This process has contributed to the growth of mega-urban regions (Jones and Douglass 2008) with their great demand for water and other natural resources. These changes have intensified the demand for water and many have also been highly polluting of water. All these developments affect water systems through diversion of water, bringing new uses of water, creating ecological changes and allowing for more rapid extraction of other natural resources such as timber. They can also displace very large numbers of inhabitants and, in some cases, settlements that have long histories as cultural heartlands.