D - Drain dug to intercept the water table or
potentiometric surface to either lower the
groundwater level or serve as a water supply.
E - Excavation.
H - Sinkhole.
I - Interconnected wells, also called connector or
drainage wells; that is, a well interconnected via an
underground lateral.
M - Multiple wells. Use only for well field consisting of a
group of wells that are pumped through a single header and
for which little or no data about the individual wells are
available.
O - Outcrop.
P - Pond dug to intercept the water table or
potentiometric surface.
S - Spring (used only on spring schedule).
T - Tunnel, shaft, or mine from which groundwater is
obtained.
W - Well, for single wells other than wells of the collector or
Ranney type.
