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Natural wetlands

Objective: 
Sectors: 
Organisation: 
UNEP-DHI Partnership – Centre on Water and Environment
Technology group: 
Body: 

Description

Natural wetlands are ecosystems that are either permanently or seasonally saturated in water, creating habitats for aquatic plants and conditions that promote the development of hydric (wetland) soils. There are various types of wetlands, including: marshes, swamps, forested wetlands, bogs, and wet meadows, as well as coastal wetlands such as mangroves. The ability of wetlands to retain large volumes of water, which they release slowly, makes them important for combatting extreme weather conditions such as flood control and drought mitigation, that occur more frequently as a result of climate change. Additionally, wetlands contribute to water purification, water regulation, biodiversity, aesthetics and recreation.
On ground interventions to utilize wetland ecosystem services for climate benefits may include wetland restoration or conservation activities (avoided degradation). Wetland restoration is the reestablishment of a degraded wetland. Degradation often results from drivers such as agricultural activities, land development for property, and others. Restoration interventions should aim to restore the original hydrology and topography of the wetland so that natural processes and ecosystem services delivering water storage and regulation benefits can be maintained.

Implementation

Initial stages of work should include assessment of the wetland’s current state and degradation rates of ecosystem services (if relevant), as well as identification of the main drivers of degradation. Hydrological modelling and analysis should inform assessment of the wetland’s expected retention capacity, as well as the additional ecosystem services provided to communities that may result from intervention. The on ground work typically includes interventions for mitigating the drivers of degradation and restoring natural wetland functions, depending on what is feasible and deemed appropriate for the specific location. Implementation of ecosystem services through targeted restoration may also be included. Long term sustainability of restoration and management projects often requires establishment of new management and monitoring frameworks (e.g. specific land use restrictions or arrangements with local land users, payments for ecosystem services schemes, etc.) in addition to the physical restoration activities. Such frameworks should include arrangements for monitoring the state of the wetlands over time, including ecological health and efficiency of ecosystem service delivery, along with key water variables.

Environmental Benefits

- Provides natural water regulation and purification processes. Wetlands trap sediments, decreasing the transport of sediments to downstream deposits and maintaining natural environmental flows.
- Combats extremely dry and extremely wet weather conditions, for example flood control and drought mitigation.
- Promotes very productive ecosystems and provide habitats to diverse species.
- Provides carbon storage and sequestration (certain wetlands, such as peatlands), which is vital for climate change mitigation.
- Protects low-lying coastal communities against storms and flooding from the sea, and stabilize the shoreline soils, reducing the risk of erosion.

Socioeconomic Benefits

- Regulates capacity. Sediment regulation, in particular, can play an important role in dam operations and hydropower production.
- Provides aesthetic and recreational value for local populations.
- Creates new income possibilities for local communities, for example through tourism or fishing activities. 

Opportunities and Barriers

Opportunities:
-    The long-term social and economic benefits from wetlands are exceptionally high, and can be enjoyed by a wide group of stakeholders
-    Wetlands are a natural part of the environment, and thus often no active construction activities are required 
-    Natural wetlands have multiple benefits, thus investment can deliver environmental (and socioeconomic) benefits on a number of fronts
-    They reduced infrastructure investments by utilizing nature based adaptation interventions

Barriers: 
-    Wetland degradation sources can be complex and multifaceted, often making it challenging to eliminate them
-    Objectively quantifying and valuing some of the ecosystem services provided by wetlands is challenging
-    Restoration and management of wetlands to a healthy state (or full capacity of water service delivery) can be costly and time-consuming
-    There are several types of wetlands, and the services and characteristics vary. Not all wetlands have the same functions and services. Certain types have low water retention capacities and would not be as effective in combatting extreme weather compared to those with a high retention capacities

Implementation considerations*

Technological maturity:         4-5
Initial investment:         2-4 (depending on alternative land uses and the causes of degradation)
Operational costs:         1-4 (depending on management arrangements required)
Implementation timeframe:     3-5

* This adaptation technology brief includes a general assessment of four dimensions relating to implementation of the technology. It represents an indicative assessment scale of 1-5 as follows:
Technological maturity: 1 - in early stages of research and development, to 5 – fully mature and widely used
Initial investment: 1 – very low cost, to 5 – very high cost investment needed to implement technology
Operational costs: 1 – very low/no cost, to 5 – very high costs of operation and maintenance
Implementation timeframe: 1 – very quick to implement and reach desired capacity, to 5 – significant time investments needed to establish and/or reach full capacity
This assessment is to be used as an indication only and is to be seen as relative to the other technologies included in this guide. More specific costs and timelines are to be identified as relevant for the specific technology and geography.

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