• Average level in late May for nation's second-largest freshwater lake is 13 feet
• 12,000-acre fire started in vegetation left dry by receding lake waters
• Okeechobee is primary backup reservoir for 5 million people in South Florida
A plant grows last month from the cracked surface of Canal M on Lake Okeechobee in West Palm Beach, Florida.
MIAMI, Florida (AP) -- Water levels in Florida's dried-out Lake Okeechobee dropped Wednesday to match a historic low set in 2001, while firefighters battled a blaze burning on part of the exposed lake bottom.
The South Florida Water Management District expected the water level to drop below the record of 8.97 feet (2.73 meters) on Thursday as the region's worst known drought continues.
The average water level this time of year in the second-largest freshwater lake in the United States should be around 13 feet (4 meters).
The 12,000-acre (4,856-hectare) fire started Monday in vegetation left dry after lake waters receded from its northwest rim, said Melissa Yunas, a spokeswoman for the Florida Division of Forestry.
The cause of the fire was unknown. It was about 50 percent contained, Yunas said.
Lake Okeechobee is the primary backup reservoir for 5 million people in South Florida during dry periods. Water management officials warn that the lower the lake levels drop, the less likely it is that summer rains will sufficiently refill the lake to meet water demands during the next dry season.
The continuing drought has forced stringent water restrictions on homes and businesses in 13 counties, and four coastal wells were closed to prevent saltwater contamination.
Officials have begun clearing 500,000 cubic yards (382,275 cubic meters) of rotted plant life and sediment from the southwest portion of the 730-square-mile (1,890-square-kilometer) lake to return its bottom to a more sandy base, improve water quality and restore wildlife habitat.
Copyright 2007 The Associated Press