Switzerland’s lakes reflect its craggy mountains and lap against its cities. Their blue surfaces are peaceful. And the waters are, seemingly, pristine.

But the placid exterior covers an explosive problem: Unspent military munitions lie deep below the waters, a fact that could eventually damage the lakes’ fragile ecosystems. So Switzerland is trying to crowdsource ideas for how to eventually extract the weapons if they begin contaminating the water.

The country has kicked off a competition with a cash prize of 50,000 Swiss francs, or about $58,000, to be shared by the three best proposals for removing ammunition that was dumped in the lakes over decades. But it must be done in an environmentally friendly and safe way.

There is no immediate need, the announcement stressed: Switzerland monitors the waters and officials said that a leak of pollutants from the munitions would be “against all expectations.”

“Regular monitoring of the lake water and sediments currently shows no negative effects from the dumped munitions,” Samanta Leiser, a spokeswoman for the Swiss federal office for defense procurement, wrote in an email, adding that the department “does not expect this to change.”

Rather, the country is trying to plan for a worst-case scenario about 20 years after an assessment showed that a cleanup of the explosives could “lead to massive sludge turbulence and high risks for the sensitive ecosystem,” the prize announcement explained.