The Supreme Court set a bad and far-reaching - precedent last week when justices let stand a lower-court decision that the Clean Water Act gives the federal government the right to regulate even shallow, wet-weather ponds on private land.

The court acted on the theory that seasonal, shallow ponds on private property may be used by migratory birds or endangered species and thus are subject to federal control.Under the ruling, federal regulation could be imposed even if the ponds resulted from holes dug for another purpose, contained only a few inches of water and had no water at all outside of the rainy season. That description might fit anyone's back yard. The possibilties are endless.

The justices refused to review a decision of the 9th U.S. Circuit Court of Appeals which found that the 1972 law - meant to help stop pollution in the nation's waters - extended to shallow, stand-alone artificial pits on a small tract of land near the San Francisco Bay.

The Leslie Salt Co., owner of the 153-acre strip of land, claims the Clean Water Act was enacted to protect oceans, ponds, streams, lakes and rivers, but is being misused when it is invoked to limit activity around inches-deep puddles that fill with water only when it rains.

The property originally was pastureland, but early this century was modified to make salt. Pits were dug for depositing calcium chloride, and large, shallow, water-tight basins were built for crystallizing salt. In 1959, salt production stopped, but the pits and basins remained.

In 1985, when Leslie Salt began digging a ditch and siltation pond to drain the land, the Army Corps of Engineers stopped them, invoking the Clean Water Act and claiming that Leslie Salt was discharging fill, technically a pollutant, into U.S. waters.

The Supreme Court's ruling in this case opens the doors for a disturbing chain reaction. The verdict could be used to halt activity on millions of acres of land - all because Washington wants to supervise shallow ponds on private property.