Why are so many flood maps still out of date

A Q&A with Professor David Maidment on what makes today's maps 10 times more accurate than the ones much of the US is still stuck with

The Federal Emergency Management Agency’s (FEMA) flood insurance maps are critically important for millions of Americans who live in flood-prone areas. The maps determine the annual premiums for flood insurance, which is required by law for homeowners with federally backed mortgages who live in high-risk areas. But many of the nation’s flood maps are woefully out of date.

ProPublica talked with David R Maidment, a professor at the University of Texas at Austin who has advised FEMA on flood mapping, about why the data behind modern maps is 10 times as accurate as the older data and why half of Texas still doesn’t have up-to-date maps.

How did you become involved with flood mapping?

I was the drainage engineer for a small community out in Rollingwood, Texas. It’s a small suburb of Austin, and it was hit by a big flood in 1981, which is when I joined the University of Texas at Austin. They didn’t have much of any regulation at the time, and so people did more or less whatever they wanted, and they put buildings wherever they wanted. It was clear that we needed a better system.

Why is it important to have up-to-date flood maps?

Flooding is the natural disaster that impacts people more than any other.

Since federal disasters started being declared in 1952, two-thirds of them have involved flooding. The next one after that is fire. There have been about 300 federal disasters declared from fire and 1,600 from flooding. Fire is a very horrible thing, but flooding occurs much more frequently, and it’s also much more widespread. That’s the fundamental reason. Floods devastate human lives to a greater extent than any other national hazard.

What’s changed since you started studying flooding?

The big change, which happened about 10 years ago, was the conversion of maps from a paper system into a digital system. That was a very large investment of federal funds. It’s considered to be the largest civilian mapping program in the world.

How up to date are FEMA’s flood maps now?

It varies quite a bit. The data in cities is generally pretty good. It’s once you get outside of the cities that things start falling away. The original question that we were asked to investigate was whether it was possible to produce updated flood maps with out-of-date terrain and panametrics information. Flood maps have two-dimensional information that says, ‘Where are things on the ground?’ And they have three-dimensional information, which says, ‘How high is the land?’ We found that the two-dimensional data — where are things horizontally? — is actually pretty accurate, because it’s being done with image mapping now, and the emergence of Google Earth and other things like it have made image mapping really accurate. What we found was out of date was the nation’s three-dimensional elevation data, which in many cases was drawn from U.S. Geological Survey topographic maps that were developed 30 or 40 years ago, using mapping processes that aren’t as accurate as what is now possible.

What makes the new maps more accurate than the old ones?

The big improvement that’s happened is in the vertical elevation data. There’s a new technology that’s emerged called lidar, and what it involves is having an airplane flying over the land and firing out a bunch of laser pulses in kind of a beam. The beam comes out of the airplane and hits a mirror that goes left and right as the airplane goes forward. So there are billions of pulses that hit the ground and bounce back to the airplane again. About a third of the country has been covered with lidar now. The three-dimensional elevation data that it generates is about 10 times more accurate than the old data.

If you live somewhere prone to flooding, what do these improvements mean?

There’s a much more precise definition of what the real flood risk is. Also, they make it possible to define how deep the water will be. In the old flood plain maps, the only question they answered was, ‘Is your building anywhere within the floodplain boundary?’ And with the more accurate three-dimensional data, different questions can be asked: What is the likelihood that your building will flood? And if it does flood, how deep will the water be? It wasn’t possible to answer any of those questions before.

And FEMA couldn’t do that with the old maps?

No. The old maps were 2D — they were paper maps. There was no 3D aspect to them at all.

How much of the country has these newer, more accurate flood maps?

The original intention was to cover the whole United States, coast to coast, with digital flood maps. But it turned out they had a billion dollars — $200 million a year, over five years — to do that, and it wasn’t a billion-dollar job. It was probably a $10 billion job, or a $20 billion job. It turned out to be much more expensive to do that than what had been anticipated at the beginning. And so FEMA cut back on the original goals, and instead focused on the areas of highest flood risk, which generally are associated with high-population zones and zones near the coast. They quantified the flood risk in about 65 percent of the country that contained 92 percent of the population. That means that in the populated areas, the flood maps are actually in pretty good shape now. But in the unpopulated areas, in many cases there are no updated maps at all. Half of Texas, for example, has no flood maps. And I’m distressed about that, because we’re still not where we need to be.

This interview has been edited for clarity and length.




Ramesh Poapt

4 years ago

What about India ?
Is National Disaster Management fully active,updated n alert?

RTI Judgement Series: How retired employees made to run from pillar to post for dues

The CIC directed the deputy director of education department to provide information to the appellant about the delay and action taken against persons responsible for it. This is the 130th in a series of important judgements given by former Central Information Commissioner Shailesh Gandhi that can be used or quoted in an RTI application

The Central Information Commission (CIC), while allowing an appeal, said, that the appellant was rightly agitated since she had been made to run from pillar to post to get her legitimate retirement dues. The Commission also directed the deputy director of education department to provide information about the delays, persons responsible for it and action taken against those responsible for the delay in providing retirement dues.


While giving this judgement on 7 July 2009, Shailesh Gandhi, the then Central Information Commissioner said, “A society and the Government that proclaims special treatment to senior citizens must find ways of ensuring a dignified retirement for those who have served society.”


Delhi resident husband and wife Nishchint, on 17 February 2009, sought information on her retirement dues from the Public Information Officer (PIO) of Balvantray Mehta Vidya Bhawan, Senior Secondary School of Servants of the People Society. Here is the information they sought under the Right to Information (RTI) Act and the reply given by the PIO...


1. What is the status of Appellant's file of retirement?  The daily progress report of his file.  

PIO's reply-

  • Retirement papers were submitted to Account Officer, Distt. South on 12 November 2008 after fixation of Pay as per VI Pay Commission Report.
  • File as re-submitted on 5 December 2008 after rectification of pension as per new rule. 
  • Department of Education verified all the documents and asked to deposit Pension Contribution Rs2,847 to PAO-II, RK Puram, which was deposited on 25 February 2009.


2. What is the procedure for disbursement of retirement benefits such as Gratuity, insurance, Leave encashment and disbursement of pension?  

PIO's reply- The procedure for disbursement of retirement benefits is that the papers are forwarded to the respective DDE, who in turn forwards to the respective PAO, who makes the payment.  After disbursement of the benefits, Leave Encashment is calculated at School level as & when the Service Book of the employee is returned by the PAO.


3. Name and Number of teachers/principals retired during the last five years from 01.01.2004 to 31.12.2008 from BR Mehta Vidya Bhawan Senior Secondary School Lajpat Bhawan. 

PIO's reply- Name of the teacher/Principal who retired during the period 01/01/04 to 31/01/2008 are detailed below:-


Sl No


Date of retirement

Date of payment of DCRG & Pension


Mr RS Dass




Mrs Kamlesh Sharma




RK Gupta




Mrs Satish Narang




JB Singh     




Mrs Sushma Lamba




4. Number of days taken by school administration in paying their retirement benefits including PF, Gratuity, insurance, Leave encashment and disbursement of pension.  

PIO's reply- School Administration sent the papers for the payment of retirement benefits to Department of Education in time for further procession.  School Administration cannot comments on the numbers of days taken by the DDE/PAO.  In this case, School Administration forward Appellant's papers to DDE on 13 November 2008 after fixation of the Pay as per VI Pay Commission norms.


5. What is the maximum limit for paying retirement benefits? 

PIO's reply- We cannot Comment.


6. Whether the time taken by the school administration in each case was according to the prescribed rules.  If not, who is responsible for the delay in each case?       

PIO's reply- Time taken by School in each case is as per norms.


7. Whether any action has been taken by the school administration or by the concerned office against the delaying officer/staff.         

PIO's reply- There has been no delay on part of School Admn., hence no action was required.


Not satisfied with the PIO's reply, the Nishchints filed their first appeal. In the appeal, they stated....

"Regarding Query no. 1- Daily progress report of Appellant's file has not been sent to the Appellant.

Query No. 2- Provide suitable reply of the question.

Query No. 3- There has been a delay of two months and 17 days to up to six month in each case as indicated in reply at query no. 3.  If this be the reply then why after 106 days of Appellant's retirement dues have not been paid.  There is a delay either in the office of deputy director of education (South) or there may be some corrupt practices going on in PAO for unnecessarily harassing the retired teachers/staff for getting their retirement dues…..

Provide the requisite reply."


There was no reply from the First Appellate Authority (FAA) for over a month. After this, the Nishchints approached the CIC with their second appeal.


During the hearing, Mr Gandhi, the then CIC, noted that the appellant had submitted the RTI before all the PIOs and the deputy director of the education (South). The PIO should have answered queries 5 and 7 but failed to do so, while the school has supplied the information on the balanced points, he said.


He added, "The Appellant is rightly agitated since she has been made to run from pillar to post to get her legitimate retirement dues. It is a sign of complete insensitivity and lack of basic courtesy towards an employee who has served for a long time and on retirement has to go begging from pillar to post to get her legitimate dues."


While allowing the appeal, the Commission then directed the PIO and deputy director of education (south) to provide the information on points 5 and 7 before 23 July 2009.




Decision No. CIC/SG/A/2009/001320/4016

Appeal No. CIC/SG/A/2009/001320


Appellant                                           : Nishchint



Respondent                                       : Lalita Kharabanda

                                                            Principal & PIO

                                                            Balvantray Mehta Vidya Bhawan

                                                            Sr. Sec. School of Servants of the

                                                            People Society (Delhi Branch)

                                                            Lajpat Bhawan, Lajpat Nagar IV,

                                                            New Delhi-110024


Our Stock Performance Report

Our stock picks of 2012 have beaten the Sensex handsomely. Here is our report card

Premium Content
Monthly Digital Access


Already A Subscriber?
Yearly Digital+Print Access


Moneylife Magazine Subscriber or MSSN member?

Yearly Subscriber Login

Enter the mail id that you want to use & click on Go. We will send you a link to your email for verficiation

We are listening!

Solve the equation and enter in the Captcha field.

To continue

Sign Up or Sign In


To continue

Sign Up or Sign In



The Scam
24 Year Of The Scam: The Perennial Bestseller, reads like a Thriller!
Moneylife Magazine
Fiercely independent and pro-consumer information on personal finance
Stockletters in 3 Flavours
Outstanding research that beats mutual funds year after year
MAS: Complete Online Financial Advisory
(Includes Moneylife Magazine and Lion Stockletter)