Are Head Pressures in Two Different Wells Comparable?

[mathmanta]

Hiya,

Hope this is the right section - I didn't see a hydrology section.

I'm presenting this like a homework question, but its more for a conversation at my office.

There are two wells. The water in the two wells is the same (no density difference etc... - but that doesn't mean it's "fresh" water)

Well 1: This well is 480 ft deep and the static water level is 160 ft. The water bearing strata is at 480 ft. The casing is 6" I.D.

Well 2: This well is 720 Ft deep and the static water level is 560 ft. The water bearing strata is at 720 ft. The casing is 10" I.D.

What formula could I use for:

Q1:

Is the head pressure the same (within 10%) between the two wells?


And, is this true or false:

Q2:

If well 2 was 1100 ft deep, but the water bearing strata was still 720 Ft and static water level is 560 ft, the result does not change.

Ideas?

 

[mathmanta]

Hmm...

Well (pun), I guess for now I will simply calculate the weight of the water columns and see if they are the same.

 

[astrokreng]

I would approach this question by first considering the factors that affect head pressure in a well. Head pressure is determined by the weight of the water column above the point of measurement. In this case, the water bearing strata and the static water level are the key factors to consider.

To answer Q1, the head pressure in a well is not solely determined by the depth of the well. It also depends on the height of the water column above the point of measurement. In this case, well 2 has a deeper water column than well 1, so the head pressure in well 2 would be higher. However, the difference in head pressure between the two wells may not be significant, as the static water levels are relatively close. To calculate the exact head pressure, the formula would be:

Head Pressure = (Water Column Height) x (Water Density) x (Acceleration Due to Gravity)

In this case, the water density and acceleration due to gravity are constant, so the water column height is the only variable. The water column height for well 1 is 160 ft, and for well 2 it is 560 ft. Therefore, the head pressure in well 2 would be approximately 3.5 times higher than in well 1.

For Q2, the result would not change if well 2 was 1100 ft deep, as the water bearing strata and the static water level remain the same. The only difference would be a longer water column, resulting in a slightly higher head pressure. However, this change would likely be within the 10% margin specified in the question.

In summary, the head pressure in a well is determined by the height of the water column above the point of measurement, and the depth of the well is just one contributing factor. The head pressure in well 2 would be higher than well 1, and increasing the depth of well 2 would result in a slightly higher head pressure, but the overall result would not change significantly.