Union soldiers at work on Grant's canal opposite Vicksburg.
From a wartime sketch.

The Bayou Expeditions: Grant Moves Against Vicksburg— and Fails (continued)

DUCKPORT CANAL. A similar effort to turn Vicksburg's left flank was essayed by cutting a canal at Duckport, between Milliken's Bend and Vicksburg. By this avenue it was hoped vessels might leave the Mississippi above Vicksburg, pass through a series of circuitous bayous and emerge again on the Mississippi 20 miles below the city. The route was laboriously opened for navigation and one small steamer safely passed to the river below. Then the level of the river fell and blocked the Duckport attempt.

LAKE PROVIDENCE EXPEDITION. While the canal work was in progress, McPherson's Corps was assigned the opening of the Lake Providence route. The objective of this activity was the turning of Vicksburg's left flank by passing southward through the Louisiana waterways to reach the bluffs below the city. A canal was cut to provide entrance from the Mississippi into Lake Providence, 75 miles above Vicksburg. From Lake Providence a route was surveyed through the labyrinth of bayous, lakes, and rivers by which a fleet might emerge again on the Mississippi 200 miles below the city and move on Vicksburg from the south. While presenting great difficulties to navigation, the entire 400 miles would be safe from enemy action. By the end of March 1863, McPherson's men had almost cleared the route for navigation. The dredging of shoals and the sawing off of trees far enough below the water to permit passage of the transports proved the most severe obstacles. Before this long and extremely difficult route could be completed, however, other, more likely, plans were formulated, and the Lake Providence expedition was recalled.