While flooding in the Amite River Basin has always been an issue, studies beginning in the 20th century have documented significant basin flood events in 1921, 1928, 1942, 1947, 1953, 1957, 1962, 1964, 1967, March 1973, April 1977, April 1979, April 1983, August 1983, October 1985 (Hurricane Juan), January 1990, January 1993, January 1994, June 2001 (Tropical Storm Allison), and September 2008 (Hurricane Gustav); and of course, the April and August 2016 floods. 1979 was the flood of record in the ARB until the April 1983 flood, which was in turn eclipsed by the August 2016 flood, and then followed by the May 2021 flood.
Five of the floods in the Amite River Basin between 1973 and 1990 are characterized by USACE as major floods. 29 Prior to 2016, based on the Amite River crest elevation at Denham Springs, the most severe floods were those occurring in April 1983 (41.50 feet, 112,000 cfs peak discharge), April 1977 (41.08 feet, 110,000 cfs peak discharge), January 1990 (39.88 feet, 96,700 cfs peak discharge), June 2001 (39.34 feet, 82,700 cfs peak discharge), and January 1993 (38.15 feet, 81,900 cfs peak discharge).
Extensive flooding occurred in the ARB due to heavy rains that occurred between April 5 and April 8, 1983. Flood stages reached the highest levels in recorded history (at the time) along the Amite and Comite Rivers. Total rainfall for selected sites in the contributing watershed were reported as 14.04” in Clinton, 13.51” in Amite, 10.36” in Baton Rouge, 9.29” in Denham Springs, and 7.04” in Port Vincent.
About 5,300 homes and 200 businesses were flooded. 357,850 acres were inundated, and damages totaled $171 Million. Governor Treen declared 11 parishes disaster areas and formally requested Federal aid from President Reagan for residents of these parishes. Ultimately, Ascension (78,400 ac, $20.3 Million), Livingston (136,750 ac, $83.8 Million), and East Baton Rouge Parishes (55,000 ac, $65.2 Million) suffered the most inundation and damages, and were determined eligible for Federal Aid. Comparatively minor damages were suffered in Iberville (13,050 ac, $26,300), St. James (38,700 ac, $23,100), and St. John the Baptist Parishes (35,950 ac, $180,000).
By acreage, most of the inundation was suffered in the Blind River (115,750 ac), Amite River (82,400 ac), Colyell Creek (42,350 ac), New River (31,700 ac), and Comite River (25,000) stream basins, with lesser areas of inundation in the Grays Creek (15,800 ac), Hurricane Creek (3,000 ac), and other stream basins. By dollar amount of damages, however, the most damage was suffered in the Amite River ($56.6 Million), Grays Creek ($27.0 Million), Hurricane Creek ($25.9 Million), Comite River ($17.0 Million), Clay Cut Bayou ($8.5 Million), New River ($8.3 Million), Colyell Creek ($6.6 Million), and Manchac ($6.3 Million) stream basins.34 USACE reported flood damages in Louisiana for 1983 to be $651 Million.
Hurricane Juan. Hurricane Juan became stalled along the Louisiana coast for several days, producing extremely high wind-driven water levels in Lake Maurepas, reportedly above 6 ft NAVD88, and 6-day rainfall totals of five to eleven inches throughout the ARB. Significant flooding occurred in the coastal wetlands and margins. Upstream portions of the ARB were largely unaffected
Tropical Storm Allison. Tropical Storm Allison stalled over the region, with 7-day rainfall totals of 19.66 inches in Baton Rouge; 14.07 inches in Denham Springs; and, 23.29 inches in Ascension Parish. The 7-day rainfall totals in parts of the lower ARB were considered a 100-year precipitation event. Due to a significant drought and very low soil moisture conditions present prior to the event, flood conditions in the upper and middle ARB were not as extreme
Significant flooding occurred in the ARB due to heavy rainfall. Flash flooding set records with historic rainfall and river crests damaging at least 12,000 homes in the state. The March 2016 peak on the lower Comite River did not coincide with basin-wide heavy rains, and significant backwater flooding did not occur in the ARB
Catastrophic flooding occurred in the ARB (as well as other areas of the State) due to heavy rains from a slow-moving low-pressure weather system that occurred between August 11 and August 14, 2016. Rainfall exceeded 20” over a 48-hour period across a swath of East Baton Rouge, Livingston, and St. Helen Parishes, exceeding the 500-year storm. Areas around Baton Rouge received rainfall in excess of 24” over multiple days, with as much as 31” recorded in Watson, northeast of Baton Rouge. The Comite River, Amite River, Tickfaw River, and Tangipahoa River all rose to record heights. The rainfall led to widespread flash flooding and record river flooding, breaking many records previously set by the April 1983 flood. August 2016 was the wettest month on record for Louisiana, with a statewide average of 12.9”, topping the previous record of 9.71” set in August 1940.
Governor Edwards declared a statewide state of emergency and President Obama declared a major disaster in 20 parishes. Huge numbers of homes and businesses flooded that had never seen water before, including many outside of the 100-year flood plain. 13 deaths were reported, many roadways were closed, and cellular communications networks were disrupted.
Statewide, over 109,000 housing units were flooded: 77,000 owner-occupied homes; 22,000 renter-occupied homes; and 10,000 vacant units. Housing damage was most severe in East Baton Rouge (41,000 housing units) and Livingston (38,000 housing units), with 74% of the housing stock in Livingston Parish experiencing flood damages. The flooding caused $3.8 Billion in residential housing damages and nearly $1.3 Billion in contents losses, with $1.3 Billion occurring in Livingston Parish and $1.0 Billion in East Baton Rouge Parish. Over 90,000 automobiles were damaged, with almost $380 Million in damages.
Statewide, over 6,000 businesses were flooded, and 19,900 businesses were disrupted. This disrupted 278,500 workers, close to 14% of the Louisiana workforce. The vast majority were in East Baton Rouge Parish, with 8,000 businesses and 143,700 employees disrupted, with Livingston and Ascension also heavily affected. Economic losses were over $1.1 Billion, structural and equipment losses were $850 Million, and inventory losses were over $1.4 Billion. Once again, the vast majority of the damages were in East Baton Rouge Parish, with Livingston and Ascension Parishes also heavily affected. The flooding also caused over $110 Million in agricultural losses.
Amite River Basin Drainage & Water Conservation District
3535 S. Sherwood Forest Blvd, Suite 135
Baton Rouge, LA 70816