Tallinn University of Technology

Recently, Bharat Maharjan defended his doctoral thesis ‟Stormwater Quantity and Quality of Large Urban Catchment in Tallinn”.

As far as environmental protection is concerned, little attention has been paid to stormwater so far, since it is considered to be clean water, which is thus non-hazardous to nature and waterbodies. Today, however, the viewpoints have changed and more attention is paid on stormwater as a potential source of pollution (by putting an emphasis on the flow rate as well as on the potential pollution risk).

One of the supervisors of the defended doctoral thesis, Head of the Water and Environmental Engineering Research Group at the School of Engineering Professor Karin Pachel said, "The objective of the research carried out in the framework of the thesis was to study stormwater runoff and quality through statistical evaluation of the monitoring data and to analyse and draw conclusions on short-term (up to 10 years) and long-term trends (18-19 years)."

The research results about the quality and quantity of Tallinn stormwater showed that the measured concentrations of most of the pollution parameters are, as in general, below the permitted limit values and decreasing trends are detected. The downward trends can first be associated with improved maintenance of the streets, renovation of the sewarage network and decrease in production in suburban agricultural regions.

"The experimental studies carried out enabled modelling of stormwater runoff quality based on the Mustoja catchment basin in Tallinn. The study outcome will be helpful for state authorities, water managers and water companies to use them in improving stormwater management strategies, planning and designing optimal monitoring and effective data collection systems, allowing them to select the most suitable stormwater drainage solutions and, if necessary, treatment measures," Professor Pachel explains.

The results of the defended doctoral thesis confirm that the state of stormwater has improved over the last decade considering the limit values. The data obtained in the study help to obtain more reliable and coherent information about stormwater quality and quantity, which in turn enhances sustainable planning, designing and stormwater policy formulation at national level.

The supervisors of the doctoral thesis were Professor Enn Loigu and Professor Karin Pachel (TTÜ).
The opponents were Peeter Ennet (Estonian Environmental Agency) and professor Pekka E. Pietilä (Tampere University of Technology, Finland).

The doctoral thesis has been published in the digital collection of the library: https://digi.lib.ttu.ee/i/?7131

Kersti Vähi, TTÜ Research Administration Office