Flows In - Flows Out

Much of the poetic phenomena observed in nature are traceable to fundamental principles.

A water balance is an equation describing the flow of water in and out of a defined system much like an accountant's ledger of income minus expenses.

Catchment hydrology is the study of water in a drainage basin that uses a water balance to account for surpluses and deficits.

Water balance is based on the principle of continuity. Like a water budget, it considers:

Flows into a volume in a period of time minus the flows out of that volume in that time.

The Palisades of the West Gallatin, 1874
by William Henry Jackson

Water either accumulates, or is depleted, which follows from the law of conservation of mass.

No river can return to its source, yet all rivers must have a beginning.
— Native American Proverb

Fundamental laws abound in nature. Carl Sagan wrote, "The Earth spins because it did so as it was formed and there has been nothing to stop it since", which is an expression of Newton's laws of motion.

As mortal yet permanent passengers on Spaceship Earth, might we ever-so-slightly pay down whatever debt of gratitude we might have, at least during the conscious leg of our journey, by seeking to understand these phenomena in the context of fundamental principles?

"These woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep."
— Robert Frost

REFERENCES

• Shadows of Forgotten Ancestors, Carl Sagan.