Plaintiffs have sufficient Article III standing to challenge EPA action affecting a state's rivers when they can establish concrete and particular harms arising from some subset of the rivers.
State's lack of filing is insufficiently clear and ambiguous to trigger the constructive submission of a refusal to file -- the question of agency obligation is therefore one for trial.
http://www.ca4.uscourts.gov/opinions/171430.P.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.