Ky Low-Flow and Mean Annual Flow Data

This is a vector data set consisting of lines representing streams in Kentucky. Each line segment is attributed with the 7-day 2-year low-flow frequency values, 7-day 10-year low-flow frequency values, and the mean annual streamflow values for the downstream end of that stream segment. For example, the "7-day 2-year low-flow" is the flow rate, averaged over seven days, that has a 50% chance (i.e. one out of every two years) of being exceeded in any year; the 10-year value has a 10% chance of being exceeded in any year (i.e. one out of every ten years). Low-flow values were calculated using the equations in the USGS Water-Resources Investigations Report 91-4097 "Low-Flow Characteristics of Kentucky Streams". Mean annual streamflow values were calculated using the equation in the USGS Water-Resources Investigations Report 02-4206 "Estimating Mean Annual Streamflow of Rural Streams in Kentucky". Users of the data should be aware of the limitations and accuracy of the equations as explained in those reports and summarized below (see "Constraints on accessing and using the data").本数据集为矢量数据集，包含表征肯塔基州境内溪流的线状要素。每个线段均附带三类属性：7天2年低流量频率值、7天10年低流量频率值，以及该溪流线段下游端点的多年平均径流量。例如，“7天2年低流量”指任意年份中，该7天平均径流量有50%的概率（即每两年出现一次）被超越；10年值则指任意年份中有10%的概率被超越（即每十年出现一次）。低流量值依据美国地质调查局（USGS）水资源调查报告91-4097《肯塔基州溪流低流量特征》中的公式计算得到。多年平均径流量则根据美国地质调查局（USGS）水资源调查报告02-4206《估算肯塔基州乡村溪流的多年平均径流量》中的公式计算。该数据的使用者应知悉上述报告中阐释、并总结于下文的公式局限性与精度情况（参见“数据获取与使用限制”）。