| Review Type |
Outcome |
Est. Completion Date |
Completed |
|
Record Drawings Review
|
No Comments
|
11/29/2022
|
11/21/2022
|
|
|
Sue Pyles, P.E.
|
|
|
|
|
Engineering Review
|
Approved with Conditions
|
09/01/2020
|
08/31/2020
|
|
|
Gene Williams, P.E.
|
|
|
|
|
Engineering Review
|
Approved with Conditions
|
08/07/2020
|
08/06/2020
|
|
|
Gene Williams, P.E.
|
|
|
|
|
Engineering Review
|
No Comments
|
05/29/2020
|
05/29/2020
|
|
|
Gene Williams, P.E.
|
|
|
|
|
Engineering Review
|
Approved with Conditions
|
11/07/2019
|
10/31/2019
|
|
|
Gene Williams, P.E.
|
|
|
|
|
Traffic Review
|
No Comments
|
10/11/2019
|
10/10/2019
|
|
|
Michael Park
|
|
|
|
|
Engineering Review
|
Corrections
|
10/11/2019
|
10/09/2019
|
|
|
Gene Williams, P.E.
|
|
|
Corrective Action Required
Page 3-3 of the "Final Stormwater Management Plan" dated Oct. 3, 2019 states that "...to reach the 900.65 elevation, there would have be effectively 15.8 inches of rain (two 7.90 inch 100 year events) in a 48 hour period and zero discharge from the nearly 18 square feet of the outlet opening." We do not agree with this, since clogging of the primary outlet structure can occur without a 100 year storm event. Also, isn't the outlet opening 36 square feet rather than 18 square feet?
|
|
|
Corrective Action Required
It would appear the 100% clogged/zero available storage 100 year water surface elevation will encroach upon Lots 1474 and 1473. Can the grading on these lots be revised, to remove the encroachment? Can the outlet structure sizing be increased, and/or the 48 inch pipe be increased? There is mention of the outlet structure acting under inlet control during the clogged condition, but as was evident during the upsizing of this structure from a 5 foot by 5 foot top, to a 6 foot by 6 foot top, the 100 year water surface elevation for the clogged condition/zero available storage decreased. Internal discussions concerning this issue were relayed to you in a previous email, where it was concluded that the 100% clogged/zero available storage 100 year water surface elevation should be fully-contained within the tract boundary.
|
|
|
Corrective Action Required
We received the application for the United States Army Corps of Engineers (USACE) 404 permit, but will need the actual USACE permit prior to formal approval of the plans.
|
|
|
|
|
Engineering Review
|
Corrections
|
09/18/2019
|
09/18/2019
|
|
|
Gene Williams, P.E.
|
|
|
Corrective Action Required
Please refer to comment #5 of the previous applicant letter. The clogged condition analysis contained within the revised "Final Stormwater Management Plan" dated Aug. 23, 2019 is missing the "zero available storage" condition. It appears that only a clogged condition was evaluated, not the "zero available storage" condition. For instance, Page 4 of the clogged condition analysis within the appendix presents a table of cumulative storage that is less than the elevation of the emergency spillway. Since the "zero available storage" condition should have also been evaluated, anything less than the elevation of the emergency spillway should have been shown with zero cumulative storage.
|
|
|
Corrective Action Required
A 5 foot by 5 foot inside dimension outlet structure is not sufficiently wide enough to accommodate a 48 inch HDPE. It appears that wall thickness of the HDPE was not taken into account in the design. A minimum of 6 inches is required from the outside of the pipe, and the wall of the outlet structure.
|
|
|
Corrective Action Required
Sheet 18: Please add a note on the profile view of the scour basin that shows: 1) the width of the scour basin bottom, and 2) the side slopes. Although a table is provided on Sheet 17, wouldn't it be better to call this out on the profile view, to avoid any confusion in the field?
|
|
|
Corrective Action Required
It is likely the 48 inch HDPE is insufficient to manage the 100% clogged/zero available storage condition without significantly impacting adjacent properties. As indicated in previous comment letter (i.e., comment #6 and #7), increasing the pipe size is likely required, in additon to an increase in the outlet structure sizing to accommodate this larger pipe size.
|
|
|
Corrective Action Required
Prior to formal approval of the plans, a copy of the MDNR land disturbance permit is required, as well as any USACE permits (if applicable).
|
|
|
|
|
Engineering Review
|
Corrections
|
08/21/2019
|
08/21/2019
|
|
|
Gene Williams, P.E.
|
|
|
Corrective Action Required
Please refer to the previous comment letter. We had requested a site-specific design for the scour basin (i.e., structure 500). Although a table was presented, we are still missing the following: 1) width of the scour basin, and 2) side slopes. Although a note is provided in the generic table stating that the width of the scour basin shall be based on receiving swale width, or diameter of the discharge pipe, this determination should be performed by the engineer, not the contractor in the field.
|
|
|
Corrective Action Required
Discrepancies continue to exist in the "Final Stormwater Management Plan" dated Aug. 6, 2019 (hereinafter referred to the stormwater report). For instance: 1) Table 3-2 shows the proposed drainage to release point R1 as 195 cfs, contradicting the appendix showing 233 cfs on 18-230 PROP ANALYSIS-1, 2), peak elevation within the detention basin shown on 18-230 PROP ANALYSIS-1 SHOWS 895.44, which is highly suspect when compared with Sheet 18 of the plans, where the discharge at that elevation is approximately 80 cfs, and also contradicts the stated 100 year water surface elevation of 898.1, 3) Sheet 18 of the plans shows the stage/discharge relationship at 207 cfs (roughly coinciding with the outflow shown on 18-230 PROP ANALYSIS-1 OF 209 cfs) of 899 feet elevation rather than 898.1.
|
|
|
Corrective Action Required
The appendix within the stormwater report was missing the proposed conditions analysis for the 2 and 10 year events. Only the 100 year and the WQV storms were presented for the proposed conditions.
|
|
|
Corrective Action Required
There is no discussion or mention of the 100 year water surface elevation within the body of the report. Only the clogged condition, zero available storage 100 year water surface elevation is discussed. Please discuss within the body of the report, and ensure it matches what is shown elsewhere within the appendix and plans. The discussion should also discuss the nominal (i.e., fully-functioning) 100 year water surface elevation, and the crest of the emergency spillway, and whether the 0.5 foot minimum freeboard is maintained. Finally, page 4-1 of the report under "Summary and Recommendations" states that the detention basin meets the requirements of Section 5600 of the KCAPWA, which should be expanded in terms of the discussion to state that: 1) the release rates were compared to the pre-development peak flow rates, and used to determine the allowable peak flow rate.
|
|
|
Corrective Action Required
Where are the calculations for the 100% clogged/zero available storage hydraulic grade line? It did not appear any such calculations were provided, but only stated.
|
|
|
Corrective Action Required
Sheet 18: The 48 inch discharge pipe is missing the 100 year hydraulic grade line. Since the 100 year event is the design storm for this particular line, it should be shown on the profile view. However, please see the comment (below) concerning upsizing this pipe. Allowing the 100% clogged/zero available storage 100 year water surface elevation to extend almost 4 feet above the nominal condition is in our opinion, not a good idea.
|
|
|
Corrective Action Required
The previous comment letter asked for an engineer's opinion concerning the 100% clogged, zero available storage water surface elevation for the 100 year event. No such opinion was provided. There was a statement on page 3-3 of the stormwater report that says "...with 6 inches of freeboard the proposed and future MBOE shall be set no lower than 902.35." The City of Lee's Summit requires a minimum of 2.0 feet of freeboard between the 100 year hydraulic grade line, and MBOEs, not 6 inches. The bigger question, however, is whether the allowance for a clogged condition, zero available storage water surface elevation to extend almost 4 feet higher than the nominal 100 year water surface elevation. We feel this is too great a magnitude of change when compared with the nominal (ii.e., fully-functioning) condition. It may be better to provide a larger detention basin outlet structure (and a larger emergency spillway), along with a larger diameter discharge pipe than the proposed 48 inch HDPE. If the detention basin outlet structure were to clog, it would appear to flood the lots almost to the limits of the future homes. We do not support a 6 inch freeboard between this condition, and any MBOEs on the lots.
|
|
|
Corrective Action Required
MBOEs were provided for each lot as requested, but the table appears redundant, along with disrepancies between what is shown on the table, and the call-outs on the plan view (e.g., N/A is provided for several lots, but call-outs are given for each lot on the plan view). It may be better to delete this table entirely since MBOEs are called-out on the plan view for corners of the homes.
|
|
|
Corrective Action Required
Prior to formal approval of the plans, a SWPPP, and a USACE permit (if applicable) shall be required.
|
|
|
|
|
Traffic Review
|
No Comments
|
07/11/2019
|
07/11/2019
|
|
|
Michael Park
|
|
|
|
|
Engineering Review
|
Corrections
|
07/11/2019
|
07/11/2019
|
|
|
Gene Williams, P.E.
|
|
|
Corrective Action Required
The "Final Stormwater Management Plan" dated June 5, 2019 (hereinafter referred to as "the stormwater report") discusses on Page 2-1 that cover types were considered to be a pasture in poor condition. Although curve numbers were adjusted downward, it appears this comment was never removed from the report.
|
|
|
Corrective Action Required
The stormwater report used a composite curve number of 80 for the pre-developed condition. While we agree this curve number may be representative of soil group D, it does not appear that any relevance of soil group C was considered. It would appear the pre-development curve number should be adjusted downward slightly.
|
|
|
Corrective Action Required
The stormwater report still shows the same time of concentration of 21.4 minutes for the pre-developed condition. Previous comments contained in the April 10th applicant letter questioned the validity of this time of concentration value. It appears low for the pre-developed condition.
|
|
|
Corrective Action Required
While we will support the pre-development versus post-development analysis for the waiver request, we will not support elimination of the 50% and 10% storm events. It was our understanding that any waiver request to the flat release rate would be substituted by a pre-development versus post-development peak flow rate analysis for the 1%, 10%, and 50% events, as well as the 90% mean annual storm event.
|
|
|
Corrective Action Required
Page 3-3 of the stormwater report presents Table 3-3. Table 3-3 presents what appears to be an "emergency overflow water surface elevation" of 894.43, and 899.53 for the WQv storm, and the 100 year storm respectively. What is meant by this table? It does not appear to match anything shown within the appendix.
|
|
|
Corrective Action Required
The stormwater report discusses 4-48 inch orifices on Page 3-3. Aren't these weirs?
|
|
|
Corrective Action Required
Stormwater Report Appendix: 18-230 PROP ANALYSIS 1: the peak elevation of 895.44 is within 0.06 feet of the emergency spillway elevation, or at least that is what is shown on Sheet 18 (i.e., the top of the outlet structure is shown at 895.50, and is labeled as the emergency overflow). This does not comply with the minimum 0.50 feet between the nominal 1% storm event water surface elevation, and the crest of the emergency spillway.
|
|
|
Corrective Action Required
Table 3-3 within the stormwater report presents the "Emergency Overflow Release" of 154.56 cfs for the 100 year storm, with the primary outlet elevation shown at 890.90. This would appear to be the location of the weirs described in the above comment. It was our understanding from the body of the report, and the plans, that the emergency overflow weir was on the top of the outlet structure, at a higher elevation (i.e., 895.50). Please reconcile what is being proposed both on the table, the body of the report, and the plans.
|
|
|
Corrective Action Required
Revisions to the stormwater report, and plans would appear to be warranted based on the above comments.
|
|
|
Corrective Action Required
Please refer to comment #2 of the previous applicant letter dated Apr. 10th. We had requested the 50% and 10% storm event calculations, but the response stated that it was your understanding that only the 1% storm event and the 90% annual mean event would be considered. We do not agree.
|
|
|
Corrective Action Required
Please refer to comment #15 within the previous applicant letter. The location of the ADA-accessible ramps shown within the cul-de-sac bulbs is correct, but they need to terminate in a straight line (i.e., not at a right angle as shown). Please contact me if you need a sketch. If possible, attempt to locate these at the property line.
|
|
|
Corrective Action Required
Please refer to comment #16 within the previous applicant letter. The 100 year water surface elevation is now shown at 894.47, but this does not agree with Sheet 18 of the plans, or the appendix contained within the stormwater report. Sheet 18 and the appendix show the 100 year water surface elevation at 895.44, while the Master Drainage Plan shows this elevation at 894.47.
|
|
|
Corrective Action Required
It now appears the 100 year water surface elevation is too close to property lines. The City requires a minimum of 20 feet between the nominal 100 year water surface elevation, and any property line or building.
|
|
|
Corrective Action Required
Please refer to comment #18 within the previous applicant letter. The City of Lee's Summit now requires an MBOE for each lot. This is specified in the Design and Construction Manual.
|
|
|
Corrective Action Required
Please refer to comment #27 within the previous applicant letter. Although Sheet 17 now shows a scour basin, it is lacking essential information for a contractor and inspector to construct. The City requires a specific plan for the scour basin. This must be in a form that shows the width, depth, side slope, length, rock type, etc., in a clear and concise manner. As presented, only a portion of the information is provided, and a contractor and inspector are forced to look up the partial information by "table lookup". Missing variables include the width of the scour basin, any taper, plan view, etc.
|
|
|
Corrective Action Required
As indicated in your response letter, a SWPPP is in progress, and will be submitted, as well as any USACE permits (if applicable).
|
|
|
Corrective Action Required
Where is the clogged condition water surface elevation? Please discuss within the body of the stormwater report, and discuss any potential issues related to property damage due to flooding, or any roadway overtopping issues. Provide an engineer's opinion concerning the use of the nominal (i.e., unclogged condition) 100 year water surface elevation, or the clogged condition 100 year water surface elevation in relation to MBOEs, or property lines. Since there appears to be less than 20 feet from the property line of Lot 1474 and the nominal 100 year water surface elevation, would it be more appropriate to use the clogged condition 100 year water surface elevation?
|
|
|
Corrective Action Required
Sheet 12: While the General Layout sheet shows sidewalk to be constructed along unplatted land, this specific sheet does not appear to show this. Please add appropriate notes.
|
|
|
Corrective Action Required
Sheet 14 and 15: The cross-sections are generic rather than site specific. Cross-sections must be shown which provide the design cross-slope, running slope, width, and where sidewalk curb is or is not necessary (i.e., the generic detail provided on your plans states "sidewalk curb as necessary").
|
|
|
Corrective Action Required
Sheet 14 and 15: Where are the locations of the truncated dome tactile warning strips? Please show their location, along with dimensions from the longest distance from the back of curb. This maximum distance is 5.0 feet.
|
|
|
|
|
Traffic Review
|
Corrections
|
04/09/2019
|
04/09/2019
|
|
|
Michael Park
|
|
|
Corrective Action Required
The proposed islands in the cul-de-sac(s) should be removed or moved to a location within the cul-de-sac and re-designed for the accommodation of traffic to circulate the bulb (a SU truck and P vehicle) similar to the islands within the adjacent cul-de-sac(s) of Winterset Valley (e.g. Audubon Ln).
|
|
|
|
|
Engineering Review
|
Corrections
|
04/09/2019
|
04/09/2019
|
|
|
Gene Williams, P.E.
|
|
|
Corrective Action Required
Why was the pre-versus-post development methodology used, rather than the flat release rates? It was our understanding that the temporary measure in the previous phase could utilize that methodology on a temporary basis. However, that was never implemented, as permission was granted from the adjacent property owner for un-detained release. It is our position that the new standards (i.e., flat-release rates and 40 hour extended detention) be provided.
|
|
|
Corrective Action Required
The "Final Stormwater Management Plan" dated Mar. 15, 2019 (hereinafter referred to as the stormwater study) was missing the 2 and 10 year events.
|
|
|
Corrective Action Required
The stormwater study discusses the curve numbers for the existing condition, but the existing condition should have been made based on the conditions prior to any development. As shown, it appears the existing condition curve numbers were derived for conditions as they currently exist, which was not the intent. When the City agreed to allow the detention basin to be constructed later in the 13th phase (i.e., this phase), it was our understanding that "existing conditions" would mean the conditions that existed prior to any development. Based on this rationale, many of the time of concentration calculations for the existing condition should be re-evaluated based on the "previously existing conditions", as well as curve numbers, peak flows, etc.
|
|
|
Corrective Action Required
Page 2-3 of the stormwater report discusses the Corps of Engineers review, but makes no further comment concerning the need for USACE permitting. Will a USACE permit be required?
|
|
|
Corrective Action Required
Page 3-1 of the stormwater report discusses the un-detained 4.34 acre drainage area, with no further information, rationale, or request for waiver for the un-detained release. Please expand, and discuss the rationale behind this request.
|
|
|
Corrective Action Required
Existing peak flow rates for the 100 year event are presented on page 2-2 of the report. However, the figure of 262 cfs for the 100 year event does not appear to agree with the results contained within the appendix, which appear to show a pre-development peak flow rate of approximately 200 cfs.
|
|
|
Corrective Action Required
Page 2-2 of the stormwater report shows an existing time of concentration of 21.4 minutes. This appears to be low. Also, the paragraph above Table 2-1 discusses the 10 year and 100 year design storms being presented, but the 100 year event appears to be the only event presented. Finally, the same paragraph discusses a Table 2-2, which was not presented in the report.
|
|
|
Corrective Action Required
Table 2-2 of the stormwater report shows an existing condition curve number that is exactly the same as the post-development condition. We do not agree with this conclusion. As previsouly discussed in this comment letter, the existing condition should reflect the conditions that existed prior to any development on the project site. The existing condition would therefore, be a pre-development condition rather than an existing condition.
|
|
|
Corrective Action Required
Where in the stormwater report was the MARC worksheet provided for sizing the orifices within the outlet structure?
|
|
|
Corrective Action Required
Where in the stormwater report is the emergency spillway system addressed? There are various options available, but it is preferred that the emergency spillway be incorporated into the primary outlet works rather than over the road. When calculating the 100% clogged, zero available storage condition, the emergency spillway is NOT considered clogged if an overflow weir is constructed separate from the system of orifices and weirs which are part of the primary outlet works.
|
|
|
Corrective Action Required
The stormwater report must discuss the allowable release rates, preferably in table format, along with a discussion of the primary outlet works, the emergency spillway, also in the preferred table format. It should present the flowline elevations of all orifices, weirs, spillways, 100 year water surface elevations for the nominal and clogged condition/zero available storage. As presented in the stormwater report, there is no discussion of these critical items. An appendix is shown, but we are not familiar with this particular software, and without a clear understanding of where each element is shown within the appendix, it is impossible to determine what is being proposed.
|
|
|
Corrective Action Required
The soil map in the appendix presents a soil group 10120, but it does not appear to have been accounted in the area of interest table.
|
|
|
Corrective Action Required
Timesteps within the appendix appear to show 6 minutes. It is our understanding that timesteps should be approximately 0.1333 times the time of concentration, in order to provide accurate results. Given a 20 minute time of concentration, this equates to approximately 2.5 minutes, not 6 minutes.
|
|
|
Corrective Action Required
What is the purpose of the depth versus discharge curve shown on Page 5, 18-230 PROP ANALYSIS for the 100 year event at REACH 2PR: PROP STREAM, which shows discharge from 0 to 700,000 cfs? This would appear to be irrelevant information given the scale. If it is still desired to present this information, please use an x-axis which is relevant to the situation. There are several examples of this type of curve presented elsewhere in the appendix, and given the scale, it does not appear useful since a flow of 500,000 cfs is on the order of the Mississippi River.
|
|
|
Corrective Action Required
Sheet 7, General Layout: ADA-accessible ramps are not shown correctly. The City policy for ADA-accessible ramps at the end of cul-de-sacs has changed over the last two years, and our current policy is to terminate the ADA-accessible ramp in a straight line, into the cul-de-sac bulb. There are two (2) ADA-accessible ramps on this project, and both should terminate at a location near the northeast corner of Lot 1478, and the southwest corner of Lot 1481. Please revise this sheet, and any subsequent sheets as appropriate.
|
|
|
Corrective Action Required
Master Drainage Plan (All Sheets): The 100 year water surface elevation must be shown, preferably in graphic format (e.g., areal extent boundary), along with an elevation call-out.
|
|
|
Corrective Action Required
Master Drainage Plan: It would appear that a swale should be designated along the rear of Lot 1483, in addition to the swale called-out downstream of this location.
|
|
|
Corrective Action Required
MBOEs must be called-out for each lot. There are several lots that are missing an MBOE.
|
|
|
Corrective Action Required
Many of the lots are missing the finish grade. Even if no work is being done in the form of re-grading, the finish grade needs to be called-out. It can be as simple as stating "EX Grade = Finish Grade", or equivalent language.
|
|
|
Corrective Action Required
The swale above Line 200 would appear to be a designated emergency overflow swale. Please designate this important distinction on the Master Drainage Plan.
|
|
|
Corrective Action Required
Please label the detention basin. As presented, it is merely shown as Tract D12, Winterset Valley 12th Plat.
|
|
|
Corrective Action Required
All Areas With Rip Rap: A specific call-out is needed rather than a table for the instructions to the contractor and inspector concerning the rip rap sizing, type, geofabric, dimensions, and thickness. The table may be helpful, but a specific call-out is needed for each area.
|
|
|
Corrective Action Required
Sheet 14: The plans were missing the ADA-accessible ramp details, and are also missing a comprehensive listing of which sidewalks will be constructed during home construction, which will be constructed with the road improvements (i.e. along common area tracts, unplatted property), and ADA-accessible ramps (which are required to be constructed with the road improvements). Please see the 11 bullet-point items contained within Section 5304.8 of the Design and Construction Manual. These items must be included in the design details for each ADA-accessible ramp.
|
|
|
Corrective Action Required
The plans were missing the ADA-accessible route details across intersections under stop control. In addition, the profile view of the roadway sections must be updated to clearly-show the locations of these stop-controlled intersections. Please use the City of Lee's Summit design standards (i.e., 1.5% cross-slope, 7.5% running slope) as a design standard rather than PROWAG.
|
|
|
Corrective Action Required
Storm Profiles: The hydraulic grade line for the design storm event was missing. Ensure the hydraulic grade line for the design storm is at or below the crown of the pipe.
|
|
|
Corrective Action Required
A stormwater calculation sheet was missing. Normally, this is in the form of a table.
|
|
|
Corrective Action Required
Sheet 17: This sheet has numerous issues, including a call-out for a scour basin which does not exist. Although we agree a scour basin, or other energy dissipation measure, be installed to manage the supercritical flow at this location, details of the design must be presented in a clear fashion, and include relevant references on this sheet.
|
|
|
Corrective Action Required
Sheet 17: The 100 year water surface elevation called-out on this sheet does not match what is shown in the stormwater report.
|
|
|
Corrective Action Required
Sheet 17: The MARC Manual recommends either an orifice, perforated riser, or v-notch weir to provide 40 hour extended detention. How will you provide 40 hour extended detention with a single weir opening as shown on this sheet?
|
|
|
Corrective Action Required
Sheet 17: Based on comments related to the stormwater report, no further review will be completed until a revised stormwater report has been submitted and approved. Since it is unclear where and how the emergency spillway will be placed, it is difficult to provide additional comment.
|
|
|
Corrective Action Required
General Comment on Outlet Structure: We will not allow a reference to the structural details such as "See City of Lee's Summit Storm Inlet Standard Detail (STM-2) for Wall Sections, Concrete and Reinforcement". This needs to be a specific design rather than a generic design based on an irrelevant structure.
|
|
|
Corrective Action Required
The rock checks or similar as shown on the esp-construction phase (sheet 3) should be added to the pre-clearing phase (sheet 2), specifically the checks near the lowest point of site discharge.
|
|
|
Corrective Action Required
Has a SWPPP been submitted for this project?
|
|
|
Corrective Action Required
Please see the water line plan review comments. It appears the storm sewer was designed without any regard to the placement of water mains. In general, placement of water mains above storm lines is preferred, and it appears in certain instances this can be achieved.
|
|
|
Corrective Action Required
When determining the hydraulic grade line within the storm lines, please ensure the hydraulic grade line within the detention basin is properly accounted in the calculations.
|
|
|
|
