view on ground of wetland under canopy

Early Wetland Detection

Don’t MIRE your project in a Wetland! National Wetland Inventory mapping is a useful tool in early wetland detection

The National Wetland Inventory (NWI) is a widely used database employed by Wetland Scientists and produced by the United States Fish and Wildlife Service (USFWS) that affords the user an aerial view of locations that may have hydrological conditions conducive to support wetlands.

NWI data are created with the help of detailed analysis of high-altitude infrared imaging. Individuals and computer models are tasked with identifying areas that are wet or are holding water. These areas will then show up as dark areas on the mapping.

Know the data gaps in your National Wetland Inventory mapping

NWI mapping is an excellent tool early wetland detection when it is employed in project planning. However, as the illustrations indicate (Figures 1 and 2), not all NWI mapped wetland data are accurate.

Depending on the time of year the aerial data were obtained, the mapping process could result in showing wetlands where none exist. It could also show areas that tend to be seasonally wet. For example, a very wet spring could result in the misidentification of the area mapped in Figure 1. As you will see in Figure 2, this area is, in reality, a soybean field.

Figure 1. Wetlands shown on NWI Map.

Figure 2. Actual view on the ground, a soybean field.









Another important NWI data gap in early wetland detection consists of forested wetlands. These tend to be under-represented (appear smaller) or are not captured at all in the NWI data. As the images illustrate in Figures 3 and 4, the canopy is so thick that the infrared camera cannot penetrate the vegetation.

Figure 3. Forested canopy hides a wetland from NWI cameras.

Figure 4. Actual view on the ground of wetland under canopy.










At ASC Group, our staff of experienced wetland professionals work with you and your project team to fully understand your wetland data. The NWI is a critical tool, but it should be employed early. It should also be used in combination with all other available additional data in order to augment the accuracy of interpretation.

The skills of our staff permit ASC Group to bring more accurate decision-making tools to your projects. We fully understand the NWI data gathering process. Our team interprets those data early in the wetland detection process to keeps your projects on time by eliminating unnecessary surprises.



Read more about wetlands for development in Don’t MIRE your project in a Wetland!