Assessment of Lake Sapanca in Turkiye shows why monitoring waterbodies is key to conservation

Monitoring the altering characteristics of lakes due to changes in the surrounding environment is a key to sustain lake ecosystems. It is also a missing component in rejuvenation efforts, according to Arup Kumar Sarma, professor, Indian Institute of Technology, Guwahati.

A case in point is Lake Sapanca, a critical freshwater source in northwestern Turkiye that faced significant environmental pressures due to urbanisation and industrial expansion, leading to habitat degradation along its shore. 

A study on the lake, published in the journal MDPI in January 2025, illustrated how land use changes are significantly degrading water quality, with rising levels of pollution from agricultural runoff and wastewater discharge.

The researchers from the department of information systems of the Middle East Technical University in Turkiye focused on non-point source pollution dynamics in relation to land use, land cover, hydrology, pollutant sources and water quality parameters. The findings emphasised the urgent need for conservation-driven water management strategies to mitigate environmental degradation. 

They monitored 12 sampling stations across the lake basin over three years from 2020-2023 and analysed key water quality parameters like total nitrogen and total phosphorus. The results showed that highly urbanised and agricultural sub-basins had the highest nutrient loads, leading to eutrophication — a process that depletes oxygen levels and harms aquatic life.

The scientists found that land use change had a significant impact on lake water quality. Urbanisation and increased population density showed a strong correlation with elevated nutrient loads, according to the report. Total nitrogen and phosphorus, the primary indicators of water pollution, in the samples ranged from 0.28-5.22 mg / L and 0.04-0.60 mg / L respectively.

Streams within highly urbanised and agricultural sub-basins exhibited the highest nutrient concentrations, which was driven by surface runoff, wastewater discharge and agricultural leaching, the analysis showed. In contrast, forested regions demonstrated greater nutrient retention, contributing to improved water quality. 

The study also identified seasonal variations, with pollution levels peaking during low-flow summer months. This highlighted the critical need for integrating conservation efforts with land-use policies to ensure long-term water quality sustainability. 

A major challenge identified in the study was the lack of integrated land and water management frameworks to assess the impacts of potential land use changes, climate change and pollution control measures. 

“A poor scientific approach among those involved in lake revival hinders understanding of waterbodies," said Venkatesh Dutta, Babasaheb Bhimrao Ambedkar Central University. "Cosmetic beautification often damaged lakes."

Proper mapping using geospatial tools and inclusion in revenue records are essential, the expert underlined. "Technological interventions occur only after assessing threats and water spread during pre- and post-monsoon periods. Creating water channels to revive small tributaries and riverlets is crucial.”

The study also underscored the necessity of scientifically driven pollution control strategies that should be prioritised over cosmetic beautification initiatives to ensure sustainable and effective water resource management.

Turkiye had been declared water stressed by World Wildlife Fund in 2021 due to improper management of water in the climate risked world. On top of this, the country lost waterbodies due to rapid urbanisation. This is similar to what is happening in India and countries in Global South.

“To rejuvenate the lake, the first step is the planning stage. The planning process needs to be integrated with relevant information, which can be gathered using GIS tools," said Pratap Raval, professor, College of Engineering Pune Technological University.

"In urban areas, many impervious surfaces are created due to changes in land use, and the main challenge is the lack of information on these changes,” Raval added. 

Implementing scientific monitoring frameworks, sustainable land-use policies and forest conservation measures is crucial to establish a harmonised balance between urban development and ecological restoration.

Ensuring the long-term sustainability of lake ecosystems is not merely an environmental obligation but a critical public health imperative, demanding urgent and evidence-based action.