Volta basin 2030: needs, opportunities and risks

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This was presented at the Basin Focal Project Review meeting held in Cali, Colombia from 1-5 Feb, 2008

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Volta basin 2030: needs, opportunities and risks

  1. 1. Volta b i 2030 V lt basin 2030: Needs, opportunities and risks" Cali February 2008
  2. 2. Volta Basin area : 395 000 km2 Burkina Faso Population (2007) 20 M Ghana Data mainly from Ghana and Burkina Faso Faso, The Volta basin : 6 countries Cali February 2008
  3. 3. Within basin Dissemination pathway Go e Government : e t Outside the basin Relevant Ministries, BFP Volta Scientific Departments community and Agencies CPWF (MDA) Institutions for District Di t i t water management assemblies at basin scale Donors Traditional VBA bilateral, bilateral Heads (Chiefs) international ECOWAS-WRCU Development agencies WRC x 6 NGOs Farmers/Water VRA Ghana users associations Cali February 2008
  4. 4. Water Water productivity Water and poverty Poverty P t Food production Institutions Scale : the basin time : present and trends 2050 Cali February 2008
  5. 5. The challenge (1) Volta Pop. Starchy food Starchy food basin ( x106) produced needed (kcal x 1012) (kcal x 1012) Year 2005 19.5 21* 17 2025 32 ? 28 2050 50 - 60 ?? 48 plus possible climate change impact Cali February 2008
  6. 6. The challenge (2) The Global scenarios for SSA to 2050 (SRES and Millennium Assessment ) : • the demand will not be matched by an increase in domestic agriculture p g production, , although • higher levels of agriculture productivity growth compared with north western regions, • the relatively lower level of productivity from which SSA region is starting explains much of this difference. i i t ti l i h f thi diff Cali February 2008
  7. 7. Two main priorities The rain fed food crops in the semi-arid area The water uses in the basin Cali February 2008
  8. 8. The rain fed food crops in the semi-arid area p present distribution yields water productivity rural poverty l t in f d i food crop production d ti in fisheries in livestock production p the ways out of poverty: diversification (small scale irrigation ..) ) intensification (...) Cali February 2008
  9. 9. Food production Rain fed = 99 % of total cultivated area Main cropping systems Cereals millet sorghum maize rice Rootcrops yam cassava plantain ( data from MOFA and MAHRH) Cali February 2008
  10. 10. The Th agroclimatic zones li i and rainfall -Sahel -Sahelo-sudan Sahelo sudan -Sudan -Guinean Cali February 2008
  11. 11. 500 - 900 mm 900 - 1100 mm > 1100 mm % of cultivated area for the different crops along the Cali February 2008 climatic gradient
  12. 12. The increase in production results from increase in cultivated area, not from increase in productivity. p y Data for the Ghana and Burkina parts of the basin, 1992-2004. Cali February 2008
  13. 13. The cropped area as % of total land Cali February 2008
  14. 14. 2,5 Y Maize (t/ha) 2 1,5 15 1 0,5 0 Rainfall (mm) 400 900 1400 Production data from Ghana and Burkina Faso, 1990-2002, rainfall from CRU Cali February 2008
  15. 15. 0,4 WPr maize kg/m3 0,3 0,2 02 0,1 , 0,0 Rainfall (mm) 400 900 1400 Cali February 2008
  16. 16. 2,5 Y millet t/ha 2 1,5 1 0,5 Rainfall (mm) 0 400 600 800 1000 1200 1400 1600 1800 Cali February 2008
  17. 17. 0,4 04 WPr millet kg/m3 0,3 0,2 0,1 0 Rainfall (mm) 400 900 1400 1900 Cali February 2008
  18. 18. An analysis of rural p y poverty in Burkina Faso y data from TASIM-AO project 3 regions, 6 villages in each 30 households in each The study was based on the food sales from the Households in order to evaluate the inland market possibilities The results are by quartiles of the total, plus the upper decile Cali February 2008
  19. 19. Poverty incidence in Ghana Burkina Faso and Togo Cali February 2008
  20. 20. Cumulated cultivated area as a function of the household sales. The three lower deciles cultivate 10 % of the land, while the upper d il cultivates 30 % of the land decile l i f h l d Cali February 2008
  21. 21. From Q1-Q2 to Q3-Q4 Total sales +++ area +++ Water/irrig ++ Family manpower ++ Family manpower/ha -- Hired manpower days/ha +++ Inorg. fertilizer % ++ Draught power % ++ Draught power number ++ Cattle +++ Small ruminants ++ Credit use % + Family credit % ++ Institutional credit % + Cali February 2008
  22. 22. 2 Total sales ( CFA ) 1,6 3000 USD 1,2 12 Fada 2000 USD Kaya 0,8 Dédougou 0,4 1000 USD area (ha) ( ) 0 0 5 10 15 20 Cali February 2008
  23. 23. InorgFertilizer(% of farms)= f(ha) 100 75 Fada 50 Kaya Dédougou 25 ha h 0 0 5 10 15 20 Cali February 2008
  24. 24. The main constraints to the increase of production for food sales (from TASIM-AO, 2005
  25. 25. PN5 experiments Northern Ghana 1800 1600 1400 1200 g/ha No fertil. 1000 Yield kg Micro-dose 800 Full dose 600 400 200 0 Maize Millet Sorghum Effects of fertilizer on crop yields central Volta basin yields, (from CPWF PN5) Cali February 2008
  26. 26. Modeling f tili M d li fertilizer impact on yields i t i ld and water productivity Cali February 2008
  27. 27. Out of poverty Household water develop affordable access to good d l ff d bl t d quality (health etc.) Intensification = better use of rainfall Increase power, tools, land, yield, decrease vulnerability draught animals, plough or cart, g ,p g , fertilizers, SWC, rain harvesting (PN47) Diversification small scale irrigation (dry season), large scale irrigation g g cash crop, small ruminants, cattle, processing ( fish, beer ...), fishing ><cultivation Cali February 2008
  28. 28. Lack of access to good quality household water The two darker zones are f more for than 60 % without good access Cali February 2008
  29. 29. Water related diseases : a significant limiting factor The example of malaria High prevalence o e whole bas , g p e a e ce over o e basin, Health system very expensive and poor efficiency Prevention not affordable ( > 1 USD/day) Malaria as cause of 30 % of micro credit failure (Planet Finance), and concern at macro economic state scale Technical solutions exist (ACT, mosquito net, maternal prevention) but poorly applied. Cali February 2008
  30. 30. Basin wide malaria prevalence model ( (from MARA/ARMA Program) From environment, pop density, rainy density season,...) 10% classes To be compared with cultivated area % Cali February 2008 Volta BFP
  31. 31. Three main activities Cultivation Livestock Fisheries Similar status for the poorer : lack of production means and poor labour efficiency Fisheries Social and economic importance of fisheries for the basin Livestock Small S ll ruminants as safety net for many, i t f t tf Intensification needed, with improved use of fodder Present and future export value. p Cali February 2008
  32. 32. Out of poverty Intensification ( = better water productivity) Small farmer fisherman Incentives and credit as f cotton development for = political will With nation wide benefits for the people now and later - Large inland market, - land tenure, market access, inland market development, Cali February 2008
  33. 33. Water productivity The general approach, at the field scale, WP = production/water consumed by the plants Grain , biomass Soil evaporation + evapotranspiration In rain fed agriculture, the agro-climatic regions determine where specific crops can be grown. The p p g field needs a certain amount of rainfall. With a farmer or ecological perspective, rainfall WP is chosen as a tool to measure improvement of a system (Gregory 1988 in Rockström & Barron 2007). WPr WP = production/ rainfall received by the field d ti / i f ll i d b th fi ld Cali February 2008
  34. 34. Water uses in the basin The surface water resource The underground water Surface water allocation Opportunities: irrigation, small scale irrigation, large scale i i ti l l hydropower Volta basin Authority Risks : climate change environmental flows Simulation : two scales • whole basin and Lake Volta • sub-basin and small reservoirs ( need for recent b b i d ll i df t data) Cali February 2008
  35. 35. Where does the water go ? Mostly in the air, Runoff coef. (3 -12 %) Cultivated area = (13.7 % of total) = most of evap. not from cultures Irrigation < 0.1 % of total area Underground xx Cali February 2008
  36. 36. Many of the rivers of the Upper Volta basin used to dry up during part of the year before 1974. Some have become perennial after the construction of hydro- electric reservoirs. Data from Moniod et al. 1977 Cali February 2008
  37. 37. Lake Volta : a major component of the aquatic system 8500 km2, about 140 km3 (three years residence time), and uncertainty about y the fisheries production Ghana Togo Circa 70 000 fishermen Fishing = diversification from MODIS data base Cali February 2008 Volta BFP
  38. 38. nflow to Lake Volta (km3) Observed inflows to Lake Volta (1985-99) 70 60 50 40 30 y = 0 36x - 107 0,36x L 20 R2 = 0,66 10 0 In 200 250 300 350 400 450 500 Rainfall on basin (km3) Observed inflows to Lake Volta as a function of annual rainfall on the basin. Data from Volta River Authority and CRU. Mean inflow : 36.7 km3/y Mean runoff coef : 9.3 % 10% change in rainfall = 39 % change in inflows Cali February 2008
  39. 39. Two questions q • What would be the impact of rainfall change on the availability of water for electricity p y y production ? • What relationship between small reservoirs development and water inflows to Lake Volta ? The approach : A simulation combining river discharge ( (from Mac Kirby) and WEAP for water uses and y) allocation Cali February 2008
  40. 40. Plus 1 ° ITCZ latitudinal shift and d rainfall changes Minus 1° 1980-2000 Our climate change scenario Cali February 2008
  41. 41. Domestic 156 Livestock 71 Irrig. various 242 Large dams 630 Small reservoirs 894 Lake Volta 35000 Basin wide main water uses 1996-2000 uses, Cali February 2008
  42. 42. Akosombo dam and spillway. In March 2007 only 2 of spillway 2007, the 6 turbines were working, and only one in June Cali February 2008
  43. 43. 60 000 Reference scenario 50 000 Wetter scenario 40 000 Drier scenario 30 000 20 000 10 000 0 0 2 4 6 8 10 12 14 16 18 20 22 Year of simulation Inflows to Akosombo as simulated by WEAP in the three scenarios. The main variability remains dependent on the year to year rainfall variations. Cali February 2008
  44. 44. 160 000 Storage capacity (148,000 Mm3) 140 000 120 000 m3) 100 000 Storage (Mm 80 000 Top of inactive (70,000 Mm3) 60 000 S Top of buffer zone (85,000 Mm3) Reference scenario 40 000 Wetter scenario 20 000 Drier D i scenario i 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Year of simulation But on the long term, there is a progressive increase or decrease in water availability Cali February 2008
  45. 45. Small reservoirs development ( see also PN47) There is a strong demand for new small reservoirs ne reser oirs Present total storage in 2007 is estimated from our calculations as 900 Mm3 for 1600 reservoirs. reservoirs The Th model needs more recent data for the northern basin, d l d d f h h b i because of the hydrological paradox : In dry periods ( post 1972) the runoff coefficient has almost doubled compared with the wetter period (pre 1972) in the basin with a rainfall below 750 mm/y. In Wayen, the coefficient changed from 1.4 to 2.8 Another approach indicates that the volume of the reservoirs is substracted f i i b t t d from th fl the flow to Lake Volta. t L k V lt Cali February 2008
  46. 46. Outputs of BFP Volta Portofolio of research and development activities for VBA, UCRE, funding agencies, NGOs and technical ministries : - underground water resource, - institutions changes for land tenure, investment - livestock (transhumant) status enforcement, ( ) - bush fodder, - weather forecast (AMMA) and practical use, - fisheries monitoring (how) and improvement, - further developments of allocation model within climate and population change, at different scales, addressing local and transboundary issues, More on social acceptance/enforcement Ouagadougou November 2007
  47. 47. Water availability: Climate change (past and future), Rain season variability and forecast, forecast Surface/underground resource and variations as a f function of land cover and land use, ti fl d dl d Impact of reservoirs on the water availability p y and transnational agreements Water budget budget. Socio-economic analysis of hydropower generation compared with other water uses. d ith th t Ouagadougou November 2007
  48. 48. Agriculture : - soil and water conservation techniques * (cost in labour, e.g. zaï only on most degraded soil and high pop density, 1.5 % of cultivated area), - f tili fertilizer use, socioeconomic i i - groundwater use - irrigation potential Development of small reservoirs for small irrigation irrigation. Social management of large schemes Water W t quality as a result of pesticides.. lit lt f ti id Ouagadougou November 2007
  49. 49. Volta basin institutions (1) Dual D l system with t ith Legal state g and traditional hierarchy y low enforcement power land tenure and water access conflicts use one against the other Progressive shift from one land tenure to the other ?? P i hift f l dt t th th = the poor maintained poor insecure land tenure, small investment on water and soil conservation techniques or fertilizers Ouagadougou November 2007
  50. 50. Volta basin institutions (2) Health system to be improved, by capacity building and public awareness, Basin scale Volta basin Authority being created, and WEAP for water allocation between power generation and irrigation Market access, for cash crops (eg cotton) and meat, and in-basin market development for food crops. Ouagadougou November 2007
  51. 51. Within basin Dissemination pathway Go e Government : e t Outside the basin Relevant Ministries, BFP Volta Scientific Departments community and Agencies CPWF (MDA) District Di t i t meetings assemblies Donors Traditional VBA bilateral, bilateral Heads (Chiefs) international ECOWAS-WRCU Development agencies WRC x 6 NGOs Farmers/Water VRA Ghana users associations Cali February 2008
  52. 52. Thank you Cali February 2008
  53. 53. The uneven distribution of towns and population density in Ghana and Burkina Faso Cali February 2008
  54. 54. Rural Poverty y Why Water related Poor water productivity (yields) Rain fed dominance, rainfall quantity and variability risk avoidance low yields health (malaria), domestic water ( ( ) (diarrhea)) human power decreased low yields access to water for livestock conflicts Non water related Poor soils, degraded soils, Low work power Institutional, Land tenure, access to water, micro credit not for agriculture, tenure water agriculture cash crop market low (cotton), access to fertilizers, Why? Solutions and techniques available but lack of implementation Cali February 2008

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