CDI - Application Status

APN: 031-071-56 Reviewer: Jennifer Buckley 1st Routing Comments

The application to construct a new residence and ADU on Lot 3 of MLD 15-1244 has been received by the Stormwater Section of the County of Santa Cruz. The submittal has not been approved, please review and address each of the comments below (all applicants are required to follow the design requirements as outlined in the County of Santa Cruz Design Criteria referred to as the CDC hereon). The CDC can be found on the internet by navigating to County of Santa Cruz Public Works Department, Stormwater, Design Criteria (http://www.dpw.co.santa-cruz.ca.us/).

1. Please complete Appendix A of the CDC, Project Information and Threshold Determination Form, which can be found on the internet by navigating to County of Santa Cruz Public Works Department, Flood Control & Stormwater, Permit Requirements, Project Information and Threshold Determination Form. Please include all new and/or replaced impervious and semi-impervious surfaces as part of this project in Appendix A.

2. Per Sheet C4.0 of the approved improvement plans, the raingarden mitigation was designed assuming 2,500 square feet of impervious area draining to it. The building permit plans show that more than 2,500 square feet of impervious area is planned for the site. Please either reduce the impervious area on the site to 2,500 square feet or less or provide updated calculations and construction cross-section details demonstrating that the raingarden is sized to retain a 25-year storm event.

3. Please show how stormwater runoff from the impervious surfaces will be controlled and conveyed to the raingarden.

4. Please ensure that the flowlines of the grass drainage swales shown on Sheet C1 of the building permit plan set are sloped a minimum of 2% to be consistent with the approved MLD plans. Alternatively, updated calculations may be provided for the proposed swales that demonstrates safe conveyance of runoff from a minimum 25-year storm in accordance with Part 3, Section H of the CDC.

5. Please show a grass swale at the northwest corner of the property with a minimum 6-inch gap at the bottom of the fence line for 5 feet in the vicinity of the swale to be consistent with the approved MLD plans.

6. Please add a note to Sheet C1 of the building permit plan that references Sheet C3.0 of the approved MLD plans for the permeable paver detail.

7. Zone 5 fees will be assessed on the net increase in permitted impervious area following the Unified Fee Schedule in place at building permit issuance. Reduced fees (50%) are assessed for semi-pervious surfacing without liners (such as gravel, base rock, paver blocks, porous pavement, etc.) to offset costs and encourage more extensive use of these materials.

Comments 8 through 11 below are notifications to the applicant of holds that will be placed on the permit once it is ready to be issued by the Planning Department. These items are not required to be addressed/completed prior to resubmittal but shall be addressed prior to occupancy.

9. Please coordinate with the developer to obtain a revised, notarized, and recorded maintenance agreement (SWM-25B form) with an operations and maintenance manual. The O&M has already been prepared by Ifland Engineers. The revised maintenance agreement shall designate a single point of contact to provide an annual stormwater maintenance report and annual fee for all four lots of MLD 15-1244. Alternatively, the revised maintenance agreement could acknowledge that future payment, maintenance, and reporting will be provided by the property owner of each lot, and that each owner will be billed the full amount. It will be the responsibility of the property owner and/or designated single point of contact to submit annual maintenance reports and associated annual fees to the Department of Public Works following the Unified Fee Schedule in place at the time billed. The annual fee as of October 2021 is $650.00 and is subject to increase annually.

10. A hold will be placed for final as-built plans prepared by the project civil engineer.

11. A hold will be placed for final drainage construction sign off by the DPW County Inspector.

APN: 031-071-56 Reviewer: Jennifer Buckley 2nd Routing Comments

The application to construct a new residence and ADU on Lot 3 of MLD 15-1244 has been received by the Stormwater Section of the County of Santa Cruz. The submittal has not been approved. Some of the first routing comments were not completely addressed. Please review and address each of the comments below.

1. Thank you for submitting Appendix A which shows that 2,897 square feet of impervious area will be constructed on the site. Per Sheet C4.0 of the approved improvement plans, the raingarden mitigation was designed assuming 2,500 square feet of impervious area draining to it. The building permit plans show and additional 397 square feet of impervious area draining to the raingarden. Please either reduce the impervious area on the site to 2,500 square feet or less or provide a full set of updated calculations demonstrating that the raingarden is sized to retain a 25-year storm event. The Raingarden Design Information Table on the Grading, Drainage & Utilities Plan by Sterling Consultants is not adequate. Calculations are needed to show the method in which the size and volume of the mitigation was derived.

2. Please show how stormwater runoff from the impervious surfaces will be controlled and conveyed to the raingarden. Please show the locations of the roof downspouts and whether runoff will be piped to the raingarden or conveyed via swales. If swales will be used to convey the roof runoff, then please provide additional flowline elevations to clearly show the slope of the swale flowline toward the mitigation. If pipes will be used, please modify or remove the note on Sheet A1.1 that states all RWL to have splash blocks.

3. The proposed storm drain system shall be sized to adequately meet the minimum hydrology design requirements in Sections H though J of the CDC. Please provide calculations to show that swales have been designed to safely convey runoff from a minimum 25-year storm event.

APN: 031-071-56 Reviewer: Jennifer Buckley 3rd Routing Comments - Approved