U.S. Department of the InteriorU.S. Geological Survey

Conflation Issues in New Jersey

David AndersonUSGS Technical POCMid-Continent Mapping CenterNational Geospatial Technical Operations CenterRolla, MO

Status

New Jersey DEP has local level data (1:4800) collected and is conflating the attribute information from the 1:24,000

Employed a contractor to complete the work in January 2009

NJDEP prepares data prior to giving to the contractor by sub-setting smaller areas from a downloaded subbasin and running the NHD Flow Check utility

Contractor completed a pilot project March 2009

Pilot Project Issues Found

Features in NHD Status table existed in edited dataset

Pilot Project Issues Found

Reachcodes assigned to non-reachable features (State prerogative – to assign reach); however, in this case the state did not want reaches assigned

Pilot Project Issues Found

Reachcode exists as OldReachCode in NHDReachCrossReference – must retire entire reach and resume confluence to confluence rules

Pilot Project Issues Found

Lake/Pond features > 10 acres in size get a new reachcode along the artificial path

Pilot Project Issues Found

Incorrect assignment of reachcode – underlying feature rule:

Connector and Artificial path may maintain the reachcode adjoining the feature, all other changes in feature type require a new reach code