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HomeMy WebLinkAboutSite Certifications - 11/16/2018 FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com October 29, 2018 Mrs. Heather McDowell City of Fort Collins 700 Wood Street Fort Collins, Colorado 80521 RE: Site Certification for Maple Mixed Use Fort Collins, Colorado Dear Heather: This drainage certification letter is provided to verify as-constructed conditions for Maple Mixed Use. Northern Engineering completed survey work October 4, 2018 to verify general compliance with the Final Utility Plans for Maple Mixed use dated November 11, 2016, including revised drawings dated 6/05/2018, 7/26/2018, 8/7/2018, and 8/28/2018 by Northern Engineering. Included in this drainage certification submittal are the following: Attachment 1 - City of Fort Collins Overall Site and Drainage Certification Form. Attachment 2 - City of Fort Collins During Construction Inspection Checklist and photographs provided by contractor. Attachment 3 - As-constructed detention pond, rain garden, and LID calculations. Attachment 4 - As-constructed record drawings for Grading and Storm Drain Plan and Profile Sheets. Based on the calculations shown in Attachment 3, the as-built detention pond and rain garden volumes are in Table 1. The as-built detention pond within the parking lot will restrict the flows from the site. LID treatment is provided by a rain garden, roof top planters, and landscape buffers per LID Conformance Report dated August 28, 2018 (included as part of Attachment 3). Table 1: Pond Record Volumes Pond Design Water Vol. As-built Water Vol. (ft3) Parking Lot Detention 685 ft3 775 ft3 Garage Rain Garden 130 ft3 207 ft3 We have concluded, based on the attached information and personal site inspection, that the drainage features for the project site have been constructed in substantial compliance with the above referenced Final Utility Plans, with the following exceptions: FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com • Item I.B.3.a: The approved design drawings called for detention to be provided within the inundation of the eastern side of the underground parking structure. Therefore, the driveway access locations will act as the spillway for this pond. • Item I.B.3.b: The approved design drawings called for detention to be provided within the inundation of the eastern side of the underground parking structure. The driveway access locations will act as the spillway for this pond. Therefore, the width of the spillway is the width of the driveway access locations. • Item III.A.2: The Front Storm Drain Line from Drain Basin 1-1 to Drain Basin 1-2, shown on the utility plan (Sheet C300), was constructed with a slope flowing less than 0.40%. (A slope of 0.34% was constructed.) We have re-analyzed this storm line and compared to the hydraulic grade line. As shown in Figure 1, there is minimal change to the 100-year HGL. • Item III.A.2: The Front Storm Drain Line from Drain Basin 1-4 to Drain Basin 1-5, shown on the utility plan (Sheet C300), was constructed with a slope flowing less than 0.40%. (A slope of 0.08% was constructed.) We have re-analyzed this storm line and compared to the hydraulic grade line. As shown in Figure 1 there is minimal change to the 100-year HGL. • Item III.B.2: Northern Engineering did not observe construction. Northern Engineering was unable to verify the clearances between the storm drain pipes and any crossing utilities. • Item III.B.3: Northern Engineering did not observe construction. Northern Engineering was unable to verify the joint types and construction methods used for the storm drain pipes. Figure 1:Front Storm Drain Hydraulic Profile Drain Line from Basin 1-4 to 1-5 Drain Line from Basin 1-1 to 1-2 FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com • Item VII.A.6: According to the contractor, the underdrains were not wrapped in geotextile fabric. The approved design drawings did not require the underdrains to be wrapped with a geotextile fabric. However, the entire rain garden was wrapped with an impermeable liner per the approved design drawings. • Item XIII.A.1: At the time of Northern Engineering’s site investigation, construction debris was not removed throughout the project site. Please feel free to contact me with any questions you may have. NORTHERN ENGINEERING SERVICES, INC. Frederick S. Wegert, PE Project Engineer 10/29/18 FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com Attachment 1 8/16 Page 1 OVERALL SITE and DRAINAGE CERTIFICATION Commercial, Multi-Family and Subdivision Certification Form and Checklist Project Name: Date: Building Permit Numbers: (Commercial or multi-family) Per the requirement in Fort Collins Stormwater Criteria Manual (FCSCM) Volume 1, Section 6.11, please fill in all applicable items in this Certification Form for Commercial, Multi-Family and Overall Single Family sites. NOTE: several items must be verified during construction. A copy of the approved grading plan must be submitted with the as-built grading plan. (As-built elevations must be written in red next to the approved elevations.) •Use “Yes” for items completed as described. •Use “N/A” for items that are not applicable to the site being certified. •If any blanks are “No,” attach an explanation referencing the item number below. Attach an explanation or description of the as-built condition for any items listed or for anything not listed but shown on the approved construction plans. Provide an as-built redline or Mylar drawing with the following: I.Water Quality and Quantity Detention Basin Certification - FCSCM Vol.2, Ch.10 For multiple detention basins on a site, provide the following for each basin separately: A. Volume: As-built topographic verification is attached at 1-foot (or less) contour intervals and volume verification calculations for the water quality capture volume and the 100-year detention storage volume. 1. Detention basin topography was prepared by a professional land surveyor registered in the state of Colorado. 2.Both proposed and as-built contours are shown on the same plan sheet (dashed lines for proposed and solid lines for as-built). 3.All critical spot elevations as shown on the approved construction plans have been verified and the as-built elevations are shown on the plan sheet. 4.Stage-storage-discharge tables are provided on a separate document. 5.Verification that designed drain time is in compliance with Colorado Revised Statute § 37-92- 602(8) is attached and has been uploaded to the Statewide Compliance Portal (tinyurl.com/COCompliancePortal) for approval. Uploaded documents must include: a.The cover sheet from the approved drainage report b.The stamped certification page from the approved drainage report c.As-built topographic survey d.Stamped certification page from the Overall Site & Drainage Certification e.PDF output from the Stormwater Detention and Infiltration Design Data Speadsheet Maple Mixed Use October 17, 2018 B1700802 Yes Yes Yes Yes Yes Yes 8/16 Page 2 B.Water Quality and Quantity Detention Basin Grading: Attached is as-built verification that there is a minimum 2% positive fall into the concrete trickle pans or flow-line(s) from all areas in the bottom of the detention pond. If there is a “soft pan” in the flow-line, all areas still must meet the minimum 2% grade requirement. 1.Low Flow: Choose one of the following detention basin low flow options as applicable: a. Turf swale for low flow path in detention basin. There is a minimum 2% grade in the flow-line(s) of the detention basin. The flattest as-built grade is . b.Concrete pan for low flow in detention basin. There is a concrete pan installed that meets the grades as shown on the approved construction plans. (Show as-built spot elevations.) c.Soft pan for low flow in detention basin. •Verify and document the soft pan material gradation, trench width and depth - to be verified during construction by engineer. Picture documentation is preferred or engineer’s statement of visual inspection and compliance. (Choose one below.) o There is a soft pan with an underdrain installed that meets the design on the approved construction plans. (Show the underdrain grades, bedding material, geotextile, spot elevations, bends, cleanouts, etc.) o There is soft pan installed without an underdrain but there is a type A or B soil. The soil type must be documented by supplying verification from a registered professional geotechnical engineer. NOTE: Spot elevations are to be within 0.2 ft. +/-. 2. Side Slopes: The as-built side slopes of the detention basin have been calculated and are shown. Indicate the side slope with an arrow and a numerical value (e.g., 6.25:1). The maximum slope allowed is 4:1. Small areas of 3:1 may be acceptable, but slopes steeper than 3:1 must be stabilized or re- graded. Provide documentation if a variance was granted for steeper slopes during the design process. 3.Spillway Certification: The following items must be field verified: a.The location of the spillway is indicated on the as-built plan. b.The width of the spillway is indicated on the as-built plan. c.The elevation(s) of the spillway is shown on the as-built plan. d.A concrete ribbon defines the location and grade of the spillway. e.There is downstream scour protection in the spillway as per the construction plans. Indicate type: (riprap size “D50” gradation and bedding type, geotextile, buried riprap with inches of bury, etc.). f.There are no obstructions in the spillway, such as trees, bushes, sidewalks, landscape features, rocks, etc. Yes N/A N/A Yes Yes N/A Yes Yes Yes Yes Yes Yes Yes Concrete Driveway 8/16 Page 3 4.Outlet Structure Certification a.The orifice plate for the approved release rate is installed with the correct size and location of the orifice. b.The orifice plate for the water quality outlet is installed with the correct hole size, number of rows and columns of holes. c.The bottom hole on both the water quality and quantity outlets are at the bottom of the plate so no water ponds in front of the plate. d.The well screen is the correct material and is installed as shown on the construction plans. e.100-year overflow grate elevation is . (Elev. A on detail D-46) f.The top elevation of the water quality capture volume is . (Elev. B on detail D-46) g.Overflow grate is made of the correct material, has the correct bar spacing, is hinged at the top and bolted at the bottom. h.The bottom of the outlet box has no obstructions or misalignments that will cause it to retain runoff water and is sloped at 2% towards outlet. II.Channels/Swales - FCSCM Vol.1, Ch.7, Sect.3&4 A. Capacity: The as-built capacity of all the major channels and swales has been verified. They meet or exceed capacity requirements shown in the approved drainage study for this project. 1.All swales are located within the drainage easements as shown on the construction plans. 2.Longitudinal slopes and side-slopes (cross-sections) have been verified. Design criteria requires longitudinal slopes of 2% min. (on vegetated swales) and side-slopes no steeper than 4:1. If these criteria are not met, the certification engineer will write a justification and propose mitigation for each instance or have the issues corrected. If variances to these criteria have previously been approved and are shown on the construction plans, no justification is needed. 3.As-built spot elevations on channels/swales are shown that correspond to spot elevations shown on the approved construction plans. 4.All permanent erosion control measures are installed as shown on the approved construction plans (e.g., drop structures, riprap, TRMs, etc.). (Include pictures and verification of the materials used as part of this verification.) 5.All pans, curbs, storm pipes or other appurtenances appropriately tie into each other in the system. (Pictures at tie-in points suggested.) 6.The minimum freeboard is provided for all channels and swales as shown on the approved construction plans or as identified in the approved drainage study. (Show the freeboard provided on the cross-sections as on the construction plan set or attached as separate documentation.) 7.The low flow portion of all channels or swales is clear of obstructions. (No landscaping, trees, shrubs, sod, etc. infringe on the low flow portion of channels or swales.) Yes 4989.43 Yes Yes N/A N/A Yes N/A Yes N/A N/A N/A N/A Yes N/A N/A N/A 8/16 Page 4 III.Storm Pipes (aka storm drains) - FCSCM Vol.1, Ch.6, Sec. 4 A. Storm Drain Pipe Capacity: The as-built capacity of all pipes installed on this project has been verified and meets or exceeds the capacity requirements shown in the approved drainage study for this project. 1.All storm drain pipe sizes and materials have been verified and are in conformance with the approved construction plans. (Indicate on the plan and profile sheets that they have been verified.) Material and size substitutions must be approved prior to installation. If a pipe size or material was changed during construction, the certification engineer must attach the approval documents or supply them with this certification. Approval documents must include a calculation documenting the capacity equivalency (equal or greater) of the substituted size. 2.The longitudinal slope of the pipe is as shown on the approved construction plans. The acceptable minimum slope is 0.4%. All slopes flatter than the designed slope on the construction plans must be justified with capacity calculations on an attached sheet. 3.The as-built invert elevations have been verified and are shown on the plan and profile sheets of the approved construction plans. B.Storm Drain Pipe Installation Requirements: All pipes are installed in accordance with the approved construction plans. 1.The minimum cover requirements for all pipes have been met as shown on the approved construction plans. These will be called out in critical locations. 2.All encasements and clearances as specified on the approved construction plans have been met. 3.Any specific joint types or construction methods specified on the approved construction plans have been met. (List on a separate sheet and attach to this certification.) IV.Concrete Pans - FCSCM Vol.1, Ch.7, Sec.4.1.3.4 A. Construction/Installation: All concrete pans have been constructed in accordance with the approved construction plans. 1.The concrete pans are the correct size/width as shown on the approved construction plans. 2.The longitudinal slopes of the pans are as shown on the approved construction plans. The certification engineer must justify or mitigate longitudinal slopes less than the minimum of 0.4% unless a flatter slope was approved and is shown on the approved construction plans. Provide mitigation or justification by separate document. 3.The cross-section of the pan is as shown on the construction plans. (Specifically, the pan cross- section is “V” shaped and meets the side slope shown on the detail.) 4.The concrete pans are a minimum of 6 inches thick without reinforcement and a minimum of 4 inches thick with a minimum of 6X6-W14xW14 reinforcement per detail D20B and D20C. (Provide documentation of the reinforcement used if different than shown on the details or on the approved construction plans.) 5.The spot elevations shown on the concrete pan(s) have been verified and are shown on the as- built drawings. Yes Yes No Yes Yes Yes No No Yes Yes Yes Yes Yes Yes 8/16 Page 5 V. Storm Drain Inlets - FCSCM Vol.1, Ch.6, Sec. 3 A. Construction/Installation: All storm drain inlets have been constructed in accordance with the approved construction plans. 1.The size and type of inlets are consistent with the inlets shown on the approved construction plan. Indicate by writing “Verified” on each inlet on the plan sheet or list on a separate document the inlet number(s), type and size (length). If the inlet installed is other than the one on the approved construction plan detail sheet, provide the name and source of the detail with justification for equal or better capacity. 2.The size of the inlet opening is consistent with the approved detail. (Check height and width.) 3.The elevation of the grate (if applicable) is at the elevation shown on the street profile or as indicated by a spot elevation on the construction plans. 4.The as-built invert elevations of all pipes entering and leaving the inlet are shown on the plan and profile sheets within construction tolerance of 0.2 feet. If substantially different, provide justification and capacity calculations to show the capacity is not affected or propose mitigation. 5.The as-built size of the inlet box is as shown on the construction plans or an explanation or justification is attached. 6.All Type C, R, 13 and 16 inlet covers are stenciled or stamped with the following (or an equivalent) designation: NO DUMPING – DRAINS TO POUDRE RIVER. VI.Culverts - FCSCM Vol.2, Ch.9 A. Construction/Installation: All culverts have been constructed and/or installed in accordance with the approved construction plans. 1.All culvert sizes have been verified as indicated on the as-built construction plans as correct. 2.The culvert material type for all culverts installed is as on the approved construction plans and is indicated on the as-built plans. 3.The as-built invert “in and out” elevations have been verified and are indicated on the as-built construction plans. 4.The culvert headwalls or wing walls have been installed as shown on the approved construction plans. Headwalls or wing walls may be needed in the as-built conditions onsite if the slopes adjacent to the culvert are greater than 4:1. Please note areas needing stabilization in the certification narrative. An alternative to consider is a turf reinforcement mat (TRM). VII.Sub-Drains A. Construction/Installation: All sub-drains shown on the construction plans have been installed in accordance with those plans. Sub-drains installed with the sanitary sewer are to be verified on the sanitary sewer plan and profile sheets of the construction plans. (NOTE: Indicate any sub-drains installed after the plans were approved on the as-built plans.) 1.The size of the sub-drains are as approved on the construction plans and are indicated on the as- built plans. 2.The type of sub-drain, in particular the perforated and non-perforated sections of the drain, are as indicated on the approved construction plans. Yes Yes Yes Yes Yes Yes Yes N/A N/A N/A N/A N/A Yes Yes Yes 8/16 Page 6 3.The cover requirements per the construction plans are provided. 4.The cleanouts have been installed at the locations shown on the construction plans and are accessible for cleaning. (Cleanouts can be buried a maximum of 6 inches deep with their locations marked.) 5.The backfill materials for sub-drains are as shown on the approved construction plans. (This includes the type, depth and width.) 6.The geo-textile liner completely wraps the sub-drain and the permeable backfill material unless shown otherwise on the approved construction plans. (Sub-drain pipe wrapped in a sock filter material is accepted only if approved prior to installation.) VIII.Curb Cuts A. Construction: All curb cut openings are constructed in accordance with the approved construction plans. 1.The size (width) of the curb cut opening is as shown on the approved construction plans. 2.The curb cut openings tie into a downstream swale, pipe, or other appurtenances with a smooth transition and there no obstructions such as riprap or sod impeding the flow downstream of the curb cut. IX.Sidewalk Culverts & Chases A. Construction/Installation: All sidewalk culverts have been installed at the locations shown on the approved construction plans. 1.The size (width and length) of the culverts are as shown on the approved construction plans. 2.The cover plate is a minimum 5/8-inch galvanized plate bolted to a galvanized angle iron per the detail shown on the approved construction plans or per the City’s detail. 3.The sidewalk culvert invert “in and out” elevations have been verified and are indicated on the as-built plans. 4.The sidewalk culvert opening is as shown on the approved construction plans or per the City’s detail. 5.There is a smooth transition both on the inlet and outlet ends of the sidewalk culvert with no obstructions such as riprap or sod impeding the flow into or out of the sidewalk culvert. X. Site Grading A. Construction: All common open spaces have been graded in accordance with the approved construction plans. 1.The grading on all common open spaces bordering private lots has been verified as correct and the as-built rear lot corner elevations have been shown on the as-built plans. Yes Yes Yes No N/A N/A N/A N/A N/A N/A N/A N/A N/A Yes Yes 8/16 Page 7 2.The as-built contours for “overlot grading” are shown on the as-built construction plans for all common open spaces, tracts, outlots, etc. If not in compliance, please attach a narrative describing the situation for noncompliance and when it may be corrected. An escrow for overlot grading may be required. (NOTE: Residential Lot Grading Certification is a separate process from this Overall Site Certification. It is understood that residential lots will be brought to final grade once the foundation is backfilled so they may be lower than the plan shows at this Overall Site Certification stage.) 3.All turf reinforcement mats (TRMs) have been installed as shown on the approved construction plans and the slopes are stabilized. XI.Riprap - FCSCM Vol.1, Ch.7, Sec.4.4.4.3 A. Construction: All riprap has been installed in the locations and sizes indicated on the approved construction plans. XII.Permanent Erosion Control Fabric - FCSCM Vol.1, Ch.7 A. Construction: All fabric has been installed in the locations and sizes indicated on the approved construction plans. 1.All fabric was installed per the details on the approved construction plans. XIII.Post-Construction Site Cleanup - FCSCM Vol.3, Ch.7 A. Construction: All construction debris and obstructions of any kind have been removed from drainage paths. 1.All construction debris has been removed except in staging area(s). 2.All ruts have been smoothed out in all construction areas. 3.All areas needing reseeding have been identified and future stabilization goals have been coordinated with the Erosion Control Inspector and in accordance with FCSCM Vol.2 Chapter 12. Note the area needing stabilization in the narrative. XIV.Certification of Other Permanent BMPs - FCSCM Vol.2, Ch.8, Sec.2 & FCSCM Vol.2, Ch.12 A.The construction of channel drop structures is in accordance with the approved plan both in location, horizontal dimensions and cross-section. XV.Certification of LID and Water Quality Facilities - FCSCM Vol.3, Ch.4 A.Attached are the During Construction Inspection Checklist for Low Impact Development (LID) and other items to be verified during construction, along with pictures and other required documentation. N/A Yes Yes N/A N/A N/A N/A No No Yes Yes 8/16 Page 8 XVI. Certification and Erosion Control Measures A. All temporary erosion control measures shall be removed upon stabilization. If at the time of preparing this certification there are any erosion control measures still remaining on the site, please note them in the narrative and verify that they need to remain at this time. If in doubt as to the need for any control measure, please consult with the Erosion Control Inspector at 970-221-6700. XVII.Statement of Compliance A. This certification is signed and stamped. By signing this form, the engineer(s) attests that he/she has visited and observed the site, and to the best of his/her knowledge, the as-built conditions of the drainage facilities are as described in the above form and in the enclosed as-built plans. B.Failure to properly disclose all known information could result in the rejection of this certification and prevent the release of any and all Stormwater Utility permit holds on Building Permits and/or Certificates of Occupancy within this development. XVIII.Signature and Stamp by a Colorado-Registered Professional Engineer Engineer’s contact information: Name: Email: Phone: Company: Address: PE Stamp Frederick S. Wegert fred@northernengineering.com (970) 568-5408 Northern Engineering 301 N. Howes Street, Suite 100 Fort Collins, Colorado 80521 10/17/18 FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com Attachment 2 FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com Attachment 3 Project: Date: Outlet Elevation:4988.96 685 ft3 Grate Elevation:4988.96 Crest of Pond Elev.:4989.45 4989.43 Maximum Elevation Minimum Elevation cu. ft.acre ft cu. ft.acre ft 4988.96 N/A 0.0 0 0.0 0.00 0.0 0.00 4989.0 4989.0 8.3 0.0 0.2 0.00 0.2 0.00 4989.2 4989.0 659.7 0.2 66.8 0.00 67.0 0.00 4989.4 4989.2 4,145.0 0.2 480.5 0.01 547.4 0.01 4989.45 4989.4 4,945.3 0.1 227.3 0.01 774.7 0.02 As-Built Parking Lot Pond Stage Storage Curve Contour Contour Surface Area (ft2) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 574-007 Fort Collins, Colorado F. Wegert Parking Lot Elev at Design Volume: Maple Mixed Use 10/17/2018 Pond Outlet and Volume Data Design Volume: Project Number: Project Location: Calculations By: Pond No.: 10/17/2018 10:45 AM D:\Projects\574-007\Drainage\Detention\ 574-007_AB_Parking Lot_Stage-Storage.xlsx\Pond Project: Date: Bottom Elevation:4988.54 130 ft3 Crest of Pond Elev.:4990.11 4989.58 Maximum Elevation Minimum Elevation cu. ft.acre ft cu. ft.acre ft 4988.54 N/A 0.0 0 0.0 0.00 0.0 0.00 4988.7 4988.5 130.0 0.2 11.0 0.00 11.0 0.00 4989.0 4988.7 135.0 0.3 38.4 0.00 49.5 0.00 4989.5 4989.0 141.1 0.5 69.0 0.00 118.5 0.00 4990.0 4989.5 147.2 0.5 72.1 0.00 190.6 0.00 4990.1 4990.0 148.5 0.1 16.3 0.00 206.8 0.00 Project Number: Project Location: Calculations By: Pond No.: As-Built Garage Rain Garden Stage Storage Curve Contour Contour Surface Area (ft2) Depth Incremental Volume Cummalitive Volume Pond Stage Storage Curve 574-007 Fort Collins, Colorado F. Wegert Rain Garden Elev at Design Volume: Maple Mixed Use 10/9/2018 Pond Outlet and Volume Data Design Volume: 10/17/2018 11:39 AM D:\Projects\574-007\Drainage\Detention\ 574-007_AB_Rain Garden_Stage-Storage.xlsx\Pond Project Number:Project: Project Location: Calculations By:Date: Pond No.: Description Area (ft2)Depth of Box (ft) Depth of Biomaterial (ft) As-Built Volume (ft3) Required Volume (ft3) Northeast Planter Box 58 3 2.21 46 North Mid-East Planter Box 53 3 2.21 42 South Mid-East Planter Box 75 3 2.21 59 Southeast Planter Box 158 3 2.21 125 273 291 Northwest Planter Box 58 3 2.17 49 North Mid-West Planter Box 53 3 2.17 45 South Mid-West Planter Box 75 3 2.17 62 Southwest Planter Box 158 3 2.17 132 287 267 560 558 Asbuilt Buffer Area (ft2) Asbuilt Run- On Area (ft2) Total Asbuilt Area (ft2) Required Area (ft2) 1,074 0 1,074 1,074 1,014 443 1,457 1,443 LID Volumes & Areas 574-007 Fort Collins, CO Maple Mixed Use 10/17/2018F. Wegert Planter Boxes & Buffers Planter Box Volume Data Landscape Buffer Areas Description South Landscape Buffers West Landscape Buffers Total Volume Eastside Total Volume Westside Total Volume of Planter Boxes LID Conformance Report Date: August 28, 2018 Project: Maple Mixed Use Project No. 574-007 Fort Collins, Colorado Attn: Stormwater Staff City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 Stormwater Staff: This letter serves to document conformance of the above referenced project with City of Fort Collins Low Impact Development (LID) requirements. In particular, the project is meeting Section 3.1 of the Fort Collins Stormwater Amendments to the Urban Drainage and Flood Control District Criteria Manual, including Section3.1 (a)(1) requiring that no less than 50% of any newly added impervious area be treated using one or more LID techniques and Section 3.1(a)(2) and requiring that no less than 25% of all new paving use a permeable pavement technology that is considered an LID technique OR requiring that no less than 75% of any newly added impervious area be treated using one or more LID techniques with no minimum requirement for permeable pavement. Section 3.1(a)(1) The entire project site has an impervious area of 25,814 sf. This results in a minimum required LID treatment area of 12,907 sf. The project is treating 17,079 sf of the project area using bio-retention planters that will be located in the second-floor courtyard and is also treating 3,892 sf of the project using a raingarden located within the garage. Finally, the project is treating an additional 2,517 sf of additional area using Landscape Buffers that will have an engineered soil section to promote infiltration. The total project area treated by LID techniques is 23,488 sf, which is 82.40% of the total project area. Section 3.1(a)(2) The project is not proposing any areas of exposed impervious paving for parking, removing the requirement for permeable pavement to be used on this project. An exhibit has been provided to illustrate the topics outlined. Please feel free to contact me if you have any questions. Sincerely, Andrew Reese Nicholas W. Haws, PE Project Engineer Project Manager. FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com Attachment 4 TT W W W CS VAULT ELEC FO VAULT ELEC S S CSW CONTROL IRR C VAULT ELEC W E E G G G G G CTV CTV CTV CTV CTV EEEEEE E W G G G G G G G G G G W W WW W W W W W W W W W W W W W E E E E E E E E E E E E E CT V CT V CT V CT V CT V CT V CT V CT V CT V CT V CTV IRR SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS SS ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST ST SS SS SS SS SS SS SS SS SS SS WASHINGTON PARK, LLC 301 N. HOWES STREET JESS L & DICK L. GRIES 312 N. MELDRUM STREET CITY OF FORT COLLINS 300 LAPORTE AVENUE WASHINGTON PARK, LLC 301 N. HOWES STREET WASHINGTON PARK, LLC 301 N. HOWES STREET JAMES E. & CAROL S. BURRILL 305 MAPLE STREET SS S SS S SS S W W W W W W W W TFTF UP UP UP UP MAPLE STREET (100' ROW) ME L D R U M S T R E E T (1 0 0 ' R O W ) AL L E Y (2 0 ' R O W ) SAN MH RIM=4991.09 INV IN=4981.10 (S) 6" CIP INV IN=4979.99 (N) 6" CIP INV IN=4979.54 (W) 12" CIP INV OUT=4979.54 (E) APPROXIMATE LOCATION OF EXISTING GAS LINE APPROXIMATE LOCATION OF EXISTING 8" WATER LINE EXISTING 3 4" WATERSERVICE TO BE REUSED FOR IRRIGATION EXISTING SANITARY SERVICE TO BE REUSED EXISTING WATER SERVICE (TYP.) EXISTING WATER SERVICE (TYP.) APPROXIMATE LOCATION OF EXISTING 12" SANITARY SEWER APPROXIMATE LOCATION OF EXISTING 16" WATER LINE EXISTING SANITARY SERVICE TO BE REPLACED WITH 6" PVC SERVICE APPROXIMATE LOCATION OF EXISTING ELECTRIC LINE TO BE RELOCATED OR ABANDONED AS NEEDED APPROXIMATE LOCATION OF EXISTING GAS LINE EXISTING ELECTRIC FACILITIES EXISTING ELECTRIC LINE EXISTING CABLE LINE PROPOSED ELECTRIC TRANSFORMER APPROXIMATE LOCATION OF EXISTING 6" SANITARY SEWER PROPOSED 6" FIRE SERVICE EXISTING 3 4" WATER SERVICETO BE REUSED FOR COMMERCIAL PROPOSED 3" RESIDENTIAL WATER SERVICE APPROXIMATE LOCATION OF EXISTING 15" STORM SEWER STORM DRAIN A SEE SHEET C301 EXISTING WATER SERVICE FOR ADJACENT PROPERTY EXISTING SANITARY SERVICE FOR ADJACENT PROPERTY APPROXIMATE LOCATION OF EXISTING CABLE LINE TO BE RELOCATED OR ABANDONED AS NEEDED PROPOSED SUBDRAIN PROPOSED SUBDRAIN PROPOSED CATCH BASIN (TYP.) N:132439.86 E:193485.22 N:132440.80 E:193295.32 N:132590.80 E:193296.01 N:132589.85 E:193485.97 SAN MH RIM=4989.55 INV IN=4978.61 (S) 6" CIP INV IN=4977.93 (W) INV OUT=4977.85 (E) LANDSCAPE BUFFER (TYP.) LANDSCAPE BUFFER (TYP.) PROPOSED AREA INLET PROPOSED AREA INLET PUBLIC STORM DRAIN PRIVATE STORM DRAIN BASIN 1-3 (w/ SOLID LID) INV. IN=4987.79 (N) INV. OUT=4987.79 (E) FG=4990.63 BASIN 1-5 INV. IN=4988.20 (N) INV. OUT=4988.20 (S) FG=4990.00 BASIN 1-6 INV. IN=4988.37 (N) INV. OUT=4988.37 (S) FG=4990.00 BASIN 1-4 INV. IN=4988.00 (N) INV. OUT=4988.00 (S) FG=4990.00 BASIN 1-7 INV. OUT=4988.47 (S) FG=4990.00 BASIN 1-1 INV. IN=4987.16 (W) INV. OUT=4987.16 (E) FG=4989.41 BASIN 1-2 INV. IN=4987.52 (W) INV. OUT=4987.52 (E) FG=4989.56 BASIN 1 INV. IN=4986.93 (W) INV. OUT=4986.93 (E) FG=4988.89 SD CONNECTION INV. IN=4985.90 (W) INV. IN=4985.52 (N) INV. OUT=4985.52 (S) FG=4988.80 18.67 LF 6" HDPE @ 5.55% 43.91 LF 6" HDPE @ 0.50%73.17 LF 6" HDPE @ 0.50%52.27 LF 6" HDPE @ 0.50% 41 . 0 8 L F 6 " H D P E @ 0 . 5 0 % 41 . 4 2 L F 6 " H D P E @ 0 . 5 0 % 33 . 5 0 L F 6 " H D P E @ 0 . 5 0 % 19.69 LF 6" HDPE @ 0.50% DR A I N A G E EA S E M E N T 5' UTILITY EASEMENT 9' UTILITY EASEMENT 9' UTILITY EASEMENT D D H2O V.P.W F F C.O. C.O. SD SD SD SD SD SD SD SD SD SD SD Sheet Of 15 Sheets MA P L E M I X E D U S E 30 1 N o r t h H o w e s S t r e e t , S u i t e 1 0 0 Fo r t C o l l i n s , C o l o r a d o 8 0 5 2 1 E N G I N E E R N G I E H T R O N R N PH O N E : 9 7 0 . 2 2 1 . 4 1 5 8 ww w . n o r t h e r n e n g i n e e r i n g . c o m 11.10.16 NORTH ( IN FEET ) 0 1 INCH = 20 FEET 20 20 40 60 C300 UT I L I T Y P L A N NOTES: 1. THE SIZE, TYPE AND LOCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO VERIFY THE EXISTENCE OF ALL UNDERGROUND UTILITIES IN THE AREA OF THE WORK. BEFORE COMMENCING NEW CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR ALL UNKNOWN UNDERGROUND UTILITIES. 2. ALL WATER AND SEWER CONSTRUCTION SHALL BE PER THE CITY OF FORT COLLINS STANDARD CONSTRUCTION SPECIFICATIONS LATEST EDITION. 3. ALL WATER FITTINGS AND VALVES ARE ONLY GRAPHICALLY REPRESENTED AND ARE NOT TO SCALE. 4. UTILITY SERVICES ARE SHOWN IN A SCHEMATIC FASHION ONLY. EXACT LOCATIONS SHALL BE PER THE REQUIREMENTS OF THE RESPECTIVE UTILITY PROVIDERS, AND ARE SUBJECT TO CHANGE IN THE FIELD. 5. MAINTAIN 10' HORIZONTAL AND 18" VERTICAL MINIMUM SEPARATION BETWEEN ALL SANITARY SEWER MAINS, WATER MAINS, AND SERVICES. 6. REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS, UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION. 7. LIMITS OF STREET CUT ARE APPROXIMATE. FINAL LIMITS ARE TO BE DETERMINED IN THE FIELD BY THE CITY ENGINEERING INSPECTOR. ALL REPAIRS TO BE IN ACCORDANCE WITH CITY STREET REPAIR STANDARDS. 8. ANY DAMAGED CURB, GUTTER AND SIDEWALK EXISTING PRIOR TO CONSTRUCTION, AS WELL AS STREETS, SIDEWALKS, CURBS AND GUTTERS, DESTROYED, DAMAGED OR REMOVED DUE TO CONSTRUCTION OF THIS PROJECT, SHALL BE REPLACED OR RESTORED TO CITY OR FORT COLLINS STANDARDS AT THE DEVELOPER'S EXPENSE PRIOR TO THE ACCEPTANCE OF COMPLETED IMPROVEMENTS AND/OR PRIOR TO THE ISSUANCE OF THE FIRST CERTIFICATE OF OCCUPANCY. 9. REFER TO PLUMBING PLANS FOR ALL WATER SERVICE AND SANITARY SEWER SERVICE LOCATIONS. IF CONFLICT OCCURS, BOTH THE PLUMBING ENGINEER AND CIVIL ENGINEER SHALL BE CONTACTED PRIOR TO INSTALLATION OR ORDERING OF MATERIALS. 10. ALL SANITARY SEWER SERVICE CONNECTION INVERTS AND LOCATIONS BASED ON BEST AVAILABLE DATA. CONTRACTOR TO VERIFY LOCATION PRIOR TO CONSTRUCTION AND NOTIFY ENGINEER OF ANY DISCREPANCIES. 11. PIPE LENGTHS ARE CALCULATED FROM THE CENTER OF MANHOLES AND INLET BOX STRUCTURES. SPECIFIED LENGTH OF PIPE INCLUDES THE LAYING LENGTH OF FLARED END SECTIONS. 12. ALL RCP SHALL BE CLASS III OR GREATER. PIPE MATERIAL, BEDDING, AND INSTALLATION WITHIN PUBLIC RIGHTS-OF-WAY SHALL BE GOVERNED BY THE CITY OF FORT COLLINS. ALTERNATES (SUCH AS ADS N-12 OR HP SANITITE) OUTSIDE OF THE R.O.W. SHALL BE APPROVED IN ADVANCE BY THE ENGINEER. ALL JOINTS SHALL BE 'WATERTIGHT' USING APPROPRIATE GASKETS OR JOINT WRAPS (PER ASTM C443/C877 FOR RCP AND PER ASTM F477 / D3212 FOR PLASTIC PIPE). STORM DRAINS SHOWN ON THIS DRAWING AS POLYVINYL CHLORIDE (PVC) SHALL BE SDR-35 OR APPROVED EQUAL. 13. CONTRACTOR SHALL BE RESPONSIBLE FOR ANY NECESSARY FIELD LOCATES AND POTHOLING OF SUBSURFACE UTILITIES. ENGINEER AND CITY SHALL BE NOTIFIED OF ANY POTENTIAL CONFLICTS. 14. CONTRACTOR SHALL COORDINATE ANY NECESSARY TELEPHONE, CABLE, FIBER, GAS, AND ELECTRIC LOWERINGS (OR RE-ROUTING) WITH THE RESPECTIVE UTILITY PROVIDERS TO FACILITATE THE INSTALLATION OF THE PROPOSED STORM DRAIN, METER VAULT, AND UTILITY SERVICES. 15. A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION WILL BE REQUIRED PRIOR TO ANY WORK OCCURRING WITHIN THE FLOODWAY. 16. SEE THE FLOODPLAIN EXHIBIT (SHEET C800) FOR ADDITIONAL INFORMATION REGARDING WORK WITHIN THE FLOODPLAIN AND FLOODWAY. EXISTING WATER MAIN LEGEND: W G T E EXISTING STORM SEWER EXISTING ELECTRIC EXISTING TELEPHONE EXISTING GAS SPROPOSED SEWER SERVICE EXISTING SANITARY SEWER SS PROPOSED CURB & GUTTER PROPOSED WATER SERVICE & CURB STOP PROPOSED FIRE HYDRANT EXISTING FIRE HYDRANT EASEMENT LINE PROPERTY BOUNDARY EXISTING LOTLINE APPROXIMATE GAS METER LOCATION GM W PROPOSED WATER MAIN PROPOSED SANITARY SEWER PROPOSED STORM SEWER APPROXIMATE ELECTRIC METER LOCATION EM ST SDPROPOSED SUBDRAIN EXISTING PAVEMENT TO BE REMOVED PROPOSED FIRE DEPARTMENT CONNECTION FDC GPROPOSED GAS EPROPOSED ELECTRIC CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow.before you dig.Call R RECO R D D R A W I N G D D H2 O V. P . WFF C. O . SD SD SD TT VA U L T EL E C FO VA U L T EL E C S C VA U L T EL E C G G G G G CT V CT V CT V CT V CT V E E E E E E E W W W W W W E E E EEEEEEEE E E CTV CTV CTV CTV CTV CTV CTV CTV CTV CTV CT V SS SS SS SS SS SS SS ST ST ST ST ST ST ST ST ST SS S TFTF UP UP WASHINGTON PARK, LLC 301 N. HOWES STREET WASHINGTON PARK, LLC 301 N. HOWES STREET WASHINGTON PARK, LLC 301 N. HOWES STREET STMH A1 (FLAT TOP) STA 10+00.00 N: 132396.93 E: 193487.14 INLET A3 STA 11+32.97 N: 132500.81 E: 193458.40 15"x6" INSERTA TEE STA 10+46.91 N: 132443.85 E: 193487.37 46.91 LF 15" RCP @ 0.40% 29.24 LF 15" RCP @ 0.40% 56.82 LF 15" RCP @ 0.40% MA P L E S T R E E T (1 0 0 ' R O W ) ALLEY (20' ROW) EXISTING 15" STORM EXISTING 16" WATER APPROXIMATE LOCATION OF EXISTING GAS LINE APPROXIMATE LOCATION OF EXISTING ELECTRIC LINE APPROXIMATE LOCATION OF EXISTING CABLE LINE PROPOSED SUBDRAIN SEE SHEET C300 PROPOSED TRANSFORMERORIFICE PLATE PRIVATE STORM DRAIN 54.26 LF 15" RCP @ 0.40% INLET A4 STA 11+87.23 N: 132555.07 E: 193458.67 STMH A2 (FLAT TOP) STA 11+03.73 N: 132500.66 E: 193487.63 PUBLIC STORM DRAIN DRAINAGE EASEMENT 4975 4980 4985 4990 4995 5000 5005 4975 4980 4985 4990 4995 5000 5005 9+50 10+00 11+00 12+00 PROPOSED GROUND EXISTING GROUND STA.=10+07.03 TOP= 4983.8± EX. 16" WATER LINE (ELEVATIONS NOT VERIFIED) STA.=10+15.39 INV.= 4984.8± EX. GAS LINE (ELEVATIONS NOT VERIFIED) 15 " x 6 " I N S E R T A T E E ST A 1 0 + 4 6 . 9 1 IN V . 4 9 8 5 . 9 0 ( W ) IN V . 4 9 8 5 . 5 2 ( N ) IN V . 4 9 8 5 . 5 2 ( S ) ST M H A 1 ( F L A T T O P ) ST A 1 0 + 0 0 . 0 0 RI M 4 9 8 9 . 1 ± IN V . I N 4 9 8 5 . 3 4 ( N ) IN V . I N 4 9 8 2 . 7 1 ( W ) IN V . O U T 4 9 8 2 . 7 1 ( E ) CONTRACTOR TO VERIFY LOCATION PRIOR TO CONSTRUCTION. EL E C T R I C ST A . = 1 0 + 2 5 . 5 9 CA B L E ST A . = 1 0 + 2 7 . 8 7 18" MIN. 6" MIN. IN L E T A 3 ST A 1 1 + 3 2 . 9 7 FL . E L 4 9 8 8 . 9 ± IN V . I N 4 9 8 5 . 8 7 ( N ) IN V . O U T 4 9 8 5 . 8 7 ( E ) IN L E T A 4 ST A 1 1 + 8 7 . 2 3 FL . E L 4 9 8 8 . 9 ± IN V . I N 4 9 8 6 . 0 8 ( N E ) IN V . O U T 4 9 8 6 . 0 8 ( S ) ST M H A 2 ( F L A T T O P ) ST A 1 1 + 0 3 . 7 3 RI M 4 9 8 9 . 1 ± IN V . I N 4 9 8 5 . 7 5 ( W ) IN V . O U T 4 9 8 5 . 7 5 ( S ) ORIFICE PLATE PUBLIC STORM DRAIN PRIVATE STORM DRAIN 29.24 LF 15" RCP @ 0.40% 56.82 LF 15" RCP @ 0.40% 46.91 LF 15" RCP @ 0.40% 54.26 LF 15" RCP @ 0.40% 100-YR HGL Sheet Of 15 Sheets MA P L E M I X E D U S E 30 1 N o r t h H o w e s S t r e e t , S u i t e 1 0 0 Fo r t C o l l i n s , C o l o r a d o 8 0 5 2 1 E N G I N E E R N G I E H T R O N R N PH O N E : 9 7 0 . 2 2 1 . 4 1 5 8 ww w . n o r t h e r n e n g i n e e r i n g . c o m 11.10.16 NORTH ( IN FEET ) 0 1 INCH = 20 FEET 20 20 40 60 C301 PL A N & P R O F I L E ST O R M D R A I N A PROFILE SCALE: EXISTING WATER MAIN PROPOSED WATER MAIN PROPOSED STORM SEWER LEGEND: NOTES: W EXISTING SANITARY SEWER SS PROPOSED STORM INLET PROPOSED CURB & GUTTER PROPOSED SANITARY SEWER PROPOSED FIRE HYDRANT EXISTING FIRE HYDRANT PROPOSED LOT LINE EXISTING EASEMENT LINE PROJECT BOUNDARY EXISTING RIGHT OF WAY EXISTING STORM SEWER PROPOSED EASEMENT LINE 1. THE SIZE, TYPE AND LOCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO VERIFY THE EXISTENCE OF ALL UNDERGROUND UTILITIES IN THE AREA OF THE WORK. BEFORE COMMENCING NEW CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR ALL UNKNOWN UNDERGROUND UTILITIES. 2. MAINTAIN 10' HORIZONTAL AND 18" VERTICAL MINIMUM SEPARATION BETWEEN ALL STORM DRAINS, SANITARY SEWER MAINS, WATER MAINS, AND SERVICES. 3. PIPE LENGTHS ARE CALCULATED FROM THE CENTER OF MANHOLES AND INLET BOX STRUCTURES. SPECIFIED LENGTH OF PIPE INCLUDES THE LAYING LENGTH OF FLARED END SECTIONS. 4. ALL RCP SHALL BE CLASS III OR GREATER. PIPE MATERIAL, BEDDING, AND INSTALLATION WITHIN PUBLIC RIGHTS-OF-WAY SHALL BE GOVERNED BY THE CITY OF FORT COLLINS. ALTERNATES (SUCH AS ADS N-12 OR HP SANITITE) OUTSIDE OF THE R.O.W. SHALL BE APPROVED IN ADVANCE BY THE ENGINEER. ALL JOINTS SHALL BE 'WATERTIGHT' USING APPROPRIATE GASKETS OR JOINT WRAPS (PER ASTM C443 FOR RCP AND PER ASTM F477 / D3212 FOR PLASTIC PIPE). 5. CONTRACTOR SHALL BE RESPONSIBLE FOR ANY NECESSARY FIELD LOCATES AND POTHOLING OF SUBSURFACE UTILITIES. ENGINEER AND CITY SHALL BE NOTIFIED OF ANY POTENTIAL CONFLICTS. 6. CONTRACTOR SHALL VERIFY MINIMUM 18" SEPARATION BETWEEN EXISTING WATER LINE AND PROPOSED STORM DRAIN PIPE. IF MINIMUM SEPARATION REQUIREMENT BETWEEN UTILITIES IS NOT MET, CONTRACTOR SHALL ENCASE WATER LINE PER CITY OF FORT COLLINS REQUIREMENTS. 7. ROOF DRAIN CONNECTIONS TO STORM DRAIN SHALL BE MADE USING INSERTA-TEE OR APPROVED EQUAL. REFER TO PLUMBING PLANS FOR ADDITIONAL INFORMATION. 8. A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION WILL BE REQUIRED PRIOR TO ANY WORK OCCURRING WITHIN THE FLOODWAY. 9. SEE THE FLOODPLAIN EXHIBIT (SHEET C800) FOR ADDITIONAL INFORMATION REGARDING WORK WITHIN THE FLOODPLAIN AND FLOODWAY. PROPOSED RIGHT OF WAY PROPOSED NON-POTABLE IRRIGATION NP CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow.before you dig.Call R STORM DRAIN A RECO R D D R A W I N G D D SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD CONTROL IRR / / / / / / / / TFTF UP UP UP UP MAPLE STREET (100' ROW) ME L D R U M S T R E E T (1 0 0 ' R O W ) AL L E Y (E X I S T I N G 2 0 ' R O W ) 1.6 % 1.3% 1.1% 1.1% 1.3% 2.9% 1.6 % 2.0% 3.2% 1.8% 4. 3 % 1.5% 6.3% 1.0% 12 . 2 % 12 . 8 % 14 . 0 % 1.7 % 1.1% 2.0% 2.0% 2.0% 2. 0 % 3.1% 3.2% 1.2% 1.1% 1.3% 1.1% 1.7 % DETENTION AREA 100-YR WSEL = 4989.33 89 90 89.2 89.489.6 89.8 89 90 89.2 89 . 4 89 . 6 89 . 8 89 . 2 89 . 2 89 . 4 89 . 4 CITY-REGULATED OLD TOWN 100-YR FLOODWAY OLD TOWN FLOODPLAIN OLD TOWN FLOODPLAIN 1 - 6" RISER 2 - 6" RISERS AREA DRAIN AREA DRAIN AREA DRAIN AREA DRAIN AREA DRAIN AREA DRAIN AREA DRAIN CITY REGULATED OLD TOWN 100-YR FLOOD PLAIN BOUNDARY LANDSCAPE BUFFER LANDSCAPE BUFFER LANDSCAPE BUFFERLANDSCAPE BUFFER LANDSCAPE BUFFER LANDSCAPE BUFFER LANDSCAPE BUFFER STORM DRAIN A SEE SHEET C301 PROPOSED AREA INLET PROPOSED AREA INLET w/ ORIFICE PLATE MATCH EXISTING MATCH EXISTING SIDEWALK MATCH EXISTING CURB & GUTTER MATCH EXISTING CURB & GUTTER MATCH EXISTING SIDEWALK MATCH EXISTING SIDEWALK MATCH EXISTING CURB & GUTTER MATCH EXISTING CURB & GUTTER MATCH EXISTING SIDEWALK DRAIN A G E E A S E M E N T DRA I N A G E E A S E M E N T PROPOSED 18" OUTFALL VERTICAL CURB & GUTTER PROPOSED 18" OUTFALL VERTICAL CURB & GUTTER PROPOSED 30" VERTICAL CURB & GUTTER PROPOSED 30" VERTICAL CURB & GUTTER 90 . 6 90 . 8 90.2 90.4 90.6 90 . 6 90 . 8 90 89.8 90.2 90.4 90.6 90.8 90.8 90 89. 689. 8 90. 2 89899089.2 89.289.489.689.890.2 90 . 4 90 . 6 FFE=91.00 FFE=91.00 FFE=91.00 FFE=91.00 FFE=91.00 88. 5 7 (89 . 1 8 ) 90.0 2 89.9 2 89.9 1 89.8 7 89. 8 0 89. 7 5 88. 5 1 (89.1 1 )90.5 0 90.4 0 91.00 90.8 2 91.00 91.0 0 90.9 9 90.8 7 90.50 91.0 0 89.5 2 88.9 1 90.22 90.1 5 90.15 89.3 3 89.42 89.3 4 89.5589.1 0 90.2 2 89.8 1 89.0 6 90.97 91.00 90.7 5 90.8 2 90.2 7 FFE=91.00 (89. 2 5 ) (89. 2 0 ) (88. 7 5 ) 88.8 9 90 . 6 9 90.9 6 89.3 8 89. 3 8 90.7 3 89.1 6 89.25 89.5 5 89. 5 5 89 . 4 2 89.2 8 89.4 0 89.5 2 89. 6 6 88.68 88.96 89.1 0 90.05 (89. 7 4 ) 89.82 (90. 0 2 ) 88. 4 2 88.72 88.8 9 (88 . 4 1 ) (90 . 3 6 ) 90.5 9 (90 . 5 9 ) (90.59) 90.82 91.00 90.8 5 90.9 7 90.8 0 90.27 91.0 0 90.4 4 89.3 3 90.78 90.2 2 89. 7 0 90.0 4 (88. 9 4 ) (88. 9 6 ) (89.0 3 ) 89.14 89.3 4 88.94 (90 . 0 1 ) (90 . 9 9 ) (89 . 2 1 ) (91 . 0 0 ) (90.9 0 ) 90.9 2 90.8 1 90.8 9 90.7 9 90.7 8 90.8 8 90.7 0 90.4 8 90.5 2 90.7 4 90.8 4 91.0 0 90. 1 7 90.17 90.1 7 90.1 3 90.87 90.50 (9 0 . 0 7 ) (90 . 1 2 ) (90.05)(90 . 0 8 ) (90 . 0 7 ) (89. 7 9 ) (89. 6 8 ) 89.2 6 90 . 5 0 90.3 3 90.33 (89 . 8 5 ) (89 . 8 4 ) (89 . 9 3 ) 90.23 88.8 9 89.4 1 89.5 6 90.00 90.00 90.00 90.00 90.9 7 (88 . 9 8 ) 90.1 5 89.5 0 89. 6 5 90.1 6 89. 9 3 90.4 7 89. 8 5 89.7 8 89. 8 1 89. 8 1 89. 8 1 89. 9 4 89. 7 2 89. 4 5 89. 2 2 89. 4 8 89. 5 0 89. 1 7 89. 1 4 89. 4 6 89.2 0 90.33 (90 . 8 9 ) (90 . 5 4 ) (90 . 5 7 ) (90 . 0 8 ) (89 . 9 2 ) (89 . 7 6 ) (89 . 6 5 ) (89 . 4 9 ) (89 . 3 8 ) (89 . 2 7 ) (90 . 8 8 ) 89.7 5 90.7 2 90.8 3 90.8 4 90.7 4 90.9 8 90.9 2 90.9 2 FFE=90.66 90.57 89.3 9 90.3 9 90.50 90.5 0 90.50 91.00 90.99 91.0 6 90.9 1 90.99 90. 5 0 90.5 0 90.9 8 91.0 0 90.98 90.47 90.47 90.5 0 91.00 90.50 90.7 3 90.6 5 90.6691.0 0 90.66 90.8 7 90.9 0 90.1 6 90.1 5 (88.6 0 ) (88.6 8 ) 90.2 90.4 90.6 90.8 90.2 90.4 90.6 (90.17) 90.4 5 90.4 7 90.4 8 90.2 790.27 2. 0 % 2. 0 % 4. 4 % 89 . 5 5 89.50 89. 5 5 4.2% 89.3 6 90. 3 3 90 . 3 3 90.23 89.62 89.19 89.08 89.1389.23 88.90 89.19 89.5 0 89 . 4 8 89. 4 2 88.92 88.93 2.0% 6. 2 % 2.0% 2 - 5" RISERS RAMP 89 . 5 5 2.0% 90.8 9 90.5 0 MATCH EXISTING SIDEWALK (90. 1 1 ) 90.7 4 90.7 4 (90.10)90. 1 1 90.6 1 90 . 9 0 90. 9 0 90.9 0 90.9 2 90.6 5 90.7 3 90 . 7 3 91.0 0 91.0 0 90.9 0 3. 1 % 2. 0 % 2. 0 % 4. 7 % 5.0% RAMP RAMP PROPOSED RAIN GARDEN 6" CURB HEAD 88 . 2 9 88 . 2 9 89.2 9 89. 2 9 88.29 89.51 88.2 9 88 . 2 9 89.63 88.2 9 89.79 2' CURB CUT 8. 8 % 20 . 0 % 15 . 7 % 1.0% 0.6% 2.4% 1.2% 1.2% 2.2% 3.5% 2.2% 1.3 % 2.5% 0. 8 % 1. 2 % 0. 8 % 1. 4 % 0. 7 % 7.2% 3.8% 0. 2 % 4.0% 3.3% 1. 1 % 1.6% 1.4 % 1.1% 1.2% 0.8% 6. 6 % 1. 2 % 0.6%5.9%1.3%0.6%0.8%0.3%0.5% 1.5% 3. 3 % 2.4% Sheet Of 15 Sheets MA P L E M I X E D U S E 30 1 N o r t h H o w e s S t r e e t , S u i t e 1 0 0 Fo r t C o l l i n s , C o l o r a d o 8 0 5 2 1 E N G I N E E R N G I E H T R O N R N PH O N E : 9 7 0 . 2 2 1 . 4 1 5 8 ww w . n o r t h e r n e n g i n e e r i n g . c o m 11.10.16 C400 GR A D I N G P L A N NORTH ( IN FEET ) 010 10 20 30 1 INCH = 10 FEET CALL 2 BUSINESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR EXCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow.before you dig.Call R LEGEND: PROPOSED CONTOUR EXISTING CONTOUR PROPERTY BOUNDARY PROPOSED SPOT ELEVATION 33.43 PROPOSED SLOPES 1. THE SIZE, TYPE AND LOCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO VERIFY THE EXISTENCE OF ALL UNDERGROUND UTILITIES IN THE AREA OF THE WORK. BEFORE COMMENCING NEW CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR FOR ALL UNKNOWN UNDERGROUND UTILITIES. 2. REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS, UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION. 3. ALL CURB SPOTS SHOWN ARE FLOWLINE ELEVATIONS. ALL OTHER SPOTS ARE FINISHED GRADE ELEVATIONS. 4. ALL PROJECT DATA IS ON THE CITY OF FORT COLLINS VERTICAL DATUM NAVD88. SEE COVER SHEET FOR BENCHMARK REFERENCES. 5. THE LOWEST FLOOR (INCLUDING ANY BASEMENT OR CRAWL SPACE) AND ALL HVAC EQUIPMENT SHALL BE FLOOD PROTECTED ABOVE THE REGULATORY FLOOD PROTECTION ELEVATION. 6. A FLOODPLAIN USE PERMIT AND NO RISE CERTIFICATION WILL BE REQUIRED PRIOR TO ANY WORK OCCURING WITHIN THE FLOODWAY. 7. SEE THE FLOODPLAIN EXHIBIT (SHEET C800) FOR ADDITIONAL INFORMATION REGARDING WORK WITHIN THE FLOODPLAIN AND FLOODWAY. 8. REFER TO ARCHITECTURAL PLANS FOR HAND RAILING AND BOLLARDS. NOTES: 2.0% (47.45 ) EXISTING SPOT ELEVATION PROPOSED STORM PROPOSED VERTICAL CURB AND GUTTER PROPOSED SWALE FLOODPLAIN PROPOSED SUBDRAIN SD 1 GA R A G E G R A D I N G R E V I S I O N BR R 0 7 / 2 6 / 1 8 2 SO U T H P A T I O R E V I S I O N BR R 0 8 / 0 7 / 1 8 3 GA R A G E R A I N G A R D E N R E V I S I O N BR R 0 8 / 2 8 / 1 8 RECO R D D R A W I N G 12/15 Page 1 DURING CONSTRUCTION INSPECTION CHECKLIST To be completed by Construction Superintendent This checklist is to be completed during construction and included with the Overall Site and Drainage Certification. •Use “Yes” for items completed as described. •Use “N/A” for items that are not applicable to the site being certified. •If any blanks are “No,” attach an explanation referencing the item number below. I.Compaction A.All berms and embankments meet the compaction requirements as specified in the project geotechnical report or comply with the City’s standard, which is “soils should be compacted within a moisture content range of 2% below to 2% above optimum moisture content and compacted to 95% of the Maximum Standard Proctor Density (ASTM D698).” Compaction requires verification during construction. Provide testing log from contractor/engineer. II.Storm Drain Pipe Installation Requirements A.The pipe trenches have been compacted in accordance with Section 02225-3.07.A.1. of the Fort Collins Development Construction Standards (e.g., the trenches in the roadways are to be 95% of maximum density and all other areas are to be at 90%, both in accordance with ASTM D698). III. Riprap - FCSCM Vol.1, Ch.7, Sec.4.4.4.3 A.The riprap bedding is a granular bedding of the gradation and thickness indicated on the approved construction plans. B.A filter fabric was installed instead of granular bedding and is the material shown on the approved construction plans or was an approved equal. Provide documentation for an approved equal. C.The riprap is the gradation shown on the approved construction plans with a D50 of . D.The riprap thickness is as shown on the approved construction plans and extends to the horizontal limits shown. E.The riprap is buried to the depth indicated on the approved construction plans. (A minimum of 6 inches of soil is required.) IV. Permanent Erosion Control Fabric - FCSCM Vol.1, Ch.7 A.All fabric was installed per manufacturer’s specifications. V. Certification of Other Permanent BMPs - FCSCM Vol.2, Ch.8, Sec.2 & FCSCM Vol.2, Ch.12 A.All cut-off walls have been installed in accordance with the approved construction plans. (Cut-off walls are required for irrigation ditch crossings of storm drain pipes and at the end of flared end sections.) 12/15 Page 2 Permeable Interlocking Concrete Pavers Post-excavation infiltration rates are consistent with design infiltration capacity (for “full or partial infiltration” designs) Impermeable liner meets design specifications Impermeable liner attached to concrete perimeter wall Impermeable liner is not exposed Any penetrations of the impermeable liner have been sealed and checked for water-tightness. Meets specifications for: -Dimensions -Reinforcement -Footings Underdrain pipe is per design specifications At least one cleanout is provided per underdrain lateral Cleanout pipe is not perforated Cleanout covers are installed and watertight Underdrain is NOT wrapped in geotextile fabric Underdrain orifice plate installed at outlet structure Underdrain integrity tested after backfilling using TV and/or water test Base coarse (e.g., #2/4) has 90% fractured faces Bedding coarse (e.g., #89) is thoroughly washed Sub-base materials are installed and compacted according to manufacturer’s specifications PICP area is protected from construction site sediment, including runoff from the upstream catchment and Close Out 12/15 Page 3 Bioretention Cells Heavy equipment did not travel over bioretention cell during excavation Bottom of cell was “ripped” after excavation Photograph before/after “ripping” Bottom of cell is flat and level Photograph Excavated area is protected/surrounded by sediment/runoff control BMPs during construction Photograph Overflow inlet elevation is set above bioretention media per plan (typically 12 inches) Overflow inlet invert elevation is at least 3 inches below containment wall/berm (to direct overflow into inlet) Measure/record distance between inlet and top of containment wall/berm Upstream catchment drains to inlet Forebay is installed according to design specifications Forebay has flat, concrete bottom Outlet structure/overflow elevation is confirmed Measure/record distance from overflow to top of media filter Impermeable liner meets design specifications Impermeable liner attached to concrete perimeter wall Impermeable liner is not exposed Underdrain pipe is per design specifications At least one cleanout is provided per underdrain lateral Cleanout pipe is not perforated Cleanout covers are installed and watertight Underdrain is NOT wrapped in geotextile fabric Underdrain orifice plate installed at outlet structure Underdrain integrity tested after backfilling using TV and/or water test 12/15 Page 4 Filter Media Filter media composition is per design specifications Filter media was “machine mixed” by supplier prior to delivery Filter media installed flat and level Other Structural Components Containment wall/berm is continuous and level Landscaping Final landscaping does NOT include sod Final landscaping (wood/rock mulch) is flat and level Vegetation is planted according to landscape design specifications Verify that weed barrier is not installed Temporary irrigation installed If N/A, then verify that permanent irrigation is installed to establish/maintain vegetation Close Out Upstream catchment stabilized prior to diverting runoff into bioretention cell Signature: Name: Title: Email: Phone: Company: Address: FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com LANDSCAPE BUFFERS FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com RAIN GARDEN FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com ROOFTOP PLANTERS FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: www.northernengineering.com FORT COLLINS: 301 North Howes Street, Suite 100, 80521 | 970.221.4158 GREELEY: 820 8 th Street, 80631 | 970.395.9880 | WEB: 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