The last 30 years of urbanization around Lake Tahoe have caused as high a sedimentation rate as the clear-cut logging of the late 1800s that removed timber from more than 60 percent of the basin. That's the bad news from a recent report by graduate student Alan Heyvaert and his colleagues at the UC Davis Lake Tahoe Research Group. In better news, the study also revealed a period of recovery by the lake and basin in the early 1900s, as well as evidence that the famous Sierra Nevada lake responds quickly to changes in the basin environment. Under the direction of UC Davis professor Charles Goldman, researchers have been monitoring the alpine lake's health for nearly three decades. During that time, the population of the lake basin has increased tenfold, while the famed water clarity has been declining about one foot a year. Research efforts have been leading to practical solutions for environmental problems. For example, these early results from sediment core studies from the bottom of the lake suggest that plans to control erosion are on the right track, says co-author John Reuter, a UC Davis researcher and the director of the Lake Tahoe Interagency Monitoring Program. The sediment cores, analogous to tree rings, also provide a way of measuring the effectiveness of such efforts, Reuter says. The results were presented at a recent meeting of the American Society of Limnology and Oceanography.