After widespread flooding, many question how well turf will survive. Turf injury from flooding depends on water temperature, species, duration of submergence, and depth of submergence. Turfgrasses can withstand submersion for up to 60 days when water temperatures are 50 degrees or less. Injury is increased under stagnant water compared to moving water, and injury also increases with depth of water. Of the cool-season turfgrasses used in IN, creeping bentgrass is the most tolerant of submersion, Kentucky bluegrass being less tolerant, and annual bluegrass and perennial ryegrass being the least tolerant to submersion. Additionally, silt and flood remnants like corn stalks, trash, and branches can further exclude light weakening a turf stand. I would doubt if we see much direct damage from the recent flooding, but it is still important to remove silt and trash as soon as feasible to allow light penetration.
A waiting game
The real measure of flood or ice damage cannot be made until spring green-up. If large areas aren’t greening up, introduce more seed with power seeding or aerification followed by drop seeding. Avoid early applications of preemergence herbicides in case you’ll need to seed. Post-emergence crabgrass herbicides like quinclorac (Drive and others) and dithiopyr (Dimension and others) can be used after the seedlings emerge if areas are just thinned by winter damage and not killed, applying 0.75 lb N/1000 ft2 in mid-April, Mid-May, and mid-June will help improve density. Do not use rates higher than this because you may encourage too much vertical growth at the expense of root growth and summer stress tolerance.
More information on general turf management is available at our web page at http://www.agry.purdue.edu/turf/. Specific information on flood damage can be found in the turf tips archives athttp://www.agry.purdue.edu/turf/tips/2004/flood618.htm