It all came together yesterday: the sky was blue, the few clouds were white: it is shirt-sleeve warm but not Washington humid, and best of all it was a Sunday.

For those who did not simply want to take a walk, bide ride, cut the grass or play a little polo, there were festivities on the Southwest waterfront, a street fair of Pierce Mill after 2 1/2 years of renovation.

Along the waterfront, things got off to a slow for Mr. Christian and the crew of the Poozie Bear.

Paul Christain, Fleet Captain of the Capital Yacht CLub was supposed to have the 30-foot twin engine Owens in midchannel to lead a Parade of Boats, but he could not find the keys.

Christian, son David, and step-sons Bobby and John Topa, 7 and 10 hunted above and below decks as the rest of the fleet of 47 boats headed out into the channel between Hains Points and the new Southewest water-front.

One of the boys finally found the keys and the Poozie Bear with the Christian family got underway. When the boat reached Ft. Mcnair, Christian spun her about, and with two blasts of his air horn and thumbs up sign to the D.C. Firefighters, the parade got under way.

With the Firefighter shooting seven streams of Potomac River water straight into air, the fleet headed north up the channel behind the curtain of mist formed when the 12-mile-per-hour wind hit the fire boat jets.

The breeze was sufficient to move the topsail schooner Deliam smartly along as Daniel Montague, an Episcopal priest stationed on the Washington shore, blessed the fleet as it passed in review.

"You've got the hustle and bustle of the city, but right off the waterfront its peaceful and tranquil." said Federal Energy Administration official Christian explaining the lure of the river.

His wife, Mae replied with the word "kinship" when asked what she talked about the river and Poozie Bear. "It's like a small town down here." she said, squinting in the bright afternoon sunlight.

The small town atmosphere Mae Christian relishes on the waterfront also was much in evidence on Capitol Hill yesterday as Friendship House. the city's oldest settlement house held its annual "Market Day" on 7th Street SE in front of the Eastern Market.

The smell of barbecued chicken, Italian sausage and West Indian delicacies filled the air as thousands of persons, of seemingly every age and race, mingled like old friends and looked over the tables and displays of edible and inedible wares.

there were homebabed cookies, pies and cakes, several display of pottery, tables covered with bolts of cloth and several varieties of political literature.

Five-year-old Krisby Morton, of Potomac, was busy at a table where children were being helped to build their own toys.

Krisby did not have much to say, other than to confirm that the wedge-shaped block of wood he was fiddling with was a "racing car," but Norma Morton, his mother, said "I've been coming to this (fair) ever since it first started (about 10 years ago).

"My husband Banara, the area is home. Banara, who lives just a few blocks from the market, was standing in the middle of 7th Street playing a 60-year-ols hand organ.

"THe neighborhood always asks me to play," he aside, adding he bought his instrument, which bears the label, "G. Molinari & sons, BKlyn. N.Y., " from an old vaudeville performer.

Banara, a street musician and attorney for the Indian Claims Commission, said he was constantly asked "where my monkey is. I gus I'll have to get a monkey."

Things were quieter yesterday at Pierce Hill, the stone and wood grist mill Issaac and Abner Pierce opened for business on the shore of Rock Creek in 1820.

There were no tables of food or large crowds, as there were on the Hill and the waterfront. But the giant mill stone - still since the September, 1975, flood - was rambling around once again, spinning and spinning and turning corn kernels and grains of wheat to flour.

Park Ranger James Redmond, who works for the National Park Service, which runs the mill, explained it "gets flooded about a half-dozen times a year and the timbers were getting rotten."

At a cost of $17,000 the government replaced the timbers, replacing them with salt-treated beams, which, if they do rot, will take much longer to do so.

"We also replaced our pumps, " said Redmond, explaining that the mill's raceway no longer carriers the column of water needed to keep is pumped up from the creck to add to the flow that turns the creek to add to the flow that turns the water wheel.

Outside the mill, on the sun dappled lawn, small groups of strollers paused to watch a Potte throwing a pot, there to watch a trio of two dulcimer players and an authocharpist and a barkrshop quarter.

"It's great to have the crowds back here," said Redmond, surveying a beautiful spot on a beautiful day."