John WaltonFall, 2010
Salt cedar polygons.kmz
• Grows over shallow water table areas
• High amount of evapotranspiration
• Water balance component
• Qout of reach =
• Qinto reach + Groundwater inputs + Surface runoff
• -evaporation – transpiration - human use
• Solve water balance for groundwater input
• Assume steady state system where groundwater recharge equals discharge
• Take measured surface water flows and diversions• Estimate ET from Salt Cedar/Mesquite/cane
bosque area• Divide groundwater input by drainage basin area
to obtain large scale groundwater recharge rates• Answer: ~ 1 cm/year
• The potential difference between electrodes placed in the ground is measured. When an electric current is passed between two electrodes placed outside the measurement electrodes a potential difference is created.
• Deeper penetration of the electrical field occurs as the electrodes are spaced further apart.
• Interpretation of this data can be complex in some cases