The effects of different land use and hydrological types on water chemistry of young glacial ponds

Abstract

The study aims to examine the effect of ponds on changes in water quality in a young glacial river catchment. The goal was to identify situations where a periodic hydrographic network is formed in outflow-free areas, which is connected with a higher order receiving area, as well as to study the circulation of matter in this type of system. This study answers the following key question: Do ponds affected by areal pollution substantially affect water quality in streams in periods where they become joined with the hydrographic network? The purpose of the research was to identify patterns associated with the functioning of ponds in young glacial areas in northern Poland on the example of the Borucinka catchment. Ponds were selected in order to generate a study sample characterized by different types of land use, local hydrology, and pond surface area. The study focused on the effects of catchment land use on pond water quality and the effects of periodic changes in local hydrology (linkage of surface flows with bodies of water) on pond water quality. Research has shown that land use in a pond catchment yields a substantial effect on pond water quality. The basic reason for the higher concentration of selected ions is close proximity to farms that generate wastewater, which reaches bodies of water in the study area. Seasonal changes in the concentration of biogenic substances were not observed in ponds. Only notable changes in the concentration of total nitrogen were observed due the episodic formation of a hydrographic network consisting of a collection of linked depressions. One of the more surprising findings was that permanently isolated ponds, which theoretically collect catchment pollutants all the time, are characterized by good hydrochemical conditions.