| Review Type |
Outcome |
Est. Completion Date |
Completed |
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Engineer Review - Grading
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Approved with Conditions
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05/14/2025
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05/05/2025
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Gene Williams, P.E.
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DE Engineers Estimate
Corrective Action Required
The Engineer’s Estimate of Probable Construction Costs has been accepted for this project, and the Engineering Plan Review and Inspection Fee (which is calculated as 3% of the total infrastructure cost plus a water test inspection fee(s)), and the water tap and meter setup fee have been included. These must be paid prior to the issuance of an infrastructure permit and/or the final processing of a building permit. $21,004.62
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DE Commercial Detention Basin
Corrective Action Required
The applicant shall submit and the City shall accept an “As-built / As-graded” retention basin plan prior to issuance of any Certificate of Substantial Completion for the proposed development.
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DE Contact Field Eng. Inspector
Corrective Action Required
Prior to the commencement of any construction activities, the Contractor shall contact Field Engineering Inspections at (816) 969-1200 to schedule a project coordination meeting with the assigned Field Engineering Inspector.
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Engineer Review - Grading
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Corrections
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03/21/2025
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03/13/2025
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Gene Williams, P.E.
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Miscellaneous Correction
Corrective Action Required
Missing detailed plan and profile view of the storm line and structure located at the extreme southeast corner of the retention basin.
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Miscellaneous Correction
Corrective Action Required
Signed and sealed estimate required prior to formal approval.
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Engineering Review
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Approved
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03/07/2025
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03/06/2025
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Gene Williams, P.E.
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Tree clearing only
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Engineering Review
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Rejected
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03/07/2025
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02/28/2025
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Gene Williams, P.E.
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Tree clearing only
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Engineer Review - Grading
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Corrections
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02/28/2025
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02/20/2025
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Gene Williams, P.E.
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Miscellaneous Correction
Dam height for purposes of applicability to TR-60 is measured from the emergency spillway to the lowest point on the downstream face of the dam at the creek flowline. Discuss within revised stormwater report. Correction required.
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Miscellaneous Correction
Corrective Action Required
Dam and retention basin is incomplete. As discussed during the in-person meeting, the dam design shall include cross-sections of the dam, elevation views, foundation details, dimensions and material specifications, materials used in the dam including amount of lifts, types of materials used in each lift, clay core, drainage blankets, etc. Just because the dam may or may not be subject to TR-60 design requirements does not negate the need for a detailed design. Correcton required.
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Miscellaneous Correction
Sheet C.300: RCP outlet pipes from the retention basin are shown with excessive slope. Is there a reason for the excessive slope? Correction required.
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Miscellaneous Correction
Sheet C.201: The grading behind (i.e., east property line) 1111 SW Mission Pl. has reverted back to what we commented upon during the Preliminary Development Plan as being not ideal. You changed the grading plan during that process, but it has now reverted back to what was originally shown as not ideal. You are showing the creation of a small swale that directs stormwater towards this lot. It appears this was done because you ran out of space for the detention basin? Correction required if applicable.
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Miscellaneous Correction
We need more than a note on the plans about the installation of skimmer in the detention basin. Complete details as normally required on all other previous projects shall be provided. Correction required.
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Miscellaneous Correction
Corrective Action Required
Plunge pool using rip rap, or other high discharge method of energy dissipation is warranted for the detention basin storage. Simple rip rap for three (3) RCP pipes is not going to be an acceptable method of energy dissipation. See comments below concerning the rip rap calculations, which appear erroneous. For large retention/detention basins, this has been an ongoing requirement. Recommend visiting Cobey Creek and examining the energy dissipation measures installed at that location, or the backside of the dam at Discovery Park which incorporates a rip rap-lined plunge pool. Correction required.
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Miscellaneous Correction
Details are now provided on the retaining walls, but there will be considerable banter especially on the higher walls. This was not shown on the plan view, but rather, a simple line. The banter will encroach upon the limits of the curb inlets shown on top of the retaining wall, as well as the storm line along the west side of the project parallel to the retaining wall. It is possible this banter will encroach-upon other features. The retaining wall viewed in plan view cannot be represented by a single line. Correction required.
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Miscellaneous Correction
Corrective Action Required
A geotechnical report shall be prepared to support the retaining wall design, dam design, borrow areas, foundation of the dam including any test borings, soil conditions, compaction requirements, and third party testing required duriing construction. Correction required.
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Miscellaneous Correction
Sheet C.201: Need additional contours along the southwest portioin of the detention basin where contours are unlabeled to evaluate design. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Emergency spillway is shown with potential discharge over the primary outlet works. This does not appear to meet any design standards for dams. I do not agree the location shown is the best location for an emergency spillway, and it would appear other alternatives are available. Be aware that earthen emergency spillways are not the only method to provide emergency spillway for a retention basin. Correction required.
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Miscellaneous Correction
All storm lines shall be private, and labeled on the profile view with the word "PRIVATE". Correction required.
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Miscellaneous Correction
Sheet C.300: Elevation of proposed ground in relation to the outlet structure on the profile view appears incorrect based on your elevations shown. Correction required.
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Miscellaneous Correction
Outlet control structure details did not show materials of construction, thickness, reinforcing steel, etc. There were notes, but it should be shown on the drawing. Correction required.
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Miscellaneous Correction
You may need a better solution to drain the pond for the water quality event. The small orifice does not contain any detail. Simple notes with a phone number are not sufficient. If this method is desired, provide more detail in the form of material submittals within the plans. Correction required.
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Miscellaneous Correction
See Design and Construction Manual for permanent retention basins with a permanent pool. I am not convinced the method you are showing will suffice for such a large retention basin. Evaluation and correction may be required.
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Miscellaneous Correction
Corrective Action Required
Where are the steps for the outlet structures? Notes are not sufficient (i.e., "steps at 16 inch o.c." is not sufficient. We need to know where the steps are located in graphic format, not a note. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.211 shows a steel detail (i.e., Wall Corner Detail) which is illegible. Correction required.
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Miscellaneous Correction
Sheet C.211 still shows 60 inch HDPE pipe on the discharge side rather than RCP. Correction required.
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Miscellaneous Correction
Corrective Action Required
It appears the majority of the dam grading on the front side has been steepened to 2:1 slope, which is not going to be acceptable without a geotechnical study and report. It appears this was changed without any discussion, notation, or explanation. Correction required.
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Miscellaneous Correction
Did you subtract the storage from the permanent pool from the total storage? If not, that needs to happen. Correction may be required if you did not subtact the permanent pool storage.
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Miscellaneous Correction
Rename the plans to Retention Basin, Mass Grading, and Erosion and Sediment Control Plans, or equivalent language. Ensure "Retention Basin" is included in the title.
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Miscellaneous Correction
Cursury calculations showed approximately 850,000 cubic feet of storage for 6 feet of depth to the 100 year design HGL. This does not appear to match what is shown on the plans (i.e., 1,300,000 cubic feet). Evaluate and correct if appropriate.
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Miscellaneous Correction
Dam height is measured from top of dam to the lowest point of the receiving creek bed. Since this is higher than 10.0 feet, the dam is subject to TR-60 design requirements. Since the dam is subject to TR-60 requirements with additional freeboard from the 100 year clogged HGL to the top of dam, additional studies, width of the flat spot on the dam, slopes of the dam, and other design criteria listed in TR-60 are required unless the dam height is less than 10 feet. Correction required.
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Miscellaneous Correction
Stormwater study should be revised to include the TR-60 design requirements. Correction required.
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Miscellaneous Correction
Sheet C.300: Normal drafting practice is to specifically detail the number of pipes in the profile view as well as the plan view? Profile view only shows one (1) pipe. A note should be provided showing three (3) pipes. Correction required.
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Miscellaneous Correction
Sheet C.300: Outlet pipes should be RCP rather than HDPE due to the size. Correction required.
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Miscellaneous Correction
Sheet C.201: The grading behind (i.e., east property line) 1111 SW Mission Pl. has reverted back to what we commented upon during the Preliminary Development Plan as being not ideal. You changed the grading plan during that process, but it has now reverted back to what was originally shown as not ideal. You are showing the creation of a small swale that directs stormwater towards this lot. It appears this was done because you ran out of space for the detention basin? Correction required if applicable.
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Miscellaneous Correction
We need more than a note on the plans about the installation of skimmer in the detention basin. Complete details as normally required on all other previous projects shall be provided. Correction required.
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Miscellaneous Correction
Corrective Action Required
Plunge pool or other high discharge method of energy dissipation is warranted for the detention basin storage. Simple rip rap for three (3) RCP pipes is not going to be an acceptable method of energy dissipation. See subsequent comments in this letter concerning the design discharge used in your calculations which appear incorrect. Complete design with details is required. Correction required.
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Miscellaneous Correction
We will need additional design details on the retaining walls. As shown in your typical section view, it would appear geogrid will be extended into the large stormwater pipe along the west side of the project, which would be a problem. Additional dimension callouts on the typical section view are required to assess such items as: 1) whether the shared-use path is within the limits of the retaining wall foundation, 2) whether the retaining wall foundation is part of the dam's zone of influence, 3) whether the large stormwater pipe will be within the geogrid, or worst case if the banter causes the stormwater line to be within the retaining wall itself. Correction required.
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Miscellaneous Correction
Sheet C.201: Need additional contours along the southwest portioin of the detention basin where contours are unlabeled to evaluate design. Correction required.
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Miscellaneous Correction
All storm lines shall be private, and labeled on the profile view with the word "PRIVATE". Correction required.
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Miscellaneous Correction
Sheet C.300: Elevation of proposed ground in relation to the outlet structure on the profile view appears incorrect based on your elevations shown. Correction required.
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Miscellaneous Correction
Outlet control structure details did not show materials of construction, thickness, reinforcing steel, etc. There were notes, but it should be shown on the drawing. Correction required.
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Miscellaneous Correction
You may need a better solution to drain the pond for the water quality event. The small orifice does not contain any detail. Simple notes with a phone number are not sufficient. If this method is desired, provide more detail in the form of material submittals within the plans. Correction required.
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Miscellaneous Correction
See Design and Construction Manual for permanent retention basins with a permanent pool. I am not convinced the method you are showing will suffice for such a large retention basin. Evaluation and correction may be required.
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Miscellaneous Correction
Corrective Action Required
Where are the steps for the outlet structures? Correction required.
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Miscellaneous Correction
Where are the details for the "manway" on the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Have you received any documentation from the USACE about jurisdictional waters? We will need to see this prior to formal approval. Informational comment.
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Miscellaneous Correction
All three (3) details need to be provided for each outlet structure. The note stating that "only one shall incorporate the orifice" is confusing to those in the field. Show all three (3) outlet structures to ensure there is no confusion in the field. Correction required.
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Miscellaneous Correction
Did you subtract the storage from the permanent pool from the total storage? If not, that needs to happen. Correction may be required if you did not subtact the permanent pool storage.
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Miscellaneous Correction
Rename the plans to Retention Basin, Mass Grading, and Erosion and Sediment Control Plans, or equivalent language. Ensure "Retention Basin" is included in the title.
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Miscellaneous Correction
Corrective Action Required
Final review of cost estimate to be completed at a later date, after review of final plans. Informational comment.
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Miscellaneous Correction
Cursury calculations showed approximately 850,000 cubic feet of storage for 6 feet of depth to the 100 year design HGL. This does not appear to match what is shown on the plans (i.e., 1,300,000 cubic feet). Evaluate and correct if appropriate.
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Miscellaneous Correction
Corrective Action Required
You are showiing the creek entering the basin on the southeast corner without any control structures such as a large field inlet or other structure, channels, or other methods to achieve a smooth transition to the retention basin. As shown, severe erosion will take place on the 33.3% slope, and backcutting within the first year will erode the channel back to the property line or over the property line. A method to control the incoming drainage is required. Corrections required.
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Miscellaneous Correction
Corrective Action Required
Sediment forebay required for a retention basin with permanent pool. See Design and Construction Manual for specific details. Correction required.
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Miscellaneous Correction
Corrective Action Required
5608.5A4 of the Design and Construction Manual states that side slopes within wet detention basins (i.e., retention basins) shall conform to the natural grade as closely as possible, but in no case shall be greater than 3:1. If greater than 3:1 slope, it would only be supported with additiional safety measures to prevent drowinng, additional erosion control, and a geotechnical report supporting the waiver. If the area of excessive slope is within the zone of influence of dam, shared use path, or retaining wall, the geotechnical report would be required to address. Informational comment.
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Miscellaneous Correction
Corrective Action Required
It appears the majority of the dam is being constructed on Park property. Parks will not allow a private dam on their property. All dam and associated outlet works and dissipation measures shall be contained on-site unless a suitable agreement is developed. Correction required.
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Miscellaneous Correction
Corrective Action Required
Looking at the grading along the proposed retaining wall, it appears a portion of the retaining wall is part of the dam. Geotechnical report should address this aspect. Informational comment.
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Miscellaneous Correction
Corrective Action Required
It appears additional grading information in the form of elevation callouts is needed on the north side, at the intersection of the two retaining walls. This area appears to be part of he dam structure, and if so, shall be subject to all ldesign and construction requirements. Correction required.
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Miscellaneous Correction
Corrective Action Required
It appears the stormwater detention design parameters in almost all cases were pushed to the limit on freeboard and storage requirements. Suggest increasing the freeboard and storage to allow for tolerance. Correction required.
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Miscellaneous Correction
Corrective Action Required
What is the plan for diverting stormwater during construction of the dam? A phasing plan should be developed within the plan set showing how stormwater will be managed while constructing the dam. It shall be capable of managing the 100 year event. Correction required.
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Miscellaneous Correction
Corrective Action Required
A storm pipe exiting an existing detention basin to the north is not shown, and it is not clear how this storm line will be incorporated into the overall drainage design for the site. This is the storm line running from the existing detention basin and exiting to the southwest towards the residential subdivision. Correction required.
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Miscellaneous Correction
Corrective Action Required
Contours shown in the vicinity of the ADA ramp near the emergency spillway do not make sense. For instance, you are showing the top of dam at 1004.5 at a point, but the contours indicate the elevation is closer to 1003.5. In addition, a contour is shown at 1004, but inexplicably the contour changes to 1003 with no transition (i.e., the line "splits" and what was once 1004 is now an impossible 1003). Correction required.
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Miscellaneous Correction
Corrective Action Required
You appear to be missing contours in the vicinity of the ADA-accessbile ramp near the emergency spillway. As shown, contours end abruptly, with no transition shown. As previously commented, all elements of the dam shall be thoroughly detailed, including any ancilary features such as an ADA-ramp that has been incorporated into the dam. Correction required.
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Miscellaneous Correction
Corrective Action Required
GIS records indicate there may be a storm line entering from the south. It appears to be an 18 inch private storm line draining the existing detention basin to the south. Show its location, and how the stormwater flows will be directed into the basin. This flow should be directed underground to eliminate backcutting that will occur if left to sheet flow over a 33% slope. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.211: The detail for the unnamed inset (i.e., the detail showing the trash rack for the water quality orifices) is illegible. It is also lacking the definition of A, B, and C, and the orifice diameter. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.211: Section view in lower right hand corner of this sheet is showing 3:1 slopes througout the entire dam face. This does not match your plans. Geotechnical report and study should be used to determine this slope based on the materials and site conditions. Correction required.
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Miscellaneous Correction
Corrective Action Required
Rip rap design is based on 158 cfs as shown on Sheet C.211. Stormwater report is showing a significantly different design discharge for the retention basin. Correction required.
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Miscellaneous Correction
Corrective Action Required
According to the incomplete grading details on the backside of the dam near the discharge point, it would appear you are proposing to match existing grades and existing foliage such as trees. Is this good engineering practice to leave tree roots within a dam? It has been my experience leaving tree roots and trees within a dam will lead to long-term issues such as piping. Evaluation and correction required.
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Miscellaneous Correction
Corrective Action Required
A SWPPP is required prior to formal approval of the project. Informational comment.
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Miscellaneous Correction
Corrective Action Required
Retaining wall is shown immediately abutting the 10 foot shared-use path along the north side of the pond. Typical section view of the retaining wall appears to show an unspecified flat area of unspecified distance in front of the first segmental course. It would appear additional distance was not accounted-for in the distance needed to install the 10 foot shared-use path. Correction required.
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Miscellaneous Correction
Corrective Action Required
You are showing the ADA-ramp connecting to the Park property, but the ADA-ramp is shown with a retaining wall which is part of the dam. As previously commented, the dam should be independent of any structure(s), and retaining walls constructed within the limits of the dam shall require analysis. Correction required.
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Miscellaneous Correction
Corrective Action Required
Reviewing the existing grades along the southwest corner of the retaining wall intersection (i.e., the intersection of the north/south retaining wall and the east/west retaining wall), the retaining wall and associated grading to the west of the retaining wall appears to be part of the dam embankment, and thus part of the overall design of the dam. As such, this shall be addressed in the geotechnical study and report. Correction required.
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Miscellaneous Correction
Corrective Action Required
Recommend a meeting to discuss. Plans are incomplete. Informational comment.
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Engineer Review - Grading
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Corrections
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01/27/2025
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01/17/2025
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Gene Williams, P.E.
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Miscellaneous Correction
Corrective Action Required
Dam height is measured from top of dam to the lowest point of the receiving creek bed. Since this is higher than 10.0 feet, the dam is subject to TR-60 design requirements. Since the dam is subject to TR-60 requirements with additional freeboard from the 100 year clogged HGL to the top of dam, additional studies, width of the flat spot on the dam, slopes of the dam, and other design criteria listed in TR-60 are required unless the dam height is less than 10 feet. Correction required.
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Miscellaneous Correction
Corrective Action Required
Dam height is measured from top of dam to the lowest point of the receiving creek bed. Since this is higher than 10.0 feet, the dam is subject to TR-60 design requirements. Since the dam is subject to TR-60 requirements with additional freeboard from the 100 year clogged HGL to the top of dam, additional studies, width of the flat spot on the dam, slopes of the dam, and other design criteria listed in TR-60 are required unless the dam height is less than 10 feet. Correction required.
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Miscellaneous Correction
Corrective Action Required
Stormwater study should be revised to include the TR-60 design requirements. Correction required.
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Miscellaneous Correction
Corrective Action Required
Stormwater study should be revised to include the TR-60 design requirements. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Normal drafting practice is to specifically detail the number of pipes in the profile view as well as the plan view? Profile view only shows one (1) pipe. A note should be provided showing three (3) pipes. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Normal drafting practice is to specifically detail the number of pipes in the profile view as well as the plan view? Profile view only shows one (1) pipe. A note should be provided showing three (3) pipes. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Outlet pipes should be RCP rather than HDPE due to the size. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Outlet pipes should be RCP rather than HDPE due to the size. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: The grading behind (i.e., east property line) 1111 SW Mission Pl. has reverted back to what we commented upon during the Preliminary Development Plan as being not ideal. You changed the grading plan during that process, but it has now reverted back to what was originally shown as not ideal. You are showing the creation of a small swale that directs stormwater towards this lot. It appears this was done because you ran out of space for the detention basin? Correction required if applicable.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: The grading behind (i.e., east property line) 1111 SW Mission Pl. has reverted back to what we commented upon during the Preliminary Development Plan as being not ideal. You changed the grading plan during that process, but it has now reverted back to what was originally shown as not ideal. You are showing the creation of a small swale that directs stormwater towards this lot. It appears this was done because you ran out of space for the detention basin? Correction required if applicable.
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Miscellaneous Correction
Corrective Action Required
We need more than a note on the plans about the installation of skimmer in the detention basin. Complete details as normally required on all other previous projects shall be provided. Correction required.
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Miscellaneous Correction
Corrective Action Required
We need more than a note on the plans about the installation of skimmer in the detention basin. Complete details as normally required on all other previous projects shall be provided. Correction required.
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Miscellaneous Correction
Corrective Action Required
Plunge pool or other high discharge method of energy dissipation is warranted for the detention basin storage. Simple rip rap for three (3) RCP pipes is not going to be an acceptable method of energy dissipation. Complete design with details is required. Correction required.
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Miscellaneous Correction
Corrective Action Required
Plunge pool or other high discharge method of energy dissipation is warranted for the detention basin storage. Simple rip rap for three (3) RCP pipes is not going to be an acceptable method of energy dissipation. Complete design with details is required. Correction required.
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Miscellaneous Correction
Corrective Action Required
Details missing on retaining walls. Complete design information required, including plan and profile views. Correction required.
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Miscellaneous Correction
Corrective Action Required
Details missing on retaining walls. Complete design information required, including plan and profile views. Correction required.
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Miscellaneous Correction
Corrective Action Required
Dam design is incomplete. It shall include plan and profile views, materials and compaction specifications, drain to empty the reservoir within 72 hours, and all other information required under TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
Dam design is incomplete. It shall include plan and profile views, materials and compaction specifications, drain to empty the reservoir within 72 hours, and all other information required under TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Need additional contours along the southwest portioin of the detention basin where contours are unlabeled to evaluate design. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Need additional contours along the southwest portioin of the detention basin where contours are unlabeled to evaluate design. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Emergency spillway is shown over the primary outlet works. This does not appear to meet any design standards for dams, including TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Emergency spillway is shown over the primary outlet works. This does not appear to meet any design standards for dams, including TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
All storm lines shall be private, and labeled on the profile view with the word "PRIVATE". Correction required.
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Miscellaneous Correction
Corrective Action Required
All storm lines shall be private, and labeled on the profile view with the word "PRIVATE". Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Elevation of proposed ground in relation to the outlet structure on the profile view appears incorrect based on your elevations shown. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Elevation of proposed ground in relation to the outlet structure on the profile view appears incorrect based on your elevations shown. Correction required.
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Miscellaneous Correction
Corrective Action Required
Outlet control structure details did not show materials of construction, thickness, reinforcing steel, etc. There were notes, but it should be shown on the drawing. Correction required.
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Miscellaneous Correction
Corrective Action Required
Outlet control structure details did not show materials of construction, thickness, reinforcing steel, etc. There were notes, but it should be shown on the drawing. Correction required.
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Miscellaneous Correction
Corrective Action Required
You may need a better solution to drain the pond for the water quality event. The small orifice does not contain any detail. Simple notes with a phone number are not sufficient. If this method is desired, provide more detail in the form of material submittals within the plans. Correction required.
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Miscellaneous Correction
Corrective Action Required
You may need a better solution to drain the pond for the water quality event. The small orifice does not contain any detail. Simple notes with a phone number are not sufficient. If this method is desired, provide more detail in the form of material submittals within the plans. Correction required.
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Miscellaneous Correction
Corrective Action Required
See Design and Construction Manual for permanent retention basins with a permanent pool. I am not convinced the method you are showing will suffice for such a large retention basin. Evaluation and correction may be required.
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Miscellaneous Correction
Corrective Action Required
See Design and Construction Manual for permanent retention basins with a permanent pool. I am not convinced the method you are showing will suffice for such a large retention basin. Evaluation and correction may be required.
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Miscellaneous Correction
Corrective Action Required
Where are the steps for the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Where are the steps for the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Where are the details for the "manway" on the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Where are the details for the "manway" on the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Have you received any documentation from the USACE about jurisdictional waters? We will need to see this prior to formal approval. Informational comment.
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Miscellaneous Correction
Corrective Action Required
Have you received any documentation from the USACE about jurisdictional waters? We will need to see this prior to formal approval. Informational comment.
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Miscellaneous Correction
Corrective Action Required
All three (3) details need to be provided for each outlet structure. The note stating that "only one shall incorporate the orifice" is confusing to those in the field. Show all three (3) outlet structures to ensure there is no confusion in the field. Correction required.
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Miscellaneous Correction
Corrective Action Required
All three (3) details need to be provided for each outlet structure. The note stating that "only one shall incorporate the orifice" is confusing to those in the field. Show all three (3) outlet structures to ensure there is no confusion in the field. Correction required.
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Miscellaneous Correction
Corrective Action Required
Did you subtract the storage from the permanent pool from the total storage? If not, that needs to happen. Correction may be required if you did not subtact the permanent pool storage.
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Miscellaneous Correction
Corrective Action Required
Did you subtract the storage from the permanent pool from the total storage? If not, that needs to happen. Correction may be required if you did not subtact the permanent pool storage.
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Miscellaneous Correction
Corrective Action Required
Rename the plans to Retention Basin, Mass Grading, and Erosion and Sediment Control Plans, or equivalent language. Ensure "Retention Basin" is included in the title.
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Miscellaneous Correction
Corrective Action Required
Rename the plans to Retention Basin, Mass Grading, and Erosion and Sediment Control Plans, or equivalent language. Ensure "Retention Basin" is included in the title.
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Miscellaneous Correction
Corrective Action Required
Final review of cost estimate to be completed at a later date, after review of final plans. Informational comment.
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Miscellaneous Correction
Corrective Action Required
Final review of cost estimate to be completed at a later date, after review of final plans. Informational comment.
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Miscellaneous Correction
Corrective Action Required
Cursury calculations showed approximately 850,000 cubic feet of storage for 6 feet of depth to the 100 year design HGL. This does not appear to match what is shown on the plans (i.e., 1,300,000 cubic feet). Evaluate and correct if appropriate.
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Miscellaneous Correction
Corrective Action Required
Cursury calculations showed approximately 850,000 cubic feet of storage for 6 feet of depth to the 100 year design HGL. This does not appear to match what is shown on the plans (i.e., 1,300,000 cubic feet). Evaluate and correct if appropriate.
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Engineer Review - Grading
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Corrections
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12/02/2024
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12/03/2024
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Gene Williams, P.E.
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Miscellaneous Correction
Corrective Action Required
Dam height is measured from top of dam to the lowest point of the receiving creek bed. Since this is higher than 10.0 feet, the dam is subject to TR-60 design requirements. Since the dam is subject to TR-60 requirements with additional freeboard from the 100 year clogged HGL to the top of dam, additional studies, width of the flat spot on the dam, slopes of the dam, and other design criteria listed in TR-60 are required unless the dam height is less than 10 feet. Correction required.
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Miscellaneous Correction
Corrective Action Required
Stormwater study should be revised to include the TR-60 design requirements. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Normal drafting practice is to specifically detail the number of pipes in the profile view as well as the plan view? Profile view only shows one (1) pipe. A note should be provided showing three (3) pipes. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Outlet pipes should be RCP rather than HDPE due to the size. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: The grading behind (i.e., east property line) 1111 SW Mission Pl. has reverted back to what we commented upon during the Preliminary Development Plan as being not ideal. You changed the grading plan during that process, but it has now reverted back to what was originally shown as not ideal. You are showing the creation of a small swale that directs stormwater towards this lot. It appears this was done because you ran out of space for the detention basin? Correction required if applicable.
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Miscellaneous Correction
Corrective Action Required
We need more than a note on the plans about the installation of skimmer in the detention basin. Complete details as normally required on all other previous projects shall be provided. Correction required.
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Miscellaneous Correction
Corrective Action Required
Plunge pool or other high discharge method of energy dissipation is warranted for the detention basin storage. Simple rip rap for three (3) RCP pipes is not going to be an acceptable method of energy dissipation. Complete design with details is required. Correction required.
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Miscellaneous Correction
Corrective Action Required
Details missing on retaining walls. Complete design information required, including plan and profile views. Correction required.
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Miscellaneous Correction
Corrective Action Required
Dam design is incomplete. It shall include plan and profile views, materials and compaction specifications, drain to empty the reservoir within 72 hours, and all other information required under TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Need additional contours along the southwest portioin of the detention basin where contours are unlabeled to evaluate design. Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.201: Emergency spillway is shown over the primary outlet works. This does not appear to meet any design standards for dams, including TR-60. Correction required.
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Miscellaneous Correction
Corrective Action Required
All storm lines shall be private, and labeled on the profile view with the word "PRIVATE". Correction required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.300: Elevation of proposed ground in relation to the outlet structure on the profile view appears incorrect based on your elevations shown. Correction required.
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Miscellaneous Correction
Corrective Action Required
Outlet control structure details did not show materials of construction, thickness, reinforcing steel, etc. There were notes, but it should be shown on the drawing. Correction required.
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Miscellaneous Correction
Corrective Action Required
You may need a better solution to drain the pond for the water quality event. The small orifice does not contain any detail. Simple notes with a phone number are not sufficient. If this method is desired, provide more detail in the form of material submittals within the plans. Correction required.
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Miscellaneous Correction
Corrective Action Required
See Design and Construction Manual for permanent retention basins with a permanent pool. I am not convinced the method you are showing will suffice for such a large retention basin. Evaluation and correction may be required.
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Miscellaneous Correction
Corrective Action Required
Where are the steps for the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Where are the details for the "manway" on the outlet structures? Correction required.
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Miscellaneous Correction
Corrective Action Required
Have you received any documentation from the USACE about jurisdictional waters? We will need to see this prior to formal approval. Informational comment.
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Miscellaneous Correction
Corrective Action Required
All three (3) details need to be provided for each outlet structure. The note stating that "only one shall incorporate the orifice" is confusing to those in the field. Show all three (3) outlet structures to ensure there is no confusion in the field. Correction required.
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Miscellaneous Correction
Corrective Action Required
Did you subtract the storage from the permanent pool from the total storage? If not, that needs to happen. Correction may be required if you did not subtact the permanent pool storage.
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Miscellaneous Correction
Corrective Action Required
Rename the plans to Retention Basin, Mass Grading, and Erosion and Sediment Control Plans, or equivalent language. Ensure "Retention Basin" is included in the title.
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Miscellaneous Correction
Corrective Action Required
Final review of cost estimate to be completed at a later date, after review of final plans. Informational comment.
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Miscellaneous Correction
Corrective Action Required
Cursury calculations showed approximately 850,000 cubic feet of storage for 6 feet of depth to the 100 year design HGL. This does not appear to match what is shown on the plans (i.e., 1,300,000 cubic feet). Evaluate and correct if appropriate.
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Engineer Review - Grading
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Corrections
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10/21/2024
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10/17/2024
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Gene Williams, P.E.
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Miscellaneous Correction
Corrective Action Required
Plans are incomplete in terms of identification and design of the sediment basin. Are you proposing the detention basin to act as a sediment basin? Where is the outlet structure? Where is the emergency spillway? Correction required.
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Miscellaneous Correction
Corrective Action Required
100 year clogged/zero available storage condition shall be shown on the plan view(s) along with numeric callout. Minimum of 20 feet setback required from any property line or building. Correction required.
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Miscellaneous Correction
Corrective Action Required
Stormwater report: Grading plan for the detention basin in the appendix does not match the grading plan shown in the plan set on Sheet C.200. No further review of stormwater report or the stormwater detention basin performed.
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Miscellaneous Correction
Corrective Action Required
Sheet C.200: This grading plan is showing the sheetflow discharge of stormwater from the dam onto 1111 SW Mission Place, which we are showing is not currently happening. According to LIDAR data within the GIS, I am showing only 1109 SW Mission Place is currently being affected by stormwater flow within the channel. Drainage swale along the dam should be modified to remove any sheet flow from the dam onto 1111 SW Mission Place, unless a suitable legal agreement is made between the lot owner and the developer. Correction required.
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Miscellaneous Correction
Corrective Action Required
It appers the top of dam width is only 2.5 feet according to Sheet C.200. This is too narrow to provide access to the facility, and is too narrow to provide stability to the top of dam. Minimum width for the top of the dam should be at least wide enough to drive maintenance equipment (e.g., 6 feet?). Correction required.
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Miscellaneous Correction
Corrective Action Required
The grading plan for the detention basin shown in the drainage report differs from what is shown on Sheet C.200. According to the grading plan shown in the appendix of the stormwater report, stormwater from the embankment will impact the residential lots to the west even greater than already shown on Sheet C.200, in particular, 1111 SW Mission Place. Correction required.
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Miscellaneous Correction
Corrective Action Required
Based on a cursury review, it would appear the storage of the detention basin will be too small to manage the 100 year event after moving the basin further to the east to address the above comments, and widening the top of the dam to accommodate access and to provide a stable top of dam. It is likely portions of the basin will need to be constructed with vertical sides (i.e., retaining walls) to accommodate the needed storage. Corrections required.
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Miscellaneous Correction
Corrective Action Required
Sheet C.200: Scale in upper right hand corner appears in error. Correction required.
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Miscellaneous Correction
Corrective Action Required
No further review of Sheet C.200 possible due to scale error (see above). Correction required.
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Miscellaneous Correction
Corrective Action Required
It is questionable whether grading shown on the corners of the detention basin can be achieved (i.e., squared-off rather than rounded). Correction required.
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Miscellaneous Correction
Corrective Action Required
Where is the turf reinforcement mat for the detention basin sides? Correction required.
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Miscellaneous Correction
Corrective Action Required
It is likely you are wanting to grade the detention basin one time, and install the outlet structure one time rather than retrofit later. As such, all aspects of the unapproved final stormwater report shall be addressed, and all aspects of the detention basin outlet structure shall be addressed on the plans, and all aspects of the sediment basin design shall be addressed, such as sizing of skimmer, placement of skimmer, etc. Correction required.
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Miscellaneous Correction
Corrective Action Required
Stormwater Study Comments: 1) Isn't the methodology of the report to determine whether the detention system is capable of meeting Section 5600 Comprehensive Control Strategy?, 2) you are proposing 0% slope for the bottom? How is this going to work? We have seen less than 2% in the past, but 0% is going to unnacceptable and will lead to mosquito breeding and stagnant water, 3) Conclusions and Recommendations did not mention anything about meeting Section 5600 Comprehensive Control Strategy, 4) no discussion of potential stream buffer issues was presented, and calculation of the drainage area upstream of the outlet structure was not addressed, 5) no discussion of eliminating impact to resididential properties to the west was presented in the report, and how a drainage swale would be constructed to address this issue, 6) no discussion of width of top of dam and what would be sufficient based on your recommendations, 7) no discussion of how the water quality orifice is going to remain clog-free, 8) no discussion of the emergency spillway in terms of providing a safe path for discharge of the design event, 9) any wetland issues, 10) any U.S. Army Corps of Engineers issues.
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Miscellaneous Correction
Corrective Action Required
The zero percent slope within the bottom of the basin is a questionable design and is going to lead to public safety issues such as mosquito breeding. This will take place adjacent to a residential subdivision. As previously commented, this 0% slope will not be approved. Corrections required.
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Miscellaneous Correction
Corrective Action Required
There are still questions regarding the scale of the plans. Without an accurate scale, I am reluctant to provide any review of the required storage volume shown in the report. Review to be delayed until the scale issue is resolved.
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Miscellaneous Correction
Corrective Action Required
Cost estimate required prior to formal approval. Correction required.
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