Water Movements
Laminar and Turbulent Flow
Reynolds Number (Re)Laminar Re<2300Transient 2300<Re<4000Turbulent Re>4000
Turbulence is significant in:
• conduction of heat (eddy conduction)• diffusion of dissolved substances (eddy
diffusion)• viscosity (eddy viscosity)
Surface Waves
Deep Water Wave
Water Movement in a Surface Wave
Shallow Water Waves
Fetch
Lake Thunderbird
Whitecaps on Lake Michigan
Langmuir Circulation
Causes of Surface Currents
• Wind• Change in atmospheric pressure• Horizontal density gradients• Influx of water
Surface Currents in Lake Erie
Rip Current in Lake Erie
Currents in a Stratified Lake
Layers remain stable if the shearing force between them is low; Richardson number (Ri) remains higher than 0.25.
Coriolis Effect on water movement
Thermal Bars
Formation of a Seiche
Bimodal Seiche
Seiche on Lake Erie
Seiche traces from different parts of Lake Huron
Inflow and outflow in Galich Lake
Lake Sam Reyburn, TX
Richardson number = shearing force between layers
From Fernandez and Imberger (2006)
Table 7-1Velocity (cm/sec) Substrate Diameter range (mm)
3-20 Silt, mud, organic debris <0.02
20-40 Fine sand 0.1 - 0.3
40-60 Coarse sand to fine gravel 0.5 – 8
60-120 Small - large gravel 8 – 64
120-200 Large cobbles to boulders >128
Movement of Water in a Stream Channel
Run and Riffle
Standing Wave in Stream
Standing waves on the Colorado River in the Grand Canyon
Discharge and Gage Height
Rivers Reservoirs Natural LakesWater-level Fluctuations
Large, rapid, irregular; flooding
Large, irregular Small, stable
Inflow Runoff from surface irregular and seasonal; groundwater stable
From river and tributaries; internal flows complex
From low order streams, groundwater
Outflow Discharge irregular Highly irregular Stable; outflow shallow and groundwater
Flushing Rate Rapid, unidirectional, horizontal
Short, variable (weeks)
Long, years
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