Pennsylvania watersheds info table includes,
WRDS# - stream code number of the Water Resources Data System database for PaDEP.
The code is a 5 digit integer between 00000 and 99999. For example,
the WRDS# 00833 is the Schuylkill River. This code is used by PaDEP
bureau databases to reference named streams for any activity related
to streams, e.g. water-quality sampling, water-use surface-water withdrawals.
Codes can be found in the Pennsylvania Gazetteer of Streams.
Heirlevel - DEP identification of location stream in watershed waterway.
1-11 are possible values, the lower the value the larger the drainage area
for the stream.
Heircode - DEP coding of relative location of the stream in the overall stream network
of the watershed. The 15 digit number indicates the primary watershed and all
drainage basins that the stream flows through. Both heirlevel and heircode are
subject to changes as edits are made to the DEP stream files.
HUC - USGS hydrologic unit code number and is defined as a numeric value with an input
and output of eight. This attribute has been approved for use by all Federal
agencies as a Federal Information Processing Standard (FIPS). The 8-digit HUC
number has four specific codes within it: region, subregion, accounting unit,
and cataloging unit. For example, the HUC number 02040106 is translated as:
02 = Mid Atlantic region,
04 = Delaware River Basin subregion,
03 = Upper Delaware accounting unit, and
04 = Lehigh River cataloging unit.
By name, this example HUC is all drainage basins in the Lehigh River
drainage basin. Source of HUC codes is U.S.G.S. water supply-paper 2294
Pennsylvania Department of Environmental Resources & U.S. Geological Survey. 1989. Pennsylvania gazetteer of streams, Pa. D.E.R. 323 p.
Seaber, Paul R. 1987. Hydrologic unit maps. U.S. Geological Survey. Water supply-paper 2294. 63 p.
Note that Pa. DEP and ERRI are working on an update to the stream codes.