5 Questions with a Soil Scientist

Published April 8, 2020
5 Questions with a Soil Scientist

Tyler Sgro is a certified soil scientist who can examine soil morphology and determine whether or not it is a hydric soil. This is a huge benefit for the Charleston District when it comes to wetland classification.

Does this soil classify as wetland?

It’s a question regulators at the U.S. Army Corps of Engineers answer on a daily basis and one newly-licensed Corps soil scientist and ecologist Tyler Sgro can take to another level.

Consider a formerly forested area, cleared of vegetation and filled with foreign soil material. Before changes were made to the site, did this area classify as wetland? And what clues can the soil provide to help with this evaluation?

Every year, the Charleston District regulatory division reviews thousands of permit applications and jurisdictional determination requests. Some of these projects require an in-depth analysis of prior soil surveys and on-the-ground soil analysis to accurately identify potentially regulated wetlands.

In cases with complex soil conditions, the Corps calls in Sgro to do “mini soil classifications” to examine soil morphology and determine whether or not it is a hydric soil.

Recently, Sgro reached a major milestone in his career: completing the South Carolina licensure process and becoming a state-accredited soil classifier. Now, through his role as a Corps scientist, Sgro can officially classify soils down to their individual series, a unique nomenclature among tens of thousands of soil types.

Though not as applicable to routine wetland regulation, soil classification work gives the Corps a greater ability to understand soil conditions and more effectively identify and regulate important wetland areas.

Sgro is the only soil scientist and licensed soil classifier in the Charleston District and is one of only two regulators licensed by their state to practice soil science in the entire Corps.

Sgro started his career at the Corps in September 2016. He holds a bachelor’s degree in environmental economics from the University of Georgia and an advanced degree in soil sciences from North Carolina State University.

We sat down with Sgro to discuss some of the science behind soil classification and its important role in identifying wetlands.

1. When are soil classifications required?
The regulatory team often looks at a small aspect of typical soil classification, or soil analysis, as part of a permit or jurisdictional determination. During this process, the Corps identifies wetland boundaries and establishes its federal regulatory authorities. The ability to conduct more robust soil classification is extremely important in instances where the landscape was altered improperly without a permit. In these cases, the Corps essentially performs a forensic analysis to get a snapshot in time of the soil’s hydrologic conditions prior to site disturbance. Narrowing a soil down to its classification series helps paint a fuller picture of not only the soil’s characteristics, but also its hydrologic conditions.

2. Why is it important?
It’s important to study soil at the local and micro level. Soil hydrology — or the presence or absence of hydrology at certain depths — can vary up to a few feet depending on time of year, and these soil deviations are not always captured in Natural Resource Conservation Service maps. We’re able to apply a more granular perspective by taking a higher number of soil samples on a given site and consider a site’s geomorphic position by using resource information such as LiDAR. Accurately classifying soil and identifying wetlands are also important to development and wetland restoration projects, because these steps ensure effective restoration of degraded wetlands and helps wetlands serve their purpose of trapping and alleviating floodwaters.

3. How do you determine an area as a ‘wetland?’
The Corps classifies areas as wetland when they meet three conditions: presence of hydrology indicators, hydrophytic vegetation and hydric soil conditions. Generally, soils are considered hydric if they are formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper layers — typically defined as the top 12 inches — of a soil.

4. What is something most people don’t know about soil classification?
In my experience, the greater Charleston region is one of the most challenging locations for wetland identification and delineation. This region has large quantities of water and historically wet areas, has critical flooding vulnerabilities and limited buildable areas, and continues to see a high rate of growth and development. Couple that with the area’s unique environmental conditions, such as temporal variations in the rainy and dry seasons and their effects to soil moisture conditions, and you have a kind of perfect storm, from a programmatic standpoint.

5. What do you enjoy most about working for the Army Corps of Engineers?
The ability to apply my experience and expertise to identify and in a lot of ways protect a valuable and under-served resource is rewarding. I believe a high level of field experience and knowledge are indispensable here in this geographic region, and I believe that this aspect of the work we do is vital to protecting our local communities.