Three Rivers WMA to Simmesport - Red and Atchafalaya Rivers

16.1 miles, 4.1 mph avg
This trip began between the Auxiliary Control Structure and the Low Sill Control Structure. Accessed via Hwy 15 at the south end of the Low Sill Control Structure, turned onto an unnamed but well maintained gravel road atop a levee. Proceeded 1/2 mi to a gravel and riprap boat launch ( 31.0691478, -91.6015339 ) which included a portalet. Ample parking and most attendees seemed commercial fishers. A blank low angle water line to launch from at high water level.
Proceeded 2 miles down the flat with imperceivable water flow in the Outflow Channel to the confluence of the Outflow Channel from the Sidney A. Murray Jr. Hydroelectric Station. The current really began here and would only increase during the remainder of the trip. This confluence like the next and also the bridge pylons on this trip made noise and or were loud. There was nothing to fear about the current and the whirlpools. The small sport or commercial motorboats began to appear and the current really took off here.

Paddled 5 more miles to the Red River confluence. This was a highlight of the paddle. Rushing but flat noisy water generating whirlpools. Began looking for a rest spot in this area but noticed only steep banks or no banks due to high water. Got close to the bank and after two tries found and pull out and rested in perfect ambient low 70's temp conditions.

The next 4 miles were to the confluence with the Old River Lock Outflow Channel. No confluence turbidity was encountered as the Channel has no flow. We only experienced seeing from a long distance, one pushboat.

The last 5 miles of the trip we hardly paddled. We rode the in the big middle current, no other traffic, hardly paddled and were cruising along at over 4 mph. This leg was also unique in that it seemed this was our own personal river and no worries. None until meeting the vertical pylons of both rail and vehicular bridges. Water was roaring around with a bulbiuous wave built on the upstream side. Downstream of the pylons were ample whirlpools and powerfull eddie's of which this author decided to play. I felt the power of the river there but interestingly and unexpectedly little fear.

Hugged the west bank tight after the last bridge so as to not miss the boat launch pull out. Current was close to 5 mph (guessing), distance only 0.5 mi south of the bridge and difficult to see because of tress, high water and the ramp is angled. Was asked for a third time where we're from, where we started and where we going, good times. Simmesport Atchafalaya River Boat Ramp

16 miles, 4.1 mph avg, High level and high flow water, cool air temps with low wind, no blinding sun, nominal water traffic, tailwinds abound and good fellow paddlers. Overall a really great big water paddling experience. Would do again 10/10.

All of the control structures are located within the Three Rivers WMA.
From the web:
The Old River Control Structure is a floodgate system in a branch of the Mississippi River in central Louisiana. It regulates the flow of water from the Mississippi into the Atchafalaya River, thereby preventing the Mississippi River from changing course. Completed in 1963, the complex was built by the U.S. Army Corps of Engineers in a side channel of the Mississippi known as "Old River", between the Mississippi's current channel and the Atchafalaya Basin, a former channel of the Mississippi.[1][2][3][4][5]

The Old River Control Structure complex. View is to the east-southeast, looking downriver on the Mississippi, with the three dams across channels leading to the Atchafalaya River to the right of the Mississippi. Concordia Parish, Louisiana is in the foreground, on the right, and Wilkinson County, Mississippi, is in the background, across the Mississippi on the left. Old River low-sill control structure discharging water into the Atchafalaya, May 2011

The Old River Control Structure is a complex containing the original low-sill[6] and overbank[7] structures, as well as the auxiliary structure that was constructed after the low-sill structure was damaged during the Mississippi River Flood of 1973. The complex also contains a navigation lock and the Sidney A. Murray Jr. Hydroelectric Station.[8]