Groundwater management: steps towards a sustainable future
The last 20-40 years have witnessed a massive boost in the use of ground-water resources for irrigation across the globe.
The agricultural sector is the largest and, presently, one of the least efficient users of water. Irrigated agricultural practices account for roughly 70% of global water usage, and over 40% in many OECD countries. The relationship between contemporary farming and water is, therefore, one of reliance. Without water, farms will simply not be able to operate at current levels of productive efficiency and economic success.
This reliance and consequent vulnerability to water-loss also needs to be considered in relation to climate change. Projections indicate that climate change will cause greater numbers and intensity of extreme weather events, such as drought and floods. Models also predict that there will be increased fluctuations in precipitation, decreasing the stability and reliability of surface-water supplies. When combined with the pressures of population growth, it is clear that farms will need to adapt to operating with decreased water resources.
A recent trend in line with the search for reliable water sources has taken the agricultural sector underground. The last 20-40 years have witnessed a massive boost in the use of ground-water resources for irrigation across the globe. Irrigated agriculture is the largest extractor and consumer of groundwater, with large groundwater dependent agroeconomies developing in many countries.
It is important to point out that there are a number of known benefits in the use of groundwater within agriculture. Firstly, groundwater resources are usually under the direct control of the farmer. This means that water is available directly on demand for differing needs, enabling farms to be adaptable and flexible. Groundwater is often found in close to proximity to its point of use. It is low cost and scaleabale, making it a very appealing commodity for farmers across the world.
The availability and immediacy of water provided from groundwater resources has contributed greatly to increasing food security across the globe. By ensuring the accessibility of water at critical times in crop-growth cycles, groundwater is able to mitigate the impacts of natural hazards on crop yields (i.e. surface-water drought).
However, for all its benefits as an immediate and accessible resource, there are key issues that need to be flagged up in relation to its increasing global utilisation.
The world demand for food is expected to rise by 60% – 100% by 2050. Growing demand, along with increasing urban sprawl, means that farmers in many regions will have to deal with increasing competition for water from non-agricultural sectors. Furthermore, as an open access resource, groundwater is susceptible to the ‘tragedy of the commons’, where individual short-term benefits clash with long-term communal decisions.
Each of these concerns can be linked back to the overarching issue of increasing demand versus decreasing supply. If replenishment rates of ground water resources cannot meet abstraction rates then, again, farms will have to adapt to operate with lower amounts of water. Consequential issues such as aquifer salinization and land subsidence must also be taken into account when assessing the exploitation of groundwater.
However, the future for farmers in relation to ground water most definitely does not have to be negative. There are a number of beneficial opportunities for the agricultural sector in relation to groundwater, as long as appropriate management is implemented on local and national scales.
The challenges that lie ahead for the agricultural sector in relation to groundwater management are both extremely complex and locally diverse. New technologies, such as drip and pivot irrigation, are being championed within the sector as they can increase farm water-use efficiency whilst maintaining, or even increasing, crop yields. Economic incentives can also be adopted to promote sustainable practices in farming, helping farms remain economically viable whilst also promoting efficiency.
For farmers, therefore, it is key to understand that sustainable practices need to be implemented for long term success. Although the short term economic benefits of resource exploitation may be appealing, the consideration of future pressures, such as climate change and population growth, indicate that sustainable practices are essential.
For policy makers, it is vital to recognise the need to promote the agricultural sector’s overall water efficiency, whilst reducing the sector’s impact on groundwater resources and, consequentially, improving its resilience to water shortages on local and national scales.