Definition   All soils have basic physical, chemical, and biological properties that influences development practices and biological processes. The basic functions of soil are to regulate water flow, store nutrients and water, act as a medium for plant growth, and provide an environmental filter. Important health indicators include those related to water storage and movement, soil structure, soil stability, presence of nutrients, presence of toxic metals and chemicals, availability of oxygen and gas exchange, diversity of organisms, presence of organic matter. Many of these indicators are interrelated, such as the effect of soil structure on water relating properties, and the availability of nutrients with the presence of soil biota. The best soil health indicators are those that integrate the combined effects of several properties and processes.             Urban soils are disturbed and changed by the process involved in the development of the urban infrastructure and impose serious constraints on root systems, storm water infiltration and organisms. Why? Natural profiles are rarely present in urban soils. "In geologic terms, urban soils are recent formations, and human activity has been the dominant geomorphic agent in the development of these soils." (Smith 1998) Restrictions in drainage and aeration of urban soils can be caused by these abrupt textural and structural changes within the profile depth.