Every farm must have water to function. There are many quite different solutions to this problem from the point of view of crop-raising, from overhead sprinklers to underground drip irrigation, from canal irrigation to raised beds, from biodynamic double digging to hugelkultur. Each of these methods has its own positives and negatives, more importantly they each have a particular environment in which they are the best choice for that space. In areas where there is a kind of rolling topography and a good proportion of clay in the soil, the farm pond shines due to its ease of engineering. Where you have a watershed of two or more acres, you can build a sizable pond. It can be as simple (not easy: simple) as building a straight line dam from one rolling hill to the next.