©Jeffrey S. Juel 2013

Tide Gates and the Neolithic Revolution or

Tide Gates - The Answer to the Ultimate Question

of Life, the Universe, and Everything1

By Jeffrey S. Juel, PE (Civil Engineer)

Abstract. This paper presents a theory regarding the prehistoric shift from hunting and gathering to agriculture,

otherwise known as the Neolithic Revolution. I refer to this new theory as: The Enlightened Neolithic Engineer Theory.

Roughly 10,000 years ago a Homo sapiens with a clever idea and the power of persuasion envisioned a revolutionary

device known as a “tide gate”. The fabrication of a crude but effective culvert and tide gate along with the

construction of a small levee on a flood plain by a clan of hunter-gatherers - at the right place - were integral to a very

productive primordial Neolithic farm. The economic success of this farm led to larger and more farms, societal

organization, more food, more people, and, in time, ancient civilizations.

Keywords: Tide Gate; Agriculture; Hunting–gathering; Evolution; Neolithic Revolution;

Transition; Ultimate Question;

Anthropologists, archeologists, and economists have proposed a number of theories to explain why the

Neolithic Revolution began approximately 10,000 years ago. None of these theories are particularly

persuasive or compelling - or widely accepted. Civil Engineering can be thought of as the engineering of

the infrastructure of civilization. As a civil engineer, I have a perspective that is unorthodox compared to

the musings of anthropologists, archeologists, and economists. I also have expertise in a somewhat

obscure realm within engineering - specifically: flood control, tide gates, levees, and drainage.

A tide gate is a water control device that is used to drain soggy low-lying land that is located near a body

of water that is subject to tidal water level variations.2 A tide gate allows water to flow downstream

through a culvert during low tides while preventing water from flowing in the opposite direction during

floods and high tides. Tide gates are commonly used for the drainage of agricultural land on flood plains

adjoining estuaries. They have been used in many locations around the world – in some places for

thousands of years. They make agriculture possible in what would otherwise be water-logged soil that

can only support swamp or marsh vegetation.

1 This is a reference to The Hitchhiker’s Guide to the Galaxy by Douglas Adams

2 A tide gate located up-river from where significant tidal water level variations occur is what I refer to as a simply a “flap-gated culvert”.

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Photo of the new aluminum tide gate (left) and the old wooden tide gate (right) at the Chinook River during a low tide.

The tide gate to the right in the photo above is simply a rectangular slab made up of wooden timbers

with small concrete blocks attached near the bottom edge. The concrete blocks ballast the tide gate and

prevent it from floating during high tides. The gate is hanging by chains attached to the concrete

structure on which Highway 101 crosses the Chinook River in SW Washington State.

This photo illustrates that a functional tide gate can be very low-tech. A similar tide gate for use with a

small culvert could be made from a single monolithic rectangular-shaped slab of wood ballasted by

lashing an oblong stone near the bottom edge of the gate. Straps made from durable animal hide could

be used to hang a small tide gate - rather than chains.

A very primitive yet functional tide gate could have been produced using Stone Age materials: wood;

stone; and vines or animal hides - and Stone Age tools: a knife; an axe, a chisel; and an adz3. A tide gate

such as this in conjunction with a small earthen levee in the right place would have been invaluable for

instigating a Neolithic Revolution.

The Neolithic Revolution

The Neolithic Revolution was the most important event in the history of the world. This revolution

resulted in mankind’s transition from primitive nomadic hunter-gatherers to groups of people who

3 Archeological evidence shows that all of the tools listed here were in use prior to the Neolithic Revolution. Stone Age craftsmen made these tools using wood, bones, and flint or chert.

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relied primarily on the food that they grew for their sustenance. These people remained more-or-less in

one place, produced food4, proliferated, and ultimately organized into ancient civilizations.

The Neolithic Revolution is the key to virtually everything. Very few important human inventions or

achievements pre-date the Neolithic Revolution. Had the Neolithic Revolution not occurred, humanity

would likely have been stalled in the Stone Age indefinitely. Solving the riddle of what caused the

Neolithic Revolution to occur is essentially finding the answer to The Ultimate Question of Life, the

Universe, and Everything.

In modern times, levees (also known as sea dikes), culverts and flap gates / tide gates5 have been

instrumental in beginning agriculture and establishing outposts of civilization in a multitude of untamed

remote locations with extensive wetlands: Acadia Newfoundland in the 17th century; coastal South

Carolina in the 18th century; New Orleans beginning in 1726; and the San Joaquin River Delta of

California in the 1850’s.

Puget Sound in Washington State has a multitude of estuaries and pocket estuaries along its convoluted

shoreline. There are many examples of tide gates playing a vital role in farming on these estuaries by the

earliest pioneers in Western Washington: The Skagit River Estuary beginning in 1863; the Davis Farm on

Lopez Island around 1870; and Swan Lake on Whidbey Island around 1890 – just to name a few sites.

Most ancient civilizations began on the flood plains of large rivers. It is likely that levees, culverts, and

tide gates played an important role when humans began the agricultural revolution(s) which gave rise to

ancient civilizations.

Is it possible that the invention of tide gates, culverts, and levees was the very spark that ignited the

Neolithic Revolution?

Ancient Horticulture

Hominids living within the past one million years were omnivores. We could eat just about anything –

including many plants. Ancient humans learned by trial and error which plants were edible. They also

discovered that some plants had medicinal uses. They found a variety of uses for the seeds, fruits, roots,

and fibers from a number of the plants in their environment. Very primitive hominids undoubtedly had a

basic understanding of plant biology and it is reasonable to assume that at some point, hominids had

the good sense to distribute the seeds of useful plants.

Ancient hominids would obviously benefit from the propagation of beneficial plants and some effort

was likely made weeding, watering, and fertilizing these plants. In spite of man’s flirtation with

“farming” in the distant past, the Neolithic Revolution only occurred relatively recently. Anthropologists

and economists have pondered why the Neolithic Revolution happened at all. The consensus is that

4 And they used the excess food to generate wealth. 5 Without a tide gate or a flap gate, an earthen levee surrounding a low-lying area will result in a lake.

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farming required back-breaking labor - in comparison to hunting and gathering. Large scale farming was

more trouble than it was worth. Why would anyone want to even attempt it?

There are many theories that have been put forward to explain why the Neolithic Revolution began only

within the past 10,000 years. Most of these theories explain the revolution as a reaction to something

that changed in the environment: population pressure and a shortage of food; a surplus of food giving

people spare time; the extinction of big game and people needing to find something new to eat; new

plant species appearing; a warming period; a cooling period; a wet period; a dry period; a balmy period;

etc etc.

None of these theories is particularly compelling.

Seven Million Years of Human Evolution

It is rumored that the human race first appeared seven million years ago. There have been innumerable

ice ages, interglacial periods, warming and cooling periods, desertification, floods, plant and animal

extinctions, new species, and changes in sea levels during those seven million years. It seems

improbable that there was something unique and unprecedented about the environment since the end

of the most recent Ice Age that could explain why the Neolithic Revolution occurred when it did, and not

any earlier in human history.

By the end of the last Ice Age (13,000 years ago) the evolution of the human brain had progressed to

such a degree that when the climate warmed sufficiently, a particularly gifted individual in the right

place6 had the mental capacity, imagination, and communication skills to change their environment in a

profound and unprecedented way.

I propose that it wasn’t a change in the environment that caused the Neolithic Revolution; it was a

change in man. This change in man manifested itself in an Enlightened Neolithic Engineer roughly 10,000

years ago. This Enlightened Neolithic Engineer then changed the environment… and changed history.

6 The right place was not in Europe. The people there may have been smart enough - they just didn’t have the right plants, and/or a big warm fertile crescent and rivers like they did in Mesopotamia.

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It is remarkable7 to think that of the seven million years spanning the evolution of the human race,

99.8% of this period occurred prior to the Neolithic Revolution. The graphic below illustrates the vast

time span that preceded the earliest human civilization:

If the ancient pre-Neolithic hominids were simply at the mercy of the right conditions materializing so

that the Neolithic Revolution could begin, it is nothing short of miraculous that the conditions in place a

mere 10,000 years ago were unprecedented over the past seven million years of human history.

There has to be some other explanation…

I believe that environmental conditions were secondary to a more important factor:

The Neolithic Revolution began roughly 10,000 years ago, because

a human in Mesopotamia had sufficient intelligence to modify his

environment in a way that made agriculture possible without

requiring an excessive amount of effort.

I theorize that the invention of a crude tide gate was the technological breakthrough that made the

Neolithic Revolution possible. Tide gates (along with levees) changed the growing of beneficial plants

from a labor-intensive, hit-or-miss, marginal enterprise, into a very efficient and productive endeavor

that encouraged social organization.

7 … and possibly cause for suspicion.

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“I Have a Pipe Dream”

The necessary communication skills included a primitive verbal language; body language; hand-waving;

petroglyphs, fist shaking; monkey-see monkey-do; or some combination of these techniques.

Communication was vital since the construction of the culvert (a pipe), tide gate, and levee was much

too large of an endeavor to be attempted by a single person. The clan member/engineer who instigated

this plan would necessarily have been a respected leader in order to conscript the clan into doing

something that probably didn’t make much sense – at the time.8 He was able to get his clan to join him

in what must have seemed like a pipe-dream; the most consequential pipe-dream in history.

The warming period following the end of the most recent Ice Age corresponded with a growing human

population. Given the natural abundance of a typical estuary and the many opportunities for hunting

and gathering, a sizable fraction of humanity probably lived on or near an estuary. With a growing

population and a rising median IQ, the probability that someone somewhere would experience the

brainstorm to construct a culvert, tide gate, levee, and the primordial Neolithic farm would increase

over time. It was – so to speak - bound to happen.

Engineering the Neolithic Revolution

The mystery of the Neolithic Revolution - from an engineering and economics perspective – becomes:

1) What engineering breakthrough might a clever individual with Stone Age materials and tools

create that would set in motion an unstoppable Neolithic Revolution?

and:

2) How and where could land be exploited for agriculture using this engineering breakthrough with

minimal energy input?

I propose that the Neolithic Revolution can be attributed to:

sufficient evolution of the human brain

the period of warming following the most recent Ice Age

human ingenuity resulting in a crude but functional tide gate

a beneficial geometric progression (or two)

basic economics; and

a functional government

8 Rev. Martin Luther King Jr.’s I Have a Dream speech makes perfect sense: …I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self-evident: that all men are created equal." (“We hold these truths to be self-evident: that all men have evolved to be equal” just doesn’t sound right.)

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I believe that human ingenuity is the greatest force in the universe. Beneficial geometric progressions9

are also spectacularly powerful. A spark of ingenuity along with positive feedback loops and geometric

progressions made the Neolithic Revolution a spectacular success.

A culvert and tide gate made by an Enlightened Neolithic Engineer using stone-age tools at the right

place was the Ground Zero for the Neolithic Revolution. This ingenious device on a marshy estuarine

flood plain allowed food to be grown efficiently and very reliably without requiring back-breaking labor.

A Viable Stone-Age Culvert and Tide Gate

The culvert to which the primordial tide gate was

attached could have been a hollow log buried in and set

perpendicular to the levee. A much more practical culvert

could have been made by carving a log into a U-shaped

cross section, setting it in a trench, covering it with

rectangular-shaped flat stones, caulking the gaps

between the stones10, backfilling the trench, and then

constructing a levee atop the buried culvert.

Depending on the particulars of the area surrounding the levee11, an 18 inch diameter log 15 to 20 feet

long could provide adequate drainage for 5 to 10 acres of farmed land.

Stone Age people were capable of carving canoes from logs. Carving a log from end to end with the

cross-section shown would actually be considerably less work than carving a canoe. The log could be

crooked; the outside of the log would be left untouched; and the cavity inside the log could be very

roughly hewn.

A few pieces of quarried slate or some other locally available flat stones would provide a cover for the

culvert that would not rot. A large flat stone would be placed on the carved log square with the

outboard end of the log/culvert. The animal hide12 for the tide gate hinge would then be laid on the

stone and a second large stone placed on top of the first stone, thereby securing the hide/hinge

between the two stones.

9 An example of a geometric progression is a process that doubles, then doubles again, and again, and again, …. (1, 2, 4, 8, 16, 32…) 10 Plant fibers and stiff clay would make a viable caulk. 11 The particulars are: the site elevation relative to the tidal range, the rainfall intensity during the growing season, the soil permeability, and the evaporation rate. 12 The slab of wood could be covered by the animal skin that functioned as the hinge. This skin would also be an effective gasket that would reduce leakage past the flap gate.

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Side view of a tide gate on a log/culvert

The carved log and stones would then be buried within the levee with the ends of the log protruding

from the levee embankment. If the log came from a species of tree that resisted decomposition,, the log

could be expected to last for a decade or more.

Cypress wood is noted for its resistance to rotting. It grows in very wet conditions and it is believed to be

a native of ancient Mesopotamia. Seminole Indians in Florida used logs from large cypress trees for

canoe-making since the wood is soft and easy to carve. It is plausible that cypress was also the log of

choice for Neolithic culverts in the wetlands of Mesopotamia.

In time, the ancients likely experimented with materials that could be applied to the wood to slow the

rate of decay. For example, bitumen from an oil seep would have been a very effective wood treatment.

Natural oil seeps were known to exist in ancient Mesopotamia.

The flat stones could be re-used indefinitely. The leather hinge would require replacement at some

interval. Replacing the deteriorated tide gate components would be done periodically during unusually

low tides. The benefits afforded by this device for producing food would greatly outweigh the labor to

make it as well as the minor burden of maintaining the culvert and tide gate over time.

The tide gate depicted here is not based on any recovered artifacts that I am aware of. It is purely based

on my imagination. It is, technically possible. The Enlightened Neolithic Engineer responsible for the first

primordial tide gate may have been more clever and imaginative than I am. The first Stone Age tide gate

may have been a design that was even more simple and/or superior to what I came up with. As long as

they were functional, improved designs and more durable materials would be utilized on the second and

third (etc.) generation tide gates. The “tide gate technology” would evolve and improve with time as it

propagated within the estuary. This represents a geometric progression acting in conjunction with “the

survival of the fittest tide gate”.

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Some of the copies were better than others and some were spectacular failures13. Improvements were

attempted; some succeeded & some failed. A continually improving tide gate design evolved and

propagated over the centuries.

Human ingenuity, technological evolution, an economy of scale, social organization, property rights, a

geometric progression (or two), a vast and reasonably fertile flood plain, virtually unlimited fresh water,

efficient food production, and well-fed healthy humans breeding like rabbits combined to make the

Neolithic Revolution unstoppable. The wealth that was created by this revolution grew geometrically as

evidenced by the splendor of Sumer and the wonders of Ancient Egypt.

The Successful Primordial Neolithic Farm

My theory relies on the assumption that a functioning primordial tide gate resulted in a very

economically successful Neolithic farm. A case study in successful farming using levees and tide gates

exists on the Lower Skagit River delta floodplain in Washington State. Approximately 150 miles of levees

and over 100 tide gates on the Skagit River Delta are integral to a thriving farming community there.14

The viability of the first primordial Neolithic farm required a number of things:

Fertile soil

Cleared land (or a way to clear the land of native vegetation)

Adequate drainage (without the use of pumps)

Irrigation during dry periods (without the use of pumps)

A reasonable level of protection from floods during the growing season

A levee with a tide gate in the right place provides all of the above requirements.

13 The Golden Harvest GH-850 tide gate at Edison Slough is a great example of a spectacular failure. It just sat there stuck shut for two years. 14 In spite of the best efforts of environmentalists who would like to restore portions - or the entirety - of the Skagit River Delta to its 1850 condition.

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Fertile Soil – The wetlands and marshes within the estuaries of rivers are where substantial quantities of

organic material accumulate. The flow from the watershed upstream delivered the organic material to

the future primordial farm site. The wet conditions prevented the organic material from being lost due

to oxidation and decomposition. During the eons prior to the Neolithic Revolution, a very thick layer of

rich organic soil accumulated. If the primordial farm was located on a marsh along an estuary, it is likely

that the soil fertility would be excellent.

Cleared Land – If a site has fertile soil, and does not have excessive moisture, it is inevitable that it

already has existing vegetation - including old-growth trees and their massive stumps. If the area

surrounding the primordial farm was also forested, the Neolithic farmers would need to clear the land

they intended to plant as well as a considerable swath of land to the east, south15 and west of the site so

that the farm will not be shaded by the surrounding trees. Clearing forested land for the primordial

Neolithic farm would be back-breaking and very energy intensive - if not impossible.

If a naturally treeless marsh or shallow lake could be drained using levees and tide gates, clearing the

wetland would be possible with relatively minimal effort. If the climate had a sufficiently long dry

season, fire could be used to effortlessly remove the de-watered, dying and dry vegetation. With a little

luck, the seed bank of the site would be devoid of viable seeds. The majority of the seeds that survived

the fire would be for water-loving plants. They would not germinate and/or mature in the now well-

drained soil.

The site could be cleared and reasonably weed-free without requiring back-breaking labor.

Adequate Drainage – Shallow ditches and furrows directing water from the former wetland to a tide

gate will result in adequate drainage as long as the tide gate passes water on a regular basis. This will be

the case if the elevation of the site is at or above Mean Sea Level (MSL) and the water level downstream

from the tide gate is a few feet lower than the site on a regular basis. Digging shallow ditches and

furrows in soft marsh soil with a stone-age shovel carved from a wide flat stick is obviously feasible.

Whether or not this constitutes back-breaking work depends on the size of the shovel relative to the

person digging and how much soil they need to move.

Irrigation During Dry Periods – During dry periods the tide gate would be temporarily propped-open so

that it allows backflow during the high tide. This would deliver water to the fields when the elevation of

the fields was slightly lower than the tidal water level outboard of the tide gate.

Fresh water is less dense than salt water and it “floats” above a salt-water wedge at the mouth of the

river. If the tides and hydraulics of the nearby river are right, the salinity of the irrigation water will be

near zero.

If the site is very flat and the soil has sufficient permeability, sub-irrigation is an ideal and very

sustainable way to moisten the soil within the root zone of the plants being grown.

15 To the south in the Northern Hemisphere and to the north in the Southern Hemisphere.

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Protection from floods – If the levee is over-topped and the primordial farm is flooded during the

growing season; the crop could be a complete loss.16 This would be a major setback.

Surrounding the site with a levee of a given height will provide protection from floods lower than some

recurrence interval.17 A higher levee surrounding the primordial Neolithic farm would provide protection

from a 50-year flood.18 A levee with a more modest height would provide protection from, for example,

a 5-year flood.

The food initially produced by the primordial farm supplemented the food that was collected by hunting

and gathering. The original farmers could survive a catastrophic flood and a complete crop loss by falling

back on hunting and gathering until the next growing season’s harvest.

The engineering of primitive facilities for storing surplus grain likely happened soon after the Neolithic

Revolution was under way and the harvests produced excess food. Storage of crops would make the

occasional over-topping of the levee during a flood or the occasional catastrophic failure of the tide gate

tolerable. Levees providing protection from floods having a five-year recurrence interval would likely be

sufficient for year-to-year viability of a farming community.

A relatively high levee would require an unacceptable amount of labor – at first. In time, with a growing

population of workers available, a small levee could be raised. With a large population of workers, new

levees could be constructed to greater heights.

The flood stage vs. recurrence interval for the river at a given location is a function of the hydraulics of

the river, the contours of the valley, the hydrology of the river basin, and the magnitude of the

astronomical tides. The possibility of a concurrent low barometric pressure and/or storm surge resulting

from a severe weather system also factor into the flood stage vs. recurrence interval function.19

The ancient farmers would manage as best they could; setting the levee heights by observing evidence

of previous high water or by trial and error. If a levee is over-topped regularly – it obviously should be

raised.

16 The ideal crop for the earliest Neolithic farms in flood plains could tolerate some flooding. 17 This presumes that there is a culvert with a working tide gate in place preventing backflow through the culvert during floods. 18

A 50-year flood has a one in 50, or a 2% chance of being equaled or exceeded during a given growing season. 19 Calculating the flood stage vs. recurrence interval for a given site can be a major undertaking. (Deep Thought may be required.)

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A Plausible Primordial Neolithic Farm

A small (100 ft x 100 ft) primordial Neolithic demonstration farm (Beta Version 1.0) could have looked

something like this:

The shallow hand-dug furrows would be sloped to drain to the drainage ditch. The material excavated to

create the drainage ditch which surrounds the site would be used to construct the levee outboard of the

drainage ditch.

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The levee and tide gate would look like this during a high tide:

and like this during low tides:

The seepage coming from the farm would remove excess water the former wetland soils. During low

tides the culvert and tide gate would pass the water (seepage and runoff) that collected in the drainage

ditch to an existing natural ebb channel20 and on to the river.

If the tide gate is reasonably water-tight, when the groundwater level on the farm is lower than the

invert of the log culvert, any water residing in the low points of the drainage ditch will be stagnant

water. This minor detail (stagnant water) ultimately had very serious ramifications for the health of the

Neolithic farmers.

20 An ebb channel is a shallow natural meandering canal that carries water from the marsh during the falling ebb tides.

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Stagnant water in the ditch along a levee in Skagit County Washington

The Right Place

The right place for the hypothetical Neolithic farm is on a marsh within the estuary of a river or large

stream having year-round fresh water flow at a location with a reasonably long growing season. The

right place is where the river is subject to daily tidal variations on the order of at least a few feet. Ample

opportunities for hunting and gathering are common at estuaries. This would be advantageous since the

quantity and reliability of food from the small primordial concept/demonstration primordial farm

initially would only supplement the diet of the hunter/gatherer/farmers.

The photo used for the background in the graphic

on the preceding page is from an island at the

mouth of a large river in Mozambique. The photo

to the right shows the Island relative to the river

mouth and the coastline.

Any similar flat land along a tidally-influenced river

will suffice for the site of a hypothetical primordial

levee, tide gate, and Neolithic farm.

Tide Gates and the Neolithic Revolution 15 of 38

The tidal range is greatest at the mouth of a river and it generally decreases asymptotically with distance

upstream. If the tidal variations at a given location are excessive, the extreme high tides will require that

a relatively high levee be constructed. Since the volume of soil required for the construction of a levee

increases with the square of the height of the levee, constructing a high and massive levee during the

initial stages of the Neolithic Revolution would be labor-intensive and problematic.

Constructing a large levee is simply too much work for a small number of Neolithic farmers. However,

within a few centuries, constructing massive levees would not be a problem. To say that the ancient

Egyptian pyramids were monumental is an understatement.21 Constructing dozens of miles of canals,

ditches, and 10-20 foot tall levees would not be beyond the pale.

It is also important to note that excessively brackish water in the adjacent river would not be suitable for

irrigation. Fresh water must be present in the river if irrigation is required during dry periods.

Where a stream or river meets the sea, the lighter fresh water flowing downstream (weighing 62.5

lb/ft3) will float on the ebbing and flooding salt water coming from the sea (which weighs 65 lb/ft3). This

is what is known as a “salt water wedge”.

High flow from the river effectively pushes the saltwater wedge and the freshwater plume farther

downstream.22 The rising and falling tide causes the saltwater wedge to advance and retreat

respectively. A larger tidal range results in a saltwater wedge that precedes farther up-river during high

tides. Turbulent flow and diffusion cause the fresh and salt water to mix at the interface.

The magnitude of the tidal range decreases with increasing distance upstream from the mouth of the

river. At the “Right Place”, the pertinent variables resulted in fresh water with reasonably low salinity at

the tide gate at all times. The “Right Place” also had an elevation, tidal range, hydrology, and stream

flow characteristics that allowed for drainage during low tides and provided fresh water for irrigation

during high tides. The right place for the first Neolithic farm would have typical higher high tides23 that

21 The Great Pyramids are a testament to the wealth that resulted from the power of the geometric series that made the Neolithic Revolution a smashing success. 22 The large volume of flow from the Amazon River results in a freshwater plume that extends over one hundred miles out into the Atlantic Ocean. 23 Locations with semi-diurnal tides have two high tides every 25 hours. The higher of the two high tides is what is referred to as the higher high water.

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are no more than a foot or two higher than the ground level within the levee. This would allow the site

to be protected from high tides and from moderate floods by a relatively low levee. A few tides each

month would be high enough to allow irrigation by gravity through the temporarily propped-open tide

gate. The water drawn from the river would be skimmed off the top - above the saltwater wedge.

It is likely that there were innumerable “right places” on the planet following the most recent Ice Age. It

is also likely that over the span of a few centuries, there were dozens of primitive men and women who

had the ability to independently imagine a culvert, a tide gate, and the primordial Neolith Farm on a

flood plain.

The people living in the right places would occasionally experience destructive floods. In time, they

would have legends about floods and they might even build high mounds/structures that could be used

to escape floods. This was true for Sumer as well as other ancient civilizations.

Irrigation Trouble

During droughts, the Neolithic farmers would have a problem to solve: “The plants are wilting, they

need water. How can we get some of the water (but not too much water) from the river onto our

primordial farm?”

Water does not flow uphill and Archimedes’ screw probably had not yet been invented when the

primordial Neolithic farm was constructed. If the plants wither and die, the revolution is a bust.

The solution is obvious: Prop the flap gate partially open so that water backflows through the culvert

during a high tide and fills the ditches and the furrows. The trouble with this idea is that the volume of

water that will pass through a given tide gate opening varies depending on how high the high tide is. Too

much water will drown the plants.

The elevation of the high tide varies gradually from one day to the next. It waxes and wanes with the

phases of the moon. The Neolithic farmers would appreciate this and would select the right day to prop

the tide gate open to allow irrigation without flooding their fields.

As long as the high tide is slightly lower than elevation of the farm, the backflow through the partially

cracked open tide gate and culvert will not flood the field – it will simply fill the drainage ditch

surrounding the farm. The water in the filled-ditch would travel up the furrows and very effectively raise

the groundwater level of the field.

Sub-irrigation

The fine-grained soils of the estuary at the hypothetical Neolithic farm likely would have supported

effective sub-irrigation. Groundwater rises above the hydrostatic level due to the capillary action of

water within the voids between the soil particles. This moist soil lying immediately above the static

Tide Gates and the Neolithic Revolution 17 of 38

water level (the phreatic surface) is known as the “capillary fringe”. The capillary

fringe can extend for a foot or more above the static water level. By impounding

water in the drainage ditch at the appropriate elevation, the roots of the plants

being grown will be within the capillary fringe.

Sub-irrigation has a number of benefits over the irrigation systems that are

typically used in modern agriculture:

Sub-irrigation significantly reduces the amount of evaporation that

occurs compared to overhead sprinklers. Less water is needed and this

reduces the quantity of salts left behind after the majority of the water

evaporates.

A higher groundwater level reduces land subsidence by slowing the

decomposition of the organic material in the soil. A falling groundwater

level causes the soil column to consolidate and also exposes the organic

material in the soil to aerobic decomposition.

There is a location in the San Joaquin River Valley where the land

has subsided by more than 28 feet due to lowered groundwater

levels. Farming in the San Joaquin valley only began in 1850.

Clearly this is not sustainable farming.

If the capillary fringe reaches the plant’s root zone but falls short of the

surface of the soil, many of the weed seeds in the soil will be unable to

germinate successfully. Less weeding reduces the labor required to

produce food on the primordial farm.

Sub-irrigation results in quasi-sustainable farming. The Neolithic farms in Ancient

Mesopotamia would have been fertile and productive for centuries – but not

indefinitely.

What to Plant?

The region near the right place had edible plants that were easily propagated and could be stored for

consumption months after harvest. Some sort of grain would be ideal. The right place had adequate

temperatures and a sufficiently long growing season for these plants.

Some plants are easier to grow than others. For this hypothesis, I assume that the labor associated with

sowing, tending and reaping the crop grown on the primordial farm was an order of magnitude less than

the labor associated with constructing and maintaining the levee, drainage ditches, culverts and tide

gates. This is probably true for wheat and barley. Sowing the seeds is very straight-forward. After the

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seeds have been sown they would harvest any birds that come to feed on the seeds. If the soil becomes

dry, watering is effortless. In a few months, the clan harvests the grain.

As the population grew, the increase in available manpower allowed the cultivation of crops that were

more labor-intensive – such as fruits. There was no labor shortage in Ancient Mesopotamia shortly after

the Neolithic Revolution was under way. In time, the domestication of draft animals and the invention of

the plow would carry the revolution to an even greater heights.

Economics

Reasonably fertile soil, a non-viable native seed-bank24, gravity flow for drainage, and gravity flow for

irrigation combined to minimize the effort required to grow plants, while maximizing the probability of

success. If a low-maintenance crop is planted and a bountiful harvest results, the benefit would greatly

outweigh the labor cost.

On the other hand, the initial labor investment associated with carving a culvert, collecting flat stones,

assembling the tide gate, digging the ditch, and constructing a two-foot high levee around the site is not

trivial. If the levee, culvert, and tide gate had a reasonably long useful life, the sweat equity would be

paid back many times over. Within a few years, the economics of this endeavor were undeniable.

The labor expended preparing the soil, sowing the seeds, battling weeds, driving off (or better yet -

harvesting) grazing wildlife25, watering the plants, and harvesting the crop would vary from one location

to the next. It would also be a function of the crop being grown. Over time, the crops that were grown

would become “domesticated” with improved properties over their wild ancestors. The invention of

various labor-saving devices such as hoes26, hand ards, flint-bladed sickles, and – in time - plows pulled

by domesticated animals, would also increase production.

The economics were good to begin with and they only got better as the revolution progressed.

Property Rights and the Tragedy of the Commons

The concept of an individual “owning property” was foreign to Stone Age man. In the absence of private

property, economic development is hamstrung by the well-documented phenomenon known as the

Tragedy of the Commons. No man’s land – “the Commons” - are exploited and then neglected. In

contrast, the primordial Neolithic farm would be protected, nurtured and improved by the clan that

created it.

24 Virtually all of the seeds in the seed bank will be from the original marsh plants. 25

The farmers will also need to drive off individuals from the other clans who attempt to help themselves to the crops. Cannibalistic Neolithic farmers might actually “welcome” the visitors… 26 The Egyptians had a hoe called a mr.

Tide Gates and the Neolithic Revolution 19 of 38

The primordial Neolithic Farm, surrounded by a levee and ditch, would be intrinsically like a parcel of

land owned by the clan (or clans) that dug the ditch and built the levee. Plants growing on a plot of

ground with no associated infrastructure and with a nebulous border would be up-for-grabs by

comparison.

Economists believe that prior to the Neolithic Revolution, acquiring food via hunting and gathering was

far easier than farming.27 After the first Neolithic farm began producing food, by a large margin the most

economical way to acquire nourishment would be to help oneself to the food being grown on the

neighboring clan’s farm – Neolithic Obamunism.

Neolithic Obamunism created a demand for “NO TRESSPASSING” signs. Cuneiform writing did not yet

exist and this was compounded by the fact that if the local Obamunists28 weren’t smart enough to make

their own levees, tide gates, and farms, they probably also were not smart enough to read.

Ten thousand years ago (as well as today), a severed human head set

on a pike would be an unambiguous “NO TRESSPASSING” sign.

If a group of Obamunists elected to ignore (or did not understand) the

“NO TRESSPASSING” signs, they would soon discover that a farm

surrounded by a ditch, levee, and an expansive marsh is rather difficult

to raid. Around the time that the crops were ready to harvest, the

marsh plants would be mature and eight feet tall. Finding the farm in

an expansive field of tall reeds would be challenging. The Obamunists

would be slogging about, pushing their way through the reeds on a

muddy, gooey mire.

When they were within about 100 feet of the farm, the farmers who

were hard at work on the fields would hear them coming due to the

sloshing in the mud and rustling of the reeds.

From a foot path atop the levee, the Neolithic farmers could launch

scores of arrows towards the sound of the slowly approaching, then

frantically retreating Obamunists. Problem solved. The farmers would

now have something to go with their veggies and they’d also have raw

materials for making more “NO TRESSPASSING” signs.

The clans that consolidated and enlarged the extent of their Neolithic farm would have a numerical

superiority over the surrounding clans. As their population grew, defending the farm became

27

Note that most economists (and many engineers for that matter) have no idea what a tide gate is. 28 If you find the term “Obamunists” offensive, cross-out “Obamunists” and write-in a more palatable term. You will also want to change “Neolithic farmers” to “Neolithic Robber Barons”. Whatever…

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progressively easier. As the revolution progressed, Obamunism was left on the midden of history29 - at

least for a few millennia.

It should be obvious to any rational person that private property was vitally important for the Neolithic

Revolution and the advancement of civilization.30

Thoughtful engineering, individual initiative, private property and the Neolithic Revolution caused an

exponential increase in food production. This did more to alleviate hunger than the best laid plans of

every Marxist and community organizer in history.

Mesopotamia – Ground Zero?

It is widely accepted that the actual Neolithic

Revolution began in Mesopotamia31 on the

floodplains lying along and between the Tigris

and Euphrates Rivers in what is present day

southern Iraq.

Lower Mesopotamia - “The Cradle of

Civilization” - is a remarkably flat flood plain

lying between the city of Baghdad (in the center

of present day Iraq) and the head of the Persian

Gulf where the Tigris and Euphrates discharge

into this tidally-influenced body of water.

Prior to the Neolithic Revolution, the natural

landscape of ancient Mesopotamia was an ever-

changing collection of active river channels,

relict channels, lakes, marshes and swamps. 32 Where the marshes and swamps met the sea, the salinity

could be quite high. If the marsh did not receive fresh water from the north, the high evaporation rate in

the arid climate would concentrate the salts from the sea water that would flood the marsh during

extreme high tides.

Due to the immense quantities of silt that are carried and deposited by the rivers, the delta of the Tigris

and Euphrates Rivers today looks nothing like it did in antiquity. The rivers have shifted their beds and

created new channels countless times. A large area of the gulf has undoubtedly been filled-in by the

tens of millions of cubic meters of sediment that are carried by the rivers and deposited on the delta

29 "... freedom and democracy will leave Marxism and Leninism on the ash heap of history." – Ronald Reagan, June 8, 1982. 30 Sorry Karl. 31

Mesopotamia literally means “land between rivers”. 32 For an excellent reference book discussing the conditions in Ancient Mesopotamia, see Mesopotamian Civilization: The Material Foundations by Daniel T. Potts

Tide Gates and the Neolithic Revolution 21 of 38

each year. Land subsidence and changes in sea level have also affected the landscape over the past

10,000 years.

The gradients of the lower reaches of the Tigris and Euphrates rivers are remarkably flat. Downstream of

Basra, the rivers only fall about 13 cm per kilometer. The gradients of the lower reaches of the rivers

were probably only marginally steeper in antiquity. Rivers with flat slopes create their own levees.

During moderate floods and/or high tides, the river overflows its banks and the coarse-grained sediment

in the river drops from suspension on the banks of the river. In time, the river channel effectively

becomes perched above the surrounding flood plain with natural levees on each side. Large shallow

lakes are created when the river breaches the levee and floods the lower areas outboard of the levee.

The tidal range at the NW end of the Persian Gulf is on the order of 10 feet. The tidal range along with

the shallow gradient of the rivers suggests that daily tidal variations of at least a few feet were likely on

the main channels of the rivers for a distance of dozens of miles upstream from the river mouths. At the

present time the zone of tidal effect for both the Tigris and Euphrates extends to a point upstream from

the modern city of Basra, which is located nearly 70 miles from the Gulf.

The ancient Sumerian city of Eridu (founded ca. 5400 BC) is believed to be the earliest city in southern

Mesopotamia and the oldest city in the world. Note that this city was founded adjacent to a former

(now abandoned) channel of the Euphrates River not far from the Persian Gulf. The location suggests

that the earliest successful large-scale agriculture in Mesopotamia happened within a few miles of the

mouth of the Euphrates River. The tidal fluctuations there would make both drainage and irrigation

possible with a simple tide gate. By being on the main river channel, the volume of fresh water was

sufficient to prevent the salt water wedge from extending this far inland.

The Neolithic Farmers had tides without salt water.

The conventional wisdom is that 10,000 years ago wild wheat and barley grew in the Fertile Crescent.

The climate was in a state of flux after the most recent ice age, and at some point the climate was

perfect for growing grain. Gathering grain became much easier than hunting so people became farmers.

There are problems with the conventional wisdom:

1) What happened when they experienced a drought? (Answer – chaos and cannibalism)

2) Why would this cause people to organize into complex societies?

By farming on the flood plain and using river water and tidal variations to irrigate their fields, Neolithic

farmers would not be affected by droughts. As long as the river did not dry-up, they would be alright. A

dry sunny climate with reliable irrigation is actually the ideal condition for farming.

Collecting and eating wild wheat and barley would not motivate people to organize into larger

communities, whereas building and maintaining levees motivated people to organize and work together

to make the levees.

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I am not aware of any conclusive archeological evidence that supports my theory. Given the

environment in which they operated, remains of the earliest ancient tide gates would not be expected

to survive the ravages of time. Flood plains and wetlands are very dynamic. It would be miraculous if

evidence of the earliest human habitation on a flood plain survived through modern times. Flood waters

from extreme events eventually swept away any evidence of the primordial farm on a flood plain –

including the first crude tide gates. Artifacts associated with the very earliest use of tide gates for

agriculture had little chance of surviving to modern times, hence determining when and where Ground

Zero was may never be known.

The consensus among archeologists is that the Neolithic Revolution began in Mesopotamia and spread

from there to The Nile, The Ganges, and other river systems. In my opinion, this is purely conjecture. It is

difficult to imagine a person from Mesopotamia travelling to The Ganges River and directing the locals

there on how to construct a tide gate. There is a distance problem and a language barrier.

I speculate that the innovation described herein happened independently and more or less

concurrently33 in a number of locations. How quickly it was perfected and propagated varied from place

to place. Mesopotamia may simply have been the location where conditions were most favorable and

where the local political machine was not incompetent and/or corrupt. The revolution progressed

quickly, and within just a few centuries the Mesopotamians were well on their way to becoming an

advanced ancient civilization.

Many other ancient civilizations also arose on flood plains: Ancient Egyptians along the Nile River; The

Harappan Civilization in the Indus River Basin (Pakistan); and the Yellow River (Huang He) Civilization in

China. There is also evidence that the Mayans grew the food for their burgeoning population using the

wetlands in the surrounding countryside. Levees and tide gates would have been instrumental in the

rise of all of these ancient civilizations. The fact that so many important ancient civilizations arose on

flood plains suggests that my theory is plausible - to say the least.

Social Organization and Neolithic Farming

The advent of Neolithic farming on flood plains within levees resulted in an irresistible impetus for social

organization.

A geometry lesson:

Imagine a square-shaped primordial Neolithic Farm. The perimeter of a square with each side measuring

“s” is 4s. The area of this square is s2.

33 Multiple Stone Age inventors in different locations could have come up with viable tide gate designs within the span of a few thousand years of each other.

Tide Gates and the Neolithic Revolution 23 of 38

The food produced on the farm is directly proportional to the area lying within the square. If the size of

the square is doubled, the length of the levees and ditches that must be constructed doubles, whereas

the area and thus the amount of food produced, is quadrupled.

The graphic below illustrates this effect.

This geometric property had a remarkable effect on what transpired in the decades immediately after

the first primordial Neolithic farm began to produce food.

It is likely that agriculture was practiced to some degree prior to the first primordial levee and tide gate -

but it was, by comparison, a somewhat trivial and frustrating enterprise. The probability of success was

marginal and the benefits did not consistently outweigh the labor costs. To add insult to injury, the clan

that enjoyed the harvest was not necessarily the clan that cleared the land, planted the seeds, and

weeded and watered the plants34. More important for the Neolithic Revolution was the fact that prior to

levee building, there was nothing about the enterprise that motivated independent clans to cooperate

and consolidate.

When constructing levees to protect farmland from floods, it is much more efficient to protect a single

large area rather than a number of discrete smaller areas. The economic ramifications of this fact are as

vital as the invention of the tide gate itself.

For example: imagine that a hypothetical river flood plain is populated by 1,000 Neolithic farmers

organized into 50 clans with 20 adult individuals in each clan. Assume that when they are not busy

hunting and gathering for subsistence, or feuding, each clan is capable of constructing and maintaining

1,000 lineal feet of levee and the affiliated drainage ditch (20 individuals x 50 lineal feet of levee and

ditch per individual = 1,000 LF).

One thousand lineal feet of levee will surround a square farm having an area of (

)

= 62,500 ft2 or

roughly 1.5 acres. That works out to 3,125 SF of garden space per adult. A 100 ft x 30 ft garden would

34 Stone Age Obamunism.

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not produce enough food for a person to live on for the entire year, but it would significantly

supplement the food acquired by hunting and gathering.

If the 50 clans on this hypothetical flood plain construct and maintain their own separate levees

surrounding isolated 1.5 acre farms, the cumulative area is 3,125,000 ft2 (50 farms x 62,500 ft2 per

farm).

If the 50 clans jointly construct and maintain a single levee around a very large farm, the total length of

the levee will be 50,000 feet (50 clans x 1,000 ft of levee per clan). This levee will protect a square

Neolithic farm having a total area of (

)

= 156,250,000 ft2 or 3,587 acres. This represents a 50-fold

increase in food production (156,250,000 ft2/ 3,125,000 ft2).35 The amount of food produced per person

is 50 times what it would be if the clans operate discrete farms independently.

The graphic below shows the relative size of 50 discrete levees vs. one large area surrounded by a single

levee. The sum of the perimeters of all of the small farms is equal to the perimeter of the large farm.

The economy of scale is readily apparent. If 100 clans consolidate and construct a single square levee,

the area under cultivation per person increases by a factor of 100. If a single clan’s Beta version 1.0

Neolithic farm was profitable, the consolidated farm produced by the 100 clans together would produce

an incredible surplus of food.

Actual levees meander along waterways and long levee surrounding a single area would effectively be

like putting all your eggs in one basket. In reality, a developed flood plain would have a number of

adjoining farmed areas surrounded by gerrymandering levees. The effect of the geometric progression

35 This presumes that the labor to sow and harvest the crop is trivial in comparison to the labor require for diking and drainage.

Tide Gates and the Neolithic Revolution 25 of 38

associated with a number of clans cooperating to construct levees would be tempered by reality and by

geography – but it would be impressive nonetheless.

I believe that the economics were irresistible and they drove humanity into ever larger agricultural

communities. The cooperation and prosperity resulted in peace and food security - as well as

unprecedented power and wealth for the ruling class.

The increased food supply resulted in an increasing population.

(1) More people can construct and maintain more levees,

(2) More levees means that more of the flood plain can be farmed,

(3) Resulting in more food,

(4) More food means more people – and back to (1).

This is a feedback loop with variables that grow geometrically. The farmed area within the levees grows

non-linearly as the population increases, and everyone knows that if resources are available, human

populations grow geometrically. Within a few centuries, the Neolithic Revolution would have resulted in

a population explosion and a substantial portion of the flood plain being covered with levees, drainage

ditches, tide gates and farmers. Efficient food production on even a small fraction of the flood plain of

the Tigris and Euphrates Rivers could and did support societies with hundreds of thousands of people.

As the levee, drainage, irrigation, and tide gate engineering/technology were perfected, more

challenging sites for levees and tide gates could be developed. With some ingenuity, agriculture in the

river valley above the tidally-influenced reach would ultimately be possible. Levees, ditches, flap-gated

culverts, aqueducts, artesian wells, and irrigation canals would be engineered to develop the flood

plains upstream of where regular tidal variations could be used for irrigation.

The efficient production of food and the large number of available workers allowed some fraction of the

populace to do something besides hunting and gathering, building or maintaining levees and tide gates,

or sowing, tending, and reaping the crops. Some of the Sumerians were free to develop mathematics,

astronomy, a written language, engineering, architecture, and all the other technologies of an ancient

civilization.

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Astronomy would be useful for predicting the date of the summer solstice as well as for determining

when New and Full Moons occur. The date of the Summer Solstice was used to determine when to

plant. New and Full Moons correspond with the highest tides of the month - when tidal irrigation is the

most feasible. It is understandable that in many ancient civilizations, including the Sumerians, there was

great interested in astronomy.

Political machinery evolved as the society developed. I speculate that Enlightened Engineers in ancient

Mesopotamia must have been admired and rewarded by the ancient rulers. These engineers probably

advised the ruling class.36 (The engineers should have been the ruling class – but I am biased.)

So What Was So Special About Mesopotamia? Answer: Good Government

I believe that something resembling my primordial Neolithic farm was independently conceived and

executed in a number of locations around the world between 5,000 and 10,000 years ago. What makes

Mesopotamia stand out is how far the civilization there advanced in a matter of just a few thousand

after their first Neolithic Farm.

For some reason, other river valleys with tide gates and primordial Neolithic farms got a late start

and/or were not as successful as the farms in Mesopotamia. The geography, tides, hydrology, river

hydraulics, soil, available plants, and climate may have been less than ideal. The imagination of the

Neolithic Engineers in other locals may have been inferior to the Enlightened Engineer(s) in

Mesopotamia. The natives simply may not have had the ability to get along and work together. The

Enlightened Neolithic Engineers outside of Mesopotamia may have been burned at the stake (or buried

alive in the swamp) after delivering their “I have a pipe dream speech”.

Ayn Rand may have been cynical, or she may have been prescient:

“Throughout the centuries there were men who took first steps down new roads armed with

nothing but their own vision. Their goals differed, but they all had this in common: that the step

was first, the road new, the vision unborrowed, and the response they received - hatred. The

great creators - the thinkers, the artists, the scientists, the inventors - stood alone against the

men of their time. Every great new thought was opposed. Every great new invention was

denounced.”

Howard Roark: In Praise of the Self - from The Fountainhead (1943)

Based on my personal experience in the current era, I can testify that a lack of wisdom within the ruling

classes can be devastating. Tide gate technology (a great new thought) in ancient civilizations outside of

Mesopotamia may have been opposed and completely sabotaged by poor leaders.

For contrast, Mesopotamia benefitted from some very wise rulers…

36 There were no Hollywood actors, entertainers, or 60’s-era radicals in ancient Mesopotamia.

Tide Gates and the Neolithic Revolution 27 of 38

Hammurabi was king of Babylon from 1792 BC to 1750 BC and was a famous lawgiver. Hammurabi’s

code survived on a large stone stele which was discovered in 1901. It is currently on display at the

Louvre in France.

Included in Hammurabi’s code is the following law:

If someone is careless when watering his fields, and he floods

someone else's by accident, he will pay for the grain he has ruined.

This law seems perfectly reasonable. More importantly, it suggests that watering in Mesopotamia was

not done by multitudes of people carrying water-filled animal skins from a manually operated well.

Flooding a field by propping open a tide gate on a day with an excessively high tide would result in

accidentally flooded fields. This must have actually happened on occasion to warrant this law.

The field could only be flooded if it was in a depression or if it was surrounded by a levee.

The law is also indisputable evidence that individuals actually owned their fields. Under Hammurabi, the

farmed land in Babylon within a levee was not a giant communal Kibbutz or a Soviet collective.

The ancient Mesopotamians had better than average politicians – at least while Hammurabi was in

charge.

Seeds of Destruction

As the cultivated land in the ancient society gradually subsided over the centuries, it became more and

more challenging to drain the fields. When some of the fields were finally abandoned and allowed to

flood, an epidemic of mosquitoes and mosquito-borne disease soon followed. This has occurred in a

number of places including San Francisco during the latter half of the 19th century and Italy at the close

of WWII.

With a significant fraction of the population disabled by

malaria37, the levees and tide gates went unrepaired. This

resulted in more standing water, more mosquitoes, more

malaria, and more dysfunction – the epitome of a vicious

cycle.

Harvests happen during the peak of mosquito/malaria

season - or more correctly: harvests should happen during

the peak of malaria season. The crops would have rotted in

37 Or any of a number of mosquito-borne diseases. (or Schistosomiasis… or Dracunculiasis.)

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the fields while the populace was immobilized with fever. Starvation and malnutrition added to the

unfolding disaster.

The historical record shows the rise and fall of a series of empires in Ancient Mesopotamia – suggesting

invasion and conquest. It was more complicated than that. Mosquitoes don’t write history; they just

make it.

It is likely that the levees and tide gates that made ancient civilization possible ultimately played a

pivotal role in their demise.

Good (and Bad) in Everything

…and this our life exempt from public haunt, finds tongues in

trees, books in running brooks, sermons in stone, and good in

everything! – I would not change it.

Shakespeare – As You Like It, Act II Scene 1

Unlike Shakespeare, I believe that there is good and bad in everything. If I were allowed to, I would

change it: More good and less bad.

The Neolithic Revolution was wonderful in many ways; however, it made slavery practical; it made large-

scale warfare possible; it encouraged water-borne disease and deadly epidemics, and it was essential for

the rise of politics.38

Slavery - Prior to the Neolithic Revolution, slavery was simply impractical. A slave would be another

mouth to feed, and what chores would a hunter-gatherer impose on his slaves? And how would he keep

his slaves from escaping?

During times of conflict, Stone Age people typically killed the adult males that they captured in battle. At

times, they also killed the women and children. There is archeological evidence that cannibalism was

fairly common among Stone Age people. Morality had not been “invented” yet and the nutritional

economics of cannibalism would have been irresistible - particularly during lean times.

Slavery was endemic in every ancient civilization and in nearly every society world-wide until just a few

hundred years ago. In civilized countries, cannibalism has been, for the most part, unpopular. Good and

bad in everything.

Prior to the invention of earth-moving equipment and CO2-belching internal combustion engines, the

construction of the infrastructure for civilization made slavery economically irresistible. After the

Neolithic Revolution began, the victors in a conflict would be much better off by putting their defeated

38 Including, in time, the remarkable rebirth of Obamunism.

Tide Gates and the Neolithic Revolution 29 of 38

enemies to work building levees and enlarging their farms39. The proliferation of levees and canals in the

flood plain after the Neolithic Revolution was underway made the enslavement of humanity more

sensible than cannibalism.

Charles Darwin would argue that being a slave is better than being an hors d’oeuve. At least a slave has

a chance to help preserve the race, and as bad as slavery was, cannibalism was even worse. The

environmental impacts of the Neolithic Revolution were/are cataclysmic; however, the revolution was a

major setback for the Jeffrey Dahmers of the world. And as supposedly bad as the industrial revolution

was, it made slavery economically obsolete. Try as they may, slaves cannot compete against tractors.

Warfare – Prior to the Neolithic Revolution, armies simply did not exist. There undoubtedly were small

and sometimes fatal skirmishes between clans on a regular basis, but nothing that could be called “a

war”. The population explosion and the rise of ancient cities made large scale war and mass carnage

possible.

As bad as ancient and modern warfare are, the carnage caused by water-borne diseases is far worse.

Malaria alone has killed more people than all of the wars in history.

Water-Borne Diseases - The human condition was greatly improved and individual life spans were

increased by the abundant and reliable food supply resulting from the agricultural revolution. It is

important to remember that the Neolithic Revolutions of the world occurred within river flood plains -

naturally wet and relatively flat environments. Drainage was a challenge and water-borne disease was a

serious health hazard for people living near a network of drainage ditches which frequently contained

stagnant water. In addition to the stagnant water in drainage ditches, the surrounding untamed

wetlands would reliably propagate blood-thirsty mosquitoes.

The greatly increased human population density resulting from the Neolithic Revolution and the

displacement of the native animals generated evolution pressure which shifted the biting preference of

the mosquitoes to humans over other potential targets. The likelihood of a mosquito40

biting a person

infected with Malaria, Yellow Fever, Encephalitis, or Denge Fever, and then biting and infecting one or

more additional people before the mosquito expired increased dramatically with the growing human

population.

The plasmodium parasite’s chain of transmission between mosquitoes and humans, the mosquito’s

amazing rate of reproduction, and the rate that the Plasmodium parasites propagate all involve

remarkable geometric progressions. They combine to produce a devastating phenomenon: A Malaria

Epidemic.

In 1881, Dr. Carlos Finley was the first physician in the current era to suggest that mosquitoes were the

vector responsible for Yellow Fever and Malaria. Maybe the ancients made the connection as well, but I

39 A full belly doesn’t last long and refrigeration would not be invented for thousands of years. 40

Not all species of mosquitoes are vectors for disease. Mosquitoes of the genus Anopheles (from Greek anōphelḗs = useless, hurtful, harmful) are carriers of Malaria. Mosquitoes of the genus Aegypti (and others) are carriers of Yellow Fever.

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rather doubt it. In 2012, The “Ask the Malaria Coordinator” with USAID could not comprehend that

there could be any connection between 3,000 flap-gated culverts for a proposed flood control project in

Mozambique and stagnant water in drainage ditches breeding Anopheles Mosquitoes.41 If USAID’s Ask

the Malaria Coordinator couldn’t figure this out, the ancients probably were stymied as well.

With luck (or good judgment) some level of sanitation would be deemed desirable by the ruling class of

an ancient civilization. An individual with engineering ability would then develop effective drainage and

some level of sanitary engineering. An engineer could also design the infrastructure to provide the

burgeoning society with reasonably clean water. (Note that with proper engineering, virtually all water-

borne and mosquito-borne diseases can be controlled and effectively eliminated42.)

Malaria and Yellow Fever were common in some regions of America during colonial times and as

recently as the 1930’s. We declared war on Malaria43 by declaring war on mosquitoes – primarily larval

mosquitoes and their aquatic habitats. Americans did not rely on insecticide-treated mosquito nets or

vaccines to eliminate domestic outbreaks in the first half of the 20th century. The much derided chemical

insecticide DDT was only used for mosquito control in the US after WWII. The Mosquito Crusades had

effectively been won prior to the use of DDT.

Yellow fever was eliminated from the Canal Zone of Panama by 1906 primarily by controlling stagnant

water and thereby sabotaging mosquito breeding. (Malaria was eradicated in the Canal Zone a few years

later.) Engineers played a central role in eradicating Malaria in the US primarily through vector control

using larval habitat management.

Mosquitoes and mosquito-borne disease in Neolithic Societies were another matter. The wetlands on

the untamed flood plains surrounding the ancient diked and drained farms would support vast swarms

of mosquitoes. Unless they could drain all the swamps, the ancients were vulnerable to mosquito-borne

plagues.

If all or most of the flood plain was diked and drained, the natural pools used by mosquito larvae would

be unavailable for breeding mosquitoes. This helped reduce mosquito breeding; however, if the

drainage ditches on the Neolithic Farms were not perfectly graded to drain completely, at times the

ditches would hold stagnant water. In addition to propagating mosquitoes, the stagnant water in the

drainage ditches could have also provided habitat for a type of snail which is the host for the parasitic

worms that cause Schistosomiasis44 in humans.

Another water-borne disease known to have been experienced in ancient agrarian civilizations is

Dracunculiasis – also known as Guinea Worm Disease. Egyptian mummies have been examined and

found to contain mummified 3-foot long parasitic Guinea Worms.

41 I’m not making this up. 42 This has a much higher probability of success than developing vaccines for the long list of mosquito-borne diseases, or convincing people to tuck their kids into bed at night beneath insecticide-impregnated bed nets. 43 The American Mosquito Crusades began in 1901. 44 Also known as bilharzia, or Snail Fever.

Tide Gates and the Neolithic Revolution 31 of 38

With increasing human populations and standing water in the drainage ditches on the flood plains,

water-borne diseases would inevitably become a very unwelcome side-effect of the Neolithic

Revolution.

Politics – The growing population and the expanding infrastructure of the budding civilization soon

produced a political machine to direct the work and settle disputes. Initially the “rulers” might have

been the people who engineered the levees, drainage, and tide gates – a pure meritocracy. Eventually

this gave way to an aristocracy, dynasties, a ruling class, and a peasant class.

There were good rulers and bad rulers; peaceful times and times of war/conquest. Some rulers

advanced science and technology, and others politicized science while discouraging technological

innovation. There is nothing new under the sun.

Ancient civilizations benefitted from a number of positive feedback loops in addition to the rapidly

growing human population and the wealth that grew geometrically. Success was nearly certain in spite

of politics… that is, until diseases with even more powerful geometric progressions and strong feedback

loops decimated the empire.

In addition to slavery, warfare, epidemics, and politics, the Neolithic Revolution was the greatest

environmental disaster in human history.

I suspect that “the environment” was not a concern to the politicians in ancient civilizations. Political

environmentalism only began several thousand years after the greatest environmental disaster in

history – the Neolithic Revolution. Good leadership and practical environmentalism in ancient

civilizations might have saved the ancients from the seeds of their destruction.

Everything - Civilization and large scale social organization necessitated a written language, ethics,

morality45, religion, and laws. Buildings, temples, roads, and bridges were constructed. Art, science, and

the humanities advanced.

Mining, metallurgy, the petrochemical industry, machines, cars, trains, and planes, water pollution, air

pollution, plastic, landfills, banking, money, debt, Wall Street, corporations, politicians, etc, etc, etc.

There truly is good and bad in everything – and everything is the result of the Neolithic Revolution.

Tide Gates – The Nemesis of Wetlands

Since the dawn of civilization, pristine and productive natural wetlands have been lost due to diking and

drainage projects to create productive agricultural land. Farms seem tranquil and bucolic, however the

ecological impacts and habitat loss caused by agriculture over the thousands of years since the Neolithic

Revolution began are impossible to over-state.

45 “Starting tomorrow, No More Cannibalism. Now clean your plate!”

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Species extinction and the proliferation of exotic aggressive non-native species are the rule when

comparing diked and drained flood plains to undisturbed natural wetland habitats. The Neolithic

Revolution was mankind’s greatest achievement; however diking and draining land for the agricultural

revolution was arguably one of mankind’s greatest environmental disasters.

Unless we are willing to forgo our ability to grow food, the destruction of natural habitats is

unavoidable. The degradation of the waterways and watercourses that drain agricultural land protected

by levees and tide gates is another matter. These drainage systems can be designed and maintained in a

way that results in improved drainage while preserving some of the native riparian habitat and

enhancing the aquatic habitat. A narrow riparian strip on one or both sides of the primary waterways

that drain agricultural land would reduce water temperatures while providing important habitat for

birds, mammals, and amphibians.

A traditional tide gate or flap gate is closed by default and only cracks opens to pass water during low

tides and during the outflow of runoff. By design, it does not allow any backflow whatsoever. These

characteristics make traditional tide gates and flap gates significantly more environmentally damaging

than necessary. They prevent fish and amphibians from accessing habitat; they degrade water quality;

and during dry periods, they ratchet-down the water level with each low tide.

A Better Tide Gate

I have designed a much more environmentally-friendly tide gate that is wide open by default. It allows

some amount of tidal exchange by allowing backflow during the early portion of the flood tide and it

closes later on during the flood tide when necessary to prevent flooding. With my environmentally

friendly tide gates, the drainage ditches in agricultural areas protected by levees can be designed and

maintained so that they provide important viable habitat for native wetland plants, fish, waterfowl, and

wildlife.

The ebbing and flooding flow through a better tide gate fills and drains the drainage ditch on a daily

basis. This eliminates stagnant water, thereby controlling many vectors for disease46. The regular tidal

flushing also dramatically improves water quality. For a detailed description of how this works, go to

www.issuu.com and search for “A New Weapon in the War Against Malaria”.

46 Anopheles mosquitoes have been responsible for more human deaths than any other factor in the history of humanity. An estimated 600 million people world-wide are at risk of Schistosomiasis or “Snail Fever” infection.

©Jeffrey S. Juel 2013

Below is a photo showing the native vegetation upstream from “a better tide gate” that has been in operation at Edison Slough near Burlington

Washington since January 2009:

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The tide gate at Edison Slough was retrofitted with my VBFG (Variable Backflow Flap Gate) control

mechanism in January of 2009. The tide gate has been in operation without a single failure for over four

years. It has operated unattended with virtually no maintenance.

The vegetation upstream from this tide gate is spectacular and it is getting better every year. The

property owner who lives upstream from this tide gate reports that the drainage is improved because

the tide gate opens much wider and passes more water than a traditional top-hinged flap gate. The daily

ebbing and flooding flow through the tide gate improves water quality and also prevents the tide gate

from shoaling-in. There is NO downside to this.

The photo below shows the shoaled-in traditional top-hinged flap gate (foreground) that is adjacent to

my wide-open side-hinged VBFG (background).

Me standing on a half-buried top-hinged flap gate at Edison Slough (Golden Harvest model GH-39)

Prior to the retrofit of the side-hinged flap gate, the water upstream was nearly always stagnant,

disgusting and nearly lifeless. Runoff coming from upstream periodically flushed the stagnant water and

runoff into Padilla Bay.

My Variable Backflow Flap Gate significantly

reduces the direct impacts caused by one of the

greatest inventions & environmental disasters in

human history - Tide Gates!

Tide Gates and the Neolithic Revolution 35 of 38

What’s an Engineer to do?

Civil engineering / civilization was a veritable Pandora’s Box containing multitudes of modern problems.

By definition, you cannot put things back into Pandora’s Box. Even if you could, having humanity return

to a pre-Neolithic existence is a bit problematic. Unless we agree to respect cannibals and accept

cannibalism as a form of diversity, there just won’t be enough food to go around just a few weeks after

we stop farming. If cannibalism isn’t distressing enough, imagine the reaction from teenagers when their

cell phones stop working, and sending text messages becomes an exercise in futility. (LOL)

As engineers we can consider what we’ve wrought and develop a massive guilt complex. In my opinion,

this is uncalled for. Engineering is done under the auspices of the ruling class. We have very plausible

deniability. Besides, as bad as the world is, it’s also pretty darn good in most respects. Things could be,

and eventually will be, worse…

The earth has been hit by large comets sporadically over the past billion years. The resulting extinctions

and environmental damage make what humanity has done to the planet in the past 10,000 years look

trivial. Large comet impacts are, supposedly, very infrequent.47 It could happen tomorrow, but more

likely it will be tens or even hundreds of millions of years before the next comet-based cataclysmic

event.

Ice ages occur with a much higher frequency than large meteor or comet impacts. Glaciers thousands of

feet thick will do a nice job of scraping everything we engineers have inflicted on humanity from the

face of the earth. Most of the plants and animals that we’ve driven to extinction in the past 10,000 years

would probably have perished in the next ice age. If you think man-caused Global Warming has been

traumatic, imagine the inconvenience of 1,000 foot thick ice sheets everywhere during the next nature-

caused Ice Age.

The world is four billion years old48. It’s been through a lot – good and bad. As an engineer, I can only

strive to maximize the benefits and minimize the environmental impacts that result from the things that

I design. Politics ultimately trumps the will of engineers – we normally do what we are told by the

political machine. We are not free to pick and choose what we wish to do as engineers. This is the root

of the problem.

My advice to my fellow engineers:

Learn history and the role of engineering in history; be the best engineer you can be; and make the

world a better place. You can and should be proud.

47 I am still waiting to experience my first cataclysmic meteor impact event – and I’m getting pretty long in the tooth. 48

Creation Myths have no place in science: Mankind did not despoil a utopian Garden of Eden when earth was created 5,000 years ago. Similarly, the utopia promised by the secular humanists if humanity accepts their collective servility is also a myth.

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Civil engineers provide clean water and sanitation. This has saved more lives than all of the doctors and

medical breakthroughs in history. We can do even better: If you find yourself designing a drainage

system or an irrigation system, think about aquatic disease vectors!

Be ethical; seek the truth; question everything49; resist collective servility; don’t take credit for

something that you didn’t do; rise above politics; and read Ayn Rand.

Work within the system, and when the system no longer

works, shrug.50

Acknowledgements:

I thank my sons Jeremy & Jordan and my daughters Rachel & Rebecca for believing in me and

encouraging me to write this – and to not give up.

I thank the late Douglas Adams for writing his landmark book: The Hitchhiker’s Guide to the Galaxy. His

work inspired me to find the Answer to the Ultimate Question of Life, the Universe, and Everything. I

may have fallen short, but I believe that I at least found the Answer to the Ultimate Question of Life,

Earth, and Everything.

The real answer is not 42. (Be sure to watch a short and hysterical video hyperlinked here.)

The Answer is “Tide Gates”. The ultimate question that this is the answer to is:

“What caused the Neolithic Revolution to happen?”

Seeing that virtually everything important that mankind has created (a civil society, written language,

math, literature, science, technology, engineering and architecture, currencies, nations, politics, (etc.

etc. ) came about as a result of the Neolithic Revolution, the query above is the obvious Ultimate (non-

theological) Question of Life, the Universe, and Everything. (A very good question indeed!)

I also specifically thank Douglas Adams for his depiction of the fictional51 Vogon race:

Vogons are described as mindlessly bureaucratic, aggressive, having "as much sex appeal as a

road accident" and the writers of "the third worst poetry in the universe". They are employed as

the galactic government's bureaucrats.

49

The Conventional Wisdom is usually wrong. 50 You will know what to do after you’ve read Atlas Shrugged. 51 They may not be fictional.

Tide Gates and the Neolithic Revolution 37 of 38

These creatures allow me to find humor in what I’ve been forced to endure in my engineering career

while attempting (and completely failing) to promote something that is truly wonderful for wetlands,

fish, wildlife, and humanity.

I signed up for every engineering class taught at the University of Washington taught by Dr. Stephen

Burges and I ultimately chose him as my Master’s Thesis Advisor. I learned much and I could not have

written this paper without the knowledge that he passed on to me.

Putting Ayn Rand’s The Fountainhead on the reading list for his Hydrologic Engineering Design class

seemed a bit strange at the time. The Fountainhead was one of the most important books in my life.

Howard Roark is my hero; In Praise of the Self is my story:

… men of unborrowed vision went ahead. They fought, they

suffered and they paid. But they won.

(I hope I win…) Thank You Steve!

I also thank Karen - the gentle homeless woman who frequents the Starbucks near my home. She

reminds me a bit of my late mother. She gave me some very useful advice at a critical time when I was

completing this tract: “Sometimes you shouldn’t say what you think.”

I’ve excised about ten pages from this document as a result of her (and my son’s) admonitions.

I do not suffer fools gladly. I need to work on that.

I sincerely thank the Kitsap County SSWM staff. They made an honest and faithful effort to work with

me on an outfall and tide gate project for the Point No Point wetland that would have been a wonderful

thing. A few Vogons may have effectively sabotaged our efforts.52

52 Resistance is futile!

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References

Adams, Douglas. The Hitchhiker's Guide to the Galaxy. New York: Ballantine, 1995. Print.

Hardin, Garrett James. The Tragedy of the Commons. [Washington, D.C.]: American Association for the Advancement of Science, 1968. Print.

Patterson, Gordon. The Mosquito Crusades: A History of the American Anti-Mosquito Movement from the Reed Commission to the First Earth Day. Rutgers University Press, 2009. Print.

Potts, Daniel T. Mesopotamian Civilization: The Material Foundations. Ithaca, NY: Cornell UP, 1997. Print.

Rand, Ayn. The Fountainhead. New York: Bobs Merril, 1943. Print.

Shah, Sonia. The Fever: How Malaria Has Ruled Humankind for 500,000 Years. New York: Sarah Crichton /Farrar, Straus, and Giroux, 2010. Print.

Weisdorf, J (2005). From Foraging to Farming: Explaining the Neolithic Revolution. Institute of Economics, University of Copenhagen.

…and every book and magazine that has ever been written. None of them would have been possible were it not for the Neolithic Revolution.