The Sagarmala Programme, launched by the Government of India to enhance the country’s logistics sector through port-led development, has sparked significant concern in Goa due to its proposed extensive dredging operations in the state’s rivers. While the project aims to boost maritime trade and connectivity, the environmental and socio-economic costs of dredging rivers like the Zuari, Mandovi, and Sal could outweigh any purported benefits for Goa.
This article leverages insights from aquatic science to highlight how the Sagarmala Project’s proposed dredging activities threaten Goa’s delicate aquaculture ecosystems, traditional fishing practices, and centuries-old sluice gate systems, while raising suspicions that the project prioritizes external interests, such as coal transportation, over local welfare.
The Ecological Impact of Dredging on Goa’s Rivers
Goa’s rivers, including the Zuari, Mandovi, and Sal, are vital to the state’s unique estuarine ecosystems, which support a rich biodiversity of fish, shrimp, crabs, clams and mangroves. These ecosystems are intricately linked to the Khazan system, a traditional agro-aquacultural practice that has sustained Goa’s communities for over 3,500 years.
The Khazan lands, formed over centuries , rely on a sophisticated network of dykes, canals, and sluice gates (locally called manos) to regulate tidal flows and maintain a delicate balance between saline and freshwater environments.
Dredging, a key component of the Sagarmala Project, involves removing sediment and debris from riverbeds to deepen navigation channels for larger vessels. While this may facilitate maritime transport, it disrupts the natural flow and sediment dynamics of rivers, with severe consequences for aquatic ecosystems:
1.Habitat Destruction and Biodiversity Loss:
Dredging disturbs benthic (bottom-dwelling) communities, which are critical to the food chain in estuarine ecosystems. Species like shrimp, crabs, and finfish (e.g., red snapper and pearlspot) rely on these habitats for spawning and feeding. The removal of sediment can destroy fish nurseries in the Khazan lands and along mangrove-lined riverbanks, leading to a decline in fish diversity and productivity.
A study on sluice gate impacts in Bangladesh showed that disruptions to water flow reduced fish catch and species diversity, a likely outcome in Goa if dredging alters tidal patterns.
2. Increased Salinity and Water Quality n
Dredging can deepen river channels, allowing greater intrusion of saline water from the sea, especially during high tides. This disrupts the delicate salinity balance maintained by the Khazan system’s sluice gates, which are designed to prevent excessive salt
water ingress into paddy fields and aquaculture areas.
Increased salinity can render soils infertile, as seen in areas like Neura and St. Cruz-Merces, where breached embankments have already transformed agricultural fields into mangrove forests due to prolonged saline exposure.
Additionally, dredging stirs up sediments, releasing pollutants and heavy metals into the water column, which can harm aquatic life and contaminate groundwater, further threatening both ecosystems and human health.
3. Disruption of Tidal Dynamics:
The Khazan system’s sluice gates operate in harmony with tidal cycles, opening to allow fish and shrimp to enter channels during high tides and closing to prevent flooding of agricultural fields. Dredging alters riverbed morphology, potentially changing tidal flows and undermining the gates’ functionality. This could lead to uncontrolled flooding or prolonged exposure to saline water, damaging both aquaculture and agriculture.
Threat to Traditional Fishing and the Khazan System
Goa’s traditional fishing communities, deeply tied to the Khazan lands, face significant risks from the Sagarmala Project’s dredging activities. The sluice gate fishing method, practiced on islands like Chorao. Diwar and St. Estevam along the Mandovi River, is a sustainable practice that ensures high yields while protecting fish and shrimp populations. Fisherfolk use bag nets (manxeche jale) at sluice gates during low tides to catch migrating species, a practice regulated by local comunidades to prevent overfishing.
Dredging threatens this system in several ways:
1. Reduced Fish Catches:
Alterations to riverbed depth and tidal flows can disrupt fish migration patterns, reducing the availability of species at sluice gates. Siltation of channels (poiems) and weed growth, already identified as problems in Khazan fishing, could worsen with dredging-induced sediment redistribution, further decreasing fish catches.
2. Economic Impacts on Fisherfolk:
Fishing rights at sluice gates are auctioned annually, sometimes fetching up to a lots of lakh, reflecting their economic importance. Disruptions to fish populations could lower catches, reducing the value of these auctions and threatening the livelihoods of marginal farmers and women who rely on inland fishing.
3. Erosion of Cultural Heritage:
The Khazan system is not just an economic asset but a cultural treasure, reflecting the ingenuity of Goa’s Gauda tribes and Portuguese-era planning. Its sluice gates and bunds, built with eco-friendly materials like mud, straw, and bamboo, are a testament to sustainable resource management. Dredging risks dismantling this heritage by destabilizing bunds and rendering sluice gates ineffective, potentially leading to the abandonment of Khazan lands for more profitable but ecologically harmful intensive aquaculture.
The Coal Transport Connection:
The Sagarmala Project’s focus on deepening Goa’s rivers raises suspicions about its true objectives, particularly the potential prioritization of coal transportation over local interests. Goa has been a hub for coal imports, with ports like Mormugao handling significant volumes for industrial use. The dredging of rivers like the Zuari and Mandovi could enable larger vessels to transport coal more efficiently, aligning with the project’s goal of enhancing port connectivity. However, this comes at a steep cost to Goa’s environment and communities:
1. Pollution from Coal Transport:
Coal transportation via rivers increases the risk of coal dust and oil spills, further polluting water bodies already burdened by untreated sewage and industrial discharges, as seen in the case of the Sal River. Such pollution exacerbates water quality issues, harming aquatic life and rendering water unsafe for fishing and agriculture.
2. Displacement of Local Priorities:
The Sagarmala Programme’s emphasis on port-led development, that appears to prioritize industrial and .may be tourism interests over traditional livelihoods.
The focus on coal transport could divert resources from maintaining Khazan infrastructure, such as repairing breached bunds or desilting channels, which are critical for local farmers and fisherfolk.
3.Lack of Local Benefits:
While the Sagarmala Programme claims to promote economic growth, its benefits for Goa’s coastal communities are questionable. There is little evidence that this project addresses the specific needs of traditional fisherfolk or Khazan farmers. Instead, the project’s infrastructure developments seem geared toward external industrial interests, with coal transport being a likely driver.
A Call for Sustainable Alternatives
The Sagarmala Project’s dredging operations in Goa’s rivers threaten to unravel centuries of ecological and cultural heritage embodied in the Khazan system. Aquatic science underscores the fragility of estuarine ecosystems, where disruptions to sediment, salinity, and tidal dynamics can have cascading effects on biodiversity, fisheries, and agriculture. Rather than prioritizing large-scale industrial projects like coal transport, Goa’s development should focus on sustainable practices that preserve its unique ecosystems and support local communities.
1. Strengthening Khazan Management:
Investments should prioritize the maintenance of sluice gates and bunds to prevent salinity intrusion and flooding, ensuring the continued viability of agriculture and aquaculture. Community-led initiatives, demonstrate the potential for revitalizing fallow Khazan lands.
2. Promoting Sustainable Aquaculture:
Low-cost, multispecies capture-based culture systems, as trialed by ICAR-CCARI, offer a model for enhancing coastal fish production without compromising ecosystems. These systems integrate species like red snapper, pearlspot, and green mussels, aligning with the Khazan’s traditional practices.
3. Rigorous Environmental Impact Assessments:
Any dredging must be preceded by comprehensive studies to assess its impact on aquatic ecosystems and traditional livelihoods. These assessments should involve local communities and prioritize their knowledge of the Khazan system.
4.Transparent Project Goals:
The government must clarify the role of coal transport in the Sagarmala Project and ensure that local environmental and economic priorities are not sidelined. Public consultations with fishing communities and Khazan farmers are essential to align the project with Goa’s needs.
Conclusion
The Sagarmala Project’s dredging activities in Goa’s rivers pose a significant threat to the state’s aquaculture ecosystems, traditional fishing practices, and the ingenious Khazan sluice gate system. Far from delivering benefits to local communities, the project risks prioritizing external industrial interests, such as coal transportation, at the expense of Goa’s environment and cultural heritage. By leveraging aquatic science, we see that the ecological and socio-economic costs of dredging far outweigh any short-term economic gains.
Goa’s future lies in preserving its sustainable traditions, not in sacrificing them for unsustainable development. It is imperative that policymakers reconsider the project’s approach, prioritizing the voices of local communities and the ecological wisdom embedded in systems like the Khazan. Only then can Goa safeguard its rivers, its fisheries, and its way of life for generations to come.
