How can swales work with fractured limestone under topsoil (Missouri)?

Newbie here. When trying to explain the benefits of swales on our small farm to my husband, he brought up a 'yabbut'. Everything under this part of Missouri is limestone - broken up limestone, it seems, so in trying to allow the water to sink in and sub-irrigate out in front of the swale, he says it will just fall through the cracks. There is some evidence of this near our big pond which was formed with a berm. It is only green a very short way out from the berm. Love the idea of trying to keep water here, especially with the droughty hot summers we get, but how do we work with this peculiarity? He probably won't want to put the large sum of money needed for equipment rental, etc into this without assurance that we're going to get a good benefit from it. Ideas? Thank you!

Do you have any clay? A little clay to line the swale and slow the infiltration will allow it to charge the ground.

Consider mini swales on contour and lots of organic matter to act like a sponge (think of "hugel beds") while slowing the water infiltration. Cover crops all over to reduce evaporation.