Policy Dialogue Model
Interactive water & food security planning scenario tool

 

Table of Contents

 

 

Overview
Background
What it does ?
How ?
How does PODIUM work?
How can you use PODIUM?
Who's using PODIUM?
The PODIUM - Techinical Documentation

 

1.0       Overview

 

PODIUM – The Policy Dialogue Model, now runs on the web as an interactive scenario development tool. 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. Also allows the users to print reports of the scenarios that they have developed for different types of projections. Regression graphs (trend line graphs) are included for key indicators such as Population, Daily calorie intake, Food/Feed grain consumption, Domestic consumption and etc. Users can customize these regression graphs for a particular a period in order to calculate linear projection for each indicators. The linear projection values will be recomputed by the system dynamically and resets the graphs automatically. 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.

The Policy Dialogue Model (PODIUM) helps countries determine future directions for agricultural and water resources policy by allowing them to explore potential demand and supply scenarios for food and water in 2025.

• If calorie consumption reaches 3000 calories per capita per day and dietary patterns change towards increased meat consumption, how would the national grain requirements change?
  
• Based on this scenario, do we have enough water to produce the crops needed to ensure food security?
  
• What would this require in terms of rain-fed and irrigated grain production?
  
• How would increased water demand affect the groundwater balance?
  
• What are the implications for water resources policy?

 

2.0              Background

 

The policy dialogue model is developed as part of the Vision 2025 exercise through a joint effort by IWMI (International Water Management Institute) and IFPRI (international Food Policy Research Institute).

The model builds upon IWMI's previous research on food and water demand, described in: "World Water Demand and Supply, 1990 to 2025: Scenarios and Issues" by David Seckler et al. (IWMI Research Report no. 19, 1998). This report can be downloaded from IWMI's website IWMI.

At a later stage, the results from IFPRI's model IMPACT will be used to validate and refine IWMI's model. At present these results are not available and data from international databases such as FAOstat, WRI, IRRI/Huke and USDA are used.

• provide an analytical framework to structure discussions about future water and food demand issues.
  
• Generate critical issues which needs further attention and research.
  
• What are the implications for water resources policy?

 

3.0       What it does ?

 

The model determines increasing water demand in 2025 as a result of population growth and changing diets. It gives the user ample opportunity to modify assumptions to the national context and to test different scenarios.

The model does not provide hard and fast predictions but rather analyses "what-if" questions. For example, it helps analyzing and answering questions such as: "If India's population in 2025 will consume 3000 Kcal per capita per day, what does this imply for grain requirements, what does this require in terms of rainfed and irrigated grain production and ultimately, what does this mean for irrigation policy and water requirement? Will water and land resources be sufficient to produce the required food, or should the country import more grains? And what if the calories intake rises up to 3600 KCal (US level) and people start eating more meat? The user can modify all major variables and directly monitor the effects of these changes on water demands. This feature makes the program a very suitable tool for scenario testing and sensitivity analysis. 

 

4.0       How ?

 

After selecting a country, the program loads default data and assumptions. The program uses 1995 as a baseyear. By default, 2025 predictions are based on historical growth rates (1985-1995) derived from the FAO database.

At a later stage results from IFPRI's IMPACT model will be used as default predictions. It should be stressed, however, that users can change all major variables and modify assumptions and predictions according to their own insights and local conditions. The computation process consist of three steps: The first step is to determine the grain requirements (food as well as feed) based on user defined assumptions concerning calories intake and diet composition in the year 2025.

The second step computes the production of the required cereals using data and estimates of yields and cultivated areas with and without irrigation. The third step converts this predicted grain production into irrigation water demands and compares this irrigation water demand with actual withdrawals in 1995 and available renewable water resources. Further, it assesses expected adverse impacts of increased water withdrawals on the groundwater balance. The program takes into account water needs for domestic and industrial uses.

 

 

5.0              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.

 

5.1     Step One : 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.

 

5.2       Step Two : 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 .

 

5.3       Step Three : 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

 

6.0        How can you use PODIUM?

 

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?