Disclaimer: As always, I need to start out this article with a disclaimer. I know enough about many of these topics to be dangerous – which is dangerous. Always seek the advice of appropriate professionals as this information is subject to change as well as my own interpretation. I don’t often go back and update old articles, so I’ll leave this here.
Wetland should not be confused with floodplain. Flood zones are not always wetland, and wetlands are not necessarily in floodplains. Flood zones normally occur in areas next to bodies of water or runoff areas and are often considered higher risk when it comes to flooding. However, any property can flood, not necessarily only properties in a floodplain or a wetland.
How to Identify Wetland
Wetland can occur even in areas not directly adjacent to a body of water and is usually determined by three primary factors:
1) Hydrology: Hydrology indicators can include the presence of surface water or wet soils as determined by evidence or review by a wetland professional utilizing different tools or testing to understand the presence of water.
2) Vegetation: Roughly a quarter of the plant vegetation species in the United States grow in wetland areas. Plant species can be classified in a number of different ways as identified below in order of wet to dry:
- Obligate Wetland (usually very indicative of wetland areas) ie Sedges (which have triangular, sharp stems) and Willow
- Facultative Wetland (usually occur in wetlands, but occasionally found in non-wetlands) ie Horsetail, Baltic Rush
- Facultative (equally likely to occur in wetlands or non-wetlands) Meadow Foxtail, Timothy, Brome, Bluegrass
- Facultative Upland (usually occur in non-wetlands, but occasionally found in wetlands) ie Potentilla
- Obligate Upland (almost always occur only in non-wetlands) ie Sheep Fescue
3) Soils: Wetland soils are often referred to as hydric soils. These soils can be analyzed by digging a hole (usually 12-18 in deep) and looking at indications of saturated soils that usually show indications of oxygen depletion. This can be evidenced (essentially) by rust in the soils and the coming and going of water, creating oxidation. Oxidation can be due to iron and is usually identified by orange flecks in the soil or manganese which will reveal itself with a purple color.
Can you build in Wetland?
Wetland areas do require special permits and approvals. But first, they must be identified as wetland, usually by way of what is referred to as a Wetland Delineation performed by a properly trained wetland Consultant.
If a particular property shows indications of wetland, Teton County, Idaho will generally require a Wetland Delineation. They have requirements of 50′ or 100′ setbacks, depending on the delineation findings. If the project looks like it will encroach within 50′ of wetlands as indicated by the Delineation, the county may require a Jurisdictional Determination (JD) from the Army Corps of Engineers. If there are any questions on a project, despite setbacks, the Teton County Planning Staff may still send the information to the Corps for review. A JD is the process of Determining whether areas indicated as wetland are regulated by the U.S. Army Corps of Engineers under section 404 of the Clean Water Act and/or Section 10 of the Rivers and Harbors Act.
If a property is determined to be wetland, with the proper permits it may be possible to impact up to 0.1 acre of wetland for driveway, septic, and a home site. If wetland is mitigated to another area, these improvement areas can be increased to 0.5 acres.
Wetland areas can make tremendous home sites, but it is important to remember the reason that these regulations exist in order to protect wildlife, habitat and waterways, often considered a key cornerstone of Teton Valley’s natural beauty.
- 1998 Edition of the US Army Corps of Engineers “Recognizing Wetlands” document
- Teton County, Idaho Planning & Zoning
- Teton County, Idaho Land Development Code (current)