Multi-dimensional nature of drought in Abbay/Upper Blue Nile Basin and the importance of regional coordination efforts for mitigation DEVELOPING AN IMPACT-BASED COMBINED DROUGHT INDEX FOR MONITORING CROP YIELD ANOMALIES IN THE UPPER BLUE NILE BASIN, International Conference on the Nile and Grand Ethiopian Renaissance ETHIOPIA Dam: Science, Conflict Resolution and Cooperation August 20-21, 2020 By: Yared A. Bayissa, Semu A. Moges, Assefa M. Melesse, Tsegaye Tadesse, Anteneh Z. Abiy 08/20/2020
Outline Background Drought history of the UBN basin Material and methods Spatial and temporal features of different types of droughts Drought impact on socio-economic Summary and recommendation 9/10/20
Background Historic droughts in Ethiopia 1983/84 was one of the worst drought events Covered large area and affected many populations Drought has become more frequent (Data source: EM-DAT: The International Disaster Database. Centre for Research on the Epidemiology of Disasters-CRED) Now it occurs every 2 to 3 years Drought impacts on Ethiopia economy The economy is less resilient to drought The economy is highly linked to annual rainfall variability (Source: Economics of resilience to drought: Ethiopia analysis (USAID report, 2018)) 9/10/20
Cont’d … Natural Climate Variability Precipitation deficiency Hydrological Agricultural Meteorological High temp, high winds, low (amount, intensity, timing) relative humidity drought drought drought (amount, intensity, timing) D Reduced infiltration, runoff, Increased evaporation and u deep percolation, and GW transpiration r Soil Water Deficiency a t Plant water stress, reduced i biomass and yield o Reduced streamflow, inflow to reservoirs, n lakes, and ponds; reduced wetlands, wildlife habitat Economic impact Social Impact Environmental impact Proceeding of precipitation deficit throughout the Influence of precipitation deficiency and other factors on drought development Hydrological cycle (Rasmusson, 1993) (National Drought Mitigation Center) 9/10/20
Cont’d … Demonstrate the different forms of droughts that occurred in the Abbay/ Upper Blue Nile River basin and its national and regional implication 9/10/20
Drought history of the UBN basin - UBN basin is vulnerable to drought - 1984, 2002, 2009 and 2015 drought years - The eastern part more drought susceptible - Regional cooperation is vital to mitigating its impact 9/10/20 6
Material and methods Drought indices Standardized Precipitation Index Soil Moisture Deficit Index Surface Runoff Index 9/10/20
Land Data Assimilation System Cont’d … Long-term (FLDAS) Stream flow (Monthly soil moisture time series) Standardized Runoff Index (SRI) Soil Moisture Deficit Index (SMDI) Soil Moisture Deficit Index (SMDI) - Seasonal Surface Runoff - Annual time scales Index (SRI) - Seasonal !' #,% − )!' % !" #,% = ×100, +0 !' #,% < )!' % )!' % − *+, ! ' - Annual % !' #,% − )!' % !" #,% = ×100, +0 !' #,% > )!' % *23 ! ' % − )!' % %89 + !" Hydrological drought assessment % !)"5 #,% = 0.5!)"5 100 Agricultural drought assessment Generating maps Drought category Index value Near Normal 0.50 - -0.49 Mild drought -0.50 - -0.99 Moderate drought -1.00 - -1.49 Severe drought -1.50 - -1.99 Extreme drought < -2.00 9/10/20
Spatial features of meteorological and agricultural droughts Seasonal SPI (JJAS) Seasonal stdSMDI (JJAS) ´ Extreme drought Severe drought Moderate drought Mild drought Near Normal Unusual Moist Moderate Moist Very Moist Extremely Moist UBN Basin Lakes Main River - Similar drought pattern b/n SPI and stdSMDI in 1984 and 2015 - Wide spread and severe drought is shown by stdSMDI as compared to SPI in 2002 and 2009 9/10/20
Cont’d … Annual SPI Annual stdSMDI 1984 2002 ´ Extreme drought Severe drought Moderate drought Mild drought Near Normal 2009 2015 Unusual Moist Moderate Moist Very Moist Extremely Moist UBN Basin Lakes Main River - Similar drought patterns as compared to seasonal for the selected years - Relatively widespread and intensified drought condition in 1984, 2002 and 2009 9/10/20
Temporal pattern of meteorological, agricultural and hydrological droughts Seasonal Annual 3 3 2 2 1 1 Index values [-] Index values [-] 0 0 -1 -1 -2 -2 stdSMDI SRI SPI stdSMDI SRI SPI -3 -3 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 Seasonal correlation coefficient Annual correlation coefficient SPI SRI SPI SRI SRI 0.79 SRI 0.85 stdSMDI 0.56 0.64 stdSMDI 0.67 0.49 - There is a high nexus between each drought type and all indices consistently indicated the historic drought events in the basin. 9/10/20
Drought impact on socio-economic Number of population in need for relief food assisstance (1982-2000) 12 11 10 9 8 Needy People [10^6] 7 6 5 4 3 2 1 0 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 (Source: Abate, 2003) Year 9/10/20
Summary and recommendation We recommend constructing upstream storage The nature of drought in Abbay/UBN facilities to delink drought induced socio-economic basin is multi-dimensional and occurring losses and to mitigate the multi-dimensional concurrently drought related disaster It has both complementary as well as Understanding multidimensional aspects of drought supplementary socio-economic impacts provides perspectives for regional cooperation and (agriculture, GDP) the need for shared drought management 9/10/20
Multi-dimensional nature of drought in Abbay/Upper Blue Nile Basin and the importance of regional coordination efforts for mitigation DEVELOPING AN IMPACT-BASED COMBINED DROUGHT INDEX FOR MONITORING CROP YIELD ANOMALIES IN THE UPPER BLUE NILE BASIN, International Conference on the Nile and Grand Ethiopian Renaissance ETHIOPIA Dam: Science, Conflict Resolution and Cooperation 08/20/2020
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