The Clean River Project: It’s a gold and blue November morning, the sun sparkling on the surface of the Merrimack River. In Methuen, the Clean River Project’s salvage team is preparing pontoon boats to go out on the water. Today’s mission: pull a submerged vehicle or two out of the river, where they have been decaying for years.

On a beautiful morning like this, it’s easy to forget that the Merrimack River hides secrets beneath its surface. Though there has been much progress over the past couple of decades — especially in dumping compliance by the companies that line the river from Lowell to Manchester, N.H. — old iron mill parts, electrical transformers, household appliances, illegally dumped cars and other detritus are currently decomposing in the silt at the bottom of the river. This pollution directly affects drinking water supplies in Lowell, Tewksbury, Lawrence and Methuen, among other cities and towns, and has caused the depletion and/or mutation of countless species of fish and wildlife.

The Clean River Project (CRP), founded by Rocky Morrison of Methuen, is dedicated to the cleaning and preservation of our nation’s rivers, lakes and streams, beginning here at home with the Merrimack. The team’s mission is to provide a safer water supply to the cities and towns that rely on it, and it is committed to encouraging environmental awareness through education. The work the team does in researching water quality and cleaning out the river is being taken seriously by the Environmental Protection Agency.

Team member Jon Bergeron, who grew up in Lawrence, provides the EPA with water samples and research results, and the CRP team helps the EPA locate dump sites along local waterways. CRP also has been called on by companies along the river to organize cleanup days. In this way, companies such as Siemens, Brox Industries, Doyle Lumber and Canobie Lake Park are helping to clean up the water many of us rely on.

Today, I’m boarding a pontoon boat with Bergeron and Jim McGowan, the U.S. marketing manager for Raymarine, to meet Morrison and his two main divers, Mike Nalen of Londonderry, N.H., and Todd Hammond of Haverhill, upriver in Dracut. They have previously identified two vehicles that are located near each other and prepared them for pullout. Other members of the team will also be there, along with a Coady’s tow truck that will do the actual winching. Some CRP boats are also fitted with winches that can be used occasionally, depending on the location of the vehicles.

Raymarine, a leading maker of marine electronics, has donated state-of-the-art sonar equipment to the Clean River Project. Though this sonar equipment was originally intended for use in fishing, Bergeron was able to modify some of it, and now interprets its video scans to locate vehicles and other debris covered by silt on the river bottom.

Today, the CRP team also includes Chris McNulty of Haverhill, Dennis Houlihan of Methuen and Nanci Carney of Salem, N.H., all of whom are longtime fishermen and naturalists and share an intense desire to pass along a cleaner world to their children.

The Clean River Project was founded in 2005 by Morrison and his wife, Paula. They could no longer sit by and watch rubbish and debris pile up on the once-pristine banks of the Merrimack. According to the Clean River Project’s website, when the Morrisons organized the first “scavenger hunt” with their fellow boaters, they removed from the shores of the river a total of 300 tires, two 30-yard dumpsters full of trash, furniture, car parts, appliances and more. The Merrimack River Scavenger Hunt has become an annual event. In 2007, CRP organized the first tire pullout day, resulting in 584 tires being removed from the river. When the water level was lowered to repair a dam that summer, they saw the cars — piled along the river bottom. A search located 23 illegally dumped vehicles. With the help of volunteers, those cars were removed from the Merrimack by the Massachusetts State Police as part of a training program.

A lot of work goes into preparing for a vehicle pullout. The team travels up and down the river by boat, mapping the bottom with sonar equipment, the results of which Bergeron interprets later. Meticulous notes are taken on location, position, direction and the rate of the river’s flow, and the vehicle is prepped by the divers for extraction. In pitch-black water, the divers have to locate each vehicle by feel. A buoy is attached to mark its location. The team then uses water jets to free the cars from the silt. If the vehicle is mostly intact, air bags can be inserted to cause it to rise. With vehicles that are too rusted and degraded to move, as many large parts as possible are retrieved, and the rest is left behind.

The cars being retrieved today are numbers 62 and 63. The pullouts go smoothly: Hammond attaches a tow hook to them and they are pulled onto the bank and righted. A Massachusetts state trooper is on hand to identify the cars by vehicle identification number or license plate and make sure there are no human remains inside. Both cars, one from Salem, N.H., and one from Massachusetts, had been reported stolen and are probably casualties of insurance fraud. Morrison inspects the insides for fish, and he finds some catfish, crayfish and a large eel, all of which are released safely back into the river. The doors are opened to allow water to drain, and Morrison triumphantly tags them with numbers 62 and 63 before they are winched onto the flatbed waiting on the highway. Every car pulled out of the river is a victory.