https://www.americancityandcounty.com/wp-content/themes/acc_child/assets/images/logo/footer-logo.png
  • Home
  • Co-op Solutions
  • Hybrid Work
  • Commentaries
  • News
  • In-Depth
  • Multimedia
    • Back
    • Podcast
    • Latest videos
    • Product Guides
  • Resources & Events
    • Back
    • Resources
    • Webinars
    • White Papers
    • IWCE 2022
    • How to Contribute
    • Municipal Cost Index – Archive
    • Equipment Watch Page
    • American City & County Awards
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Cookie Policy
    • Privacy Statement
    • Terms of Service
American City and County
  • NEWSLETTER
  • Home
  • Co-op Solutions
  • Hybrid Work
  • Commentaries
  • News
  • In-Depth
  • Multimedia
    • Back
    • Podcasts
    • Latest videos
    • Product Guides
  • Resources/Events
    • Back
    • Webinars
    • White Papers/eBooks
    • IWCE Expo
    • Calendar of Events
    • How to Contribute
    • American City & County Awards
    • Municipal Cost Index
    • Equipment Watch Page
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Cookie Policy
    • Privacy Stament
    • Terms of Service
  • newsletter
  • Administration
  • Economy & Finance
  • Procurement
  • Public Safety
  • Public Works & Utilities
  • Smart Cities & Technology
  • Magazine
acc.com

Smart Cities & Technology


County manages floodplains with updated photos

County manages floodplains with updated photos

Until recently, Maricopa County, Ariz., used semirectified aerial photography in a GIS to help manage floodplains. However, the photographs lacked positional
  • Written by Tom LaMarche
  • 1st October 2001

Until recently, Maricopa County, Ariz., used semirectified aerial photography in a GIS to help manage floodplains. However, the photographs lacked positional accuracy, and the county’s flood insurance maps overlaid poorly on them. Floodplain managers were reluctant to use the photographs internally and in public forums because of discrepancies. The county decided it needed to upgrade its GIS to include orthophotographs — map-accurate aerial photographs — of 7,931 square miles.

In late October 2000, its decision was validated when unexpected heavy rain fell in Wenden, a town of 700 residents in the northwest part of the county. The town is in a region that barely averages six inches of rain a year, but remnants of Hurricane Nora sent a wall of water through the many farming communities in the area. The county needed to compile flood data quickly to qualify for a grant from the Federal Emergency Management Agency.

“We usually conduct the annual aerial imaging project in December and January and share the information with the county tax assessor,” says GIS Manager Marta Dent. “Suddenly we needed the data turned around in less than half the time we normally require.”

That November, the county contracted with Irvine, Calif.-based Landata Airborne Systems to create black and white digital orthophotography at one-foot pixel resolution. For the purpose of flood analysis, the firm also provided 3-D digital images of the entire hydrographic network in the county.

The firm used a high-accuracy control network of points known as the GDACS (geodetic densification cadastral survey) points to spatially locate the photographs, providing a common background for data shared by flood analysis, tax assessment, transportation, planning and disaster preparedness agencies. County surveying crews verified that the photographs matched the GDACS points well within plus or minus five feet.

The county has used the one-foot pixel resolution photographs to determine flood hazards for properties, to determine where the road network needs improvements and to assess property taxes. It also is using the photographs to verify the accuracy of its parcel maps, which are being converted into digital format.

Using orthophotography has transformed the county’s approach to floodplain management. Now, the county can conduct studies using the newly generated terrain models and the photography, without the need for conducting additional expensive fieldwork. In addition, the improved image quality and accuracy has allowed the Flood Control District to significantly enhance its public information effort in floodplain management.

For example, the district recently created a floodplain management plan in a developing area where there previously had been none. With the new orthophotography, the GIS staff quickly assembled photo-based maps showing the floodplain plan and published them on the district’s Web page.

This article was written by Tom LaMarche, IT division manager for the Maricopa County Flood Control District.

Tags: Smart Cities & Technology

Most Recent


  • artificial intelligence
    Artificial intelligence for cities and counties
    It appears that artificial intelligence (AI) is everything, everywhere and in every product the vendor community would have us buy. However, despite the hype, few dismiss it as just another high-tech fad. Indeed, some believe it is the third (or fourth) wave, depending on how one is counting in the ever-evolving digital age. As early […]
  • dashboards
    Dashboards and software help simplify financial funding and reporting for cities and counties
    Governments are streamlining management of federal funds through technology, says Mike Bell, CEO of Envisio, which provides public dashboards, analytics and performance management software. About 150 local government, education and nonprofit organizations use his firm’s solutions to manage their strategic plans, improve performance and report on results. Envisio is helping local government agencies to satisfy […]
  • traffic
    Reimagining how cities can leverage holistic platforms for urban mobility solutions
    When it comes to designing transit and transportation solutions that reduce traffic congestion and improve on-time arrival rates, we seem to have a problem. It seems we are focused on all the wrong things. It’s not all about building a better vehicle, or the technology that is used inside the vehicle. And it’s not about […]
  • data
    Data: Your most overlooked asset
    If asked to think of a community’s most important assets, many would likely start by naming road networks, bridges, buildings, or possibly even transit and sanitary systems. But would data ever come to mind? As the foundation of everything, data is a vital asset—especially for public sector organizations. In order to have confidence in the […]

Leave a comment Cancel reply

-or-

Log in with your American City and County account

Alternatively, post a comment by completing the form below:

Your email address will not be published. Required fields are marked *

Related Content

  • MS-ISAC members get free access to Deloitte’s Cyber Detect and Respond Portal to help respond to cyber threats
  • North Texas alliance partners with Marketplace.city on smart government solutions
  • Harris County deploys next-generation security in 150 public buildings
  • Prioritizing rapid restore leads to stronger ransomware attack recovery

White papers


7 Resources to Level-up Your Federal Grants Administration and Compliance

5th September 2023

Elevator Phone Line Replacement Strategy | A Guide to Reliable, Code-Compliant Solutions

29th August 2023

2023 State of Public Sourcing Report: The Bright Future of Public Procurement

23rd August 2023
view all

Webinars


Grant Preparedness: Unlocking Funding Opportunities for Your Success

10th August 2023

2023 State of Public Sourcing: Taking Local Governments into a Bright Future

1st August 2023

Stop Playing with Fire: How to Manage Infrastructure Asset Risk So You Know You’re Covered

20th June 2023
view all

PODCAST


Young Leaders Episode 4 – Cyril Jefferson – City Councilman, High Point, North Carolina

13th October 2020

Young Leaders Episode 3 – Shannon Hardin – City Council President, Columbus, Ohio

27th July 2020

Young Leaders Episode 2 – Christian Williams – Development Services Planner, Goodyear, Ariz.

1st July 2020
view all

GALLERIES


Gallery: Hottest temperatures recorded in American cities during July

12th September 2023

The top 10 Asthma Capitals for 2023

7th September 2023

U.S. cities with the cleanest air from latest “State of the Air” report

5th September 2023
view all

Twitter


Newsletters

Sign up for American City & County’s newsletters to receive regular news and information updates about local governments.

Resale Insights Dashboard

The Resale Insights Dashboard provides model-level data for the entire used equipment market to help you save time and money.

Municipal Cost Index

Updated monthly since 1978, our exclusive Municipal Cost Index shows the effects of inflation on the cost of providing municipal services

Media Kit and Advertising

Want to reach our digital audience? Learn more here.

DISCOVER MORE FROM INFORMA TECH

  • IWCE’s Urgent Communications
  • IWCE Expo

WORKING WITH US

  • About Us
  • Contact Us

FOLLOW American City and County ON SOCIAL

  • Privacy
  • CCPA: “Do Not Sell My Data”
  • Cookie Policy
  • Terms
Copyright © 2023 Informa PLC. Informa PLC is registered in England and Wales with company number 8860726 whose registered and Head office is 5 Howick Place, London, SW1P 1WG.