Saving Venicefrom the Sea

Economically and Easily!

Venice is a Historic City

• For many centuries, Venice was a prominent world trade center. But for hundreds of years, it has slowly been sinking, due to a natural process called subsidence. Venice has always been low, being a collection of 118 small islands, where gondoliers pole tourists around the city in the canals.

Still sinking!

• In recent decades, Venice has sunk so low that boardwalks are now installed above nearly all walkways, so tourists do not have to walk through mud and water.

Rising Mediterranean Sea

• In recent decades, the situation has become more complicated by Global Warming. As the Earth slightly warms up, the polar ice is melting, adding additional water to the oceans. This is causing the ocean levels to be rising. So, while Venice continues to sink, the oceans and the Adriatic Sea are rising.

A Bleak Future• In only fifty years, it is possible that much

of Venice will be uninhabitable. Equally importantly, tourists will stop coming to Venice and a large source of local income will disappear.

An Expensive Possibility

• For several years, some companies have been trying to get the governments of Venice and of Italy to finance an incredibly expensive project, which hopes to hold the Sea back. The estimated cost is around three billion euros. For this, the companies propose to build huge movable metal doors between the outer islands.

Trying to hold back the Sea

• The movable doors would resemble the doors in the locks of a canal. They would be opened and closed as deemed necessary by the City leaders, as during high tides and during storms. There has already been considerable argument over who would have the final authority to open or close the gates.

Gate Disadvantages

• Some people have been concerned that pollution within the lagoon might be trapped inside the gates for long periods of time, possibly affecting the eco-culture of the lagoon. Others worry that the gates, intended to only be closed at high tides and during storms, might soon start to be used nearly continuously.

Long Term Problems

• There would be no reason to believe that Venice would quit sinking or the sea would quit rising. It appears that the Adriatic might regularly start submerging some of the outer islands within 30 years. The existence of metal gates between the islands might become irrelevant if the Sea could just flow over the many islands too.

A Temporary Answer, at Best

• Given these things, it seems that the gates would only represent a temporary solution, at best. For Venice (or Italy) to spend billions of euros in the hopes of giving the city only 20 or 30 more years seems questionable. In addition, that approach has never been tried before, and it might not even accomplish the intended goal.

A Better Alternative?

At least, one more thing to try?

Actually Raising the City!

• There appears to be a realistic chance of physically raising Venice and the entire region around it! The following will discuss a method which should raise the entire area’s land surface by around one inch (2.5 cm) per month. In a year, that would raise the City of Venice by around one foot (30 cm).

Impossible??

• This sounds impossible! Clearly, there are countless billions of tons of soil and buildings in the area. It would seem to need some impossibly large force to raise it all.

Water is the Answer!

• As amazing as it seems, water provides the solution! Simple, normal water!

• It’s “secret” is that is is nearly incompressible!

Geological History of Venice

Rivers transport sediments

• In inland mountainous areas, rivers tend to be steep, so the water runs fast. Fast moving water acts to erode rock and other earth materials and also to carry those materials in its flow. This erosion is generally as small and moderate sized particles carried by the moving water.

Deposition

• Where the water in a river slows down, such as where it broadens to enter the sea, most of those suspended particles get dropped. This Deposition of material is common along many coastlines, and especially near where rivers meet the sea.

Variations in Deposition

• If the river water enters the sea at high speed, little deposition occurs, and that tends to only be the largest of particles, actual rocks. All smaller particles get carried far out into the sea, to later be deposited on the sea bottom. When the water moves more slowly, smaller particles can get deposited nearer the land.

Sedimentary Layers

• At many times, a river flows at a speed where coarse sand sized particles (in the range of 0.2mm to 2mm in diameter) are deposited in a river delta, [or even fine sand (0.02mm to 0.2mm)] while still smaller particles are carried out to sea. If this situation continues for tens or hundreds of years, a considerable thickness of a layer of sand can get deposited. But rivers rarely flow at constant speed for thousands of years.

Slower River Flow

• Sometimes the flow rate is much slower, such as when the water empties into a lagoon. In this case, the very fine particles being carried in the river water have a chance to get deposited. Over an extended period of such very slow water movement, a substantial layer of these very fine particles, called clay, can be formed. Clay particles are amazingly small, as small as particles of cigarette smoke or the size of a wavelength of light! (around 0.0001mm across)

Alternating Sediment Particle Size

• Nearly all rivers have had alternating periods of depositing sand-sized and clay-sized particles during their very long lifetimes. Since each layer covers all previous layers, this results in a “stack” of such layers, of varying particle size.

Porosity

• All of these particles do not “fit together” very well. There are always pore spaces between the particles. When all the particles are around the same size, as with sand, it turns out that around 40% of the volume is in these empty pore spaces. We would say that the porosity is around 40%.

Permeability

• Even though the porosity is similar for large sand and tiny clay particles, they have a major difference. The clay particles are so small that they are not much larger than water molecules. They are also generally flake-shaped and not spherical. The water molecules then have a hard time fitting through the pore spaces, so water flows very, very slowly. Such material is called impermeable.

High Permeability

• In contrast, sand sized particles have pore spaces which are extremely large as compared to water molecules. Water flows very easily through such material, and it is called highly permeable.

Permeable and Impermeable Layers

• This all results in the deposition of various permeable and impermeable layers. Water easily flows through the (sand) permeable layers and almost cannot flow through the (clay) impermeable layers.

A Water Well

• When a water well is drilled, it is always into a permeable layer. This is so that additional water can flow (percolate) through the layer to replace water that is removed by the well. A good well driller can make a well that rarely ever goes dry, because it draws from a reliable permeable layer.

Venice Industrial Boom

• From around 1930 to 1950, Venice experienced an industrial boom. Many new factories were built in the nearby Port Marghera area. Many industrial processes require large amounts of water, so many new water wells were drilled. All was well, for a little while!

Catastrophe!

• The City of Venice sunk unusually rapidly around that time, sinking around 22 cm (9 inches) more than was expected. City leaders soon associated those wells with the city’s rapid subsidence, and all those wells were ordered stopped. The rate of subsidence soon slowed to its usual rate.

Why?

• What had happened is this. Water that had been in the sand layers deep under the region had applied a natural hydrostatic pressure which helped to keep the sand particles slightly separated. As water was withdrawn from the wells, the particles could “collapse” closer together, so they became compacted and took up less volume. The land surface sank!

Important Detail

• It is important to note that the pore spaces did not and cannot disappear! Even in the San Joachim Valley in California, where farmers irrigating fields removed so much water that the land surface dropped over 30 feet (10 meters) vertically, the pore spaces still exist between particles.

The New Idea!

• Maybe it is obvious by now! But I propose to simply REVERSE the pumps on the wells and pump (river) water DOWN the wells. Water is essentially incompressible. If a cubic meter of water is pumped down a well, it has to go somewhere! It cannot shrink or disappear. Where it goes is into those pore spaces between particles.

Adding Volume

• As additional volume of water is added down at the bottom of the wells, there are only three possibilities: (1) the water could seep horizontally away from the area; (2) the water could seep upward toward the surface; or (3) the water would act in using its natural hydrostatic pressure to fit between the sand particles, taking up volume.

Horizontal Seepage

• Some horizontal seepage is to be expected, where injected water moves out from under the region. However, water flow through permeable layers is relatively slow, commonly on the order of a few feet/meters per day, rarely over 100 even for the most permeable layer. A continued injection of about 1/3 as much new water down the wells should easily replace all the water lost in this way.

Vertical Seepage

• This is where the importance of at least one impermeable (clay) layer arises. As long as one such layer is present above the permeable (sand) layer where the water is injected, the water could not get past it to get up to the surface. Most sedimentary profiles include a number of impermeable layers. Injection should probably be done as deep as possible to be beneath as many layers as is practical.

What if the impermeable layer has gaps?

• Of course, overlying impermeable layers are likely to have gaps or flaws in them, where water could seep upward past them. If this should be the case, small gaps might not be a concern. There is not an enormous pressure differential being added down at the bottom of the wells. If any of the water manages to reach the surface due to that pressure differential, it would likely simply flow out and not be a geyser!

NOT a Water Balloon!

• It seems necessary to clarify that this concept is not in “creating a cave and inflating it with water!” That might work, but everything would have to be sealed up, the outer edges of the permeable layer, etc. This concept instead just relies on mutual effects of small particles and water, like surface tension, capillary action, etc.., for the improved situation.

Seems worth trying!

• Venice’s situation is terrible. If nothing is done, within 50 years that historic city will be constantly below the Adriatic and therefore uninhabitable. Even if there is the chance of water seeping up past impermeable layers, the low cost seems to make this concept worth trying. There IS NO ALTERNATIVE!

Layer Repairs?

• If the general concept shows promise (as demonstrated in the test described later), but there are a few gaps in the impermeable layers, there should be a number of possible repair solutions. For example, when concrete bridge caissons are poured deep underwater, the situation is not that different from using the same type pumping equipment to inject concrete into a specific gap in an impermeable layer.

Success!

• After conceding that 1/3 of the injected water will eventually (very slowly) flow horizontally away through the permeable layers, and not losing too much upward, this leaves 2/3 of the injected water remaining in the permeable layer. But why is this a good thing?

Hydrostatic Pressure

• Any fluid, including water, exerts an equal pressure on all surrounding surfaces and objects. Water deep underground has a “natural” hydrostatic pressure, around 15 PSI (100 KPa) for every 32 feet (10 meters) of depth. At 30 meters (100 feet) depth, that natural hydrostatic pressure is therefore around 45 PSI (300 KPa).

Car on Waterbed Time-Lapse

• This heavy car is being raised (slowly, over 3 hours) on a standard waterbed! Less than 1 PSI of pressure was used to lift it, and only 0.3 PSI of pressure is needed to support it! Water could have been blown in by mouth to raise this car!

Pump Adds Pressure

• If a standard industrial pump is only rated at 50 PSI (330 KPa) pressure load, when water is pumped down a well, that pressure would add to the existing natural hydrostatic pressure. Even though this added pressure does not seem very great, it applies in ALL directions, specifically on the underside of the impermeable layer above it.

Lifting Power

• If only 50 PSI (330 KPa) additional is applied to that upper surface, consider how much total added lifting force would push upward for an acre of area. An acre is about 43,000 square feet, or about 6 million square inches! Every one of those square inches would be pressed upward with a force of 50 pounds. The total added lifting force would be around 300 million pounds or 150,000 tons. ONE pump is likely to provide enough water for about 130 acres, to provide about 20 million tons of added lifting force!

Raising Force

• This added lifting force joins the natural hydrostatic pressure and mechanical particle contact that is already supporting the layers above. The point is, there is plenty of available lifting force to raise the entire region. But it would occur rather slowly.

How Much Pressure is Needed?

• Given the enormous masses of material, it might seem that high pump pressure would be necessary. Not true! Consider the present situation at the underside of that impermeable layer. If any “net force” was now acting on it vertically, movement would occur, as Newton clearly explained (F = m * a)

Even One PSI would Work!

• If even ONE PSI of pressure is added to the water beneath that surface, that pressure would push upward, in addition to the existing pressures (of material plus water) that currently support the layers above. So even 1 PSI of added water pressure beneath the impermeable layer necessarily causes the F = m * a and the impermeable layer would have to rise!

• This discussion presents higher pressures in order to raise the land more quickly and because standard industrial pumps normally provide such pressures. In order to achieve a one inch per month rise, a considerable amount of water needs to be injected, and that higher pressure is needed to distribute all that water through the permeable layers.

Scale Model Time-Lapse Demo

• This scale model of sedimentary layers, including one of clay, shows the lift effect, and that subsidence is somewhat reversible, with continually added water. The water was added at 0.2 PSI.

To Just Not Sink Further?

• If Venice did not want to raise their city, they could certainly use this technology to maintain the current altitude, with a minimal amount of water injection and very minimal pressures. In that case, 1 PSI additional pressure might be enough!

Standard Pumps and Wells

• Notice that no expensive or exotic equipment is involved here. Standard industrial pumps attached to standard water wells is all that is involved, plus a source of water. Nearby rivers make that an easy matter.

The Big Picture

• Say that an area of 500 square kilometers (200 sq. miles) was to be raised, a rather large area. Simple calculations show that one inch (2.5 cm) thick of water for that area would be about 13 million cubic meters of water. That is certainly a lot of water!

Pumping

• Even a modest sized industrial pump can pump 400 liters (100 gallons) per minute. This is around 600 cubic meters of water per day, or 18,000 cubic meters of water per month. If 1,000 such wells / pumps were installed, they could pump 18 million cubic meters of water into the ground each month.

Accounting for Losses

• Even if 1/3 of that water would be lost due to horizontal seepage, that still provides the added volume of water in the month to raise the entire region by one inch (2.5 cm)

Month after Month

• Every month, the region could be raised another inch. With the extreme accuracy of modern instruments, the precise raise of altitude would be easily monitored. At whatever point that the City leaders in Venice felt the altitude was sufficient, around 2/3 of the pumps could be shut off. The other 1/3 of them would keep replacing water lost to horizontal seepage.

No One Has Ever Tried This Before!

• As far as I can tell, no one has ever tried to raise a land surface by artificially adding incremental hydrostatic pressure before. So no previous research or attempts are available as references! A number of artificial water injection systems are successfully operating, such as Orange County, California, which injects fresh water to keep saline seawater from laterally seeping in under their cities, and to keep the land from subsiding.

Could it be Tested?

Confirming the Effect

• This whole project is very economical, probably using many existing wells and pumps. However, before seriously applying it, there is a simple way to prove that it works! A single existing well could have its existing pump plumbing reversed, at essentially zero cost. That one pump could be operated for a month.

Precise Altitude Monitoring

• Some local University could measure the precise altitude of several nearby locations. It would immediately become obvious that the land was rising, on the order of the one inch during the month, and even more right near the well. Essentially without any capital investment at all, the City leaders of Venice can see if it is worth pursuing.

Does not Interfere

• Note that this concept does not interfere with any other approach, such as the movable gates out in the lagoon. And where those gates could only start to have effect around ten years after their project is started, this approach would show positive results within one month!

Local Businesses

• It seems likely that many local businesses would jump at the chance to contribute a pump or a well or some funds toward saving their city. It might very well result that Venice would not have to pay a single euro in saving their city! Imagine the P/R that such companies would get in making such gestures!

Every Inch Matters!

• Virtually all experts agree that even a single inch of altitude is critically important to Venice and its future. In just one month, it should be simple to physically raise the entire region by that much! Every month, for several years!

Faster??

• If even more wells were drilled, or more water pumped down the wells, it would certainly be possible to raise the land even faster. That could be done, as long as careful monitoring was done to see that all areas were rising at the same rate. If very rapid rise was tried, any differential rising might crack some building foundations. Slower might be better!

Unnoticeable

• The rise of one inch per month would be absolutely unnoticeable by residents or tourists. All they would see is that the wooden walkways could be removed in a few months, and Venice could again be in its prime.

No Downside

• This approach has no downside! Water naturally seeps down into sedimentary layers anyway. This project just helps that to happen faster!

Water from the Adriatic?

• The nearby availability of water from the Adriatic Sea might seem attractive, but it should probably be avoided. If salt water were injected into the wells, any existing nearby water wells might become contaminated. Also, the pore spaces could get clogged with salt crystals and equipment and pipes would corrode.

Excessive Horizontal Seepage?

• Even if it were found that excessive amounts of water was seeping away, extra pumps and wells could be added, to still produce the lifting effect on the layers that support the city.

My Gift to Venice

• It seems certain that I could have made a lot of money regarding this concept, since Venice is is such a difficult situation. However, as a Christian, I feel my Lord wants me to aid those people who are in need. If the City can be saved, that will be payment enough for me.

Questions?