Have you ever gone to your favorite beach and saw that it’s closed to swimmers because the water quality is not up to standards? 

There's a group of dedicated scientists in New Jersey who make that determination. A few summers ago, News 12 showed you how scientists wade out into the bays and lakes and test the water quality.

Another way they check for quality is by air.  

Six days a week, a plane takes off from Coyle Field in Burlington County, and on board are environmental scientists -- a skilled pilot and computer and data sensors recording what is seen.  

“We are looking for anything such as trash and debris floating in the water that could become a hazard for swimmers,” says Sheri Shifren, environmental scientist with the NJDEP. “We look for oil slicks, fish kills.”

Shifren is in charge of the state's beach monitoring program, which reports water quality levels from the ocean beaches to river swimming areas, like in Beachwood.  

“Mostly what we actually see is marine life, like dolphins, sea turtles, rays, whales,” says Shifren.

A sensor under the plane also monitors unwanted marine life – picking up levels of chlorophyll. Scientists know that high levels can spell trouble.  

Some beaches can be more prone to closures following heavy storms. The scientists say they don't see any problems heading into the extended holiday weekend.