Gauge Record Hydrologic Statistics: Indicatorsfor Lake Classification

摘要

Surface water structures and associated active stage management and water use havealtered many lakes. Assessing the degree of alteration requires an indicator of hydrologicregime as a first step. Water level regime is an organizing principal of soil morphologyand the structure and function of wetland vegetative communities in lakes, marshes,ponds, and wet prairies. Although lake classifications have included a wide variety ofphysical and biological indicators for various purposes, none is based on hydrologicstatistics of water level regimes beyond frequency parameters and simple stage range.Statistical measures of exceedance and level change were derived from the gaugerecord for a sample of 135 lakes. These measures were used in a principal componentanalysis to derive independent indicators for lake classification. The first two principalcomponents accounted for 88% of the variance of six original variables and identifiedtwo indicators of hydrologic regimes: stage range (50%) and stage rise/fall symmetry(38%). These indicators of hydrologic regime classified north Florida lakes into eightgroups. The generally close correspondence of lake classes, based on hydrologic statisticindicators, to geomorphic and landscape classifications lends strong support to the gen-eral utility of this approach. This method will also be useful because the stage recordintegrates the inputs and outputs in lake water budgets, thereby providing insight intothese components when specific data about their magnitudes are otherwise lacking.