MAPPING AND REMOTE SENSING OF THE RESOURCES OF THE REPUBLIC OF SENEGAL A STUDY OF THE GEOLOGY, HYDROLOGY, SOILS, VEGETATION AND LAND USE POTENTIAL SDSU-RSI-86-O 1 -Al DIRECTION DE __ Agency for International REMOTE SENSING INSTITUTE L'AMENAGEMENT Development DU TERRITOIRE ..i..... MAPPING AND REMOTE SENSING OF THE RESOURCES OF THE REPUBLIC OF SENEGAL A STUDY OF THE GEOLOGY, HYDROLOGY, SOILS, VEGETATION AND LAND USE POTENTIAL For THE REPUBLIC OF SENEGAL LE MINISTERE DE L'INTERIEUP SECRETARIAT D'ETAT A LA DECENTRALISATION Prepared by THE REMOTE SENSING INSTITUTE SOUTH DAKOTA STATE UNIVERSITY BROOKINGS, SOUTH DAKOTA 57007, USA Project Director - Victor I. Myers Chief of Party - Andrew S. Stancioff Authors Geology and Hydrology - Andrew Stancioff Soils/Land Capability - Marc Staljanssens Vegetation/Land Use - Gray Tappan Under Contract To THE UNITED STATED AGENCY FOR INTERNATIONAL DEVELOPMENT MAPPING AND REMOTE SENSING PROJECT CONTRACT N0 -AID/afr-685-0233-C-00-2013-00 Cover Photographs Top Left: A pasture among baobabs on the Bargny Plateau. Top Right: Rice fields and swamp priairesof Basse Casamance. Bottom Left: A portion of a Landsat image of Basse Casamance taken on February 21, 1973 (dry season). Bottom Right: A low altitude, oblique aerial photograph of a series of niayes northeast of Fas Boye. Altitude: 700 m; Date: April 27, 1984. PREFACE Science's only hope of escaping a Tower of Babel calamity is the preparationfrom time to time of works which sumarize and which popularize the endless series of disconnected technical contributions. Carl L. Hubbs 1935 This report contains the results of a 1982-1985 survey of the resources of Senegal for the National Plan for Land Use and Development. The more descriptive title, Mapping and Remote Sensing of the Natural Resources of Senegal, w3s adopted to describe this project, the final report of which fulfills the requirements of USAID contract AID/afr 685-0233-C-00-2013-00, applicable during the period of February 19, 1982 through May 31, 1985 and of USAID/Senegal contract, applicable June 1, 1985. The first contract required the delivery of materials and equipment, the collection of data and the training of Senegalese counterparts to project scientists. The second contract required the preparation and delivery of maps and reports describing the resources of Senegal. The delivery of materials and equipment took place during 1982 and 1983, and the collection of data by teams of both non-Senegalese and Senegalese experts began in 1982 and ended in 1985. Training activities also began in 1982 and terminated in 1985. The above subjects are treated in a previous report entitled Finl Management Report, SDSU-RSI-85-04. TIhe current report provides Senegalese governmental planning agencies and cooperating international agencies with the following products and supporting evidence. Resource Maps: Hydrogeologic map of Senegal showing geologic and hydrologic units as interpreted from Landsat imagery and field work. Scale 1:500,000. Four map sheets and a one-sheet legend with annotations. In color. Soils map of Senegal showing morphologic units as interpreted from Landsat imagery and field work. Scale 1:500,000. Four map sheets and a one-sheet legend with annotations. In color. Vegetation map of Senegal showing phytogeographic units. Scale 1:500,000. Four map sheets and a one-sheet legend with annotations. In color. i Th'amatic Maps: Land use map of Senegal showing present use of land in terms of major crops, forestry and/or rangeland. Scale 1:500,000. Four map sheets and a one-sheet legend with annotations. Black and whits. Groundwater table and well location map of Senegal showing depth to groundwater and wells measured by the Project. Scale 1:500,000. Four map sheets and a legend with annotations. Black and white. Synthesis Maps (cartes de synth~se): Land/soil capability map of Senegal showing potential for agriculture, forestry and grazing. This map indicates three to five levels of suitability. Scale 1:500,000. Four map sheets with a legend and annotations. Black and white with patterns. Tectonic map of Senegal showing major structural units and their relationship to mineral and groundwater potential. Scale 1:1,000,000. One map sheet with a legend and annotations. Black and white. Soil degradation map of Senegal showing areas of wind and water erosion, saline incursion and areas under ecologic pressure due to human degradation. Scale 1:1,000,000. One map -.heet with legend and annotations. Black and white. Vegetation degradation map of Senegal showing pressure on phytogeographic units due to lack of water and/or soils degradation, etc. Scale 1:1,000,000. One map sheet with legend and annotations. Black and white. Water and mineral map of Senegal showing areas of high probability for water at indicated depths and the country's mineral potential. Scale 1:1,000,000. One map sheet with legend and annotations. Black and white. ii ACKNOWLEDGEMENTS After four years of work it is very difficult to know where to begin to thank those responsible for the success of this effort. We are deeply indebted to many in Senegal, the United States and other parts of the world. We sincerely hope that our debt will be in part repaid by the utility of our work. Special recognition is given to the Senegalese government for its interest in the project. The support of his excellency the Minister of the Secretariat of Decentralization, Moussa Ndoye, and his staff was particularly gratifying. Our thanks also goes to the members of the Bureau d'Organization et Methode at the Presidency of the Republic for their concern and interest. We would like to thank the director and staff of the Direction de l'Am6nagement du Territoire for their interest and criticism. We are also most grateful to all the government agencies' workers who assisted, giving of their time and in many cases, their friendship. We should be remiss if we did not individually name those members of the various agencies who strove with us to improve our knowledge of Senegal. Our special thanks go to Alioun Badian, DAT; Luc Dubois, PNUD; A.K. Fahem, PNUD; Dr. P. Michel, Strasbourg; A. ENEA; Hadj, B. Dieng, J. Le Priol and P. Curretti, Directicn d'Etudes Hydrauliques. Very heartfelt thanks are due to the Geography Department of the University of Dakar and all its members for the patience, understanding help and friendship shown to the project. Our thanks are due particularly to Dr. Diop, who helped us catalog our samples and the Direction des Mines et Gdologie where help and friendship were gencrously proffered by Mr. Cheirrk Faye and the of the library. staff The assistance of IFAN and ORSTOM were also much appreciated. At USAID we are especially grateful to Mrs. Littlefield, the Director, and her predecessor, Mr. Shear; the project officer, Mr. Harvey, and his predecessor, Mr. Larry1 Harms; and particularly to David Diop and Ang4lique who kept the project going with their good humor, hard work and patience. Of course we are also indebted to many other AID employees, Senegalese and Aw.drican, for their assistance and support, particularly consulting ecologist Dr. Gene Eulert for his valuable insight into field methods and mapping. Upon our return to RSI, the arduous task of completing maps and reports fell upon a most cooperative staff. We thank Lisa, Melanie, Rick, Barb, Lillian, Jan, Bob, Russ, Rahim, Hamid, Joanne, Paul, Janet, Mary and Kevin for their hard work. Special thanks are extended to Doug "Waldo" Van Driel for drafting the figures, Bob Markowitz for his pen and ink interpretations of the Senegalese landscape, Sheryl Bolton for typing the manuscript, Shirley Lyons for typesetting, Tom Coblentz for map preparation, Anne Gellner for a gifted translation and Jeanne Lesinski for patience in editing the manuscript. iii Our work could never have been accomplished without our project staff in Dakar. We would like to recognize its members for their hard work and cooperation during some difficult and some very good times; we hope that the memories they have will be as good as those we cherish of our time together. We thank: M. Cisse - guard M. Coli - guard M. Diaga - guard A. Diallo - guard S. Diallo - chauffeur M. Darboe - guard S. Darboe - chauffeur M. Da Silva - chauffeur I. Diop - draftsman M. Gadiaga - draftsman L. Hulten - administrative assistant D. Ka - administrative assistant C. Lamotte - accountant A. Ouattara - secretary M. Ndiaye - cleaning personnel I. Thior - gardener All our work would have been for naught had it not been for the assistance we received from innumerable people in the Senegalese countryside. We are most thankful to those who pushed our cars when we were stuck, those who generously fed us and those who received us in their homes when we were tired, dirty and in need of moral support, which they gave so thoughtfully. We thank in this regard our friends in Thiel, Lingu-re, Bakel, Koumpentoum and at the "Hotel Diouf" in Tambacounda. Finally, we would like to acknowledge our debt of gratitude to those who will carry on in remote sensing in Senegal and with whom we shared much more than professional concerns. These individuals gave much to the project's success. They worked hard and sacrificed much so that the results would make life better for their compatriots. They gave to their country and to us. For this we thank the following friends and scientists: A.K. Cisse - Homologue au chef du projet, DAT A. Bodian - Botaniste, Dir. des Eaux et Fordts A. Sow - Gdologue, Dir. des Mines et Geologie K. Diatta - Gdographe, DAT B. Diouf - Gdographe, Prof. A. Niang - Am~nagiste, DAT iv We would like to dedicate this work to two men who have long worked to bring remote sensing to its rightful place in the scheme of global resource development, monitoring and planning.