The northern end of the Persian Gulf provides a sharp contrast to the arid-looking wetlands of northeast Kuwait (Bubiyan Island), the narrow corridor of Iraq, and the west-southwest marshes of Iran. The delta of the Tigris and Euphrates Rivers has suffered substantial environmental changes because of drainage, pollution, and urban and industrial development. Water normally supplied to the region has been diverted for irrigation and domestic and industrial consumption; wetlands have been drained for agriculture and industrial purposes; and the construction of dams has decreased the amount of fresh water from the Tigris and Euphrates Rivers, resulting in small quantities of silt being deposited in the delta of these once mighty rivers. The boundaries for Kuwait, Iraq, and Iran are not easily distinguishable in this photograph. The large dark area in Iran appears to be a freshwater marsh. Because natural materials are used for construction, the few towns and villages within the delta area tend to blend with the natural environment.