ARKANSAS CONTROLLING

Anguilla Oak Grove 65 THE MIGHTY RIVER 61 Lake Providence Control structures on the are designed to preserve life through the river basin as well as provide a systematic response to alleviate possible Onward flooding during severe conditions. Three structures exist on the , and all have been called into service at least once: the Old River Control Complex, the Morganza Spillway and the Bonnet Carré Spillway. Old River Control Complex 3 INSET 1 Sidney A. Over bank This complex uses four structures to Murray Jr. structure distribute flows between the Mississippi Redwood Delhi Hydroelectric and Atchafalaya Station Mississippi River water diverted primarily rivers. The complex maintains a 70/30 20 Outflow channel though these two Red River flow distribution 17 structures into the Low sill between the Vicksburg Old Ri structure Mississippi and Upper ve Auxiliary 65 r structure Atchafalaya rivers, 27 R respectively, at Old River and can safely L Old iv o w er er pass 620,000 cubic feet per second of water from the Mississippi to the 61 Atchafalaya Mississippi River Atchafalaya. 4 River

Morganza Spillway INSET 2 The Morganza Spillway is designed to Port Gibson r e transfer flows from the Mississippi River v A i into the east Atchafalaya tc R r h i e a sissipp Basin. The Mississippi Sicily Island iv f s Mississippi River i R a Levee i p l River Commission 15 ip a M water diverted s y is a through control president would normally s R s make a decision to open i structure and into i v M e the spillway the control structure Fayette r 28 Melville Morganza when flows reach 1.5 61 million cubic feet per second at Red River Landing, just above the Morganza 84 structure, with data indicating that the Vidalia Natchez river will continue to rise. This situation 84 Morganza occurred May 14 when the control Spillway structure was opened for only the second time. The previous time was during the Lottie 1973 when the structure was MISSISSIPPI 190 partially opened to lower river stages 33 and relieve pressure on the Old River Krotz low sill control structure. Springs 61

INSET 1 Woodville Bonnet Carré Spillway 24 INSET 3 Lake This spillway is designed to divert water 1 Pontchartrain from . The spillway was 10 opened May 9 and is expected to remain Simmesport Red River open for two to four weeks to reduce Landing pressure on the main levees and to 1 Levee reduce the river current from the spillway INSET 2 Clinton 61 southward toward New Orleans. 10 Mississippi River Since 1929, the spillway has been St. Francisville water diverted 63 operated nine previous times, 19 through gates into diverting river water into Lake 61 Morganza 67 the spillway to Pontchartrain and eventually into Melville New Roads the . The spillway 71 can be operated when flows reach 10 Mississippi River 1.25 million cubic feet per second and

A are expected to rise. The spillway was Lottie t Livonia c 16 last operated in 2008. Opelousas Krotz h 190 a 190 Springs f Denham a Hammond l a Baton Rouge Springs 190 y 43 a Port Allen 12 49 Covington MISSISSIPPI R 61 36 i v e r

55 10 Bay St. Louis 10 10 22 Plaquemine 44 Lake Slidell Lafayette 1 Gonzales Maurepas Lake 90 INSET 3 10 90 Pontchartrain 70 10 11 Donaldsonville 61 LaPlace 1 New Iberia 61 New Orleans 3127 Chalmette Delcambre Napoleonville 90 182 20 90 Belle Chasse Franklin 70 Thibodaux 182 1

90 Morgan 90 23 N City Houma Larose Mississippi PointeRiver a la Hache

57 1 Chauvin Golden Meadow

Venice Grand Isle

River crests now compared to other great Port Fourchon in the Lower Mississippi River Valley Gulf of Mexico STATION 1927 1937 1973 1997 2008 2011 Cairo 56.40 59.51 55.67 56.20 53.83 61.72 Memphis 45.80 48.70 40.48 42.00 38.00 47.90 Vicksburg 56.20** 53.20 51.60 49.10 51.00 57.50* Red River Landing 60.90 58.99 58.20 62.30 60.69 65.50* Baton Rouge 47.28 44.50 41.60 43.70 43.09 47.50* New Orleans 21.00 19.10 18.40 16.90 16.88 19.50*

*Forecast crest **Would have been 62.2 if levees had held Sources: Mississippi River Commission, U.S. Army Corp. of Engineers, Louisiana Department of Transportation and Development Advocate graphic