Poised precisely between the vast watersheds of the Rhine and the Danube, this alpine resort village well remembers the Americans who flocked here not so many years ago for the superb, sunny skiing available within a few yards of most everyone's doorstep.

The Americans who frequented Lech chose it over such better-known ski towns as St. Anton, St. Christoph or Innsbruck, in part because of Lech's easier informality and its emphasis on family-oriented pensions and hotels where apres ski is a pleasant diversion and not a holiday preoccupation.

Once, according to local tourist authorities, perhaps one in every five skiers here during the peak winter season spoke English like a native.

While the charming, casual air still exists here and the sun is as stunning as ever, the dollar's decline has swept Americans from local slopes as if by avalanche. Just 2 percent of all bookings here during 1977 were made by Americans and British - a direct result of the two countries' currency problems.

Yet hope springs anew in sunny Austrian hearts. "We have been getting an increasing number of inquiries from the states this season," says Hubert Schwarzler, director of tourism for Lech. "Maybe next year . . . maybe some are interested in the summer season here as well."

Meanwhile, others have come in increasing numbers, replacing the missing Yanks. Lech is not hurting. Vacationing Germans have always favored Austria as a place to get away from it all, and they now account for about 60 percent of all guests. Lech enjoys the added distinction of being a favorite ski center for Austrians themselves, who account for about 22 percent of the bookings.

Set in a stunning alpine valley 4,700-feet above sea level in the western region of Austria known as the Vorarlberg, the village has been known for its superior slopes ever since the turn of the century, when travelers began venturing here seasonally in numbers for the first time. The world-famed Arlberg Ski School was founded in nearby St. Anton in 1922, and now has more than 300 instructors. The Arlberg Method has spread through these Alpine resorts, acting like a magnet for vacationers who have the inclination - and the money - for first-rate instruction in the newest innovations of downhill skiing.

During the winter season, which peaks twice - during the month before Christmas and through February and March - all of the village's 6,000 guest beds are normally taken. The town center, with the usual expensive sports and clothing stores as well as souvenir and food shops, is jammed with people. But there are nearly three dozen ski lifts in the immediate area of Lech and Zurs, the closest large village, with a peak capacity of 35,000 persons per hour. Although from time to time we encountered some delays (in one case, 23 minutes to get aboard a cable car) for lifts right in Lech itself, we found the slopes farther away surprisingly free of lines.

Just about any kind of skiing is available, from gentle slopes for beginners to advanced mountainous trails high above the tree line. For the most part, the average intermediate skier who enjoys the sport in its season can easily find miles and miles of broad alpine slopes, challenging but safe mountain passages, and long downhill runs posing few tricky spots.

Accompanied by a ski instructor, or simply with friends found at the hotel or pension, it is possible to use the cable cars and chair lifts to go miles from Lech and then to ski back, an outing that can easily take all day, with time out for lunch at a restaurant in Zurs.

Fifty percent of the accommodations are available in small hotels and pensions, another 25 percent are in rental apartments and private homes leased by the season, and the final quarter, cheaper than the others, are beds in private homes. A rate brochure indicates the average cost of a room with bath per person per night, modified European plan (breakfast included), is an average of about $14 dollars per day. That figure - and any other dollar figures in this article - was computed on the basis of 15.35 Austrian schillings to the dollar, the general exchange rate obtainable at a bank in Austria last month.

Clearly, the larger hotels and more sumptuous pensions will cost substantially more. But ski tour packages, which account for considerable business from America, according to tourist director Schwarzler, could mean reductions in all costs.

With three children ages 5 through 10, a nanny who had never skied before and two intermediate skiers with miles of Vermont slopes behind us but badly out of practice, we faced the prospect of matching these varied levels with the right ski instructor. The Lech branch of the Arlberg School took care of everything. By the afternoon of the first full day, everyone was signed up and slotted into a comfortable level.

Two daily classes of two hours each per adult for six days cost $60; children under 12 cost $45. Classes varied in size from four to 15, which the instructor admitted was too high but a necessity in the peak season. Lift tickets cost $13 for 30 tickets. My wife and I found that a booklet apiece lasted a little more than a day. A seven-day pass costs $71 in the busy season and all lift fees drop by about a third after Christmas and New Year's.

Austrian cuisine makes up in quantity for whatever the highly attuned palate may sense is wanting in the way of culinary adventure at most restaurants and hotels. People burning calories on the slopes build appetites easily and are well satisfied with the likes of weiner schnitzel, pommes frittes, bean salads and strudels of various kinds all drift-deep mit schlag.

Our most extravagant outing, by horse-drawn sleigh through wonderful pine forests beneath a mystical night sky loaded with stars, was to a country inn near Lech famed for its beef fondue. This vast repast, including a bottle of dry red wine, and two rounds of milk for the children, cost $11 a person, including tip.

After six days of ski school and sun, we were all taking the chair lift to the top of a nearby mountain - even the 5-year-old - and getting down without difficulty and with much enjoyment. After weeks of dull gray skies, the children had arrived in Lech looking pasty-faced and drawn. We left with tans, and happy memories, sorry that there weren't more Americans with us on the slopes.

But as they say in Lech, maybe next year . . .