Four Washington residents whose car had plunged into the rain-swollen Rock Creek yesterday morning were rescued when U.S. Park police officers, a park maintenance crew and several motorists formed a human chain to pull them to safety.

The car in which the four victims were riding went out of control and plunged down an embankment into the creek, police said. It came to rest in five feet of water. The occupants climbed out of the car and one scrambled to the roof. The driver, Charles Rose, 39, of 1916 17th St. NW, held the other two next to the car until help arrived.

No one was seriously injured. Lonnie E. Poston, 83, of 1203 N St. NW, was treated for exposure at a hospital and released, park police said.

Police said that Rose was driving south on Beach Drive when he failed to negotiate a sharp turn and skidded into the creek. Park Police Officer John Farrell and maintenance men John Kelton and Frank Hart, who had been working nearby, arrived within minutes. They rescued Poston from the water, but the swift current prevented them from helping the other three, according to said Sgt. Terry Thompson, who supervised the rescue.

Thompson said Kelton then went about 30 feet upstream and floated down to the three remaining victims, tying a rope that was thrown to him to a car door. The chain of rescuers then helped Rose, his wife Doris, 40, and Marie Poston, 46 of 1001 Fifth St. SE, to the bank.

Four hours later, at about 11 a.m., a five-car chain reaction accident occurred a few blocks away at 16th and Allison streets NW, resulting in injuries to four persons including an 8-month-old child.

According to D.C. police, Henry Kannee, 81, of 4201 Cathedral Ave. NW, struck the car in front of him, triggering the pileup. Kannee was reported in critical condition at the Washington Hospital Center with serious head injuries and his wife Anna, 79, was listed in fair condition.

Esther Ketzlech, 60, of 900 Kersey Rd., Silver Spring, the driver of the car struck by Kannee, was taken to Howard University Hospital, where she refused treatment and requested to be transferred to Holy Cross Hospital, in Silver Spring. Her 8-month-old grandson Chad Schneider was admitted to Children's Hospital for observation, according to police.