Millennium heavy rain - Hamburg Wasser invests 1.4 billion euros
In the face of climate change with increasingly frequent heavy rains, like the one that occurred last Thursday, Hamburg's municipal water supplier plans to invest around 1.4 billion Euros in its infrastructure by 2027. About a billion Euros of this will go towards the sewage sector and its facilities and the sewer network, while 400 million Euros will be allocated to the drinking water network, said Gesine Strohmeyer, Hamburg Wasser's commercial manager, on Friday. The spokesperson for the management, Ingo Hannemann, stated that studies have shown clearly that especially in the winter half-year, more rain will fall and in the summer, frequent heavy rains should be expected.
Rains as intense as in the Ahrtal disaster
Last Thursday saw extreme rain and flooding in Hamburg. For instance, approximately 60 liters of water per square meter had fallen in the Stadtpark within two hours and 40 minutes, but what was particularly dramatic was the 47 liters that had fallen in just 20 minutes, Hannemann said. This almost reached the intensity of the rainfall during the Ahrtal disaster about three years ago. During the subsequent flood disaster, 135 people lost their lives. Hamburg was fortunate to have escaped unscathed last Thursday. However, "our statistics say that this was a rain event that occurs only once in 10,000 years", Hannemann added.
Hamburg Wasser had surprisingly good earnings in the previous year. With a turnover of around 630 million Euros, the company generated a surplus of nearly 110 million Euros, as Strohmeyer stated. This was an increase of around twelve percent. The reasons for the significantly increased profit were, among other things, structural savings and postponed projects, above all, lower repayments due to rising interest rates. While the city received a profit of around 44 million Euros from the sale of drinking water, the surplus from the sewage business amounted to around 65 million Euros and went into reserves.
Water consumption decreased despite increasing population growth
Water consumption in Hamburg reportedly decreased by around one million cubic meters to 114 million cubic meters in the previous year. The per capita consumption of the approximately 2.2 million people supplied with water decreased from 111 to 106 liters per day. "The year 2023 was again a thrifty year", Strohmeyer said - and added: "It was a year in which we had consumption savings, despite population growth in Hamburg." On the other hand, the development in the wastewater sector was quite different. The amount of wastewater treated in the sewage works increased from around 153 million cubic meters to almost 170 million cubic meters of wastewater. The cause was the weather. "It was really the enormous rain", Strohmeyer said.
The Hamburg drinking water network is reportedly about 5300 kilometers long, while the sewer network is about 6000 kilometers long. According to Hannemann, around 250 kilometers of the approximately 120-year-old masonry pipes need to be repaired point by point. To make this possible, replacement channels have been built in recent years. "Unlike in road traffic, we cannot simply completely shut down our sewer pipes to work on them", Hannemann said. Long-term, a parallel operation is planned. This would increase the network capacity by up to 9000 cubic meters - as much as in 30,000 standard rain barrels.
20 million Euro special program for U-Bahn construction
Due to the construction of U-Bahn line 5, Hamburg allegedly sets up a special 20 million Euro program according to its own statements. Specifically, it is about strengthening the bypass roads in the vicinity of the construction sites in Winterhude and Hohenfelde, so that there are no pipe ruptures when the traffic there significantly increases. Similar works have been carried out in Barmbek and Bramfeld in the past year. Hannemann emphasized: "What we need now are quick approvals."
In light of future predictions of heavier rainfall during both winter and summer seasons due to climate change, the sewage sector in Ahr valley is set to receive a significant portion of Hamburg Wasser's proposed investment of 1.4 billion Euros by 2027. This intense rainfall was evident in last Thursday's storm, which saw Hamburg experiencing nearly as much rainfall in 20 minutes as during the Ahrtal disaster three years ago.
Despite the significant investment required for infrastructure updates, Hamburg Wasser reported a surplus of nearly 110 million Euros last year, with good earnings in the drinking water sector contributing significantly to this figure. The decreased water consumption amongst the city's growing population, mainly due to thrifty practices, also played a role in these positive earnings.
Over the years, the sewer network in Hamburg has expanded to around 6000 kilometers, necessitating repairs to aged masonry pipes, specifically around 250 kilometers of 120-year-old pipes. With replacement channels constructed for maintenance, long-term plans involve parallel operations to improve network capacity by up to 9000 cubic meters, equating to 30,000 standard rain barrels.
Concerned about the increased construction traffic associated with U-Bahn line 5, Hamburg has allocated a 20 million Euro special program to strengthen bypass roads and prevent any potential pipe ruptures or flooding. Similar works have been executed in previous years in Barmbek and Bramfeld, with approval processes being prioritized for future construction sites.
