This fall, people from various walks of life came together to walk along the Danube, exploring her significance to the communities living along her banks and learning about the river's health. The walk was part of the first River Walk under the DANUBE4all project, which took place in Romania from September 18 to October 11, 2024.
The journey followed several key stretches of the Danube, beginning at the Black Sea, continuing to the confluence of the Jiu River, and concluding near the Serbian border. Along the way, participants visited specific landmarks such as the Iron Gates and several towns along the river, including Jurilova, Mahmuhdia, Tiganasi, Crivina, and Drobeta Turnu Severin.
Figure 1: Map for the Danube River Walk 2024
Joining Hands for River Health and Restoration
The River Walk was initiated and led by Li An Phoa, founder of Drinkable Rivers. Drinkable Rivers’ mission is to inspire people to act for a world with drinkable rivers, raising awareness and engaging inhabitants, experts, and policymakers living near the Danube river by creating experiences with the river. Li An emphasises "the need for rivers that are ecologically healthy to the point where we can drink directly from them”, highlighting how the Danube river family depends on this crucial watershed.
Figure 2: Li An Phoa and co-walkers engaging in conversations during the Danube River Walk
Pictures by Camille Janssen
A Typical Day During the River Walk
A typical day during the River Walk involved interactions with local people, including herders, fishermen, mayors, and farmers. The group trekked through the various ecosystems under high temperatures, taking citizen science measurements with children, and even cooling off in a canal, the Danube or the Jiu. Observing the landscape, they noticed, among others, irrigation canals, wildlife gathering near the river water, and the unfortunate presence of waste. Conversations flowed based on questions and topics raised by Li An, and most days concluded with a warm welcome and homemade meals offered by local hosts.
Figure 3: Walkers together with local host
Picture by Li An Phoa
The group on average covered distances of around 15-20 kilometers per day along the Danube, including stretches upstream of the Iron Gates Dam where the river broadened to nearly 5 kilometers in width. The expansive waters and scenic views, particularly around sunset, added a tranquil yet majestic atmosphere to each day’s journey.
Figure 4: One of the co-walkers looking at the flood plain (Week 2)
Picture by Camille Janssen
Citizen Science Measurements
The start of each day was marked by a citizen science water quality measurement, predominantly carried out together with children from local schools before the journey by foot continued. The purpose of these activities is to build and deepen the connection between communities and the river, raise awareness on ecosystem health, and advocate for healthy, drinkable waters.
Figure 5: Pictures taken during the citizen science measurement in Bechet
Pictures by Camille Janssen
Over the course of the walk, 331 children joined in total, taking part in a hands-on way for people to engage with the river, creating an atmosphere of discovery and environmental responsibility and representing schools and clubs along the river. They conducted tests on the pH, hardness, color, and smell of water, as well as the presence of E. coli bacteria, and studied fauna and water clarity.
Figure 6: Measurement locations along the Danube (indicated by the loop)
Original images from the Drinkable Rivers website
These tests allowed participants to gain insight into the river’s health and observe first-hand how these factors impact aquatic life and drinkable river water potential. Their participation not only enhanced the experience but provided invaluable data and enthusiasm. These children brought fresh energy to each session and each day, with new groups joining at various points along the walk. This citizen science element, aligned with the focus of the DANUBE4all project, encourages a vision of a healthier, drinkable Danube.
Figure 7: Citizen science measurement with local children
Picture by Maarten van der Schaaf
More on the gathered data
The water measurements were taken along the Danube river, tributaries, flood lakes, and one of tap water (groundwater) over the course of the 3-week walk, amounting to 15 measurements. These measurements were submitted to the online data platform of Drinkable Rivers and then analysed. The results were inspected for unusual peaks, and parameters such as pH, hardness, and electroconductivity were contrasted with what the participants perceived in the area, such as river features and the pleasantness of the surroundings.
One example of a parameter that demonstrates abrupt changes from upstream to downstream is the number of E. coli colonies grown from water sampled from the river (figure 7). E. coli is used as one of the indicators of water quality because the bacterium is found naturally in the intestines of humans and many animals, yet does not normally reproduce in rivers. It is therefore linked to waste matter, which can carry other harmful microorganisms. In order to be able to drink straight from the river water, it should not have any E. coli present, and very low levels are admissible in swimmable river water.
Along the trajectory of the Danube river and its tributaries, Cârna Lake (measured on the 4th of October) not only had the highest total E. coli colonies (153), but also the highest pH readings (sensor 9.96, strip 8.4), and the second highest nitrate level (10 mg/L, when the ideal range is less than 3 mg/L)). These high levels could be attributed to the surrounding landscape with animals grazing there, both sheep as well as geese. Cârna Lake, along with neighboring lakes, was once part of an extensive floodplain connected to the pulse of the Danube river. The floodplain has become increasingly isolated, due to the dyke between the Danube and the floodplain, as the surrounding land has been converted to farmland. The lakes functioned as fish ponds and rice paddies during the time of the regime.
Figure 8: E.coli levels
Another peak visible in figure 8 above is Drobeta-Turnu Severin (measured on the 11th of October). This location had the second-highest total E. coli colonies (103), high total hardness (425 mg/L, where 60 to 250 mg/L is ideal), and fairly high phosphate (0.6 mg/L, where less than 0.15 is ideal). In contrast to Cârna Lake, this measurement location was urban, with surroundings such as buildings, a bridge, a dam, and railway tracks, and the water was purported to have a slightly fishy smell. Engineered constructions such as dams disrupt the flow of the river and can have an effect on the balance of nutrients in the water, as can built-up areas alongside rivers which force run-off to flow directly into the river, pollution and all.
When considering the type of surroundings and the number of E. coli colonies counted (figure 8), farmland, followed by urban areas, had the highest average E. coli. Although the sample count is low, this suggests that water draining into the river from farmland and urban areas may be correlated to an unhealthy high increase in E. coli.
Figure 9: E.coli levels by surroundings
There are many more locations and parameters the measurements investigate, such as the presence of certain plants and animals, the color of the water, the amount of plastic seen in the river, and the shape of the riverbank. This set of measurements is the start, like a baseline study, which could continue to develop by other organisations to indicate patterns that might support similar results.
Figure 10: Plastic pollution measured
The Danube River Walk Continues
The Danube River Walk exemplified a powerful, community-driven approach to river conservation, blending science, education, and hands-on engagement with local people and places. For those inspired by the DANUBE4all journey, joining the Healthy Danube Network is an excellent way to connect with like-minded individuals dedicated to river health and sustainable practices. If you’re interested in organising your own river walk, please stay tuned to receive an instruction package (expected from 2026) or you can reach out to community@danube4allproject.eu for advice on creating impactful and educational events that engage your community and promote river conservation. Together, these efforts can contribute to a shared vision of protecting and revitalising the Danube and her tributaries / Europe’s rivers.
Furthermore, when joining the Healthy Danube Network, you can also get informed about how we will open a call for submissions to get a discount for joining as a Drinkable Rivers Citizen Science hub. The DANUBE4all project aims to engage many more people in taking these measurements, and will therefore sponsor half of the costs for 20 new Drinkable Rivers hub joining. As a Drinkable Rivers hub, you can take your own citizen science water quality measurements, engage the people in your area, identify priorities in your river, and showcase the state of the Danube river's health. The DANUBE4all project aims to engage many more in taking these measurements. If you are interested in becoming a Drinkable Rivers Hub in the Danube region, please express your interest here.
This article has been written by Anthonette Quayee, Sandra de Vries, Grace Saville, and Camille Janssen and is based on stories from Li An Phoa's river walk diary, the analysis of the Citizen Science measurements and the experience of joining as a co-walker for several days.
