Soil erosion in the Kingdom of Lesotho and the development of Historical Environmental Impact Assessment

Solutions to past environmental problems affect the landscape. Their evaluation is often limited by a lack of scientific data. Yet valid scientific questions remain for which alternative research methods must be found. Soil erosion and the effects of conservation methods in the Kingdom of Lesotho, southern Africa, posed such problems. Three separate but complementary studies used field observations, archival research, and interviews with rural people to obtain information about past conditions of the landscape and the effects of soil conservation programs. At the time of the first conservation program in the 1930s, soil erosion was not widespread. The primary cause of gully erosion was roads and paths. A structure-based conservation program to protect the landscape actually caused gully initiation in some fields. While official documents provided general descriptions, older people gave detailed descriptions of erosion processes. They also described their own monitoring of the structures and efforts to mitigate their ill effects. The removal or modification of structures was an act of conservation, not of destruction. These studies led to the formulation of an historical environmental impact assessment (HEIA) to reconstruct the effects of past interventions in landscapes. The steps of conventional impact assessments were modified for work in the past, HEIAs could provide information about undocumented environments, extend baselines of modern EIAs, and identify past failures and successes to guide modern programs.