The U.S. Geological Survey said Friday it can no longer monitor water resources in Puerto Rico because the territory's government owes it $2 million amid a worsening economic crisis.

The agency said it expects to stop operating up to 177 hydrologic stations by July 1. That would affect the ability to issue flood warnings and as well as the monitoring of water quality, aquifer levels and drinking water supplies.

The stations also are used for environmental research and provide data for water use, flood planning and climate change.

"It's a serious problem," Rafael Rodriguez, director of the USGS Caribbean-Florida Water Science Center, said in a phone interview. "The water quality network is being eliminated in its entirety."

Puerto Rico's Environmental Quality Board and 12 other local agencies are required by law to pay USGS 65 percent of the cost of operating the stations. However, the agencies have accumulated $2 million in debt in the past year, Rodriguez said.

He said the USGS has offered local officials a payment plan and proposals to lower the agencies' yearly contributions, but officials have not responded. A spokesperson for the Environmental Quality Board could not be immediately reached for comment.

More than 100 other stations would remain operational, but they are limited in scope and used exclusively by Puerto Rico's power agency and its water and sewer company, Rodriguez said.

It is the second time this week that Puerto Rico's debt has affected services. On Tuesday, the island's only active air ambulance company said it had suspended its services over a multimillion-dollar debt.

Puerto Rico has been mired in a decade-long economic slump and facing $70 billion in public debt that it is seeking to restructure.

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Danica Coto on Twitter: www.twitter.com/danicacoto