Catastrophic Mortality Interpretation Guidance

The Catastrophic Animal Mortality (CAM) Interpretations found in the eFOTG section II are designed to help users locate suitable sites for the disposal of numerous animal carcasses following an event that leads to the death of large numbers of animals. The interpretation for “Catastrophic Mortality, Large Animal Disposal, Pit” or the interpretation using trenches rather than pits is a method of disposing dead animals by placing the carcasses in successive layers in an excavated pit. The carcasses are spread, compacted, and covered daily with a thin layer of soil that is excavated from the pit. When the pit is full, a final cover of soil material at least 2 feet thick is placed over the burial pit. Below are some guidance on using the reports, maps and data that NRCS provides.

The interpretations, reports and data found in section II of the eFOTG are intended to provide a view of the limitations different soil types have for CAM disposal. The several things should be kept in mind when using this information.

  1. These interpretations are based on the characteristic of the soil, including soil depth. In SoilSurveys, the depth of observation is usually, 60 inches for older survey and 80 inches for newer surveys. Below this depth we have no reliable data to indicate where possible problems, such as bedrock or sand and gravel, could be located. Since most pits or trenches created for disposal could be deeperthan the depth of observation, further on-site investigation is highly recommended.
  2. These interpretations do not include other possible locating concerns such as land use, distance to urban areas, transportation availability, etc.
  3. When the soils data was loaded, only major soil components were used, minor components were not used. Minor might have an effect on the final decision on where your site is located but this will have to be taken into consideration when you are on-site.

Found in this section are maps and data that cover the entire state of Indiana. This information is useful in seeing the large picture of soil suitability. The two interpretations, Pit and Trench disposal, each have their own map and dataset. The dataset is comprised of an Excel spreadsheet and a dBase format dataset that we used to create the map. The dBase file can be linked to the SSURGO spatial data available at the Soil Data Mart and can be added to your local GIS system forfurther analysis and use with other data layers. Also found here is the documentation of the reports themselves including what the interpretation is looking at to rate the soils.

A similar data set can be found in the detailed soil properties section of the eFOTG section II under each county name. The data here is similar to the state data but it is county specific and lacks the documentation.

Items that the reports look at include: Cation Exchange Capacity (CEC), bedrock type, depth to cemented pan (fragipan), clay content, excavation hazard, sand content, flooding, depth to water table, organic matter content, surface stones, stones in matrix, depth to permafrost, ponding, rock outcropping, salinity, seepage, depth to bedrock, slope, sodium content, surface shape, and pH. Further discussion of these issues can be found in the Catastrophic Mortality Interpretations Description document found in the eFOTG.

Fuzzy Numbers

Fuzzy numbers are a way to allow membership into a group. In previous interpretations we had “crisp” rating classes, for example – Slight, Moderate or Severe. All soils, regardless of where it fell in the amount of limitations fell into one of these three classes. The fuzzy interpretation generator assigns the soil a number ranging from 0 to 1 to all soils interpreted. If the soil is assigned a value of 0 it is given a rating of “Not Limited”, if the value assigned is 1, then it is given a rating of “Very Limited”. All other numbers are assigned to the “Somewhat Limited” class. Using Fuzzy numbers, essentially the old “Slight” class and the new “Not Limited” class are the same as are the old “Severe” and the new “Very Limited” class. The real change involves the old “Moderate” rating changing to the new “Somewhat Limited” class. Instead of giving all soils the same “crisp” interpretation we can make subdivisions within the class. If a soil was assigned a fuzzy number of 0.1 while it is given a “Somewhat Limited” rating, the low fuzzy number suggests that the limitation is not that severe and might be relatively easy to overcome. A higher number like 0.9 suggest that while it is still “Somewhat Limited” the limitations would be harder to overcome compared to the soil assigned a value of 0.1. For further information, Contact the NRCS State Soil Scientist.

While the reports, maps and GIS compatible files are available on the eFOTG at the State and County levels; similar reports can be generated from the Web Soil Survey (WSS) for localized areas. Once your Area of Interest has been defined, you can find the interpretation under the “Suitabilities and Limitations for Use” tab. Open the Disaster Recovery Planning menu and select the appropriate report to view. The only differencein the maps would be the interpretive groups used in making the maps found on eFOTG are based on the rating value and has a few more classes defined; and the WSS report is based on the rating class itself.