I have wondered if converting a pool into an elaborate water feature such as a pond with a waterfall and some surrounding vegetation and rock features would be an alternative to the cost of complete dismantle/removal.

wetlands maps are inherently unreliable. if you want to be sure, engage a biologist to perform a jurisdictional wetlands determination (this is based on three specific factors-hydrology, soils and vegetation). it is also possible the wetlands may not be federally-regulated but subject to state regulatory jurisdiction. your state may also have buffer areas that cannot be developed to protect wetlands.  

So if you decide to chemically kill all of your unwanted vegetation, then I would recommend buying offbrand concentrated glycophosphate for use in a pump sprayer and go crazy with it (while following manufacturers mixing instructions) but leave an unsprayed border of about 2 feet around your trees and use it on a calm day without wind or rain.  

While there are some great projects underway, most are very small scale - just a few city lots at a time.I've worked with one on the East Side and in addition to growign vegetables in the summer, they have a hoop house for year-round cool-weather produce, a lot with fruit trees, a lot with chickens and goats and they purchased the old, abandoned corner store and turned it into a community center with a library, computers and meeting area.

I throw all vegetable scraps, banana peels, eggshells, etc. into a plastic composter all summer long.

BUT they have no use for the huge vegetable garden area we have provided, but our old Italian tenant does grow a LOT of produce, God Bless him. 

Actually it is fermenting vegetables.

This house has a huge fenced yard with a vegetable garden.

You want a diversification of assets.... a few vegetables, beer, meat, snacks, water, milk, etc....Frank

Should there ever be a reversal in the State or Federal laws prohibiting such use the greenhouses would still be a very viable, albeit not as profitable from an ROI stand point, for the cultivation of vegetable and/or other plants that need year around environmentally controlled conditions.My thougt was that since it looks as though there's a real strong possibility that the Marijuana industry looks like it could be here to stay that expanding into commercial and reatail properties that lend themselves to this venue might be a prudent investment.