WHY THE ROCK SHELTER HAS BEEN BUILT...
The rock shelter was constructed to capture and deflect the almost continuous rockfall from the cliffs above the gorge, this has been an issue since the roads original construction in the 1860s. This issue was exacerbated during the 1994 earthquake when considerable amounts of rock debri blocked both the highway and dammed the Otira River. The Reid Falls aqueduct was constructed to prevent flooding of the highway during heavy rainfall events.
The roof of the rock shelter is lined with thick foam pads to absorb the impact of large rocks. It has subsequently been filled by "fines" and scree that assists in the deflection of landslide material into the gorge below.
The Reid Falls aqueduct has been modified since its original construction with a vertical screen to prevent strong winds blowing the waterfall back onto the highway. This was a larger issue in winter when the water froze to the highway surface.