Questions and Answers on the Specification for the National Bridge Inventory
Except for any cited statutes or regulations, the contents of these Q&As do not have the force and effect of law and are not meant to bind the public in any way. These Q&As are intended only to provide information regarding existing requirements under the law or agency policies.
Topic: SNBI Section 4: Features (S4F)
QS4F-1 For Item B.F.01 Feature Type, when are more than one waterway features reported (and all associated items for that feature) and when are both a waterway feature and relief for waterway feature reported?
AS4F-1 A W## - waterway or a F## - relief for waterway feature type should be reported when a bridge spans over water. This applies whether the water source is perennial or intermittent, including if flow exists only during flood stage. A W## feature type is reported for each unique waterway spanned by the bridge. A bridge that spans a single unique waterway and/or its associated floodplain, will have a single feature reported. Also, a bridge that spans multiple channels or branches of the same unique waterway will have a single feature reported. A bridge that spans more than one unique waterway, although very rare, will have multiple features reported (i.e., W01, W02).
A F## feature type is reported for relief bridges that provide waterway opening for flow only during flood stages and furnish additional hydraulic capacity.
A W## and separate F## feature type would be reported only when the bridge spans a waterway and a separate relief channel is constructed in the floodplain; this would be a very rare condition.