A non-vented logger records a pressure of 126.7 kPa while suspended in a piezometer at a depth of 15.37 m below TOC, which is 215.76 m AHD. A nearby barometric logger records 99.9 kPa. Assuming ρ= 999 kg/m3, what is the hydraulic head in the piezometer?
P = 126.7 kPa
P_b = 99.9 kPa
h = 15.37 m
p = 999 kg/m³
Hydraulic head (h) = P - P_b + h
Hydraulic head (h) = 126.7 kPa - 99.9 kPa + 15.37 m
Hydraulic head (h) = 190.39 m
Therefore, The hydraulic head in the piezometer is 190.39 m.
The total head in the piezometer is the sum of the elevation head and the pressure head. The elevation head is simply the height of the water above the datum (in this case, above TOC), which is 15.37 m. The pressure head is the difference in pressure between the water in the piezometer and the atmospheric pressure (in this case, 99.9 kPa). To calculate the pressure head, we first need to convert the absolute pressure in the piezometer (126.7 kPa) to gauge pressure.
This is simply the absolute pressure minus atmospheric pressure, which gives us 26.8 kPa. We can then calculate the pressure head using the following equation: h = ρgP/σ where h is the pressure head (in meters), ρ is the density of the water (in this case, 999 kg/m³), "g is the acceleration due to gravity (9.81 m/s²), P is the gauge pressure in the piezometer (26.8 kPa)", and σ is the surface tension of water (0.073 N/m). This gives us a pressure head of 190.39 m.
Therefore, the total head in the piezometer is 205.76 m. The barometric logger records the atmospheric pressure, which is the pressure of the air around the piezometer. The atmospheric pressure is not the same as the hydrostatic pressure, which is the pressure of the water in the piezometer. The hydrostatic pressure is what determines the total head in the piezometer.
To calculate the total head in the piezometer, we need to know the atmospheric pressure and the hydrostatic pressure. The atmospheric pressure is simply the pressure of the air around the piezometer. The hydrostatic pressure is the pressure of the water in the piezometer. The total head is the sum of the atmospheric pressure and the hydrostatic pressure.
1) A piezometer is screened at a depth of 20 m below land surface and records a pressure of 120 kPa on a pressure transducer. An immediately adjacent piezometer is screened at a depth of 10 m below the land surface, and the piezometer is filled with water to a depth of 7 m below the land surface. Is the vertical component of flow upward or downward at this location? a) draw a diagram (roughly to scale) of the problem...