While we have every belief that our proposals will have a strong beneficial impact on the current water situation in North America we must also prepare contingency plans in case the situation worsens at an increased rate due to population growth and climate change. Many engineering based solutions have been investigated over the years, largely by nations who are already facing an acute water crisis. Some Middle Eastern states share around 1% of the world's water but their proportion of the world population is about 8%, rising at a rapid rate (MidEast at a Glance and U.S. Census Bureau; n.d. and 2006). They are experiencing an even more severe water crisis in these areas and as a result, have had to consider far more drastic measures. We can use these countries as models when trying to imagine the USA in a very severe and prolonged water crisis.
Water is currently a relatively inexpensive commodity and hence it will be difficult to recover the costs of implementing many of these large scale solutions. As such these solutions are intended for use when either water is valuable enough to justify the cost or the situation has deteriorated to such an extent that these contingency plans must be implemented.
Pipelines are considered to be the most efficient way of transporting fluids and are used extensively by the petroleum industry. Building a new pipeline is a very large undertaking due to the many secondary studies which have to be carried out to ensure its success and long term stability. For example, when the State of Alaska built the Trans-Alaska Pipeline it had to snake the pipe through the terrain to ensure there wouldn't be a catastrophic rupture in the case of an earthquake. Detailed surveys of the ground in which the pipe was to be laid also had to be done to check the maximum and minimum temperatures and that corrosion was within acceptable limits. In the 1970s there was a debate over the practicality of building a pipeline from Alaska to California to help redistribute some of USA's water to where it was needed. One of the suggested routes included a direct underwater path which greatly reduced the length. The project was found to be too expensive per cubic meter of capacity and while this remains true today it may not be in the future when we may be faced with a dire situation. The feasibility of the pipeline was further questioned due to both potential earthquake damage and the vastness of an underwater trench wider than the Grand Canyon. However, if Canada could be persuaded to cooperate, an overland pipeline could be constructed which would be far easier and could even be built concurrently with the oil pipeline being tabled.
Even though an underwater pipeline is impossible with existing technology it may be achievable in the future and elsewhere and it is important that this continue to be investigated. There are numerous underwater pipelines around the world, including one from the Florida Gas Transmission Company linking Southern Texas to Southern Florida used for the transportation of natural gas (Panhandle Energy n.d.). The Allies even managed to lay one from Britain to France during Operation Overlord to supply British vehicles with fuel (Operation Pluto). Anything is possible if the demand is sufficient.
One solution that has been considered is to use the now outlawed fleet of single hulled oil tankers to transport water. In 1978 the international community met in the wake of a sequence of oil spills in 1976-77 and began implementing new legislation to reduce oil pollution. In 1992, a further amendment to Annex I of the treaty was made, making it mandatory for tankers to have double hulls and providing a schedule for the phasing out of single-hull oil tankers. (International Maritime Organization 2002) These single-hull ships were felt to be too prone to rupture, especially due to low energy collisions which are most common in and around ports. The fleet is gradually being removed from service over the next 20 years.
Many credible groups and governments in water scarce areas have investigated the use of these ships to transport water but it was found to be economically unworkable with water at its current price as it is very expensive to sanitize the tankers. (AlShindingah Online 2002) To do so require the container's surfaces to be sand blasted but even then the process has not proven to be 100% effective. Nonetheless, this option must still be considered because tankers are very efficient, second only to pipelines. The vessels that would be required are already built and will be sitting idly or scrapped otherwise so if the water crisis continues to deteriorate, this will be one of the easier initiatives to undertake. Because of this, it may be prudent to ensure some tankers are reserved for these purposes and conduct some research into better cleaning methods. These new methods may eventually be efficient enough to allow any oil tanker to carry freshwater on its return voyage, bringing drinking water to the many oil rich but water poor nations around the world. (International Experience of Importation n.d.)
A second possibility for sea transport is the development of new types of oceanic vessels suitable for carrying freshwater over long distances. Some new ideas have been suggested in recent years, including the Kraken (Powell 1130-1137). This ship can carry up to 25 billion gallons of water every voyage, a volume large enough that you could even earn a profit of $8 million for a 5000 km shipment if you were selling the water at current market prices ($1 per 100 gallons). There are several classes of such vessels, each intended to carry a different cargo, but the largest is 2.5 km long and 200m wide, using superconducting coils to maintain its structure. The Kraken is an example of the application of new technologies to solve the water crisis, showing that new solutions can be found if scientists and engineers look for them. For something on the scale of the Kraken to be built, there would either have to be financial incentives for companies to invest or enough public urgency to encourage governments to fund R&D. We should start such developments now, even if it is on a small scale, so that we aren't forced to rush production of incomplete designs in a time of crisis instead of employing a well thought out and highly effective vessel.
Innovative ideas like this have already yielded results. Since freshwater is less dense than seawater, it will float on seawater. Engineers and material scientists have collaborated to exploit this characteristic and the result is a water bag which can be towed by existing ships and carry commercial quantities of freshwater over relatively long distances. Such systems are already in use in Greece and Turkey, supplying water to the network of islands in that region. Nordic Water Supply ASA has been contracted by the Turkish Ministry of Energy to transport drinking water to Cyprus from the Turkish mainland. In 2001 it transported 2 million cubic meters of water (Al Shindagah Online 2002). Its next stage of development is to expand to 6 million cubic meters and begin delivery to the United Arab Emirates.
The technology is still rather new so all of the bags on the market are made of lightweight but strong and flexible polymer materials, often with metal caps at either end to allow secure attachment and loading/unloading. One example, the Medusa bag, is currently being developed to hold either 500 000 (465m x 110m) or 1 500 000 cubic meters of water (670m x 160m) (MH Waters PTY LTD 2005). Spillage's have occurred in the past, normally while loading or unloading, but there has been no discernible effect on the local environments as the water is generally being pumped from rivers which would have otherwise discharged into the area anyway. Equally there has been no discernible effect of removing such freshwater discharge. It has many benefits over tankers due to it's reduced fuel requirements, lower crew requirements and less need for large port facilities. Most of the time these bags can simply be anchored to the sea bed whilst a port boat brings over a small pipe to connect to the end and unload the water. Though most of the work carried out so far has been near-shore transport, there have been many investigations and planned implementations on varying scales around the world, including California, suggesting that this is definitely a technology to be developed in the future.
The possible solutions available for the dwindling water supply of western North America are large scale projects of either type designed to create new water systems or those designed to mix current ideas with existing technologies. In the 1960s, several engineering firms proposed schemes to divert water from Canada and Alaska into the USA and Mexico. These plans would provide enough water to solve the current issues but there were many secondary considerations with the environment and water level reductions in northern areas which have never been fully investigated due to political blocking. Two examples are the GRAND canal scheme and NAWAPA project. These were both hugely expensive, costing billions of dollars by all estimates but they are still being researched by different groups, some of whom have drawn up improved proposals which are altered to meet revised future predictions on population, water use, etc. These projects are truly the last option as they are very invasive and could potentially have dramatic knock-on effects in the future which have yet to be understood.
However, before we get to that stage, we could also try to mix some of these new technologies with current ones. An example might involve the transporting of icebergs and desalination technology. Currently a large part of the cost in desalination is used in heating the water but this could be reduced if the water being used was less salty to begin with. We could engineer this by towing the icebergs to the desalination plants and letting them melt in the water nearby, releasing large amounts of freshwater in the process and reducing its salinity. You would not want to tow the iceberg very far so these desalination stations are likely to be more remote. If that were the case you would then have to integrate one of the transport technologies mentioned above. Integrating proven technologies with new ideas and systems is an alternate method to help solve the water crisis without resorting to hugely drastic measures.
For further reading