Regulations and Procedures: Can a Government Agency Be Sued for Having an Unreasonable Rule

I live in Colorado in an area that has a govt agency that is responsible for collecting a "fee" from people in a drainage basin to build a structure downstream that will hold water in the case of a 100 year flood and thereby remove a couple hundred acres of land from the FEMA flood plain and allow developers and local govts to benefit from the homes built there. My particular issue is with the criteria for having the fee waived(the legality of the whole project and charging the fee is another story). The agency has been forced to develop a policy for people that claim they should not have to pay the fee(like me) because they do not discharge water into the basin, the flood water is detained on my property, not by my choice though(for reasons that I will probably ask in another thread, nothing to do with this agency). The policy has criteria that they say are based on the county drainage requirements, but it turns out they are requiring 200% more volume of detention to waive the fee than the county requires for developers to build new construction. Question - Is it possible to sue the agency for having an unreasonable requirement? If they use the requirements in the county rules for developers I have enough detention on site, if they get to arbitrarily add "multiplied by 2" at the end of the paragraph then I don't.

Thanks for any info.

Regulations and Procedures: Can a Government Agency Be Sued for Having an Unreasonable Rule