First off, that's like asking your building inspectors "what can I do without a permit". Governments are dearth to "help out" like that. Even if you know a guy, the boundaries typically aren't binding until a survey has been done the state or municipality has a approved it and it's been registered with whoever handles land stuff in your jurisdiction.

Second, most states that regulate wetlands beyond the federal minimum adopt some sort of absurd expansive standard far above what the feds want. It's complex and varies by state. Sometimes there's a square footage minimum, sometimes there isn't. There's also "gotchas" where manmade areas can become wetlands if they are let to be that way too long, so like farmer Johnson can absolutely get screwed by his grandfather's bright idea to make all the drainage converge in one spot 40yr ago. Sometimes there are exemptions, sometimes not. There's huge variation by state and some states allow local governments to enforce rules above and beyond the state ones.