#16 - Highpointe Crossing Preliminary Plat and OP PUD

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PAGE 4 of 6  The executive summary must include a summary of existing and proposed curve numbers, summary of stormwater basins with their resulting normal water level (NWL) and high‐water level (HWL) for each NURP pond, and a summary of the volume extraction requirements and extraction volume provided by each pond. The pre and post development NWL and HWL must also be provided for all wetlands. 3. The SWMP is required to verify that rate control requirements are met for all points of discharge from the site. Curve numbers must be adjusted per the attached Memo prepared by Bolton and Menk dated June 25, 2024. 4. Revisions to the volume control requirements and water quality treatment must be completed and resubmitted for further review; per the attached Memo prepared by Bolton and Menk dated June 25, 2024. 5. Stormwater Reuse System. The SWMP must indicate that the stormwater reuse system must be provided in accordance with the City design standards for Stormwater Reuse. 6. For stormwater reuse systems, City design standards require that flood management provisions be implemented for all new developments assuming no storm water reuse irrigation is operating. The SWMP executive summary must be revised to clarify that all 100‐year HWL flood elevations were determined assuming no volume reduction is occurring for storm water reuse irrigation at the time of the flood event. 7. The SWMP executive summary must include reuse system design and operating criteria, including identification for the collection area for the reuse pond, a summary of the dedicated irrigation areas, by lot and Outlot, the assumed application rate and frequency, the storage requirement for the reuse pond, and the storage area available. 8. Stormwater Irrigation Plan Sheet. The Preliminary Irrigation Map must be revised to include the following information for City review, and must be revised as needed to meet the following design criteria:  Area to be irrigated with a chart summarizing the area calculations together with an exhibit. For these calculations the contributing area for each private lot must be limited to the maximum allowable impervious surface. Areas with slopes of 3H:1V or greater should be removed, as well as removing all drainage ditches and swale areas.  Identification of the source pond, pond name and depiction of the drainage area to source water.  Location of reuse system components, including the pump, intake from pond, usage meter, location of potable connection (if applicable), location of backflow prevention device (if applicable), location and type of filters (if applicable), location of debris collection sumps (if applicable).  Location of maintenance access.  Drawdown elevation of pond.  Irrigation pipe routing that is proposed. Irrigation system supply and feeder lines must be shown to not encroach City drainage and utility easements with the exceptions of perpendicular crossings. If irrigation piping is proposed within any City right‐of‐way, the detailed piping locations must be provided for City review and approval. 9. The Reuse Pond should be revised as necessary to meet the following design criteria:  The Reuse Pond should be sized to provide a minimum of 4 times the weekly irrigation demand within the reuse zone. The reuse zone is the allowable drawdown zone of the pond for water reuse and is defined as the volume between the “off” elevation and the normal water level.  The Reuse Pond should be designed so a minimum depth of four feet remains below the reuse zone of the pond.  The Pond reuse zone shall have a slope shallower than 5H:1V and be stabilized with tolerant vegetation or bank armoring. The grading plans must be revised accordingly. 10. Revise the grading plans to provide the NWL and HWL for all water bodies including NURP ponds and wetlands. HWL contours must be shown on the plans to verify that flood levels are contained. 11. All wetlands and wetland buffers must be protected by easement and may not encroach individual lots. 12. Minimum floor elevations must be at least 2 feet higher than the adjacent 100‐year HWL elevation. Also, all low opening elevations for all buildings must be at least 1‐ft higher than any adjacent emergency overflow elevation (EOF). 13. All localized low points must be protected within a drainage easement. All localized low points must include the 100‐year HWL and HWL contour on the grading plans.