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A Water and Food Security Planning Tool
PODIUM – the Policy Dialogue Model – runs on a personal computer. Policy makers and planners can learn to use it in minutes, to explore vital questions such as: Can we feed ourselves in 2025? and Do we have enough water to irrigate the crops needed to ensure future national food supply and/or food security?
The model maps the complex relationships between the numerous factors that affect water and food security, and displays information clearly, in both graphic and tabular formats. Projections for 2025 are determined in relation to 1995 data. Users can revise this data and change any of the variables used by the model.
Using PODIUM, you can set goals, such as food production for an adequate level of per capita consumption, and explore ways of meeting that goal: through increasing irrigated area, rainfed area, cropping intensity or importing more grain. You can also develop likely scenarios in terms of population growth, diet and developments in agriculture and water resources; then determine the necessary steps to ensure food security and sustainable water use.
PODIUM can help explore critical planning questions such as:
- How much improvement in irrigation efficiency would be needed to cover all Indonesia's additional water requirements in 2025?
- What would be the required rainfed crop yield in India if all additional cereal requirements were to be met by increases in rainfed productivity?
- How much grain
would Sudan have to import to feed its population in 2025, if there is
no new investment in developing additional water
resources?
How does PODIUM work?
PODIUM takes the user through three basic steps:
Step 1: Determine
national cereal requirements.*
Step 2: Estimate cereal
production.
Step 3: Convert the predicted grain production into
irrigation water demand and compare with available renewable water
resources.
*In the current version, PODIUM focuses on cereal crops. This works well for Asian countries where a major proportion of the diet is derived from cereals, and most irrigated land is devoted to cereal crops. To more accurately reflect food consumption and cropping patterns in the Middle Eastern and African countries, IWMI is currently expanding the model to allow for a wider mix of food crops, including vegetables and root crops.
Step 1: How much grain will we need in 2025?
PODIUM determines national grain requirements based on assumptions about population, daily calorie intake, diet composition, and import-export volumes in the year 2025.
An example scenario: Cereal requirement for India in 2025
In the scenario envisioned here, calorie intake increases from 2,394 (the value for 1995) to 3,122. There is a shift towards consumption of more meat products (from 7% of total calories in 1995 to 8% in 2025) and less cereal (from 63% of total calories to 57%). Import and export volumes are assumed to remain constant-100% of the volume in 1995.
Here, India's domestic grain consumption increases from 172 to 303 million metric tons. The country would need to produce an additional 130 million metric tons of grain to feed its population in 2025.
What if Indian dietary habits in 2025 were closer to those of present-day Americans'?
In India, as in most of the developing world, livestock is left to graze (or, in urban areas, forage)—costing little in the way of grain inputs. But if the demand for meat products greatly increases, the available grazing areas will not support all the additional livestock needed, and feed grain requirements will rise.
In the US, it takes an average of 1.63 kilograms of grain to produce 1,000 calories of meat. If we change the default feed-meat conversion ratio for India (0.05 kg of feed grain to produce 1,000 calories of meat) to reflect the more realistic world average (0.73 kg of feed gain for 1,000 kcal of meat), India would need to produce 574 million tons of grain. This is over three times current production levels and almost twice the grain required under the first scenario.
Step 2: Can we produce enough grain to ensure national food security?
The model projects cereal production in 2025 based on the growth in area under cereal cultivation, irrigated area, irrigation intensity, and yields per hectare for both irrigated and rainfed crops. The model calculates projections of average yield, gross irrigated yield, gross rainfed yield, and total production from irrigated and rainfed areas.
Cereal Production in India in 2025
In the base scenario for India, the area under cultivation is assumed to increase slightly. Around 16 million addition hectares are irrigated, with small increases in irrigation intensity, irrigated yield and rainfed yield.
Based on these assumptions, India is able to produce a total of 257 million tons of grain—12 million tons short of the demand estimated in step 1.
What are the alternatives for making up the shortfall, besides importing more grain?
According to PODIUM, it is possible to achieve national food security by increasing:
- rainfed yield from 1.2 tons/ha to 1.6 tons/ha
- irrigated yield from 2.3 tons/ha to 3.5 tons/ha
- irrigation intensity (reflects the degree of multiple cropping in irrigated areas) from 130% to 147%
- the total area under cereal cultivation by 13 million hectares
- the net irrigated area (the amount of irrigated area under crops in an annual cycle) by 19 million hectares
Step 3: Do we have enough water to produce the crops needed?
Water demand is affected by the area irrigated with groundwater and by surface irrigation efficiency (the amount of water that crops actually need, minus the amount supplied by rainfall, compared to the amount of water diverted for irrigation). Impacts of increased water withdrawals are assessed in terms of the country's groundwater balance.
Water balance
definitions
Primary water withdrawal-total amount of water diverted for irrigation, industry and domestic use, minus water recycled. Recycled water is water diverted for irrigation, or other purposes, flowing back into the river that is 'reused' further downstream.
Total withdrawal:
primary diversions and recycled water. Often, estimates of water use do
not take into account recycling-resulting in an overestimation of water
demand.
Depletion: the use of
water (such as evapotranspiration of crops) that renders it unavailable
for further use.
Groundwater balance: reflects the levels in a country's aquifers. A positive value indicates more water is flowing into the aquifers than is being pumped out. A negative value indicates unsustainable use-more water is being withdrawn than is being replenished.
How much water for industry and households?
PODIUM also considers industrial and domestic demands. The user can specify the amount allocated for industry, the percentage of the population with access to piped water and the daily use per person. Very little of this water is actually depleted; most flows back into the system and is recycled.
India: Water for people and industry
In the example scenario, 100% of the population has access to piped water in 2025 and people are using approximately 26 more liters per day. Industrial water use remains the same. According to these assumptions, 5.8 km3 are depleted by domestic consumption (up from 2.1km3 in 1995) and 1.8 km3 is depleted by industry.
· Question: How much improvement in irrigation efficiency would be needed to cover all additional water requirements in Indonesia?
Answer: 42% to 60%
· Question: How about Egypt?
Answer: 50% to 84%, but environmental problems due to overuse might occur.
· Question: What would be the required rainfed yield in India if all cereal requirements were to be met by increases in rainfed productivity?
Answer: From 1.0 to 2.5 tons per hectare, an increase of 5% annually over coming 30 years. Is this feasible?
· Question: How about Sudan?
Answer: A relative small increase from 0.7 to 1.1 ton/ha (37%) would be sufficient to meet all additional cereal requirements. This seems quite feasible.
· Question: The performance of irrigated agriculture is disappointing. If the yields in the irrigated areas could be increased up to a satisfactory level, no increase in irrigated agriculture would be needed. Is this feasible?
Answer: Use the PODIUM Model to test your hypotheses.
PODIUM was used to explore potential impacts of the water and food security scenarios discussed during the Second World Water Forum. It was also used to generate discussion in the eight regional dialogues held as part of the Vision 2025 exercise.
The International Commission on Irrigation Drainage (ICID) has evaluated PODIUM and is recommending it as a policy tool to its member countries.
India's Central Water Commission is revising PODIUM with more detailed local data to estimate water demands and supply on a state-by-state basis.
The Center for Chinese Agricultural Policy is using PODIUM to analyze data for Chinese provinces and major river basins. The results will help inform the country's water resources policy.
PODIUM has been used in meetings attended by national planners and policy makers in India, Sri Lanka, Nepal and Morocco. IWMI is interested in collaborating with other countries to refine PODIUM to meet their specific needs.
PODIUM was used in IWMI's World Water Supply and Demand Study. This phase of the study focused on 45 countries, which represent all the major regions of the world and count for over 80% of its population. PODIUM showed that by 2025, under the moderately optimistic but realistic assumptions of the IWMI base scenario, 33%, or some 2 billion people, will live in countries or regions with absolute water scarcity. This means they will not have enough water to meet all agricultural, domestic and industrial needs. Some 45% of the population of the 45 countries-roughly 2.7 billion people-will live in areas where water resources must be developed by at least 25%. According to PODIUM's global analysis-17% more irrigation water will be needed for the world to feed itself.
The PODIUM brochure offers much the same information as you will find here with graphic examples in a printable layout.
World Water Supply and Demand: 1995-2025 gives a detailed description of the the PODIUM model and how it was used to calculate water supply and demand for 45 countries.
Water for Rural Development, an IWMI study commissioned by the World Bank, analyzes regional water and food supply and demand scenarios (1995 to 2025) using PODIUM. The report can be downloaded from: http://wbln0018.worldbank.org/essd/rdv/vta.nsf/Gweb/water
The IWMI Research Report Water Scarcity Variations within a Country: A Case Study of Sri Lanka examines the variations of water availability and demand within a country under both present conditions and projected conditions in 2025.
The article Global water shortages and the challenge facing Mexico provides an example of adaptation of the PODIUM model to reflect variations in water scarcity within a country.
The article Podium: Projecting water supply and demand for food production in 2025 presents the modeling strategies adopted in the PODIUM model and the results obtained during the development of the World Water Vision. (forthcoming in Physics and Chemistry of the Earth)
PODIUM has been developed as part of the Vision 2025 exercise by IWMI with IFPRI (International Food Policy Research Institute). It builds on IWMI’s body of research on food and water demands (IWMI Research Report 19: World Water Demand and Supply 1990 to 2025: Scenarios and Issues. Seckler et al. 1998).
| Download your copy of the PODIUM software |
| Download Brochure PDF 942KB ( requires Adobe Acrobat™) |