Doing Business With the District

The Flood Control District is pleased to work with businesses and stakeholders to increase public safety for citizens throughout Maricopa County. One of our goals is to continuously provide timely resources that communities can utilize to identify flood hazards and construct flood control infrastructure.

The District encourages you to visit the Maricopa County Enhanced Regulatory Outreach Program (EROP) website to review flood control, and other, county regulations prior to planning projects.

Consultants & Contractors 

Invitations for bid and/or requests for qualifications for Maricopa County can be found at You must be registered to view solicitations.

Additional instructions for registering on BidSync and how to respond to a bid can be found on our Vendor Registration page.

Upcoming Projects

View a list of upcoming construction and consulting projects for Flood Control District that are not yet out for bid.

Related Documents

Available Software

The District provides useful engineering software and training opportunities for the benefit of the private and public sector working on hydrology, hydraulics, and flood control projects. 

The software can be used for hydrologic, hydraulic, river mechanic modeling as part of Maricopa County's permit application (drainage use permit, floodplain use permit, sand and gravel permit, and right-of-way permit) as well as the District's floodplain delineation studies, watercourse master studies/plans, area drainage master studies/plans, and capital improvement projects.

Software and resources listed on this site are provided as a public service. The use of the software, results, and any information of this web page is the responsibility of the user. The user releases, indemnifies and holds free the Flood Control District of Maricopa County from any and all liabilities, damages, lawsuits, and causes of action that result as a consequence of their reliance on this webpage.

Drainage Design Management

Drainage Design Management System



HEC-1 HC Card Drainage Area Calculation Tool

HEC-1 HC Card Tool

NSTPS Tool 1.0.0


Technical Tools

Flood Control District Library

Search through a variety of additional resources, completed studies and manuals made available online on our Flood Control District Library.

HEC-1 HC Card Cumulative Drainage Area Calculation Tool

View more information and download the tool.

The software is designed to automatically calculate the drainage area at each hydrologic concentration point in an existing HEC-1 input file.

FLO-2D Web Access Tool

Open the map

This map is intended for use by experienced engineers as a design aid for preparing site drainage and grading plans, and for establishing building lowest floor elevations for new structures. Users are strongly encouraged to consult with District staff or the appropriate governing agency prior to applying this information for the first time to obtain a clear understanding of the basis for the information and for guidance in its application. The map, however, is not an official document that may be used for floodplain determination.

These maps are designed to assist in obtaining the results of two-dimensional hydrologic and hydraulic modeling prepared as a part of Area Drainage Master Studies/Plans or Floodplain Delineation Studies . The information available are estimates of the peak discharge in cubic feet per second from designated storm frequencies, the dominate direction of that discharge, and the resulting peak water surface elevation on the NAVD 1988 vertical datum. The results are the average for each grid element.

NSTPS Tool 1.0.0

Released: June 17, 2013 (Beta version)

NSTPS Tool 1.0.0 is a software package designed to automatically update the NSTPS parameter (HEC-1 RS card's first field) for flow routing in channels in an HEC-1 input file.

Customized HEC-HMS Features for Maricopa County

HEC of USACE recently added Maricopa County's Green-Ampt rainfall infiltration method, Clark unit hydrograph, and S-graph unit hydrograph to HEC-HMS 4.9 or newer based on the 2018 Drainage Design Manual (Hydrology).

Drainage Design Management System

The latest version (Version 6.0.5 - February 2022), as well as prior versions and upgrade versions of the DDMSW, are available via this website for free download.

The DDMS is a Windows tool that was initially developed as a pre-processing tool for HEC-1 modeling. Additional functionalities have been added; which include Storm Drainage Hydraulics and River Mechanics.

Commonly Downloaded Manuals

Best Management Practices

Best management practices (BMPs) help control urban storm runoff by reducing runoff and improving water quality from storm events. BMPs include structural controls such as infiltration devices, ponds, filters and constructed wetlands, and non-structural controls such as maintenance practices, street sweeping, public education and outreach programs.

View individual drawings of our Best Management Practices (BMP) as PDF files or alternatively, you can download the entire set of BMP Drawings as DGN files.