Cyclone Nargis Leaves Its Mark on the Map
By Matt Freeman, Esri writer
 Data from the MODIS and Landsat satellites allow the FAS to produce a map of the cyclone-damaged rice production regions of Myanmar. |
With 132-mile-per-hour winds, Cyclone Nargis, a category 3 tropical storm, struck the low-lying and heavily populated Myanmar coastline on May 2, 2008. The intense storm produced a 12-foot sea wave that flooded an approximate 2,000-square-mile area, home to 24 million people. More than 90,000 people died and 56,000 people went missing in the country once known as Burma.
Adding to the tragedy of the lives lost, the cyclone destroyed much of Myanmar's agricultural economy in the inundated areas. The provinces of Ayeyardwady, Yangon, Bago, and Mon, which account for 58 percent of the country's rice crop, or roughly 6.2 million tons on a milled basis, were inundated with saltwater from the flood. In addition to the cropland damage, many villages were destroyed along with much of the villagers' food stocks, livestock, and farming supplies.
After the storm, the Foreign Agricultural Service (FAS) of the United States Department of Agriculture (USDA) produced a series of commodity intelligence reports focusing on the country's damaged agricultural areas. FAS uses remote-sensing and geographic information system (GIS) software to analyze global crop production capacity, then issues commodity intelligence reports to reveal international crop conditions. These reports contain maps created with geospatial data and the technology found in Esri's ArcGIS software. Published on the FAS Web site, commodity intelligence reports and GIS-based maps help improve foreign market access to American agricultural products, build new markets, improve the competitive position of U.S. agriculture in the global marketplace, and provide food aid and technical assistance to foreign countries.
In the case of Cyclone Nargis, the reports also provide the agriculture industry with a detailed perspective of where remediation efforts need to be conducted before the country can begin to produce a normal rice harvest. See the May 15, 2008, Commodity Intelligence report.
The maps that support FAS commodity intelligence reports include data from various sources. For example, satellite imagery obtained from the National Aeronautics and Space Administration's (NASA) moderate-resolution imaging spectroradiometer (MODIS) satellite delineates the post-cyclone flooding region. Combined with rice land-cover classification data from the Landsat satellite program and the tools in ArcGIS software, maps of the damaged rice production regions of Myanmar are easily created. These FAS-produced maps reveal the cyclone's effect on cropland and livestock, the severity of flooding, and the rate of cropland recovery. The United Nations (UN), nongovernmental organizations (NGOs), and the international agriculture industry have also used these resources to evaluate the scope of the cyclone's impact.
GIS Reveals the Areas Damaged by Saltwater
Due to restrictions imposed by the Burmese military, relief efforts were slow after Cyclone Nargis and little could be done to aid in the recovery of Myanmar's flooded rice croplands, much less ensure a normal harvest. Saltwater is a serious problem for rice cultivation, and Myanmar's inundated fields would need to be drained and flushed with sufficient freshwater before normal cultivation could be considered and normal crop yields could occur. Drainage became a problem even in areas where few farmers perished because the rice fields are designed to store rainfall as freshwater irrigation. Not only did the cyclone destroy lives and property, it crippled the storm-affected regions' agricultural economy.
 A GIS map created 28 days after Cyclone Nargis passed through Myanmar shows the progress of the country's cropland recovery efforts. |
"Our GIS maps and flood classification data show that the areas originally inundated by the storm account for approximately 1.7 million hectares of rice, 24 percent of the national rice area, or roughly 2.5 million tons of rice production on a milled basis," says FAS international crop assessment analyst Michael Shean. "The core region most severely damaged by the tidal wave and high winds, however, accounted for approximately 900,000 hectares of rice land, 13 percent of the national rice area, and roughly 1.35 million tons of milled rice production. In addition, field reports from inside the affected region indicate that within these rice production areas, large numbers of villages were destroyed along with much of their food stocks, livestock, and farming supplies."
In a second FAS commodity intelligence report, issued June 10, 2008, GIS maps showed that approximately 80 percent of the original inundated rice production area was still affected by some degree of flooding. Fortunately, at that time, conditions in the core damage zone had improved considerably, with only 418,000 hectares, or 46 percent of the original area, still showing flood damage.
The June 10 report also stated that Myanmar's heavy rainfall season was approaching and that it was unknown whether the rain itself would provide sufficient aid in diluting the salt levels in inundated fields or in flushing saltwater from affected soils. In the meantime, the Myanmar government began seeking financial aid to acquire 6,000 tons of salt-tolerant rice seeds to sow approximately 100,000 hectares of rice in areas with the worst saline conditions. According to FAS map data, however, this still amounts to only 6 percent of the inundated region.
Assessing Livestock Using GIS
In the farmable areas, the grim tasks of determining how many people died and relocating survivors and livestock continues. A lack of accurate assessments on the ground about basic needs such as food, shelter, drinking water, and farm supplies have made it difficult for FAS or the UN to determine the actual capacity of recovered farming villages and their abilities to cultivate a normal rice crop. Fortunately, livestock source data provided by the UN's Food and Agriculture Organization (FAO) is available. FAS used it to author the Cyclone Nargis Livestock Impact Analysis and GIS map. FAO data indicates that most rice farmers in Myanmar own two water buffalo or cattle to carry out their normal farm operations. Scientists estimate that nearly 200,000 cattle were killed in the storm. The FAS map is useful for prioritizing areas where donated cattle or even gas-powered farming equipment are? most needed.
Post-Cyclone Nargis GIS maps of Myanmar generated by FAS have proven so valuable in monitoring the flood recovery in Myanmar that the agency has received requests from many organizations for customized maps. "Our maps and data layers are available on a case-by-case basis," says Shean. "We have recently been contacted by a couple of UN groups that are interested in our Myanmar flood analysis layers."
As conditions change and new data becomes available, FAS will continue to produce its own GIS maps, perform analysis, and issue commodity intelligence reports focused on Myanmar's rice production regions. For more information about FAS Commodity Intelligence Reports for Myanmar, visit www.fas.usda.gov.
