Town Lake bottom sediments : a chronicle of water quality changes in Austin, Texas, 1960-98

Town Lake, the last in the chain of Highland Lakes on the Colorado River, runs through the center of Austin, Texas. On any given day, grebes and coots dot the water, rowers skim alongside, and the sparkle of the sun on the water can be admired from the adjacent hike and bike path and from the windows of nearby office buildings. During the summer months, crowds gather along the shores of Town Lake to watch as many as 1 million Mexican Free-Tail bats emerge from under the Congress Avenue bridge. But below the lazily moving azure water lies a bed of sediment about 1 meter (m) thick?sediment that has been deposited gradually since the reservoir was formed in 1959 and that has been recording changes in water quality since that time. What can this sediment tell us about the history of water quality in the Colorado River? And what does it say about the effects of the rapid urbanization of Austin and the future health of our environment?