Monthly Archives: January 2016

Environmental Water

We all use water extensively everyday for drinking, washing and water involved in the making of the products we consume. Most of the water used in society is in irrigated agriculture. As masters of the planet, we have a responsibility to ensure other species get their fair share of water too. We also want to ensure future generations are able to enjoy living among wildlife as we and previous generations have enjoyed.

Many in the water resources sector call this “environmental water”. Humans have built extensive dams and water distribution infrastructure, so as well as being able to provide water to ourselves for human needs, we can also provide water to the environment.

Water In The Desert

Environmental water is usually just water released from dams with the instruction to irrigators not to use it. This way the water makes its way to the environmentally protected areas untouched.

Along the way, the rivers will rise to their natural levels because water isn’t being taken out. This flushes the reed-beds and so on in the riparian environment with water. Plants and animals beside the river thrive with the additional water.

Lakes along the way become full and fish stocks that were depleted by humans recover. These wetlands provide a safe habitat for many birds and similar wildlife. Essentially we are restoring the environment back to it’s original state.

All of this can be achieved at minimal cost. All it requires is for irrigators to not take out any water that’s released from dams. This means dams need to store more water than that used for humans. If we want to live in a world where every species is respected and where future generations can observe the natural environment, this is a small price to pay.

Why Do We Need Water Transmission?

We don’t always! Obviously there are parts of the world with enough rainfall to support non-irrigated farming and locals can use tanks for household water. There are those near rivers and then there are those that can use groundwater.

This question was recently posed to me, why bother with all of this infrastructure if we can just move to where the water is? It makes sense at first, we shouldn’t live in dry areas. We shouldn’t farm in dry areas.

While we shouldn’t go to the other extreme of trying to live in a desert, it’s well worth noting the reasons why we don’t just move to where the water is.

  • Frequently the wet areas are too hilly for cities and civilisation.
  • Many crops prefer to grow in dry climates, but still need water.

There are other reasons, but these are the two main ones.

Water Pump Description and Comparison

As discussed in previous posts, the most efficient way to transport water is by pumping it. There are a number of factors that come into play when pumping water and these will decide the right types and sizes of pumps to use. When designing a water transmission system, you need to always have the view from the system’s perspective as a whole. Once you have the requirements for the system, such as distance, head, evaporation, nearby power sources and of course how much water is needed at what pressure, only then can you design the system.

Pumps get more efficient the larger they are and the more pressure they need to supply. This is where a systems perspective is important. If you can combine all the pumping into as few units as possible, you can get a more efficient and more cost effective system. This isn’t always possible because sometimes farms are spread out along a river, for example, and it’s easier for the individual farms to take water from the river with their own pumps.


Hand pumps have been used for thousands of years. Buckets were used in the early days and then a few thousand years ago other pumps were developed, some are still in use. There is the Archimedes screw and rope pumps, but the most common over the past couple of centuries is the reciprocating pump. This uses a piston in a cylinder to pump water to the surface.

In the 19th century rotodynamic pumps were developed and these are smaller, more powerful and more efficient than the older positive displacement pumps. Virtually all large pumps used today are of this type.

Rotodynamic Pumps

These can be largely divided into two categories:

  • Axial flow
  • Radial flow (or centrifugal)

Axial flow pumps are great for large volumes at low pressures. Radial flow pumps are great for lower volumes and higher pressures. The other benefit of centrifugal pumps is that they can scale down for small scale irrigation. Most pumps used for irrigation are centrifugal types today. On windmills and historic pumps you will find reciprocating pumps.

Pumping water is only part of the system design. You also need to work out the water transmission, be it open cut channels or pipelines. You also need to work out the power source. The most common power sources are electric or diesel and in old farms you will also find wind powered pumps.

There are many variables at play and designing a water pumping and distribution system is a complicated task.

Water Channels

As you might have read in the previous post, water can be transported by various means. The least efficient is by hand. In the developing world, many people still transport water from rivers, creeks lakes or wells by hand. They fill up their buckets with water and then carry the bucket to the location where they will use the water. This is slow and time consuming because you are limited to what you can carry.

A step up from this is carrying water in tanks on vehicles. Many businesses make money by carting water around in trucks and delivering it to where it is needed. In some towns, water is transported into town by rail. Large trains with tanker cars fill up with water where it is available and drive to the town where they unload.

All of these methods are relatively inefficient because they involve moving much more than just the water. In the case of the person with the bucket, they are moving themselves and the buck as well as the water. Even though a motorised vehicle can carry a larger amount of water, they still have to move the vehicle. A better way is to just move the water itself by pumping it or relying on gravity.

The two main ways you can do this are by pipes and channels. The previous post covered pipes, so this post will go into channels.

Why Channels Over Pipes

The big benefit of channels over pipes is ease of construction. You just need to dig a trench, line it so that it is impervious to water and that’s it. This is much cheaper than the cost of manufacturing a pipe and then you still have to do a lot of moving dirt like a channel.

When you need to move really large amounts of water, such as transporting water to a town or irrigation district, channels are preferred over pipelines because they are so much cheaper on the large scale. To build a huge channel isn’t as difficult as a huge pipe.

Another benefit is that channels can be used for boating. Here is a photo of boats on an irrigation channel.

Boats on Irrigation Channel

You can not do this with a pipeline because there is a roof over the pipe that would block the boats from passing through.

Disadvantages of Channels

One of the big benefits of pipelines is that they have lower evaporation losses. Water can evaporate from the top of a channel and it’s lost. So pipes are more water efficient.

Another problem with channels is that they always flow downhill. You can put in locks and dams to move boats and sometimes water upstream, but between the locks it has to be downhill. With a pipe you can put a pump on it and run the pipe gradually uphill. This is because with a channel if you pressurise it, it just floods the countryside where as with a pipe, because it’s enclosed, the pressure just builds up and there are no problems with laying it uphill.

There are pros and cons to using channels and the decision to use channels should be made on a case by case basis.

Pipeline Transport

Pipelines are used to transport all sorts of gases and liquids and even solids if they make a slurry. Coal and ore slurries can be transported by pipelines if there is enough water in them. What this post will cover is the use of pipelines to transport water.

Many of the worlds great civilizations have used pipelines to transport water to their cities. This is necessary because there is not enough rainfall in cities to supply the city with adequate water. Also streams and rivers under the city might not carry enough water.

The most notorious builders of pipelines in history were the ancient Roman aqueducts. Aqueducts are often associated with open cut channels, but they can refer to pipelines or any other sort of technology used to transport water. Many ancient Roman aqueducts were pipelines in fact, such as this one from Jerusalem.

Pipeline Transport

Ancient cities had the technology to lay pipes because pipes can be simply made from earthen materials. You can make pipes from stone and pottery. As the Romans are well known for, they used lead to seal their pipes. This drove some of them crazy because lead is a poisonous material. Fortunately, pipelines today contain no lead.

We still use pipelines because they use very little energy to transport water. Compared to transporting water in vehicles, pipes are more efficient. Also if the run is all downhill, there is no need for pumps or any external energy sources at all.

Pipelines do so much more than just transport water. They also protect water from impurities from the outside, such as bacteria, and they are also an on demand source of water. Trucks and so on come in batches, but for water out of a pipe, it’s always there and ready to be used. That’s why pipes have replaced buckets and bowls when using water inside the home.

You might find this resource helpful if you are looking for further information on pipelines.


Welcome to the Water Transmission blog! This website is all about water infrastructure and how we move water from natural sources to your taps, sprinklers and farms. There are many long processes involved in getting water to you, so we’ll cover them in upcoming blog posts.

I hope you find the content as interesting as I do when writing it. There’s nothing else more important than water and understanding how it arrives at your premises is something everyone should have an understanding of.

There are many uses of water, drinking and washing are the main ones that come to mind. However, these are very small uses of water compared to industry and irrigation. By far, the largest user is farmers who use water to grow the food that we eat.

So we can’t have food without water. Our water transmission infrastructure places most of the water collected naturally into farmlands where it is needed in the largest quantities. Another large user is water for industry, such as mining operations, factories and construction. These large users only need minimally treated freshwater, such as just filtration of the water. There is no removal of organic matter or treatment to remove transmittable diseases.

For drinking water however, different cleanliness standards exist. Town water goes through extensive filtering and purification before it arrives at the taps in your house. There is greater scrutiny placed over water transmission infrastructure for town water because of health reasons.

Water is an essential natural resource and this blog will cover how we transmit water from its collection to its uses. Please regularly return to this blog to read updates.