NOTICE: The fourth edition of the Hydrology Manual was approved and adopted by the Chief Engineer and General Manager of the Flood Control District of Maricopa County on September 9, 2013. This edition does not include any significant changes made since the November 18, 2009 edition. Refer to the Revisions section of the Hydrology Manual for more detail.
The objective of the Drainage Design Manual, Hydrology, is to provide criteria and design guidance for estimation of peak discharges and runoff volumes for use in identifying flood hazards and design of drainage facilities in Maricopa County. This manual provides a convenient source of technical information that is specifically tailored to the unique hydrologic, environmental and social character of Maricopa County; and a consistent set of criteria that, when used by the local governing agencies and the land development community, will result in uniform drainage practices throughout the County.
This document is only advisory and, in conformance with A.R.S. 48-3641.6, is intended to inform the general public of the Flood Control District of Maricopa County's current approach or opinion to the requirements of the various federal, state and county floodplain and drainage related ordinances or regulations, including, where appropriate, the Flood Control District of Maricopa County's current recommended minimum practice, procedure or method of action based on that approach or opinion. This document is not intended to impose additional requirements or penalties on regulated parties or confidential information. Submissions made using other methodology shall be acceptable to the Flood Control District of Maricopa upon submission of scientific documentation and evidence showing that such methodology yields results that are consistent and in accordance with the requirements of the various ordinances and regulations. However, the burden of proof is on the applicant and may affect submittal review times.
The fourth edition of the Hydrology Manual does not include agency-specific policies and standards. It only contains technical guidance.
Comments on the Hydrology Manual are encouraged and should be directed to:
Special Projects Branch Manager
Flood Control District of Maricopa County
2801 W. Durango Street
Phoenix, AZ 85009
It is preferred that comments be submitted to Mr. Loomis by e-mail.
The EFFECTIVE Hydrology Manual is now the 4th Edition dated August 15, 2013, with Chief Engineer and General Manager approval dated September 9, 2013.
The fourth edition of the Manual is only available in a digital PDF (Portable Document File) format, which requires the free Adobe Reader to view. To save the document directly to your hard drive, right click on the link and select "Save Target as." If you do not already have the Adobe Reader, click on the following Adobe link: