DOI: 10.5593/SGEM2014/B31/S12.083


A. M. Pintilie,M. Paiu, I. G. Breaban, G. Romanescu
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-13-1 / ISSN 1314-2704, June 19-25, 2014, Book 3, Vol. 1, 639-646 pp

Cuejdi River drains a surface of 97.41 km2 in the south-eastern area of the Stanisoarei Mountains (Eastern Carpathians). The length of the main water course is 29.11 km, having its spring at the altitude of 970 m being a left tributary of the Bistrita River with the output in the Piatra Neamt City center. In the superior basin in the summer of 1991, following extensive landslides which blocked the Cuejdi River valley, the largest natural dam lake in Romania was formed, Cuejdel Lake. These water resources are well known for their excellent quality but lately due to increasing anthropic pressure, the quality decreased significantly. This paper seeks to prove the human interference in the state of the Cuejdi hydrographic basin using the Water Quality Index (WQI). Water quality status assessment can be defined as the evaluation of physical, chemical, biological state of the water in relation with the natural state, anthropogenic effects and future uses. WQI provides a single value expressing the average quality of water at a time, based on analytical values of physic - chemical parameters. In computing the WQI were used five physic - chemical parameters: pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5), nitrate (NO3) and phosphate (PO4). WQI is a 100 point scale that summarizes results from different measurements that can be divided into several ranges corresponding to quality classes, 100 being the highest score. The measurements include - 30 sampling points from the middle and inferior sectors of the river and 12 from the superior basin - Cuejdel Lake. Using WQI allowed the comparison of the two aquatic environments, differences in their quality being noticed. In the Cuejdel lake catchment as there are little anthropic influences and impacted mostly by natural environmental variables, the water quality is good with an average index of 86. Based on the WQI values the results revealed a classification of the river in three main quality sectors. The first one is the sector between the confluence of Cuejdi with Tiganca creek with a an index of 75 followed by the sector between Cuejdi and Gârcina villages, with a lower WQI of 66.5 as the river is influenced by both natural and anthropic variables. The last one Piatra Neamt - Garcina river sector is intensively affected by human activities (river crosses the city) having a lower quality with an average index of 58. This distribution of WQI along the Cuejdi hydrographic system basin proves that there is a decrease in quality due to the environmental impacts of human activities. The use of this index as a communication tool can be extremely useful for all authorities involved in water management resources.

Keywords: Water Quality Index, Cuejdi hydrographic basin, Cuejdel Lake, anthropic influence.