''Blighted open area'', a predominantly open area which is detrimental to the safety, health, morals, welfare or sound growth of a community because it is unduly costly to develop it soundly through the ordinary operations of private enterprise by reason of the existence of ledge, rock, unsuitable soil, or other physical conditions, or by reason of the necessity for unduly expensive excavation, fill or grading, or by reason of the need for unduly expensive foundations, retaining walls or unduly expensive measures for waterproofing structures or for draining the area or for the prevention of the flooding thereof or for the protection of adjacent properties and the water table therein or for unduly expensive measures incident to building around or over rights-of-way through the area, or for otherwise making the area appropriate for sound development, or by reason of obsolete, inappropriate or otherwise faulty platting or subdivision, deterioration of site improvements or facilities, division of the area by rights-of-way, diversity of ownership of plots, or inadequacy of transportation facilities or other utilities, or by reason of tax and special assessment delinquencies, or because there has been a substantial change in business or economic conditions or practices, or an abandonment or cessation of a previous use or of work on improvements begun but not feasible to complete without the aids provided by this chapter, or by reason of any combination of the foregoing or other condition; or a predominantly open area which by reason of any condition or combination of conditions which are not being remedied by the ordinary operations of private enterprise is of such a character that in essence it is detrimental to the safety, health, morals, welfare or sound growth of the