Wetlands are a habitat of particular importance to managers in every type of watershed. Historically, wetlands were crucial in the survival of early civilizations. Along the Nile, Tigris, Euphrates and others, the riparian wetlands and floodplains were a source of nutrient-rich soil for early agriculture.
Over the past several centuries however, water resources have suffered due to population growth, urbanization and expanded agriculture, to the point where only a fraction of the world’s wetlands still exist. Over the past three decades, the US and other countries have begun to recognize the important services that wetlands provide to human society: from being an economically valuable food source for human populations, to providing filtration of pollutants and nutrients, to capturing and storing water, particularly after extreme events that might otherwise lead to flooding.
On the ecological side, wetlands are one of the most biologically productive habitats on the planet. Here in the US, nearly a third of our endangered or threatened species rely on such habitat for part of their life cycle.
In the modern world, where more and more people compete for a continually dwindling clean water supply, wetland protection is a key component in both providing a reliable source of drinking water and for ensuring the survival of numerous ecological communities. The degradation of the Aral Sea is a major example of poor water management. Around the world though, there are numerous examples of both good and bad practices involving lakes, rivers and wetlands. There is often a balancing act that takes place in protecting the interests of those who directly benefit from the existence of wetlands, and those, (such as agriculture) who may benefit from utilizing water that might otherwise feed wetlands.
Due to different regional needs and the seriousness of water shortages, techniques for balancing water allocations vary widely around the world. Because many areas suffer from even greater drought and environmental degradation than here in the US, we can look at other regions as models. In Turkey for instance, the Gediz River Delta is a major source of water, but there is not enough to serve all competing interests, regardless of how the resource is managed. Large amounts of water are allocated to providing low-saline wetland habitat for endangered bird species. However, this allocation means that less water is available for upstream agricultural use, and this results in lower crop yields during drier seasons. The Gediz also suffers from poor water quality due to a high urban growth rate, factory waste, salt production and agricultural runoff, typical problems for water supplies around the world. In the end, allocation comes down to meeting an adequate ecological threshold, factoring in the costs of various actions, and recognizing that crop yields may be down depending on the water supply.
In many populated areas around the world, groundwater is extracted faster than it can be replace through natural means. Drought and climate change add to the problem, exacerbating the water shortage that impacts not only humans, but also destroys wetlands and the plants and animals in them. (For reference, see blog posts on water and on dioxins.)
According to the WETwin project, which is sponsored by the European Commission to study and enhance the quality of wetlands, there are a number of successful wetland projects in development. For instance, regions in Africa have had some success in utilizing wetlands as a tool for water treatment. Where infrastructure is not well developed, wetlands are a low-maintenance, cost-effective way to purify water supplies. In parts of East Africa, wetlands managers have successfully integrated fisheries and crop production with the natural hydrological flow, minimizing the impact on the environment while still benefiting agriculturally. In other areas of the world, ancient fishery practices are being adapted to riparian wetlands in order to achieve a sustainable balance between habitat protection and the benefit of humans.
In terms of pollution, there is certainly a downside to integrating human and wetland water needs, as demonstrated in one study conducted to determine the effect of using wastewater effluent on wetlands. Because human populations use so much water, we are sometimes left with having to find alternative ways to provide enough water to habitats like wetlands, particularly those that require greater levels of management. One technique seeing increased use is to feed wastewater into wetlands. From a habitat management perspective, it is a way of controlling water levels without decreasing water supplies that might otherwise be needed for human consumption. However, despite the nutrients that a wetland might be able to use and sequester, wastewater also contains higher levels of salts and other pollutants that have been found to actually impede seed and plant growth over time, and alter the natural hydraulic conductivity of soils. The research suggests that, in some cases this type of water allocation may not be the best long-term choice.
Here in the US there are a number of projects and policy initiatives that have the potential to improve wetland environments and their associated ecological services. Since 1989, in the U.S. we’ve had a policy of “no net loss” of wetlands. In theory, measures should be in place to ensure that overall wetland loss does not occur. When damage to wetlands is unavoidable, an equal amount of habitat is generally created, improved or protected. While it’s debatable to what extent we’ve actually halted or reversed the loss of wetlands, “no net loss” is a tool which federal and state policy makers and environmental managers can and should use to protect and restore wetlands. In Montana, for instance, there is currently a proposed rule designed to better integrate wetland water rights into existing state water rights laws. The aim is to provide greater protection to water supplies, while at the same time working toward a policy of no net loss. Understanding the basic advantages of wetlands and the benefits they provide to the recharge of aquifers, the Montana rules lay out important guidelines, including defining wetland protection as a beneficial use of water allocations, and the need to include vegetation and wildlife habitat as important factors in enhancing water supplies.
Another forward-looking initiative worth mentioning as a potential model for regions around the country is the East Fork Reuse Project in Texas. Forecasting an increase of 700,000 people in the North Texas Water District over the next decade, planners are constructing a 1,840-acre wetland that will be fed by the Trinity River, in order to remove the vast majority of sediments and nutrients (nitrogen and phosphorus) carried in the water. The purified water from the wetland would then be mixed with other raw water sources to provide the necessary supplemental water. While the project is estimated to cost $246 million, it will benefit wetland species, and provide far more water for the growing population than would water conservation measures alone.
Like most environmental problems, wetlands and water allocations involve finding a balance between human needs and those of the environment. In the end, water is limited, but still needs to be managed and shared in an equitable manner. Proper management in the future will require a better understanding of water requirements and the ecological services that we benefit from by maintaining healthy wetlands. There is a need to find better ways to control development and urban population growth. Also, the cost and social benefits of protecting and enhancing wetlands will need to be weighed against not protecting this habitat and also the time and monetary expense of finding other sources of water.
Chris Watts currently serves as an Environmental Regulation Expert at Actio Corporation in Portsmouth, NH. He is pursuing advanced studies in Environmental Science at Johns Hopkins University, Baltimore, MD.