2
WATER SCREENING TEST PROTOCOLS FOR STORMWATER MS4 GUIDANCE
USING COLORIMETRIC AND TURBIDIMETRIC TECHNIQUES
OVERVIEW
According the U.S. Census bureau the world’s population went from 2.5
billion in 1950 to 6 billion in 2000 and is on pace to exceed 9 billion by 2050.
We will soon have 3 times the global population we had only in 1950, and
with this growth comes enormous impacts on the surface of our globe. As
buildings and pavement expand so do our obligations to control stormwater
ef
fl
uents. Urban development creates new pollution, which can either be
washed or directly dumped into storm sewer systems, and ultimately into our
waterways and coastal areas. Storm runoff leaving developed urban areas is
signi
fi
cantly greater in inorganic content than runoff from the same area prior to
development.
Stormwater is typically de
fi
ned
as water that is created as a
result of a precipitation event.
This water may
fl
ow through
any path (gully, stream, conduit,
channel, etc.) or adjacent area
that is subject to over
fl
ow or
fl
ood water generated from
that event. This water passes
through a wide variety of natural
or arti
fi
cial environments, often
sweeping organic and inorganic
constituents into the watercourse
through municipal storm drain
systems. These environments
can include pipeline projects, construction sites, landscaped areas, agricultural
runoff, irrigation ditches, industrial sites, and a variety of other sources. In most
cases this material is eventually fed into a stream, river, or other waterway,
contributing to the overall pollutant load in that body of water.
While onsite sampling and offsite testing can be completed over the course
of a number of days, the source of this outfall continues to contaminate the
watercourse with both inorganic and organic constituents during subsequent
precipitation events. A means is required by which to screen the outfall to
potentially determine its source, the contribution it is making to the pollutant
load, and the proper course of action to take.
Instrumentation and reagent systems are currently available to make
measurements necessary to provide a preliminary screening of the out
fl
ow, and
determine whether it is contributing to the overall pollutant load as it relates to
inorganic constituents. In many cases these measurements can be made near
the source, using handheld instrumentation and test kits, which may provide
some indication as to the source and content of the out
fl
ow, or provide some
indication of what additional testing is required.
