OVERLAND FLOW AND SURFACE RUNOFF / Hydrological Science and Engineering

Cape Verde, off the coast of Senegal in western Africa, is a volcanic archipelago where soil and water conservation techniques play an important role in the overall subsistence of half a million inhabitants. In fact, the step slopes in the more agricultural islands due to it's volcanic origin, together with semi-arid and arid environments (the country is located in the Sahelian region), characterized by a very irregular wet season, with high intensity rainfall events, make life tough. The hard conditions lead during the first half of the XX century to frequent cycles of drought with severe implications on the local populations, with impressive numbers of deaths by famine, and a decrease of the number of local inhabitants by more than halve in some islands. Maintain the soil in place and the water inside the soil was there after a mater of survival, and the CapeVerdians implemented over the last half century a number of soil and water conservation techniques that cover all the landscape. In this work, we monitored a number of slope soil and water conservation techniques, such as terraces, half moons, live barriers, etc, together with two cultural strategies, used to plant corn and beans on one side and peanuts on the other, with a semi-quantitative methodology, to evaluate their effectiveness. A discussion is given on the costs and effectiveness of the techniques to reduce overland flow production and therefore erosion, and to promote rainfall infiltration.

GUINEA-BISSAU: The Role of Local and International NGOs in Environmental Preservation and Sustainability of the Bijagos Archipelago

Bijagos Archipelago in Guinea-Bissau is at present subject to numerous external impacts that affect its centuries old balance. Since 1975 Guinean society has been using its natural resources in an uncontrolled way over the territory and especially in the coastal area. The archipelago has been increasingly raising interest, most of which is incompatible with the guarantee for a long-term sustainable development. It has also displayed a general impoverishment as far as resource preservation is concerned, due to internal demographic pressure of a population that has doubled since 1981 and to external pressure related to neighboring migrations and consequent depletion of non-renewable resources. This article aims to analyze the actions of local and international NGOs in the preservation and sustainability of the Bijagos Archipelago. We seek through an interdisciplinary approach to analyze the phenomena that are configured within the strategies of NGOs, on the assumption that these issues are articulated in the field of geography and sociology, as well as in politics and international cooperation. It is proposed new challenges to environmental issues, especially in a current situation shaken by constant instability internal and external policies.