7a UNESCO-IHE Institute for Water Education Comparative assessment of the vulnerability and resilience of deltas Extended version with 14 deltas work document Lead authors Tom Bucx (Deltares) Wim van Driel (Alterra-Wageningen UR) Hans de Boer (TU-Delft) Susan Graas (UNESCO-IHE) Victor Langenberg (Deltares) Marcel Marchand (Deltares) Cees van de Guchte (Deltares) Main authors of delta descriptions Ayeyarwady Wim van Driel, Alterra Wageningen UR, Nile Shaden Abdel-Gawad, National Water Research The Netherlands Center, Egypt Tjitte Nauta, Deltares, The Netherlands Incomati Antonio Hoguane, Eduardo Mondlane University, Arantza Pi Gonzalez Alterra Wageningen UR, Mozambique The Netherlands Frank van der Meulen, Deltares, the Netherlands Zaw Lwin Tun, Hla Oo New, Phyo Myint, Irrigation Department, Myanmar Ganges- Emaduddin Ahmad, Asif Mohammed Zaman, Zahir Brahmaputra- Haque Khan, S.M. Mahbubur Rahman, Institute of Parana Zagare, Verónica M.E., Delft University of Meghna Water Modelling, Bangladesh Technology / University of Buenos Aires Blanco, Daniel E., Machain, Natalia, Fundación Yangtze Wenwei Ren, Yi Yong, Xinghua Fu, World Wide Humedales / Wetlands International Fund for Nature, China Carlino, Hernán, Instituto Torcuato Di Tella Ciliwung Jan Sopaheluwakan, Heru Santoso, Indonesian Quintana, Rubén, Universidad Nacional de Institute of Sciences, Indonesia San Martín / Fundación Humedales / Wetlands International Mekong Le Quang Minh, Vietnam National University Ho Chi Kandus, Patricia, Universidad Nacional de San Minh City, Vietnam Martín Ceballos, Darío, INTA (Instituto Nacional de Rhine Meuse Bart Makaske, Alterra-Wageningen UR, the Netherlands Tecnología Agropecuaria) Arjan Berkhuysen, World Wide Fund for Nature, the Netherlands Tana Prof E. Odada, United Nations University Regional Centre for Water Education Kenya, Danube Adrian Stanica, Nicolae Panin, National Institute for Dr. Victor Langenberg, Deltares Research and Development of Marine Geology and P. Odhengo, Ministry of Finances, Kenya Geoecology, Romania California Peter Wijsman, Arcadis, USA Zambezi Omar Khan, MSc, Eduardo Mondlane University, Bay-Delta Faculty of Engineering, Maputo, Mozambique. Dinis Juizo, PhD, Eduardo Mondlane University, Mississippi Anthony Fontenot, Princeton University, USA Maputo, Mozambique. Richard Campanella, Tulane University, USA Susan Graas, UNESCO-IHE Institute for Water Education, Delft, The Netherlands In addition the World Wide Fund for Nature contributed to the delta descriptions of the Ganges-Brahmaputra-Meghna, Ciliwung and Mekong. The assessment of the Ayeyarwady Delta has been made possible with the support of the Global Water Partnership and the Bay of Bengal Large Marine Ecosystem (BOBLME) project coordinated by FAO. Internet For more information about the Delta Alliance and to download this Work document and other related documents go to www.delta-alliance.org Citation Bucx, T., W. van Driel, H. de Boer, S. Graas, V.T. Langenberg, M. Marchand and C. Van de Guchte. 2014: Comparative assessment of the vulnerability and resilience of deltas – extended version with 14 deltas - synthesis report. Delta Alliance report number 7. Delta Alliance International, Delft-Wageningen, The Netherlands This research project was carried out in the framework of the Dutch National Research Programme Knowledge for Climate (www.knowledgeforclimate.org). This research programme is co-financed by the Ministry of Infrastructure and Environment (I&M). The authors are fully responsible for the choice and the presentation of the facts contained in this research and for the opinions expressed therein. However, despite the best intentions, errors, incomplete source references Design and lay-out or misinterpretations might have crept in for which we sincerely apologize. Deltares Any use of the content of this publication is for the own responsibility of the user. The Foundation Knowledge for Climate (Stichting Kennis voor Klimaat), its organisation members, the authors of this publication and their August 2014 organisations may not be held liable for any damages resulting from the use of this publication. Comparative assessment of the vulnerability and resilience of deltas Extended version with 14 deltas work document Table of Contents 11 Tana delta 5 12 Zambezi delta 33 13 Ayeyarwady delta 66 14 Parana delta 107 Continent Country Delta No Egypt Nile 1 Kenya Tana 11 Africa Mozambique Incomati 2 Mozambique Zambezi 12 Bangladesh Ganges-Brahmaputra-Meghna 3 China Yangtze 4 Asia Indonesia Ciliwung 5 Myanmar Ayeyarwady 13 Vietnam Mekong 6 The Netherlands Rhine-Meuse 7 Europe Romania Danube 8 United States of America California Bay-Delta 9 N-America United States of America Mississippi River Delta 10 Z-America Argentina Parana 14 Overview of all 14 deltas with in green the four additional deltas elaborated in this work document. See www.delta-alliance.org for the work document with the descriptions of the other 10 deltas. Tana delta No 7 8 9 4 10 1 11 3 13 6 11 111 5 12 2 14 Tulu Moa KENYA Tana Delta Kipini North Kenya Bank Indian Ocean 0 50 km Tana delta 1. Current and future state of the Tana Delta N.B. This description refers only to the lower Delta region of the Tana River basin (in general 0–40 m above sea level, reaching to 50 km inland). 1.1 Drivers of change Summary of drivers of change Demographic trends: The Tana Delta has ca. 100,000 residents. With the total number of households of 12,457, and a mean household size of ca. 7 persons, the Delta population is growing at an estimated 3,62% a year. Over the past decade, conflicts have been increasing in the Tana River Delta as a result of increasing population, the majority of whom (over 90%) live in the rural areas Economic developments: The main economic activities are farming, livestock keeping (pastoralism) and fishing. The settlement patterns are random but are concentrated close to the river. The Tana Delta a dry season grazing area for livestock emanating from other Counties. Fuel wood is derived from forests and woodlands located in the delta. Other products include medicinal herbs, honey and eco-tourism, including several lodges and a wildlife conservancy. Strong developments are expected in the delta due to the implementation of the Lamu Port Southern Sudan-Ethiopia Transport (LAPSSET) Corridor (see 1.1.4 for more information). Climate change: Wide fluctuations in climatic conditions including pronounced flooding and droughts are experienced. In the next 20 years rainfall may be more prolonged, bimodal erratic, unreliable, and consequently cause more flooding events (although these may be counteracted by the building of the High Grand Falls Dam, see). In the next 40 years a possible increase of 15-25 cm in mean sea level could significantly reduce the scope of farming on those parts of the lower floodplain lying within 20 to 30 km of the coast. Subsidence: Unknown due to lack of data. However, human induced subsidence is likely to occur when downstream sediment supply decreases due to upstream dams and reservoirs, promoting the net change in sea level rise at the coast. Subsidence due to tectonic activity or by compacting organic layers is assumed to be small. Technological developments: The technological developemnts in the delta are currently limited in comparison to dams and reservoirs for power and irrigation upstream. However, the planned LAPSSET foresees major development push in infrastructure, large scale agriculture, logistics, and energy and water production. Research gaps Research is required in the development of impact assessment tools for various climatic impacts on delta health and functioning. The complete impact of climate change and the planned developments on delta morphology is unknown. 1.1.1 Socio-economics (population growth- migration, economic development + most relevant sectoral developments, e.g. for agriculture, fisheries, industry) Population and demography Tana River Delta is an area with a modest population. The area is characterized by a migratory Comparative assessment of the vulnerability and resilience of deltas - Extended version with 14 deltas | Work document 6 Tana delta population consisting of livestock herders who migrate to the lower plains during the drought months. In comparison with the whole Tana district with more than 240,000 people, the population of Tana River Delta district is estimated at ca. 100,000 based on the 2009 census using a growth rate of 3.62% (KNBS, 2009; Government of Kenya, 2010). The total number of households in the delta is 12,457 with mean household size of ca. 7. The population density in the district ranges from 4 – 27 persons per km2 with a mean of 7. The main economic activities are farming, livestock keeping (pastoralism) and fishing.Agriculture employs about 60% of the population while 40% work in the livestock sector that in comparison to agriculture requires expansive landscape. The communities living in the delta are: Pokomos - 44%, Ormas - 44%, Wardei - 8% while the other ethnic groups, including Luo account for the remaining 4%. The Wardei are a smaller pastoralist group originating from Ethiopia. The Pokomo are mainly subsistence farmers who farm along River Tana. The district suffers under heavy burden of high incidence of poverty estimated at 76% compared with a national average of about 50%. The unemployment rate in the district is estimated at 33% compared with a national average of 20%. Over the past decade, conflicts have been increasing in the Tana River Delta as a result of increasing population, the