Pipelines to Combat Water Shortages

Transporting drinking water from water-rich regions to areas where it is scarce is the driving motivation behind the construction of long-distance water pipelines, which have a very long tradition. Numerous examples from antiquity show how water was transported over several hundred kilometers from the extraction site to consumers. Hans Mehlhorn and Matthias Weiß provide an impressive overview of both historical and modern long-distance water supply systems in Europe, the USA, and China [1].

Historical Long-Distance Water Supply System

Some of the most renowned ancient pipelines are the 11 aqueducts that supplied the ancient city of Rome with water. This network spanned a total of 500 km, with the longest single distance reaching 90 km. Perhaps the best-known Roman aqueduct in Germany is the Eifel Aqueduct, which supplied water to what is now Cologne [1]

For over 150 years, the First Vienna Mountain Spring Pipeline has been operational, transporting 220,000 m³ of water daily from the Rax, Schneeberg, and Schneealpe regions to Vienna. In 1910, it was followed by the Second Vienna Mountain Spring Pipeline, which spans 180 km and carries up to 217,000 m³ of water daily from the Hochschwab region through Lunz am See, Gaming, Scheibbs, Wilhelmsburg, and Rekawinkel to southern Vienna [4]. This video showcases the journey of Vienna’s water from its various sources down to the valley:

The water transported through these two pipelines originates from more than 70 individual springs.

California Aqueduct
Image: Entoptic Studios /Adobe Stock

0th-Century Megaprojects

The California Aqueduct, a vital component of California’s State Water Project (SWP), transports water from the Sacramento-San Joaquin Delta to the San Joaquin Valley and Southern California.

Stretching 444 miles (approximately 715 km), the California Aqueduct (officially the Edmund G. Brown California Aqueduct) was constructed following a $1.75 billion bond approved by voters in 1960. Beginning at the Harvey O. Banks Pumping Plant, it runs parallel to Interstate 5, heading south to the Tehachapi Mountains [5]. To traverse this mountain range, a significant portion of the water is pumped to an elevation of about 878 meters. The SWP includes additional aqueducts and pumping stations and connects to the federal Central Valley Project (CVP) water system, which encompasses the Delta-Mendota Canal. Since 2012, a direct link between these two pipelines has enhanced water supply flexibility for cities and agricultural irrigation [5].

California’s aqueducts are open raw water channels (see image). Water designated for urban use is treated to drinking water standards only at its destination.

South-North Water Transfer Project,
Image: Pieceofmetalwork - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=148947179

The largest water transfer project in history is found in China: the South-North Water Transfer Project. This system, consisting of canals and tunnels totaling approximately 3,500 km, supplies water from the south to the arid but densely populated northeast. The most significant route is the central one, which supplies Beijing and began operations on December 12, 2014.

In January 2024, China launched a follow-up project: a water transfer tunnel that will direct water from the Three Gorges Reservoir region to the Hanjiang River, a Yangtze tributary, to increase the water supply to Beijing.

Major Long-Distance Water Supplies in Germany

Germany’s long-distance water supply systems are primarily located in Saxony, Thuringia, Saxony-Anhalt, Hesse, Baden-Württemberg, and Bavaria. Table 1 provides data on the largest long-distance water supply companies in Germany.

Recent or Newly Completed Projects

Some German water utilities reached their capacity limits during the dry summer months of 2018–2020. To prevent such shortages in the future, new long-distance pipelines have been or are being constructed, with some running parallel to existing lines.

One example is the 42 km pipeline by Fernwasser Elbe-Ostharz (FAO), which transports drinking water from the Rappbode Reservoir in the Harz region to the Halle area. Completed in 2022 after 14 years of construction, it exemplifies this approach.

The Neue Riedleitung is a new pipeline supplementing an over-50-year-old line that delivers water from the Hessian Ried to Frankfurt. This development has been previously discussed.

The Gelsenwasser AG is expanding its supply infrastructure in East Westphalia by constructing new pipelines between Beckum and Rheda-Wiedenbrück. These lines will connect the Gelsenwasser network to that of the Vereinigte Gas- und Wasserversorgung GmbH (VGW), a wholly-owned Gelsenwasser subsidiary. Construction on a section between Beckum and Oelde is set to begin in 2026, followed by the Wiedenbrücker pipeline from Oelde to Rheda-Wiedenbrück, expected to be operational by 2028.

In autumn 2024, an announcement about an additional 18 km pipeline from Varensell to Bielefeld caused a stir. This project would supply Bielefeld with water from the Ruhr River basin. However, its realization is still uncertain.

Definition of Long-Distance Water Pipelines

According to Haakh [1], long-distance water pipelines transport large quantities of drinking water through large-diameter pipes over significant distances. The guidelines from the Free State of Thuringia [2] suggest that the defining criterion is not necessarily the pipeline’s length but rather its function as a supra-regional main water pipeline, often crossing municipal boundaries.

Mehlhorn and Weißbach [1] outline three characteristics of long-distance water pipelines:

•A pipeline length exceeding 30–50 km between the source and supply area.

•Alternatively, the supply of larger cities requiring significant distances between water extraction and distribution networks (e.g., Hamburg, Frankfurt, or Munich).

•In most cases, long-distance water suppliers act as wholesalers, not operating local networks.

Table: Major Long-Distance Water Suppliers in Germany

Company	Service Area	Pipeline Network (km)	Water Source	Average Delivered Amount
Zweckverband Landeswasserversorgung (LW)	Baden-Württemberg and Bavaria, about 250 cities and municipalities, around 3 million people	768 km, of which 335.6 km are main long-distance pipelines	Groundwater storage Donauried, Buchbrunnenquelle (Swabian Alb), Danube	90 million m³/a
Zweckverband Bodensee-Wasserversorgung (BWV)	About 320 cities and municipalities, including the Stuttgart region, around 4 million inhabitants	Over 1,700 km	Lake Constance	135 million m³/a
Ruhrverband/Wasserwerke Westfalen	Southern Münsterland, central and eastern Ruhr region, northern Sauerland	Unknown	Reservoirs, Ruhr and groundwater	99 million m³/a
Wasserversorgung Bayerischer Wald	Seven districts, a total of around 5,500 km², 225,000 inhabitants	850 km	Reservoir Frauenau and groundwater	Approx. 25 million m³/a (estimated)
Fernwasserversorgung Elbe-Ostharz	Central Germany between Harz and Elbe, from Halberstadt to Altenburg (Thuringia)	750 km	Reservoirs (Rappbode), bank filtrate from the Elbe, Spree water	80 million m³/a
Fernwasserversorgung Oberfranken	Upper Franconia, about 400,000 inhabitants, part of the northern Bavarian network system	500 km	Reservoir Mauthaus – Ködeltalsperre (80%), 20% from the water supply of the Franconian economic region	13 million m³/a
Hessenwasser	Rhein-Main region with 2.4 million inhabitants	337 km	Groundwater, infiltrated groundwater (treated Rhine water)	110 million m³/h
Gelsenwasser AG	Direct supplier and further distributor: Ruhr region, Münsterland, Rhineland, and East Westphalia-Lippe	Unknown	Water from the Ruhr catchment area	205 million m³/a

Lake Constance Water Supply:
Rising pipes used to pump water from the intake structure to the Sipplinger Mountain, 310 meters higher.
Image: Bodensee-Wasserversorgung

References:

[1] H. Mehlhorn, M. Weiß: Fernwasserversorgung und Verbundsysteme in der Wasserversorgung. gwf Wasser|Abwasser Jubiläumsausgabe 2009, pp. W74–W94.

[2] F. Haakh, HB. Horlacher (2023): Planning, Construction, and Operation of Long-Distance Water Pipelines. Springer Vieweg, Berlin, Heidelberg.

[3] Thuringian State Office for Environment, Mining, and Nature Conservation (TLUBN): Guidelines for the Approval of Long-Distance Water Pipelines. April 2020.

[4] Vienna History Wiki

[5] Entoptic Studios/Adobe Stock (California Aqueduct).