Lee's Summit

As discussed in an email dated May 13, 2022, our City standard detail is incorrect on curb inlets installed in the sump condition. Please change the note on the detail to include a 5 foot transition on each side of the curb inlet for the sump condition.

Sheet 14: How will the riser be plugged at the top? Will a plate be welded internally and concrete be placed in convex manner? Please show how this will be accomplished.

Please refer to the previous applicant letter comment 23. I had requested which lots would require an "as-graded" plot plan on the MBOE table, but it did not appear this was completed. Please update using your best engineering judgment on which lots will require an "as-graded" plot plan prior to occupancy. This is an aid to our development technicians group who perform plot plan reviews in conjunction with the Master Drainage Plan.

Labeling for the swales shown on Sheet 4 does not appear to correspond with the naming convention shown on the table in lower right hand corner of the sheet. I am showing the existence of 1-1, E-E, F-F, G-G, and H-H, but the table shows a different naming convention. Cross sections are provided using the E, F, G, and H designation, which further confuses the issue. Please reconcile.

Shee 13: The 100 year clogged condition/zero available storage WSE does not show the minimum 1.0 feet of freeboard between it and the top of the dam. Please correct.

Sheet 13: The nominal conditon 100 year WSE does not show the required minimum freeboard of 0.50 feet to the emergency spillway. Please correct.

Sheet 13: Public easements are shown for incoming storm lines and outgoing storm lines. These shall be removed since these lines are private lines from the last junction such as a curb inlet. In the case of the outgoing pipe from the detention basin, the outlet structure is also private, and shall not include an easement. Please correct, and ensure this comment carries-through to the final plat.

Sheet 13: Will the steel rods forming the trash rack on top of the outlet structure be welded? If so, please note on the plans.

Sheet 13: The trash rack for the 15 inch line entering the outlet structure shows a trash rack, but no details are shown. Please show details of construction of this trash rack.

Sheet 13: The trash rack for the 15 inch line is shown connecting to an HDPE flared end section. This should be called-out as RCP due to the trash rack. It is doubtful that a trash rack can be constructed against an HDPE flared end section. Please analyze and correct.

Sheet 13: A graphic representation of the 100 year WSE for the nominal and the clogged/zero available storage is required, along with dimensions from the closest property lines. It appears there may be instances where the minimum setback of 20 feet is not achieved. Please update and correct as appropriate.

Sheet 13: Construction details were missing for the outlet structure in terms of materials, steel reinforcement, thickness, orifice plate material and method of attachment, etc. Please include all construction details necessary to construct the outlet structure.

Sheet 13: Construction note for the trash rack on top of the outlet structure references placement above a v notch weir which does not appear to exist on this structure. Please evaluate and correct.

Sheet 13: Notation of the rip rap refernces other details, but the sheet number is not included. Also, calculations are missing. Calculations of rip rap design is required for all areas receiving rip rap. Please analyze and update as appropriate.

Sheet 13: Recommend a profile view of the outlet structure in relation to the fill of the dam. It does not appear the configuration shown will work, given that the 1008 contour is at the west edge of the outlet structure, and the outlet structure weir opening is at 1007.25, approximately 9 inches below grade. Finally, the outlet structure 3901 cross-section on this sheet does not match what is proposed. It appears this is a generic detail without the trash rack on top, and was a generic detail for a closed top design. Please revise.

A cross-section of the dam is required at the highest point, along with slope callouts, the minimum 3 foot wide flat spot at top of dam, bottom of dam, and bottom of detention basin. Please revise as appropriate.

Sheet 13: Line 3900 is missing the HGL for the design storm (i.e., the 100 year event). Please revise.

Sheet 12: Storm line 1000 is discharging stormwater in the supercritical regime due to excessive slope. Either change the slope of the pipe, or provide a different energy dissipation method as shown. As shown, the discharge point shall experience severe erosion issues.

Sheet 11: Line 200 is likely flowing in the supercritical regime at the outfall. Recommend lessening the slope to create a hydraulic jump within the pipe, or provide a different method for energy dissiipation. Please analyze and revise.

Sheet 11: Line 700 is discharging in the supercritical regime. See above comments concerning the lessening of this slope to create a hydraulic jump within the pipe, or provide a different method for energy dissipation. Please revise as appropriate.

All ADA-Accesible Ramp Detail Sheets: The turning spaces are mostly non-compliant at all parallel ramps. The requirement is that a design slope of 1.5% be designed for all turning spaces in any direction. A quick check of these turning spaces at parallel ramps using the elevation callouts shows a design slope in excess of 1.5% in the diagonal direction. Please analyze, and revise as appropriate.

Sheet 7 or Elsewhere: There is no indication of the start and stop point for construction of the ADA-accessible ramps. A clear indication of where the stop and stop point shall be shown. At an absolute minimum, the ADA-accessible ramp construction shall be carried to the turning space, and in the case of wrap around curb return ramps, shall be extended around the curb return. Please revise as appropriate.

Detention basin bottom slope callouts were not provided on Sheet 13. Please keep in mind 2% slope is not necessarily required, and may allow additional storage for this basin. The City has not adopted the MARC manual, but the MARC manual allows for slopes less than 2% and actually encourages slopes less than 2% in the basin bottom for water quality benefits. Please analyze, and revise as appropriate. Please show the slope calluts, and ensure any grading elevations callouts match the outfalls of the three (3) incoming pipes as well as the outgoing pipe elevation.

HGL calculations shown on the table and the profile views of the storm lines did not appear to take into account the HGL for the various storm events related to the detention basin. At least one storm line appears to surcharge out of the curb inlet at Line 1000 during the 100 year clogged event. Overflow swales at this location are required. Please analyze and revise as appropriate.

It is recommended the outlet structure be moved to the south end of the detention basin to allow more residence time for the stormwater. As shown, short-circuiting of the water quality aspect of the design will occur using the geomety shown.

Sheet 3: Table at upper right does not show the lots where an as-graded plot plan is required. Please show which lots require an as-graded plot plan.

Sheet 3: Swales are called-out without the required details. Cross-sections shall be shown at the beginning of the swale, the ending of the swale, and key locations along the swale (e.g., 25 feet?). The generic detail at the bottom of the sheet is not sufficient for swale detailing. Please update and revise as appropriate.

Sheet 3: Swale B-B is not properly detailed in terms of contours lines. This appears to be an overflow swale for the surcharged curb inlet which will not be able to manage any flow when the detention basin is at capacity for the 100 year nominal event. An emergency overflow swale is warranted at this location, and shall follow all previous comments related to swale detailing described elsewhere in this comment letter. Please analyze and revise as appropriate.

Private storm line 1000 between the lots 11 and 12 is too close to the building lines on each lot. Assuming the utllity is centered, 11 feet on each side of the easement appears warranted. Please correct, and ensure this is carried-through to the plat.

Recommend separate sheet(s) for swale construction, including the emergency overflow swale, and other swales described elsewhere in this comment letter. Please revise by providing a separate sheet(s) for these features.

Detention basin is shown within the stream buffer, which is acceptable as long as the foreslope of the dam to the midpoint of the top of dam is considered. Any other extension of the detention basin into the buffer is considered an encroachment. There is one (1) area that is considered an encroachment, and will need to be moved outside the limits of the stream buffer unless: 1) a stream assessment and waiver is obtained for the encroachment. Please revise using these guidelines, or perform the stream assessment and waiver.

Sheet 14: Asphaltic concrete type was not specified on the section view. Please see the Design and Construction Manual for specific options, and update and revise as appropriate.

The trench backfill detail was incorrect. Please use the new standard that was updated in July 2020 which requires a minimum of 12 inches aggregate over the top of pipe. Please revise as appropriate.

Please remove the PCC concrete table. Unless this is being shown with a jointing and sawcutting design, it is irrelvant to the plans.

Please see comments related to The Manor at Bailey Farms 1st Plat in regard to the Final Stormwater Management Report dated Jan. 31, 2022 (hereinafter referred to as the stormwater study). All comments related to The Manor at Bailey Farms 1st Plat apply to this phase of the project.

The final stormwater report pond setup table within the appendix shows an invert elevation of 1000.0 for device #2, the incoming 15 inch pipe. This does not agree with the plans, which show the elevation at 997.91. Please reconcile, as this will have a significant impact on routing calculations.

The final stormwater report shows RCP from the outlet structure to the creek. The plans show HDPE. Please reconcile, and please callout RCP for this area as a suggestion.

Storage volumes shown for the various events within the stormwater report do not appear to agree with those shown in the table of the plans on Sheet 13. Please reconcile.

Sheet 13: The small inset detail showing the emergency spillway contains contradictions. One part of the detail shows the spillway with a different elevation than shown elsewhere, and

Sheet 13: Access hatch is shown at a questionable location. How will this hatch be used to clean the orifice when it is located on the opposite side, and not centered over the orifice plate? Please analyze and revise as appropriate.

To avoid confusion, please label the detention basin as EDDB 1 to match what is shown in the final stormwater report. This should be shown on general layout sheet and detention basin sheet.

Submittal is missing the required Final Stormwater Detention and Stormwater Management Report. Even though a preliminary report exists, a final report shall be required. No further review of the detention basin shall be provided as part of this comment letter in regard to volume, elevations of weirs, emergency spillways, etc.

Stream buffers were not shown anywhere within the plan set, except for Sheet 2 . This shall be require on additional sheets such as the detention basin.

Profile views of all storm lines are missing the design storm HGL. Recommend at a minimum to size the lines for 100 year event to a point no less than 6 inches below throat of any inlet, and 10 year event contained below pipe crown (i.e., gravity flow governed by mannings). If 100 year event cannot be contained within pipe under pressure flow, then overflow routes including swales for the incremental increase that the underground system is not able to manage, shall be required. In addition, MBOEs shall be required for adjacent lots if the underground system is unable to manage the 100 year event. Please analyze and revise as appropriate.

Typical pavment section view shows a generic residential street. Generic section views are not allowed. The section view shall be revised to show which streets the section pertains.

Master Drainage Plan is incomplete. Please contact this office for an example of an acceptable Master Drainage Plan showing the required elements. No further review performed at this time. Missing items included: 1) existing and finished lot corner elevations, 2) swale D-D does not appear to match what is shown on the table, versus what is shown on the grading contours, 3) swale 1-1 is shown on the plan view, but not defined anywhere on the table, 4) swale B-B and C-C are defined in the table but not shown anywhere, 5) MBOEs are called out, but not specified, 6) basement type for each lot was not shown (i.e., standard, daylight, or walkout), and 7) lack of the 100 year water surface elevation within the detention basin being shown in graphic format on the Master Drainage Plan, along with dimensions to property lines to ensure there is a minimum 20 foot setback.

Intersection Detail Sheet is incomplete. ADA-accessible ramps do not include the required detailinig necessary to review, construct, and inspect. No further review was performed. In addition, the sidewalk shown extending around the entire cul-de-sac bulb is not desired by the City. The sidewalk should either enter the cul-de-sac in a straight fashion, or 90 degree parallel ramp fashion. No receiver ramp would be required. This particular ADA-accessible ramp shall be required to be shown and detailed. Please ask if examples are needed for this type of ramp (i.e., the end of cul-de-sac style ADA-accessible ramp).

Signage plan was missing. Therefore, I cannot comment on intersections with stop control and required ADA-accessbile routes across the intersection. Ensure that a signage plan is provided, and all factors including stop control or no stop control are considered in the design of the cross slope in the pavement, as well as proper placement of stop signs in relation to a crosswalk, despite it not being a painted crossswalk.

Are ADA-accessible ramps and/or sidewalk included in the previously-submitted Manor at Bailey Farms 1st Plat along Bailey Farms Pkwy.? Otherwise, termination of the sidewalk along Bailey Farms Pkwy. will be an issue. This shall require revison to the Manor at Bailey Farms plans to rectify any deficiencies in these plans.

Emergency spillway design is shown on the Master Drainage Plan which is not appropriate placement for this feature. This shall be required on the detention basin design sheet(s).

Pavement typical section view missing the asphaltic concrete type for the base and surface course. Please see Design and Construction Manual for choices.

Why is the Master Drainage Plan shown in various "pieces" throughout the plan set? The most important piece is shown on Sheet 3, then later parts are presented later in the plan set on Sheet 8 and 9. Recommend placing all of these sheets together within the plan set.

General Comment Concerning the Incomplete ADA-Accessible Ramp Design: The concept design is acceptable to the City, but wings shall be eliminated. Grading at a maximum of 3:1 shall be provided to the sidewalk edge rather than providing sloped wings. See also comments about the sidewalk extending around the cul-de-sac bulb. The City does not desire sidewalk extending around the cul-de-sac bulb. Straight entry or 90 degree parallel ramp is required, along with appropriate design and detailing.

A trenching and backfill detail for the storm lines was not provided and is required. Ensure new standards are used which require 12 inches of aggregate on top of pipe.

Detention storage and other statistics were shown on the Master Drainage Plan, which is not appropriate placement. This shall be shown on the detention basin design sheet(s).

Detention Basin Design Sheet: This shall show the proposed basin storage in cubic feet or other unit described in the final stormwater report, along with all other information provided on this sheet. Please see previous comment, however. The City did not receive a final stormwater report, so no further review shall be performed at this time.

Sheet 13: Please change title of this sheet to detention basin design or equivalent. It is more than a water quality structure detail sheet.

Sheet 13: Please specify the 100 year overflow with sufficient notes specifying what the 1010.13 elevation refers to. As it is shown in the section view detail, it is unclear and confusing.

Sheet 13: It is not clear how this basin shall provide 40 hour extended detention without a perforated riser, or other method to limit flows for the 90% mean annual event and hold it for 40 hours. We will wait to review with the final report which was not included in the submittal package.

Sheet 5 - Silo St.: Sta. 10+69.75 and 14+25.00, sag k-value too low (min. 20)

Sheet 5 - Silo St.: Sta. 10+78.63 Horizontal curve radius too tight (min. 200').

Please provide a signing plan.