage, if required. Will be submitted with revised WPO b. Sec. 6E: List named individual responsible for PPP measures. Will be Listed c. Sec. 8: Although Albemarle County will inspect, Applicant is required to retain qualified (contractor/third- party) E&S inspection personnel to perform ESC inspections and evaluate compliance relative to VESCH, 3rd Edition, 1992. Notation has been revised d. Sec. 9: Ensure Signed Certification is signed and dated. See Pollution Prevention Plan B. Pollution Prevention Plan (PPP) —See above, item 2.a The PPP content requirements can be found in County Code section 17-404. See Pollution Prevention Plan C. Stormwater Management Plan (SWMP) 1. General a. Include WPO# on plan title sheet, SWPPP cover, and Calc. packet cover: WP0202200038. Revised RGA Comment Responses Page 2 of 10 2. Calculations a. Lack context, narrative summary, compliance tables, energy balance equations, index, TOC, pre - /post -developed drainage maps, VRRM.xIs, or compliance narrative in typical format within a single packet. Instead, 24 files were submitted, including: 21 routings of varying complexity, with no narra- tive or index connection to project plan, or graphic elements of SWM practices; 2 sediment basin design data sheets; VA DEQ Stormwater Design Specification No. 2. Engineering requests a single document that provides items listed as missing or absent such that at plan approval a single docu- ment with cover /title identifying project may be stamped approved, shared, referenced, etc. It is unorthodox to submit routings with no narrative, summary tables, compliance tables /equations (Energy balance; VRRM.xIs, for example), to instead submit 21 separate data input /output files which cannot be interpreted. Please call if questions since plan review is affected. Review of calcula- tions is unavoidably suspended. Additional comments are virtually assured relating to calculations, once received, or relating to elements of BMP design dependent upon calculations. 21 submittals (pg. length): 27, 27, 31, 18, 41, 31, 41, 39, 21, 33, 33, 73, 9, 21, 142, 15, 15, 15, 41, 31, 31.698 total pages is striking. Calcs require x-referencing to plan SWM facilities to serve primary purpose of cal- culations, which is to support and demonstrate compliant design. b. Provide VRRM.xIs for project in Calc. packet. See routing summaries; will be included in SB and ST Design, VRRM spreadsheet and quality & quan- tity narratives on Sheet 5. 3. Sheet 3 a. Please check legend. Confirm 'Perimeter stream' is intentional. Should this label read 'perennial stream'? Revised to read 'perennial stream' b. County GIS /real estate records indicate multiple Carroll Creek Properties, LLC parcels, while existing conditions appears to consolidate these Carroll Creek Properties holdings with Breezy Hill at Keswick TMP 09400-00-00-0o8A0; please revise existing conditions to match current property ownership records unless county GIS /real estate records do not reflect current ownership of parcels (depicted in plan as a single consolidated parcel, sheet 3). Revised to clarify records c. Please ensure clear labeling of stream buffer and floodplain overlay district boundaries. Additional labelling added d. It is not possible to distinguish between Albemarle County preserved steep and critical slopes (leg- end shading virtually identical). Revise shading so possible to distinguish which slopes are critical (rural district), and which are preserved steep (non -rural district). Also applies to sheet 4. Revised for Clarity e. If pipe structure beneath existing gravel road at entrance from Richmond Road is to remain and serve the subdivision, perform engineering evaluation of pipe, including pipe video inspection with Certified Engineers Report that attests to fitness of this existing pipe to serve as primary entrance drainage structure for specified estimated life of service. If projected life of service is less than equivalent expected life of service of new HDPE or RCP drainage pipe, replace existing entrance pipe with new pipe. Provide calculations and details for capacity, velocity, outfall protection, and list pipe L, DIA, and material. Specify end walls or end sections, as needed. Pipe 164C added to replace existing pipe structure. 4. Sheet 4: Coordinate construction access and MOT /work zone measures and device placement with VDOT, as needed, as pre -requisite to WPO plan construction entrance approval. A FT flagger with work zone safety RGA Comment Responses Page 3 of 10 certification /flagger certification maybe required to occupy station at particular times, or all times that con- struction traffic is likely to use this entrance at U.S. Rt. 250. Albemarle defers to VDOT. Additional Sheet added for traffic control notes, exhibit and sign/cone placement. 5. Sheet 11 a. Label streets. Labels added. b. Include Note to contractor that street -facing roofs that contribute storm runoff to (street) inlet /pipe conveyance system drainage areas are to be connected to street inlet /pipe conveyance sys- tems. Single-family residences with front yards draining into the streets typically detail splash blocks, which will be utilized to direct the roof -top areas to the storm -sewer system adequately sized for acceptance. CDA's modified to better define. 6. Sheet 12 a. Circumscribed ditch details partially address need for ditch design stated elsewhere, but these de- tails are confusing. Sheets 17, 18 may provide most detail required. This plan view should identify each ditch by number, by reasonable proposed grading (incl. labeled contours), stationing corre- sponding with sheets 17, 18 ditch lining. Ditch labeling, supporting computations, proposed contours and stationing, 2-yr velocities and 10-yr depths added. b. Provide table on this or other sheet/s that list V2-yr (velocity) for each ditch. Located in Ditch Callout section c. Ensure ditch lining for each ditch section is appropriate for V2-yr peak. Located in Ditch Callout section d. Label streets. Label ponds. Also, item q., next comment. Labels added 7. Sheet 13 a. Provide base of riser footing elevation, Str. 142E, in profile view. Riser footing detail added to Str. 142E b. Provide riser footing dimensions, Str. 142E, in profile view. (L x W x D) Riser footing detail added to Str. 142E c. Provide INV OUT, Str. 142E, in profile view. Invert out from Str. 142E added d. Provide INV IN /OUT, 35'-24" HDPE pipe. INV IN/OUT added to pipe e. Include comprehensive geotechnical notes for re -furbished dam section, including material suitabil- ity, clay core, collars, collar dimensions, inspection, compaction, etc. Notation revised to full replacement unless dam section & improvements are certified by Geo-tech. f. Provide SL-1 labels, profile view, Str. 142C, 1426, in profile view. SL-1 notations added g. Provide Y2 steel plate (labels) in floor of 5tr. 142C, 14213, since vertical difference INV IN-INV OUT>4'. Y2" steel plate labels denoted at Str. 142C & 142B h. Provide buoyancy calculations, riser structures 142E, 142D, since partially submerged. Flowable fill to address buoyancy concerns i. Provide Anti -vortex labels at Str. 142E, 142D. Labels added j. Label'36" by-pass orifice' is unclear; clarify via inset detail installation and INV location of 36" by- pass orifice, especially relative to riser DIA. RGA Comment Responses Page 4 of 10 Additional clarification provided k. Label riser and structure DIA of each vertical structure depicted in profile 142A-142E Profile. Additional clarification provided I. Provide L calculation for salt -treated timber ELS; Note: base L on 10-yr discharge thru pipe. ELS measures revised for accuracy m. Show /label end wall or end section (provide VDOT designation) at outfall of 152' pipe, at Str 142A. Storm structure schedule in support of and consistent w/profiles n. Review /revise 12" pipe sections (152' and 176') downstream of 24" DIA storm pipe. Please ensure plan /profile PIPE DIA views are consistent; for example: 15" in plan v. 12" in profile. Profile & Plan view checked, modified for consistency o. Note: All storm culvert pipe in public drainage easement must be 15" DIA Min. Revised & Noted p. Provide inset detail for 142C that clarifies design intent of this structure, which is labeled 'bypass' in plan view. It is unclear, for example, if 36" orifice will divert a specified volume away from later downstream smaller DIA pipes. Plan /profile /calculations need to guide reviewer, contractor, in - specter, and others with sufficient detail as to what, exactly, is to occur at Str. 142C. Storm Structure Schedule & labels added to clarify q. Please give each on -site existing pond a designation: Pond A, B, C, etc., across all plan sheets, for reference. Pond numbering provided for reference. r. Provide existing contour labels. Additional contour labels added to each sheet 8. Sheet 14 a. Pipe slope 16.97% exceeds ACDSM Drainage Plan checklist for Plan Reviewers Max. 16%. Provide anchors for pipe slope >16%. Ref. VDOT Drainage Manual, 9.4.8.7., p. 9-37. Pipe slopes reduced to less than 16%, and will not require anchoring b. ELS #2 is insufficient length for Q(10) =10.6 cfs. ELS design L: 13' /cfs, with 130' Max. L. Henrico County ELS (#1&2) and DEQ ELS(#3) specifications provided to meet requirements. c. It appears that Str. 146 provides Q(10) bypass of nearly 20cfs, with just 10.6cfs continuing down- stream to Str. 144. By -Pass removed due to lack of adequate outfall d. Provide riprap dimensions for riprap channel downslope of Str. 146. (L x W x D). Outlet Protection & Spillways numbered with inset details e. Provide V2yr design for this riprap channel. N/A f. Provide inset detail for Str. 146 that clearly conveys bypass design. '(2) 24" x 6" weir openings' label in profile view at profile scale is insufficient detail. Provide label on profile, Str. 146, that identifies corresponding routings for V2-yr, Q10-yr, at this bypass location. By -Pass removed due to lack of adequate outfall g. Show in inset profile view for Str. 146 distance from two weir openings to proposed grade; show whether, for example, bypass flow exits weir opening x' above riprap channel, ht. of weir above riprap channel, etc. By -Pass removed due to lack of adequate outfall h. If Bluebird Drive is a public RW, provide public drainage easement over storm pipes that convey run- off from Bluebird Drive inlets to receiving stream. Drainage easements added RGA Comment Responses Page 5 of 10 i. Provide maintenance access to outfall of any pipe that is in public drainage easement, easement to be traversable by vehicle: 10' Min. width, 20% Max. slope Access easements added j. Provide public drainage easement over all storm pipes beyond public RW to point of SWIM detention treatment (existing refurbished ponds, for example), and also over storm pipes beyond public RW to receiving stream/s. Drainage & Access Easements added k. Revise MH spacing between MH 146A and 146 to 300', per VDOT Drainage Manual table 9-3, p. 9-7, Access Hole Spacing. Revised to less than 300 If I. Compare proposed grade downslope of Str 146A in plan /profile. Profile shows embankment not visible in plan view. Revise contours /proposed grading so that plan /profile are consistent at this location. Profile view shows 7' embankment not shown in plan view. Revised for clarity m. 7' embankment in profile view may, with certain storm events, yield 7' ponded depth at this loca- tion. Confirm design intent at this location and suitability of yard swale at this location. Converted to DI-5 for acceptance of rear yard ditch n. Use VDOT nomenclature in all profile views to identify riser type, whether MH, yd grate, or DI. Storm schedule provided o. Provide VDOT LD-204 (inlet design) and LD-229 (culvert design) tables: All inlets /pipes. Provided for all proposed pipes & structures located on this plan p. Certain comments, sheet 12, may apply to sheet 13. For example: i. Provide INV IN /OUT at Str. 146 A (shift proposed grade label so data not obscured). ii. Provide additional existing contour labels in plan view. iii. Label end wall or end section at Str. 146. Use VDOT nomenclature; ES-1 for example. iv. Label riprap dimensions at Str. 144 Additional labeling, nomenclature & clarity provided 9. Sheet 15 a. Consider all comments at sheet 13, 14 that may have bearing on sheet 15, especially: i. SL-1 (Str. 178). ii. %" steel plate in floor of MH (Str. 178, 178A, for example). iii. Max. pipe slope (16.68%for example, exceeds Max.). iv. Pipe anchors for pipe proposed to be installed steeper than 16%. Steel plate, SL-1 & ST-1 notation added to Storm Structure Schedule b. Provide compaction note for fill beneath structures or pipes in fill section (Str. 180, 69' 18"HDPE for example). Note 69'-18" DIA HDPE at this location in this fill section is esp. susceptible to settling, deformity, deflection, and separation at point of connection with Str. 180 MH. Fill shown in profiles & Compaction notation added c. Recommend increase slope of 67' -18" HDPE downstream of 178A to allow slight error during con- struction. Min. pipe slope =0.50% and if As -built condition indicates pipe slope <0.50%, hydraulic analysis of pipe to ensure sufficient capacity and self -scouring velocity will be required prior to facil- ity acceptance, bond release, etc. All pipe slopes increased to greater than 0.50% d. Storm pipe 177A; provide: i. End wall data in plan /profile view. Provide complete dimensional description for end walls (skew, ht., tapered ht., L, wall thickness). End walls appear required at this location RGA Comment Responses Page 6 of 10 ii. In plan view, inlet of pipe appears buried, may fail to extend to proposed grade. Clarify. iii. Specify storm pipe material (plan /profile). iv. Provide clear x-ref. (profile or plan view) to HydroCAD routings for this pipe. EW-1 End walls added for the 36" culvert e. Please eliminate 2 extraneous vertical lines, Sta. 19+60, Strm 190 —178A profile. Removed f. Grading at SWM Outfall 3, stream crossing, creates several steep sections of ditch from road Ditch profile, section callouts and computations added g. elevation to pipe end walls. Provide: i. Labels for these ditches ii. X-sectional design for ditches iii. Ditch lining corresponding with V2-yr, each ditch PG-2A added to catch slope locations at toe of fill at stream crossing 10. Sheet 16 a. Provide ref. to specific outfall protection detail, sheet 20-22, plan view. Label OP# in plan view. Outlet Protection Numbering & insets provided for concentrated outfall locations b. Consider review comments for proposed 114' — 24" HDPE pipe thru embankment /existing dam sec- tion elsewhere, above. Those comments may apply here, as well. Plan view label that reads: 'Exist- ing Dam Section consult w/Geotech to utilize, refurbish & or reconstruct' is insufficient design guid- ance for a dam section upslope of Breezy Hill Lane. Pond WSEL=370.40' is —5' higher than Breezy Hill Lane (see profile). Comprehensive dam embankment refurbishment (design) is required prior to WPO or ROAD plan approval. It may not be coordinated at a later point in time with a geotechnical engineer. Please present dam embankment design for each pond embankment proposed to be cut to install storm pipe. Plan calls for full dam section replacement w/clay core, else proposed alternative is certified by Ge- otechnical Engineer c. Revise 114' — 24" HDPE pipe slope to at least 0.50% Min. slope. Engineering recommends Min. slope of 0.55% or more to allow slight error during construction. HDPE material can deflect and deform. RCP is more resistant to deflection and deformation, but design slope at absolute Min. (0.50%) al- lows no room for error during construction. 0.50% min slope provided on storm sewer pipes d. Provide end wall or end section label at Str. 100, profile view. Use VDOT nomenclature. ES-1, for example. Structure schedule provided with specificity, nomenclature and key construction elevations e. Check all plan profiles, all sheets, for clear outfall protection cross-reference to outfall protection details on sheets 20-22. Outlet Protection Numbering & accompanying insets provided for concentrated outfall locations 11. Sheets 17,18 a. Provide Velocity table for all ditches, all ditch stations; table to include lining appropriate to V2-yr. Computations provided for each ditch under separate cover. b. Provide Cl. 1 riprap dimensions for riprap at each ditch outfall (L x W x D). 18" depth specified. Outlet Protection Numbering & accompanying insets provided for concentrated outfall locations c. c. Sheet 18: Delete Note 1. Deleted 12. Sheets 19 RGA Comment Responses Page 7 of 10 a. Provide plan view for these storm profiles: STRM 190-178A; STRM 164-192A. Missing storm structure plan views added, as appropriate b. Show missing structure, profile view, upstream of 42' -15" DIA HDPE @ 1.20%, and Str. 164. Added c. Note 1., sheet 18, states %" steel plate required at Str. 180, but profile does not appear to indicate diff. INV IN-INV OUT>4'. Please check, revise note as needed. Steel Plate notation added to Storm Structure Schedule on structures containing greater than a 4' drop between inverts d. See prior comments on Max. pipe slope /anchors. 16.68% > Max. pipe slope and requires anchors unless revised to 16%, Max. Revised to less than 16% e. See prior comment on Compaction Note for pipes or structures in fill section. Provide compaction note for pipe sections or structure in fill section. Compaction notation added f. STRM 190 —178A profile appears on Sheet 15. Profile, this sheet, appears to be a duplicate. Delete profile on this sheet unless it presents information not shown on profile on sheet 15. Deleted g. Provide safety slab label (SL-1) for any structure ht. >12' (Str. 156, for example). Notation added to schedule h. Provide pipe DIA, L, slope for pipe downstream of Str. 170. Labeling added i. Provide buoyancy calc. Str. 192, 194. Provided j. Clarify design intent with riprap shown at Str. 194: An emergency spillway, for example. Additional labeling and clarification provided for each Spillway & Outlet Protection location k. Feature labeled SWM #3 requires clarification and x-ref. to HydroCAD routings if it serves a SWM purpose. For example: If SWM #3 is intended to reduce pre- /post-dev 2- or 10-yr Q peak, plan and calculations should present water quantity compliance information as clearly as possible. Ponds are existing and shall function as pass through facilities. All quality and quantity reduction shall be provided via ELS outfalls and FOS dedication I. Note: If any existing pond is to provide storm water quality function, provide detailed design data that corresponds with VA DEQ Stormwater Design Specification No. 14, Wet Pond. N/A 13. Sheet 20 a. For ELS#1, 2, 3: Please disregard design length comments pertaining to Q(10) design L of these ELSs that may appear with review of earlier plan sheets, since appropriate L is presented on this sheet. Apologies for the confusion from mis-matched labels. Resolved. 14. Sheet 21 a. It is unclear how SWM (pond?) design for DAs A, B, C, D reduce TP by 16.56, 5.30, 1.76, 3.26 lb., re- spectively. Provide separate DA A, B, C, D tabs that from VRRM.xIs New Development worksheet that shows clearly which BMP measures in these DAs reduce TP by listed amounts. Include individual DA tabs with BMP measures with Calc. packet, or on the plan. Ponds are existing and shall function as pass through facilities. All quality and quantity reduction shall be provided via ELS outfalls & FOS dedication. See VRRM D. Erosion and Sediment Control Plan (ESCP) 15. Sheet 5 RGA Comment Responses Page 8 of 10 Phase II Sequence Note 2: Provide copy of COE permit (USACE) as prerequisite to WPO plan approval. Since wetland impacts are first initiated in Phase 2 ESC plan, ideally ESC Phase 1 commences prior to receipt of COE per- mit. a. Phase II Sequence Note 10: typo /correct to read: 'Soils on -site are noted to be poor...' Revised b. Phase II Sequence Note 11: revise section to read: 'Install outlet protection at each outfall ...' Revised 16. Sheet 6 a. Revise PLD to include topsoil stockpile area. Done b. Label each sediment trap and sediment basin floor dimensions (L x W). Dimensioned Sediment Traps & Basins c. Depict/label sediment basin riser/outfall pipes (thru embankment): DIA, L, and material type. Labeling of Pipes & Structures added and now include schedule d. Revise stone construction entrance (CE) at U.S. Rt. 250 to paved construction entrance (PCE). Paved construction entrance now depicted e. Include paved wash rack detail on plans. Ref. ACDSM, p. 8. Detail Provided f. Provide SAF/TP orange fencing between PLD and adjacent residential parcel lawn areas. Safety Fence added along property line g. Please provide several proposed contour labels at each sediment trap or basin to aid review, inspec- tion, and bond estimate. Additional contour labels added h. Show sediment basin baffles, if /as needed. N/A 17. Sheet 7 a. Label roads to aid review and for reference. Without labels, for example, difficult to describe next item: b. Road labels added to all relevant sheets for reference b. Ditch labels are confusing. For example, Ditch 1, POA#6, POA#7 are on far side of development from Ditch 1, POA#1. It is not possible for Ditch 1 to exist in locations remote from one another. Ditch 2, POA#6, POA#3: same comment. Please review all ditch labels to ensure ditch locations are clearly understandable, that labels are consistent, and reasonable. Ditch labels added to each sheet and oriented to outfall POA numbers, but should be more readily followed c. Ditches: Refine proposed contours to define ditches. Many ditch labels do not correspond with grad- ing that would establish or suggest or define a ditch. Contours for ditch grading added to plans; Labeled d. Provide clear ditch start -end points. Label all ditches. Provide calculations for all ditches with ditch lining specified to correspond with 2-yr storm event V peak. Provide cross sections /geometry for each proposed ditch: side -slope, width, depth (all ditches). Additional comments possible. Computations for each ditch included in computation package. 2-yr velocity, 10-yr depths added to cal louts. e. ST3 label is obscured by PS symbol. Please shift symbol. Symbol shifted RGA Comment Responses Page 9 of 10 f. STS, ST6 labels are obscured by stream buffer line type or ULD line type. Shift ST labels so more eas- ily readable. Labels shifted g. Note 3: Reassign slope -marking responsibility. Albemarle does not delineate critical or steep slopes in the field. This is a contractor responsibility. Revised note accordingly h. Entrance pipe: Specify new pipe material, length, diameter, end walls or end sections, as needed, at public road entrance at Richmond Rd., U.S. Rt. 250. Also, please see SWMP comment 3.e. if existing pipe is proposed to serve Breezy Hill subdivision. Permanent pipe and outfall added at entrance location i. OP1, OPS, OP6: It is unclear what outfalls are protected by these outfall protection measures. Outlet Protection labels and insets coordinated j. Rectangular hatching denoting potential non-structural fill locations between long parallel streets obscures proposed grade lines /proposed contour labels. Adjust line weight or use alt. shading or line -type to denote potential non-structural fill, this location. Ensure all proposed grade lines and proposed contour labels are easily readable. Hatching and labels revised accordingly k. ST1 is located partially off -site. Provide written agreement with Owner, TMP 94-48, Breezy Hill at Keswick, LLC, to locate ESC measure on this off -site parcel, unless separate plat proposes boundary line adjustment with off -site parcel. Heavy solid line type appears to delineate development parcel, which bisects ST1. Off -site ESC measures require a recorded temporary construction easement, will require off -site owner to be party to WPO plan bond, else a notarized written agreement between owner of off -site parcel and development parcel is required. Owner is Engineering Review Com- ments Page 7 of 8 identical, in this instance. Comment withdrawn if development boundary is clari- fied to include TMP 94-48, thereby locating ST1 wholly within Breezy Hill development. Owner names/TMP numbers resolved to current deeds of ownership. TMP 94-48 shall be split into 2 parcels. (Same owner as Breezy) I. It is unclear how storm pipe leading from inlets on street that runs beneath SB1 can be built while SB1 is performing an ESC function. Clarify via sequence of construction. SB1 will not function as an ESC basin if sequence proposes open cut thru sidewall embankments of SB1 to install a storm line beneath it. Construction sequencing clarified & depicted 18. Sheet 8 a. Revise sediment trap table to list wet and dry volume provided. Added b. Revise sediment basin table to list wet and dry volume required and provided. Added c. Provide sediment basin clean -out elevation. Added d. Provide sediment basin spillway, trench cutoff, collar design (# collars /dimensions), and baffle infor- mation. If baffles are required, show in plan view, sheets 6 and 7. N/A e. Please see sediment basin schematic elevations detail, this sheet, and provide corresponding design elevations. Ensure relevant elevations which may be contained in sediment basin design data sheets submitted as separate calculations appear in the sediment basin design table on sheet 8. Computational Package submitted/coordinated in concert with design revisions RGA Comment Responses Page 10 of 10 f. Sediment trap detail (3.13-2) with No. 1, 2 discrete design information is inconsistent with 9-ST table at bottom of plan sheet. Compare /update 9-ST table as needed, and review recommends eliminate No. 1, 2 ST design data from Sediment Trap detail (3.13-2), center -left, this sheet. Sediment Trap numbering and sizing revised; all design information updated We thank you for taking the time to review these plans and hope to have adequately addressed your comments. Should you need any additional information, please let me know and I'll respond as quickly as possible. Sincerely, Chris Mulligan, P.E.