Delaware Wetlands logo

Facebook  Twitter  Instagram  YouTube  RSS Feed

  Archived Posts From: 2019


Realtors & Wetlands: What you need to know to help clients purchase and build wisely

Written on: February 27th, 2019 in Outreach

by Brittany Haywood, DNREC Wetland Monitoring & Assessment Program

Wetlands are a part of our everyday lives.  They are in the landscape silently helping to control flood waters, clean our drinking waters and protect us from damaging storms.

Knowing what wetlands are, where they are, how they work, and what can and can’t be done with them before property is purchased can save time and money in the long run. Read on to start your journey into Delaware’s wetland world.

Identifying Wetlands on Delaware Lands

Wetland maps

The first and easiest way to figure out if wetlands might be on a property is to look at maps. There are two different wetland map types available for anyone to use for free online. Each serves a different purpose. If there is an area on a property that seems like it should be a wetland, but it is not showing up on a map, you should probably have a wetland delineation performed.

Delaware Wetland Toolbox Map shows wetlands on property

This map shows biologically mapped wetlands (in green) in an area of Delaware using the Delaware Wetland Toolbox.

Biological wetland maps

These maps outline all wetlands using the biological definition of wetlands: wetlands must have water on the surface for some part of the year, hydric soils and hydrophytic plants.

They map all wetland types including tidal and non-tidal wetlands, and serve only as a guidance tool.  If a definitive wetland boundary needs to be determined, a wetland delineation is needed. Remember only certain wetland types are regulated, and just because a wetland is mapped, does not mean it is regulated.  Click on one of the two maps below to get started:

  1. National Wetlands Inventory (NWI) – Wetland Mapper
  2. Delaware Wetland Toolbox

The state regulated tidal wetland maps

An individual map pulled from the state regulated tidal wetland map viewer.

An individual map pulled from the state regulated tidal wetland map viewer delineating wetland types and state jurisdiction.

The State of Delaware has the authority to regulate activities in tidal wetlands.  Regulated wetlands are maintained at the Federal, state and county levels. These regulatory maps can help determine if there are State of Delaware regulated tidal wetlands on a property. If a landowner wants to know the location of State of Delaware jurisdictional features or believes the map to be incorrect, a Jurisdictional Determination and Map Change Request can be made.

  1. State of Delaware Regulated Tidal Wetland Maps

What’s the difference between a wetland delineation and a map?

Wetland delineation

A wetland delineation is a legal determination of a wetland boundary. An environmental consultant is hired to go onto a property and thoroughly document the existence of water, species of plants, and soil conditions to determine if a wetland is present and then flag its outer boundaries. These delineations can be used to see if a wetland permit is needed.

Wetland map

A wetland map is created through a computer analysis of environmental data and aerial images, and is followed up with on the ground verification of a select number of field sites.  In the State of Delaware, every mapped location of wetlands has not been verified on the ground so these maps are only used for guidance purposes.

DNREC Sub-aqueous Lands LeaseThe property has wetlands, now what?

Don’t run away screaming!  Just because there are wetlands on a property, does not mean that the whole thing is unusable. Everyone wants a piece of land with a view, and wetlands can offer just that. Properties with wetlands are a wildlife watchers dream, have a built-in, no cost water purification system, offer drought protection, and can help reduce storm damage. Research has also supported the idea that healthy wetlands are good for maintaining underground water supplies (McCauley, 2015) which in turn can support crop growth on agricultural lands.

Wetlands are a prized natural resource. The best thing to do is to leave them alone, and give the wetland room to do its job. However if invasive plants, such as Phragmites australis, are a problem, some management of the plant maybe be beneficial to the health of the wetland and the property owner’s goals for the location.

You want to build where?

Keep in mind, you don’t want to build on wetlands.  Building on higher and dryer land will save you time and money in the long run. But if you have no other option, any activity that is planned on or near a wetland will most likely require a wetland delineation, mitigation plans that explain how wetland impacts have been minimized or are unavoidable, and permits or prior authorization at the Federal, state or county level.

Examples of activities that require permitting include filling of wetlands, removal of the buffer around wetlands, site access through a wetland, removing plants or tree stumps in a wetland or any sort of digging, construction or ditching in a wetland or stream.  Basically, any action you do that alters the landscape of a wetland or stream needs a permit or authorization from at least one governmental agency.

Resources on wetland permitting and regulations:

In Summary

Think of wetland maps and regulations as tools to help clients invest in the best locations to build on a property with high and dry land and ensure their investment can stand the test of time.  Thanks for your interest in Delaware’s wetlands! If you are interested in learning even more, visit

Handy Printable Delaware Resources:

A Guidebook for Public Decision Making in Wetland Decision Making & Permitting

Discovering Wetlands: A helpful guide for determining wetlands in your backyard


Mccauley, L. A., Anteau, M. J., Burg, M. P., & Wiltermuth, M. T. (2015). Land use and wetland drainage affect water levels and dynamics of remaining wetlands. Ecosphere,6(6). doi:10.1890/es14-00494.1

Tags: , , , , , , , ,


Now reintroducing….the Appoquinimink River watershed wetlands!

Written on: February 21st, 2019 in Wetland Assessments

The Appoquinimink River watershed is highlighted in dark purple.

The Appoquinimink River watershed is highlighted in dark purple.

by Erin Dorset, DNREC Wetland Monitoring & Assessment Program

Back in 2016, you were introduced to Delaware’s Appoquinimink River watershed and the types of stressors that we were looking for in our wetland health assessments. At that point, we had recently wrapped up our field work in that watershed, but we hadn’t yet completed any data analysis. We promised to keep you updated within the next couple of years with the results of all that tough work….and here, we deliver!

How did the watershed do overall?

The final count of wetland sites that we assessed turned out to be 30 estuarine wetlands (salt or brackish marshes), 31 flats, 36 riverine wetlands, and 27 depressions. With all four of those wetland types combined, the Appoquinimink River watershed’s wetlands were in fair condition—better than some watersheds, but worse than others.

Most of its wetlands were considered moderately stressed (49%), but quite a few were categorized as minimally stressed (34%), with the smallest proportion being severely stressed (17%). This meant that the wetlands in this watershed received a final overall letter grade of C+.

The Appoquinimink River watershed as it compares to the overall condition of 8 other previously assessed watersheds in Delaware.

The Appoquinimink River watershed’s wetlands as they compare to the overall condition of 8 other previously assessed watersheds in Delaware. Each bar represents the percentage of minimally, moderately, and severely stressed wetlands in each Delaware watershed.

What about the health of our different wetland types?

Estuarine wetlands

A dense stand of invasive common reed (Phragmites australis) in an estuarine wetland

A dense stand of invasive common reed (Phragmites australis) in an estuarine wetland

Breaking it down by wetland type, estuarine wetlands received the lowest letter grade of C. Their hydrology was in excellent condition, meaning that the water moved the way it should over the land. They remarkably lacked ditches, which are common in Delaware’s salt and brackish marshes.

However, their buffers (the land area around the wetland) contained some disturbances, and often lacked continuous forests or natural areas. These buffer stressors could introduce polluted water runoff into wetlands or decrease the amount of important wildlife habitat available to migrating animals.

Habitat refers to the status and condition of the plant communities and any roads within the wetland, and in this watershed it was in very poor condition. This is largely because of invasive plants, low marsh stability, and low vegetation thickness, all of which could be signs of marsh decline.

Non-tidal wetlands

Non-tidal freshwater wetlands (flat, riverine, depression) were a bit of a different story. They were in better overall condition than estuarine wetlands: Flats received a B-, riverine wetlands, a B, and depressions, a B.

Ditching through a flat wetland in the Appoquinimink watershed.

Ditching through a flat wetland in the Appoquinimink watershed.

Habitat and hydrology were in great condition overall for these non-tidal wetlands! Unfortunately, invasive plants were still detected in some wetlands, and ditching was present in some flats and depressions. Invasive plants can rapidly spread and displace native species, while ditching often reduces the water levels in wetlands creating an area that is not survivable for many animals and plants.

However, the main issues for all three of these freshwater wetland types were buffer stressors (problems in the land area around the wetland), as all of these wetlands scored very poorly for their buffers. Common buffer stressors for these wetland types included development, roads, and agriculture in the landscapes. These problems could increase unintentional impacts to non-tidal wetlands, such as polluted water runoff or reduced nearby wildlife habitat.

How has wetland acreage changed in the watershed?

We estimated that approximately 1,972 acres of wetlands have been lost in the Appoquinimink River watershed in the time period from the early 1700’s (human settlement of the area) to 2007. These wetlands were lost mostly because of human impacts such as residential and commercial development, roads, and agriculture. That’s a lot of wetlands!

The watershed has actually gained some wetlands in recent years too (290 acres from 1992 to 2007), but nearly all of the gained acreage is from the creation of ponds that are associated with development, roads, or golf courses. Such unnatural wetlands often lack plants and do not function as well as natural wetlands, so they by no means replace natural wetlands.

Additionally, some estuarine marshes along the coast of the Delaware Bay have become submerged and lost under water because of rising sea levels.

What can I do to help Appoquinimink wetlands?

A beautiful water-filled depression wetland in the Appoquinimink River watershed.

A beautiful water-filled depression wetland in the Appoquinimink River watershed.

Fortunately, now that we have assessed wetlands in the Appoquinimink River watershed, we know what the significant threats are. This allows us to come up with solutions, and we need your help to accomplish them! Here are some ways you can help:

To find out if you live in the Appoquinimink River watershed, visit Find Your Watershed Address. And, to see if you have wetlands on your property and more ways that you can help, visit the Freshwater Wetland Toolbox.

Where can I read the full Appoquinimink River watershed report?

The full scientific report and the shorter, reader-friendly report card for the Appoquinimink River watershed are both in their final editing stages, and will soon be publicly available on the WMAP wetland health website! There, you can also view and download reports and report cards from all other watersheds that have been assessed and analyzed to date.  Data for the tidal and non-tidal assessments can also be found on the Delaware Open Data Portal.

For questions about this report please contact

Tags: , , , , , , ,