The entrenchments behind you would have been shoulder height, rain would have been falling, and the mud here slick and slippery. You can see from the terrain how a Union soldier, moving along the valley and trying to keep from exposing himself to fire from the Confederate line extending to your right would have been naturally funneled to this position.
The monument on the left of the picture marks a second ridge. The other side of it was also shielded from Confederate view, but the moment they crossed the ridge they were exposed to fire. The monument marks where many Union soldiers died, coming out of the low ravine and into the hail of Confederate fire.
At this position, Union soldiers would have huddled in the mud and rain, before climbing onto or over the wall, to shoot at or engage Confederate soldiers in vicious hand to hand combat on the other side.
This view is taken from the Confederate side of the entrenchments, marked here by natural grass and protected with a rope barrier. This would have been lined with logs, shoulder height, with traverses every twenty feet so no one could fire down the line.
For a defending soldier, it would have been like being in a three sided, shoulder height roofless log cabin twenty feet wide, with Union soldiers vaulting over the top in the rain and mud and engaging you in hand to hand combat, or firing at point blank range.
As Confederate reinforcements moved up into this area, they were met by a steady stream of unseen Union soldiers moving up from the ravine beyond, and they would continually meet face to face behind this entrenchment for the next twenty hours.
Bodies and wounded stacked up layers deep, making it even harder to stand in the water and blood drenched mud.