(read below). 150-year record The covariation between δ18O in lake water and lake level in Mono Lake have been recorded over a 150-year time interval in Mono Lake. The δ18O record was compared to historic lake levels recorded by the USGS. The lake level and δ18O record were observed to have a strong correlation with minor offsets. Changes in δ18O of lake water were inversely correlated with lake level. This revealed six stages in lake level in the past 150 years: high stands at 1845, 1880, and 1915 as well as low stands at 1860, 1900, and 1933. The δ18O record compared well to the recorded precipitation and streamflow of Nevada City in California. Decreases in δ18O correlated well with increases in precipitation as well as increases in streamflow and vice versa. 10,000-year record A sediment core from Mono Lake reveals a 10,000 year record of carbonates (dated through ash beds). Here δ18O and δ13C did covary when observed through long time intervals of>5,000 years, whereas the correlation was not present during shorter time scales. It was found that the record revealed 5 periods of distinct lake conditions: 9.7 - 8.7 ka: Rising lake level. Decreasing δ18O and δ13C reflected an increased lake level. In fact, the lake level reached the Holocene High Stand. This high stand corresponded to a period of maximum effective moisture in the Great Basin. 8.7 - 6.5 ka: Dropping lake level. A sudden increase in δ18O and δ13C suggested that lake levels dropped. Following, weak correlation between δ18O and δ13C suggested that lake levels stabilized. 6.5 - 5.9 ka: Rising lake level. An increase in δ18O and δ13C correlated with a decrease in lake level. The lake level drop continued until the Holocene Low Stand at 5.9 ka, which corresponded to a period of minimum effective moisture in the Great Basin. 2 - 0.6 ka: Unconformity. The gap between 6 - 2 ka could be attributed to shallow lake conditions. In addition, sediment types observed in the core between 2 - 0.6 ka largely reflected shallow water conditions. During the Medieval Warm Period, which occurred from 0.9 - 0.7 ka, the lake level was around the same as today. In general, the period was dominated by a shallow, stable lake level with low covariance between δ18O and δ13C. 490 – 360 years ago: High, fluctuating lake levels. This period corresponded to the Little Ice Age.