The Open Space District is intended to provide permanent open space for its natural beauty and recreational value. It is also intended to preserve natural resources, to prevent erosion, pollution and siltation and to safeguard the health, safety and welfare of persons and property by limiting development on excessive slopes, on floodplains, or poorly drained lands or on other areas where protection against natural dangers to life and property, or the lack of such protection, would prove costly to members of the community.