Tierra Verde and Costa Mar Dispute Water Rights as Dry Season Deepens

The dry season has come to the Río Esperanto, and with it, a bitter argument between Tierra Verde and Costa Mar over who owns the water. For three weeks, the Federal Hydroelectric Authority has been releasing less water from the dam at the regional border, citing Costa Mar's emergency request to maintain minimum flow for its eco-tourism operations downstream. Tierra Verde's smallholders, whose irrigation schemes depend on steady flow from the river, say they are being shut out of their rightful share. The dispute touches on a 1995 water-sharing accord that neither region has amended since the Federation's founding, and both now claim the other has breached it.

In the interior hills near Iguazú, farmer Miguel Díaz stood at the edge of his yerba mate plantation and pointed to the irrigation channel that had run full just two months ago. The water level has dropped a metre, and the flow has slowed to a trickle. His yield will suffer if rainfall does not return within weeks. "We are being told to accept rationing," he said, "while Costa Mar's hotels fill their pools." Across the region, smallholders are reporting similar anxiety. The Cooperative Council in San Vicente has called for an emergency meeting with the Federal Interior Minister to challenge what it calls an inequitable allocation.

Costa Mar's position is equally firm. The region's conservation authority argues that the hydroelectric dam's minimum environmental flow—the amount of water that must pass through daily to sustain the river's ecosystem and the tourism economy that depends on it—has been set too low by federal regulators. A prolonged drought, Costa Mar officials say, will expose that shortfall catastrophically. The region's dive operators and eco-lodge owners have submitted formal complaints to the Federal Hydroelectric Authority, warning that low river flow will damage the very natural assets that draw visitors and revenue.