XI International Conference on Rainwater Catchment Systems August 25 29, 2003 Mexico City, Mexico

Transcription

1 XI International Conference on Rainwater Catchment Systems August 25 29, 2003 Mexico City, Mexico Conference Topic: Rain Water Harvesting For Food Security Title: Water Harvesting and Institutional Strengthening in Tigray Ethiopia Author: Fred A. Kraft, Director International Projects Agriculture and Agri-Food Canada, PFRA Edmonton, Alberta, Canada, T6R 1P2 I. Introduction The Government of Canada through its International Development Agency (CIDA) and Department of Agriculture, is providing technical assistance on water harvesting, to the Government of Ethiopia within the northernmost province of Tigray (Figures 1 and 2). The purpose of the project, entitled Water Harvesting and Institutional Strengthening in Tigray (WHIST), is to improve food security in the drought and famine prone areas of the province. II. Background Tigray, occupies an area of 80,000 km 2 and has a population of approximately 4 million. Most of the people (85%) live in rural areas. Tigray is one of the most drought prone areas of the country and has a mean annual moisture deficit of about 1000 mm in the eastern region. Figure 1 Figure 2 Drought conditions stem from the predictable characteristics of the monsoon rains that follow the oscillating movement of the inter-tropical convergence zone. The eastern part of the province, which lies on the edge of the monsoon coverage, receives approximately 450 mm per year. While drought does not always affect all parts of the region, and some areas may in any given year have a surplus, 1

2 others may have a deficit. In spite of regional areas of surplus and deficit, a natural balance of trade has not developed because of inter-area transportation and marketing constraints. Even in a relatively good year, one family in six may be facing hardships resulting from two years of failed harvest. The latter two successive years of failure, if occurring on a broad scale are sufficient to cause famine. Severe famine occurred in the early 1970 s, again in the mid 1980 s (Figure 3) and there were significant regional food deficits in 1991 and This region only shared marginally in the bumper crops of 1995 and Severe famine occurred again in 2002 (Figure 4). Figure 4 Figure 3 Without drought amelioration, the region is unlikely ever to be food secure. Family household food needs are estimated at about one tonne of grain per household per year. Because of limited farm size, family production varies from 1.4 tonnes in a surplus year to 0.23 tonnes in a deficit year. Drought is sufficiently endemic that sufficient or surplus harvests may occur only about one third of the time. Even when harvests are good, with a national population growth of 3% per year and food production increasing by only 1%, Ethiopia requires one million metric tons of food aid a year. A disproportionate share of this food aid is directed to the province of Tigray (Figures 5 and 6). Figure 5 Figure 6 2

3 Although annual rainfall is insufficient to sustain perennial stream flows, heavy summer rains in July and August cause large seasonal stream flows (Figure 7). Hence there is widespread potential for small storage schemes such as dams and river diversions to water for downstream irrigated food production and domestic use. (Figure 8). Figure 7 Mekelle, Tigray Ethiopia Figure 8 Water availability is the largest constraint to increased food production. The Ethiopian Government and the Tigray Regional Government began to seriously address this issue in the mid 1990 s. The result was an increased emphasis on the construction of small and mid sized dams (Figure 8), river diversions and later, farm and community ponds. At the same time, new technologies related to the irrigation of dry land areas were introduced and an increase in the extension services to irrigation farmers was planned. The responsibility for water resource development and utilization is now shared between the Tigray Water Resource Development Bureau* (TWRDB) and the Bureau of Agriculture (BOA). In theory, TWRDB is responsible for watershed planning and the construction of water harvesting and distribution works. BOA is responsible for irrigation extension and developing local Water User Associations to manage the completed irrigation schemes. It is also responsible for completing the soil conservation works in the upstream catchment area. *formerly SAERT Sustainable Agricultural and Environmental Rehabilitation of Tigray. SAERT was created in 1995 by the Regional Government of Tigray. In 2001, SAERT was dissolved and the former functions were included within the broader mandate of the newly formed Tigray Water Resources Development Bureau (TWRDB) 3

4 III. Tigray Water Resource Development Bureau (TWRDB) Severe famines and water shortages in the early 1990 s caused extreme pressure to be placed on the Regional Government of Tigray and its line departments. The TWRDB was expected to deliver numerous water harvesting schemes often within short and unrealistic timeframes. As a result, projects were often rushed to the construction phase without completed construction drawings. In some cases large water harvesting projects were built without full and complete engineering investigations. This situation was compounded by a general lack of baseline data (meteorology, hydrology, agronomy, etc) and a corresponding over-reliance on empirical and generalized textbook information. The TWRDB is a relatively new organization with professional and technical staff that are technically competent in engineering and agronomic theory, however, practical experience is lacking. Therefore an increase is needed relative to the organization s ability to study, plan, design and construct technically complex water harvesting and irrigation systems. A gap analysis identified several technical issues that aggregated to a serious capacity constraint. This technical gap threatened the viability of the TWRDB s water harvesting schemes that were previously constructed as well as those that were planned. Specifically, there was a real potential for, and some evidence of: 1. problems with construction planning and management 2. highly erosive untreated upstream catchment areas causing reservoir siltation 3. salinization and water logging of command areas, especially on clay soils 4. problems with earth canals:? high water loss through seepage? instability? waterlogging in adjacent areas 5. high maintenance requirements for embankments due to:? insufficient compaction? inadequate water content of fill material? shallow key trenches? over/under estimates of hydrologic parameters? specific assumptions regarding: 1. foundation conditions 2. homogeneity of the compacted clay core embankment 3. slope stability 4. the importance of vertical and inclined filters 4

5 IV. Bureau of Agriculture (BOA) Prior to the Tigray Regional Government s policy direction towards irrigation, the BOA s primary focus was on dryland agriculture. Little if any irrigated agronomy or irrigation extension expertise existed within the Bureau. This capacity constraint also threatened the long-term sustainability of past and planned water harvesting and irrigation schemes. Specifically there was evidence of: 1. rapid salinization of irrigated command areas 2. severe erosion in catchment areas 3. inability of farmers to operate irrigation schemes 4. inefficient use of land and water 5. reservoirs quickly filling with silt 6. irrigated produce marketing issues V. Water Harvesting and Instituional Strengthening in Tigray The WHIST Project The WHIST Project is a capacity building initiative. The goal is to improve the technical capabilities of the Tigray Water Resources Development Bureau (TWRDB) and the Bureau of Agriculture (BOA) in the aforementioned areas of deficiency. The desired project outcome will be institutions that are highly capable of planning, designing, constructing and effectively managing, sustainable, community based water harvesting and irrigation systems. VI. Capacity Building Methods Several methods have been utilized to increase the technical capacities of TWRDB and BOA staff relative to water harvesting and irrigation. They are: 1. Involving TWRDB and BOA senior managers and technical specialists in a participatory Results Based Management exercise to set clear goals, roles and realistic expectations. 2. Hosting technical study tours to Canada to demonstrate modern irrigation practices as well as the engineering and agronomy activities associated with sustainable irrigation development. 3. Supplying technical library materials to provide quality reference materials for technical specialists. 4. Funding further education at foreign institutions in disciplines that need added technical depth. 5. Providing short term (3 months) and full time technical specialists to coach and mentor individual technical specialists. 6. Developing and documenting standardized procedures for key technical activities. 5

6 7. Providing technical experts to deliver classroom (Figure 9) and field training (Figure 10) to groups of Ethiopian trainers on specific and relevant engineering and agronomy topics. 8. Identifying pilot sites for in-field demonstrations and detailed study of specific technical issues. 9. Supplying technical equipment and related training for scientific investigations (geo-technical drill rig and truck, laboratory equipment for soil physical and chemical analyses, in-field water sampling and analyses kits, salinity measurement instruments). Figure 9 Figure 10 VII. Skill Development Areas 1. Engineering? Geo-technical? Geology? Hydrology? Hydro-geology? Hydraulic structure design (Figure 11)? Surveying and drafting (Figure 12)? Construction planning and management (Figure 13) 2. Agronomic? Soil and water compatibility? Extension methods? Soil laboratory operations (Figure 14) 3. Other? Socio-economics? Gender equity? Management information systems? Environmental impact assessment 6

7 Figure 11 Figure 12 Figure 13 Figure 14 VIII. Specific Capacity Building Examples 1. Hydrology Little if any meteorological and hydrological data was available for the Tigray Region. As a result generalized data was utilized for the design of water harvesting structures. This led to over-design and under-design of structures. In the case of over-design, labor, capital and time was wasted, in the case of under-design the structures would often fail. 7

8 To address this deficiency, manual and solar powered hydrologic instrumentation is being installed (Figures 15, 16 and 17). The Ethiopian engineers and technicians are being trained to operate the equipment and to analyze and use the resultant data to improve the designs of their water harvesting works. Figure 15 Figure 16 Figure Geo-technical Dam Construction Numerous small to mid size earth fill dams had been constructed prior to the WHIST project. Post construction problems were experienced on several embankments and technical assistance was requested in order to improve the standard of construction on subsequent works. A typical earth fill dam would consist of approximately 1.2 million cubic meters of earth fill and would impound about 2 million litres of water. The height of the dams would range from 15 to 25 metres. Most of the excavation and placement of fill material was done with manual labor and donkeys. At the peak of construction there would be between 2000 and 2500 people excavating, transporting and placing fill material. (Figures 18, 19, 20 and 21) Many of these were women. Dam construction was generally funded through Food For Work foreign aid programs. Donor countries would provide grain 8

9 and cooking oil. These commodities would be used to pay the labor force for dam and spillway construction and upstream soil conservation treatments. A typical payment for one day of labor was 3 kilograms of grain and 0.5 litres of cooking oil per person. Figure 18 Figure 19 Figure 20 Figure 21 Because of (1) the pressure for rapid construction of water harvesting works and (2) the lack of geotechnical sampling and analytical capabilities, thorough geo-technical investigations were seldom completed. Valiant efforts were made to understand embankment foundation conditions through manually excavated test pit information (Figure 22). Unfortunately, the lack of practical experience in interpreting geo-technical information, when combined with a paucity of collected data and essentially no laboratory analyses, often lead to erroneous conclusions. This frequently resulted in poorly sited embankments based on assumed foundation conditions, key trenches that were too shallow (Figure 23) and slope stability concerns. As a result, many of the embankments are experiencing significant leakage, which is often transporting suspended fill material. (Figure 24) Extensive maintenance will be necessary to preserve these structures. 9

10 Figure 22 Figure 23 Figure 24 The WHIST project is developing the technical competencies of the TWRDB geo-technical engineers. A geo-technical drill rig and truck will be supplied by the WHIST project. Practical training will be provided to an Ethiopian drill rig operator and geo-technical engineer relative to drill rig operation and the collection of undisturbed soil samples. Training will also be provided to geo-technical engineers and technicians with respect to the operation and management of a geo-technical soils laboratory (Figure 25). 10

11 Figure 25 Figure 26 Additional geo-technical training is being provided relative to the proper design and construction of compacted earth fill embankments. Because mechanized compaction, fill watering, and earth moving equipment was not always available; many sites were under-compacted at inappropriate moisture contents. Also, earth fill was often randomly placed rather than in even, continuous lifts. As a result, many dams are experiencing serious settling and cracking (Figure 26 and 27) which threaten the long-term viability of the embankments (Figure 28). Canadian geo-technical and construction engineers are now providing one on one mentoring to their Ethiopian counterparts relative to standard design and earth fill construction procedures (Figures 29 and 30). Figure 27 Embankment Cracking Figure 28 11

12 Figure 29 Figure Soil and Water Compatibility Many of the previously constructed dams were sited in good locations from an engineering perspective. Unfortunately some of these sites were poor locations in terms of soils that were well suited for subsequent irrigated crop production. Several command areas exhibited saline characteristics under dryland conditions. In a number of cases these conditions have worsened after irrigation (Figure 31). Consequently the expected return on investment from increased crop production is not being realized because of the adverse saline effects on crop yield. Some sites will likely have to be abandoned in the future. The WHIST project is now providing technical instrumentation and training for salinity diagnosis, mapping and monitoring to Ethiopian engineers and agronomists (Figures 32 and 33). Subsequent command areas will be selected based on standard criteria for irrigable soils. Dryland saline areas will be delineated prior to irrigation and if small, will be excluded from the command area. If saline areas in the potential command area are large, those sites will be abandoned in favor of other sites with more suitable soil chemistry characteristics. Figure 31 12

13 After irrigation begins, salinity monitoring will be undertaken to ensure that salinity is not increasing from the application of irrigation water. Salinity issues in future projects are unlikely to be serious as a result of increased competencies in this area.. Figure 32 Figure Catchment Area Soil Conservation The demand for cooking fuel (Figure 34) by an ever-growing population has resulted in the removal of most of the tree cover on the Tigrinian landscape. After harvest, cereal crop residue is also removed (Figure 35) from cultivated fields and used for cooking fuel and livestock feed. This material, if left in place, protects the soil from erosion. Tillage of the now bare cropland areas coupled with overgrazing of grassland areas (Figures 36 and 37) leaves the soil further exposed to the erosive forces of wind and especially water. In many areas the fertile topsoil has been totally removed and only the underlying rocky parent material remains. Because this material contains virtually no organic Figure 34 Figure

14 matter it is highly erosive especially in hilly topography. High intensity rainfall (greater than 35mm/hour) is common during the rainy season and causes severe erosion on these landscapes. Figure 36 Figure 37 Numerous dams, weirs, catchments and command areas were located within these areas and serious operational problems resulted from the soil loss and transport. In some instances portions of the command areas have disappeared, in others reservoirs have been abandoned because of excessive siltation while in others, river diversion weirs no longer provide upstream storage (Figures 38, 39,and 40). Reservoir sedimentation rates of greater than 63 tonnes/hectare per year have been documented. Figure 38 Figure 39 14

15 Figure 40 The water harvesting schemes that were constructed prior to the WHIST project required massive investments of donor aid and Ethiopian labor and capital. At the outset of the WHIST Project, Canadian engineers and soil scientists recommended that dam and river diversion construction should occur only after comprehensive upstream soil conservation works had been completed. At that time soil conservation works were being installed in some catchment areas but this effort appeared to be of a lesser priority than the construction of dams. As a result, many reservoirs were developed without the benefit of catchment area treatments. It was pointed out that for these reservoirs, the observed and predicted sedimentation would reduce the design efficiency and useful life of these structures and the planned return on investment would not be realized. For a number of reasons, including the need to abandon some of the initial reservoirs because of excessive sedimentation, the Regional Government of Tigray re-focused its policy on water harvesting. Under the new policy, the Regional Government has introduced a small pond construction program. The purpose of the program is to excavate many thousands, if not tens of thousands of small ponds throughout the most drought prone areas. The ponds are intended to provide domestic water and irrigation water for local gardens. As well, the construction of dams and river diversions is now occurring at a much slower pace and much effort is being directed to watershed soil conservation activities. Most soil conservation works are completed with community labor (Figure 40) that is either donated by the men and women of the community or paid for through Food For WorK programs. A variety of soil conservation activities are undertaken, the most common being the installation of rock bunds on the contours of steep slopes (Figures 42, 43). The bunds slow the movement of water and serve as soil traps. Grass and trees are then planted in the stabilized slopes while indigenous species can grow unhindered. (Figure 44). 15

16 Figure 41 Figure 42 Figure 43 Woodcutting is prohibited and often grazing is as well. Farmers are allowed to come in with sickles and hand harvest the mature grass in selected areas. This treatment is producing remarkable results within a period of a few years (Figure 45). The land is beginning to heal and a corresponding decrease in erosion and sedimentation is being observed. Figure 44

17 Figure 45 The WHIST project has selected two small watersheds that are adjacent to one another, identical in size and similar in topography. After initial groundwater and base flow measurement, one watershed will receive a number of soil conservation treatments. The other watershed will be left untreated and will be farmed in the traditional manner. Instrumentation has been installed on both watersheds to measure precipitation, runoff and groundwater elevations. Runoff sediment load and a number of other parameters will be determined. Figure A Sharp Edge 90 A 3 Section A-A mm thick Steel Plate Compound V-Notch Weir Natural Gully Surface D/S Elevation (all dimensions in mm) Hydrologic and hydro-geologic monitoring on twin watersheds to demonstrate benefits of upstream soil conservation treatments > 1512 Masonry Wall to Attach Steel Weir To mm 5550 Compound V-Notch Weir Installation Detail - U/S Elevation (all dimensions in mm) 17

18 The twin watersheds will be used to demonstrate to farmers, engineers and agronomists, the qualitative and quantitative benefits of soil conservation activities. Data collected from the site will also be used to establish site and treatment specific runoff coefficients and other hydrologic indices for this region of Tigray. IX. Project Challenges to Date Prior to the implementation of the Whist Project, a comprehensive Results Based Management plan was completed in which all stakeholders participated. Clear project outcomes were developed along with the necessary short-term outputs. Roles and responsibilities for each of the several stakeholders were well defined and a performance measurement framework was established. A number of implementation challenges have arisen that were not forecast in the initial planning. They are: 1. A border war between Ethiopia and Eritrea. The detailed project design was completed in early The subsequent outbreak of war in May and June of 1998 and again in February 1999 delayed implementation until early Additional project priorities were identified subsequent to the war. It was determined that these would have to be addressed within the same budgetary envelope (CAN $7.5 million) The result was the shortening of the project by one year. The war also resulted in the diversion of funding for food security initiatives (such as WHIST) to the war effort and to the subsequent repayment of a large war debt. 2. A massive re-organization coupled with an expanded mandate and a 50% downsizing of one of the primary Ethiopian partners occurred in Year 2 of the project. The result was a significant disruption to project management and implementation and progress has been hampered. The loss of numerous key positions and the resulting change of duties for those that remained resulted in an inefficient use of Canadian mentors and trainers. Many of the employees that were previously trained were dismissed in the reorganization and downsizing. Others who were trained were transferred to new jobs that were totally unrelated to their former position. The planned project outcomes and performance targets were based on the initial size, mandate and capability of the original partner organization. Because of a massive re-structuring coupled with an expanded mandate and a 50% staff reduction, project outcomes and performance targets will now likely need to be scaled down. 3. Much higher than anticipated staff turnover rates have hindered organizational capacity building efforts.. Salary levels within Ethiopian regional government departments are low and are not competitive with those of the private sector. Because of the specialized training provided by the WHIST project, many of the trained employees are offered and accept higher paying jobs with the private sector. This phenomenon hinders the development of a critical mass of trained engineers and agronomists within TWRDB and BOA. 18

19 X. The Future The WHIST project is at its mid point. Many successes have been realized in spite of the aforementioned challenges. Much of the focus to date has been directed to the training on and standardizing of, various engineering and agronomic procedures such that representative field data and physical samples could be obtained for further scientific analysis (soil and water chemistry, soil physical properties etc). This activity will continue in the future but a greater emphasis will be placed on training and skill development in the proper methods and procedures to: 1. analyze the collected samples 2. manage the analytical data 3. interpret the data 4. develop sound recommendations 5. make decisions based on the recommendations This strategy is intended to increase the sustainability of water harvesting and irrigation schemes (and hence food security) through the application of practical, science based decision making in the engineering and agronomy disciplines. An additional priority for the second half of the project will be to help the BOA irrigation extension specialists develop community based Water Users Associations. (Figures 47 and 48) The intent is to have each of the water harvesting and irrigation schemes managed by the farmer and community beneficiaries, with a special emphasis on the involvement of women. Figure 47 Figure 48 Performance measurement has also been implemented with initial emphasis on establishing baseline data. This will be followed by regular data collection and analysis to determine the impact of the WHIST project relative to increasing food production in the drought prone regions of Tigray. 19