Research on the swamps of Uganda

During the last few minutes of the air journey from London to Entebbe the observant newcomer is often mystified by what appear to be enormous grey-green rivers, some almost a mile wide, winding their way into Lake Victoria from an invisible distance in the west. These are the swamp valleys which drain some 150 miles of the gently sloping country between the wall of the Western Rift Valley and the lake. A swamp will form in any water which is sufficiently shallow and slow-moving to permit the establishment of a characteristic vegetation. This, nourished by material washed in from the surrounding land, will continue to form new growth while the older parts die and partially decompose to form a mass of waterlogged organic matter. The process is cumulative and a balance is ultimately reached between the production of organic matter and the flow of water tending to carry it away. In slow-flowing watercourses and stagnant basins the accumulation of organic matter and silt may raise the surface of the mud above the water level, thus permitting the .establishment of vegetation favouring drier conditions and finally of a covering plants resting on an accumulation of peat many feet in dept