Assertion: natural spillway | /r/HasProperty | lined with riprap
Facets:
value: often
type: TEMPORAL
Source sentences:
text: New natural spillways are vulnerable to erosion, so they are often lined with small stones or riprap.
text: When natural spillways are new they are most vulnerable to erosion, so they are often lined with small stones or riprap; even bricks laid like paving have been used for reinforcement.