I live on the west coast of California on a sand dune. We are at the top of one with the road below. Horses just found good homes, so I would like to turn the pasture into swales. Do I think contour and then place swales or do I think of runoff and create ways to control that so it goes deeper into the sand? On this property, the only places with plants are the places with a water source nearby, otherwise there are only weeds. Can I create miniswales to keep water uphill to where I have plantings. Since my governator won't support water retention basins, I think private basins may be the only answer.
Swales should control runoff, and soak the moisture into the ground. Keep in mind that swales should primarily be tree growing systems, so if you plan on keeping your pasture without adding trees you might want to look into something along the lines of keyline plowing, cover cropping, mulching, applying compost teas, and reseeding the pasture.