Inventory of Reservoirs of Key Significance for Water Management in Poland—Evaluation of Changes in Their Capacity

Łukasz Pieron,Michał Habel,Magdalena Matysik,Damian Absalon

doi:10.3390/en14237951

Abstract

Dam reservoirs constitute an important element of protection against floods and hydrological droughts, and they ensure the possibility of producing electricity. Loss of reservoirs’ storage capacity has a significant impact on the management of their water resources, including flood protection and counteracting the effects of drought and the possibility of producing electricity. The paper presents changes in the capacity of 47 reservoirs in Poland that have the status of key objects of protection against floods and hydrological drought. Based on the collected, unpublished data, the changes in capacity from the beginning of the reservoirs’ existence to 31 March 2021 were calculated, which allowed us to determine the total amount of lost capacity and the pace of the processes taking place. From the beginning of operation (average operation time 48 years), the capacity has decreased by about 5%, which means that almost 200 million m3 less water is stored. Detailed analyses of the lost capacity also allowed for an illustrative presentation of forecasts for further changes in the short and long term. The results obtained represent a unique contribution to future national strategies for the management of sediment and reservoirs’ flood reserve and reduction of drought. The presentation of this problem seems to be important also in the context of climate change.

Highlights

Accepted: 24 November 2021For centuries, water reservoirs have constituted infrastructure necessary to manage water resources
The primary function for most of them is flood protection, while retaining water resources necessary to counteract the effects of drought and for the needs of hydropower plants; The average service life of the reservoirs is 48 years
The oldest analyzed Łakareservoir was commissioned in 1907, and the youngest Świnna Poreba 109 years later, i.e., in 2016; Since their commissioning until now, the total capacity at the maximum damming level has decreased by 192.656 million m3, i.e., by 5.2% (27 reservoirs showed a reduction in retention capacity, seven an increase, and no changes were observed for 13)

Summary

Introduction

Accepted: 24 November 2021For centuries, water reservoirs have constituted infrastructure necessary to manage water resources. The volume of bed load retained in the reservoir limits its water storage functions, and its efficiency in terms of retention and energy provided by it. It is estimated that 1% of the world’s gross reservoir capacity is lost each year [2]. This generates an economic loss of USD 6 to 10 billion per year [3,4]. According to information provided by the International Commission on Large Dams [4], the annual mass of bed load carried by rivers (both dragged and suspended material) has been estimated at around 24–30 billion tones and it has been estimated that around 1400 million m3 of sediment accumulates each year in reservoirs operating for 30–40 years. According to information provided by the International Commission on Large Dams [4], the annual mass of bed load carried by rivers (both dragged and suspended material) has been estimated at around 24–30 billion tones and it has been estimated that around 1400 million m3 of sediment accumulates each year in reservoirs operating for 30–40 years. [4]

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