The Challenges Facing Aquatic Ecosystem Restoration


Aquatic ecosystem restoration is a very broad term that can take many forms from habitat restoration of streams, rivers, lakes, estuaries, riparian corridors, islands, wetlands, beaches and vernal pools, to acid mine drainage, the control of invasive species, and dam removal for anadromous fish. The list is long and captures most habitats. 

Regardless of the type of project, the goal is to restore function to a degraded system and provide a more natural condition. Each restoration project will have its own unique challenges, but there are general challenges that typify most aquatic ecosystem restoration projects. 

I categorize the challenges as:

  1. problem and stressor identification
  2. planning difficulties
  3. funding
  4. communication
  5. willingness

The first challenge is to properly identify the problem and the stressors. Aquatic ecosystem projects that treat the symptoms and not the stressors causing the problem will never provide a successful solution. This may sound very simple, but in some environments, particularly in developed areas, it can be difficult to identify and address the true stressors causing the problem. For example, urban stream restoration projects often propose installing rock vanes or j-hooks or even full geomorphic alterations, but if stormwater runoff from uncontrolled impervious surfaces is the stressor degrading the system and no additional controls are put on those impervious surfaces to relieve the stress, restoration will not be achieved. 

" The watershed’s population has exploded to over 16 million people from approximately 12 million in 1980 and is projected to exceed 18 million by 2020"

Another complicating factor is that the true stressors may not be known. Often restoration scientists do not have a full understanding of how the natural system functions. The U.S. Army Corps of Engineers in partnership with the states of Maryland and Virginia and many other groups just completed a Programmatic Environmental Impact Statement for Oyster Restoration in the Chesapeake Bay. This study evaluated restoring the Chesapeake Bay using native oysters and a non-native species. Many roadblocks were encountered during this study, not only due to uncertainties with how the non-native oyster species would behave in the waters of the Chesapeake, but because many unknowns still exist with how the native species functions in the bay. Mother Nature has many secrets and we still do not understand fully how some systems work. 

This and other uncertainties make planning a restoration project particularly challenging. Typically, an aquatic ecosystem restoration project has four basic phases — planning, design, construction and monitoring. The planning phase must consider the uncertainties in the natural system as well as the uncertainties associated with the proposed restoration plan. Annual climatic variability is an unknown that affects project planning. Many systems, such as the Chesapeake Bay, behave differently depending on how much rain falls in spring and how high summer temperatures rise. It is difficult to propose a remedy to restore a problem when it is uncertain what form the problem will take in future years. As a result, many projects must consider a range of acceptable future conditions and include adaptive management and monitoring. 

A team of individuals within the U.S. Army Corps of Engineers evaluates the benefits of a proposed action and the value of those benefits during the planning phase. It is very important to be able to answer questions posed by decision makers regarding what they are going to achieve in return for the money they spend on a project. However, this is often one of the biggest challenges we face within the planning phase.

Chesapeake Wetlands
How much is an acre of wetlands worth?

We need to address many types of questions including: What is the value of an acre of wetland, open water, or a remote island in the Chesapeake Bay? Given limited funds, which of these habitats is most valuable? What is the benefit of installing a rain garden or restoring five acres of submerged aquatic vegetation? How far downstream will the benefit extend from installing stormwater controls on impervious acreage upstream? Tools exist to estimate the benefits, but few answers are inexpensive, field verified, or known for certain. Many times the benefits can be described, but definitive quantitative or monetary answers are not available.

To complicate matters further, many projects include a variety of fixes for the ecosystem problems at hand. For example, watershed restoration plans may include best management practices aimed at stormwater management, stream restoration, removal of fish passage blockages, trash control measures, and wetland, riparian corridor, and meadow restoration. Even though each practice has a different benefit, there is not a completely objective way to compare these differing practices. Prioritizations of these diverse projects are usually undertaken to recommend an implementation plan. Subjectivity is often introduced either through the development of the prioritization scheme or directly through best professional judgment. Either way, the process is open to great scrutiny because of the planning team’s judgment calls.

" Monitoring and adaptive management are necessary components of restoration projects to address the uncertainties of the future."

Another planning challenge is introduced when attempting to account for future changes in the system and the benefits that can be achieved in the face of these changes. This introduces another level of uncertainty. Most projects today must address climate change and/or sea level rise. Population changes and the spread of urban and suburban areas are other future conditions that must be considered. The Chesapeake Bay Program has been scrutinized for not restoring the Chesapeake Bay and missing its goals since its inception in 1983. Yes, many mistakes have been made, but the failures are rarely put in context. The watershed’s population has exploded to over 16 million people from approximately 12 million in 1980 and is projected to exceed 18 million by 2020 (CBP 1999). Although, more progress was expected and is needed, on one hand it is commendable that the line has been held in the face of this incredible increase in growth. 

Funding is a third major challenge facing aquatic ecosystem restoration. Not only do projects require money for planning, design, and construction, but for many larger projects a long-term reliable funding stream is necessary to fully achieve benefits. Multi-year restoration plans can be laid out to restore a watershed or a population of oysters but if funding is not stable from year to year, progress will quickly be derailed and project goals will not be achieved. Monitoring and adaptive management are necessary components of restoration projects to address the uncertainties discussed in the previous sections. However, these areas frequently experience funding shortages and budget cuts. Money can be obtained for constructing a project, but is often lacking for determining if it is functioning properly. This impairs future projects that look to past projects to understand if those practices are effective and how they function. There is a need for monitoring that identifies baseline conditions, answers targeted questions, and evaluates success. Costs can rise quickly on aquatic ecosystem restoration projects, but monitoring and adaptive management funding should not be sacrificed as these are the best ways to provide future cost-effective restoration measures and ensure success of current projects.

Our ability to overcome the last two challenges may likely determine whether we are successful in the restoration and management of our ecosystem resources. These two challenges are communication and willingness. Communication refers to our ability to explain why it is important to restore aquatic ecosystems. I believe there is starting to be a general understanding of the need for restoration but the message is not delivered completely. The local news runs stories on the impairments of the Chesapeake Bay and restoration efforts one night. Then the next evening, reports highlight the public’s outrage that water and sewer bills are going to increase because of upgrades at sewer plants. However, the connection between the two issues is not made. Particularly with watershed issues and stormwater management, the idea needs to be nurtured that it is every single person’s duty to take responsibility for the impact we have on our natural resources. Another restoration reality that needs to be effectively communicated is ‘patience.’ We all would like to see immediate progress and improvements, however, for many types of projects a time lag exists between the time a restoration project is completed and function is restored. The time lag is longer for larger, comprehensive projects­—those that are also very expensive. This further complicates these large projects because the decision makers have to justify the large expenditures today when in reality successful restoration may not be achieved for years or decades, long after a politician’s term has ended. Many aquatic ecosystems, particularly those in the urbanized East Coast, have been mismanaged for hundreds of years. They will not be fixed quickly. 

This leads into the last challenge: ensuring the political and public ‘will’ to achieve restoration. In the face of an acknowledged restoration lag, a project must achieve the will of current leaders and the public to take on the daunting problems even if success will not be immediately achieved. Only political will can provide the long-term funding streams discussed previously. The necessary ‘will’ is not only a challenge for large-scale restoration projects. Regardless of the size of the project, landowner willingness is key. Restoration seems to be migrating to more coordinated efforts and targeted projects in priority areas to make the most of short dollars and achieve concentrated benefits. However, the willingness of agencies to cooperate, and for landowners and communities to participate will determine what can be implemented and how effective it will be.


Chesapeake Bay Program (CBP). 1999. Population Trends. http://archive.chesapeakebay.net/pop.htm. Accessed 2 February 2010.


chesapeake bay, ecosystem, bay restoration, watershed, stormwater

Article Copyright:

Creative Commons License This article is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License

Article Disclaimer:

The views expressed in this article are those of the author(s) and do not reflect the official policy or position of Johns Hopkins University or the Johns Hopkins University Global Water Program.