I. ALLOWABLE CREDITS
A. Maximum Total Credit: The maximum total credit attainable will be 85%.
B. Maximum Credit for Reducing Flow Rate: 60%.
C. Maximum Credit for Reducing the Volume of Discharge: 25%
II. CREDITS FOR REDUCING FLOW RATE
A. First Tier Credit
For meeting the minimum standard of limiting the peak discharge from a 4.25-inch, 24-hour storm to that existing prior to development, the user shall be granted a credit of 10%.
B. Second Tier Credit
For reducing the peak discharge from a 4.25-inch, 24-hour storm to 0.40 cfs per acre, the user shall be granted an additional credit of 20%.
C. Third Tier Credit
For reducing the peak discharge from a 4.25-inch, 24-hour storm to 0.30 cfs per acre, the user shall be granted an additional credit of 15%.
D. Fourth Tier Credit
For reducing the peak discharge from a 4.25-inch, 24-hour storm to 0.15 cfs per acre, the user shall be granted an additional credit of 15%.
III. CREDITS FOR REDUCING VOLUME OF FLOW
A. For limiting the maximum 12-hour volume of runoff from a 25-year storm to that existing prior to development, the user shall be granted a full credit of 25%. To receive this credit, at the end of the 24-hour period during which the runoff event occurred, the facilities used for the mitigation of the effects of runoff must be returned to the state existing at the beginning of the runoff event, or the terminal state must be considered in determining credits for reducing flow rate. Alternatively, it may be demonstrated that the conditions at the end of the 24-hour period would not impact the ability of the facilities to mitigate the affects of a second similar runoff event.
B. For reducing the maximum 12-hour volume of runoff for the 25-year storm by an amount less than that set forth in Paragraph III.3.a, the user shall be granted a credit in accordance with the following formula:
Credit = Runoff without Mitigation - Runoff with Mitigation *25%
Runoff without Mitigation - Runoff Prior to Development
C. No credit will be allowed for reducing the volume of flow, unless it exceeds 5%.
IV. REQUIRED DOCUMENTATION
Any request for credit(s) shall contain the following information:
1) Tax Parcel Number
2) Parcel Address
3) Owner Name
4) Owner Address
5) Amount and Type of Credit(s) Requested
6) The Name, Address, and Telephone Number of the Contact Person
B. Certification of Proper Installation, Operation and Maintenance
The applicant shall provide written certification that the facilities that are the subject of the credit request are:
1) Constructed in accordance with plans submitted to obtain approvals for land subdivision or other government or agency permits.
2) Operated in a manner to assure that they function as intended.
3) Maintained in a manner to assure that they remain as constructed and function as intended.
C. Other Documentation
The party requesting credit(s) for the mitigation of runoff effects shall provide a hydrologic and/or hydraulic studies, plans, etc. that demonstrates, to the satisfaction of the Storm Water Utility, that the measures taken or proposed meet the requirements for the credit(s) requested.