How to protect estuaries

To maintain these functions, estuaries need our care and protection.

We impact estuaries in many ways. To care for and protect estuaries, we need to consider how our actions affect estuaries and take steps to reduce this impact.

Generally, the quality of New Zealand coastal habitats is high by international standards. However, estuaries near urban development are under stress , and action can be taken to alleviate this.

Helping to protect estuaries

  • Plant trees: The biggest problem for estuaries is sedimentation. Land clearance has been a major contributing factor to sedimentation. Experts estimate that about 390 million tonnes of sediment washes from the mainland into the sea every year, affecting estuaries. Native vegetation can be planted alongside rivers and streams that enter estuaries and along estuary margins to help stop erosion and trap sediment and nutrient run-off into the estuary.
  • Fence off stock: Landowners around estuaries can fence off streams from stock so that they do not cause streambank erosion of sediment or deposit nutrient-laden effluent into the water that will flow into the estuary. Fencing will also protect planting along riparian (waterway bank) margins as above.
  • Improve catchment Improved catchment can help limit pollution that enters estuaries through stormwater run-off. This is important following heavy rainfall. Stormwater brings many pollutants from the land into estuaries through drainage systems.
  • Restrict fishing activities: Pay attention to regulations that limit quantity and size of fish and shellfish that can be taken to prevent excessive harvesting.
  • Respect marine reserves: Do not take marine life from these areas.
  • Biosecurity checks on ships: Ships arriving from overseas are checked to prevent the invasion of exotic species.
  • Stop reclaiming land: Stop reclaiming land from estuaries.
  • Limit pollution: Help to keep the estuary healthy by not adding solid waste or liquid pollution. Don’t pour harmful substances such as oil, detergent or paint into an estuary or allow these materials to go down stormwater drains that lead to estuaries. Boat owners need to prevent spillage of fuel or detergent into water when refuelling or cleaning boats.
  • Report threats to estuaries: Let your local council know if you see something that could be a risk for an estuary – like illegal dumping of rubbish, pollution spills, strange new marine organisms or people cutting down or removing estuarine plants such as mangroves without a permit.

Traditional practice

All societies affect the environment they live in. For example, before Europeans arrived, Māori hunted the moa (a giant, flightless bird) to extinction. Perhaps for reasons like this, Māori developed an intimate relationship between themselves and their environment. Their customary practices maintained a balance between communities and the environment. Resources were managed sustainably. Some of their practices included:

  • setting temporary restrictions (rāhui) on harvesting from certain areas
  • using the moon (maramataka) to guide harvesting
  • banning recreational fishing and birding
  • harvesting only what was needed
  • harvesting at the right time (not during breeding season)
  • limiting fishing, particularly when fishing with a large net (for example, using it once a year).

The Māori name for Huntly is Rāhui Pōkeka. This name came about during the time of the ancestors, a pōkeka was driven into the ground to signify that a rāhui had been put on fishing for eels until they were restocked. This shows that the principles of kaitiakitanga were upheld in the early days.


Traditionally, Māori have always monitored resources, such as kaimoana, and made decisions about conservation measures, such as rāhui and today this continues as an important part of their role as kaitiaki.

Kaitiakitanga means guardianship or protection. It includes environmental conservation and sustainability based on a traditional Māori world view, which recognises the connection between Maori and the natural world.

Learn more about kaitiakitanga from the work of the Waikato-Tainui people to restore their awa.

Nature of science

Scientific research sometimes reveals environmental problems – such as human impact on estuaries. This can give people the opportunity to respond – becoming science citizens who work with scientists on solutions to the problems.

Related content

The main impacts affecting estuaries are sedimentation and pollution from run-off. These issues are explained in the articles Human impacts on estuaries and Estuaries and farmland run-off. Working together to restore the Ōngātoro/Maketū Estuary looks at the role of participatory management between Māori, local government and others.

As a topic, estuaries have the potential to combine conceptual scientific understanding, cultural awareness and thinking about socio-scientific issues. Estuaries – a context for learning uses Hub resources to suggest four planning pathways as starting points for contextual-based learning.

Activity ideas

Students can use the Hubbub Estuary activity to identify estuarine impacts and protection actions.

These activities below are simple but effective hands-on models, demonstrating the land and water interface and potential impacts:

Healthy estuaries support the vitality and livelihoods of coastal communities. We gather with friends at estuaries to go fishing, kayak and spend quality time with each other. But we don’t always show estuaries as much love as they show us.

In college, I spent my days staring into my microscope at what can only be described as other-worldly – tiny stars, sunburst shaped disks and alien-like critters. I was examining plankton collected from a nearby estuary—these microscopic larvae would grow up to be crabs and oysters, which spend the beginning of their lifecycle in estuaries, the nurseries of the ocean. Estuaries provide essential habitat for marine life, including over 75% of commercially caught fish in the United States, and support recreational fisheries too.

Beginning my science career at The Evergreen State College, I was fascinated by the natural world. After graduating, I wanted to figure out how to use my science to help communities impacted by environmental challenges. This led me to apply to the Roger Arliner Young Marine Conservation Diversity Fellowship on the ocean acidification team at Ocean Conservancy. The position gave me the opportunity to learn exactly how science can help inform public policy. One of my cornerstone projects for the fellowship has been examining the impact of ocean acidification in estuaries, and how ocean acidification interacts with other environmental stressors and processes.

Located near densely populated areas, estuaries are influenced by both human and environmental stressors. Impacts like nitrogen run-off can often lead to harmful algal blooms (HABs), which are dangerous for people and fish. Also, ocean acidification has been measured in the open ocean, but it’s much harder to detect in estuaries and coastal zones because of converging processes like pollution, erosion and upwelling. If scientists can’t precisely measure how water chemistry is changing in these ecosystems, the effects are difficult to prepare for. Adding even more complexity, estuaries themselves are constantly changing as freshwater meets saltwater, tides rise and fall and species change seasonally. We simply don’t know yet how all of these factors influence each other in estuarine environments.

Working with our government relations team, we met with Congressional leaders passionate about estuaries to talk about my research and see if there was a way to advance what we know about ocean acidification in these busy ecosystems. These leaders in the estuarine space—Reps. Bill Posey, Brian Mast and Suzanne Bonamici—have now introduced the National Estuary and Acidification Research (NEAR) Act of 2018. This bill calls for a National Academies of Science study to look at how ocean acidification and other human and natural stressors interact in estuarine environments so that we can adequately prepare for the future.

In the last ten years, federally funded research on ocean acidification has shown that we must understand acidification in estuaries and coastal zones too, despite how difficult the research can be. Taking care of these places of other-worldly wonder requires understanding them better—and the NEAR Act of 2018 brings us one step closer. This legislation will help us steward coastal resources better and protect the estuary environments that we depend on for food, jobs and recreation.

Trading in my microscope for a job in conservation seemed like a big leap at first, but the sense of wonder that science inspired in me was matched by the incredible team I was fortunate to work alongside. From my own research to collaborating with my team, to educating Congressional leaders, I’ve learned that protecting the coast requires passionate individuals and skills as dynamic and nuanced as our beloved estuaries.

We manage estuaries to protect them from threats including coastal development and natural weather events.

How to protect estuaries

The health and integrity of estuaries is vital in maintaining environmental, social and cultural values and ecosystem services. This strongly benefits the communities that interact and depend on them.

Why we protect estuaries

Estuaries are valuable environmental assets that are under increasing pressure. With more than 80% of New South Wales’s population living on or near the coast, coastal local government areas are rapidly developing and growing faster than those elsewhere in the State.

Estuaries are at risk from extreme weather events. Climate change projections suggest that extreme rainfall events will increase in frequency and intensity. Extreme rainfall events and large damaging storms can cause flooding in rivers and estuaries as well as flash flooding. They can also cause soil erosion and water pollution, threatening natural estuarine ecosystems, commercial enterprises and public amenity.

How we protect and manage estuaries

To help protect and improve the health of estuaries we:

    monitor condition and the physical properties of estuaries, to help in the application of the risk-based framework for achieving waterway health outcomes and the development of water quality and river flow objectives
  • provide support and guidance to council’s developing their coastal management programs for estuaries and open coast areas to help local councils plan and implement estuary management projects, manage risks from coastal hazards, restore coastal habitats and improve estuary health.

Data collection, risk assessment and monitoring expand

We have collected data on the physical characteristics of 184 estuaries in NSW. We continue to measure and record estuary conditions, including tidal flow and water and quality.

Our scientists have also developed a risk assessment tool, the Coastal Eutrophication Assessment Tool or CERAT, to help protect and preserve the health of estuaries.

We monitor and report on the health of NSW estuaries through the NSW Monitoring, Evaluation and Reporting Program (MER).

Funding and technical assistance expand

We work to support local government and communities manage estuaries.

Technical and financial assistance is available for managing risks from coastal hazards, restoring coastal habitats and improving estuary health through our Coastal and Estuary Grants Program. We also provide councils, public authorities and communities with advice about preparing a coastal management program.

Ecosystem Services are the benefits nature provides to people. In addition to the ecosystem services previously discussed (economic, cultural, and ecological benefits), estuaries provide water filtration and habitat protection.

Salt marshes are one type of estuarine habitat that acts like an enormous filter, removing pollutants such as herbicides, pesticides, and heavy metals out of the water flowing through it. In addition to pollutants, the same water often brings with it all of the nutrients from the surrounding watershed. A watershed, or drainage basin, is the entire land area that drains into a particular body of water, like a lake, river, or estuary. The nutrients flowing into an estuarine habitat often provide for lush plant growth. For this reason, estuaries are some of the most fertile ecosystems on Earth. Yet, due to the pollutants they extract from waters running through them, they may also be some of the most polluted as well.
In the animation above, as groundwaters flow into the salt marsh from the surrounding drainage area, marsh grasses and the surrounding peat extract excess pollutants and nutrients from it. View an animation showing how estuaries serve as nature’s water filters.

Habitats associated with estuaries, such as salt marshes and mangrove forests, act like enormous filters. As water flows through a salt marsh, marsh grasses and peat (a spongy matrix of live roots, decomposing organic material, and soil) filter pollutants such as herbicides, pesticides, and heavy metals out of the water, as well as excess sediments and nutrients.

One reason that estuaries are such productive ecosystems is that the water filtering through them brings in nutrients from the surrounding watershed. A watershed, or drainage basin, is the entire land area that drains into a particular body of water, like a lake, river or estuary. In addition to nutrients, that same water often brings with it all of the pollutants that were applied to the lands in the watershed. For this reason, estuaries are some of the most fertile ecosystems on Earth, yet they may also be some of the most polluted.

Estuaries and their surrounding wetlands are also buffer zones. They stabilize shorelines and protect coastal areas, inland habitats, and human communities from floods and storm surges from hurricanes. When flooding does occur, estuaries often act like huge sponges, soaking up the excess water. Estuarine habitats also protect streams, river channels, and coastal shores from excessive erosion caused by wind, water, and ice.

Unlike economic services, ecosystem services are difficult to put a price on, but economists have developed methods for determining their value. These values are used regularly and for issues related to coastal policy and decision-making.

Oregon’s coastline is blessed with 22 major estuaries from the mighty Columbia River Estuary that separates Washington and Oregon to the small Winchuck River Estuary near the California border. Where Oregon’s forests and rivers meet the ocean, estuaries are the engines that power salmon, water birds, Dungeness crab, oysters, forage fish, cultural resources and jobs for many in coastal communities. Estuaries are also key to the calculus of climate change in the region: protecting estuaries helps store greenhouse gases, mitigate ocean acidification, and safeguard coastal communities from increased storms and floods.

How to protect estuaries

Eelgrass – a marine flowering plant found in bays and estuaries – has particularly high value given the co-benefits this habitat provide for wildlife, people, and the climate. Yet, eelgrass and other seagrasses are disappearing because of pollution, dredging, development, sea level rise and other impacts.

Oregonians have a new opportunity to help protect eelgrass and the estuaries that are so important for marine life and our economy. The State of Oregon has embarked on an effort to update its estuary management plans originally written in the 1980s. By engaging in this process, you can have a role to assure healthy estuaries for future generations of Oregonians.

How to protect estuariesYaquina Bay viewed from Paddle Park, Lincoln County, Oregon. Photo by Bobby Hayden

Eelgrass Importance and Threats

Eelgrass and other seagrasses found in estuaries, bays, and other shallow nearshore areas, provide many important ecological functions and ecosystem services including:

  • Coastline protection: buffer against coastal storms by absorbing wave action preventing sediments from washing away.
  • Improve water quality: acts as a water filter and purifier by absorbing pollutants and reducing the frequency of harmful algal blooms.
  • Fish Nursery: provide breeding grounds for many fish and invertebrate species including commercially important species like salmon, rockfish, Dungeness crab, and Pacific herring. This habitat is so important for fisheries that NOAA declared it as Essential Fish Habitat in 1996.
  • Buffer against climate change : Eelgrass absorbs and stores carbon acting as a “carbon sink”. Research also indicates eelgrass’s carbon sequestration can moderate the impact of ocean acidification that inhibits some marine life, like oysters and crabs, to form shells.
  • Help birds: migratory birds, like the Pacific Black Brant, feed on eelgrass. Estuaries, in general, are important as migratory stopover areas for many bird species providing critical places for bird to rest and build up energy reserves. In fact Portland Audubon identified 15 Oregon estuaries and bays as Important Bird Areas (IBAs) which are focal areas of conservation importance for bird species. These sites support thousands of migratory shorebird, waterbird, and waterfowl species including species of concern like the Red Knot, Dunlin, and Black-bellied Plover.

Oregon has lost an estimated 24% of estuary habitat since the 1870s. This loss has slowed since the 1970s but eelgrass in Oregon is still threatened and disappearing. Dredging harbors can destroy or degrade eelgrass beds. Pollution, particularly from toxic runoff can add excess nutrients into the system causing harmful algal growth. Logging releases sediment into estuaries reducing water quality damaging eelgrass, introduction of invasive non-native plants can outcompete eelgrass, sea level rise and other impacts related to a warming climate negatively impact eelgrass.

Oregon Estuary Management Plan Update

The State of Oregon has embarked on an effort to update its estuary management plans originally written in the 1980s. These original plans tend to emphasize development and minimize ecological concerns, do not address climate change issues, came before species like Coho salmon were even listed as endangered, do not embrace habitat restoration as a tool, did not involve coastal Tribes nor address legacy impacts to the estuary including disturbance of cultural resources, and need to incorporate state and federal policies and programs have emerged since plan adoption so they are in much need of updating. The Yaquina Bay Estuary Management Plan process is just getting underway and, when completed, will be looked at as a blueprint for subsequent estuary plans in Oregon. Ultimately, we would like to see Oregon update all estuary plans to provide the strongest habitat protections possible to ensure a vibrant economy. We also encourage a policy that provides stronger eelgrass protection like the California Eelgrass Mitigation Policy which provides a framework for coordination between federal and state agencies to ensure no net loss of eelgrass.

How to protect estuariesA map showing all the Important Bird Areas along the coast.

On January 13th 2021, H.R.4044, the Protect and Restore America’s Estuaries Act , was signed into law .

How to protect estuaries

Introduced to the House in 2019 through the Transportation and Infrastructure Committee and sponsored by Rep. Tom Malinowski (D – NJ), the act reauthorizes appropriations for the National Estuary Program until 2026 and nearly doubles the annual funding authorization .

It also expands the range o f supporting projects which would qualify for grants and recogniz es the increasing threats towards estuaries such as p ollution, accelerated land loss, and risks to biodiversity .

These actions demonstrate a clear recognition by Congress of the economic and environmental importance of wetlands and coastal environments in the United States.

Representative s Lizzie Fletcher (D – TX) and Garret Graves (R – LA) joined Representative Malinowski as original cosponsors of the bill when it was introduced in July , 2019. The Act received 26 bipartisan cosponsors and passed th e House in February and the Senate in December , 2020 .

The National Estuary Program was developed by the EPA in 1987 out of amendments to the Clean Water Act. It protects and restores water quality and ecological integrity of 28 estuaries of national significance on the Atlantic, Pacific, and Gulf coast s as well as Puerto Rico.

The program also works with local communities to maintain ecological integrity, protect against environmental threats, and develop long term conservation plans. Funding is used to support grants and research proposals advancing the mission of the P rogram.

Restore America’s Estuaries manages the National Estuary Program Coastal Watershed Grants on behalf of EPA. On January 27 th , we will be announcing the awardees for the 2020 funding cycle live on Z oom. For more information, click here .

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This is NOT Internet Explorer

Published September 23. 2021 12:41PM | Updated September 23. 2021 10:49PM

By The Day Editorial Board

It has been rightly observed that knowledge is power. This includes the power to be forewarned, to prepare, to protect, and to share that knowledge with others.

This is why it is exciting to hear that Connecticut will soon receive its first National Estuarine Research Reserve designation and it is right here — in the case of some folks, literally — in our backyard.

Once in place, the research-reserve designation will make it easier for research institutes to tap federal grants. The resulting growing knowledge will provide information on how to better protect estuaries, to project how they will be affected by climate change and rising sea levels, to identify invasive species and prepare strategies to counter them, and to better understand how human-produced contaminants affect these environments.

Estuaries are the places where fresh water meets the salty ocean. The realization of their vital importance to many species, to providing ecological balance, and prevent erosion only grows with the research about them.

The application to the National Oceanic and Atmospheric Administration’s estuarine reserve program is a joint effort of the state Department of Energy and Environmental Protection, the University of Connecticut’s Marine Sciences Department operating out of the Avery Point Campus in Groton, and Connecticut Sea Grant. Official designation is expected early next year.

The public is urged to support the designation during a virtual public hearing on Oct. 7 or through the public commenting option that extends to Oct. 18. For information visit

Included in the research reserve would be many familiar locations, including Bluff Point, Avery Point, and Haley Farm State Park in Groton, and the Roger Tory Peterson National Area Preserve in Old Lyme. The 50,000-acre area includes eastern Long Island Sound from Mason’s Island west to the mouth of the Connecticut River, including the lower Thames River.

In a nod to the reality of industrial development, it will not include the areas of the Thames River near Electric Boat or Millstone Power Station on the Waterford-East Lyme border.

Not incidentally, the research reserve designation also includes an educational and informational element to help us all learn more about estuaries and why it is so important to protect them.

The Day editorial board meets regularly with political, business and community leaders and convenes weekly to formulate editorial viewpoints. It is composed of President and Publisher Tim Dwyer, Managing Editor Izaskun E. Larrañeta, staff writer Erica Moser and retired deputy managing editor Lisa McGinley. However, only the publisher and editorial page editor are responsible for developing the editorial opinions. The board operates independently from the Day newsroom.

How to protect estuaries

An estuary is a coastal area where freshwater from rivers and streams mixes with saltwater from the ocean. Estuaries are protected from the full force of the ocean by mudflats, sandspits, and barrier islands. You’ll find estuaries all over the world, and there are lots of different names for them. Estuaries are sometimes called bays, lagoons, harbors, or sounds. All of these places are estuaries if fresh water mixes with salt water.

In the Zone

How to protect estuariesThere are usually three zones in an estuary. The first zone is where the river begins to meet the saltwater. It has more fresh water than saltwater. Next is a middle zone where there is an almost equal mix of fresh and saltwater. The last zone is where the water begins to flow into the ocean and is mostly saltwater.

A Place to Call Home

How to protect estuaries

There are lots of different types of habitats in and near estuaries. Freshwater and salt marshes, sandy beaches, mud and sand flats, mangrove forests, river deltas, tidal pools, and swamps can all be part of the estuary.

Something Rotten

How to protect estuaries

Estuaries are full of decaying plants and animals. This makes the soil of estuaries rich in nutrients. Because the soil is so rich, lots of different plants grow in estuaries. The plants attract lots of different animals to the estuary and those animals attract other animals to the estuary. Common animals include: shore and sea birds, fish, crabs, lobsters, clams, and other shellfish, marine worms, raccoons, opossums, skunks and lots of reptiles.

Rock-a-Bye Baby

Estuaries are often called the nurseries of the ocean. Many fish species lay their eggs in estuaries. The abundant plant life in estuaries provides a safe place for young fish to live.

For the Birds

How to protect estuariesBirds are also abundant in estuaries. Between the plants and the fish and other animal life, there’s lots for them to eat. Many migratory birds like the Canada Goose use estuaries as resting and feeding places when they migrate. Long-legged birds like sandpipers, great blue herons, great egrets, and green herons are common in estuaries. Their long legs are perfect for wading in the water and their long toes make walking in the mud easy! Their bills are adapted for catching and eating fish, worms, crabs, and other invertebrates that live in the estuary.

For Your Protection

How to protect estuariesEstuaries are more than just a place for animals and plants to live. They also help control pollution. Water from upland areas often carries sediment and pollutants. The marshy land and plants in estuaries filter these pollutants out of the water. The plants in estuaries help prevent shoreline erosion. Estuaries also protect inland areas from flooding and storm surges. When a storm hits, estuaries often absorb water from the storm before it can reach upland areas.

Show Me the Money

How to protect estuaries

Estuaries play an important role in the U.S. economy. They attract tourists who like fishing, boating, and other water sports. They are an important part of the shipping industry because there are many industrial ports located in estuaries. Estuaries are also a critical part of the commercial fishing industry. It is estimated that over 75% of all the fish that are caught by commercial fishing operations lived in an estuary for at least part of their life cycle.

Estuaries in Danger

How to protect estuariesPollution from upland areas often damages estuaries. Dams can block natural stream and river routes and cut off freshwater from estuaries. When that happens, the fresh and saltwater balance of the estuary is changed and the estuary can be seriously damaged. Development can damage or even destroy estuaries. In the past, many people thought estuaries were wasted land and many estuaries were filled in and built on. Today, we are much more aware of the important role estuaries play in the environment, and many people are working to save these areas.

An Estuary Near You

There are many estuaries in the United States. You might even live near one! Check out the links below to find out more about an estuary near you and what you can do to help preserve these important ecosystems!