Are nature-based solutions the answer to India's beach erosion problem?
Severe erosion is increasing coastal settlements’ exposure to storm surges and strong winds. Beaches are disappearing and livelihoods are being destroyed, requiring urgent interventions to be mapped out and executed. Goa, a state on the southwestern coast of India, is an evident example displaying the impacts of this phenomenon on communities and the environment. To make matters worse, grey infrastructure such as seawalls, designed to prevent beach erosion, is accelerating the process, leading researchers to doubt the efficiency of such interventions.
This is where nature-based solutions come into play, demonstrating how working with nature can mitigate societal challenges. In this case, mangrove restoration and conservation have the potential of reducing coastal erosion and protecting beaches.
Another nature-based solution that can increase coastal resilience is the restoration of oyster reefs, which purify oceans and act as essential carbon sinks.
Goa’s Beaches are Disappearing
Beach erosion in Goa is mainly driven by tsunamis, cyclones, tidal waves, and human activity. Rapid urbanization and development entail a growing number of buildings and other infrastructure, which have a high heat capacity. As a consequence, the heat gradient that arises between land and sea enhances the wind inland, increasing wave height and worsening coastal erosion.
Sand dunes, Goa’s main line of defence, have greatly disappeared as a direct result of erosion. This has reduced protection against wind, storm surges, and inundation, putting villages that were located behind sand dunes, such as Painguinim and Cavelosim, greatly at risk.
(Also Read: Impact Of Tourism On Goa)
Mangrove Restoration, Protection, and Conservation
Alongside the problem of beach erosion is the degradation of mangroves, also key to the buffering of waves and wind. Goa has faced a worrying decrease in mangrove cover over the last three decades, from 20,000 hectares in 1987 to 2,200 hectares in 2015. The degradation of this vital ecosystem has been induced by unregulated urban development, increased pollution, and tourism.
Mangroves are vital for reducing beach erosion for several reasons, mainly:
They act as buffers against waves, reducing the distance and velocity of inundation and protecting dikes and seawalls.
They enhance coastal accretion (accumulation of sediment) by producing and amassing organic matter, reducing coastal erosion in the long run.
They stimulate siltation since currents are reduced and more sediment can settle, creating a higher foreland in the long term and further reducing wave height.
Mangroves also provide breeding, nursing, and feeding grounds for fish, leading to an increase in fisheries that can sustain livelihoods through economic growth. Moreover, restoring and conserving this ecosystem can substantially benefit biodiversity and ecosystem services, replenishing coastal fauna and flora. Needless to say, communities will be less exposed to flooding and tsunami waves since they are prevented from living too close to the coast, overall reducing fatalities and property damage.
Considering nature-based solutions is important when evaluating the negative impacts of grey infrastructure. For instance, wave reflection from seawalls may result in scouring and subsequent lowering of the sand level, and erosion of adjacent, unprotected coastal areas may increase due to littoral drift. The ecological impacts of seawalls and their invasive construction mainly include disruption to biodiversity due to habitat loss, impacting an array of coastal animals including turtles and shorebirds. This leads to a longer-term reduction in animals’ population sizes, overall changing coastal fauna and flora, and habitat migration patterns.
(Also Read: A Brief History: Navi Mumbai’s Wetlands)
Obstacles That Need to be Overcome
Just like any other possible solution, however, there are certain barriers to implementation that need to be overcome.
First and foremost, there is still uncertainty regarding the efficiency and costs of restoring and conserving mangroves, mainly due to a lack of testing, monitoring, and reporting. There is also a lack of funding and information amongst actors and institutions, which leads to uncertainty about whether this solution should be public or privatized. Lastly, conflicts over land space due to different interests in land use make it hard for this solution to be planned and implemented.
To tackle these barriers, decision-making criteria when dealing with coastal erosion should be more expansive in nature. For instance, the goals of other policy sectors, e.g. public health and nature conservation, and the benefits this solution would provide to them should also be considered to make this intervention as efficient as possible. Additionally, more stakeholders and funding sources should be included to combine multiple interests and increase resources like knowledge. Lastly, this nature-based solution should be integrated with grey infrastructure to maximize effectiveness and compensate for the negative repercussions described above.
References
Department of Environment, Climate Change and Water NSW (2011). Draft guidelines for assessing the impacts of seawalls. DECCW NSW. https://www.environment.nsw.gov.au/resources/coasts/101043draftgdlnsseawalls.pdf
Dhargalkar, V. K. et al (n.d.). Mangroves of Goa. Forest Department Government of Goa, p. 84-91. https://www.forest.goa.gov.in/sites/default/files/ch7_man.pdf
Fernandes, P. (2012). ‘Concretized beaches hasten erosion’. The Times of India. https://timesofindia.indiatimes.com/city/goa/concretized-beaches-hasten-erosion/articleshow/11596064.cms
Goa Forest Department (n.d.). Mangroves in Goa. Goa Forest Department. https://www.forest.goa.gov.in/node/12
International Union for the Conservation of Nature (2016). Mangroves: Reducing the risk of disaster through nature-based solutions. IUCN. https://www.preventionweb.net/english/professional/multimedia/v.php?id=49020
NCSCM (n.d.). Coastal Sand Dunes of Goa. National Centre for Sustainable Coastal Management - Ministry of Environment, Forest and Climate Change in Chennai. http://www.dstegoa.gov.in/Sand%20dune%20report.pdf
NT Desk (2019). Goa’s Eroding Coast. The Navhind Times. https://www.navhindtimes.in/2019/05/22/opinions/editorial/goas-eroding-coast/
Spalding M. et al (2014). Mangroves for coastal defense - Guidelines for coastal managers & policy-makers. Wetlands International and The Nature Conservancy, p. 5-34. https://www.nature.org/media/oceansandcoasts/mangroves-for-coastal-defence.pdf
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