@bythewell - Another possibility is to just have a swampy area in general and plant the right kinds of plants to deal with it. With a few strategically placed rocks, it can actually be quite pleasant and a valuable part of local diversity. It can also help to clean runoff from your roof or concrete paths.
The only problem is that it can also lead to trouble if you live in an area where mosquitoes are likely to breed and if there's enough water to make little pools. Any kind of standing water will increase their populations and that's rarely something you want to encourage. But most wetland plants will grow well in damp soil and don't need pools of water, so it's possible a bit of land drainage is all you'll need.