Lee's Summit

As requested in the previous applicant letter, further engineering work was recommended to lessen the depth issues related to the sanitary sewer. Although this was addressed on the connection point to the south of Colbern Rd., it appears no other effort was expended in lessening the impact. I found the following locations where this impact can be lessened by using a different pipe slope, adjusting flowline elevations, or a combination of both. The following are examples: 1) the segment between manhole Z2 and Z1 could be decreased significantly, 2) the segment between the existing manhole being replaced at 16-008 and manhole Z2 could be decreased slightly, recommend no less than 0.40% (0.33% is the minimum required by the Design and Construction Manual), 3) manhole A1 to existing manhole 16-010 (to be replaced) is shown with excessive slope for no apparent reason, and appears slope can be lessened significantly with an outside drop manhole, 4) manhole C1 is deep for no apparent reason. Please revise.

Sheet 660: Flowline in at Z3 has zero fall across the invert. Minimum fall across inverts at this angle is 0.20 feet. Please revise.

Sheet 656: It does not appear sufficient fall was provided across the invert at manhole 16-010. Minimum slope for this angle of entry and exit is 0.50 feet. Please revise.

Please revise the Design Criteria Modification Request (i.e., the waiver) as appropriate after making revisions. Please ensure the waiver request is submitted as one (1) pdf document which includes 1) the form, 2) the summary sheet, and 3) the exhibit.

Sheet 652: Please label each manhole on the general overview sheet. Many manhole labels were missing for existing manholes to be removed and replaced, and makes the interpretation in the field difficult for the contractor and the inspector.

Stub Locations: There are numerous references to marking the end of the line for future location. Tracer wire and box will be required as per the City of Lee's Summit standard detail. Recommend the plan view of the sanitary stubs be revised to reference the standard detail for tracer wire and other design requirements for a wye connection (i.e., SAN-1).

Sheet C664 was shown in the previous submittal with the forcemain outside the limits of the dam. A review of Sheet C663, however, appears to show the forcemain is still within the limits of the dam. The forcemain must be outside the limits of the dam, since it will present a conduit for potential failure, as well as the possibility of a line break and subsequent dam failure. Please review and revise as appropriate, and ensure the forcemain is outside the limits of the dam.

The sanitary sewer manholes that exceed 20 feet of depth should be upgraded to 5 foot inside diameter. Many are already shown as 5 foot inner diameter manholes, with the exception of Z1, Z2, 16-008, 16-010, 16-009, and A8. Please revise plans to show 5 foot inside diameter sanitary sewer manholes for all sanitary sewer manholes greater than 20 feet in depth.

Manhole A8 is shown with excessive depth for no apparent reason. It was also not included in the waiver exhibit. Was there a reason for the excessive depth on the south side of Colbern Rd.? If not, please raise the manhole.

It does not appear sufficient effort was expended to lessen the depth of sanitary sewer lines throughout the project. Where allowed, please raise manholes to lessen the impact of deep sanitary sewers for this project. There appear to be several ways to minimize the depth issues, one of which was described in the above comment. There also appear to be methods to raise the manholes at the Douglas St. crossing by a measurable amount. Every foot will help, as these lines will be extremely difficult to maintain as shown. Please thoroughly evaluate and revise. At this time, staff will not support a waiver to the 20 foot maximum depth rule unless there has been additional effort to minimize the excessive depth issues.

Please refer to comment #21 in the previous applicant letter. Connection at Sta. 10+09.53 is not DIP to HDPE connection. Please specify electrofusion coupling for HDPE to HDPE connection. Please revise as appropriate.

The waiver request was missing the standard template with Water Utilities listed as a reviewer. I have attached the template for your use, and this form includes the signature for Jeff Thorn, Deputy Director of Water Utilities. Please complete the form with Water Utilities listed as a reviewer. In addition, this form also lists Sue Pyles which was also missing. Please include her in the template form.

The waiver request was missing an exhibit showing in general where the waiver is being requested (i.e., a plan view with labels or other methods to show the typical depths from finish grade to flowline along selected intervals along the sanitary sewer line would suffice). Please provide an exhibit showing where the waiver is being sought.

Off-site sanitary sewer easements shall be required prior to formal approval of the plans. The City desires these easements to be exclusive to sanitary sewer, and the City has a standard template for language related to this easement. Please provide exclusive sanitary sewer easements for the project.

Please refer to the separate pdf markup of the plans for specific comments related to the sanitary sewer and forcemain. This markup shall be transmitted separately.

A trenching and backfill detail was missing from the plans. Please ensure the new standard of 12 inches aggregate is shown over the top of pipe.

The geometry of the forcemain appears to bisect the dam for the retention basin which is not acceptable. Please select a new route which does not impact the dam during a malfunction of the forcemain or future maintenance of the forcemain.

A separate meeting via Zoom will be setup soon to discuss the water main and the Colbern Rd. CIP project. We would recommend these plans be added to the agenda for discussion due to the amount of comments related to the sanitary sewer plans.