Water scarcity

Water scarcity is currently on everyone's lips. Whether online, on television, in newspapers or at conferences, almost everyone recognizes the problem and many people are talking about it. What is missing are concrete solutions or ideas for tackling water scarcity: approaches to what can be done on both a small and a large scale.

Aquifers

Aquifers are vast groundwater reserves connected underground. They occur in different sizes throughout the world. These reservoirs feed, for example, the springs of oases in the Sahara. Gaddafi's solution was to build a huge pipeline to use this groundwater to counter water shortages in cities. All these aquifers are tapped to obtain drinking water, irrigate fields or supply animals. One of the world's largest aquifers is the Ogallala Aquifer in North America. It extends from South Dakota on the Canadian border all the way south to Texas. Many of these groundwater reservoirs are overexploited. This means that more water is withdrawn than can flow back in. Climate change is part of the problem.

Africa

We have long known that water is scarce in Africa and is becoming scarcer. Lake Chad, on the southern edge of the Sahara, is a lake with no outflow and has long supplied drinking water to the surrounding countries. The problem is that the lake has lost around 90 percent of its area over the last 60 years. The remaining water is no longer sufficient to adequately supply people and animals. As a result, the fish are smaller and farming is barely possible without water. People flee, trying to reach Europe or heading south in search of land with enough water. The Nile has always supplied Egypt with water. Water scarcity is making itself felt here too. Groundwater levels are falling, and the Nile can no longer replace the water withdrawn. Even today, there is not enough water to irrigate all the land. Ethiopia is now building the Grand Ethiopian Renaissance Dam on the upper Nile to generate electricity and irrigate its own fields. Both Sudan and Egypt are protesting; conflict is inevitable here too.

Asia

The Middle East has always suffered from water shortages. Since oil and gas were discovered, the region's solution has been to produce drinking water from seawater. This requires a great deal of energy, but energy is abundant and inexpensive there. Farther east, in Isfahan, Iran, the river that has supplied the city with water for centuries is reduced to a trickle for several months every summer. The photograph on the left shows the Khajoo Bridge; what is missing is the water flowing beneath it. Farther north, in Central Asia, a great deal of water is used to irrigate cotton fields. This causes severe water stress in some countries. Groundwater levels are falling and more and more wells are running dry. Without water from these wells, conventional farming is virtually impossible.

Water is also scarce in China, and rivers are drying up. The large hydropower plants in western China, in Sichuan province, are generating significantly less electricity this summer because of the water shortage. FAZ.net

China and India have already had armed confrontations over the waters of the Brahmaputra. The river rises in China, where it is called Yanlung Zangbo Jiang. China is considering diverting this water eastward for its own use before it flows south across the border into India.

North America

We also repeatedly hear about water shortages in parts of the USA. Arizona, Utah, Nevada and California, to name just a few. California is currently being hit particularly hard. The Metropolitan Water District of Southern California supplies drinking water to around 19 million people. It declared a water emergency back in April this year, before summer had even begun. It was decided to prohibit watering gardens and washing cars. The Colorado River rises in the Rocky Mountains and empties into the Sea of Cortez in Mexico. (At least, it used to.) It supplies drinking water to 40 million Americans and irrigates around 20,000 square kilometers of farmland on its journey south. The well-known lakes, Lake Mead and Lake Powell, north of the Hoover Dam near Las Vegas, are reporting historically low water levels. The photograph shows how low the water level currently is. The water used to reach up to the dark rock. Half of the USA's fruit and vegetables are grown in California's Central Valley. The water crisis has reached this area too. Farmers have to cut down some of their almond trees because the shortage has become so severe that they can no longer irrigate all the trees. California produces 80 percent of the world's almonds. Virtually no water reaches the mouth of the Colorado anymore. Most of the people living in the delta, who long lived with and depended on the Colorado, have moved away. The Rio Grande, on the border between the USA and Mexico, is dry over long stretches this summer. At least refugees from the south can now reach the USA without getting their feet wet.

Europe

This summer of 2022, climate change and its associated problems are being discussed throughout Europe. Persistent dry conditions and the resulting drought are visible everywhere. Rivers and lakes are drying up, forests are burning, and many fields are bone-dry. Crop failures follow because plants do not develop as usual in the dry conditions. Restrictions are now being imposed. Swimming pools may no longer be filled, gardens may no longer be watered, and water emergencies have been declared in many places. A major challenge is that many communities no longer have their own drinking water because of the drought. These places now have to be supplied with drinking water by truck.

A selection of reports and news items from June to August 2022

- FAZ - Die Zeit - German Environment Agency - SZ - Arte - National Geographic - Washington Post - CBSnews

An unrealistic solution

As described elsewhere, a conventional water softener or descaling system needs salt to soften water. These systems must be regenerated regularly. Statistically, a family of four in Germany consumes 200 to 250 m³ of drinking water a year. Conventionally softening this water (20°dH) uses around 250 kg of regeneration salt and 10 m³ of water for regeneration.

Hardness 10°dH 15°dH 20°dH 25°dH Salt 125 kg 180 kg 250 kg 320 kg Wastewater 5 m³ 7.5 m³ 10 m³ 12.5 m³

If 10,000 four-person households replaced their softening systems or took them out of service, around 20,000 m³ of drinking water could be saved each year in Munich (20°dH), for example.

Extrapolated across Germany, this would mean: There are around 16 million single-family homes in Germany. Let us assume that 20 percent have a water softening system. If this 20 percent, or 3.2 million households, chose another option, we could save 3.2 million times 7.5 m³, or 24.5 million m³ of water, at an estimated average hardness of 15°. At the same time, around 1 million metric tons less salt would enter the wastewater.

Why is this approach unrealistic? Everyone involved throughout the water-softening supply chain earns very good money. Most of those involved therefore see no reason to give up this excellent business.

We have more ideas: see Saving water.

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