The Potomac study also showed that land use is an important factor in water quality.
(The Potomac study; showed; that land use is an important factor in water quality) Context(The Potomac study showed,List([0, 29))):(land use; is; an important factor in water quality)
The Potomac study showed,List([0, 29))
The Potomac study land use
showed is
that land use is an important factor in water quality
an important factor in water quality