irrigation – Cabot Institute for the Environment blog

Mount Hount Huascarán, Cordillera Blanca, taken from Hauashao village. Credit: Susan Conlon

Water is essential for human life, but in many parts of the world water supplies are under threat from more extreme, less predictable weather conditions due to climate change. Nowhere is this clearer than in the Peruvian Andes, where rising temperatures and receding glaciers forewarn of imminent water scarcity for the communities that live there.

Peru holds more than 70% of the world’s tropical glaciers. Along the 180 kilometre expanse of the Cordillera Blanca (“white mountains”), more than 250,000 people depend on glaciers for a year-round supply of water. Meltwater from the glaciers supplies rivers, offering a vital supplement to rainwater so that locals can continue irrigating food crops throughout the dry season, from May to October.

But Peruvian glaciers have shrunk by 25% since 1987, and the water supply to rivers during the dry season is gradually decreasing. While national and regional governments and NGOs are responding to the threat of water scarcity with modern engineering solutions, there are growing concerns among the communities affected that such efforts are misplaced.

Modern day misfires

Take, for example, the village of Huashao. Nestled between the highest peaks of the Cordillera Blanca, Huashao is a typical farming village of the region. Glacier meltwater feeds the Yurac Uran Atma canal, which supplies irrigation water to families in Huashao. In 2011, a municipal government project transformed this canal from a rustic irrigation ditch to a modern PVC pipeline, with lock-gates to regulate the flow of water and ensure equal distribution throughout the village.

The village of Huashao. ConDevCenter/Flickr., CC BY-NC-ND

Governments and NGOs commonly promote modern measures to capture and conserve water for irrigation – for example, by lining irrigation canals with concrete, to prevent leakages. While it’s important to conserve water to safeguard food supplies, these kinds of measures have been criticised for their lack of flexibility and sensitivity to local needs.

While the pipeline in Huashao provided security and reduced the amount of time people had to devote to distributing water where it was needed, Conlon’s ongoing ethnographic research in the village found that local women were concerned about its effect on the local puquios (springs) – a valued source of irrigation and drinking water.

Noticing less water in puquios, they blamed the canal lining for stopping water from filtering into the local geology. Local communities see this process as an integral part of water distribution, but authorities often refer to it as “leakage”.

What’s more, the local people responsible for maintaining and operating the new canal found that not everything worked as planned. They were particularly worried when a problem caused water to overflow the canal walls, and blamed the design of the lock–gates.

Here, the government’s preference for modern engineering meant that it missed an opportunity to engage with traditional technologies and local knowledge. This is hardly surprising – ancient know-how has been routinely dismissed as inferior by state authorities and well-meaning (but badly briefed) NGOs. Yet traditional technologies, like the puquios, have been providing flexible ways to manage water in Huashao for hundreds of years.

In Huashao, the local people are coming to realise the limitations of modern engineering. But across the Andes, many other communities are still seduced by the promise of quick fixes offered by concrete, steel and PVC pipelines. Unfortunately, initial, costly investments of aid and expertise are rarely followed up, and since communities often lack the necessary knowledge and funds to maintain these systems, they eventually break down.

Ancient married with modern

Slowly, a push back is starting. There has been renewed interest in what society can learn from traditional irrigation systems. A recent international workshop held in Trujillo, Peru, brought together social scientists, geographers and climate scientists to discuss how to tackle issues around water use and scarcity.

It seems likely that the best solutions will be found by combining old and new knowledge, rather than dismissing one in favour of the other. For instance, parallel to the Cordillera Blanca is the Cordillera Negra (“black mountains”), which faces the Pacific Ocean. Without the benefit of glaciers, the ancient inhabitants of this area learned to harness rain water to see them through the dry season.

These pre-Colombian cultures instigated millennia-long engineering projects, resulting in large dams and reservoirs placed along the slopes of the mountains. These structures controlled water and soil erosion, feeding underground water deposits and providing water for crops and livestock.

An ancient dam in the Cordillera Negra. Kevin Lane., Author provided

Disuse over the last few centuries means that few are still functioning, but those that are, are a tribute to the ancient expertise. By contrast, modern concrete micro-dams have a functional life of 40 to 50 years, often curtailed by seismic activity to between 15 and 25 years.

Fortunately, plans are afoot to revisit these old technologies. Solutions rooted in respect for community and local knowledge, and allied to flexible modern engineering – such as better water retainment technology – are exploring ways in which we can shore-up the effectiveness of these ancient dams.

Throwing money and resources into engineering projects does not always guarantee success when trying to combat the effects of climate change and protect vulnerable communities. But the marriage of ancient and modern technologies offers promising solutions to the threat of water scarcity in Peru, and places like it all across the world.

———

This blog is by Cabot Institute member Dr Susan Conlon, Research Associate at the University of Bristol, and Kevin Lane, Senior Researcher in Archeology at Universidad de Buenos Airies. The article is republished from The Conversation under the Creative Commons licence. Read the original article.

Dr Susan Conlon

Irrigation pump. Image credit Wikimedia Commons.

From August 2015 to January 2016, I was lucky enough to enjoy an ESRC-funded placement at the Environment Agency. Located within the Water Resources Team, my time here was spent writing a number of independent reports on behalf of the agency. This blog is a short personal reflection of one of these reports, which you can find here. All views within this work are my own and do not represent any views, plans or policies of the Environment Agency.

Approximately 71% of UK land (17.4 million hectares) is used for agriculture – with 9.3 million hectares (70%) of land in England used for such operations. The benefits of this land use are well-known – providing close to 50% of the UK’s food consumption. Irrigated agriculture forms an important fulcrum within this sector, as well as contributing extensively to the rural economy. In eastern England alone, it is estimated that 50,000 jobs depend upon irrigated agriculture – with the sector reported to contribute close to £3 billion annually to the region’s economy.

It is estimated that only 1-2% of the water abstracted from rivers and groundwater in England is consumed by irrigation. When compared to the figures from other nations, this use of water by agriculture is relatively low. In the USA, agricultural operations account for approximately 80-90% of national consumptive water use. In Australia, water usage by irrigation over 2013/14 totalled 10,730 gigalitres (Gl) – 92% of the total agricultural water usage in that period (11,561 Gl).

However, the median prediction of nine forecasts of future demand in the UK’s agricultural sector has projected a 101% increase in demand between today and 2050. In this country, irrigation’s water usage is often concentrated during the driest periods and in the catchments where resources are at their most constrained. Agriculture uses the most water in the regions where water stress is most obvious: such as East Anglia. The result is that, in some dry summers, agricultural irrigation may become the largest abstractor of water in these vulnerable catchments.

With climate change creating a degree of uncertainty surrounding future water availability across the country, it has become a necessity for policy and research to explore which routes can provide the greatest efficiency gains for agricultural resilience. A 2015 survey by the National Farmers Union found that many farmers lack confidence in securing long term access to water for production – with only a third of those surveyed feeling confident about water availability in five years’ time. In light of this decreasing availability, the need to reduce water demand within this sector has never been more apparent.

Evidence from research and the agricultural practice across the globe provides us with a number of possible routes. Improved on-farm management practice, the use of trickle irrigation, the use of treated wastewater for irrigation and the building of reservoirs point to a potential reduction in water usage.

Yet, something stands in the way of the implementation of these schemes and policies that support them: People. The adoption of new practices tends to be determined by a number of social factors – depending on the farm and the farmer. As farmers are the agents within this change, it is important to understand the characteristics that often guide their decision-making process and actions in a socio-ecological context.

Let’s remember, there is no such thing as your ‘average farmer’. Homogeneity is not a word that British agriculture is particularly aware of. As a result, efforts to increase water use efficiency need to understand how certain characteristics influence the potential for action. Wheeler et al. have found a number of characteristics that can influence adaptation strategies. For example, a farmer with a greater belief in the presence of climate change is more likely to adopt mitigating or adaptive measures. Importantly, this can also be linked to more-demographic factors. As Islam et al. have argued, risk scepticism can be the result of a number of factors (such as: age, economic status, education, environmental and economic values) and that these can be linked to the birth cohort effect.

This is not to say that all farmers of a certain age are climate-sceptics but it does point to an important understanding of demography as a factor in the adoption of innovative measures. Wheeler et al. went on to cite variables of environment values, commercial orientation, perceptions of risk and the presence of an identified farm successor as potentially directing change in practice . Research by Stephenson has shown that farmers who adopt new technologies tend to be younger and more educated, have higher incomes, larger farm operations and are more engaged with primary sources of information.

Yet, there is one social pressure that future policy must take into account – friendly, neighbourly competition. Keeping up with the Joneses. Not wanting Farmer Giles down the lane knowing that you overuse water in an increasingly water-scarce future. This can be harnessed within a system of benchmarking. Benchmarking involves the publication of individual farm’s water use, irrigation characteristics and efficiency and farming practice. Although data is supplied anonymously, individual farmers will be able to see how they measure up against their neighbours, competitors and others elsewhere.

Benchmarking is used in other agricultural sub-sectors. A 2010 survey found that 24% of farmers from different sectors used benchmarking in their management processes. This is particularly evident in the dairy sector, where both commercial and public organisations use the methods as a way to understand individual farm performance – an important example of this would be DairyCo’s Milkbench+ initiative. In 2004, over 950,000 hectares of irrigated land in Australia, 385,000 hectares in China and 330, 000 hectares in Mexico were subjected to benchmarking processes as a mean to gauge their environmental, operational and financial characteristics.

The result is that irrigators would have the means to compare how they are performing relative to other growers – allowing the answering of important questions of ‘How well am I doing?’ ‘How much better could I do?’ and ‘How do I do it?’ Furthermore, this route can be perceived as limiting the potential for ‘free-riding’ behaviour within a catchment as well emphasise the communal nature of these vulnerable resources. We’ve all seen ‘Keeping up with the Joneses’ result in increased consumption – benchmarking provides us with an important route to use this socialised nudging for good.

————————————————————–

This blog is written by Cabot Institute member Ed Atkins, a PhD student at the University of Bristol who studies water scarcity and environmental conflict.

Ed Atkins

Read part 1 of this blog series Why is there a difficult absence of water demand forecasting in the UK?

Tag: irrigation

Peru’s ancient water systems can help protect communities from shortages caused by climate change

Modern day misfires

Ancient married with modern

Is benchmarking the best route to water efficiency in the UK’s irrigated agriculture?