By Joseph Kyalo Makau – EM42 Participant from Kenya
‘Is it safe? Can I drink the tap water? Is it treated? Have you ever been reluctant to drink tap water anywhere, be it in your home or a place of visit? Yes, of course, it is common that many people express doubts on the safety of drinking tap water. This is mainly because of the health and environmental risks associated with unsafe drinking water. Well, in Germany the safety standards of drinking water are very stringent and because of this, tap water is one of the safest and most controlled beverage/food products in Germany. As per the DIN 2000 Central drinking water supply guidelines, drinking water in Germany has to be appetising and tempting, colourless, clear, cold, odourless, with a perfectly fresh taste. But how possible is it to meet all these quality criteria? It is not so simple, especially when water quality is highly influenced by exogenous and mediating factors like drainage basin land use/ cover, soil factors, climate, physical and chemical properties and processes, biotic factors and their ecological interactions. In pursuit of understanding this intricate yet very vital issue of water supply management and monitoring the EM42 course participants embarked on a 2 days expedition to Neunzehnhain Ecological Station.
Thursday the 25th day of April 2019, time 10:30 AM, a bright sunny day in the colourful springtime, in front of the CIPSEM conference room, Dr Anna Görner, the managing course director, checks out on team’s readiness for the exciting adventure in the Ore Mountains. Packed lunch, check, warm clothing, check, mobile tour guide system, check. ‘I wish you an exciting excursion ahead, please note that there is limited network connectivity on the mountains and you need to make all your important communications before you leave Dresden,’ the Director advised as she saw us off to the bus. How can we survive without phone connectivity, there is no WIFI at all! The participants agonised. Nevertheless, the matter of phone signal never dampened the excitement of the team to explore the sites and scenes of Germany outside the conference rooms. Hop on the bus, bye Dresden and off we went.
With all energy and team cohesion up high in the bus, I couldn’t fail to appreciate how excursions brought out the beauty of diversity when over twenty nationalities with diverse backgrounds are converged by a common goal of achieving a sustainable environment for all in the present and future generations. We all cheered up through the 80 km journey south-west of Dresden as the bus’s incredible horsepower cruised us up the hilly terrain from the lowlands of Dresden at 140m above the sea level to the cold, forested mountainous range of Pockau-Lengefeld at over 420m. It was breathtaking to see large scale well-manicured yellow blooming rapeseed contour farms and green meadows punctuated by stripes of mono-culture beech and coniferous plantations grace the landscape with the bright blue sky horizons intercepted by the high rise rotating wind turbine rotors.
At the Neunzehnhain Ecological Station we were warmly welcomed by Dr Paul Lothar who gave us a brief on the establishment and goals of the ecological station. Back in 1959, the Zoological Institute of the University of Leipzig established the station as a Hydrobiological Laboratory that was later in 1968 transferred to the Department of Hydrobiology at the TU Dresden as a field office. Since 1991 the station has been an operating as an independent unit of the Faculty of Environmental Sciences of the TU Dresden, closely collaborating with the Institute of Hydrobiology and the Department of Hydrosciences. Due to the important role the ecological station plays in the management of water supply in Saxony, the working group limnology of dams of Saxon Academy of Sciences Leipzig has been housed in here since 1976. With over 4 decades of experience at the station since 1975, Dr Paul underscored the importance of long-term ecological monitoring of water quality as a function of the structure and land-use of the catchment area, internal mass transport and transformation processes mediated by sunlight, temperature and biological manipulation for sustainable management of low mountain streams and dams.
In the two days excursion, we visited the 3 million m3 Dam Neunzehnhain II under a guided tour by the Dam Authority of Free State of Saxony and also the 22.4 million m3 Saidenbach dam. These two dams are part of the 3 dam system that was built at the end of the 19th century to supply industrial and drinking water to the city of Chemnitz. It was fascinating to walk through the 30m deep inspection tunnel under the Neunzehnhain II mega architectural dam wall that has state of the art technology installed for monitoring the dam wall stability, earthquakes and tremors. This monitoring is so important because high water volume curved gravity dams like the Neunzehnhain II and Saidenbach reservoirs have inherent risks of breaking due to water pressure exerted on the walls. It was because of this risk that the Neunzehnhain II dam built in 1911-1914 was rehabilitated to have an additional concrete reinforcement layer and waterside sealing wall in 1996 to 2000. Dam siltation is another challenge for water reservoirs management that, if not well controlled, impairs water quality, reduces dam capacity – besides the high cost of desiltation and maintenance. To mitigate this, the two dams have check dams/pre-dams at the drainage channels that act as silt traps through sedimentation. However, siltation remains a major challenge for reservoirs whose drainage area has land uses that increase soil erosion such as agriculture in the case of Saidenbach reservoir.
The waters at the Neunzehnhain II appeared brownish in colour attributable to the dissolved organic compounds from the surrounding protected forest drainage basin. On the other hand, the Saidenbach water appeared green due to the presence of phytoplankton like the green algae, an indicator of nutrients overload from the 70% agriculture land use in the catchment. Comparison of these two reservoirs was a classic example of how catchment land use affects water quality and hence the need to protect the catchment as a pollution control measure.
At the Saidenbach dam, the participants were introduced to water monitoring technologies by Dr Paul. One of the key technologies we experienced was the use of BBE FluoroProbe for monitoring biological and biophysical parameters like quantities of phytoplankton (diatoms, blue and green algae), water depth and temperatures. Monitoring these parameters is critical because they are direct and indirect indicators of the state of the bio-physico-chemical characteristics of the water reservoir such as water thermo-stratification, mixing, nutrients flow, PH, dissolved oxygen and others.
As I pen off this post, I would like to acknowledge Dr Paul’s charisma on sharing with us so much knowledge and experience on the interface of quality water supply with reservoir management, catchment protection and technologies of water monitoring in the context of a changing environment, climate and water demands. Much thanks to the Dam Authority of Free State of Saxony, Tamara Karp of the CIPSEM for being an inspirational team leader during the expedition. Special thanks to each and every EM42 participant for making the excursion so lively that nobody remembered to worry about the phone signals. Did I almost forget about the mouthwatering dinner and lunch that CIPSEM was so kind to invite us, in particular, the dinner and after dinner fun-moments at the quaint, chateau-style Villa Wilisch hotel, an oasis of tranquillity in the secluded forest enclaves of Amtsberg municipality.
Photos by Joseph Makau (Kenya), Haili Zhou (China) and Hasmik Barseghyan (Armenia)