REMOVE

1. rivers
2. telephone poles
3. hills
4. boats
5. 1936

WHAT

1. Grand Coulee Dam (dam) (1)
2. Visual works (hierarchy n … (1)
3. construction equipment (1)
4. construction sites (1)

More 

WHERE

1. Nespelem, Washington (1)

WHO

1. Still, Clyfford (1)

WHEN

1. Regionalist (American Sce … (1)