Model Results – Water Resources

The results of the modeling of China’s water and agricultural resources show that, based on regional data, there is a surplus of water in China as a whole. In five of the regions, however, all of which are located in northeastern China, water use requirements exceed the sustainable yield and deficits are occurring to various degrees. Because of the water use priority scheme imposed by the model, the impact of a deficit is felt first by the agricultural sector. In two of these regions, the Haihe and the Huanghe, significant and/or ongoing deficits occur in the agricultural sector throughout the study period. In the Huanghe, a deficit also appears in the industrial sector in the second half of the period. In Heilongjiang, Liaohe, and Huaihe, less severe deficits appear late in the period in the agricultural sector. Table 1 presents the expected frequency of each region experiencing a water deficit through the year 2025 as indicated by 100 replications of the model. As shown in the table, the expected frequencies of experiencing a water deficit through the year 2025 for the Haihe and the Huanghe are “always” and “almost always,” respectively. This means that any given model run for these regions will show a deficit “almost every year” or “every year” of the study period, respectively. The other eight regions are expected to experience no or almost no deficits through 2025. These results are presented schematically on the map in Figure 1.

Table 1. Expected Frequency of Each Region Experiencing a Water Deficit
Through the Year 2025 and the End-Use Sector Affected

Figure 1. China’s water situation.

Figures 2, 3, and 4 present the results for the Haihe region. Figure 2 presents a single run of the simulation model through 2025. The figure shows the available water and the breakdown of water use by surface water and groundwater. The run generated a series of correlated random values for annual rainfall and runoff using a normal distribution of historic precipitation and runoff data. The figure also presents two projections of total water requirements for each regions, one generated using agricultural water requirements computed by the agronomic model, the other generated using a linear projection of agricultural water requirements based on data from the China Ministry of Water Resources, Beijing.

Figure 2. Comparison of one replication of a Monte Carlo simulation of available water with two projections of total water requirements in the Haihe region, showing the breakdown of water use by surface water and groundwater.

Figure 5 presents a single run of the simulation model through 2025 showing the available water and the breakdown of water use by sector for the Haihe region. Note that the impact of the deficit is felt first by the agricultural sector; if the deficit were large enough, the industrial sector would be impacted next, followed by the urban sector. As shown in the figure, the urban and industrial water requirements are met through the year 2025. The deficits in the agricultural sector are due not only to the increasing water requirements for agriculture but also to increasing urban and industrial use.

Figure 3. Comparison of one replication of a Monte Carlo simulation of available water with projected total water requirements in the Haihe region showing the breakdown of water use by sector.

Figure 6 illustrates the predicted water deficit for the Haihe region through the year 2025 estimated by generating 100 replications of the simulation model and computing the mean and standard deviation of the water deficit for each year through 2025. Given the model assumptions and available data, the agricultural sector deficit for the Haihe is likely to reach between 22 and 30 billion cubic meters by the year 2025.

Figure 4. Predicted water deficit for the Haihe region through the year 2025 generated in 100 replications of the simulation model.

Because the Haihe region receives interbasin transfers from the Huanghe, deficits in either region are also likely to play a significant role in water scarcity issues in both regions in the coming years. Moreover, because water use requirements exceed the sustainable yield in all regions experiencing a deficit, it is assumed that the deficit must be met by mining groundwater. This assumption is confirmed by reports that groundwater mining is already under way in the most intensively cultivated and populated areas of northeastern China, particularly around the Beijing area.

Results by Infrastructure Model

1. Water Resources
2. Agriculture
3. Energy
4. Greenhouse Gas

For more information contact Dr. Dennis Engi, (505) 845-8284.

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