PROGRAM TITLE: Nile Delta Subsidence and Sea Level Rise ACTIVITY STREAM: Process Studies SCIENCE ELEMENT:Solid Earth Processes , Earth System History SMITHSONIAN INSTITUTION NATIONAL MUSEUM OF NATURAL HISTORY (NMNH) SCIENTIFIC MERIT: The Nile Delta Project, a multi-disciplinary and international program, was initiated at the Smithsonian's National Museum of Natural History in l985 to measure recent, and predict future, changes in Nile Delta coastal plain subsidence, sea level rise, coastal retreat, wetland loss, saline ground water intrusion and impact on Egypt's population of 55 million. The program also to identifies paleoclimatic changes and their effects on the Nile drainage system in East and Central Africa, and desertification effects on the Nile Delta. Major ecological changes are modifying the delta, due in part to (l) man (Aswan High Dam, intensified irrigation, drainage of lagoons, etc.) and to natural factors that are (2) inducing salt water incursion and coastal and wetland losses (sea level rise due in part to land subsidence) and (3) desertification (recording part climate changes in Northeastern Africa, Sahel). By focusing on the sediment record in the Nile Delta we are now formulating a means to recognize how sea level and climates have changed during the past l0,000 years. Predicting future changes cannot be done unless we comprehend both natural and human factors that have modified this region in the recent past. The investigation in the northern Nile Delta is coupled with data collected offshore in the Mediterranean on the Nile Cone (studies at Smithsonian to the early l980's). Present studies plan field work in the central and southern Nile Delta and Upper Egypt and, subsequently, in Sudan and Ethiopia, to identify changes in climate and sources of sediment fed by the Nile to the Mediterranean coast. In addition to drilling, on-going studies include sedimentary petrology, organic and inorganic geochemistry, radiocarbon- dating, faunal and floral studies, satellite imagery/remote sensing, and high- resolution subsurface seismic profiling. The data-base provides increasingly precise correlations to measure changes of land subsidence, sea level rise (and coastal and wetland losses) and desertification with time, and to allow reasonable predictions. Field study during 5 field seasons of the entire northern Nile Delta coast and delta plain was initiated in l985 (includes collection of about l00 long sediment borings, to 60 m, and surficial sediments). The major result to date is recognition of rates of subsidence locally to 0.5 cm per year, and a projected minimal incursion of the sea to 30 km inland by the year 2100 in the northeastern Delta. Coring, mapping and laboratory analyses of surface and subsurface samples will provide rates of subsidence across the delta plain, from east to west of Alexandria. The program involves the efforts of several disciplines: geology (primarily sedimentology, paleontology, geochemistry), remote sensing, physical geography, archaeology, zoology and botany. The study is being undertaken and coordinated with scientists in Egypt and other foreign organizations. All data, entered and archived (software storage) is being analyzed at the Smithsonian's NMNH and in 12 other laboratories in North America, Egypt, and Europe. STAKEHOLDERS: The project at the Smithsonian is a multi-disciplinary effort in collaboration with 12 other laboratories in North America, Egypt and Europe, and interacts with complementary projects sponsored in the Mediterranean basin (UNESCO, World Bank and others). Data sets are made available to collaborators within the Smithsonian and in laboratories and organizations associated with the Mediterranean Basin Program. Inundation and massive salt incursion are directly affecting the lives of the 55 million Egyptians tightly concentrated in only 4% of their country's area. Both man's influence (Aswan High Dam) coupled with natural effects (land subsidence and sea level rise) are having catastrophic impacts on this, one of the politically stable regions in the Middle East. The Nile Delta Project is identifying those sectors of the Delta that can still reasonably be protected by man as these changes occur. POLICY RELEVANCE: Until initiation of this program in l985, virtually no direct refined measurements had been made of land subsidence and sea level rise rates in the northeastern African sector. Crustal subsidence and climatic changes both affect sea level in this low-lying region that is of less than l m elevation. Additional problems of ground water salinization affecting agriculture and changes in lagoons vital to fishing affect the well-being of Egypt's growing millions. Of particular urgency are changes being induced by the closure of the Aswan High Dam. The effects of climatic changes during the recent past are now being correlated with archaeological sites and earlier geographic studies; desertification in the Delta is also related to changes in the Sahel. The investigation meets several top priority objectives of the U.S. Global Change Research Program. Measurements of subsidence of the low-lying Nile Delta plain bear directly on predicting rising sea level and its effects on one of the world's highest concentrated populations. Rapid salt water incursion, lagoon modification, coastal erosion and wetland loss together constitute a very high priority issue specifically relating to Solid Earth Processes (primary) and climatic change in Earth System History (secondary) elements. In addition to loss of wetlands (there are 4 major lagoons along the delta margin) and very rapid coastal retreat (locally to l00 meters per year or more) in conjunction with sea level rise, there are problems of desertification in conjunction with climate change in the northeastern African sector. PROGRAM CONTACTS:SI SGCR Representative: Ted A. Maxwell NASM MRC 315 Smithsonian Institution Washington, D.C. 20560 202 357 1424 FAX: 202 786 2566 Email: tmaxwell@ceps.nasm.edu Bureau Representative: Marsha Sitnik NMNH MRC 106 Smithsonian Institution Washington, D.C. 20560 202 357 2670 FAX: 202 786 2934 Email: nmhod004@sivm.si.edu