Pascagoula River Stage at Merrill Will Exceed Flood Stage

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Horn Island and its southernmost barrier island depend heavily on the Pascagoula River’s unimpeded flow into the Gulf of Mexico for survival, providing nutrients, silt, and sediment downstream, benefitting habitats that take advantage of these resources.

Brown explained that should the Pearl River reach flood stage at Monticello, homes may become inundated, and residents may need to evacuate, necessitating their evacuation. High water levels could also close hunting seasons at Old River WMA near Poplarville and Shipland WMA in Coahoma County.

Flood Stage

Tropical Storm Isaac’s heavy rainfall is leading to flooding along local rivers. The Pascagoula River near Merrill is expected to surpass flood stage on Saturday morning and reach 22 feet of depth, while McLain’s Leaf River and Chickasawhay River at Leakesville could also reach or exceed their flood stages, according to the National Weather Service in Jackson.

Flood stages are set up at specific stream gauge locations to indicate when rising water levels begin to disrupt lives, property, or commerce significantly. They are assigned depending on both the assessment of particular impacts and the frequency of high-water events; these categories differ from the flood stages used to calculate insurance premiums in many states.

Flood Warnings should prompt those living in low-lying areas to prepare for evacuation, according to the weather service. When floodwaters reach or overtake roads, traveling by car is hazardous. Residents should also avoid riverbanks during these warnings.

A rain advisory remains in effect through Friday evening, and rainfall should begin to decrease after that point. While Pearl and other area rivers could still crest above their flood stages, damage-causing floodwaters should still stay below levels that cause widespread disruptions of homes and businesses. Weather Services will monitor river levels closely in anticipation of cresting.

Water Temperature

The National Weather Service anticipates the Pascagoula River at Merrill is forecast to break over flood stage Thursday and reach nearly 24 feet at its highest point Saturday evening, leading to flooding in Greene, George, and Jackson Counties at 20 feet; Plum Bluff is covered by water while Leakesville Bridge on State Route 63 remains closed to vehicles.

Rains from Tropical Storm Isaac have caused rivers in South Mississippi to rise and threaten flooding, according to a map provided by the National Weather Service. Many areas are still under flood warning until early next week.

The Pearl Rivers in Jackson and Monticello are forecasted to crest well above flood stage, though meteorologists expect the water will soon recede downstream and cause no extensive damage to homes or businesses. As a precautionary measure, several counties, including Jackson and Greene, have declared states of emergency due to flooding that has already forced evacuations; heavy rainfall is anticipated over the weekend.

Water Levels

Rivers swollen by recent heavy rainfall are expected to exceed their flood stages across South Mississippi, but most flooding should remain localized to areas adjacent to waterways, according to National Weather Service Meteorologist Thomas Winesett. He indicated that although the Pearl River could exceed the flood stage in Jackson, it’s unlikely to cause significant property damage or threaten life. He predicted it should crest around 26 feet next week. High water is also expected for the Leaf River near McLain and Chickasawhay River at Leakesville. Steele Bayou Control Structure land-side gauge in Vicksburg currently measures over 87 feet, which could force Sunflower (Delta National Forest) and Twin Oaks Wildlife Management Areas to close hunting seasons for deer and small game hunters if it reaches an acceptable level set by the state.

The Pascagoula River at Merrill is already one foot above flood stage and expected to crest five feet when it crests Friday morning, flooding roads including Smith’s Fish Camp Road in southern George County as well as Plum Bluff highway bridge in Greene County when reaching 24 feet of flooding.

Monticello is warning residents to evacuate as the river has crested 28 feet above flood stage, and officials urge those living in low-lying areas of Greene, George, and Jackson counties to move valuables away from the edges of their properties before the rising water reaches cresting point.

Oxbow

Oxbow lakes along the Pascagoula River are formed as a result of natural erosion processes on its banks. Over time, faster-moving waters on the outside of bends erode banks while slow-moving waters deposit sand and mud on their interior, eventually creating an oxbow lake within its thin barrier of landmass separating old courses of river channel from its new courses; within this thin barrier lies an oxbow lake area.

Horn Island, Mississippi’s southernmost barrier island, benefits from the unimpeded flow of the Pascagoula River into the Gulf of Mexico as its nutrients and sediment play an integral part in developing its beach, nearshore marine food chain, and shallow open-water areas that act as nurseries for various marine and estuarine aquatic species.

The Pascagoula River delivers millions of gallons of freshwater daily into Mississippi Sound (the area between Mississippi barrier islands and southern shore of state) known as Brackish water, which supplies estuaries with vital nutrients that make them one of the most productive habitats on earth. Furthermore, this rich resource also supports prehistoric fish such as the Gulf Sturgeon, which can grow up to 9 feet in length and require healthy river systems in which to mate and lay eggs.