Caspian Sea of around 149,200 square miles (386,400 square km)— bigger than the region of Japan—and its surface lies somewhere in the range of 90 feet (27 meters) below sea level. The sea bed in the southern part reaches as low as 1,023 m (3,356 ft) below sea level, which is the second lowest natural depression on earth after Lake Baikal (−1,180 m, −3,871 ft). The ancient inhabitants of its coast perceived the Caspian Sea as an ocean, probably because of its saltiness and large size. The sea has a surface area of 371,000 km (143,200 sq mi) (not including the detached
Water point mapping record all improved water points, being the water point basic sampling unit. This information can be then combined with data provided from a household survey to assess sanitation and hygienic habits. In terms of method, the approach adopted includes: (i) identification and audit of all improved water points; (ii) calculation of a sample size of households that is representative at and below the district level; and (iii) random household selection at the water point. WPM can be used to support different types of analysis, and specific applications include among others broad strategic planning, priority setting exercises and performance monitoring. Potential