the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 01 Dec 2021
Changes in paleo-underground water levels revealed by water wells and their relationship with climate variations in imperial China
Abstract. Based on the records of the bottom elevations of 482 ancient water wells collected from published archaeological reports, we reconstructed the paleo-underground water levels (PUWL) in the urban areas of Chengdu, Changsha, Nanjing, Suzhou, Suqian, and Yancheng cities in the vicinity of 30° N in China. The PUWL fluctuations varied between the inland and the coastal regions and their transitional areas. There were four PUWL phases in the inland areas: low in Han (206 B.C.–A.D. 220), high in Tang (A.D. 618–907), low in Song (A.D. 960–1279), and high in Ming (A.D. 1368–1644). In contrast, there were five PUWL phases in the coastal regions: high in Han (206 B.C.–A.D. 220), low in Jin-Northern & Southern Dynasties (A.D. 266–589), high in Tang-Song (A.D. 618–1279), low in Ming (A.D. 1368–1644), and high in Qing-Republic of China (A.D. 1644–1949). Yet, there were no apparent changes in PUWL in the transitional areas between the inland and the coastal regions. Regional hydrological factors cause the geographic variations of the PUWL fluctuations. Precipitation changes drove the rise and fall of PUWL in the inland areas. In contrast, the variations of PUWL in the coastal regions were attributed to the temperature-induced sea-level changes. This study illustrates the potential of using PUWL in tracing paleo-environment changes and their driving factors, which is a novel approach in environmental archaeology.
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RC1: 'Comment on cp-2021-159', Pál Sümegi, 14 Dec 2021
Changes in paleo-underground water levels revealed by water wells and their relationship with climate variations in imperial China
Chenyao Jiang, Xin Jia, Xinggong, Meng Ou, Harry F. Lee
The authors of the manuscript entitled „Changes in paleo-underground water levels revealed by water wells and their relationship with climate variations in imperial China” chose a very important topic and a journal suitable for publication. The method (paleo-underground water levels = PUWL) is suitable for clarifying the selected topic, and the well-documented 482 wells in 9 cities provided statistically interpretable data for the last 2200 years. The authors emphasized well the issue of the critical stage of social development in human history, and this issue was also well addressed, as they took into account the level of groundwater, that ancient civilizations could only disturb to a minimum degree. The obtained values were well evaluated and the selection of the sites was well solved, the cities with a very insignificant number of excavated wells and thus carrying statistical uncertainties were properly separated from their analyses. The most significant value of the manuscript is that, based on wells from different cities, both local and regional comparisons were made, as well as comparisons with written sources, and they concluded their results according to these factors on groundwater-level. It is of great importance that they compared their data with the temperature values of the area, with the arid-wet index. As these comparisons are also presented in figures, the figures are essential and necessary for an understanding of the presented results. The manuscript is an excellent source material that can be developed in many directions and is suitable for global comparison - it will receive a significant number of references if published. Congratulations to the authors.
I accept the MS with minor revision.
Mistakes:
The reference in line 45 (Institute of Archaeology, CASS, 2003 and 2010) does not appear in the reference list, it has to be completed and the abbreviation must also be displayed.
The legend of Figure 1 needs to be improved, as the colour of Yellow Sea and Chinese lakes is completely the same in my pdf version.
I marked the typographical errors in the pdf version of the manuscript, which I also enclose. These must be corrected.
- AC1: 'Reply on RC1', Xin Jia, 24 Jan 2022
-
CC1: 'Comment on cp-2021-159', Jie Fei, 16 Dec 2021
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Citation: https://doi.org/10.5194/cp-2021-159-CC1 -
AC2: 'Reply on CC1', Xin Jia, 25 Jan 2022
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
Response: Thank you very much for providing the comments and suggestions to our manuscript. We have carefully revised our manuscript, and our point-by-point responses are listed below:
1. The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
Response: Thank you very much for your suggestion. Our data were collected from 42 excavation reports, while 12 wells that residents in Nanjing are still using were measured by ourselves. As suggested, we have provided further details of our data sources and added the descriptions of some ancient wells in the revised manuscript (lines 77-80) such that readers could have a better idea about our data. Besides, we have also put down the details of every ancient well in the supplementary information.
2. The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
Response: Thank you for the comment. About the 30N zone, we only used it to delimit our study area. The vicinity of 30°N is known for the abundant records of ancient civilizations, where many people settled in this region in different dynasties. So, many ancient wells could be found in this region, which is very important for this research. Briefly, we investigated the 30N zone owing to the abundance of ancient wells records, and we did not seek to prove that the 30N is the explanatory factor of PUWL. To avoid confusion, we have also clarified this point in the revised manuscript (lines 44-50).
3. The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Response: Thank you for the comment. We agree that the groundwater tables are directly influenced by hydrological factors, such as rivers and lakes. When the volume of rivers and lakes increases, it can also increase groundwater volume and hence, raise the underground water table levels, vice versa. But, it is worth mentioning that the volume of rivers and lakes is ultimately determined by climatic factors such as temperature and precipitation, which influence the total amount of evaporation and rainfall. Therefore, in this research, we seek to illustrate how and in what ways the variations of PUWL could be affected by climate changes.
4. Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Response: Thank you very much for the comment. Previous studies indicated a significant correlation between the PUWL variations and the sea-level fluctuations in the coastal regions (Shen and Zhu, 2004; Sivan et al., 2004). In addition, the fluctuations of sea levels were driven by the temperature changes (Rohling et al., 2009; Siddall et al., 2010; Kopp et al., 2016), as the rising and falling temperatures would lead to the melting and the growth of glaciers and subsequently result in the rise and the fall of sea levels (Clark et al., 2001). The above studies reveal that PUWL in coastal areas is significantly affected by sea-level changes, while temperature changes drive sea-level changes. As the lower reaches of the Yangtze River are located in the coastal areas, we compare the PUWL variations with the temperature changes (instead of precipitation changes). The above point has been further elaborated in the revised manuscript (lines 149-169).
Reference:
Clark, P. U., Mix, A. C. and Bard, E.: Ice sheets and sea level of the Last Glacial Maximum, EOS: Earth Space Sci., 82, 241-247. https://doi.org/10.1029/01EO00133, 2001.
Galili, E., and Nir, Y.: The submerged Pre-Pottery Neolithic water well of Atlit-Yam, Northern Israel, and its palaeoenvironmental implications, Holocene, 3, 265-270, https://doi.org/10.1177/095968369300300309, 1993.
Kopp, R. E., Kemp, A. C., Bittermann, K., Horton, B. P., Donnelly, J. P., Gehrels, W. R., Hay, C. C., Mitrovica, J. X., Morrow, E. D., Rahmstorf, S.: Temperature-driven global sea-level variability in the common era, PNAS, 113, E1434-E1441, https://doi.org/10.1073/pnas.1517056113, 2016.
Nir, Y. and Eldar, I.: Ancient Wells and Their Geoarchaeological Significance in Detecting Tectonics of the Israel Mediterranean Coastline Region, Geology, 15, 3-6, https://doi.org/10.1130/0091-7613(1987)15<3:AWATGS>2.0.CO;2, 1987.
Rohling, E. J., Grant, K., Bolshaw, M., Roberts, A. P., Siddall, M., Hemleben, C. and Kucera, M.: Antarctic temperature and global sea level closely coupled over the past five glacial cycles, Nat. Geosci., 2, 500-504, https://doi.org/10.1038/ngeo557, 2009.
Shen, H. Y. and Zhu, C.: Relationship between the ancient wells and sea-level fluctuation from East Han to Ming Dynasty in Yancheng area, Mar. Geol. Front., 3, 25-29+2, https://doi.org/CNKI:SUN:HYDT.0.2004-03-004, 2004.
Siddall, M., Kaplan, M. R., Schaefer, J. M., Putnam, A., Kelly, M. A. and Goehring, B.: Changing influence of antarctic and greenlandic temperature records on sea-level over the last glacial cycle, Quat. Sci. Rev., 29, 410-423, https://doi.org/10.1016/j.quascirev.20 09.11.007, 2010.
Sivan, D., Lambeck, K., Toueg, R., Raban, A., Porath, Y. and Shirman, B.: Ancient coastal wells of Caesarea Maritima, Israel, an indicator for relative sea level changes during the last 2000 years, Earth Planet. Sci. Lett., 222, 315-330, https://doi.org/10.1016/j.epsl.2004.02.007, 2004.
Sivan, D., Wdowinski, S., Lambeck, K., Galili, E. and Raban, A.: Holocene sea-level changes along the Mediterranean coast of Israel, based on archaeological observations and numerical model, Palaeogeogr. Palaeoclimatol. Palaeoecol., 167, 101-117, https://doi.org/ 10.1016/s0031-0182(00)00234-0, 2001.
Citation: https://doi.org/10.5194/cp-2021-159-AC2
-
AC2: 'Reply on CC1', Xin Jia, 25 Jan 2022
-
CC2: 'Comment on cp-2021-159', Jie Fei, 16 Dec 2021
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Citation: https://doi.org/10.5194/cp-2021-159-CC2 -
AC3: 'Reply on CC2', Xin Jia, 25 Jan 2022
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
Response: Thank you very much for providing the comments and suggestions to our manuscript. We have carefully revised our manuscript, and our point-by-point responses are listed below:
1. The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
Response: Thank you very much for your suggestion. Our data were collected from 42 excavation reports, while 12 wells that residents in Nanjing are still using were measured by ourselves. As suggested, we have provided further details of our data sources and added the descriptions of some ancient wells in the revised manuscript (lines 77-80) such that readers could have a better idea about our data. Besides, we have also put down the details of every ancient well in the supplementary information.
2. The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
Response: Thank you for the comment. About the 30N zone, we only used it to delimit our study area. The vicinity of 30°N is known for the abundant records of ancient civilizations, where many people settled in this region in different dynasties. So, many ancient wells could be found in this region, which is very important for this research. Briefly, we investigated the 30N zone owing to the abundance of ancient wells records, and we did not seek to prove that the 30N is the explanatory factor of PUWL. To avoid confusion, we have also clarified this point in the revised manuscript (lines 44-50).
3. The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Response: Thank you for the comment. We agree that the groundwater tables are directly influenced by hydrological factors, such as rivers and lakes. When the volume of rivers and lakes increases, it can also increase groundwater volume and hence, raise the underground water table levels, vice versa. But, it is worth mentioning that the volume of rivers and lakes is ultimately determined by climatic factors such as temperature and precipitation, which influence the total amount of evaporation and rainfall. Therefore, in this research, we seek to illustrate how and in what ways the variations of PUWL could be affected by climate changes.
4. Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Response: Thank you very much for the comment. Previous studies indicated a significant correlation between the PUWL variations and the sea-level fluctuations in the coastal regions (Shen and Zhu, 2004; Sivan et al., 2004). In addition, the fluctuations of sea levels were driven by the temperature changes (Rohling et al., 2009; Siddall et al., 2010; Kopp et al., 2016), as the rising and falling temperatures would lead to the melting and the growth of glaciers and subsequently result in the rise and the fall of sea levels (Clark et al., 2001). The above studies reveal that PUWL in coastal areas is significantly affected by sea-level changes, while temperature changes drive sea-level changes. As the lower reaches of the Yangtze River are located in the coastal areas, we compare the PUWL variations with the temperature changes (instead of precipitation changes). The above point has been further elaborated in the revised manuscript (lines 149-169).
Reference:
Clark, P. U., Mix, A. C. and Bard, E.: Ice sheets and sea level of the Last Glacial Maximum, EOS: Earth Space Sci., 82, 241-247. https://doi.org/10.1029/01EO00133, 2001.
Galili, E., and Nir, Y.: The submerged Pre-Pottery Neolithic water well of Atlit-Yam, Northern Israel, and its palaeoenvironmental implications, Holocene, 3, 265-270, https://doi.org/10.1177/095968369300300309, 1993.
Kopp, R. E., Kemp, A. C., Bittermann, K., Horton, B. P., Donnelly, J. P., Gehrels, W. R., Hay, C. C., Mitrovica, J. X., Morrow, E. D., Rahmstorf, S.: Temperature-driven global sea-level variability in the common era, PNAS, 113, E1434-E1441, https://doi.org/10.1073/pnas.1517056113, 2016.
Nir, Y. and Eldar, I.: Ancient Wells and Their Geoarchaeological Significance in Detecting Tectonics of the Israel Mediterranean Coastline Region, Geology, 15, 3-6, https://doi.org/10.1130/0091-7613(1987)15<3:AWATGS>2.0.CO;2, 1987.
Rohling, E. J., Grant, K., Bolshaw, M., Roberts, A. P., Siddall, M., Hemleben, C. and Kucera, M.: Antarctic temperature and global sea level closely coupled over the past five glacial cycles, Nat. Geosci., 2, 500-504, https://doi.org/10.1038/ngeo557, 2009.
Shen, H. Y. and Zhu, C.: Relationship between the ancient wells and sea-level fluctuation from East Han to Ming Dynasty in Yancheng area, Mar. Geol. Front., 3, 25-29+2, https://doi.org/CNKI:SUN:HYDT.0.2004-03-004, 2004.
Siddall, M., Kaplan, M. R., Schaefer, J. M., Putnam, A., Kelly, M. A. and Goehring, B.: Changing influence of antarctic and greenlandic temperature records on sea-level over the last glacial cycle, Quat. Sci. Rev., 29, 410-423, https://doi.org/10.1016/j.quascirev.20 09.11.007, 2010.
Sivan, D., Lambeck, K., Toueg, R., Raban, A., Porath, Y. and Shirman, B.: Ancient coastal wells of Caesarea Maritima, Israel, an indicator for relative sea level changes during the last 2000 years, Earth Planet. Sci. Lett., 222, 315-330, https://doi.org/10.1016/j.epsl.2004.02.007, 2004.
Sivan, D., Wdowinski, S., Lambeck, K., Galili, E. and Raban, A.: Holocene sea-level changes along the Mediterranean coast of Israel, based on archaeological observations and numerical model, Palaeogeogr. Palaeoclimatol. Palaeoecol., 167, 101-117, https://doi.org/ 10.1016/s0031-0182(00)00234-0, 2001.
Citation: https://doi.org/10.5194/cp-2021-159-AC3
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AC3: 'Reply on CC2', Xin Jia, 25 Jan 2022
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RC2: 'Comment on cp-2021-159', Neil Macdonald, 19 Dec 2021
The use of wells as a proxy for groundwater availability and therefore as a climate indicator is novel and therefore I was excited to review this paper.
The use of well bottom depth is to my knowledge an innovative and interesting approach to detailing past water levels, however they require critical assessment, considering a number of factors, such as do the well bottoms reflect original construction depths, or might they have been excavated several times, as required when water levels dropped further, it also requires an assumption that the recharge in the well was consistent through time and then this was sufficient to meet supply, if demand changes (i.e. population growth) then it may have been necessary to increase the depth. I also expected some discussion of the local hydrogeology at the sites of study to determine whether conditions were similar or comparable, discussion of lag from precipitation to groundwater level and sensitivity to droughts, possibly using contemporary evidence. Unfortunately none of this was sufficiently explained, as such the principles of using wells as a water table proxy are assumed and not evidenced, as this is a ‘novel’ approach this is a fundamental requirement. You need to convince the reader, therefore much greater explanation and justification is required for each of the sites studied.
I was interested to see how the wells wound be dated, however I am still uncertain, whether these are assigned to dynasties or dated with geo-chronological approaches, I suspect the former, if so this presents challenges in understanding the figures presented. Fig 2 presents the depth and ages of the wells, dynasties across the top, calendar years across the bottom. Therefore I assume that the order that the wells are presented in is meaningful, and that some dating is undertaken? How was this achieved, you must explain this. Similarly the use of dynasties of varying length is challenging when comparing across time, as some long dynasties appear to have trends within these periods e.g. Chengdu – Tang period with increasing depth to the wells towards the end of the period, as such presenting this with a single point is unhelpful.
Greater explanation of the methods used to date and organise the wells and potential uncertainties in ages needs to be discussed. You need to discuss the local hydrogeological conditions in more detail, what is the lag time to drawdown/recharge of the well. You discuss historical events, but these are of limited meaning without basic site information.
You include some short or patchy series, remove these from your discussion they offer little e.g. Ezhou. You present little discussion of data/well densities, this has important implications, as new wells impact on older wells if in similar areas, drawing down local water levels. This is needed so that the reader can understand your approaches to data quality in a novel approach such as this.
I found your attempt to group the sites together disconcerting, why would Chengdu and Changsha respond or record similar trends, they are >750km away from each other and potentially driven by different climatic processes, in different hydrogeological regions? They certainly have different precipitation patterns (average precip. of ~850mma-1 at Chengdu, ~1800 at Changsha mma-1). It was unclear to me why you attempted to create artificial regions (coastal, inland and transitional).
I found that much of the discussion was unfounded and focused on attempting to assign attribution to ‘trends’ or ‘patterns’ in the data that simply were not clearly evidenced. These were not statistically or robustly presented, nor justified. I actually felt that this was beyond the scope of the paper, you need to convince the reader first of the robustness of your approach, that should be the focus of the paper.
Overall I was disappointed, I believe you fail to demonstrate and justify the use of wells as a tool for understanding past climates, however I still beleive there is considerable potential here, therefore the attempt to assign attribution to these changes is unsupported. The idea is novel but is not discussed sufficiently to demonstrate with confidence that it could result in meaningful data, nor could the reader based on this paper replicate your study within another region.
An annotated copy of the manuscript is attached.
- AC4: 'Reply on RC2', Xin Jia, 25 Jan 2022
Status: closed
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RC1: 'Comment on cp-2021-159', Pál Sümegi, 14 Dec 2021
Changes in paleo-underground water levels revealed by water wells and their relationship with climate variations in imperial China
Chenyao Jiang, Xin Jia, Xinggong, Meng Ou, Harry F. Lee
The authors of the manuscript entitled „Changes in paleo-underground water levels revealed by water wells and their relationship with climate variations in imperial China” chose a very important topic and a journal suitable for publication. The method (paleo-underground water levels = PUWL) is suitable for clarifying the selected topic, and the well-documented 482 wells in 9 cities provided statistically interpretable data for the last 2200 years. The authors emphasized well the issue of the critical stage of social development in human history, and this issue was also well addressed, as they took into account the level of groundwater, that ancient civilizations could only disturb to a minimum degree. The obtained values were well evaluated and the selection of the sites was well solved, the cities with a very insignificant number of excavated wells and thus carrying statistical uncertainties were properly separated from their analyses. The most significant value of the manuscript is that, based on wells from different cities, both local and regional comparisons were made, as well as comparisons with written sources, and they concluded their results according to these factors on groundwater-level. It is of great importance that they compared their data with the temperature values of the area, with the arid-wet index. As these comparisons are also presented in figures, the figures are essential and necessary for an understanding of the presented results. The manuscript is an excellent source material that can be developed in many directions and is suitable for global comparison - it will receive a significant number of references if published. Congratulations to the authors.
I accept the MS with minor revision.
Mistakes:
The reference in line 45 (Institute of Archaeology, CASS, 2003 and 2010) does not appear in the reference list, it has to be completed and the abbreviation must also be displayed.
The legend of Figure 1 needs to be improved, as the colour of Yellow Sea and Chinese lakes is completely the same in my pdf version.
I marked the typographical errors in the pdf version of the manuscript, which I also enclose. These must be corrected.
- AC1: 'Reply on RC1', Xin Jia, 24 Jan 2022
-
CC1: 'Comment on cp-2021-159', Jie Fei, 16 Dec 2021
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Citation: https://doi.org/10.5194/cp-2021-159-CC1 -
AC2: 'Reply on CC1', Xin Jia, 25 Jan 2022
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
Response: Thank you very much for providing the comments and suggestions to our manuscript. We have carefully revised our manuscript, and our point-by-point responses are listed below:
1. The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
Response: Thank you very much for your suggestion. Our data were collected from 42 excavation reports, while 12 wells that residents in Nanjing are still using were measured by ourselves. As suggested, we have provided further details of our data sources and added the descriptions of some ancient wells in the revised manuscript (lines 77-80) such that readers could have a better idea about our data. Besides, we have also put down the details of every ancient well in the supplementary information.
2. The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
Response: Thank you for the comment. About the 30N zone, we only used it to delimit our study area. The vicinity of 30°N is known for the abundant records of ancient civilizations, where many people settled in this region in different dynasties. So, many ancient wells could be found in this region, which is very important for this research. Briefly, we investigated the 30N zone owing to the abundance of ancient wells records, and we did not seek to prove that the 30N is the explanatory factor of PUWL. To avoid confusion, we have also clarified this point in the revised manuscript (lines 44-50).
3. The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Response: Thank you for the comment. We agree that the groundwater tables are directly influenced by hydrological factors, such as rivers and lakes. When the volume of rivers and lakes increases, it can also increase groundwater volume and hence, raise the underground water table levels, vice versa. But, it is worth mentioning that the volume of rivers and lakes is ultimately determined by climatic factors such as temperature and precipitation, which influence the total amount of evaporation and rainfall. Therefore, in this research, we seek to illustrate how and in what ways the variations of PUWL could be affected by climate changes.
4. Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Response: Thank you very much for the comment. Previous studies indicated a significant correlation between the PUWL variations and the sea-level fluctuations in the coastal regions (Shen and Zhu, 2004; Sivan et al., 2004). In addition, the fluctuations of sea levels were driven by the temperature changes (Rohling et al., 2009; Siddall et al., 2010; Kopp et al., 2016), as the rising and falling temperatures would lead to the melting and the growth of glaciers and subsequently result in the rise and the fall of sea levels (Clark et al., 2001). The above studies reveal that PUWL in coastal areas is significantly affected by sea-level changes, while temperature changes drive sea-level changes. As the lower reaches of the Yangtze River are located in the coastal areas, we compare the PUWL variations with the temperature changes (instead of precipitation changes). The above point has been further elaborated in the revised manuscript (lines 149-169).
Reference:
Clark, P. U., Mix, A. C. and Bard, E.: Ice sheets and sea level of the Last Glacial Maximum, EOS: Earth Space Sci., 82, 241-247. https://doi.org/10.1029/01EO00133, 2001.
Galili, E., and Nir, Y.: The submerged Pre-Pottery Neolithic water well of Atlit-Yam, Northern Israel, and its palaeoenvironmental implications, Holocene, 3, 265-270, https://doi.org/10.1177/095968369300300309, 1993.
Kopp, R. E., Kemp, A. C., Bittermann, K., Horton, B. P., Donnelly, J. P., Gehrels, W. R., Hay, C. C., Mitrovica, J. X., Morrow, E. D., Rahmstorf, S.: Temperature-driven global sea-level variability in the common era, PNAS, 113, E1434-E1441, https://doi.org/10.1073/pnas.1517056113, 2016.
Nir, Y. and Eldar, I.: Ancient Wells and Their Geoarchaeological Significance in Detecting Tectonics of the Israel Mediterranean Coastline Region, Geology, 15, 3-6, https://doi.org/10.1130/0091-7613(1987)15<3:AWATGS>2.0.CO;2, 1987.
Rohling, E. J., Grant, K., Bolshaw, M., Roberts, A. P., Siddall, M., Hemleben, C. and Kucera, M.: Antarctic temperature and global sea level closely coupled over the past five glacial cycles, Nat. Geosci., 2, 500-504, https://doi.org/10.1038/ngeo557, 2009.
Shen, H. Y. and Zhu, C.: Relationship between the ancient wells and sea-level fluctuation from East Han to Ming Dynasty in Yancheng area, Mar. Geol. Front., 3, 25-29+2, https://doi.org/CNKI:SUN:HYDT.0.2004-03-004, 2004.
Siddall, M., Kaplan, M. R., Schaefer, J. M., Putnam, A., Kelly, M. A. and Goehring, B.: Changing influence of antarctic and greenlandic temperature records on sea-level over the last glacial cycle, Quat. Sci. Rev., 29, 410-423, https://doi.org/10.1016/j.quascirev.20 09.11.007, 2010.
Sivan, D., Lambeck, K., Toueg, R., Raban, A., Porath, Y. and Shirman, B.: Ancient coastal wells of Caesarea Maritima, Israel, an indicator for relative sea level changes during the last 2000 years, Earth Planet. Sci. Lett., 222, 315-330, https://doi.org/10.1016/j.epsl.2004.02.007, 2004.
Sivan, D., Wdowinski, S., Lambeck, K., Galili, E. and Raban, A.: Holocene sea-level changes along the Mediterranean coast of Israel, based on archaeological observations and numerical model, Palaeogeogr. Palaeoclimatol. Palaeoecol., 167, 101-117, https://doi.org/ 10.1016/s0031-0182(00)00234-0, 2001.
Citation: https://doi.org/10.5194/cp-2021-159-AC2
-
AC2: 'Reply on CC1', Xin Jia, 25 Jan 2022
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CC2: 'Comment on cp-2021-159', Jie Fei, 16 Dec 2021
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Citation: https://doi.org/10.5194/cp-2021-159-CC2 -
AC3: 'Reply on CC2', Xin Jia, 25 Jan 2022
The idea of this paper is quite novel and it is potentially suitable for CP, however the introduction of the data and the interpretation are not enough. My major concerns are as following,
Response: Thank you very much for providing the comments and suggestions to our manuscript. We have carefully revised our manuscript, and our point-by-point responses are listed below:
1. The introduction of the data sources is too brief, and should be strengthen. Maybe a few examples of the original data source would be helpful for readers to better understand them.
Response: Thank you very much for your suggestion. Our data were collected from 42 excavation reports, while 12 wells that residents in Nanjing are still using were measured by ourselves. As suggested, we have provided further details of our data sources and added the descriptions of some ancient wells in the revised manuscript (lines 77-80) such that readers could have a better idea about our data. Besides, we have also put down the details of every ancient well in the supplementary information.
2. The authors emphasised the 30N zone, but actually no evidence indicated the water levels changes of wells were related to the latitude 30N.
Response: Thank you for the comment. About the 30N zone, we only used it to delimit our study area. The vicinity of 30°N is known for the abundant records of ancient civilizations, where many people settled in this region in different dynasties. So, many ancient wells could be found in this region, which is very important for this research. Briefly, we investigated the 30N zone owing to the abundance of ancient wells records, and we did not seek to prove that the 30N is the explanatory factor of PUWL. To avoid confusion, we have also clarified this point in the revised manuscript (lines 44-50).
3. The direct cause of the variations of water levels of wells should be hydrology. Hydrology should be discussed on various scales, including channel change of rivers and desiccation/expansion of lakes.
Response: Thank you for the comment. We agree that the groundwater tables are directly influenced by hydrological factors, such as rivers and lakes. When the volume of rivers and lakes increases, it can also increase groundwater volume and hence, raise the underground water table levels, vice versa. But, it is worth mentioning that the volume of rivers and lakes is ultimately determined by climatic factors such as temperature and precipitation, which influence the total amount of evaporation and rainfall. Therefore, in this research, we seek to illustrate how and in what ways the variations of PUWL could be affected by climate changes.
4. Another major cause should be precipitation, and it should be helpful to compare the ancient wells in the lower reaches of Yangtze River with local and regional precipitation chronologies, instead of the temperature chronologies.
Response: Thank you very much for the comment. Previous studies indicated a significant correlation between the PUWL variations and the sea-level fluctuations in the coastal regions (Shen and Zhu, 2004; Sivan et al., 2004). In addition, the fluctuations of sea levels were driven by the temperature changes (Rohling et al., 2009; Siddall et al., 2010; Kopp et al., 2016), as the rising and falling temperatures would lead to the melting and the growth of glaciers and subsequently result in the rise and the fall of sea levels (Clark et al., 2001). The above studies reveal that PUWL in coastal areas is significantly affected by sea-level changes, while temperature changes drive sea-level changes. As the lower reaches of the Yangtze River are located in the coastal areas, we compare the PUWL variations with the temperature changes (instead of precipitation changes). The above point has been further elaborated in the revised manuscript (lines 149-169).
Reference:
Clark, P. U., Mix, A. C. and Bard, E.: Ice sheets and sea level of the Last Glacial Maximum, EOS: Earth Space Sci., 82, 241-247. https://doi.org/10.1029/01EO00133, 2001.
Galili, E., and Nir, Y.: The submerged Pre-Pottery Neolithic water well of Atlit-Yam, Northern Israel, and its palaeoenvironmental implications, Holocene, 3, 265-270, https://doi.org/10.1177/095968369300300309, 1993.
Kopp, R. E., Kemp, A. C., Bittermann, K., Horton, B. P., Donnelly, J. P., Gehrels, W. R., Hay, C. C., Mitrovica, J. X., Morrow, E. D., Rahmstorf, S.: Temperature-driven global sea-level variability in the common era, PNAS, 113, E1434-E1441, https://doi.org/10.1073/pnas.1517056113, 2016.
Nir, Y. and Eldar, I.: Ancient Wells and Their Geoarchaeological Significance in Detecting Tectonics of the Israel Mediterranean Coastline Region, Geology, 15, 3-6, https://doi.org/10.1130/0091-7613(1987)15<3:AWATGS>2.0.CO;2, 1987.
Rohling, E. J., Grant, K., Bolshaw, M., Roberts, A. P., Siddall, M., Hemleben, C. and Kucera, M.: Antarctic temperature and global sea level closely coupled over the past five glacial cycles, Nat. Geosci., 2, 500-504, https://doi.org/10.1038/ngeo557, 2009.
Shen, H. Y. and Zhu, C.: Relationship between the ancient wells and sea-level fluctuation from East Han to Ming Dynasty in Yancheng area, Mar. Geol. Front., 3, 25-29+2, https://doi.org/CNKI:SUN:HYDT.0.2004-03-004, 2004.
Siddall, M., Kaplan, M. R., Schaefer, J. M., Putnam, A., Kelly, M. A. and Goehring, B.: Changing influence of antarctic and greenlandic temperature records on sea-level over the last glacial cycle, Quat. Sci. Rev., 29, 410-423, https://doi.org/10.1016/j.quascirev.20 09.11.007, 2010.
Sivan, D., Lambeck, K., Toueg, R., Raban, A., Porath, Y. and Shirman, B.: Ancient coastal wells of Caesarea Maritima, Israel, an indicator for relative sea level changes during the last 2000 years, Earth Planet. Sci. Lett., 222, 315-330, https://doi.org/10.1016/j.epsl.2004.02.007, 2004.
Sivan, D., Wdowinski, S., Lambeck, K., Galili, E. and Raban, A.: Holocene sea-level changes along the Mediterranean coast of Israel, based on archaeological observations and numerical model, Palaeogeogr. Palaeoclimatol. Palaeoecol., 167, 101-117, https://doi.org/ 10.1016/s0031-0182(00)00234-0, 2001.
Citation: https://doi.org/10.5194/cp-2021-159-AC3
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AC3: 'Reply on CC2', Xin Jia, 25 Jan 2022
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RC2: 'Comment on cp-2021-159', Neil Macdonald, 19 Dec 2021
The use of wells as a proxy for groundwater availability and therefore as a climate indicator is novel and therefore I was excited to review this paper.
The use of well bottom depth is to my knowledge an innovative and interesting approach to detailing past water levels, however they require critical assessment, considering a number of factors, such as do the well bottoms reflect original construction depths, or might they have been excavated several times, as required when water levels dropped further, it also requires an assumption that the recharge in the well was consistent through time and then this was sufficient to meet supply, if demand changes (i.e. population growth) then it may have been necessary to increase the depth. I also expected some discussion of the local hydrogeology at the sites of study to determine whether conditions were similar or comparable, discussion of lag from precipitation to groundwater level and sensitivity to droughts, possibly using contemporary evidence. Unfortunately none of this was sufficiently explained, as such the principles of using wells as a water table proxy are assumed and not evidenced, as this is a ‘novel’ approach this is a fundamental requirement. You need to convince the reader, therefore much greater explanation and justification is required for each of the sites studied.
I was interested to see how the wells wound be dated, however I am still uncertain, whether these are assigned to dynasties or dated with geo-chronological approaches, I suspect the former, if so this presents challenges in understanding the figures presented. Fig 2 presents the depth and ages of the wells, dynasties across the top, calendar years across the bottom. Therefore I assume that the order that the wells are presented in is meaningful, and that some dating is undertaken? How was this achieved, you must explain this. Similarly the use of dynasties of varying length is challenging when comparing across time, as some long dynasties appear to have trends within these periods e.g. Chengdu – Tang period with increasing depth to the wells towards the end of the period, as such presenting this with a single point is unhelpful.
Greater explanation of the methods used to date and organise the wells and potential uncertainties in ages needs to be discussed. You need to discuss the local hydrogeological conditions in more detail, what is the lag time to drawdown/recharge of the well. You discuss historical events, but these are of limited meaning without basic site information.
You include some short or patchy series, remove these from your discussion they offer little e.g. Ezhou. You present little discussion of data/well densities, this has important implications, as new wells impact on older wells if in similar areas, drawing down local water levels. This is needed so that the reader can understand your approaches to data quality in a novel approach such as this.
I found your attempt to group the sites together disconcerting, why would Chengdu and Changsha respond or record similar trends, they are >750km away from each other and potentially driven by different climatic processes, in different hydrogeological regions? They certainly have different precipitation patterns (average precip. of ~850mma-1 at Chengdu, ~1800 at Changsha mma-1). It was unclear to me why you attempted to create artificial regions (coastal, inland and transitional).
I found that much of the discussion was unfounded and focused on attempting to assign attribution to ‘trends’ or ‘patterns’ in the data that simply were not clearly evidenced. These were not statistically or robustly presented, nor justified. I actually felt that this was beyond the scope of the paper, you need to convince the reader first of the robustness of your approach, that should be the focus of the paper.
Overall I was disappointed, I believe you fail to demonstrate and justify the use of wells as a tool for understanding past climates, however I still beleive there is considerable potential here, therefore the attempt to assign attribution to these changes is unsupported. The idea is novel but is not discussed sufficiently to demonstrate with confidence that it could result in meaningful data, nor could the reader based on this paper replicate your study within another region.
An annotated copy of the manuscript is attached.
- AC4: 'Reply on RC2', Xin Jia, 25 Jan 2022
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