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Lake Morphometry. Hydrology (residence time) Affects turbulence (sediment delivery) Stratification Productivity Resuspension. Morph. variables of interest. Catchment area Surface area Volume Depth (max and Mean) Lake “shape” or “form” Shoreline length or “development”.
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Lake Morphometry Hydrology (residence time) Affects turbulence (sediment delivery) Stratification Productivity Resuspension
Morph. variables of interest • Catchment area • Surface area • Volume • Depth (max and Mean) • Lake “shape” or “form” • Shoreline length or “development”
Catchment Area • Area of land that supplies water to a lake (not including surface area of lake itself) • Effects of catchment area?
Catchment Area • Larger catchment = more inputs, modified by: - Slope - ?????
Data from a map: • Surface area • Volume • Depth (max and Mean) • Lake “shape” or “form” • Shoreline length or “development”
Area • GIS software • NIH Image or Image J http://rsb.info.nih.gov/nih-image/ • Weight method (not recommended)
Volume • Construct a hypsographic curve • Area under curve = volume • Volume of truncated cones: V = h/3 * (A1 + A2 + (A1*A2)^0.5)
Mean and Max Depth • Mean depth z = V / A • Correlates with: - residence time (+) - productivity (-) - stratification (+) - sedimentation efficiency (+)
Morphometric indices of lakes: The Hypsographic curve • Kettle Lakes: small, deep, steep-sided • Scoured basins: variable, less steep • Mean Z / Zmax Area (m2) 0 Depth 25
Shoreline development • Shoreline development index (D= L/2(π*A)^0.5 • Circularity of basin