Bestall Collaborative Limited Planning Environment Construction Management Development

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1 November 18, 2017 Bestall Collaborative Limited Lori Hight, AICP, Senior Planner City Development Department City of Thornton City Hall 9500 Civic Center Drive Thornton, Colorado RE: River Valley Village Subdivision Amendment No. 3 SUBA (Hansen #8361) 4 th Submittal - Response to 3 rd Submittal CD Comments/Redlines Dear Lori. The following provides responses to City of Thornton and referral agency comments & redlines for the River Valley Village Subdivision Amendment No. 3 SUBA Construction Drawings (CD s) organized in an outline based on the redline/comments posted online. A. LANDSCAPE ARCHITECTURE (LA) CD GREELINES Page 1 B. DEVELOPMENT ENGINEERING (DE) CD REDLINES Page 2 C. DEVELOPMENT ENGINEERING (DE) DRAINAGE REPORT Page 6 D. DEVELOPMENT ENGINEERING (DE) UTILITY REPORT Page 7 Response to Comments A. LANDSCAPE ARCHITECTURE (LA) CDS (110717) Sheet C0.0 Cover. 1. Add detail for Multi-purpose trail (Regional Trail) from SS to Sheet C8.4. Response: Detail added. 2. Show irrigation tap locations with default 4 service lines and show all sleeves for irrigation. Response: Tap locations with proper tap sizes and sleeves indicated. 3. Add meter pit detail for lines over 1 because one of the lines is 1.5 on Sheet C8.6. Response: Reference Sheet C8.8 for meter pit detail (already exhibited0. Sheet C1.2 Grading Plan. 1. Trail is very close to drop-off into Ditch guard rails may be required. Response: Noted rails added. Sheet C1.4 Grading Plan. 1. Add handrail to plan that has vertical slats that a child cannot fall through. Response: Noted handrail added. Sheet C7.1 Water Plan & Profile 1. Drawings must show accurate Irrigation meter, tap and service line information. Response: Irrigation meter, tap and service line information coordinated with Landscape plans. 1

2 Sheet C8.4 Detail Sheet 1. Add Regional Trail detail from SS. Response: Added. B. DEVELOPMENT (DE) CDS (111417) Sheet C0.0 Cover. 1. Variance 3: need to state that the minimum 5 offset from the property line is being allowed to be reduced down to a minimum offset of 2. Response: Minimum 2 setback added to variance. 2. Variance 4: Add and Response: Revision added. 3. Variance 4: Please note this variance of A.1 does not include the part about the minimum separation of 5 between water service lateral connections to the water main. Need to state that the minimum horizontal separation of 10 is being allowed to be reduced to a minimum of 2, provided that the bottom of the water service is greater than 12 above the highest point on the top of the sanitary sewer service. Response: Noted variance text revised. 4. Add a variance for section B.1 to allow for 6 of cover instead of 18 of cover over the 18 RCP shown in Detail A on Sheet C1.1. Response: Variance text added. Sheet C1.1 Grading Plan. 1. Prior comment which instructed to Add General Note 4: All retaining walls with a vertical drop of greater than 30 will require a railing or fence at top of wall, or for multiple tiered walls, at the top of the top wall, (if any of the tiers have a drop of greater than 30 ) was not intended as a new note but as instructions to the designer. Response: if any of the tiers have a drop of greater than 30 deleted. Sheet C1.2 Grading Plan. 1. Comment from Planning - sidewalk was shown at the end of 98 th Place in the ODP-CSP and is expected to be provided. Response: The ODP/CSP is a guide not an inflexible construction document. Provision of a sidewalk at this location does not represent good design and increases impervious surface. We have requested that Planning reconsider the purpose of the sidewalk and assist in capturing an opportunity to soften the hardscape feel of the neighborhood. Sheet C1.3 Grading Plan. 1. Comment from Planning - sidewalk was shown at the end of Clermont Lane in the ODP-CSP and is expected to be provided. Response: The ODP/CSP is a guide not an inflexible construction document. Provision of a sidewalk at this location does not represent good design and increases impervious surface. We have requested that Planning reconsider the purpose of the sidewalk and assist in capturing an opportunity to soften the hardscape feel of the neighborhood. 2

3 2. As noted previously, the retaining wall cannot be within a utility easement. The wall is currently shown on the east side of the lot line, the same side as the utility easement. The wall needs to be on the west side of the lot line to be out of the utility easement. Adjust the utility easement or the wall to eliminate the conflict. Response: Revised retaining wall relocated to west. Sheet C1.4 Grading Plan no comments Sheet C1.5 Grading Plan. 1. A callout needs to be added to refer to the ditch reconstruction notes on Sheet C8.9. If no freeboard line is to be shown for the ditch, then the callout to be added here will need to be indicate that the required clay material will need to extend to the top of the bank for the section of irrigation ditch being reconstructed. Response: Callout added on Sheet C Within the limits of the irrigation channel, per the Colorado Agricultural Ditch Company Guidelines, the maximum permanent slope is limited to a maximum 2:1. The only exception to this requirement would be in the immediate vicinity of the tie-in to existing grades (using engineering judgement for tie-in taper length). Outside of the of the irrigation channel, permanent slopes are limited to a maximum of 4:1 per City standards and specifications. 3. Contours are shown connecting to the existing grade, but the area to the south (RVV Phase 2) is under construction now and the existing grade shown here does not appear to be the finished grade surface from Phase 2. The proposed grade cannot extend past the Phase 3 grading limits without a grading easement from the adjacent property owner. Suggest revising to show the proposed grading from Phase 2 as the existing grading in this area. 4. Arrow is backwards. 5. Trim proposed contour lines to tie-in points. Sheet C1.6 Grading Plan no comments. Sheet C2.1 Erosion Control Plan Phase 1 no comments. Sheet C2.2 Erosion Control Plan Phase 2 no comments. Sheet C3.1 Street Plan and Profile. 1. Comment on previous review was that the maximum grade break permitted without a vertical curve is 1.0% on private streets. Instead of revising design you changed the existing grade label to 2.75% to 2.92% so that the design met the 1% limit. Is 2.92% the existing slope? If not, you didn t fix the problem and the design needs to be revised. Response: Error made in Submittal 3; submittal 4 percentages correct. Sheet C3.2 Street Plan and Profile no comments Sheet C3.3 Street Plan and Profile no comments. 3

4 Sheet C3.4 Street Plan and Profile no comments. Sheet C3.5 Parking & Table Top Details. 1. Need to call out what kind of curb and gutter is being used for the locations where the sidewalk is being attached. Standard detail Section 2? (Typ) Response: Revised callout added. Sheet C3.6 Signage & Striping Plan. 1. Either add TYP callout for parking space dimensions, or add a note to the general notes on this sheet regarding parking space sizes. Response: Typical added. 2. Move sign to lot line to avoid conflict with adjacent drive. Sheet C4.1 Overall Utility Plan. 1. Add WV, move WV at 98 th Pl/Albion Lane. 2. Move curb ramp, shift meter pit east at 98 th Place/Ash Lane to provide a perpendicular connection to the water main. 3. Move WV s near 98 th Place/Ash Lane. 4. Move WV in between Lot 23C and 24C north of 98 th Place. 5. Service laterals on the same side of the main must have a minimum of 5 separation (Typical). Service laterals on the opposite side of the main may have a minimum of 2 separation (Typical). Response: Revised as required. 6. Meter pit symbol missing in front of 12C Block Per our previous meeting, the gap between the utility easement and the lot lines (in Block 7) was supposed to have been eliminated. Is this old linework? Response: Gap needed for landscape material easement is for main not service laterals. 8. Connection to the sanitary sewer and water mains must be perpendicular (Typical). 9. Add WV south of Lot 15C Block 7 in Ash Lane. 10. Whenever possible the water meter pit needs to meet the 5 separation between the side lot line. Response: Revised, as possible. 4

5 11. Move WV at 97 th Ave and Albion Way. 12. Irrigation meter pit may not be under sidewalk, move into a landscaped area (Typical). Response: Revised irrigation meter pits out from under sidewalks. 13. Add WV on 97 th Ave, east of Ditch. 14. Move WV at Birch Lane and 97 th Ave. 15. Retaining wall cannot be within easement move wall to west side of lot line (Block 9) 16. Add and remove WV s on Birch Lane. 17. Adjust WV s on Clermont Lane as required. 18. Relocate Storm manhole east to meet perpendicular separation requirements (see Storm Plan comments). Response: Revised relocated refer to Storm Sewer plans. Sheet C4.2 Utility Control Schedules. Sheet C5.1 Sanitary Sewer Plan & Profile. 1. As indicated in the previous review, please add a detail to show how the underdrain service is typically provided to each lot for one of these 4 to 5 plex units. (Typical comment for all sanitary sewer P&P Sheets. Response: Underdrain locations for each shell building indicated on each Sanitary Sewer plan and profile. 2. Add text to this note to indicate that an underdrain cleanout is to be provided at each manhole. Response: Text note added to each Sanitary Sewer plan and profile. Sheet C5.2 Sanitary Sewer Plan & Profile no comments. Sheet C5.3 Sanitary Sewer Plan & Profile no comments. Sheet C5.4 Sanitary Sewer Plan & Profile no comments. Sheet C6.1 Storm Sewer Plan and Profile. 1. Shift storm sewer east to eliminate the private storm sewer running parallel to the sanitary sewer and water within the exclusive easement, and to keep the crossings at substantially right angles. Sheet C6.2 Storm Sewer Plan and Profile no comments. 5

6 Sheet C7.1 Water Plan and Profile. 1. Need to call out the size and location for all 4 irrigation taps (typ). The meter pit must be in a landscaped area and not under the sidewalk. Revise locations as necessary. Response: Size and location call-outs indicated on Sheet 4.1 Overall Utility Plan. 2. See comments on Storm Sewer plans regarding relocating the storm sewer in this area. 3. List smallest cover provided, which would be at the east side. 4. Replace encasement labels with sleeve labels. 5. Graphically it looks like you are providing about 0.7 of clearance here instead of the 1.7 of clearance required. Sheet C7.2 Water Plan and Profile. 1. Need to call out the size and location for all 4 irrigation taps (typ). The meter pit must be in a landscaped area and not under the sidewalk. Revise locations as necessary. Response: Specific call-outs for size and location have been added. Sheet C7.3 Water Plan and Profile no comments. Sheet C7.4 Water Plan and Profile no comments. Sheet C7.5 Water Plan and Profile no comments. Sheet C8.1 Details no comments. Sheet C8.2 Details no comments. Sheet C8.3 Details no comments. Sheet C8.4 Details. 1. Add pedestrian rail detail for irrigation ditch headwalls. Response: Pedestrian rails added. Sheet C8.5 Details no comments. Sheet C8.6 Details no comments. Sheet C8.7 Details no comments. Sheet C8.8 Details no comments. 1. Add City of Thornton standard Detail 500-9, for the locations where the sidewalk is attached, adjacent to the perpendicular parking spaces. Response: Detail added. 6

7 Sheet C8.9 Details. 1. Maintenance and access road Note 3 current design does not provide this wide (16 wide travel surface) of a maintenance access road. Response: Access road/regional Trail has been approved by CoAgDitch and City for Crossing type 4.1.3, 4.2.3, (Design Criteria) see comments on Sheet 1.5. Response: Noted. 3. A detail must be provided for the railing, along with a reference as to where to find the detail within the plan set. See suggested detail added to Sheet C8.4. Response: Note added. 4. Where are the side slopes (grades). Response: Added. 5. Need to indicate slope of pipe. Minimum slope permitted per Colorado Agricultural Ditch Company design guidelines is 0.30%. Current slope shown is.019% Response: Slope revised to 0.3%. 6. The free board is not shown anywhere within these construction drawings. If no freeboard line is to be shown, then the clay material will need to be provided to the top of bank. A note will be needed on the grading plans. Response: Note added identifying the freeboard elevation. Sheet C9.1 Final Drainage Plan no comments. C. DEVELOPMENT ENGINEERING (DE) FINAL DRAINAGE REPORT (111417) 1. Page 1 Include a culvert capacity analysis for the two 4 x8 RCP irrigation culverts (83CFS, 0.3% slope). This information was previously provided in the utility report, but was deleted from the current submittal. Response: Included. 2. Page 1 Table of Contents Include a copy of the Drainage Basin Map (existing and proposed conditions) at the end of this report. Response: Included. 3. Page 76 of 93 Appendix B Design Point 21. Should be CDOT Type R grate. Need to capture the minor year flow in the inlet. May need to be a 10 Type R instead of a 5 Type R as shown in the CDs. 4. Page 76 of 93 Appendix B Design Point 21. Per detailed grading plans the maximum ponding depth for this inlet is 0.12 (1.4 ) before water spills over to the next basin. 5. Page 77 of 93 Appendix B Design Point 23. Minor opening should be 2 not 1. Need to capture the minor year flow in the inlet. Increase inlet to 10 as shown in the CDs. 6. Page 78 of 93 Appendix B Design Point 24. Per detailed grading plans the maximum ponding depth for this inlet 0.25 (3.0 ) before the water spills over to the next basin. Need to capture at least the minor year flow in the inlet, increase inlet length to 15 7

8 7. Page 79 of 93 Appendix B Trapezoidal Channel Design Point 10/21 (1 ). What is this channel section supposed to be representing? The flow over the speed table? If so, this section does not match the CDs. Please clarify. 8. Page 80 of 93 Appendix B Trapezoidal Channel Design Point 10/21 (1.5 ). What is this channel section supposed to be representing? The flow over the speed table? If so, this section does not match the CDs. Please clarify. 9. Page 81 of 93 Appendix B Trapezoidal Channel Design Point 24/25-1. What is this channel section supposed to be representing? The flow over the speed table? If so, this section does not match the CDs. Please clarify. 10. Page 82 of 93 Appendix B Trapezoidal Channel Design Point 23/ What is this channel section supposed to be representing? The flow over the speed table? If so, this section does not match the CDs. Please clarify. D. DEVELOPMENT ENGINEERING (DE) FINAL UTILITY REPORT (111417) 1. Page 16 Appendix Print out for max hour plus fire scenario is missing. Response: After clarification a print out of max day plus fire flow was included. If you require additional clarification, please contact me. Thank you. Jack Bestall Bestall Collaborative Limited 8