Lee's Summit

Sanitary sewer easements were not recorded properly. Exhibits and legal descriptions described a temporary construction easement, while the text described a permanent sanitary sewer easement. The City cannot grant a Certificate of Substantial Completion/building permits until suitable public sanitary sewer easements are provided to the City.

The drop across the manhole within the floodplain was installed with a substandard drop.

Sheet 3 of 7: The plans show an 18 inch ductile iron pipe connected to existing City manhole SP-8. The profile view shows this pipe is higher than the crown of the receiving pipe. However, the receiving pipe is 24 inch. The flowline elevations show that the 18 inch ductile iron pipe will be installed below the crown of the receiving pipe. It appears the receiving pipe was drawn in error. In accordance with the Design and Construction Manual, when a smaller sewer joins a large one, the invert of the larger sewer should be lowered sufficiently to maintain the same energy gradient. An approximate method for accomplishing this is to place the 0.8 depth point of both sewers at the same elevation. At an absolute minimum, the crown of the receiving pipe should be at or below the incoming pipe crown.

The above comment will likely require adjustment of the upstream segment up to and including manhole A2.

Please refer to the applicant letter dated Dec. 13, 2018, comment 13. We had requested that a simple calculation be peformed to determine the 100 year water surface elevation in the vicinity of the creek crossing shown on Sheet 4 of 7 (i.e., between manholes A6 and A5). No calculation was provided, nor shown on the plans. There is concern that the manhole is within the channel, especially on the north side since the manhole appears to be shown between the banks of the channel. It is likely this manhole should be moved to the north, outside the channel, and beyond the bank of the channel. At a minimum, however, the 100 year water surface elevation should be calculated, and shown on the plans. Assumptions should consider full build-out conditions for development.

Please refer to the applicant letter dated Dec. 13, 2018, comment 15. Issues with the grading near manhole A7 were discussed. The most recent plan and profile view, however, shows grading in the vicinity of this manhole, with the intent to lower the cover to meet the 15 foot requirement. This grading is going to create a depression in the vicinity of the sanitary sewer line, and form a swale of sorts. The bigger question is "why are you doing any grading at all?". It appears the finish grade over the sanitary sewer will be only slightly greater than 15 feet of cover (i.e., just inches above the requirement). In other words, we are recommending the existing grade, if accurately depicted on these drawings, not be altered in any way.

Concerning the above comment, the 15 foot cover note shown on Sheet 4 of 7 is not scaled properly. As shown, it is depicting approximately 14.5 feet. For your information, 15 feet of cover is measured from the top of pipe, not the flow line of the pipe.

Please refer to the applicant letter dated Dec. 13, 2018, comment 18 and 19. We had requested a detail for the frame and cover, but only received a detail for the cover. We had also requested a detail for the trenching and backfill. A trenching and backfill detail was provided, but it merely shows "bedding", with no explanation or definition, and "backfill", with no explanation or definition.

Please change the title to "Off-Site Sanitary Sewer" or equivalent language, to differentiate between the on-site plans.

Sheet 2 of 7: The stream is not labeled. Please label all streams and stream crossings.

Sheet 2 of 7: Contours should be shown for context. There is no way to determine whether the proposed alignment will be acceptable to Water Utilities without the addition of finish/existing contours.

All Sheets: Where tree clearing or brush clearing is required, specify the width of the clearing to be maintained in perpetuity. Water Utilities requires that any off-site sanitary sewer be accessible, and suitable width within the forested or brushy area will need to be cleared a minimum of 20 feet, centered on the sanitary sewer line.

Sheet 2 of 7: Where is the golf green in relation to the project? Please show the location of the golf green for context.

Provide sufficient notes alerting a contractor to restoration requirements for the area within the golf course impacted by the installation of this sanitary sewer line.

It appears a stream crossing was omitted between manhole A4 and A5. Concrete encasement, restrained joint ductile iron pipe, and sufficient depth of cover is required at this stream crossing.

Sheet 3 of 7: Manhole A5 requires a minimum 0.50 foot drop. Only 0.20 is shown.

Sheet 3 of 7: The location of the manholes shown within the floodplain are not depicted correctly. Since these manhole tops will extend greater than 4 feet above the ground, it is only necessary to provide the following: 1) watertight ring with boltdown cover assembly, 2) neoprene gaskets, and 3) the top should be slightly above finish grade, perhaps 1 foot.

Sheet 3 of 7: The concrete encasement shown at station 1+00 should be extended further to the west to coincide with "bank to bank" encasement of the line. As shown, it is a little short on the west side.

Page 3 of 7: Please indicate where the base flood elevation was obtained.

Sheet 4 of 7: What is the flowline "in" elevation at manhole A8? Please show on the profile view, and ensure there is 0.50 feet minimum drop at this location.

Sheet 4 of 7: What is the calculated 100 year water surface elevation at the creek crossing? The manhole top elevations are likely too low based on the calculated 100 year water surface elevation. It may be better to extend the tops of these manholes above grade, but no greater than 4.0 feet above finish grade. This will enable Water Utilities personnel to quickly locate in the field, and will eliminate the possibility of flooding the manhole.

Sheet 4 of 7: Manhole A7 is shown barely "at grade". Provide perhaps 12 inches above grade to reduce the possibility of the manhole cover being buried.

Sheet 4 of 7: The proposed grade near manhole A7 is shown shaved-down a bit, and it is not clear why this is proposed. Is this proposed to meet the 15 foot depth of cover requirement? If so, then a grading plan will be required. As shown, it is impossible to review what impact this will have on the adjacent grading, stormwater, etc.

Sheet 5 of 7: Where are shallow manholes being proposed? If none, please remove this detail.

Sheet 6 of 7: Where are casing carrier pipes being installed? If none, please remove. If used, then show where they are used. It does not appear, however, any casing carrier pipes will be required or desired on this project.

The standard details for manhole frame and lids was missing, which also shows the lettering "SEWER".

A typical trenching and backfill detail is required. MDNR will reject the plans without it.

General Comment: Additional manholes are required. Although the Design and Construction Manual allows up to 500 feet between runs, Water Utilities has directed Development Services staff to require manholes every 400 feet unless there is compelling reasoning behind the additional length. Please be aware that even if Water Utilities allows this length, MDNR will reject the plans unless they receive a written response from Water Utilities stating the additional length can be maintained by the "continuing authority".