I pretty much have a constant marsh in my backyard (and front yard and ditch out front), but some here might be interested in redirecting rainwater away from the house and foundation, so this could be a good idea, especially if you're interested in attracting butterflies and other wildlife, to your yard. http://www.nwf.org/How-to-Help/Garden-for-Wildlife/Gardening-Tips/Create-a-Backyard-Marsh.aspx
This is a very good idea because anything that is recycled means conservation. However, I cannot imagine having water like a pond or a marsh unless there is fish like guppy that will prevent the breeding of mosquitoes. We saw that in Thailand where marshes were converted into gardens with elevated beds that are planted to vegetables and trees. Now, with too much rain, we have a natural marsh in our extended garden. That water was there since 3 days ago due to the daily rains. So expect the mosquitoes in a day or two.
Yes, that's exactly what happens here. I would love to have a fish pond in the yard, but there are too many predators here. I guess if the depth would enable the fish to escape it might be o.k., but otherwise, the raccoons and other animals could catch and kill the fish, which is what happened with my patio pond. The neighborhood sprays here, because the area tends to be marshy, plus we have the gully, creeks, and woods, so there are always lots of mosquitoes.
We have had an unusual amount of rain in our area but so far no more than normal amount of mosquitoes. I have taken the house plants that I usually set out for the summer back into the house because of the rains and keep the containers that collect rain water empty to avoid the growth of mosquitoes.
That's probably a good idea, @Pat Baker. I don't have a cover over my balcony, and it's strange, after a heavy rain, some of the pots will be filled to the top, and others barely have any water in them. I was just out feeding the stray cats and saw a tiny toad in their water dish. I guess the ground is starting to dry out, so it was looking for some moisture. I've found frogs and toads in the pots that I leave down on the back porch, they seem to like being in the water, even when it's deep.