Abstract
<jats:p>This book presents the quantitative and qualitative characteristics of groundwater, springs, rivers, and lakes in the Podlaskie Voivodeship, in northeastern Poland.Currently, the river network within the voivodeship is over 8,120 km long, enriched by over 14,270 km of ditches and drainage canals. Of the 309 natural lakes, the most valuable are the charophyte lakes and 38 dystrophic lakes.542 artificial reservoirs have been constructed, the largest of which, the Siemianówka Reservoir, has a maximum flood area of 32 km².It presents long-term changes in the voivodeship's water management resulting from economic development, shifts in public environmental awareness, and ongoing climate change.It describes the current natural state of aquatic organisms, the species diversity and diversity of macrophytes, benthos, and fish, using methods recommended by the EU Water Framework Directive, against the backdrop of the hydrochemical conditions of rivers and lakes.The high proportion of peat bogs and other marshy soils is the main reason for the fertility of river waters, while imperfect parameterization of the ecological status of waters underestimates the actual assessment of their natural values.The book highlights the major threats to aquatic ecosystems, including the drainage of nearly one-third of agricultural land, ongoing changes in sewage treatment systems, and the increasing share of urbanized areas.The book's appendices include lists of all rivers, lakes, and identified aquatic organism taxa.</jats:p>