wayne, where does the overflow from your swale go? Could it be the swale needs to be larger to infiltrate more water? If the swale overflows right away, it isn't going to be able to infiltrate much water. Rain harvesting earthworks are generally sized for the large events - so if you get a lot of rain all at once (like we sometimes do here) swales and basins need to be large or more numerous. Otherwise the water just runs off the land.
Apparently it can take years for the water table to be recharged by these structures, so we aren't likely to see dramatic changes any time soon, like springs appearing downhill or a constantly running creek (what I dream about!)