Water Management in S Sudan- Engineer Isaac Liabwel-Ministry of Water Resources & Irrigation-Apr 06
Water Management in Southern Sudan
A BACKGROUND PAPER PRESENTED BY: Eng Isaac Liabwel-MWRI/GOSS-Juba
AT
A WORKSHOP ORGANISED BY: Nile Trans-boundary Environment Action Project
TOWARDS
Preparation of a National Plan for Environmental Management
IN
Post Conflict Sudan
Khartoum, May 16 – 18, 2006
PART ONE: INTRODUCTORY TOPICS
A) Background Information
Southern Sudan is 0.64106 km2 large, with the whole area distributed in the southern plains of the White Nile and its tributaries. Its population of about one 3rd of the total population of the country mainly depends on crop production, livestock and fishing.
1 Climate
Based on climatic and soils attributes of the African continent, among the Africa’s six divisions, South Sudan has wide range of geographical differences that entail location specific solutions.
The northern parts of Southern Sudan; fall under Sudano-Sahelian Region, within its predominantly dry sub-humid and semiarid, with extensive grazing. From the averages for 1930 to 1960[1] (25 years), annual rainfall of this zone has declined. Hence, this zone is characterised by occurrence of dry spells, especially in the first months of the rainy season. Also, in the 2nd half of the season, the zone is characterised by heavy and stormy rains of short duration, hence the rate of precipitation greatly exceeds infiltration rate into its flatlands. In addition, these heavy rains coincide with high river inflows, resulting in an extensive flooding for long periods[2].
The southeast and eastern parts; fall under dry sub-humid and semiarid mountainous East Africa, with potential for tropical rain-fed annual crops.
The southwest and western areas with good drainage conditions; fall under the Humid Central Africa, within its predominantly moist sub-humid and humid of wide range of perennial tropical crops and extensive areas under forest.
The climate of the South in general is seasonal with considerable annual variations, and its mean temperature is greater than 25 oC, hence generally a warm thermal zone[3]. It is characterised by single rainfall season, therefore a pattern of one growing period that becomes shorter northwards. As a result, in the semiarid and dry sub-humid zones, precipitation exceeds half the potential (or open water) evaporation for six months (chart below), which allows for a maximum growing period of around 180 days. And in the moist sub-humid zone, precipitation exceeds half the potential evaporation for nine months, allowing for a growing period of about 270 days. But, latter reports assert that growing season in Southern Sudan ranges from 150 days in the swamp plains northwards with a maximum of 850-mm/annum rainfall to 240 days in the green belt zone southwards with 1,800-mm/annum rainfall (FAO, special report on Southern Sudan, November, 16, 1998). Hence, a trend towards shorter single rainfall seasons that continues from the South to the North.
Chart[4] of Rainfall & Evaporation over and River Discharges into Swamps and Marshes of Southern Sudan
2 Water resources potential
Southern Sudan has substantial water resources but these are unevenly distributed across the territory and vary substantially between years. At the same time water demand for both domestic and productive uses is expected to grow rapidly in the near future. Activities of these demands are likely to impact on both the availability and quality of water resources.
2.1 Surface Water
Southern Sudan is where the main White Nile tributaries meet, and it contributes to the Nile water by the flow from Bahr el-Ghazal basin, the Pibor sub-basin, Bahr el-Jebel torrents and the seasonal streams that flow into the White Nile and its tributaries inside Southern Sudan. When high river discharges coincide with the peak of rainfall, water spills over the banks of rivers; spreading into large areas, which are relatively flat and lower than banks of the rivers, creating swamps whose area is approximately 0.03106 km2 (3 million ha) of which 1.4 million is seasonal and the rest of 1.6 million is permanent. Therefore, only part of river discharges entering the area flow out, hence the region was termed Sudd (barrier/blockage in Arabic Language). The swamps and marshlands of Southern Sudan known as the Sudd region, were described by Sir William Garstin (1908-1909), a hydrological engineer and colonial administrator of the time.
“They are a huge area of vegetation, he said, which can absorb and dissipate half or more (16.9109 m3) per year on average, of the water it receives.”
In the region there are varied features of river system, comprising of perennial rivers, lakes and swamps/marshes; seasonal pools/ponds, rivers, torrents, streams, swamps/marshes and extensive floodplains (known as Toch as they are called by the indigenous); and cataracts/falls/rapids upstream of the rivers.
2.2 Groundwater
It is believed that Southern Sudan possesses large areas of land underlain by rich aquifers, including the Umm Ruwaba formation and some of the fractured and weathered zones of the Basement Complex formation. These water-bearing formations are recharged by seasonal rainfall and river flooding and extend to external areas of the region. Unfortunately generally in Sudan these rich and renewable aquifers, in addition to some springs are not yet fully determined.
Only little information is available about distribution, characteristics, annual extraction, annual recharge, depths, associated risks (sources of pollution) and directions of flow of these underground waters. Therefore, more researches are required in this field, to reveal this potential water resource, which is essentially required to address water shortages in the areas where there are no surface waters; in addition to areas in which the quality of surface water cannot be safeguarded.
2.3 Utilisation
Compared to its neighbours, water resources in Southern Sudan remain underdeveloped, and much of the sparsely existing infrastructure is not efficiently functioning.
2.3.1 Domestic Water Supply and Sanitation
Despite some developments that took place over the last few years, in ensuring access to safe water sources for humans through projects implemented by governments of Sudan, UN Agencies and NGO’s. Yet, the levels of water supply and sanitation coverage are still far from adequate. The vast majority of the population do not have access to reliable supply of safe water and only a few have access to basic sanitation facilities (UNICEF WES database latest figures). Indeed, coverage of access for the population to safe water sources is distributed unevenly over Southern Sudan, ranging according to UNICEF database, from 300 to 70,000 people per water point.
2.3.2 Irrigation
Based on different less advanced techniques, to some extent in Southern Sudan water management has been introduced, to play a role in agriculture, by controlling and exploiting water for farms and crops, hence:
On traditional basis, in the dry season, at fishing and dry season settlements along rivers, tobacco and vegetables are irrigated; maize and cowpeas are planted in the moist soils left by receding river flooding (basin irrigation), which have highly fertile soils with high moisture storage capacity. Indeed, farmers exert effort to irrigate already dried lands or supplement moisture residue of the soils with water from rivers/lakes or hand-dug wells, using manual water lifting and carrying facilities. Also, in the wet season, rice fields are supplied with flooding waters (flush irrigation) while sugarcane and banana are grown on the dikes that protect fishing camps and lowland settlements. Hence, farmers are conscious of the critical role irrigation plays in securing food, especially in the drought-prone areas.
On modern basis, a number of very small-scale all year irrigated gardens exist at major towns, producing vegetables and fruits. These activities are alongside with the successful trials carried out in 1970s by the Department of Agriculture of the Regional Government of Southern Sudan (1972-83) on the experimental irrigated farms of rice, cotton and sorghum at Malakal, whose calculations of irrigation requirements to supplement rainfall resulted in a cropping area of 0.56 feddan (0.23 ha) per 103 m3 of irrigation water, compared to 0.27 fed (0.11 ha) per 103 m3 of irrigation water at Medani (Howell, Lock and Cobb, 1988).
Therefore, 1 fed (0.42 ha) requires 1.8*103m3 of irrigation water in Southern Sudan and 3.7*103m3 in Central Sudan. Hence, the anticipated net water use of the projected area of about 270*103 ha (648*103 fed[5])by the year 2001[6]as part of overall plan for irrigation development in Sudan before war broke out again in 1983, would have been about 1.2*109 m3 (1.2 milliard (billions of cubic metres) as measured at Sennar), and not 0.5*109 m3 as documented in the 1979-volume 3 consultants report. Further, the figure is to be multiplied by 2.2 (divided by 0.45, 50% between Mangalla and Malakal and 10% between Malakal and Central Sudan the acknowledged transmission losses by the Ministry of Irrigation and Water Resources of the Government of Sudan), leading to 2.7 milliard water rights for the then earmarked area at Sennar (2.4 at Aswan).
Notably among these projects is Mangalla Sugarcane Scheme in Central Equatoria, Penko (Penykou) for different varieties of crops in Jonglei and Aweil Rice Scheme in Northern Bahr el-Ghazal (map below)[7]. Before it is disturbed by war Aweil Rice Pilot Project, with financial support from UNDP, FAO and technical guidance of Euro-Consult on infrastructure network, did progress[8], to an existing area of 1,100 ha (2,640 fed) with a recorded yield of 3 t/ha, in the first half of 1980s. The scheme was then to be extended to cover an area of 2,440 ha (5,856 fed)[9].
Out of 84 milliard, total of Nile waters(as measured at Aswan in Egypt), Sudan share is dictated by the 1959 Nile Waters Agreement with Egypt as 18.5 milliard (at Aswan)[10] and it is estimated at 20.5 milliard when measured in central Sudan (at Sennar). Based on this share of water and the above-calculated irrigation water requirements of the country; in addition to suitability of land topography and soil type, across Sudan the area designated for irrigation development is approximately a total of 1.95 million ha of land (4.68 million fed), inclusive of large-scale schemes on modern basis and small-scale schemes that include traditional irrigation holdings.
Consumable share of Southern Sudan from the 18.5 milliard would be based on the 2.4 milliard plus the amount drawn by the pumps in Northern Upper Nile and amount of water for irrigating tea & coffee in Equatoria; in addition to an amount needed for conservations, industry, domestic use and future expansions. Excluded is the hydropower development, which would be utilising regulated natural flow of the downstream users.
During war the tenants and personnel of the previous Aweil Rice Scheme, introduce growing of rice in the northern floodplains of River Loll. And, with help of UN Agencies, NGOs and CBOs that intervened to support this self initiative, small-scale demonstration rice farms have been established along River Akuem in AweilEastCounty by local households. These farms are being expanded locally and replicated elsewhere e.g. Aweil North, Aweil South and YirolEastCounties. Also, GOS has been managing individual irrigation pumps in Northern Upper Nile.
Map of the schemes upstream of Malakal
2.3.3 Hydropower
There is no any hydropower station existing in Southern Sudan, but there have been plans to generate power from the cataracts ofFolaFalls below Nimule and Baden Rapids above Juba.
B) Objectives
In the history of the subsequent Governments of Southern Sudan; a department or a directorate; let alone a political fort-polio responsible for Water Resources never existed. However, there has been a mentioning of an irrigation unit under agricultural establishments and water supply for domestic use under Rural Development and Housing. The CPA enshrined rights in sharing wealth and accessing resources, which culminated in the establishment of the Ministry of Water Resources and Irrigation by the Government of Southern Sudan. Coming to existence of this ministry will enable articulation of water resources development and management, including irrigation and drainage that is an important tool for rural development and jobs creation in most of the developing countries.
This document is meant to reflect specialty of the hydrology of Southern Sudan, water use and water rights; with an ultimate aim of highlighting appropriate solutions, in addressing extremes climatic, topographic and hydrologic scenarios of the area. These specialties and extremities include:
- Coincidence of the peak of rainfall in July and August with the high river inflows from the most upper catchments on one hand; and its flatness that allows for extensive flooding on the other, causing hazards to cultivation at its growing stage; in addition to impediment of livestock production and fishing activities within most of the areas.
- Coincidence of low rains with high evapo-transpiration.
The ministry seek to carryout following prompt actions, in remedying dual problems of recurrent droughts and periodic floods:
In the areas adjacent to river floodplains, where farmers cultivate short maturing variety sorghum, with a possibility of the floods coming before maturity of their crop, remedy entails dike-out of water accordingly in managing coincident of flooding with growing stage.
In the lowlands where farmers make use of flooding to supplement growth of rice, there must be a proper control over water, in managing dual problem of draught and excessive flooding that is being faced, in terms of timing and size of floods. Required technique on one hand could be mere construction of small to medium earth structures to collect and store runoff during heavy rains, so as to supplement crop water requirements. On the other hand, dikes could be made to protect farms against excessive river flooding, hence regulating amount of water getting into the fields. Besides, these dikes’ systems, there is a need for standby pumps to supplement the crop with water in the event of low floods and scarce rains.
In the areas where extension of the growing season is possible by planting in the moist soils, left by the receding floods, a period that corresponds to cold wind of the ending and beginning of the successive years (winter). Lined wells[11] would be excavated and constructed into shallow aquifers, so as to produce irrigation water at low cost from local artisans, so as to supplement such drawdown irrigation. Indeed, water lifting would be facilitated with small generator pumps.
In the areas where farmers grow crops in defiance of the hot months of the summer, there would be facilitation with water lifting devices enhanced with drippers/sprinklers in obtaining and distributing irrigation water onto smallholder group farms’ plots.
In the drought-prone mountainous semiarid areas, since lack of water is caused by low water storage capacity, low infiltration capacity, large inter-annual and annual fluctuations of precipitation and high evaporation demand. Then a variety of essential soil moisture and water conservation technologies must be adopted to promote sustainable small-scale irrigation (including watering of livestock and fish farming) on a watershed basis. During rainy season, excess rainwater (runoff) should be stored using suitable water harvesting structures such as low-cost rural micro-dams. In addition, terraces and check-dams could be erected. This process would arrest excessive erosion and would help recharge of groundwater, within watersheds, based on small-scale communal soil and water conservation projects aimed at enhancing farmers’ opportunities for food production.
Areas, whose productivity surpassed subsistence practices, need to introduce modern techniques in agricultural production, instead of traditional dependency on rainfall alone. Indeed, their production could be boosted to supply required raw materials to industry. In this regard, irrigation water provision would be through river diversion structures and water lifting devices, in managing any unprecedented dry spells during months of the season.
PART TWO: DISCUSSION TOPICS
A) Past and Future Plans
Bringing marshlands of Southern Sudan under modern production practices would play an important role in the stable and sustainable socio-economic development of the more than ½ mobile agro-pastoralists of the population who live semi-nomadic life.
Such development plans on one hand, will receive high investment interest due to potentials for expanded and diversified production activities; but will also face environmental outrage, because of its ecological values and tourism opportunities.
1 Previous Works and Similar Experiences
Soundness of a development plan geared towards stabilisation of the economy in the lowlands of Southern Sudan; being irrigation & drainage schemes, hydropower generation installations and navigation provisions is tested against aspects of environmental conservation that include traditional fishing, natural grazing, wildlife habitat and recreation opportunities. A scale of development determines to which degree the integration of the competing concerns can be achieved. Because, large-scale approaches would compromise balancing; for example:
- Putting of a big continuous part of Toch under modern agricultural production is an absolute barring of free grazing, a situation that is certainly intolerable to the agro-pastoralists communities that would be directly involved.
- A flood control mechanism that leaves an extensive area dry, poses a serious lack of water for many water needy; including wildlife and livestock.
When control of the Nile regime was considered for the sake of timed and perennial irrigation in Sudan and Egypt; first of all both countries proposed construction of a system consisting of dams and regulators at the outlets of the equatorial lakes, where the Bahr el-Jebel originates. Later this proposal was dropped in favour of a drainage scheme, by digging a canal through the swamps of the Southern Sudan, to increase the yield of the Nile for irrigated agricultural practices downstream (Asim el-Moghraby, 1982). This brought about a typical example of a water management project based on a large-scale approach, the Jonglei canal stage I & II, aim at reducing the flooded areas of Southern Sudan (swamps) by transporting water to the downstream users on one hand; and achieving development plans of the local area on the other.