Wetland and Water

In Commemoration of World Wetland Day 2021

Prepared by Rahanna Juman
Institute of Marine Affairs

We are in a growing water crisis that threatens people and our planet.  Water use has increased six fold over the past century and is rising by about 1% a year. We use more water than nature can replenish, and are destroying the ecosystems that water and all our life depend on most- wetlands.

Water covers about 70% of our planet, so we think that it is plentiful. However, freshwater—the stuff we drink and irrigate our farms with—is incredibly rare. Only 3% of the world’s water is freshwater, and two-thirds of that is tucked away in frozen glaciers or otherwise unavailable for our use. Therefore, some 1.1 billion people worldwide lack access to water, and a total of 2.7 billion find water scarce for at least one month of the year.  https://www.worldwildlife.org/threats/water-scarcity. To make matters worse, climate change will affect the availability, quality and quantity of water needed for basic human needs, thus undermining enjoyment of the basic rights to safe drinking water and sanitation for billions of people, warns the latest UN World Water Development Report (UNWWD), 2020.

According to the UNWWD Report 2020, climate change impacts such as the increasing frequency and intensity of extreme events – storms, floods and droughts, will aggravate the situation in countries already experiencing ‘water stress’ and generate similar problems in areas that have not been severely affected. Furthermore, the report highlights the fact that poor water management tends to exacerbate the impacts of climate change, not only on water resources but on society as a whole.

Wetlands, which include permanently or seasonally inundated freshwater habitats ranging from rivers to marshes, along with coastal and marine areas such as estuaries, lagoons, mangroves and reefs, sustain humanity and nature.  Wetlands hold and provide most of our freshwater (Ramsar@ramsar.org). They provide water storage, flood control, groundwater recharge and discharge, protection from storms and tsunamis, and water quality improvement. Basically, they filter the water that seeps into aquifers, helping to replenish this important water source.

Wetlands improve the quality of water flowing over and through them, a crucial function in nature’s own water quality restoration process. Wetland vegetation slows water flow and captures suspended sediment thereby reducing turbidity; that is the murky quality that makes some waters unattractive for swimming and other recreation uses. Wetlands also filter out, trap, and naturally recycle nutrients like nitrogen and phosphorous that run off from the land and might be harmful in excessive quantities in surface waters. This filtration process saves millions of dollars that might otherwise be required to build and operate facilities to perform this function (https://www.ramsar.org/news/wetlands-a-sustainable-solution-for-water-purification-and-security).

Wetlands can also capture pollutants like heavy metals, organic chemicals like pesticides and petroleum hydrocarbons, removing them at least temporarily and sometimes permanently from aquatic ecosystems. Unfortunately, when wetlands accumulate them, these harmful compounds can enter the food chain through wetland vegetation and wildlife, ultimately finding their way into fish and wildlife people consume.

In addition to providing clean freshwater for human use, wetlands protect us from water-related disasters such as floods, storms and tsunami.  Wetlands help to lessen the impacts of flooding by absorbing water, and reducing the speed at which flood waters flow. By holding back some of the flood waters and slowing the rate that water re-enters the stream channel, they can reduce the severity of flooding and erosion.  Floodplain wetlands, particularly, have the capacity to temporarily store flood waters during high runoff after torrential rain events.  While referred to as natural sponges that soak up water, wetlands actually function more like natural tubs, storing either flood waters that overflow riverbanks, or surface water that collects in isolated ponds. As flood waters recede, the water is released slowly from the wetland soils.

Mangrove forests, in particular, reduce both storm surge and tsunami wave impacts further inland (Marois and Mitsch, 2015). They can directly lessen wave action as their complex root systems enhance drag against wave energy.  Coastal communities are aware of the particular protection afforded by mangroves. In India and the Philippines, villagers tell of how they have been protected from cyclones and typhoons in locations where mangroves were intact, but suffer where mangroves have been converted to shrimp farms or were otherwise lost (Dahdouh-Guebas et al. 2005)

So as we celebrate World Wetlands Day 2021, let us truly appreciate our wetlands in Trinidad and Tobago and the roles they play in providing clean water for human use, and protecting us against natural disasters.  To help us understand the importance of our wetlands, the Institute of Marine Affairs (IMA) is launching a new book on Mangrove Forests of Trinidad and Tobago.  Written in simple and non-jargonised language, the book is a compilation of primary information generated by the IMA and other published literature. 

The intended users of this publication include public policy practitioners, economic decision-makers, land-use planners, students at secondary and tertiary levels and members of the general public. It is hoped that once citizens understand the important role mangrove forests play to our economy, safety and sustainability, they would become meaningfully engaged in its conservation. We need to urgently step up the protection, sustainable management and restoration of wetlands as an essential element in integrated policies and actions for a healthy planet. 

Reference

Dahdouh-Guebas, F., Jayatisse, L. P., Di Nitto, D., Bosire, J. O., Lo Seen, D. & Koedam, N. 2005. How effective were mangroves as a defence against the recent tsunami? Current Biology 15 (12): R443-447

Marois, D. E., and Mitsch, W. J., 2015. Coastal protection from tsunamis and cyclones provided by mangrove wetlands – a review. International Journal of Biodiversity Science, Ecosystem Services & Management, vol. 11, No.1, pp. 71–83.

UN World Water Development Report 2020