The only thing I would add is that in 2009 we did a review of the application of the act, and that particular topic came up as a difficult situation for a lot of the departments to handle. How you do cumulative impacts is not very clear for them. Having said that, the agency has come up with guidelines, but it is still something that is bringing confusion for the departments that have to apply them.
On October 4th, 2011. See this statement in context.