This paper deals with the issue of documenting hydrological drought with the help of drought marks (DMs) which have been preserved on dozens of hunger stones (HSs) in the river channel of the Elbe in Bohemia and Saxony. So far, the hunger stones have been regarded rather as an illustration of dry seasons. Our aim was, among other issues, to draw attention to the much greater value of hunger stones and individual dry year marks inscribed on them. Therefore, we wanted to verify their reliability and better understand the motivation of their authors. For this purpose, we used the current extreme drought period of 2014–2019, which allowed detailed documentation of a hunger stone in Děčín, Czech Republic, with marks dating from 1536 to 2003. Thanks to the helpful position of the stones relative to the water gauge, we could compare the measured mark heights to the corresponding water levels. Simultaneously, we have scanned the objects into 3D format so that it is possible to perform a detailed inspection of all the marks, even those that were overlooked during the field survey. A review of scientific and technical literature from the 19th century showed that the marks of low water levels on stones and rock outcrops were to some extent interconnected with other important points. They were linked to zero points of water gauges, initially set up for navigation purposes, and to flood marks. The particular situation in Děčín is therefore a unique example of the epigraphic indication of low and high water levels in the enclosing profile of the upper part of the Elbe River basin. To verify the low water level marks or drought marks, we used the then current scientific studies focussing on dry periods. However, we also used the oldest series of daily water levels measured in Magdeburg, Dresden and Prague, available from 1851, i.e. the beginning of measurements in Děčín. These series had to be reconstructed or digitised from Czech Hydrometeorological Institute (CHMI) archive sources. Since 1851 we have been able to accurately identify the heights and sometimes even the specific days when the minima were marked.
After a thorough field examination and newly measured data, coupled with data obtained from a review of older literature presenting the first surveys of marks on hunger stones as presented in 1842, older marks of low water levels can be considered a reliable indication of the annual water level minima. The aim of the mark creators was not to make commemorative inscriptions of drought but to register the exact minimum water level. Deviations between the marks and the water gauge records did not exceed 4 cm, and only exceptionally was the disparity greater.
From the material obtained so far, an overall slightly decreasing trend of water level minima since the end of the 18th century is noticeable. The view on minima of the 16th and 17th centuries is based on only a few items of data, and it is difficult to generalise. However, the minima obtained are comparable to or lower than the data from the critical dry periods of 1842 and 1858 to 1874. Our verification of low water level marks should be an incentive to process all available epigraphic documents of this kind in the near future in closer cooperation with colleagues from Saxony. The potential of these objects offers a deeper knowledge of periods of hydrological drought and possibly of morphological changes in the Elbe riverbed.
In recent years, the phenomenon of drought has become the most prominent manifestation of climate change in central Europe. However, objective evaluation and assessment of its extremities is challenging due to difficulties in describing the phenomenon of drought and the varying impacts of it. Drought, along with floods, ranks among the most commonly evaluated hydrological extremes. While a flood is caused by short-term excess of water that causes damage, hydrological drought follows a long-term deepening of water scarcity.
Our contribution is focused on hydrological drought and more precisely on the minima of low levels. Low water levels and flow rates after long periods of precipitation deficit represent particularly valuable information about catchment hydrology.
Therefore, the baseflow, the groundwater accumulation, long-term depletion and hydrological drought propagation are also reported (van Loon, 2015). The minimum water level or flow is, to a large extent, summary information on the status of a given river basin.
Like floods, hydrological drought is difficult to study without an examination of historical events. However, what options do we have regarding low water levels? The available hydrological series usually cover no more than 150 years. The longest hydrological series of measurements in Cairo, 622–1933 CE, representing 1311 years of Nile observations (Shahin, 1985), was used to assess drought and its interrelations with phenomena such as El Niño. In Europe, the longest continuous series comprising measurements of water levels in Magdeburg, Germany, started in 1727 (see the following text), and the measurements in Paris started in 1731 (Delametherie, 1800). However, it is impossible to conceal another complication, namely that systematic hydrometric measurements have, for the most part, only been available since the end of the 19th century. Stable profiles where we can assume the validity of the rating curve as far back as possible are very valuable. Systematic series of water stages are, therefore, testimony to runoff fluctuations but partly also to changes in the stream cross section and the catchment, both natural and anthropogenic.
Studies that focus on the identification of past dry periods and possibly on the wider context within the North Atlantic Oscillation (NAO), El Niño–Southern Oscillations (ENSOs) are based mostly on an analysis of precipitation deficit or indicators that include temperature and hence loss by evaporation (e.g. Mikšovský et al., 2019). They are necessarily based on previous reconstructions of temperatures and precipitation based on an analysis of documentary sources. However, if we want to describe how the rainfall deficits and other weather influences were reflected in the runoff from the surveyed river basin, the options we have so far are rather limited.
Based on the available series of daily flow rates in Děčín, Czech Republic (1851–2015), Brázdil et al. (2015) referred to a period of low flows between 1858 and 1875.
With the help of deficit volume analysis with a fixed annual (
The authors elaborated on in detail the selected dry years of 1808, 1809, 1811,
1826, 1834, 1842, 1863, 1868, 1904, 1911, 1921, 1934, 1947, 1953, 1959 and
2003, i.e. eight cases in each century representing a total of 16 cases selected
on the basis of the lowest
What credible documents of low water levels existed before 1851 (the start of record-keeping in Děčín), 1825 (the start of record-keeping in Prague) or 1727 (the start of record-keeping in Magdeburg)?
Based on reconstructed data on temperatures and precipitation between 1766 and 2015, Hanel et al. (2018) indicated extreme deficits in precipitation, runoff and the water content of the soil surface layer, identifying the droughts of 1858–1859, 1921–1922 and 1953–1954 as extreme.
However, there is no doubt, similar to flood analysis, that verifying the model results according to the actual water level and flow rate increases their credibility considerably. We have a relatively large range of palaeostage indicators to describe the maximum water levels during a flood. These palaeoflood indicators comprise various types of sedimentary (e.g. slack water flood deposits) and botanical evidence such as impact marks and damage on trees (Benito et al., 2004, 2015; Wilhelm et al., 2019; Schulte et al., 2019).
Low water levels and flow rates for pre-instrumental hydrology are seldom addressed but with some exceptions. For instance, Shamir et al. (2013) presented methodology to identify field-based geomorphologic marks of low flows in ephemeral arid streams that can be indicative of minor flash floods. Unfortunately, the motivation is different, and the potential for indicating historical low flows in humid climates has low utilisation.
Therefore, low water level indicators available through documentary sources are unique data records (Brázdil et al., 2018) for recording past hydrological droughts, with the precision given by physical imprints provided by epigraphic marks.
During drought, attention was paid to objects normally hidden below the water level. Most often these were large boulders, protruding rocks and sometimes even point bars or slip-off slope sandy deposits with specific local names. In many cases these were also artificial objects: protruding foundations of old bridges and building elements. Around the Rhine these were the remains of old buildings, old bridges etc. (Wittmann, 1859). Sometimes there was an interesting local tradition; in the sandstone area on the Czech/Saxon border, it was the creation of commemorative inscriptions, particularly inscribing the current year with the low water level. Today, these objects are mostly called hunger stones (hereinafter HSs).
This article focuses on these hunger stones; it seeks to clarify their purpose, origin and meaning. Traditionally, water management experts and historians and perhaps ethnographers in Bohemia considered inscriptions and the year as indicated on hunger stones to be an interesting phenomenon symbolising drought.
At the same time, however, the understanding prevailed that the marks of dry years were merely commemorative records with no deeper meaning and that they were more or less randomly positioned. We believe that it is in this area that we have taken a substantial step forward in the explanation and possible use of these records.
We have therefore focussed on the city of Děčín, located in the
lower section of the Czech part of the Elbe River basin. The best-known
hunger stone is located here, and all the important height surveying of all the
epigraphic marks was undertaken in the summer of 2015. In 2018 the whole
stone was scanned. This article discusses to what extent the inscription
years have the character of historical minimum water levels. The objective is to document and explain the phenomenon of hunger stones in more detail. We aim to answer the following questions:
Are the year marks only commemorative for that dry year and when do they
represent exact records of annual minimum water levels? Are there consistent relations in the heights of stage minima among
different stones? What is the relation to the systematic series of measurements? Do the elevations suggest any trend in water levels?
The Elbe River valley between Litoměřice and Pirna was made famous in a number of prints and paintings by 19th century Romantic painters such as Adrian Zingg (1734–1816) and Caspar David Friedrich (1774–1840). Zingg was Swiss but lived in Dresden; he probably coined the name of the Saxon Switzerland region, which later extended to Czech–Saxon Switzerland (Frölich-Schauseil, 2018). The Elbe, which leaves the territory of the Czech Republic in a deep rocky canyon and ends its upper stretch here, flows between Lovosice and Děčín through the Krušné Ore Mountain system. Along its path it first intersects the volcanic zone of the České středohoří area. Below Děčín, it then flows through a landscape of sandstone formations. The Elbe riverbed is situated at an altitude of about 120 m above sea level in a deep sandstone valley 200–300 m below the level of the sandstone plateau (350–450 m a.s.l.). Protruding volcanic formations reach a height of 500–800 m a.s.l. The Děčín and Hřensko cross sections represent the closing profiles of the Czech part of the Elbe. In addition to wood, local sandstone was a traditional building and sculpting material here and throughout the North Bohemia region. However, it was also used for rich epigraphic production on the spot – on rocks and boulders (Jenč et al., 2008). It is quite logical that water levels were recorded adjacent to the river where possible, both minima and maxima.
The city of Děčín in 1842 with indications of the original extinct town (13th–14th century), area of shallows (lightest blue), water gauges RG1, RG2, G1851 and OG, and three hunger stones (HS1, HS2, HS3).
At the centre of our study is the city of Děčín (Fig. 1), known among other things for its unique series of flood marks (Brázdil et al., 2005; Elleder, 2016a) and hunger stones. The earlier documentation, which comes from commission inspections of the Elbe riverbed, revealed previously unknown facts. In 1842, there were still a total of three hunger stones in the city of Děčín with engraved years: two on the left bank (HS1, HS3) and one on the right bank upstream of the ferry crossing (HS2) (Protokoll, 1842). The preserved stone (HS3), which is located in the lower part of the deeper riverbed, is the centre of our attention.
This place was probably advantageous long ago as a settlement with a ford at
the river confluence and below the protruding sandstone ridge. At the end of
the 13th century a royal town was founded here (Fig. 1;
Velímský, 1991). Possibly in connection with a rich flood period between 1342 and 1374 (Elleder, 2015), it was abandoned and
transferred to the other side of the rock ridge, where a castle stood and
the manor house is situated nowadays. There were at least two places in
Děčín that were problematic from a navigational point of view.
The first hunger stone (HS1) was located near the first shallow water area.
It is related to the confluence of the Elbe River with the Ploučnice
River entering from the right, the Jílovský potok stream from the
left and the sediment deposits. On the rock below the castle there are flood
marks from 1432 carved into the rock block. Alongside, a water gauge (RG2) is
located indicating the Prague ell units of length (1 ell
The first partial goal was to prove that the water level marks on the hunger stone in Děčín and other stones were meant by their creators as signs of annual minima in the years attached to the water level marks. The simplest means are a comparison with concurrent water level measurements on a nearby water gauge (accurate identification) and the use of other available measurements (approximate confirmation of significant water level decline). We used primarily four series stored at the CHMI (Czech Hydrometeorological Institute). These are the systematic series at the sites of Magdeburg (1727–1880), Dresden (1801–1829), Prague (1825–1890) and Děčín (1851–2019).
Prof. Harlacher, the first head of the Czech Hydrological Service in Prague (Elleder, 2012), needed a long water level series for studying past drought periods. In 1875–1880 he obtained the oldest series from the Water Management Directorate in Magdeburg. This record was found 110 years later in the 1990s in the unclassified records of the Czech Hydrological Service. A copy was sent to the International Commission for the Protection of the Elbe River (IKSE) Magdeburg headquarters. Digitisation was carried out in 2005–2007 in cooperation with the CHMI and the T. G. Masaryk Water Research Institute (T.G.M WRI). The value of these measurements is considerable as the series covers the whole period of 64 years in the 18th century continuously, and there is no other alternative for central Europe. Its disadvantage is the downward trend in annual minima, which can be explained largely by the shortening, deepening and changing the profile of the Elbe River around 1816 (Simon, 2010). However, in our case we can identify very well particular annual water level minima and their associations with the years on hunger stones between 1746 and 1800 (hereinafter DM for drought marks or for minimum water level signs). By identifying the annual minimum water level in Magdeburg, we could estimate the likely date of creation of the DM in Děčín, considering the Děčín–Magdeburg water transit time (6 d).
A copy of this series, probably made by an official of Prague City Hall in 1829, offers evidence that the systematic series does not begin in 1806 (Fügner and Schirpke, 1984; Fügner, 1990) but at least in 1801. The series was found in the 1990s by a private researcher, Jiří Svoboda, in the Prague City Archives, and he left it to the CHMI. Dresden has a clear advantage over Magdeburg in its geographical proximity to Děčín, so we preferred it for the 1801–1829 period.
In Prague, an occasional water gauge (possibly flood gauge) was probably
established by Antonín Strnad, the director of the Clementinum observatory, in the
profile of the Monastery of the Knights of the Cross in 1782 (Brázdil et
al., 2005; Elleder, 2016a). Later (about 1821) it was transferred to the
profile of the Old Town Mills, Prague. Systematic observation of the water gauge
started in 1825 (for more detail, see Elleder, 2016a). The profile of the
Old Town Mills was related to the weir normal (i.e. to the weir crest), so it
was a profile that did not change. According to Novotný (1963), the
original observation diaries and perhaps even annual reports of the
measurements were lost. Only the published values of the monthly minima,
maxima and averages in the yearbooks of the Clementinum observatory
remained. As with other observations (e.g. in Magdeburg and Vienna),
the Prague observations were published weekly and later daily, in daily
newspapers. Therefore, we decided to regain the daily measurements of water
levels published in the daily
As with other profiles along the Czech section of the Elbe River, a
systematic observation of water levels was introduced in Děčín.
At first there was an old water gauge (OG) (Fig. 1), which was located in
the profile of the site of the steamship navigation directorate probably
before 1842. Later, but probably no earlier than 1858, the new water gauge
(G1851) started to be used on the pillar of the Empress Elizabeth Bridge
(built in 1851). The problem is a newfound uncertainty in the change of the
zero point of the water gauge (Protokoll, 1858), the height of which might
have been elevated by 16
The oldest measurements of very low flow rates in Děčín and on the Saxon side.
This study was preceded by about 10 years of waiting (since 2005) for a suitable opportunity to undertake a field survey of hunger stones that are totally or partially below the surface at normal summer flow rates. There was no other possibility than to try to find an alternative solution. In 2009, as part of a preliminary study, we tried to use rich iconographic material from the period of 1894–1994 and reports of the hunger stone in Děčín in contemporary newspapers. In the older press materials, reports were looked up that showed when the hunger stone was visible and an indication was given as well as to which year marks were above the relevant water level. Then it was easy to classify the marks into height groups with a water level higher than that of the day reported. Further specification of heights was possible only on the basis of photographs by comparing which mark was higher or lower in the given group. The marks were connected by contour lines indicating the resulting bands. The estimated water levels were then compared with the annual minimum values. The result pointed to the expected possible concordance with the annual water level minima. We have followed a somewhat similar approach with the hunger stone in Pirna.
In 2011, it was possible to carry out field verification of the estimated heights of the marks that were located on the highest part of the stone. In 2014, this opportunity was not used as we believed that the dry season would have a longer-term character, which was confirmed in 2015 and 2018. In 2015, the hunger stone in Děčín (HS3) and the stone in Těchlovice were surveyed. During the surveying of the stone in Těchlovice, located on the slip-off slope of gravel deposits, it was not necessary to make any ground adjustments. However, only relative heights recalculated to the minimum height of 1842 were measured.
The surveying of the Děčín stone in 2015 required preparation, including sediment removal and stone cleaning (manual work of two to three people for 3 h or more). In 2015, the sediment layer reached the mark of 1616, i.e. around 70 cm in height. In addition, it was necessary to make a pit around the stone's very low marks. Using a pump with a syringe to wash away sediment, blasting stone and pumping water from the sump significantly accelerated the work.
The measured mark heights were linked to the fixed geodetic point nearby. All surveyed geodetic levelling points were photographed. The measurement took place on 14 August when water levels dropped to their lowest just before the expected rainfall episode which increased the Elbe water level significantly. The participants in the measurements were Ladislav Kašpárek and Jan Kašpárek from T.G.M. WRI, Libor Elleder from the CHMI, and a land surveyor, Zvonimír Dragoun (presented at EGU 2016; Elleder, 2016b).
We did essentially the same when scanning and creating a 3D model in 2018.
The stone was prepared by colleagues from the CHMI (Martin Groušl,
František Pěkný and Martin Hubený) in advance on 27 July. The
final adjustment was made on the day of the measurement and was assisted by
Daniel Kurka, Libor Elleder and Martin Hubený. Martin Hubený also performed
a hydrometric measurement in the hunger stone profile (HS3; Fig. 1),
including the cross-section measurement using the ADCP (acoustic Doppler
current profiler). Three-dimensional scanning was performed by Libor Tělupil from the
VR3D Company (
In 2015, 33 points were surveyed, mostly engraved lines with attached year indications. For obvious reasons, making a DM is much more difficult than making a flood mark. It is difficult to estimate when the water level starts to rise (see discussion). Therefore, it was not always certain whether the sign would represent an indication of the immediate low water stage (LL), the local minimum (LM) or the annual minimum (AM). For verification and approximate determination of the minima marked on hunger stones prior to 1727, only documentary sources are available: i.e. reports on weather and impacts of hydrological drought, such as the drying of smaller streams and wells, the shutdown of small and medium mills, or the necessity to travel dozens of kilometres to a grain mill. We reproduce this information primarily from Brázdil et al. (2015). The decade frequencies of drought occurrence since 1500 (Brázdil et al., 2013) were a valuable basis for verifying the position of marks, especially for the 16th and 17th centuries.
For the evaluation of the DMs made after 1727, we used the above-mentioned series of measurements in the Magdeburg series rather for dating verification and the Prague and Dresden series for assuming a very approximate estimate of the significance of the minimum. Concerning newer cases after 1851, it is possible to confirm the correct or incorrect position of the mark (DM). Regarding deviations from the measured water level for that day, we consider the precisely marked height (PMH) at a deviation of 0–4 cm and approximately marked height (AMH) at a deviation of 4–8 cm. We consider larger deviations as a possible mistake when placing the measuring rod or a poor understanding of a difficult-to-read position of the mark or line. If the DM does not have accurate dating, we can assume dating according to the minimum water level when there is an exact PMH identification with the minimum water level.
One very important product is the digital model of a hunger stone, which can
be viewed and edited in contrasts by selecting the “Shaders” option in the MeshLab
processing system (
Some DMs are missing on the Děčín stone, but we find them elsewhere. If their heights were measured during commission inspections of the Elbe River in 1842 (Protokoll, 1842) and 1850 (Protokoll, 1850), relative to the level of 1842, these differences can be utilised. Thus, some heights (1766, 1782) from the lost stone in Děčín (HS1), Dolní Žleb (1516, 1615, 1636, 1706, 1834 and 1835) and Pirna (1706, 1834 and 1835) were added. For other hunger stones, we can only take into account the positions of the marks, reviewing whether they are in accordance with or contrary to the facts found.
It is very likely that the most objective records of hydrological drought or, more specifically, records of low water levels are related to navigation in central Europe (Brázdil et al., 2019b, mentioned a limiting of water transport in the years 1686 and 1746). It cannot be ruled out, for example, that the mapping of the Vltava River (by David Altmann of Eidenburg) and the river regulation by Kryšpín Fuk (1640–1643), abbot of the Premonstratensian monastery in Strahov (Wiesenfeld, 1844), were made possible merely by a drier period, probably culminating in 1642 (documented by Pekař, 1998). Also, surveys of the upper Vltava River reaches, carried out by Lothar Vogelmonte for the intended canal between the Danube and the Vltava rivers in the years 1700–1715, show a possible time relationship (Wiesenfeld, 1844). The dry years of 1705, 1706 and 1707 (marked on hunger stones) could present an opportunity to explore the streams in times of low water levels. The drought in 1726–1728 clearly affected the beginning of water level measurement in Magdeburg (Hofmann, 1850) in 1727. It was probably connected with the frequently quoted commission of Jan Ferdinand Schor, which carried out a survey of the Vltava River with regard to navigation and the construction of the first lock chambers (Wiesenfeld, 1844). The agreement on duty-free navigation on the Elbe (see Faulhaber, 2000, 2013) in 1821 (the year was also marked on the stone in Děčín, HS3) along the Elbe River up to Hamburg led to increased interest in monitoring water levels for individual participating states, including the Austrian Empire and Saxony up to Denmark.
The catastrophic dry period of 1834–1836, affecting both the Elbe and the Rhine basins, raised the issue of a general downward trend in water levels, especially in the Elbe basin. H. Berghaus pointed out this trend and the poor prospects of Elbe navigation (Berghaus, 1836, 1854). A forestry expert, Reuter of Aschaffenburg (Reuter, 1840), pointed out the possibility of this trend being linked to the deforestation of the central European landscape.
In this context, there is a link with the disastrously dry year of 1842
(Brázdil et al., 2019a, indicated that in 1842 summer precipitation was
significantly reduced from western to central Europe), and a commission of
the Elbe states (Austria, Saxony, Prussia, Anhalt, Hamburg and Denmark) was
organised to improve navigation conditions. The aim was a thorough
description of all fixed points (water stage gauges, flood marks and marks
on hunger stones), navigation conditions and minimum navigation depths along
the navigable section of the Elbe from the town of Mělník (Bohemia)
to Cuxhaven (Saxony). Stones and rocks in the river were of dual importance
for navigation. They were a dangerous element, but at the same time they
served as orientation for navigation. The commissioners travelled by boat,
and the Mělník–Meissen section was surveyed from 5 to 11 September 1842, 14 d after reaching an absolute minimum water level. The water
levels of the Vltava and Elbe were still very low, but they were already 9
to 20 cm higher than the minimum of the previous August. In the city of
Děčín, measurements were made from 7 to 8 September (Protokoll,
1842) at a water level of about
The commission compared the situation with the last commission survey in
1842 and registered the removal of some barriers to navigation. Gauging some
low water levels through their relation to fixed points is of the utmost
importance to the subject of this study. These fixed points were only flood
marks (in Roudnice, Ústí nad Labem, Děčín), and
alternatively the current water levels in 1850, or zero point of a water
gauge, were used (old water gauge in Litoměřice, Ústí nad
Labem, railway water gauge in Dolní Žleb, water gauge in Pirna). Until now, only two of the original three hunger
stones remained in Děčín. The Austrian commissioner carried out
a precise survey of all the flood marks on the castle rock in
Děčín (Krolmus, 1845; Brázdil et al., 2005) and related
their heights to the minimum of 1842. The commission was active in September
when there was a significantly higher water level than in 1842. Therefore,
the marks on the hunger stones were underwater and thus were difficult to
recognise. For the present stone (HS3), its top at
The year 1857 was very dry, just as 1858 proved to be. The commission was in
Děčín on 20 May 1858. The water level was in the range of
Considering the record low water levels of the Rhine, Josef Wittmann, director of the Society for the Study of the History and Monuments of the Rhineland, published a comprehensive publication (Wittmann, 1859), which is also an inventory of periods with low water levels of the Rhine from 70 CE (Tacitus' description of the very low water level of the Rhine) to 1858 and an overview of prominent objects hidden underwater during a normal water stage of the Rhine. According to his work, the level of the Rhine dropped to a record low in 1858, lower than in 1788, 1813, 1818, 1822 and 1830, at least according to the water gauge in Cologne. It was this alarming water level that was simultaneously the main motivation and the opportunity for his work. The year 1858 was recently indicated by Hanel et al. (2018) as one of the most extensive drought periods. The years 1857 and 1858 in the Elbe basin are also the beginning of 2 decades of the occurrence of significant and catastrophic periods of low water levels. These periods are represented by the years 1858, 1863, 1864, 1865, 1868, 1873 and 1874 (Elleder et al., 2020), most of which can be found on various hunger stones in the Elbe. At that time Professor Bruhus of Leipzig (Bruhus, 1865) was studying hydrological drought in Saxony. His work was the basis of a study by the forest counsellor von Berg (von Berg, 1867), which again presents the same idea of the loss of water throughout central Europe and documents it with the help of precipitation balances and minimum water levels not only in the Elbe, Oder and Rhine but also the Elster and Mulda rivers. The author saw the cause again in the intensive use of the landscape, especially deforestation. The prominent Austrian water manager G. von Wex (Wex, 1873) applied the recorded minima of water levels from 1616 to 1842 when demonstrating a steady downward trend in 1842–1873. He also recalled the earlier views of Heinrich Berghaus and the Prussian Counsellor Hagen. However, Hagen refuted the downward trend for the Rhine, for example. On the other hand, Heinrich Grebenau, a noted expert in hydrometry who also participated in the famous international survey of the Rhine in 1867, supported the idea of flow decline with his flow measurements.
This drought also had a specific impact on Bohemia, the most industrial part of the Austrian monarchy. In 1869, another Elbe navigation commission (Wex, 1873) was held. In 1871, Andreas Rudolf Harlacher, a professor at the Prague Technical University, established a temporary station for hydrometric observations and for calculating the amount of runoff from the Czech Elbe (1871–1872) (Harlacher, 1871, 1872). According to Cvrk (1994), the year 1873 brought the intensification of river regulation of the lower Elbe (mostly digging and removing boulders) and finally the deepening of the riverbed by approximately 20–30 cm. The catastrophic drought in 1874 led, after a broad discussion, to the establishment of the Hydrographic Commission of the Kingdom of Bohemia based in Prague (Elleder, 2012). The floods and the generally wetter period of 1880–1882 ended the long occurrence of drought during the period of 1858–1878. Extensive hydrometric measurements, including a detailed mapping of the riverbed, were made by Harlacher in Děčín between the old road bridge and the railway bridge in the 1880s (Harlacher, 1883). Harlacher was interested, as Berghaus earlier and von Wex at the same time, in the downward trend of the Elbe water levels. Therefore, he collected the above-mentioned series of measurements (Dresden series 1806–1872, not found at the CHMI, and Magdeburg series 1727–1880).
After the period from 1880 to 1891, the low water levels in 1892 and 1894 intensified the pressure to regulate the Elbe. In 1896, a canalisation commission was established for the regulation and canalisation of the Elbe between Mělník and Ústí nad Labem. The aim was to build a navigation link up to Prague and ensure a navigation depth of 180 cm (an increase of 50 cm) in the period of 1896–1938 (Cvrk, 1994). This is a very important fact for our work, as it resulted in a substantial shift of about 50 cm in the flow rating curve in the Děčín profile in the area of low flow rates.
The next stage was to put into operation the Vltava cascade, the
construction of the Slapy waterworks in 1957
(
Drawing documenting the position of the hunger stone known as Ara Bakchi, Altarstein and Elfenstein near Bacharach, perhaps in the dry season of 1636, 1639 or 1642 (Merian, 1645), the position of which is marked by a red triangle in a cut-out view of Bacharach.
Central Europe and the occurrence of objects similar to the hunger stone in Děčín.
Wittmann's work suggests that the oldest designation dates back to 1305 in
Olten on the Aare River and in Strasbourg in the same year or in 1302 or
1303. The most notable example is the so-called
Among similar objects there is, for example, the rock in Olten in the Aare
River. Around Bodensee (Lake Constance), such objects indicated low lake levels in Staad,
Mammern and Konstanz. In 1750, the remains of the assumed ancient buildings,
the pillars of the bridge in Cologne and the aforementioned
Along its upper reaches the Elbe is a much smaller river than the Rhine, for
example, in the narrow canyon area between Bingen and Koblenz (with an
average flow rate of approximately 2000 m
The term
The site is located above the sandstone canyon, and the valley is formed by
rocks of volcanic origin. On the left bank of the Elbe River, approximately
85 km downriver (below Mělník), the Elbekarte map (1848) shows the
Survey of DM heights in Těchlovice.
In 1842, three hunger stones were examined within the activities of the Elbe Commission (Protokoll, 1842) (Fig. 1).
According to the report, the first hunger stone (HS1) was located near the
left bank of the Elbe opposite the castle rock, i.e. also opposite the
well-known flood marks from 1432 to 2013 and the historical rock water gauge
(RG2) on the right bank (Brázdil et al., 2005) (Fig. 1). On the stone
(HS1), the approximate depths of DM minima in 1719 and 1766 were measured
in September 1842. The 1782, 1790, 1835 and 1842 marks were surveyed
precisely (Table 1). Elevation ratios were expressed as heights above the
previous August minimum of 1842. In 1850, the depth of the 1782 mark (HS1)
was determined as 7.5
The second hunger stone (HS2) was supposed to be upstream of the ferry
crossing on the right bank. There was a minimum mark from 1800 situated 4.5
The third stone (HS3) was located by the commission on the left bank, and it
still exists. This object is the centre of our focus. The commissioners
described the 1616, 1746 and 1790 marks, which were documented many times
later in 1892, 1904, 1911 etc., and they also mentioned the 1835 mark (not
found). Unfortunately, they only determined a difference of 5
The stone (see the methodology) was divided into four height ranges and the following sides: embankment side (ES), left side (LS), right side (RS), platform (P) and the highest part of the stone's ridge (R) (Table 3; Fig. 4)
Division of HS3 stone and list of marks by ranges.
The hunger stone was divided into four height ranges (Table 4) and the following sides
The platform P, the ridge part R and the side (ES) of the stone are about 360 cm wide, and the distance between the bank and the river is about 400 cm. The
oldest marks – 1536, 1616, 1746, 1790, 1800, 1811, 1842 and 1868 – were placed on the
side (ES) facing the river bank in the range of 111 to 150 cm. Only the mark
of 1707 was placed on the platform (P), where the markings from 1892 to 1904
continued. The minimum marks of 1904 and 1911 were simultaneously placed on
the right side of the stone (RS) (downstream). The lack of space also
apparently led to the rewriting of the inscriptions at the 1911 mark and a large
inscription: “
Using the example of the measurements in 1850, it is possible to clarify the
system of rock gauges – RG1, RG2 and OG – linked to hunger stones and the
newly measured heights of the flood of 1784 (measured in 2004) and the minimum of 1842
(measured in 2015). An administrator at the Děčín estate, who was also a
forester and contributor to the Patriotic Economic Society Seidel (Neue Schriften, 1845),
determined the height of the flood mark of 1784 on the rock gauge (RG1) as
Overview of the annual water level minima on the hunger stones in Děčín.
HS1, HS2, HS3 – hunger stones in Děčín; HD – historical documentation; B – mentioned by Brázdil et al. (2015); T – HS in Těchlovice; DZ – HS in Dolní Žleb;
In the river map (Elbekarte, 1848), a total of seven to eight stones are marked on
the right bank of the Elbe River upstream of Dolní Žleb, followed
by another six downstream, as indicated in the Protokoll (1842). At the former
customs house (left bank), the Elbe River flow was narrowed by two rock
outcrops: the Monk's Stone (
Marks on a hunger stone in Dolní Žleb surveyed in 1842 (Protokoll, 1842).
Hunger stones detected in Dolní Žleb by Randák (2015, 2017a).
? – the inscription is unclear.
None of the commissions (1842, 1850 and 1858) identified a stone with a year
indication. The survey carried out by experts of the Elbe River Board on 26 August 2017 (flow rate 75 m
Hunger stones detected in Hřensko by Randák (2015).
? – the inscription is unclear.
On the right side upstream of Schmilka, the commission (Protokoll, 1842)
found a large stone with an 1842 mark (4 September 1842), which was 4
A mark from 1868 remains there today.
The commission did not mention any remarkable stones there in 1842, 1850 or
1858. However, German sources mention the year 1681, and on another stone there
are marks from 1797, 1914, 1865, 1900, 1911 and 1914
(
None of the commissions (1842, 1850 and 1858) found any remarkable stones there. However, the Pillnitz site has been, next to Dresden and Meissen, a place of important flood level observations as early as 1736 (Pötzsch, 1784). There is a clear inscription from 1778, which is probably not the minimum water level (see discussion). The marked HS includes minima: 1893, 1904, 2003 and 2018.
This was located near a small gate at the navigation control point, but this
situation no longer exists. Nearby, there was a transverse dam opposite to
which a flat stone with engraved marks could be seen. According to the
Protokoll (1842), the marks of 1616, 1706, 1707, 1746, 1834 and 1835 were
registered and surveyed (the other marks were illegible). The water level at
that time was 6
Marks on a hunger stone in Pirna surveyed in 1842 (Protokoll, 1842).
None of the commissions (1842, 1850 and 1858) mentioned any remarkable stones. Nevertheless, pictures are published of hunger stones in the Kotta locality with an inscription of the year 1630 (it is possible that it rather concerns 1636). We have no views regarding the credibility or existence of these stones. In the Radebeul locality, there is probably a millstone with an inscription of the year 1911. In the Laubegast locality, there are stones with inscriptions of the years 1892, 1893, 2003 and 2013. In the Tolkewitz locality, there is a stone with a 2016 mark. In the Augustbrücke cross section, a low water level of 1705 was indicated (Pötzsch, 1874), and now there is also a mark from 2018.
We learned about the hunger stone from older literature of the 18th century. None of the commissions (1842, 1850 and 1858) found any remarkable stones. The only report on the flood marks is conveyed in literature. Ursinus (1790) mentions the dry year of 1746 (see Tables 4, 9, 10) and the discovery of various stones in the Elbe River. In Meissen year markings were found on one of these stones, indicating a dry year in 1654.
The Protokoll (1842) describes a hunger stone (a rock rising from the river)
on the right bank of the Elbe with minima from 1718, 1746, 1790, 1800, 1834
and 1835. The height of 1800 was
On 29 May 1858 the committee recorded the water level at
There are always fewer records of low water levels (if any) than marks of
high water stages, the only exception possibly being the sandstone Elbe
valley between Děčín and Pirna. It is more difficult to make a
mark of the minimum water level than to make a flood mark due to the
following reasons:
It is and it has always been difficult to estimate the correct instant of
reaching the minimum level. More demanding inscriptions were probably made
in advance. The designated place was probably enclosed by a small barrier
beforehand so that the mark could be completed at a time when it was clear
that the minimum had been reached; i.e. when the water was rising.
Therefore, the logical moment of making the minimum mark is after the
minimum has subsided (in reality, 1–15 d before the annual minimum level,
these DM levels were engraved; see Table 4). However, it is not clear
whether this was a local or annual minimum. In some years, the level fell even lower. The exact date is given, or a
range of water levels for a given year is made, such as in
Děčín for the years 1904, 1921, 1930, 1934 and 1957. It is also
surprising to note the range for the year 1707 in Pirna as otherwise the
low water mark might have been rather doubtful. The mark of 1842 in Pirna
seems to have a different meaning, being the actual water stage in feet. The minimum markings are often made upside down (made from the upper side of
the stone) while some were made while standing in the water or at a lower
position (orientated normally). Therefore, the engraved lines in such cases
are not below the date (in the graphic sense) but above it, thus closer to
the water surface (in Děčín, for instance, these DMs: 1536,
1707, 1892, 1893, 1904, 1911 and 1934). The marks are completed by monograms (see Pažourek, 1995). The second oldest
mark, from 1616, was completed by the initials F. L., from 1707 by the
initials M. L. R., and from 1746 by the initials H. M. L., so there is a
possibility that they concern members of one family. Later, in 1790, there
are the initials H. G. T., in 1800 A. I., in 1811 and 1842 W. E., and the
designation is missing for 1821. Another change is the first year
corresponding to the instrumental series, so in 1868 the initials are F. H.;
however, in 1892 and relisted in 1893, the designation contains the initials
U. E. The originator of other marks was probably the popular Franz Mayer,
who is the author of the 1904, 1911, 1921 and perhaps even the 1930
markings. In connection with the 1904 mark, the popular inscription “ There are overlapping inscriptions. In view of the place of origin and
various perhaps personal, local, national and even commercial
considerations, there were exceptional cases of overlapping inscriptions.
Thus the 1904 mark, perhaps made by a certain Rotsch, was obscured by the
second inscription, “
Verification of marks of 1500–1800 according to the decade frequency of drought reports by Brázdil et al. (2013).
There are no direct water level observations for comparison purposes in the
1516–1727 period. According to Brázdil et al. (2013, 2015), the
1511–1520, 1531–1540 and 1631–1640 periods had a higher decade frequency (
From 1636 to 1707, i.e. for 70 years, there are no marks of minimum water levels. Brázdil et al. (2013) pointed out that the three decades of 1641–1650, 1661–1670 and 1671–1680 had a minimum decade occurrence of drought reports (two cases per decade). Moreover, it is a period of the Maunder Minimum (Eddy, 1976), i.e. the 1640–1720 period, probably the most intensive period of the Little Ice Age (LIA).
Verification of marks in the period of 1727–1800 according to the annual (MAW, grey line) and summer (MAS, red line) minima of the Magdeburg 1727–1800 series with annual minima identified (and derived) from the marks on the HS3 hunger stone in Děčín (MA, blue circles).
Since 1727, we have been able to identify the minima in the years highlighted in Fig. 6 with the help of the Magdeburg series. A very good time coincidence is apparent for 1746, 1766, 1782, 1790, 1800, 1811, 1835, 1842, 1858 and 1874. The year 1868 is missing, thus there is no representation of a deviating minimum in Magdeburg; however, there is a significant mark later in 1869. The year 1766 represents the only significant winter minimum which was marked on hunger stones. However, the winter minima of 1818, 1823 and 1862 are missing.
The water level DM minima are plotted on the water level scale of the current water gauge in Děčín. A coincidence regarding the water level (1746) is completely random (Fig. 6). However, there is a noticeable difference in the trend of annual lows of both series. We also emphasised the effect of the overall minima, so the graph also separates the winter minima, which show a downward trend, for example, just before 1746.
It is worth noting that the winter minimum of 1823 is not shown on the Elbe HSs, but in view of the timing it corresponds to the low water levels of the Rhine. The only significant summer minima that are not documented on the HSs in the Czech part of the Elbe are around 1760, 1858 and 1878 (see the Discussion).
Coincidence of annual water level minima at the Děčín station (grey circles) and altitudes measured on the HS1 and HS3 hunger stones in Děčín and Dolní Žleb (red circles).
If we compare the results with the Děčín series, i.e. with
direct measurements in the vicinity of the HS3 hunger stone, the deviations
of the marked and measured annual values are minimal. Until 1957, there are
11 year lows (not counting local minima) which we can evaluate, and eight of them
have a deviation of less than 4 cm. A result of less than 5 cm is detected
for the marks from 1911 (
In conclusion, we can state a good match of the minima detected, which, moreover, are mostly representative of the largest extremes. However, this is not entirely true, as some years such as 1540, 1590 and 1761 are missing. This is a great motivation for the next stage of work.
There is no need to doubt the credibility of the low water level marks in Děčín from 1868 to 1957. When interpreting them, however, it is necessary to know the described changes: whether they are changes in the channel or flow rate enhancement due to the Vltava cascade. These are annual or local minima marked with the greatest possible care. It is also obvious that older marks in the 19th and 18th centuries were made in the same way and with the same intentions. Can this claim be extended to the past, i.e. to the 17th and 16th centuries, and is this finding valid for other hunger stones both in Bohemia and Saxony?
It would probably be appropriate to prove the connection of the high marks in Děčín, Dolní Žleb, Schmilka and Pirna. However, when verifying the relationship between Pirna and Děčín, we can compare only four concurrent records. These are the years 1616, 1707 and 1842. Since we use the relative difference to the water stage in 1842, we can only compare the three remaining heights of 1616, 1707 and 1746. The relationships of 1616, 1707 and 1842 are linear; the water stage in 1746 is somewhat different, where the difference from the expected value is more than 10 cm. Perhaps only a local minimum (LM, not AM) was marked in Pirna. However, we only use the published data from 1842 and 1843, and it is not entirely certain that the commissioners found and surveyed the lowest mark for a given year. Verification is still difficult; we do not see this mark on the current stone in Pirna–Oberposta.
We can recommend further field surveys in future (the next one especially in Dolní Žleb) and the levelling and scanning of other objects, especially the stone in Pirna. For a detailed analysis and a search for remnants of older marks, it is impossible to rely solely on photographic documentation. Comparatively older photographic material (Fig. 8) and detailed inspection of scanned 3D objects are required.
Since we can trust DM epigraphic sources, the only thing that remains is to
point out other published sources from 1842 to 1843. These are compilations of
the measurements by the then commissioners/hydro technicians and possibly
subsequent processing by the Statistical Office of the Kingdom of Saxony or
the Patriotic Economic Society of the Czech Kingdom. They
point to other low levels that we expected and that could not be verified.
This includes, for example, the height of 1590. A report based on the results
of the commission in 1842 and therefore the Protokoll (1842) appeared in
Picture from
An overview of the Saxon DM-type sources (edition of the new series from 1843, Statistik der Gewerbe und Handel, pp. 86–93).
Saxon inches [
If we take this source into account and we combine these data with the data already presented, we find a slight shift in some places, but the overall picture and trend confirm information on the minima of water levels from hunger stones in Bohemia. Another source is the report of the Patriotic Economic Society (Neue Schriften, 1845), where a forester and observer of the Děčín–Podmokly station gave the exact height of the marks (Table 10). This is partly a compilation of the heights from Děčín and Dolní Žleb; the data are very similar or the same (1616, 1707, 1746, 1811, 1835 and 1842). Differences of more than 8 cm are shown only by the DM of 1766, and minor differences are seen in the years 1782, 1790 and 1800. However, there are also data for 1516, 1517 and 1834. To complement the Děčín data, the minima of 1516 and 1517 were mainly used. We assume that, as a forester and a meteorological observer, Adam Seidel could supplement the report of the commissioners (who had only a limited time to survey) from his own examinations in Dolní Žleb and Děčín, where he lived. The years 1516 and especially 1517 were very dry, as evidenced by contemporary descriptions in the Old Czech Chronicles (SLČ, 1941) in particular, describing rather meteorological and phenological parameters of drought (e.g. harvest occurring as early as on 29 June).
In the promotional photographs issued as postcards, we can find supposed minimum marks that do not correspond to the reality (correction in parentheses) such as the years 1745 (1746) and 1858 (1868). The often published postcard with a lady in a hat by Ernst Rennert (as in Brázdil et al., 2015, 2019a) and an article in the regional anthology (Pažourek, 1995) indicate an inscription from 1417 in the left part of the plateau at the river. Is this possibly a misinterpretation or is this a complete forgery? In these places, there is now an inscription from 2003, but there is no indication that there is any mark, not to mention that the date would necessarily have been made using Roman numerals. There were once completely or partially wiped out inscriptions of the minimum of 1904 and the inscription “1904 Weh” (“misery” or “suffering”). These inscriptions have virtually disappeared.
In the river side of Pillnitz Castle, there are signs including a year marking of 1778. By comparison with the mark heights in Magdeburg and the descriptions in documentary sources, it can be considered rather to mark the year of repairing the castle in 1778 or even the anniversary of its founding in 1718. But then it should be marked as 1718.
It is remarkable that we find virtually the same tradition and the same DMs in Děčín and Pirna on the Saxon and the Czech sides. At that time, from the 13th to the beginning of the 15th century, today's Saxon Pirna was part of Bohemia. In 1432 the towns were hit by a catastrophic flood, the height of which is marked in Děčín next to the RG1 rock water gauge. In 1515, Děčín became the property of aristocratic families from neighbouring Saxony, first of the lords of Salhausen and from 1534 onward of Bünau (Schattkowsky, 2003). Until 1628, i.e. for 94 years, this family was in possession of the Děčín and Weesenstein estates in the vicinity of Pirna. At that time, the oldest identified low-level signs of 1536 and 1616 were made on the HS3 stone in Děčín. The low water levels of 1516 and 1517 are only documented in literature (Neue Schriften, 1845), i.e. at the time of the Salhausens. With the beginning of the Thirty Years' War (1618–1648) and the re-catholicisation of Bohemia in 1626, Pirna became the centre of Czech exiles. It is evident that Děčín and Pirna are bound by one river, chain-boat navigation and partly by common history. It is therefore not surprising that we find an analogy in the area of the documentation of flow minima.
The alluvial–pluvial regime of the Rhine predetermines the seasonality of the Rhine minima, which occur rather in autumn and winter. This is mostly later than on the Elbe, where there are mostly summer minima. The very dry period of 1536–1541 is defined particularly by the Elbe and Rhine minima (Table 11a, b). The mark of 1654 in Meissen is known only from literature, in which there are also a number of reports from the Rhine basin. An almost perfect concurrence is represented by the minima of 1766 and 1767. The very warm and dry period of 1790–1794 was evident in both river basins. The lows also coincide in 1800 and 1858. In the Rhine basin, the drought was more significant. In the Elbe River basin, the catastrophic flood changed the situation at the end of July and beginning of August, which affected the upper Elbe basin and mainly the Krkonoše and Krušné Ore Mountain areas (Elleder, 2015).
Compilation of the Czech DMs (Neue Schriften, 1845).
Austrian inches [
Documentation of minimum water levels in the Rhine basin according
to Wittmann (1859) and of the Elbe minima on the basis of documented DMs from
DM – drought mark; DE – Děčín (Table 4); DZ – Dolní Žleb (Table 5); SCH – Schmilka; KO – Königstein; PI – Pirna; ME – Meissen; STA – Stade; Sax – Saxony (Table 9). Other sources in brackets: GBS (Gewerbe Blatt für Sachsen, no. 5, 1843), W (Wittmann,1859), BT (Börngen, Tetzlaff, 2001).
Graphical overview of DM data from the Czech and Saxon areas
A comparison of the duration of the tradition of making minimum markings in the Rhine and Elbe basins does not clearly indicate a longer tradition in either area. What is more interesting is a graphical overview of data from the Czech and Saxon DM sources (Fig. 9). It is apparent that the downward trend pointed out by reputed geographers and water managers (Burghaus, Grebenau, Wex, Harlacher and others) in the measured series has been apparent since about 1746, even at the lows recorded on hunger stones. In the case of Děčín, it is clear that during the coldest period of the LIA, the Maunder Minimum (Eddy, 1976) could have had a positive effect on the Elbe runoff, although, for example, Ogurtsov (2019) illustrates an even deeper minimum in the first half of the 15th century.
Unfortunately, the marks of 1516 and 1517 and their positions are known only through the testimony of Adam Seidl of Děčín and from an indication in the Protokoll (1842). However, the positions of the 1536 and 1616 marks increase their credibility. The downward trend since 1746 in Děčín cannot be explained only by the hypothetical deepening of the profile or as a result of the artificial shortening of the Elbe in the case of Dresden and Magdeburg. The fact that the runoff may have been comparable to the period after 1842 and even lower before the onset of the Maunder Minimum may be useful knowledge about the status of the basic flow and the status of groundwater. In the case of the Rhine, we have very little data available. The existing information, however, does not contradict previous considerations. Again, there are two important time points, the years of 1541 and 1750. The interpretation of other reports on hydrological drought from the Maunder Minimum period is a matter for future studies.
Hunger stones with low water marks are a phenomenon that has been and is regionally limited to the Upper Rhine basin and the Elbe River. In other regional areas, we have not been able to find an analogous activity where, for centuries, minimum water levels have been marked. In the Rhine basin, the water level of Lake Constance (Bodensee) and the Rhine level in the area downstream of the confluence with the Aare River to Cologne were marked. While very few of the former objects with low level marks are available in the Rhine basin, the situation is still favourable in the sandstone part of the Elbe canyon from Děčín to Pirna and its surroundings. There are at least 27 objects on the Czech side and at least 10 stones on the German side, mainly with signs dating mostly from the 20th century. Still, several of them are part of an older tradition prior to 1892 or 1842. Of these, we can only be sure of the stones in Těchlovice, Děčín, Dolní Žleb, Hřensko and Pirna. According to the existing findings, the oldest marks from the 17th and 18th centuries have been preserved only in Děčín and Pirna, even though they used to be in several places, and we are not sure about Dolní Žleb. A number of stones on the navigation route, including the hunger stones, were recommended for blasting by navigation committees in 1842 and 1850.
The situation in Děčín and Pirna in particular is exceptional. It consists of the existence of very old records of minimum water levels and the existence of old records of water levels. In Děčín, moreover, the 590-year-old flood marks and the 490-year-old low water marks are combined in one logical complex. It is evident that the motivation for making the low water marks was related to navigation conditions in the Elbe canyon. In fact, this tradition was made possible by the availability of the local material, sandstone in the form of rocky outcrops or boulders, onto which the marks could easily be cut, engraved or painted. The minimum signs on the individual objects in Děčín are related to the dedicated water gauges and markings of the navigation depth, which was about 93 cm for a half load and 130 cm for full navigability around 1842. The old rock water gauge for high and low water levels and its projection on the first of the three Děčín stones served the safe loading and passing, as well as the subsequent water gauge in the city.
We have shown that the years with marks or crosses are credible evidence of the occurrence of flow rate minima, mostly annual minima. If there were other minima in the year, additional lines were made, forming an occasional water gauge for the given year. Obviously, the originators' efforts were to capture the annual minimum as accurately as possible, and the guarantee of reliability was often their signature, name or initials. The marks correspond to the measured water levels of the systematic series and are relatively representative of the important minima of the Magdeburg 1727–1880 and Děčín 1851–2019 series. The correlation of the 1868, 1892, 1893, 1904, 1911, 1921, 1928, 1930, 1934, 1947 and 1957 markings (DMs) in Děčín with the series of measurements mostly shows a match with differences of less than 4 cm or, exceptionally, greater. Therefore, we assume the same accuracy, i.e. compliance with real minima at the same level, for marks from the 1516–1867 period.
According to the observed water level minima in the 16th and early 17th centuries, the minima were at the same level and probably at an even lower level than in 1842. No completely reliable water level minimum marks are yet available for the Maunder Minimum (MM) period in the Czech territory. The marks of 1654 (Meissen) and 1681 (Königstein) are documented only by more remote literature, and their height is unknown. The exceptions are the marks at the end of the MM in 1706 and 1707. The levelling measurement of the marks on two stones and the creation of a 3D model of the Děčín stone by scanning have helped us to understand the tradition of water level recording, to rehabilitate the value of marks on hunger stones and to bring new, very reliable data on the occurrence of hydrological drought in the historical period.
However, many other questions have also emerged from the survey. The question is not whether it makes sense to document the DMs, but rather how much of the former collection remained after regulating the Elbe and operating chain-boat navigation locally. We are confident that further field and archive research will bring an opportunity to obtain valuable data on hydrological droughts of the past. The profitability of the resources and time spent on exploration and processing is evident.
The input data used for a comparison with the data are presented in Tables 2, 4, 5 and 8. The measured records (Děčín, Dresden and Magdeburg) used in this paper are the property of the Czech Hydrometeorological Institute and are not freely available.
LE prepared the archive and historical sources. LE and LK prepared the field survey and measurement. TK analysed the HS object with MeshLab software, and JŠ worked with GIS applications and prepared maps and illustrations. All the authors participated in the interpretation of the field data and the results.
The authors declare that they have no conflict of interest.
This article is part of the special issue “Droughts over centuries: what can documentary evidence tell us about drought variability, severity and human responses?”. It is not associated with a conference.
We thank Zvonimir Dragoun for the geodetic surveying of the flood marks in 2004 and 2005 along the Elbe between Mělník and Děčín and of the low water marks later in 2015. We give sincere thanks to Oldřich Kotyza from the Litoměřice Museum for numerous friendly consultations and advice, as well as to the director of the museum in Děčín and Vlastimil Pažourek and Hana Slavíčková from the Regional Archive in Děčín for their great willingness to help and for their consultations. It is impossible to imagine our study without the hard work and interest of Randák's team from the Elbe River Administration. The friendly advice and persistent optimism and interest of Zlata Šámalová was a source of valuable information as well as energy. We also thank our colleagues from LfULG Dresden. Last but not least, we thank Václav Dvořák for the translation, Neil Macdonald and an unknown reviewer for their valuable improvements to the text, and Erin Naillon for her excellent help in proofreading the entire document.
This paper was edited by Günter Blöschl and reviewed by Neil Macdonald and one anonymous referee.