CDI - Application Status

The application for the new retaining wall & storm drain improvements has been received by the Stormwater Section of the County of Santa Cruz. The current submittal has not been approved, please review and address each of the comments below:

1. The County of Santa Cruz Design Criteria (CDC) requires all drainage improvements to be designed so that they can convey a 10 year storm, at a minimum. Please show that the system is adequately sized to convey the anticipated storm event, and also include a tributary drainage area map that clarifies the amount of runoff to be intercepted and conveyed by the proposed improvements.

a. Please refer to Section D, Hydrology – Minimum Design Requirements, from the CDC (pg. 63) for further guidance. This improvement must also be capable of conveying a 25 year flood overflow event. Please provide supplemental information to show that the proposed grate and 8” conduit will adequately accept and convey the required 25 year flood overflow volume as well.

b. A copy of the County Design Criteria (CDC) can be found online by using the following link: http://www.dpw.co.santa-cruz.ca.us/Portals/19/pdfs/DESIGNCRITERIA.pdf?ver=2017-04-27-134016-453

2. Please revise the supplied tabulation table to more clearly show all existing impervious area that will be removed along with all new impervious areas that are to be constructed as part of this building permit application.

3. This project is within an established Flood Control District as part of the Santa Cruz County and shall be charged a fee based on the total new permitted impervious area created. The current fee is $1.27 per square foot but is subject to change based on the most updated fee amount applicable at the time of permit issuance. The County of Santa Cruz currently has four Zones with the associated fee rate (Zone 5 established in 1969, Zone 6 established in 1986, Zone 7a established in 2005, & Zone 8 established in 1977).

a. This project may be eligible for fee credits for existing impervious areas previously permitted or built prior to the established flood control zone if acceptable documentation is presented. (Acceptable documentation can be in the form of an assessor’s record, survey record, permit record, dated aerial photograph(s), or another official record that can confirm a previously permitted structure.) Otherwise County staff will utilize the most relevant aerial photos to establish credit if no additional information is furnished by the applicant.

b. A 50% credit is given to all projects that implement semi-pervious surfaces such as: pervious/porous/permeable pavers, porous concrete, porous asphalt, baserock, etc.

4. It appears as though a portion of this parcel is located within the 100-year floodplain. Please identify the local floodplain elevation on the supplied plan set.

5. Please provide a maintenance schedule establishing the ongoing requirements for maintenance and monitoring of all permanent stormwater management facilities in compliance with County Code 7.79 (this schedule shall also be included in the maintenance agreement as a packet when the applicant records and notarizes their SWM-25A form). The Mt. Hermon Association will be required to submit a maintenance agreement to the County of Santa Cruz, establishing that they are solely responsible for any/and all maintenance inspections and expenses.

a. A recorded maintenance agreement will be required for the drainage system on this parcel. Please include the following additional information as required by the CDC:

i. Statement of the operating requirements to ensure proper performance of the stormwater management facility.

ii. Specification of any Best Management Practices that must be implemented and maintained.

iii. Specification of any restriction on system use or property use, such as limitations on amount of impervious surface, limits on fertilizer or pesticide use, limits on vehicle parking or maintenance, restrictions on building additions, etc.

iv. Notification that the property owner may be required to report to the County on the management and maintenance of the stormwater management facility.

v. The maintenance agreement shall be binding on and shall inure to the benefit of the successors, heirs, executors, administrators, and assigns of the owner.

b. Please contact the County of Santa Cruz Recorder’s office for appropriate recording procedures. The maintenance agreement form can be picked up from the Public Works office or can be found online at: http://dpw.santacruzcounty.us/Portals/19/pdfs/FigureSWM25A.pdf

6. Upon approval of the project, a drainage “Hold” will be placed on the permit and will be cleared once the construction is complete and the stormwater management improvements are constructed per the approved plans: In order to clear the Hold, one of these options has to be exercised:

a. The civil engineer must inspect the drainage improvements on the parcel and provide public works with a letter confirming that the work was completed per the plans. The civil engineer’s letter shall be specific as to what got inspected whether invert elevations, pipe sizing, the size of the mitigation features and all the relevant design features. Notes of “general conformance to plans” are not sufficient.

b. As-built plans stamped by the civil engineer may be submitted in lieu of the letter. The as-built stamp shall be placed on each sheet of the plans where stormwater management improvements were shown.

c. The civil engineer may review as-built plans completed by the contractor and provide the county with an approval letter of those plans, in lieu of the above two options. The contractor installing the drainage improvements will provide the civil engineer as-built drawings of the drainage system, including construction materials, invert elevations, pipe sizing and any modifications to the horizontal or vertical alignment of the system. The as-built drawings, for each sheet showing drainage improvements and/or their construction details, must be identified with the stamp (or label affixed to the plan) stating the contractor’s name, address, license and phone number. The civil engineer will review the as-built plans for conformance with the design drawings. Upon satisfaction of the civil engineer that the as-built plans meet the design intent and are adequate in detail, the civil engineer shall submit the as-built plans and a review letter, stamped by the civil engineer to the County Public Works Department for review to process the clearance of the drainage Hold, if the submittal is satisfactory.

Contact Forrest Revere, if you have questions about the above comments. Email: dpw172@santacruzcounty.us Counter: Monday-Friday 8:00-12:00 PM Phone: 831-454-2160