In the first few days after the torrential August rains, Brant Mitchell and his colleagues at LSU's Stephenson Disaster Management Institute took whatever flood information they could get.

Some parishes were able to pinpoint flooded neighborhoods through geo-located 911 calls and their own extensive mapping data, but others provided maps with inundated areas marked off with a highlighter.

Working on contract for the state, the institute's analysts churned out very early numbers — the floodwaters still lingered in some areas — to help land a presidential disaster declaration, the key to future federal aid. Their early estimate for structures that might have flooded in Ascension, Livingston and East Baton Rouge parishes alone was a shocking 127,273.

Four months later, an exact count of damaged homes and businesses remains an elusive figure. State, parish, business and local government officials have released a string of estimates that haven't always matched up with one another.

The figures put out range widely — 153,000, 115,200, 90,000, 146,000. The reasons for that are simple: they reflect different aspects of the flood at various times covering different regions and are calculated for different purposes.

But perhaps the most important factor is that there is no overriding reason for a government agency to nail down a total, global number.

One top state Homeland Security official suggested a hard count of all flooded homes and businesses just isn’t out there right now.

“You are not going to find an accurate number. There is not anybody out on the street that has counted each home that has flooded,” said Mark Riley, deputy director of the Governor’s Office of Homeland Security and Emergency Preparedness.

While state officials say they are waiting on tallies from the parishes to hone a final figure, probably months from now, Riley believes the number of households that registered for Federal Emergency Management Assistance aid is a good measure of overall impact.

Registrations for FEMA individual assistance, the key grant program for affected homeowners and renters, reached 153,132 through Nov. 27 in the Baton Rouge and Lafayette areas and elsewhere across the state.

“The reason I use that number is because I’m looking at the size of the event to compare to other events, and so that 153,000 gives me the size and complexity of this event,” Riley said.

But that figure doesn’t reflect just flooded homes. It also includes people who, while their homes didn't flood, still lost uninsured cars or other property. Also inflating the number is that it doesn't yet account for redundant claims made by different family members for the same home. Furthermore, the FEMA registration tally also excludes businesses, which must seek help from the U.S. Small Business Administration.

A count of flooded homes and business isn’t just a point of curiosity or a key factor for long-term planning. As former state disaster recovery chief Paul Rainwater notes, the number is the basis for how much special disaster money the state lobbies Congress for.

Complicating the issue is that the August flooding wasn't the only such disaster this year. In March, parts of north and south Louisiana were hit by rains that swamped thousands of homes and businesses.  

Gov. John Bel Edwards is seeking nearly $4 billion in funding for the August and March floods. Congress recently approved $1.25 billion of that aid — for a total of $1.68 billion so far — and is expected to approve more.

For that purpose, the state supplied Congress with estimates based on FEMA tallies of verified home damage, a figure that has reached about 112,300, with the August floods accounting for 90,679 of it. But that count excludes businesses and apartments.

Allison Plyer, executive director and chief demographer for the New Orleans Data Center, which has tracked the changes to New Orleans since Hurricane Katrina 11 years ago, said flood estimates often vary after a disaster as early tallies shift to homeowners applying for assistance, building permits and data collected from the field.

“At first, they go up as the data is being collected,” Plyer said. “And then, at least in the case of when they’re applying to the government for assistance, they do tend to go down in the final analysis.”

That matches what has happened here. Early estimates of flooded homes and businesses from various groups and agencies in the Baton Rouge area quickly ballooned to 145,500.

Now that reconstruction is well under way, that figure seems to overstate the damage in East Baton Rouge, Ascension and Livingston parishes, the epicenter of the August floods.

Take Livingston Parish, for example. Facing scenes of dramatic flooding in Denham Springs and Walker, local officials initially said 74 percent of homes may have taken on water.

Assessor Jeff Taylor now notes that while the estimate might apply to heavily flooded Denham Springs, it doesn't hold true for the parish as a whole, which he pegs closer to a still-staggering 55 percent.

Even at the parish level, numbers continue to vary depending on who is issuing them. 

According to figures released by the Ascension, Livingston and East Baton Rouge parish governments, a total of about 92,750 homes, businesses and other buildings were damaged by the flood. Numbers directly from the assessors for those same parishes, however, total 75,167.

The numbers are different in part because the agencies involved have different goals.

The parish governments, which handle building permits, are focused on homes that might have to be elevated or razed under federally mandated floodplain rules. The assessors are required by law to revalue flood-damaged homes and buildings for tax purposes. 

The numbers from the parish governments and assessors vary for a couple of reasons. One factor is that assessors are looking at parcels. Many parcels, such as duplexes or apartments, can include more than one home. Assessors might view that as one damaged structure, while parishes would view it as multiple damaged homes.

In East Baton Rouge Parish, regulations have shaped evolving estimates.

Early on, the city-parish estimated that 58,558 homes, businesses and public buildings flooded in August, but subsequent mapping analysis, debris collection data and information from inspectors in the field have lowered that figure to 48,383.

Justin Dupuy, the city-parish's building official, said contractors working with the city-parish and FEMA physically inspected all buildings flooded inside the 100-year floodplain, or about 23,200, to determine if they had to be elevated, demolished or moved.

But those inspectors did not examine flooded buildings outside the floodplain because regulations don’t require it, Dupuy said. The earliest estimates suggested 32,000 buildings flooded outside the 100-year floodplain, though that number is probably much lower.

Dupuy said that while building permits might pick up some buildings outside the floodplain — about 8,900 flood-related permits had been issued through Nov. 22 — structures that took less than 18 inches of water do not need them.

That standard means the least flooded homes, which are most likely to be outside the 100-year floodplain and were not counted by FEMA contractors, also won’t show up in permit information.

Dupuy said the city-parish has a good understanding of where the flooding happened, but a final number isn't imminent.

“At the end of the day, they may not have the full picture for another year or so. I think the best right now is to have a decent estimate,” Dupuy said.

East Baton Rouge Parish Assessor Brian Wilson relied on in-the-field inspections, FEMA data and maps, debris collection information and other data to find about 41,000 flooded homes and business that needed to be reassessed. Wilson said he expects the owners of flooded homes that weren’t reassessed will call to ask for lower bills once tax notices go out in January.

“I think that it’s pretty solid number," he said. "Again, there may be some out there I don’t know about. I don’t know how many, but I don’t think it’s going to be a tremendous amount we missed.”


Follow David J. Mitchell on Twitter, @NewsieDave.