Groundwater and the Water Cycle

Water is plentiful on earth, but only a small fraction is useable by humans. Water is found in the atmosphere, the clouds, in rivers and lakes, oceans, ice, within the ground, and in the human body. Over 70% of the world's surface is covered with water, but 97.5% percent of water is stored in oceans and is too salty to drink. The remaining 2.5% of water is disaggregated by source as shown in the chart below. The chart shows that groundwater comprises 30% of freshwater and most of the accessible freshwater on earth as glaciers and permafrost are not accessible.

Also check out these videos for a quick review of groundwater basics:

Groundwater is classified into renewable groundwater and non-renewable or fossil groundwater stores. Renewable groundwater. According to the FAO, renewable water resources “...represent the long-term average annual flow of rivers (surface water) and groundwater” while non-renewable water resources are “...groundwater bodies (deep aquifers) that have a negligible rate of recharge on the human time-scale and thus can be considered non-renewable.” The volume of groundwater that includes renewable and fossil groundwater has been estimated at 8-10 million cubic kilometers, or 98-99 percent of the total volume of liquid freshwater. In contrast, lake volume is less than one percent. However, the total groundwater volume is about one percent of the total volume of water available on Earth, which includes oceans. While this is the case, it is critical to note that most groundwater volume is fossil groundwater - only 10,000 billion cubic meters (10,0000 cubic KM) are renewable.

The image below from the USGS visualizes what is meant by renewable and non-renewable groundwater sources. Renewable groundwater existing in “unconfined” aquifers and are recharged in days or years. Confined aquifers, however, are less easy to both recharge and access as they are located beneath confining beds and water represents centuries or millennia of recharge.

Groundwater recharge and discharge vary spatially geographically and is highly dependent on climate. The integrated management of groundwater often requires “ thinking beyond the aquifer ” on the spatial and sectoral context. The primary source of natural groundwater recharge occurs when rainfall falls on the land surface, infiltrates into the soil, and then moves through the pore space down into the water table . Of the total precipitation that falls, only 22 percent of the rainfall is converted into blue water that consists of surface water and groundwater. The groundwater component of the blue water flow ranges from 25 percent to 33 percent. The nearby maps show the average annual precipitation and annual diffuse groundwater recharge per year.

Source: Doll, Fiedler(2008)

Groundwater discharge is conveyed

primarily through springs or streams, but there is a small portion that is conveyed into the ocean or abstracted from wells in dry climates.

The table displays groundwater discharge by climate.

Climate Region	Mean Depth (mm/year)	Groundwater Discharge (KM3/YR)	% Of Global Total
Subarctic	40	~6,000	52
Humid Temperate	30-150
Arid	10	~200	2
Dry Tropical (Semi Arid)	20-30
Humid Tropical	200-320	~5,800	48
Equatorial	600
Equatorial and Mountainous	700
Total	90	~12,000	100

In arid areas, groundwater is a significant part of the water cycle. 30 percent of the Earth is covered with arid and semi-arid regions, with groundwater being a permanent water source. The area suffers from low and scarce rainfall where recharge is less than 10 mm/year. As such, recharge is very localized and less widespread. Recharging the aquifer is done via local runoff and, to certain extents, percolation via irrigation rather than direct precipitation. On the other hand, groundwater is less likely to contribute to streamflow since streamflow is ephemeral and erratic. However, groundwater flow is commonly evaporated in shallow water tables that are found in closed depression. In some regions, the “fossil” groundwater that really has negligible recharge but can be “mined” like oil.

It follows that groundwater is exploitable, but not all groundwater is exploitable. Groundwater is not an exploitable resource under the following conditions:

1. Water quality requirements are not met after treatment for its intended use.

2. It may not be economically or technically feasible to extract groundwater.

3. Groundwater extraction may not be permitted due to the protection of the ecosystem or prevent land subsidence.

Groundwater Use

Groundwater is the primary source of drinking water for over half the global population and is also a critical irrigation source: groundwater is the water source for roughly 40% of global irrigated areas, supporting around 13% of food production globally and over 40% of irrigated food production ( CGIAR 2017). As such, groundwater is a key contributor to household and food security in semi-arid and arid countries, allowing communities and farmers the ability to produce food during periods of drought and to expand and diversity cropping choices and locations. The volume of water extracted is greater than any raw material extracted from the Earth: the volume of groundwater abstraction exceeds oil abstraction by 200 times.

In many ways, technology has also helped created the groundwater problem as well by new and cheaper ways to extract water from the ground and drill deeper. Sustainable groundwater supply is threatened by over abstraction and pollution. Over abstraction (see figure below from CGIAR 2017) is most prevalent in South Asia. Groundwater depletion has severe long-term consequences, most notably a potential lack of groundwater supply for irrigation in arid regions. As groundwater tables fall, the costs associated with pumping groundwater also increase, leading some farmers to be unable to access the resources from a cost perspective even though some water may remain in the aquifer.

The chart below shows the sustainability of water withdrawals in the MENA region , including for groundwater. As shown, unsustainable groundwater withdrawal is prevalent in much of this region.

The interactive tool below, developed by IWMI, is one modeling effort to help understand sustainable groundwater abstraction levels globally.

Groundwater management is a key concern globally and requires integrated groundwater management approaches (see extensive open book ).

The MENA region is one of the most water-stressed region in the world and continuing climate variability and climate change coupled with growing demands and pollution threaten the sustainability of the resource.

Mashreq region

Although there are many definitions of the Mashreq region, some of the initial countries of focus include Iran , Iraq,Jordan, Lebanon , Syria and Turkey.

Explore alternative estimates of the population distribution of the countries of the region by clicking on the following interactive graphic.

Turkey and Iran followed by Iraq have the highest population and growth in the region.

Many of these countries are also rapidly urbanizing as shown below.

However, many countries such as Syria, Lebanon, and Turkey have a high proportion of their land under agriculture with high agriculture water use.

Also explore the population pyramids of these countries in the past, present, and future interactively at these links: Iran , Iraq,Jordan, Lebanon, Syria and Turkey.

The formal economy of the region is concentrated in the urban areas as shown in this gridded GDP map.

These countries have seen very varied per capita GDP growth especially in recent decades (source: World Bank).

While the overall MENA (Middle East and North Africa) region is known to suffer from shortage of water due mainly to the climatic condition prevailing all over the region, the Mashreq suffers relatively less by benefiting from a milder and wetter climate compared to the other countries and is comparatively the richest in water resources in the MENA region.

The main permanent rivers in the Mashreq are the Tigris and Euphrates that has faced significant regional challenges in being a transboundary basin. Climate change, growing demands, and economic growth are adding to the water stresses in the region and the countries of the region are exploring new approaches to improve the management of this scarce and critical resource.

Disruptive Tech

There are numerous technologies that are evolving at a rapid pace - these can be “disruptive” depending on how these are used and are revolutionizing all aspects of development. Disruptive technologies can be classified into three broad types depending on purpose, as shown in the graphic below. Disruptive technologies hold great promise to fill data and knowledge gaps associated with groundwater quantity, quality, and use in the Mashreq region. This section first discusses the types of disruptive technologies that may be useful in this space - across disruption to data and analytics; manufacturing and operations; and stakeholder interactions - and then takes a deeper look at these technologies for groundwater specifically.

“Disrupting” Decision Making: How we gather, analyze, access, and visualize information:

An exciting range of technologies are emerging to help us disrupt the “data value chain” from datainformationknowledge decision support to make better evidence-based decisions. Inexpensive in-situ sensor networks (leading to an Internet of Things (IoT) approach) and field surveys and reporting are complemented by new “eyes in the sky” with satellite and drone earth observation power to help use better gather data and integrate with an increasingly digitalized economy. Improved telemetry, open data, cloud storage and analytics services, and distributed ledger (Blockchain) approaches to disrupt trust concerns are transforming the way this data is managed and analyzed using big (including geospatial) data processing, enhanced use of online modeling, machine learning and other Artificial Intelligence (AI) techniques. Access to these data is being revolutionized using Application Programming Interfaces (APIs), data and mapping standards, and innovative interactive data visualization. These can then be accessed using a range of platforms including portals, mobile Apps, and networked smart hardware at the user end (from smartphones, tablets, and computers to augmented/virtual reality devices.

In groundwater, these have the potential to help create new decision support tools for planning and operational monitoring and management of the invisible resource.

“Disrupting” Production: How we create, assemble, and supply products:

Increasing automation is helping us rethink the way products are made and distributed. Innovative technologies such as 3D printing or additive manufacturing has the potential to completely disrupt the location and methods of production and construction across sectors. A new generation of AI-powered robots has the potential to change the nature of work in several sectors. Automated transport has the potential to disrupt the way people and goods are moved around by driverless cars, trucks, ships, and unmanned aerial vehicles (UAVs). The use of advanced materials, nanotechnology, biotechnology, batteries, renewables, and other innovative manufactured products can help lower costs and improve performance across a range of development sectors.

For groundwater, these include new approaches to reducing demand, reducing evaporative losses, improving managed aquifer recharge, and how we monitor water systems (e.g. using 3D printed housing to reduce costs).

“Disrupting” Interactions: How we connect and work together:

This new world of disruptive technology is changing the way we all interact with each other, leveraging the economies of scale that comes from platforms that connect us. This includes enhancing the use of social networks facilitated by increasingly available digital connectivity, crowdsourcing ideas and financing, as we move to a sharing economy that encourages peer to peer platforms for collaborative consumption. Supply chains facilitated by blockchain have the potential to cut out many middlemen to improve efficiencies. A new generation can be part of the maker movement with do-it-yourself technologies in technology incubators. Digital ID and digital finance have the potential to change governance and spur financing innovations across the economy.

In groundwater-related areas, this could help change the way virtual learning and capacity-building is done, and the way in which relevant e-governance initiatives could be leveraged to better connect people to learn from, and contribute to, global good practice on sustainable groundwater management.

The real power of disruption comes in the way these technologies are combined and deployed to solve development challenges. They have tremendous potential in changing the way development happens around the world and bring in concerns that need to be effectively managed. Groundwater management could benefit tremendously from reimagining information, institutional, and investments aspects. Disruptive technologies show great promise in supporting water security in large basins such as the Tigris and Euphrates.

The countries of the Mashreq are rapidly increasing their access to the internet and mobile connectivity that can be leveraged to use digital technologies for groundwater management.