Lee's Summit

The City will require proof of acceptance from MoDOT for any connection to the State highway.

The stormwater report appears to use the incorrect methodology for the detention basin allowable release rate calculation. The City of Lee's Summit utilizes the flat release rate specified in the KCAPWA "Comprehensive Control Strategy", including 40 hour extended detention for the 90 percent mean annual event. Please review and resubmit a report which utilizes this methodolodgy, and please recalculate the allowable release rates.

Please refer to previous applicant letter comment 13. I understand the situation as discussed in your response, but if a walkout is specified, please be aware that a daylight or standard basement is also allowed. If a daylight basement is specified, however, a walkout would not be allowed without a letter from a design professional, but a standard basement would be allowed. If a standard basement is specified, then a daylight or walkout would not be allowed without a letter from a design professional. In other words, specification of the basement type is not necessarily limited to what is shown on the Master Drainage Plan. Please review and revise as appropriate.

Please refer to previous applicant letter comment 3. Although storage was provided for the 100 year event, the 2 and 10 year storage was missing. Please review and revise as appropriate.

On Apr. 28, 2022, a waiver request template was sent to you for the undetained portion of stormwater to the northwest of the project. What is the status of this waiver request? This shall be required prior to formal approval of the plans since grading shall be undertaken in this area and stormwater will be allowed to free-release in this area with no detention.

The City will require proof of acceptance from MoDOT for any connection to the State highway.

The City will require proof of acceptance from MoDOT for any connection to the State highway.

Stormwater report was missing from the submittal. No review was performed on Sheet C503 concerning the detention basin construction elevations, storage volume, discharge rates, etc.. Please submit a stormwater report for this phase of the project.

Is the intent to include the erosion and sediment control plan within this plan set? If so, no land disturbance can be permitted until the street, stormwater and Master Drainage Plan have been submitted. You may wish to consider leaving the mass grading, erosion and sediment control plan out of these plans, as most developers are interested in mass grading and erosion and sediment control prior to approval of the street and stormwater plans. Please review and revise as you feel appropriate.

Sheet C503: In order to facilitate a smooth approval process of the as-built condition of the detention basin, the following items shall be required on this sheet: 1) 2, 10, and 100 year storage. By providing this information on the construction plans, it will be a simple matter at the back end to provide the as-built information by crossing-out and showing the as-built condition. Please revise as appropriate.

Is 4 feet of depth sufficient for the permanent pool? Please be aware that fish cannot survive in this configuration, and it is likely that mosquitoes could become an issue.

KCAPWA requires a minimum of 4.0 feet for a permanent pool depth, plus an allowance for 5 years of siltation. It does not appear any allowance was made for siltation. Please review and revise as appropriate.

All ADA-accessible Ramp Detail Sheets: At all stop-controlled intersections, please show the minimum 5 foot wide ADA-accessible route across the intersection, including the maximum 1.5% slope across the entire route. Please review and update as appropriate.

Please show on the plans where sidewalk and ADA-accessible ramps will be constructed. All ADA-ramps shall be constructed during construction of the improvements shown on these plans, and all sidewalk along unplatted tracts or common area tracts shall also be constructed during construction of the improvements shown on the plans. Please indicate by notes on the plans, preferably on the general layout sheet and the individual plan and profile sheets. All other sidewalk should be noted as "to be constructed by homebuilder" or equivalent language.

Regarding sidewalk notes (above comment), it may be easiest to provide notes in the legend, along with corresponding notes on the plan view. The intent should be to clearly show the contractor and inspector the limits of construction of sidewalk and ADA-accessible ramps. Please review and update as appropriate.

Sheet C410: The detail on the lower right hand side of the sheet shows a straight-in ADA ramp with detectable warning more than 5.0 feet from back of curb. The detectable warning should be skewed at this location so that no more then 5.0 feet between the detectable warning and the back of curb exists. Please revise.

General Note on Master Drainage Plan: All sheets comprising the Master Drainage Plan shall be titled as such. There are sheets related to the Master Drainage Plan that are titled as "Minimum Building Opening", and this is ok but should be prefaced as "Master Drainage Plan". The City also has adopted "Minimum Building Opening Elevation (MBOE)" as the official nomenclature, and this should also be reflected on the sheets comprising the Master Drainage Plan. The reason behind this requirement is that the Master Drainage Plan is used by Development Services permit technicians during plot plan reviews, and it can become confusing on the nomenclature if this is not followed. Please review and revise as appropriate.

The MBOEs for the lots do not necessarily need to be specified for each lot. The City has encountered issues with this requirement in the past, and has now adopted a less stringent requirement for setting MBOEs for lots. In general, the following design philosophy is recognized as acceptable: 1) MBOEs are only required along detention basin tracts or emergency overflow swales where the underground system cannot manage the 100 year event without surcharging (i.e., defined as the HGL being less than 6 inches from the throat of the inlet during the 100 year event assuming pressure flow), 2) where overflow swales are required, the HGL within the overflow swale is generally-calculated as the excess above and beyond what the inlet cannot manage using the criteria specified above in item 1 (i.e., calculation of flow within the overflow swale need not consider a fully-clogged condition, but rather, the incremental flow above and beyond what the underground system cannot manage without surcharging), and 3) any other situation where the design engineer feels that an MBOE is required to protect property from flooding. A minimum freeboard of 2.0 feet is required from he 100 year HGL to the lowest opening in the structure. Please review, analyze, and revise as deemed appropriate.

Regarding the above comment, if the design engineer feels MBOEs are prudent for each lot, that is also acceptable. It is not required, however, and I wanted to make you aware of this design philosophy so that individual homebuilders have options during construction, and individual plot plans are then subsequently reviewed on the basis of "good lot grading practice" (i.e., minimum slope away from building, minimum slope in any direction within the lot, etc.).

Master Drainage Plan: The City is requiring all lots to specify walkout, daylight, or standard basement types for each lot. Please review and revise as appropriate.

Please specify "wet detention" or equivalent language on all sheets where the new detention basin is to be constructed.

All Storm Sheets: Recommend all storm lines be sized for the 100 year event (i.e., pressure flow with the HGL no less than 6 inches from the throat of the inlet). If not, emergency overflow swales shall be designated for each scenario, along with detailing of each swale by sections at appropriate intervals. It would appear the system may already be functioning in this fashion, but unclear unless I review the individual calculation sheets. Recommend showing the HGL for the 100 year event on the profile view. If the 100 year HGL is out of tolerance specified above, recommend upsizing the pipe to manage the 100 year event during pressure flow. Please analyze, review, and revise as appropriate.