Cyclone shelters, embankments and shrimp ponds: ranking adaptation under a budget
A coastal block with 18,000 people has faced nine cyclones in 20 years. A 2.5 km earthen embankment protects 1,200 ha of paddy, but it breached twice, and soil salinity in the protected area has risen to 4 dS/m. About 300 ha of paddy land has been converted to brackish-water shrimp ponds. The block has one cyclone shelter built for 800 people, but it is 4 km from the most exposed village. The district has ₹8 crore for adaptation. Costed options are: raising the embankment to a higher crest for ₹4 crore; planting 200 ha of mangroves for ₹1.5 crore; a new shelter and approach road for ₹1.2 crore; household rainwater harvesting for 1,500 families for ₹0.9 crore; and an early-warning public address system for ₹0.4 crore. Shrimp farmers argue that ponds earn more than paddy.
1. Rank the five options and recommend a funded package within ₹8 crore. Justify the ranking on life-safety, reversibility, equity and maladaptation risk.
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Ranking criteria: life-safety first, then reversibility and equity, then maladaptation risk.
- Early warning (₹0.4 crore): low cost, reaches many people, saves lives, reversible and complements all other measures.
- New shelter and approach road (₹1.2 crore): the existing shelter is 4 km from the most exposed village; the approach road matters because flooding cuts access. High life-safety benefit.
- Mangroves (₹1.5 crore): reduce wave energy, trap sediment, support fisheries and can be restored. They take years to mature, so they complement, not replace, the embankment.
- Rainwater harvesting (₹0.9 crore): protects drinking water when salinity rises and is household-controlled.
- Embankment raising (₹4 crore): can protect paddy, but a higher crest without sluice gates, drainage and community maintenance can trap rainwater, increase waterlogging and fail again. It benefits landowners most.
Package: early warning ₹0.4 crore + shelter and road ₹1.2 crore + mangroves ₹1.5 crore + rainwater harvesting ₹0.9 crore = ₹4.0 crore, leaving ₹4.0 crore. Use ₹2.5 crore for embankment repair with sluice gates and a maintenance fund, and ₹1.5 crore for salinity-tolerant paddy, drainage and monitoring. Do not spend the entire budget on a higher embankment.
2. Which proposed or existing measures risk maladaptation, and how would you redesign them?
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Shrimp expansion is the clearest maladaptation. Brackish ponds raise soil and water salinity, can require pumping and feed, and may undermine the embankment through seepage and excavation. They benefit pond owners but degrade paddy land and drinking-water sources for others. Redesign: cap expansion, require setbacks from the embankment, manage saline effluent, and do not convert further paddy without community consent and a salinity assessment.
Embankment raising without drainage can trap monsoon rainwater, causing waterlogging and crop loss. Redesign with sluice gates, internal drainage, and a community maintenance agreement.
Deep tube wells for freshwater in a saline coastal aquifer can draw saline water inland. Redesign around rainwater harvesting and managed recharge.
A shelter without an all-weather approach road can be unusable during a cyclone. The road is part of the shelter.
Maladaptation is not only an engineering failure; it is a distributional choice that shifts risk to poorer users.
3. Define monitoring indicators for five years and explain how you would use them to adjust the package.
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Indicators: number of households reached by early warning and time from warning to evacuation; shelter occupancy and condition; road passability during monsoon; embankment breaches and repair status; mangrove survival and area; soil salinity in paddy plots; household rainwater storage and use; drinking-water salinity; shrimp-pond area; and crop yield.
Frequency: early-warning tests before each cyclone season; shelter and road inspections quarterly; embankment inspections before and after monsoon; mangrove survival annually; salinity and water quality twice a year; crop and pond area annually.
Use: if mangrove survival is below 60% after two years, change species or protect planting from grazing. If salinity continues to rise, tighten pond setbacks and expand rainwater harvesting. If the shelter is underused because the road floods, prioritise road raising. If embankment repairs are not maintained, shift funds from new construction to a maintenance contract with the panchayat.
Governance: publish a simple dashboard, include women, shrimp farmers and paddy farmers in the review, and hold an annual public adaptation review. Monitoring should trigger budget shifts, not just produce reports.