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  Archived Posts From: 2019


Sassafras Landing: A living shoreline demonstration

Written on: September 16th, 2019 in Living Shorelines

Guest writer: Chris Pfeifer – Senior Principal, Cardno

Volunteers receiving instructions on how to plant in a living shoreline.
Volunteers receiving instructions on how to plant in a living shoreline.

On a warm July morning not long after the official start of summer, some 2 dozen volunteers gathered at Sassafras Landing, an unimproved boat launch popular with kayakers and duck hunters inside the Delaware Division of Fish and Wildlife’s Assawoman Wildlife Area (AWA) near Frankford. Their mission: transplant nearly 5,200 plugs of native marsh grass onto what otherwise appeared to be a pristine white sand beach. The efforts that day were the final phase in constructing a living shoreline, and the culmination of more than a year’s worth of planning and design by a multidisciplinary team of scientists and engineers from the Delaware Department of Natural Resources and Environmental Control (DNREC), the Delaware Center for the Inland Bays, and Cardno, a local consulting firm.

The problem

Nearly a year before, members of the design team waded along this very shoreline. What they encountered, unfortunately, was all too common in Delaware’s Inland Bays. Along most of the shoreline, ragged undercut banks choked with Phragmites were all that remained of the fringing salt marsh that once occupied the transition zone where land meets water.

Over time, most of the Spartina alterniflora, the dominant plant species of Delaware intertidal salt marshes, had been whittled away by erosion. Analysis of aerial photos confirmed the loss of about 11 feet of fringe marsh from this shoreline between 1992 and 2017. That’s about a ½ foot per year on average. It may not sound like a lot, but inches add up over time.

Salt marshes play an important role in combating shoreline erosion and protecting adjoining uplands. The leaves and stems of marsh grasses absorb and dissipate wave energy, while the dense, intertwining roots help bind the soil. Although marsh loss due to erosion is never a good thing, wider marshes can withstand the damage without sacrificing too much of their protective function. But narrower marshes, like at Sassafras Landing, are less able to sustain the loss. And in some places, the stakes are higher than others.

Such is the case at Sassafras Landing where the ever-narrowing marsh fringe helps protect and maintain an important feature just landward of water’s edge: a low berm of mounded soil constructed decades ago to separate the tidal waters of Miller Creek from 35 Acre Pond, one of five non-tidal freshwater impoundments within AWA managed for wildlife and ecological diversity. In the narrowest part of the berm, hastily piled rocks line an indentation in the shoreline; a stop-gap to repair erosion from a coastal storm that almost breached the berm several years ago and an ever-present reminder of the ongoing threat from shoreline erosion.

Aerial view of site during construction of the living shoreline.
Aerial view of site during construction of the living shoreline. Note the small area that separated the tidal water body from the non-tidal freshwater impoundment.

The solution

It was clear to the team that something was needed to address the shoreline erosion, but what? As a partner in a statewide initiative to increase awareness of alternatives to traditional “hard armoring” practices like riprap and bulkhead, the Delaware Center for the Inland Bays selected Sassafras Landing as a living shoreline demonstration project.

The term “living shoreline” refers to a suite of shoreline stabilization and erosion control techniques that use natural materials like wetland plants, oyster shells, and coconut fiber “biologs” to repair damaged shorelines and increase their resiliency to the adverse effects of erosion and sea level rise. Sometimes more structural components like rock are used in combination in what’s known as an “armored living shoreline.” Regardless of these variations, all living shorelines seek to sustain, enhance or restore ecological functions and maintain or reestablish connections between uplands and aquatic habitats across their natural gradients.

After evaluating several different living shoreline techniques in relation to site conditions and project goals, the design team selected an armored living shoreline treatment known as a rock toe sill. This treatment consists of a linear arrangement of free-standing rocks (the “sill”) just offshore parallel to the eroding shoreline. The area between the toe sill and the shoreline is then backfilled with clean sand, graded to appropriate elevations, and planted with native vegetation to create or restore a protective marsh fringe.

The 5-foot gap in between the rock sill during construction.

Information about parameters like shoreline orientation, topography, fetch, tides, wave energy, and water depths were gathered through a site evaluation process and then used to refine the conceptual design. After several iterations, the design was finalized. It included 5 segments of low-profile rock toe sill spanning just over 400 linear feet. Taking sea level rise into consideration, each sill is between 7-8 feet wide at its base and 2-3 feet tall, putting the top of each sill 6 inches above the average water level at high tide. Since only the highest high tides will overtop the sill, 5-foot gaps were included between each segment to allow for tidal exchange and passage of aquatic organisms. The western ends of all but one sill flare outward to shield the gaps from exposure to the northeast, the direction of the most powerful storm-driven wind and waves, and the longest fetch. As added protection, mesh bags containing oyster shells line the inside of each opening to help absorb wave energy and retain fill.

Once the design was finalized, permit applications were submitted to DNREC’s Wetlands and Subaqueous Lands Section and the U.S. Army Corps of Engineers. Due to the amount of fill required, the project did not qualify for DNREC’s Statewide Activity Approval for living shorelines, and instead received an individual subaqueous lands permit. Authorization from the Army Corps was granted under Nationwide Permit 27 for Aquatic Habitat Restoration, Enhancement, and Establishment Activities.

Funding for project construction was received through the 319 Nonpoint Source Program Grant and in-kind contributions from several of the groups involved. Construction of the toe sill, backfilling, and grading were all performed in-house by the Division of Fish & Wildlife’s Little Creek construction crew. Staff from AWA, Cardno, and Delaware Center for the Inland Bays oversaw the construction activities.

Breaking ground

Earthwork was initiated in early June and was completed over the next four weeks. Which brings us back to where we started. As the final step, nearly 5,200 plugs of three different species were planted in zones according to their hydrologic preference. Spartina alterniflora, known commonly as smooth cordgrass, was planted at the lowest elevation. Spartina patens (saltmarsh hay) followed higher on the shoreline, above the level of daily tidal inundation. Switchgrass (Panicum virgatum) was mixed in at the highest elevation where the new shoreline meets the berm.

Just two short months after completion, the Sassafras Landing living shoreline is indeed coming alive. Aside from a few dead or missing plugs, which is to be expected, the planted grasses are thriving. Although individual plugs are still recognizable up close, even from a short distance away, the shoreline is beginning to take on a more and more natural appearance.

Schools of small fish abound in the quiescent water landward of the sill along with a handful of blue crabs. Though the new living shoreline has yet to be tested by tropical storm or nor’easter, we remain ever hopeful that the efforts of this spring and summer, and the planning and design that preceded construction, are the beginning of a new chapter for this little piece of shoreline and the valuable habitat it protects.

The completed Sasafrass living shoreline project after Hurricane Dorian passed in August of 2019.

The completed Sassafras Landing living shoreline project after Hurricane Dorian passed and brought high water levels in August of 2019.

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Piedmont vs. Coastal Plain Wetlands: A tale of two regions

Written on: September 16th, 2019 in Outreach

by Erin Dorset & Kenny Smith, DNREC Wetlands Monitoring & Assessment Program

If you spend a lot of time traveling around Delaware, you’ll notice that northern Delaware is very different from the rest of the state. That’s because Delaware is made up of two distinct geologic regions. The northernmost part of Delaware is within the Piedmont region, while the rest of Delaware lies within the Coastal Plain region.

The Coastal Plain is relatively flat and is characterized by small hills, gradual slopes, and sandy or silty stream beds. In contrast, the Piedmont region tends to have bigger rolling hills, steeper slopes, some small cliffs, and stream beds with more rocks, much like a lot of Pennsylvania.

What does this have to do with wetlands, you ask?

Flat wetlands

Landscape characteristics play a big role in determining what kinds of wetlands occur in different areas. So, there tend to be differences in the wetlands in the Piedmont and Coastal Plain regions. Through our years as wetland scientists, doing fieldwork all over Delaware, we have made some first-hand observations about wetlands in these two geologic regions. For example, we have seen that flat wetlands are one of Delaware’s most common wetland types in the Coastal Plain, yet they are fairly uncommon and often smaller in size in the Piedmont because of more varied terrain.

Riverine wetlands

Another observation that we’ve made is that riverine wetlands are often larger in the Coastal Plain. Streams and rivers in that region typically have gradual banks, allowing water to easily overflow into floodplain areas. In contrast, riverine wetlands that we’ve seen in the Piedmont region are often smaller, and many waterways do not have any riverine wetlands along them at all. This is because stream banks tend to be higher and steeper, and streams are often found at the bottoms of slopes, so flood waters do not cover as much land when the banks overflow. The slope of the land also tends to drain water off more quickly, so floodplain areas may not stay wet for as long.

Beautiful riverine wetlands in the northern Piedmont region (left) and central Coastal Plain region (right) of Delaware. Notice the rocky bottom and sharp slopes in the image on the left, and the river banks with very gradual slops in the image on the right.

Seepage wetlands

A closed-canopy seepage wetland in northern Delaware.
A closed-canopy seepage wetland in northern Delaware.

Yet another thing that we have noticed is that seepage wetlands are more common in the Piedmont region than in the Coastal Plain. Seepage wetlands are wetlands formed in places where groundwater comes out onto the surface year-round or nearly year-round. Some of them are closed-canopy seeps, meaning that they are within the forest and create the headwaters of some streams. They are usually dominated by skunk cabbage and are small and narrow in size and shape. Others are open-canopy seeps, which are wet meadows fed by closed-canopy seeps. These have few trees and shrubs and a wide variety of herbaceous plants. Seepage wetlands tend to form at the bases of slopes, which is why they are prevalent in the Piedmont region and are not as common in the Coastal Plain.

Check them out!

Curious about making some of your own observations? Check out some of these parks and forests that will let you compare and contrast the Piedmont and Coastal Plain regions of Delaware!

Piedmont region

Coastal Plain region

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Confessions of Seasonal: Everlasting impressions

Written on: September 16th, 2019 in Wetland Assessments

Samantha Stetzar, seasonal with the Wetland Monitoring Assessment Program

by Samantha Stetzar, University of Delaware Student

Working in wetlands

Wetlands work is not for the faint of heart. I won’t sugar coat it for you. Its dirty. Its messy. Oftentimes pretty buggy (even though we really lucked out this year). Yep. Wetlands can be all of those things. But – they are also so much more. I don’t think I’ve learned so much in one summer than I did working as a seasonal with DNREC’s Wetland Monitoring & Assessment team.

This year we focused primarily on wetlands in the Brandywine Watershed, or rather, the Piedmont region of Delaware. Since this watershed was so unique in that it contained elevation, topographical configuration allowing for seep wetlands to emerge, I got a closer look into how the protocol is adapted and modified. Due to the unique topography of the region, assessing these wetlands became more of a challenge in comparison to previous watersheds in relatively flat locations of Delaware. However, I welcomed the challenges!

Each and every site was a new adventure, whether it be trudging through an abandoned town – turned mitigation site to discover the most strangest depressions, or practically clawing our way up cliff-sides I never would have imagined existed in Delaware, and even trekking across a railroad bridge suspended 30 ft above a shallow creek . No matter what obstacle stood in our way, I was eager and ready. Through the whole summer I truly felt like a contributing member to part of a team working towards a goal much larger than ourselves.

As summer comes to an end

I find myself stuck in permanent wetlands detective mode, constantly surveying the landscape for indicators of wetlands

I didn’t realize until a week out of the job just how much of a profound impact this position had on my outlook on life. I’ve become more positive, patient and resilient. Not to mention the amount of knowledge I’ve learned from the many experiences and my amazing team members. By the end of the summer I find myself stuck in permanent “wetlands detective mode”, constantly surveying the landscape for indicators of wetlands and quietly naming off species within the local plant communities (thanks for the help with scientific names!). But this has something to say about DNREC’s wetlands team and phenomenal monitoring and assessment program.

This position was as much as a learning experience as it was a job; and I’ve left with so much more than when I started. I only hope more people will have an opportunity to realize the amount time and hard work wetland scientists dedicate to protecting Earth’s remaining wild spaces.

It’s important that we continue to assess and monitor the remaining wetlands that we have in order to ensure their existence for future generations to come. So I urge you, if you ever do get a chance to go out with a wetlands scientist, dive right in, no questions asked – just make sure you have hip-waders on first! Not only will you return with a myriad of knowledge and a renewed sense of appreciation for the natural world, but the satisfaction of a hard day’s work. So get ready. It’s time to get comfortable with being uncomfortable!

But – I won’t leave you with just that…here’s some fun facts I learned working in the Brandywine Watershed with DNREC’s WMAP team:

View overlooking the rolling hills in Delaware's Piedmont region.
View overlooking the rolling hills in Delaware’s Piedmont region.
  1. Delaware does have some crazy elevation. Yes, you are reading that right. The state Delaware and elevation are in the same sentence! Believe me. We’ve climbed up most of them.
  2. Wetlands can be identified by the stuff we find in them. Yes. 99.9% of wetlands will contain at least 1 golf ball. We have proof. Typically we categorize a wetland by soils, plant community and hydrology. I’m thinking golf ball should be #4.
  3. If you are out working with Alison, its likely you’ll stop for ice cream. Like 95% of the time. Which is amazing…unless your lactose-intolerant!
  4. Some people manage to emerge from fieldwork unscathed (Kenny), but if you’re like me, you claw your way out of the last site resembling something closer to the creature from the black lagoon
  5. Finally, wetlands work is not for the faint of heart, but if you can get past the smells, stings and thorns, you’ll find some of the most rewarding work + people out there!

This post is part of a series of posts titled “Confessions of a Seasonal”, and is written by a summer seasonal worker of DNREC’s Wetland Monitoring & Assessment Program.

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Pole Replacement Spawns Marsh Recovery Data

Written on: September 6th, 2019 in Wetland Assessments

Guest writer: Christina Whiteman, DNREC’s Delaware National Estuarine Research Reserve

When a power company needed to replace a utility pole in a saltmarsh, staff at the Delaware National Estuarine Research Reserve (DNERR) jumped at the opportunity to work closely with the power company and other state agencies to study how the marsh would recover naturally from this man-made disturbance.

But first, a little pregame

DNERR interns monitoring vegetation height and density.
DNERR interns monitoring vegetation height and density.

The DNERR is one of 29 reserves across the country and was established in 1993 as a cooperative program between Delaware’s Department of Natural Resources and Environmental Control (DNREC) and the National Oceanic and Atmospheric Administration. It is comprised of two components: the Blackbird Creek Reserve in Townsend and the St. Jones Reserve in Dover. The Reserves are also used as reference sites, habitats that are unaltered or close to their natural state, by DNERR and other organizations to study the impacts of climate change.

At the DNERR, the Research and Stewardship programs work together to understand how the marsh changes over time through long-term wetland vegetation monitoring (i.e. we get nerdy with some plants and mud). One of the reference sites in the DNERR Biological Vegetation Monitoring Program, is at the St. Jones Reserve along the St. Jones River. The vegetation monitoring that takes place here is part of a nationwide effort within the National Estuarine Research Reserve System, where numerous long-term datasets are collected on water quality, wetland plants and surface elevation tables.

A scientist and an engineer walk into a bar

Leaning power pole
Leaning power pole.

In 2013, DNERR was notified that there was an emergency pole replacement project that needed to be implemented to prevent a leaning power line from collapsing, but the proposed project went through the DNERR Biological Vegetation Monitoring Program site. In order to ensure that the power lines were replaced in a way that would prevent long-term datasets from becoming compromised, DNREC and the power line company went to work.

The collaboration resulted in an installation method that would reduce harm to the marsh, while also maintaining the integrity of the long-term datasets. In 2015, the power lines were replaced using a helicopter to install the poles at each location, instead of using heavy machinery across the marsh. To help the construction workers get around, an airboat and amphibious tracked vehicle were used to transport them to each pole.

One of the interesting outcomes from the planning process was that the emergency pole replacement project presented a unique opportunity for the DNERR to study resiliency of wetland ecosystems to low impact construction within a closely monitored area.


After the project was completed, the DNERR was interested in understanding how wetlands naturally recover over time without human interference. Since the DNERR has an established protocol for monitoring wetland plants, this protocol was used to begin a monitoring project in the construction area.

Clapper rail tracks on a mudflat in the construction area.
Clapper rail tracks on a mudflat in the construction area.

Photo documentation was added to the monitoring protocol to visually understand how landscapes change or recover. Some areas of the power line replacement monitoring project have changed to provide new habitats that didn’t exist before. For example, in areas that were heavily trafficked during the construction efforts, mudflats with dense wetland plants on the edges have created foraging habitat for marsh birds.

Another thing we learned is that areas where the wetland plants have recovered did not have many small streams or channels. Other areas that changed and have not recovered as quickly all had significant water flow in the construction areas.

Lesson learned: if there is a need for construction in the future, it might be a good idea to avoid or maneuver around streams or channels to minimize impacts to the wetland.

Site post construction in 2015 (left) and 2019 (right). Notice the water paths have remained over the years.
Site post construction in 2015 (left) and 2019 (right). Notice the water flow paths have remained over the years.

Looking forward

Although the DNERR has been monitoring this area for four years, there is still a lot of information that can be collected to understand how the marsh naturally recovers over time. It will be interesting to see how this area looks in the future, and that’s one of the fun parts about science! 

For more information about this project, please contact

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Wetlands are Magicians of Water Quality Improvement

Written on: May 15th, 2019 in Outreach

by Alison Rogerson, Wetland Monitoring and Assessment Program

In our Wetland Monitoring and Assessment Program we speak so often about the ecosystem services that wetlands provide or the beneficial functions wetlands perform daily.  We rattle them off in varying order “provide vital habitat for plants and wildlife, improve water quality, protect our coasts, act like a sponge to store floodwater, sequester Carbon from the atmosphere”.

We do this so often, that sometimes we forget to take a step back and explain what exactly we mean and how exactly wetlands work. For example, how can a wetland clean water?? Wetlands are muddy and sometimes stinky. How on earth could a wetland clean my water?

The Magical Act

Wetlands are magicians. In their own, natural, wonderful form, they magically filter out and pull aside an assortment of nasty stuff that you and I don’t want in our streams, bay and ocean, or as we kayak and fish.

What can wetlands help filter out from our waters, you might ask?

How wetlands work. Public Employees for Environmental Responsibility.

How wetlands work. Public Employees for Environmental Responsibility.

  • Pesticides running off of lawns and farm fields, excess nutrients such as Nitrogen and Phosphorus that cause harmful algal blooms and fish kills
  • Toxic chemicals that run off of our streets and industrial areas
  • Excess sediments that wash off of construction areas after a heavy rain
  • Even normal organic material that could clog waterways

A Look Behind the Curtain

A magician rarely reveals their secrets, but in this case we’re spilling the beans.  Wetlands remove nutrients through a combination of complex physical and biological processes. Let’s break it down (pun intended)..

Physical processes

Wetlands are like sponges and are great areas for holding onto water. They are also areas where the speed of water flow is drastically reduced and sometimes even stands still. As the water sits in the wetland, nutrients can be removed from the water in a couple of ways: they can simply sink down and settle on the soil surface, be released into the atmosphere or be trapped in the soil as the water filters its way slowly down through the ground.

As you can see, soils play an important role in this physical process.  One of our favorite marsh metaphors to use in presentations is that wetland soils are like a strainer or sieve. We hold up a pasta strainer and kids look at us like we’re crazy but really, it fits. Just like the strainer, wetland soils have lots of tiny holes, nooks and crannies (think English muffin) to trap impurities and toxins.  This process allows the cleaner water to continue on through, entering the stream or bay or even our underground aquifers.

A simplified illustration of the nitrogen and phosphorus cycles in a wetland (modified from Kadlec and Knight (1996), “Treatment Wetlands”; images from IAN, University of Maryland).

A simplified illustration of the nitrogen and phosphorus cycles in a wetland (modified from Kadlec and Knight (1996), “Treatment Wetlands”; images from IAN, University of Maryland).

Biological processes

There are also biological processes occurring in wetlands that can help to clean our waters.  Plants, algae, and bacteria can use and transform nutrients that have sunk onto and in the soil to grow big and strong and create future generations.

Bacteria (or microbes) are really neat organisms that do some fancy biogeochemical processes called nutrient transformations. Ammonification, nitrification and denitrification are examples of nutrient transformations that turn not-so-great chemicals into less harmful ones or into a useful nutrient for plants.  All of these processes are facilitated in many places throughout a wetland.

Healthy microbes also need a good source of carbon for their growth and energy and wetland plants serve as a key source of carbon! So the take home message is that these bacteria rely on wetland plants, and a wetland planted with lots of native plants (as opposed to an open pond) is going to be capable of the most nutrient transformation.

Coming Soon to a Theatre Near You

If you’re thinking that this is interesting but doesn’t affect me, you might be surprised to learn that approximately 25% of the State of Delaware is made up of wetlands, and that from where you are reading this right now, there is probably a wetland within a mile of you.  This means that a wetland is hard at work for you right now trying to keep up with all the demands we place on them.

There are a few things you can do to lighten their load, so to speak.

  • Provide ample vegetated buffers around wetlands. Buffer requirements in Delaware are not generous so it’s up to the practitioner or landowner to help wetlands help you.
  • Avoid draining or digging up wetlands. Sometimes harmful substances are kept and stored buried deep down within wetland soil. They key to this is to leave them there. When a wetland is drained or dug up and disturbed those locked up nasties are released. This included atmospheric carbon which we haven’t even talked about yet. Thus, another reason to protect natural wetlands.
  • Lastly, do your best to avoid impacting them, so you don’t have to take on the costly measure to  restore or replace them.

Let the magician put on a show uninterrupted and we can all enjoy cleaner, healthier waters!

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Delaware’s Freshwater Mussels

Written on: May 14th, 2019 in Wetland Animals

Guest writer: Clare Sevcik, DNREC’s Nonpoint Source Program

There are so many charismatic animals that make Delaware waterways their home. Most people living in Delaware can easily recognize a few of the most popular species: bald eagles, osprey, blue crabs, horseshoe crabs, beavers, river otters, and many more. But there are many more animals living below the water’s surface that are incredibly important to the area’s ecology. One of these lesser known animals are the freshwater mussels.

Mussel habitat in the Blackbird Forest

Mussel habitat in the Blackbird Forest

Where do they live?

Freshwater mussels are bivalve mollusks that live along the bottom of rivers, streams, and lakes in softer substrates like sand. They can live for a very long time and, in a healthy environment, some species can live to be 100 years old!

North America is also home to the most species of freshwater mussels in the world. Around 300 species live here. Worldwide, there are about 1,000 species. So, we are home to almost 1/3 of the world’s species. Most of those are found east of the Mississippi River, too.

The life cycle

Freshwater mussels have an unusual life cycle. Before they settle and become the slow-moving bottom dwellers we all picture, they are very mobile and hitch rides on the gills of various fish. For the first portion of their lives, they’re parasites.

Female mussels internally fertilize their eggs with the sperm of nearby males. Once fertilized, she releases the larvae (called glochidia) as migrating fish pass by. The glochidia are attached to the fish’s gills until they are large enough to survive on the stream bottom, which may be far away from their parents since fish can travel great distances and against currents. Mussels depend on these fish and each mussel species relies on different fish species to host their young.

Adult freshwater mussels (Partnership for the Delaware Estuary)

Adult freshwater mussels (Partnership for the Delaware Estuary)

Can I eat them?

Interestingly, freshwater mussels aren’t eaten by humans, like their saltwater relatives. Native Americans used to supplement their diets with mussels, but nowadays we have many more protein options. Freshwater mussels aren’t as tasty as their saltwater counterparts and can often be full of pollutants and/or parasites that have bioaccumulated over their lifetime of filter feeding.

Most species are also classified as endangered or threatened and cannot be collected. Instead, they are eaten by raccoons, muskrats, river otters, fish, and turtles. But they serve a much more important ecological function than just being food.

What do they do all day?

Mussels are incredibly efficient water filters! A single mussel can filter through approximately 20 gallons of water per day. Why do they filter so much water? Mussels are filter feeders and comb the water for food, such as algae, bacteria, and small, microscopic plankton. While doing so, they reduce the amount of sediment and other nutrients in the water.

Even though they are such productive water filters, freshwater mussels are very sensitive to the quality of their environment. They cannot survive in waters that are heavily polluted or in areas with erosion and sedimentation issues. Thus, mussels are more likely to be found in cleaner waterways that are not overwhelmed by pollution, runoff, or erosion.

Their sensitivity to water quality also makes them great bioindicator species, as they can only survive in healthier waters. A bioindicator species can tell researchers how healthy a waterway is based on their presence or absence.

How are they doing?

Due to many factors, freshwater mussel populations have been declining, and approximately 70-80% of North American species are considered endangered. They are threatened by poor water quality and reduced access to their fish hosts. Dams prevent fish from traveling upstream, so some mussel populations have been effectively cut off since without hosts young mussels wouldn’t be able to survive in the water column.

But even if their hosts are available, the areas suitable for mussel survival are scarce. So once they detach from the host’s gills, they can’t survive in those areas. Mussels have also been affected by invasive species, such as zebra mussels and Asian clams. These invasives tend to reproduce quickly and overpower local mussel populations.

What’s being done about freshwater mussels and their decline?

A LOT! Various nonprofit organizations and state agencies, such as our program within DNREC, have been actively trying to monitor mussel populations and improve local water quality.

The Partnership for the Delaware Estuary (PDE) has an extensive program in place to try to monitor and restore native mussel populations to the Delaware River, Susquehanna River, and their tributaries. PDE plans to open a freshwater mussel hatchery in southwest Philadelphia in 2023. The hatchery aims to produce 500,000 mussels per year to reestablish populations.

Additionally, dams in Delaware are slowly being removed and allowing fish to freely migrate through waterways, which will reconnect isolated populations and introduce glochidia to new areas.

Even with all of those programs and actions in place, native freshwater mussel populations will take a long time to recover, especially species that grow slowly. So we have to try to expedite their recovery by improving water quality as soon as possible!

What can I do to help?

There are many things you can do, regardless of where you live, to improve local water quality. Reducing fertilizer use, installing rain gardens and buffers, and even picking up trash can help reduce water pollution. For more information on how you can help improve local water quality, check out the Delaware Watersheds and Livable Lawns websites!


Wetland Monitoring and Assessment Program: Celebrating 20 years

Written on: May 14th, 2019 in Wetland Assessments

by Alison Rogerson, Wetland Monitoring & Assessment Program

Our Roots

Amy Jacobs and Chris Bason examining hydric soils in 2004.

Amy Jacobs and Chris Bason examining hydric soils in 2004.

In 1998 the Delaware Department of Natural Resources and Environmental Control’s (DNREC) Environmental Scientist, Amy Jacobs (now with The Nature Conservancy), took part in a grant project held by the Delaware chapter of The Nature Conservancy and the Smithsonian Environmental Research Center. This project developed the science and comprehensive hydrogeomorphic models for freshwater wetlands in the Nanticoke River watershed and assessed water quality benefits of wetlands in varying condition.  This was done to develop a wetland profile for wetlands in that watershed.

Then, in 1999 DNREC addressed the need to track not only the acreage of wetlands across Delaware and how that acreage is changing over time, but also examine the on-the-ground condition of wetlands. Measuring wetland condition compared to reference condition (the best and healthiest wetland you can find) gives a measure of how well wetlands are able to perform their natural functions and benefits.

Are our wetlands capable of trapping carbon, of intercepting and filtering pollutants from our surface waters, of holding stormwater and preventing flooding? These free benefits were underappreciated and not well tracked. If we can rate and track wetland condition as it relates to wetland function, we can grasp where wetlands are thriving and where they need work. Thus began the mission of the Wetland Monitoring and Assessment Program (WMAP)!

Statewide wetland condition assessment schedule by watershed.

Statewide wetland condition assessment schedule by watershed.

Let it Grow

Since then we have been building and growing! Our program has (with some partner collaboration) created 4 standardized wetland assessment protocols that rate wetland health, function and features. Working watershed by watershed we have visited nearly every corner of Delaware on the ground (12 watersheds).

This summer we will be working in the Brandywine Creek watershed which leaves only the small Pocomoke River still to visit. Over that time we have visited and assessed 1,420 random wetland sites across the state. With the help of willing landowners we have been able to access public and privately owned wetlands, allowing us to accurately rate wetland health statewide.

Former seasonal hires Megan Furman and Matt King completing an assessment in a tidal wetland in 2012.

Former seasonal hires Megan Furman and Matt King completing an assessment in a tidal wetland in 2012.

Along the way we met and worked with roughly 20 young professionals who joined us as seasonal wetland field technicians, assisting us during the busy summer season. Fieldwork is an adventure for everyone involved and we enjoy making memories and sharing our passion for wetland science with young minds.

It is so exciting the see how the Wetland Monitoring and Assessment Program has grown over the years. Growing out of a research study with The Nature Conservancy, Smithsonian Environmental Research Center, and Environmental Protection Agency, the program has held firm to using science as their foundation to improve management and educate a wide diversity of audiences. – Amy Jacobs, The Nature Conservancy, reflecting on where the program started two decades ago

From Paper to Practice

Because unused data is wasted data we try our best to share our work and our information with the widest audience possible through every means we can. Over 20 years we have amassed thousands of photos, thousands of points of data and the most comprehensive tidal and non-tidal wetland condition dataset in the Mid-Atlantic Region.

Kenny Smith leads a young girl through a clay impression craft using wetland plants at the University of Delaware Coast Day 2018 in Lewes.

Kenny Smith leads a young girl through a clay impression craft using wetland plants at the University of Delaware Coast Day 2018 in Lewes.

Reaching the general public

Over the years we have gotten better at communicating wetland science and findings to an audience that isn’t always wetlands savvy. We’ve asked, we’ve survey and we’ve listened to what is important to Delawareans and how we can inform them to improve wetland protection and conservation.

Our program has been extremely fortunate to receive funding that allows us to continually grow and develop our program, addressing new needs as they arise. In 2008 we added a team member to focus on outreach and education which enables us to share our projects and results with many audiences online and in-person. We continue to expand our audience every year and we now average 3,500 in-person interactions per year through presentations, workshops, and exhibiting at events.

Mike Polo films Alison Rogerson in a Wetland 101 video on salt marsh migration for the DNREC You Tube channel.

Mike Polo films Alison Rogerson in a Wetland 101 video on salt marsh migration for the DNREC You Tube channel.

As times change so have we to reach a wider audience. In 2011 we established a Delaware Wetlands Facebook page which has accrued 2,000 followers. In 2014 we started an Instagram account which now has 1,200 followers who get to enjoy pictures of our adventures and mishaps in the field. Additionally we decided to start making short educational videos, which are great for anyone teaching about wetlands. This really pushed us out of our comfort zone! We have now starred in 14 videos which have 44,000 views.

Reaching wetland professionals

Over the course of our program our staff has given approximately 275 professional presentations to audiences around the country (and internationally too!).

But we didn’t stop at attending and presenting at conferences. We decided to convene wetland professionals of all types from around the state and eventually around the region for a Delaware Wetlands Conference. Held for the first time in October 2001 at Cape Henlopen State Park, the agenda focused on wetland status in Delaware, wildlife and habitat management, monitoring, restoration and permitting.

Presentation during the 2018 Delaware Wetlands Conference.

Presentation during the 2018 Delaware Wetlands Conference.

Over the years the conference moved to the Dover Sheraton Hotel to the Dover Downs and now the Chase Center on the Riverfront in Wilmington. What started as a one-day gathering of 100 has expanded to a two-day event for 350.

With 8 conferences on the books we are still striving to make the conference worthwhile and effective. Although it requires a year of planning, hosting the Delaware Wetlands Conference is extremely rewarding. To see so many sectors of professionals gathered together with a common interest in wetlands and a desire to learn and collaborate is inspiring. We look forward to the 2020 conference already!

Looking to the Future

We’ve accomplished a lot for such a small program, but we still have a lot to do.  Another early member of the program Chris Bason, Executive Director for the Delaware Center for the Inland Bays gives the program kudos for its accomplishments but questions if the resulting scientific information is being heeded.

Wetland science in Delaware is very strong thanks in large part to the WMAP and the EPA’s and State’s continued investment in the Program… The question on the minds of those that have worked so hard to understand the importance and condition of these extraordinary natural resources remains: will Delaware’s political leadership be moved by the 20 years of science indicating these wetlands need protection? – Chris Bason, Delaware Center for the Inland Bays

Sunrise of a Leipsic River marsh.

Sunrise of a Leipsic River marsh.

For now we will focus on gathering relevant information and sharing our work with familiar and new audiences alike. For example, we are focusing on providing realtors and homebuyers with important information and tools to navigate buying and owning wetlands.

In addition, in 2019 we will be releasing 10-year updated statewide wetland maps and examining how and where wetland acres have changed in a decade.

Every year we continue to set higher goals for our program to reach a wider audience, interact with more citizens, tackle new issues, and push our limits in the name of wetland science and wetland conservation. Remember, you can find us on this blog, our social media accounts above, or main website anytime of day for wetland fun facts, photos, wetland research and data.  See you around!

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Birding in Delaware’s Wetlands

Written on: May 8th, 2019 in Wetland Animals

Atlantic Flyway (U.S. Fish and Wildlife Service)

Atlantic Flyway (U.S. Fish and Wildlife Service)

by Erin Dorset, Wetland Monitoring & Assessment Program

Birding is always exciting in Delaware. While some bird species are year-round residents, many others are migrants traveling along the Atlantic Flyway. This keeps things interesting, as it allows birders to see a very wide variety of species throughout the year. A lot of these awesome birds exist in or near wetlands in Delaware, which makes wetland habitats great places to go birding!

Where are the best places in Delaware to see birds in wetland habitats?

Here are some of the best sites to see birds in wetlands in Delaware (though this is not an all-inclusive list). For each place, we describe location, wetland habitat types, and how to get around. This will hopefully help you find the best locations that suite your birding interests!

Tidal marshes and mudflats at Bombay Hook National Wildlife Refuge

Tidal marshes and mudflats at Bombay Hook National Wildlife Refuge

Bombay Hook National Wildlife Refuge

Location: Smyrna

Wetland habitat types: tidal marshes, impoundments, mudflats

Description: This large refuge is probably the most well-known birding spot in the state. While there are some short walking trails and some observation towers at Bombay Hook, most of the refuge can be explored along a 12-mile driving loop. There are many places to pull off of the driving loop to look for birds in the wetlands.

Additional info: Click here to learn more about birding at Bombay Hook and see the map of the refuge. Also, view the refuge bird checklist for more details about what time of year you are likely to see different species.

Prime Hook National Wildlife Refuge

Location: Milton

Wetland habitat types: tidal marshes, impoundments, mudflats, forested wetlands

Description: Prime Hook is another large federal refuge that can be explored on walking trails, by driving, or by a canoe trail. It is the site of a large restoration project that was designed to rebuild degraded tidal wetlands, which means that birds should benefit from the project!

Additional info: Check out the refuge map. Also see the bird checklist for more details about what time of year you are likely to see different species.

Little Creek Wildlife Area

Location: Dover

Wetland habitat types: tidal marshes, impoundments, mudflats

Description: This is a state wildlife area that is made up of several tracts of land.

There are several parking lots and boat ramps, most of which require you to have a Conservation Access Pass (CAP). While there aren’t any designated walking trails, you can stop along roadsides, or view birds from a boat or a wildlife viewing tower. Note that hunting is permitted here.

Additional info: Check out the map of the wildlife area.

Gordons Pond at Cape Henlopen State Park

Gordons Pond at Cape Henlopen State Park

Cape Henlopen State Park

Location: Lewes

Wetland habitat types: tidal marshes, impoundments, mudflats, forested wetlands

Description: This state park has many hiking and walking/biking trails throughout many habitat types. Some go through maritime forest and dunes, and others pass by tidal marshes and a large impoundment (Gordons Pond). There is also a nature center at Cape Henlopen, where you can watch a live osprey camera! Plus, volunteers can participate in a hawk watch every spring and fall here.

Additional info: Look at the map of the state park, and check out the park’s birding checklist.

Blackbird State Forest

Location: Townsend

Wetland habitat types: forested wetlands

Description: Blackbird State Forest is quite large; it is made up of 9 tracts of land with about 40 miles of trails. This means there are great opportunities to find birds in and around the forest’s freshwater wetlands! Be aware that hunting is permitted within the forest.

Additional info: See the maps of the state forest tracts

Lums Pond State Park

Location: Bear

Wetland habitat types: forested wetlands

Description: The Swamp Forest trail goes around Lums Pond and through patches of forested wetlands for over 6 miles, providing a great opportunity to see birds that are associated with wooded wetlands! There are also several other trails and a nature center to enjoy.

Additional info: View the map of the state park

Piney Point tract of Assawoman Wildlife Area

Piney Point tract of Assawoman Wildlife Area

Assawoman Wildlife Area

Location: Frankford

Wetland habitat types: tidal marshes, mudflats, impoundments, forested wetlands

Description: This is a state wildlife area that is made up of several tracts of land.

It has several parking lots and boat ramps, most of which require you to have a Conservation Access Pass (CAP). While there aren’t any designated walking trails, you can stop along roadsides, or participate in the auto tour. You can also view birds from a boat or a wildlife viewing tower. Note that hunting is permitted here.

Additional info: See maps of the wildlife area tracts

To learn about some more great birding locations in Delaware, including places with non-wetland habitats, see the Delaware Birding Trail.

What birds might you see at these locations?

While these are not all-inclusive lists—and some birds may cross over from one habitat type to another– here are some of the bird species that you might encounter in different wetland habitats in Delaware.

American avocet (Cornell Lab of Ornithology)

American avocet (Cornell Lab of Ornithology)

Tidal marshes

Clapper rail; Virginia rail; Marsh wren; Seaside sparrow; Saltmarsh sparrow; Great blue heron; Snowy egret; Great egret; Willet; Least bittern; Northern harrier; Osprey; Common moorhen; Sora; Glossy ibis; Forster’s tern


Semipalmated sandpiper; Least sandpiper; Sanderling; Semipalmated plover; Greater yellowlegs; Lesser yellowlegs; Black-necked stilt; Ruddy turnstone; Dunlin; Short-billed dowitcher; Red knot; Willet

Impoundments, ponds, or pond edges

Mallard; Northern shoveler; Green-winged teal; Blue-winged teal; Northern pintail; Gadwall; Bufflehead; Canada goose; Tundra swan; Snow goose; American black duck; Ruddy duck; Black-crowned night heron; Yellow-crowned night heron; Green heron; Great blue heron; Common moorhen; Least bittern; Red-winged blackbird; American avocet

Cerulean warbler. Image credit: Cornell Lab of Ornithology

Cerulean warbler (Cornell Lab of Ornithology)

Forested wetlands

Wood duck; Cerulean warbler; Louisiana waterthrush; Warbling vireo; Yellow-throated vireo; Prothonotary warbler; Kentucky warbler; Yellow-throated warbler; Barred owl; Eastern screech owl; Great-horned owl; Wood thrush; Northern flicker; Downy woodpecker; Red-bellied woodpecker; American woodcock

Put on some boots, grab a field guide, get out those binoculars and start birding!  Want to contribute to bird conservation efforts? Submit your birding checklists to eBird today!


Wetlands are like sponges, how?

Written on: March 11th, 2019 in Outreach

by Brittany Haywood, DNREC Wetland Monitoring and Assessment Program

Wetlands Protect: Sponge graphicOne part of our job is going out into the public and explaining simply our research and the benefits of wetlands.  We often use the saying, “wetlands are like sponges” to describe their ability to absorb water, but recently we’ve been asked exactly how that is so.

Describing wetlands as sponges dates back all the way to 1784 where Nicholas Turner described peat wetlands as, “in the nature of a sponge; for if a dry piece is put in water it will absorb double its weight” (Turner, 1757 p40).  Since then this metaphor has been used all over the world to describe one of the many benefits that wetlands provide.

For this blog post we will explore the two linked concepts: one, how do sponges work, and two, how wetlands absorb water. Then, we will package it all up with a nice neat bow to make the connection that will hopefully satisfy all you knowledge seekers out there.

How do sponges work?

When you put a sponge in water, it absorbs it.  This happens because the bubble like spaces inside the sponge have the ability to hold water and the sponge material locks it in. Water won’t be released until someone forces it out through squeezing or it could be allowed to dry out over time.

spaces in sponges allow it to hold and trap waterAlso, have you ever noticed that it’s easier for a damp sponge to soak up water than a completely dry one?  That’s because water is extremely sticky, and it sticks better to itself than anything else.

Nerdly speaking, water is a molecule made up of two hydrogen atoms and one oxygen atom. These molecules really like to form hydrogen bonds with each other, i.e. water loves to stick to itself. This is called cohesion. Water will also stick to other objects, like the dry sponge or soil, but it doesn’t do it quite as well. This is called adhesion. (Exploring Our Fluid Earth, 2019)

How do wetlands absorb water?

Wetlands are made up of wet soils, water loving plants, and of course, water.  Soils have lots of spaces in between the soil particles called soil pores. And like the setup of the sponge, they can hold and trap water. How much water they hold onto depends on the pores sizes and soil type. Clay soils have small pores and trap water very well whereas sandy soils have larger pores allowing water to move more freely through it.  Also these mineral type soils tend to attract water because of their unsatisfied ionic charge.  (Nelson, 2015)

Pore Spaces in Soil

Pore spaces are in between the soil particles. The soil particles (soil material) trap the water. The two graphics represent two different soil types. (Nelson, 2015)

Wetland plants also play an important role in water absorption.  These plants are specifically adapted to live in watery places. They absorb water and use what’s in it to grow.  So not only do wetlands have water storage capabilities in their soils, they have it in their plants.

Water in wetlands is either released naturally and slowly over time to groundwater supplies, streams, or it evaporates. It can also be physically forced out by someone or something draining it.

As you have read above, water sticks to water better than dry objects so it would make sense that in order for a wetland to do its job, it needs to be wet. So draining wetlands may not be the best idea if you want to have a good functioning wetland.

Putting the pieces together.

So the long and short of it is both sponges and wetlands:

  • have been created (either by man or nature) to absorb water using a similar design with lots of small spaces surrounded by a material (either the sponge or soil) to trap in the water
  • use the principles of water cohesion, and
  • release their waters slowly over time without interference or quickly by force.

This wetland's water carrying capacity has been reached. (Lani Wall)

This wetland’s water carrying capacity has been reached and is now overflowing due to excess rainfall. (Lani Wall)

But wait, you’re probably thinking if wetlands absorb water, do they have a limit as to what they can hold?

Yes they do! Just like sponges, wetlands have a carrying capacity.  So when the wetland becomes full you will see more pooling surface water, especially recently with all this rain we’ve been having in Delaware.

Now that you know how wetlands absorb and hold water, just think about how much more H2O you would see on our land surfaces if wetlands weren’t there or if a wetland’s soil pores got clogged up from super dirty water…


Exploring Our Fluid Earth. (n.d.). Hydrogen Bonds Make Water Sticky. Retrieved from

Nelson, S. A. (2015, November 11). Groundwater. Retrieved February 27, 2019, from

Turner, Nicholas. An essay on draining and improving peat bogs; in which their nature and properties are fully considered. By Mr. Nicholas Turner, of Bignor, Sussex. London,  MDCCLXXXIV. [1784]. Eighteenth Century Collections Online. Gale. CIC Penn State University. 25 Feb. 2019. <>.

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Great things come naturally in Laurel, Delaware: Wetlands and bioswales

Written on: March 11th, 2019 in Wetland Restorations

Ground breaking ceremony of the Tidewater Park. Jules Bruck.

Ground breaking ceremony of the Tidewater Park.

Guest writer: Jules Bruck, University of Delaware

Great things come naturally in Laurel, Delaware including the new green infrastructure treatments that are popping up along the Broad Creek – home to the future Laurel Ramble.

This past summer the Sussex County Conservation District broke ground on a parcel of land in the center of the Ramble plan called Tidewater Park. The project, designed to improve water quality in the area, was engineered by ForeSite Associates of New Castle, DE.

Work began on two treatments – a vegetated bioswale and a constructed wetland, in early summer 2018.

The bioswale

The Problems: Left image was taken of Broad Creek during a normal rain event in spring 2016. Photo credit: Matt Parker. Right, image taken of Broad Creek during historical flooding event on September 30, 2016. Photo credit: Ed Lewandowski

The bioswale was selected as a priority treatment due to the following factors:

  • location high in the watershed of the Tidewater Park project area,
  • ability to provide the bulk of water quality treatment for the contributing upstream and previous areas,
  • ability to improve the drainage characteristics of the project site, and
  • it’s form.

The 300’ long gently meandering bioswale forms a diversion for runoff, permitting easier installation of the constructed wetland and fish habitat. It creates a viable, ecologically appropriate solution to aid in reducing pollutant loads to Broad Creek, which in turn makes a significant step forward toward meeting the demands of the town’s Municipal Separate Storm Sewer System (MS4) permit.

The bioswale represents a permanent change in drainage patterns on site, and it is expected to be a long-lived treatment as long as the inlet is regularly inspected and maintained. It’s designed to meet the total maximum daily load (TMDL) requirements for 2.23 acres of existing impervious surface in the drainage area.

The Ramble Plan has driven efforts to redevelop Laurel's waterfront since its acceptance in 2013.

The Ramble Plan has driven efforts to redevelop Laurel’s waterfront since its acceptance in 2013. The project site is located on the north side of the river in between the 28A and Alt 13 bridges.  Click on the image for a larger view.

The constructed wetland and tidal fish cell

The constructed wetland is approximately one acre is size, and planted with native grasses and sedges as well as some flowering herbaceous plants.  It was designed to accept some stormwater surface flow from the upland areas as well as to allow the waters of the Broad Creek to enter during high tides.

According to the Stormwater Management Report prepared by FA in July 2016, “In keeping with the theme of the proposed playground as a nature-based feature and the Town’s goal to promote Laurel’s ecotourism industry, a tidal fish cell has been designed adjacent to the constructed wetland.”

“This tidal cell does not serve a regulatory function other than convey discharges from the constructed wetland to Broad Creek. Overflow from the constructed wetland is designed to discharge through a narrow v-shaped notch in the weir wall to help detain and slowly release runoff to the tidal fish area.”

This figure shows the constructed wetland and bioswale treatments as well as future park amenities. The parking lot has been removed from the plan so there is more room for park elements.

This figure shows the constructed wetland and bioswale treatments as well as future park amenities. The parking lot has been removed from the plan so there is more room for park elements. Click on the picture for a larger view.

Creating native wildlife habitat with native plants

The new landscape has diverse plantings that will increase the native biodiversity on site and attract wildlife such as ducks and butterflies. We look forward to the spring so we can evaluate how the plants survived over the winter.

We anticipate the wetland will become important habitat for spawning fish, such as American Shad. In fact, we had to be careful about working in the water during the summer to avoid disruptions during critical times for the local native fish.

Good planning = easy maintenance

After some minor touch ups and replanting of the plants that did not make it through the winter, the treatment should be relatively easy to maintain.

University of Delaware landscape architecture students worked on a landscape management plan under the direction of Dr. Jules Bruck thanks to funding from UD Community Engagement Scholars and DE Sea Grant. We continue to work with the Town of Laurel to develop a management plan.

We also want to keep an eye out for any invasive plants and provide training for the town’s landscape crews to help them identify and control non-native plants and noxious weeds. To that end, we’ve asked Tracy Wootten of Cooperative Extension to lend us a hand!

We are working on some ideas to engage facilities and the community so the project remains a benefit to all.

The Tidewater Park plan is a different type of landscape and you’ll start to see more of it as the Ramble plan is installed.  It’s not just ornamental, it’s a working landscape.

This project was funded through two grants – the DNREC Community Water Quality Improvement Grant and the DNREC Chesapeake Bay Implementation Grant Program. Interested in learning more about this wetland and bioswale creation or the Laurel Ramble? Visit the Reimagining Laurel website.

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Delaware Wetland Management & Assessment Program