I don't know of anyone who doesn't like riding the Staten Island Ferry: great views, fantastic photo-ops -- and it's free!

But now a study floated around by the city's Independent Budget Office has concluded that charging tourists $4 to ride the ferry would generate as much as $4.5 million a year in revenue. At least 60,000 passengers ride the ferry every day -- a number that's expected to grow because of new development in the borough.

This is a terrible idea. It should be allowed to sink to the bottom of the Hudson River.

As someone who lived in Staten Island for most of her life, I've spent years explaining to tourists who don't speak the languages I do that they don't have to buy tickets to get on the ferry.

Differentiating between residents and nonresidents may lead to initial chaos, but more important, it would create an untenable two-tier system. There are two ways this plan would supposedly work: Charge fares only on outbound Manhattan ferries, or include the ferry service in the MetroCard system.

Either way, it won't be easy. City transportation officials have said it would be unfeasible to charge a ferry fare that does not include Staten Islanders because the city would have to overcome federal rules that make it clear any changes must not lead to unfair disparities. Yeah, those pesky federal regulations.

But why even charge for what is arguably one of the city's most iconic attractions? It should remain free so more people can enjoy it.

Do we really not want people to visit Staten Island? Why not just build a giant wall around the borough? No wonder people, even lifelong NYC residents, always tell me they've never been there.

If the city really wants to make even more money from tourists, make it easy for people to visit the different attractions on Staten Island, including Richmond Town, the city's only historic village. You want to charge people to use public transportation on the island? Extend the subway from Bay Ridge to Staten Island. Expand the Staten Island Railway to serve the parts of the island that people actually visit.

The ferry is the only free way you can get to Staten Island. Let's keep it that way.

Rachel Figueroa-Levin tweets as @Jewyorican and @ElBloombito.