Consider the following statements regarding river engineering structures:

Explanation

1. Levees are built running parallel to the direction of river flow. 2. Spurs are constructed parallel to the river's flow. 3. Levees are built perpendicular to the river flow. 4. Spurs are constructed perpendicular to the river flow. The correct pair is (1) and (4) because levees run along the river flow, while spurs are designed transverse to it.