Drainage Design Manual, Hydrology - Flood Control District of ...

Drainage Design Manual for Maricopa County
Hydrology: Introduction
1.4 USING THIS MANUAL
The use of the methods presented in this manual, even the rigorous application thereof, in no
way ensures that the predicted values are reasonable or correct. Hydrology is a discipline which,
in some respects, is much like music – quality requires not only technical competence but also a
feel for what is right. It often requires the exercise of hydrologic judgement. The user of this
manual is directed to validate the reasonableness of the predicted values by applying alternative
methods, such as envelope curves, regression equations, or other checks which have been
developed for this area and are provided in this manual. Failure to verify predictions may result
in erroneous values.
It is not the intent nor purpose of this manual to inhibit sound innovative design or the use of new
techniques. Therefore, where special conditions or needs exist, other methods and procedures
may be used with prior approval.
1.5 APPLICATION
The contents of this manual, with the exception of Chapter 3 (Rational Method) and Chapter 8
(Indirect Methods), were prepared to supplement the most current version of HEC-1 User’s Manual
(U.S. Army Corps of Engineers). Although the use of the HEC-1 Flood Hydrology Program is
not required in conjunction with the procedures in this manual, its use will greatly facilitate the
execution of the recommended procedures that are contained herein. The Flood Control District
has written a HEC-1 interface program, Drainage Design Management System for Windows
(DDMSW)‘, which enhances and simplifies the use of the HEC-1 program with the procedures of
this manual. DDMSW is available on the district’s website at www.fcd.maricopa.gov.
1-6 August 15, 2013