From various points around this area and when you are flying in you get good views of Lake Kutubu. Here is some information on it.
Lake Kutubu is the second largest lake in the country. It is at an elevation of 808 meters with an area of 4,924 ha and was Until recently one of the most inaccessible areas in the country, with access only by light aircraft or on foot. The lake was formed when ash and debris from a volcanic eruption blocked of a valley. It has a maximum depth of approximately seventy meters. The lake depth can vary up to 2 m between the maximum height of a wet period and the end of a dry period. Annual average temperature is 23Â°C and rainfall is 4,500 mm.
The lake is fringed by reed-dominated swamp, especially at the northern and southern ends and The site includes seasonally inundated flatland swamp forest. During a scuba survey, several submerged cave systems were found.
Southern Highlands Province was the last area to be penetrated by the Australian colonial administration. The administration’s first outpost was established in 1939. Indigenous land use has changed little in the intervening 60 years, in this one of the most sparsely populated regions in the country. The Fasu people are spread widely to the west and southwest of the lake and own the land in which oil fields are located. Residents of the villages around the lake rely principally on the sago palm that provides 75% of their food volume (starch), as well as supplying building material. There is subsistence gardening, and hunting and fishing encampments. There have been several attempts to introduce cash crops, such as cocoa and coffee, but with little success thus far because of limited transportation. The development of oil and gas in the region has however, increased access through the development of road links and establishment of regular airplane flights.
(Most of this info comes from a website on wetlands preservation http://www.wetlands.org