Mainstreaming Climate Change for Sustainable Development of Sri Lanka 19-21 August 29 Adaptation to Climate Change Irrigation Sector in Sri Lanka Eng. H. M. Jayatillake Director (Irrigation & Water Management) Irrigation Department Bauddhaloka Mawatha, Colombo 7. Email: <ddim@eureka.lk> Water/ Irrigation Manager/ Engineers Role Deals with floods, Droughts, Extreme events in there normal work Some adaptations take place for effects and impacts of climate change & variability 1
Where do we have to adapt? Drivers Change Effect Impact Mitigation? Adaptation Tools for Diagnosis 2
Performance monitoring of irrigation systems All Island Average Croping Intensity of Major Schemes & Yala Extents - 1993/94 to 23/4 Cropping Intensity 1.8 1.6 1.4 1.2 1..8.6.4.2. 1.5 1.45 1.36 1.26 1.6 1.62 1.68 1.57 1.55 1.56 1.39 93 /94 94 /95 95 /96 96 /97 97 /98 98/99 99/ 2/1 2/2 2/3 2/4 Cropping CROPPING INTENSITY 5 45 4 35 3 25 2 15 1 5 Extent Yala (Acs) EXTENT YALA Benchmarking of irrigation system performance AV. ANNUAL CROPPING INTENSITY 93/94,97/98 - Inter Prov Schemes over 4 ha 2.5 2. 1.5 Anticipated Design CI 1.5 1..5. 3
Studies 1 ADAPT Study on Adaptation to Changing Environments. Water, Climate, Food, and Nature Some Trends in Walawe Basin (Pilot) Catchment Area Annual Rainfall Runoff Escape to Sea 2471 Sqkm 186 mm 2221 MCM 525 MCM Walawe Basin 4
Climate Change Trends Mean Annual Temperature Hambantota (Lower Walawe Basin) 187-21 3. Mean Annual Temperature - Hambantota Degrees Celcius 29. 28. 27. 26. 25. 187 1876 1882 1888 1896 192 198 1914 192 1926 1932 1938 1954 196 1966 1972 1978 1984 199 1996 Annual Av Linear (Annual Av) Clear Increasing Trend with Prominence After early 197s CC Trends Mean Annual Temperature Ratnapura (Upper Walawe Basin) 196-2 3. Annual Mean Temperature o C - Ratnapura Degrees celcius 29. 28. 27. 26. 25. 196 1911 1916 1921 1926 1931 1936 1941 1946 1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 Annual Mean Linear (Annual Mean) Similar increasing Trend 5
Annual Rainfall Trends from 191 to 2 mm Annual Rainfall Trend from 191 to 2 - Walaw e in Holmw ood: Lat: 6.85 o N Lon: 8.72 o E El: 1685. m 45 4 35 3 25 2 15 1 5 191 195 199 1913 1917 1921 1925 1929 1933 1937 1941 1945 1949 1953 1957 1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 Holmw ood Filtered Poly. (Holmw ood) Walawe in Holmwood A Reducing Trend from early 7s Annual Rainfall Trends from 191 to 2 - Annual Rainfall Trend from 191 to 2 - Walaw e in Sandringham: Lat: 6.85 o N Lon: 8.75 o E El: ****** m 4 35 3 25 mm 2 15 1 5 191 195 199 1913 1917 1921 1925 1929 1933 1937 1941 1945 1949 1953 1957 1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 Sandringham Filtered Linear (Sandringham) Walawe in Sandrignam A High Variability 6
Annual Rainfall Trends from 191 to 2 - mm Annual Rainfall Trend from 191 to 2 - Walaw e in Annifield: Lat: 6.87 o N Lon: 8.63 o 45 4 35 3 25 2 15 1 5 Annifield Filtered Linear (Annifield) EL: 1311. m Walawe in Annfield An Increased Variability Annual Rainfall Trends from 191 to 2 35 Annual Rainfall Trend from 191 to 2 - Kirindi Oya in Dyraba - Lat: 6.88 o N LON: 8.93 o E EL: 1299. 5 M 3 25 mm 2 15 1 5 1915 1919 1923 1927 1931 1935 1939 1943 1947 1951 1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 Dyraba Poly. (Dyraba) 5 per. Mov. Avg. (Dyraba) Dyraba in Kirindi Oya- Adjacent Basin A reducing Trend with high variability after 197s 7
Climate Change Rainfall - Seasonal Trends Hambantota Oct March Maha Season High Variability Rainfall in mm 1 9 8 7 6 5 4 Seasonal Rainfall Hambantota Met Maha Season (October to March) - Period 1971-21 Lat: 6.12N Log: 81.13E Ele: 15.5m 3 2 8 7 6 5 4 3 2 1 1971 1972 1973 1974 1975 1976 1977 1978 1979 198 1981 1982 1983 1984 1985 1986 1987 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 1999 2 21 1971/72 1972/73 1973/74 1974/75 1975/76 1976/77 1977/78 1978/79 1979/8 198/81 1981/82 1982/83 1983/84 1984/85 1985/86 1986/87 1987/88 1988/89 1989/9 199/91 1991/92 1992/93 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 1999/ 2/1 April- Sept Yala Season A Reducing trend?? Rainfall in mm Seasonal Rainfall Hambantota Met - Lat: 6.12N Log: 81.13E Ele: 15.5m Yala Season (April to September) - Period 1971-21 Walawe River Flows 1942-67 before Uda- Walawe Reservoir A reducing trend has been there and can be due to many reasons 16 Seasonal River Runoff Walawe at Embilipitiya 12 MCM 8 4 42/43 46/47 5/51 54/55 58/59 62/63 66/67 Maha Yala 8
Warming Trend 195-2 s where Average Temperature is 1oC above Average- Hambatota (Jayatillake & Droogers, 22) Warming - Forecasts Successive Warm s 1oC above normal Walawe (Jayatillake & Droogers, 22) 9
Drought Forecasts Successive Dry s (Jayatillake & Droogers, 22) Precipitation Forecasts Walawe Basin 3 Precipitation (mm y -1 ) 25 2 15 1 5 HADCM3_A2 HADCM3_B2 ECHAM4_A2 ECHAM4_B2 1961-21- 27-1961- 21-27- 1961-21- 27-1961- 21-27- 199 239 299 199 239 299 199 239 299 199 239 299 Models show an increased Precipitation & generally high variability 1
Study 2 UN- World Water Assessment Programme Sri Lanka Case Study Sri Lanka s Temperature is rising at a rate much higher than the Global Average Rise.6oC Global Vs 1.6oC in Sri Lanka for 1 s. 11
Annual Rainfall Deviation from Mean A Reduction of around 7% in annual rainfall after 197s The Change has not been uniform over different Rainfall Seasons 7 Average Rainfall during Different Rainfall Seasons in periods 1931-6 & 1961-9 6 5 Rainfall mm 4 3 2 1 First Inter MonsoonSouth-West Monsoon (Mar-Apr) (May-Sep) Second Inter- Monsoon (Oct-Nov) North-East Monsoon (Dec-Feb) 12
Highest Change in North-East Monsoon followed by FIM %Change of Seasonal Rainfall from 1931-6 to 1961-9 1% 5% % Change % -5% -1% -15% -2% -25% First Inter Monsoon (Mar-Apr) South-West Monsoon (May- Sep) Second Inter- North-East Monsoon (Oct-Nov) Monsoon (Dec-Feb) Highest Variability too in NEM followed by FIM Stabilized SWM Coefficient of Variation 45% 4% 35% 3% 25% 2% 15% 1% 5% % Coefficient of Variation of Seasonal Rainfall - Periods 1931-6 & 1961-9 First Inter Monsoon (Mar-Apr) South-West Monsoon (May-Sep) 1931-6 1961-9 Second Inter- North-East Monsoon Monsoon (Oct-Nov) (Dec-Feb) 13
Watersheds and the highest paddy producing areas are the worst affected Change in Rainfall mm 1.. -1. -2. -3. -4. -5. District wise Change in Annual Mean Rainfall from 1931-6 to1961-9 mm Colombo Matara Vavuniya Hambantota Kalutara Puttalam Galle Gampaha Mannar Ratnapura Trincomalee Jaffna Kilinochchi Anuradhapura Polonnaruwa Batticaloa Kurunegala Monaragala Mullaitivu Kegalle Nuwara Eliya Badulla Ampara Kandy Matale ud;f,a Examples Kirindi Oya Kirindi Oya - s of low cropping Weheragala Diversion to KO is to be commissioned this week 14
Some Adaptation Measures implemented Reduction in Land Preparation Period to 3-4 wks Adoption of Short Maturing Varieties Work From Approx: 4-4 ½ months varieties to 3 ½ Months varieties) Overall water issue period could be reduced to 4 months from 5 ½ months over time Water Issue Periods Maha Four Polonnaruwa Systems Days Fig.8a: Polonnaruwa Water Issue Periods Maha Seasons From 1994/95 - Intervention 152 152 158 P.S.S 15 141 147 156 145 149 Giritale 131 125 126 151 162 154 Minneriya 133 136 135 151 146 Kaudulla 121 128 137 133 1994/95 1995/96 1996/97 1997/98 1998 /99 1999/2 Kaudulla Minneriya Giritale Parakrama Samudra Cultivation 15
Water Savings - Maha Fig.1 Total Irrigation Issues in Maha Season Intervention 1378 1164 1225 PSS 9 95 28489 35836 Giritale 345 6495 75852 Minneriya 726 2625 28192 572 66212 48461 4125 Kaudulla 432 432 39375 94/95 95/96 96/97 97/98 98/99 Cultivation Kaudulla Minneriya Giritale PSS Cropping Intensity Four Polonnaruwa Systems Cropping Intensity - Polonnaruwa Systems 2.5 2. Cropping Intensity 1.5 1..5. 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 1999/2 2/21 21/22 MINNERIYA KAUDULLA P.S.S. GIRITALE 16
Schemes-Wise Cropping Intensity in Polonnaruwa Systems Kaudulla Minneriya Annual Cropping Intensity 2 1.5 1.5 Annual Cropping Intensity 2 1.5 1.5 Inter-connected Systems Operational complexity prevented water being diverted to Kaudulla in some years Age Group of Rice Cultivars - 22 others, 1% 4-4.5 months, 1% 3 months, 26% 3.5 months, 63% 17
Interventions Examples - Kaltota Sheme Kalthota Annual Cropping Intensity 2 1.5 1.5 Staggering of Season made the cropping intensity increased Rice Production Annual Paddy Production ' MT ' Metric Tons 3,5 3, 2,5 2, 1,5 1, 5 1978 1997 1998 1999 2 21 22 23 Increase in paddy production after 1997/98 with increase of CI 18
Thank You for Your Attention. 19