Using eight different government GIS databases our scientists find the subject property and check to see if it’s a known wetland, floodplain, or floodway. We perform rainfall determinations on the aerial imagery and review antecedent precipitation to discover if we are in a normal, wet, or dry season. The first thing we do for a wetland delineation is to check all the Geographical Information Systems (GIS) and databases for insight regarding the target property parcel. We find these databases at the: ArcGIS Clearinghouse Natural Resource Conservation Service (NRCS) Federal Emergency Management Agency (FEMA) US Fish & Wildlife National Wetland Inventory Topographic maps Illinois State Geological Survey (ISGS) Clearinghouse Google Earth United States Department of Agriculture (USDA) Web Soil Survey We find the subject property on each of these maps and check to see if it’s a known wetland, floodplain, or floodway. We perform rainfall determinations on the aerial imagery and review antecedent precipitation for field workdays to discover if we are in a normal, wet, or dry season.
If you’re interested in wetland delineations, there’s a good chance you either own or are thinking of purchasing vacant land. You’re hoping to build on the land and you want to make sure you have enough room to do so without disturbing the wetland. You might want to know what happens if you do end up disturbing the wetland and how that impacts the project and budget.
Read on. I’ll do my best to answer all your questions. If you have more you can always call us.
The first thing we do for a wetland delineation is to check all the Geographical Information Systems (GIS) and databases for insight regarding the target property parcel. We find these databases at the:
We find the subject property on each of these maps and check to see if it’s a known wetland, floodplain, or floodway. We perform rainfall determinations on the aerial imagery and review antecedent precipitation for field workdays to discover if we are in a normal, wet, or dry season.
Our next task is to go into the field and document the data needed to prove the existence or absence of a wetland. The “delineation” part of a wetland delineation comes from defining the boundary between the wetland and the upland. To be considered a wetland, it must include the proper soil, vegetation, and hydrology. All three are necessary and if one is missing*, it isn’t a wetland. (*A small caveat to this rule is for farmland or if the wetland has been intentionally destroyed, you may still have a wetland)
Field scientists walk the property and mark the perimeter of the wetlands, marking them with flags that look similar to utility locate flags.
The wetland delineation report is broken down into three parts; Methods, Results, and Conclusions / Discussion. These reports are typically 50 pages long and include narratives, photos, and results from the desktop analysis.
It’s important to remember the reason we perform wetland delineations is to comply with the regulatory agencies who manage wetland permitting. There are two main regulatory agencies, the Army Corp of Engineers and the county stormwater agency. Cities work with the counties to set city ordinances or they may just default to the county. The top agency is the Army Corp. Counties and cities can be more stringent in regulations but they can’t be more lax.
The wetland delineation report is built to be submitted to the Army Corp of Engineers. They either agree or disagree with the findings of the consultant.
There are three possible states of being for a parcel that has had a wetland delineation performed on it.
A wetland delineation can be performed in 10 to 15 business days depending on weather and access to the property.
This is unfortunately the longest part; it typically takes 45 to 60 days to get an answer from the Corp for a nationwide permit that covers most activities and wetland impacts. It may take longer for an individual permit that requires a unique review of development plans and major impacts on wetlands. Once you have an answer from the Corps, it can take another two to four weeks (or more) to get a permit from the county or local government.
A full wetland delineation starts around $2500 but can cost more depending on the size of the property, predicted wetland pockets, and the distance we need to travel. There are less expensive and lighter options than a full wetland delineation if permitting isn’t the ultimate goal. We can review all the maps and databases for $450 and provide an opinion based on the data. We can also send a scientist to perform a wetland assessment for an additional $600 - $1200 to look for the telltale signs of a wetland. Both options are good due diligence steps before you purchase a property on which you intend to build if you are not yet sure if you need to submit a report to regulators.
The easiest way to build on a property that has a wetland is to avoid building over the wetland. The second way would be to get the appropriate permits which may involve wetland mitigation.