The area of Berrús, occupied by the Republican troops from the same day 25 of July, was a position conceived with a double objective: to defend the bridgehead of Riba-roja d'Ebre and protect the rear of the Pobla de Massaluca plateau.

The trenches of Berrús meander through the upper part of a steep ravine to control any access from the Riera de Berrús or the old road from Riba-roja d'Ebre to the Pobla de Massaluca (nowadays, road TV-7411). For this reason, the trench follows the classic zigzag design, but its depth is very variable, and has the most strengthened and advanced points in the shooter shafts with range of shot on the possible accesses. The defensive system was complemented by a secondary trench surrounding the higher elevation and protected the rear of the main trench.