Californians would pay almost anything for the equivalent of our Canterbury Central Plains irrigation scheme.

The Golden State has been under a serious fresh water shortage for many years because of low rainfall, droughts, a shortage of melting snow and many farming irrigation water rights going back some 80 years.

So what are some of California's water issues?

For a start its population of 39 million is the highest of the United States. California cities use 10-20 per cent of the states' fresh water with rural California soaking up the other 80-90 per cent. There is a serious debate looming regarding water for cities versus water for industries and it looks as though sooner or later it will get to the US Supreme Court.

The cities and towns produce 98 per cent of the states' gross domestic product and rural the other 2 per cent. Much of the rural water is spent on growing alfalfa (lucerne) and hay for cattle. Alfalfa is a huge water user, particularly as quite a large area is flood irrigated. About 70 per cent of this feed goes to dairies.

The 500,000 beef cattle in California use, one way or the other, some 4000-8000 litres of water for each kilogram of meat produced and sold. Water for livestock production uses 75 per cent of the Colorado River flows which are 15 per cent lower than they were in 1990.

In April 2015 the California governor made an executive order to the towns and cities to cut their water use by 25 per cent, but not farming. The state and much of the west relies on snow pack each winter, but this is the fourth year that it has been below normal. Aquifers or ground water are being significantly drilled into, but are being severely depleted on a regular basis.

Furthermore, Californians had a major drought in the late 1970s, but at that point there were only 20 million people and the population has increased to 39 million.

Certainly water use has become much more efficient over the past 30 years, but with the aquifers (ground water), much of which is not renewable, there is real trouble coming because there is no other fresh water backup. Desalination can make up some of the differences, but it is expensive, energy-intensive and is a long way from a solution.

California farmers could lease out their water rights annually for $700 an acre-foot (an acre-foot is one acre of ground covered by one foot deep in water). This is more than they could earn in most cases by using the water to grow crops. One acre-foot of water is about 1,482,025 litres which is enough to supply two typical families for a year.

In 2014 the drought forced California farmers to fallow 202,000 hectares with this area looking to be on the rise for 2015. Western Growers Farming Association estimated 17,000 farm jobs were lost in 2014

California is the world's fifth largest supplier of food and its current drought is the driest period in the states' 163 years of recorded rainfall history. Its nearly 405,000 hectares of almond trees consume the equivalent of 120 per cent of the total water currently used indoors in all cities and towns in California.

Alarmingly, in some areas of the Central Valley the land is sinking by one foot or more each year.

Here is another scary fact - California's present population of 39 million is estimated to increase to 60 million by 2050 which is only 35 years away.

Work is underway, though, to control water use. Every toilet in California now has a maximum consented flush of 5.8 litres, down from 7.3 litres in 2007. The water infrastructure and the dollars spent on it to date are enormous. There is a 715 kilometre California aqueduct which delivers water to the San Joaquin Valley, parts of the San Francisco area and southern California. This is the largest aqueduct system in the world. Of the 1400 water reservoirs in California, most are less than half full and have not been near full for many years.

Because water for lawn sprinkling is banned in many areas of California there are some areas around houses and other buildings that are painted green – there are ow painting contractors specialising in this activity.

When you stop and talk to farmers in California, as I have done, they refer to their long standing water rights and how crucial they are to them. There is still quite a bit of wild flooding and when you ask them about the annual cost of the water itself, there are certainly some ongoing operating costs as well as a share of the various schemes' pumping and administration costs. But for most farmers the actual water charge itself is low, at least relative to its current commercial value.

After a few hours of these discussions one can see the value of having the annual water use cost being priced more on an efficient use and return basis. This has happened to some degree in Australia where Melbourne city has bought rural water rights. They have been paid market prices, but owners of the farmland selling their water rights often then do nothing with the land left. This is quite noticeable in areas along the Murray River in Victoria.

The lesson perhaps for New Zealand from this is that we are well off for fresh water, but need to focus on water storage.

I have felt for a long time that the Government needs to take up a cornerstone 25 per cent shareholding at the outset in our larger irrigation schemes as getting them up and running is in many cases beyond farming couples. Obviously the scheme would need to be well planned, researched and implemented, but the Government couldprobably sell down its 25 per cent interest gradually over the following 5-10 years at little or no capital loss and maybe even at a sound profit.

A trading of water rights scheme further out looks as though it would focus farmers to use the water available in the most return efficient manner.

Almost certainly there will be ongoing wars over fresh water around the world in the future. Climate change and volatility is going to put more and more focus on water storage, distribution and efficiency.

We need to support the Central Plains Water scheme because it is real progress for Canterbury farmland and its farmers, the country's exports and New Zealanders as a whole. Fresh water and its use is one of New Zealand's major strengths and we need to exploit it for our children and grandchildren. Water will open up all sorts of options and strategies and, yes, we may struggle to finance its development, but that is what future proofing is all about.

PS: The metric system has not really caught on in the United States where acres, feet and inches still reign supreme, unless you count the increasing popularity of the nine millimetre bullet.

Pita Alexander is a specialist farm accountant at Alexanders.