You may notice that there are practically no hills in Lee County. Therefore, there is not a lot of slope for the swales to convey the water quickly to the canals, rivers, pond and lakes. Because swales convey water by gravity flow, it is a common sight to see swales throughout Lee County at different depths. This explains in part why some driveways have pipes under them and some do not. Having a swale provides a place for the water to go, rather than flooding private property.
Swales also keep most of the water off the road which provides a longer life for the road.
It is not unusual for the swale to fill up with water during a rainfall. During a heavy rainfall, the water can fill up beyond the swale. Measure the amount of water in your swale just after the rainfall has ended. Then measure the amount of water in your swale 12-36 hours later. If there is a difference, you know that the water is running off and your swale is working properly.