Question

Well A is driven down to an elevation of 200m above sea level and has a water column of 50m high. Well B is 2.5km away and is drilled to an elevation of 220m. The pressure at the bottom of well B is approx 100kPa. The hydraulic gradient between Well A and Well B is ____.

Answer 1

The hydraulic gradient between well A and well B is approximately -48900Pa.

Step-by-step explanation:

The hydraulic gradient between Well A and Well B can be calculated by subtracting the elevation difference between the two wells and the water column height from the pressure at the bottom of Well B.

Given:

• Elevation of Well A = 200m above sea level
• Water column height = 50m
• Elevation of Well B = 220m
• Pressure at the bottom of Well B = 100kPa

Step 1: Calculate the total elevation difference between the two wells:

Total elevation difference = Elevation of Well B - Elevation of Well A = 220m - 200m = 20m

Step 2: Subtract the water column height from the pressure at the bottom of Well B:

Hydraulic gradient = Pressure at the bottom of Well B - (Water column height x density of water x acceleration due to gravity) = 100kPa - (50m x 1000kg/m³ x 9.8m/s²) = 100kPa - 49000Pa = -48900Pa

The hydraulic gradient between Well A and Well B is approximately -48900Pa.