Floodplain restoration is the process of fully or partially restoring a river's floodplain to its original conditions before having been affected by the construction of levees (dikes) and the draining of

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

s and

marsh In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in genera ...

es. The objectives of restoring floodplains include the reduction of the incidence of

flood A flood is an overflow of water (list of non-water floods, or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant con ...

s, the provision of habitats for aquatic species, the improvement of water quality and the increased recharge of

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

Description

Types/methods

Anthropogenic impacts on floodplain mostly target the lateral connectivity between rivers and their floodplains, so many restoration methods focus on removing human-made structures that disrupt connectivity. One type of floodplain restoration are levee setbacks and dam removal, either full or partial, to allow for rivers to migrate within a space that is closer to the natural floodplain.Pess, George R., et al. "Monitoring floodplain restoration." ''Monitoring stream and watershed restoration. American Fisheries Society, Bethesda, Maryland'' (2005): 127-166. Another method is through a "beaded approach" with allows small portions of a floodplain to be restored to natural habitat and functions . The removal of levees and/or

weir A weir or low-head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the water level. Weirs are also used to control the flow of water for outlets of l ...

s can allow for the reconnection of river channels to their floodplain. Riverside embankments through the creation of overflow sills and creating artificial opening at inflow channels can help increase channel connectivity to the floodplain. Restoring drained or degraded wetlands can help increase floodplain connectivity.

Potential benefits

Floodplain restoration can restore previously lost or degraded ecosystem services. These ecosystem services can be categorized by supporting, regulating, provisioning, and cultural services. Restoring floodplains can help regulate flood events and mitigate flood related damage. Floodplain restoration can also increase biodiversity by creating new or restoring degraded habitat and encourage growth of native species. Methods of wetland restoration in the floodplain, can help better water quality. Reconnecting rivers to their floodplains promotes carbon storage in soil and regulates processes within soil.

Challenges

There are several issues that may arise when planning and/or implementing floodplain restoration projects. Since floodplain restoration involves a wide range of partnerships and stakeholders, a lack of communication between parties and differences ideas or priorities for restoration goals can be a constraint for restoration projects. There is also the potential for a higher value or desire placed into immediate flood-defense and current land-use practices rather than the ecological or environmental benefits, which can stall or prevent floodplain restoration. It is also important to include the socio-economic aspects of floodplain restoration, so when this becomes a constraint to projects that do not consider these aspects. Restoration efforts need to be properly and continuously monitored to determine effectiveness and benefits.

Examples of existing projects

Africa

* Waza-Logone Restoration

Asia and The Pacific

* Tarim River,

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

case study focuses on the cultural, socio-economic, and environmental aspects of the basin to plan for restoration projects. *

Mekong Delta The Mekong Delta ( or simply ), also known as the Western Region () or South-western region (), is the list of regions of Vietnam, region in southwestern Vietnam where the Mekong, Mekong River River delta, approaches and empties into the sea th ...

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

restoration to aid with coastal protection. * Four Major Rivers Restoration Project in South Korea to restore the Han, Nakdong, Geum, and Yeongsan rivers.

Europe

One of the drivers for floodplain restoration is the EU Water Framework Directive. Early floodplain restoration schemes were undertaken in the mid-1990s in the Rheinvorland-Süd on the Upper

Rhine The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...

, the Bourret on the Garonne, and as part of the Long Eau project in England. Ongoing schemes in 2007 include Lenzen on the Elbe, La Basse on the

Seine The Seine ( , ) is a river in northern France. Its drainage basin is in the Paris Basin (a geological relative lowland) covering most of northern France. It rises at Source-Seine, northwest of Dijon in northeastern France in the Langres plat ...

and the Parrett Catchment Project in England. On the Elbe River near Lenzen (Brandenburg), 420 hectares of floodplain were restored in order to prevent a recurrence of the Elbe floods of 2002. A total of 20 floodplain restoration projects on the Elbe River were envisaged after the 2002 floods, but only two have been implemented as of 2009 according to the environmental group de:BUND. * Upper Danube River,

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

Restoration project.

Latin America and the Caribbean

* Chubut River Restoration Project

North America

Floodplain restoration in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

is driven by The Clean Water Act (1972), The Endangered Species Act (1973), and various state level legislations. * In the catchment area of the

Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Ea ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

* Emiquon Preserve on the

Illinois River The Illinois River () is a principal tributary of the Mississippi River at approximately in length. Located in the U.S. state of Illinois, the river has a drainage basin of . The Illinois River begins with the confluence of the Des Plaines ...

* Baraboo River in

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

. * Upper Sandy Creek a tributary in the Cape Fear River in

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

. * Efforts on the Oldman River and St Mary River, in

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

to restore the flow regime to encourage vegetation growth.Rood, Stewart B., et al. "Managing river flows to restore floodplain forests." ''Frontiers in Ecology and the Environment'' 3.4 (2005): 193-201.

References

{{Rivers, streams and springs Ecological restoration Flood control Stormwater management Water and the environment Water resources management Floodplains