How does water affect mass-movement processes? Choose all that apply. How does water affect mass-movement processes? Choose all that apply. When only enough water is added to make the sediment on a slope slightly damp, the sediment sticks together and resists downward pull. Water fills the pores between sediment, destroying the sediment's overall cohesion. Complete saturation of sediment on a slope makes the sediment more resistant to the force of gravity. Water added to sediment on a slope merely passes through and washes downslope, whereas the sediment remains in its original place on the slope. Water adds weight to the material on a slope.