Hundreds of miles inland from the Gulf of Mexico, Arkansans were making their own hurricane preparations on Wednesday (August 29) in anticipation of the rain and winds Isaac’s remnants might bring and the memory of a pair of 2008 storms.

In August 2008, the remnants of Hurricane Gustav crawled slowly north, dumping more than 11 inches at Hamburg. Hurricane Ike, which followed in September, dumped 1-3 inches in the western two-thirds of Arkansas, with some locally heavier amounts. Both storms flattened crops and damaged buildings and other structures.

In northwest Arkansas, Washington County fair officials on Wednesday “began assessing the ‘what ifs?” said Berni Kurz, county Extension staff chair. “We are assessing the barns for possible flooding problems and we are correcting these wet spots and all tie-downs on tents are being checked as well.

“Fortunately, by Friday, we will have completed the livestock shows and events that draw the big crowds,” he said. However, “If we have rain all day Friday, it will shut down the midway and Friday night is typically the busiest night, so Isaac has the potential to hurt the Washington County Fair financially.”

Flash flood watches have been issued for much of Arkansas, effective into Friday night.

Anticipating runoff

With Isaac’s serpentine path and the heavy rain it is dumping on the gulf coast, it’s difficult to predict how much water Arkansas may see this week. Though small and slowed by air resistance, raindrops still pound the ground at about 9 meters per second -- around 20 miles per hour.

Hal Liechty, professor at the University of Arkansas at Monticello and part of the Arkansas Forest Resources Center, said, “The amount of runoff is determined by the difference between the rate of precipitation and the rate it’s being absorbed by the soil, and given our dry conditions, it should soak into the soil rapidly.” 

In areas where there’s bare soil and a very dry crust has formed, water may take longer to soak in. “But if there’s some kind of cover crop like trees or grass, crusts are less likely to form,” he said. ”Vegetation also helps slow the impact of rain on the soils.”

Water hits the leaves of trees or crops and begins drips through the canopy of the vegetation, which “lowers the velocity of the water and helps infiltration” to the soil.

Down the drain

During the drought, many drains went ignored, but now they need attention, said John Pennington, Washington County Extension agent who works with urban storm water issues.

The City of Magnolia this week asked residents to check storm drains for blockages.

“In cities, retention basin outlets should be checked to make sure they’re not clogged; and in both cities and rural areas, box culverts should be cleared of leaves, grass clippings, trash and wood,” he said. “Unsecured items should also be put away to ensure they don’t wash into waterways.”

Any property or materials stored in flood plains should be moved to more secure locations to prevent property damage and contribution of trash into waterways.

Pennington also said construction crews should be sure “silt fences, filter socks and hay bales placed at the edge of construction sites and storm drains are checked to make sure they will function properly to prevent pollution from running into the water ways.”

For landowners with ponds, Nathan Stone, Extension fisheries specialist based at the University of Arkansas at Pine Bluff, advised making “sure to clear away any debris within the pond auxiliary, or emergency, spillway channel or on the drainpipe trash guard before the storm arrives.”

For flood preparedness see here.

Tornado preparedness tipsheet available here.