The growth of some Spanish eities has created the need to develop urbanistic projects in its surroundings, on lands that in many cases have been affected by the activity of the city itself, and specifically by the existence of garbage deposits or different kinds of waste products. The nature and characteristics or these waste deposits usually differ in every case, since they may correspond to urban solid waste with a great presence of organic matter, or inert spillings caused by industrial activities. The existence of these deposits is known with a higher or lower degree of accuracy in some cases, while it is absolutely unknown in others, because the old deposits were conditioned for a subsequent use of the ground in a way that after several years it would be impossible to identify their location just by observing the site.