Lee's Summit

A note is shown on sheet C.100 stating the existinig outlet structure will remain in place. This contradicts the notes on the plans, which state the outlet structure and pipinig will be removed.

MBOEs are called-out on the grading plan. Since this is not a Master Drainage Plan, shouldn't these be removed? The lots shown in the table relate to Napa Valley 3rd Plat, and unplatted ground to the south. Is there a reason the original MBOEs shown on Napa Valley 3rd Plat be changed? Finally, the unplatted ground should not include MBOEs at this time.

If modifications to the Napa Valley 3rd Plat Master Drainage Plan are sought, then a separate plan set is required. It may be better to remove any references to MBOEs within these plans, especially since the approved Master Drainage Plan shows MBOEs which are higher than proposed in these plans.

Sheet C.200: Features are shown to the south in bold lineweight, even though these are presented elsewhere in the plan set as "future construction for reference only". Please change the lineweight and add notes as appropriate.

Sheet C.301: Please provide a graphical representation (i.e., cross-hatching on the profile view) showing that fill will be placed and compacted for the new storm line, followed by trenching and backfill of the storm line. This is a new requirement in addition to the standard note concerning the placement of fill and compaction in fill areas prior to trenching and backfill of storm lines, sanitary sewer lines, and water lines.

Sheet C.301: Please show the design storm (i.e., 100 year) hydraulic grade line for storm line 1 on the profile view.

The "Macro Storm Water Drainage Study" dated July 8, 2020 (hereinafter referred to as the drainage study) show weir C setup in what appears to be an incorrect configuration. For instance, the setup page appears to show the 10 inch orifice within the baffle as a weir, rather than a culvert/orifice. In addition, the weir shown on the top of the baffle wall appears to be shown as a culvert, when it should be a weir. Even more concerning is the configuration of the weir/orifice geometry in relation to the permanent pool. Since the outlet structure is being placed lower than the permanent pool, it would appear the routing calculations "break down", and once the outlet structure is filled with water, the flow dynamics will not mirror what is shown in the report. At that point (i.e, when the outlet structure is fully-submerged), it would appear the only control structure acting on the outlet structure is the weir structure, above the 10 inch opening. In other words, the routing results appear questionable using this particular geometry.

The drainage study appears to show weir B as the emergency spillway. It appears to have been included in the routing calculations. The emergency spillway should never be included in the routing calculations, unless it is calculated separate from the outlet structure. Flow within the emergency spillway should be calculated separately assuming 100% clogging and zero available storage within the basin.

Sheet C.300: Why is this sheet labeled "Utility Plan"?

Sheet C.300: This sheet appears to be focused on the detention basin, and should be titled appropriately. Since the focus of this sheet is the detention basin, where are the specific labels showing the emergency spillway, and the elevation of the emergency spillway? Why does this emergency spillway slightly differ from the drainage study?

The emergency release structure shown on the inset appears to be calling out instructions as if this were a siphon. It does not appear this design is capable of acting as a siphon. In addition, where is the trenching detail for this pipe, since it will not be acting as a siphon? Are there any plans to prevent the occurence of "piping" around the annulus of the pipe?

Sheet C.300: Section A-A appears to show a 30 inch HDPE pipe, but isn't this a 36 inch HDPE pipe?

Sheet C.300: Where are the calculations for the rip rap at the end of the discharge pipe?

Sheet C.300: The top of the concrete outlet structure shows a four (4) sided weir structure with an elevation set at the emergency spillway elevation. This is not acceptable, unless the primary outlet structure is intended to work in tandem with the earthen emergency spillway. Is this the case? If so, why was this not discussed within the body of the drainage study? Although it is shown within body of the report within a summary table, it is never explicitly discussed this is the case.

The permanent pool elevation is shown at 983.0. The interior baffle wall orifice is shown at an elevation of 981.80. It would appear the permenant pool, therefore, would be 981.80. Without a plan and profile view, however, of the incoming 36 inch pipe, it is impossible to determine what the permanent pool elevation will be. Is the incoming pipe to be placed at 983.0 flowline elevation? Details such as this are critical to a review of these plans.

The emergency discharge pipe shows a valve to be installed on the 8 inch line. Please show on the profile view, in addition to the plan view.

Detention Sheets and Sheet C.200: Please clearly label the 100 year water surface elevation is in relation to the property lines. Ensure there is a minimum of 20 feet between this elevation and any property line. In this instance, it will be acceptable to use the nominal (i.e., fully-functioning) elevation.

Where are the calculations for the 100% clogged, zero available storage? This will need to include calculations showing the maximum water surface elevation, and minimum freeboard of 1.0 feet between this elevation, and the top of the dam.

Please see the KCAPWA requirements for anticlogging measures. 5608.4E(5) and (6). There did not appear to be any anti-clogging measures shown for the outlet structure.