<p>Old MacDonald had a farm. And on that farm, he had a pond. Old MacDonald (OMD) liked
spending a lot of time fishing in his pond. One day a friend told him that the fish will grow twice as big if the pond was twice as large. So, OMD decided to enlarge his pond from 2.5 acres to 5.0 acres. Because he spent most of his time fishing and not studying the hydrologic equation, something strange happened. Can you tell? Here are some numbers to crunch:</p>
<p>Qin = 130.8 cubic yards per hour</p>
<p>Qout = 97 m³/hr</p>
<p>Qseep = 0.0055 L/minute per m² of the lake area</p>
<p>P (precipitation) = 45 inches per year per m² of lake area (Account only for P falling directly
on the lake)</p>
<p>E (Evaporation) = 30 inches per year per m² of lake area (Account only for E directly from
the lake)</p>
<p>I (Irrigation) = 88 ft per day</p>
<p>h = 3 m (Assume that the lake describes a perfect circle).</p>
<p>Tasks/Questions:</p>
<ol>
<li>Scientists prefer SI units over the foot/inches/acres so commonly used in the U.S.
Please convert all non SI units into metric units (Hint: use meter and day units; convert
initial numbers accordingly)</li>
<li>What is the volume of the lake before and after OMD started digging?</li>
<li>Calculate the inflow and outflow from the lake before OMD enlarged it.</li>
<li>Calculate the inflow and outflow after the lake was enlarged.</li>
<li>Assume that before enlarging the lake, OMD diverted all inflows (including the amount of
rain falling onto the lake), how long would it take for the lake to drain completely?</li>
<li>After OMD drained the lake and enlarged it, what happened to his lake?</li>
<li>How could he have avoided this outcome?</li>
</ol>

CC BY-SA 4.0
2022-09-15T08:02:54.277Z
"Have you thoroughly searched for an answer before asking your question? Sharing your research helps everyone. Tell us what you found and why it didn’t meet your needs. This demonstrates that you’ve taken the time to try to help yourself, it saves us from reiterating obvious answers, and above all, it helps you get a more specific and relevant answer!" From the help center: https://earthscience.stackexchange.com/help/how-to-ask
Jean-Marie Prival
CC BY-SA 4.0
2022-09-15T08:04:42.580Z
So basically, nobody will do your homework for you. But if you show us what you've tried, and where you got stuck, we can help.
Jean-Marie Prival
<hydrology><water><lakes>
Hydrologic Mass Balance
thelegendofaang
# Hydrologic Mass Balance

(Asked by: username_0 on 2022-09-14)

Old MacDonald had a farm. And on that farm, he had a pond. Old MacDonald (OMD) liked
spending a lot of time fishing in his pond. One day a friend told him that the fish will grow twice as big if the pond was twice as large. So, OMD decided to enlarge his pond from 2.5 acres to 5.0 acres. Because he spent most of his time fishing and not studying the hydrologic equation, something strange happened. Can you tell? Here are some numbers to crunch:

Qin = 130.8 cubic yards per hour

Qout = 97 m³/hr

Qseep = 0.0055 L/minute per m² of the lake area

P (precipitation) = 45 inches per year per m² of lake area (Account only for P falling directly
on the lake)

E (Evaporation) = 30 inches per year per m² of lake area (Account only for E directly from
the lake)

I (Irrigation) = 88 ft per day

h = 3 m (Assume that the lake describes a perfect circle).

Tasks/Questions:

1. Scientists prefer SI units over the foot/inches/acres so commonly used in the U.S.
   Please convert all non SI units into metric units (Hint: use meter and day units; convert
   initial numbers accordingly)
2. What is the volume of the lake before and after OMD started digging?
3. Calculate the inflow and outflow from the lake before OMD enlarged it.
4. Calculate the inflow and outflow after the lake was enlarged.
5. Assume that before enlarging the lake, OMD diverted all inflows (including the amount of
   rain falling onto the lake), how long would it take for the lake to drain completely?
6. After OMD drained the lake and enlarged it, what happened to his lake?
7. How could he have avoided this outcome?

**Tags:** hydrology, water, lakes

> **Comments:**
> **username_1**: "Have you thoroughly searched for an answer before asking your question? Sharing your research helps everyone. Tell us what you found and why it didn’t meet your needs. This demonstrates that you’ve taken the time to try to help yourself, it saves us from reiterating obvious answers, and above all, it helps you get a more specific and relevant answer!" From the help center: https://earthscience.stackexchange.com/help/how-to-ask  
> **username_1**: So basically, nobody will do your homework for you. But if you show us what you've tried, and where you got stuck, we can help.  

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## 0 answers

