the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 31 Mar 2026
Changes in groundwater-surface water interactions following two centuries of irrigation practices and groundwater use in the Upper Ganges-Yamuna interfluve, North India.
Abstract. The Indo-Gangetic Basin (IGB) is a global hotspot for groundwater overexploitation. Previous studies have shown that groundwater levels initially rose due to enhanced recharge following the construction of irrigation canals, but subsequently declined as agricultural, municipal, and industrial abstractions intensified. However, the relative impacts of separate recharge and abstraction components (precipitation, canal leakage infiltration, irrigation return flow, and irrigation, municipal and industrial abstraction), remain unclear, as do the effects on groundwater-surface water interactions and environmental flows. This study therefore aims to quantify spatio-temporal changes in groundwater recharge and abstraction components over the past two centuries and assess how these changes have impacted groundwater–surface water interactions in the Upper Ganges–Yamuna interfluve in northern India.
Groundwater model simulations indicate that canal water infiltration following canal construction after 1830 boosted recharge, but since the 1970s increased abstractions have lowered groundwater tables and reduced river exfiltration. Currently irrigation accounts for roughly 85 % of abstractions, with municipal (15 %) and industrial (< 1 %) uses accounting for much smaller shares. From around 2000, abstraction lowered groundwater tables to such an extent that local rivers likely shifted from draining to infiltrating conditions. As a result, groundwater–surface water interactions in local rivers may have fundamentally changed. This shift threatens environmental river flows, degrades surface water quality by limiting wastewater dilution, and harms groundwater quality where polluted river water infiltrates the aquifer, posing risks to both ecosystems and human health. Although both the Yamuna and the Ganges show reduced groundwater exfiltration, they are not (yet) infiltrating.
- Preprint
(1982 KB) - Metadata XML
- BibTeX
- EndNote
Status: open (until 12 May 2026)
- CC1: 'Comment on egusphere-2026-1584', Nima Zafarmomen, 06 Apr 2026 reply
-
RC1: 'Comment on egusphere-2026-1584', Anonymous Referee #1, 16 Apr 2026
reply
General comments
This is a well written paper that presents an interesting historical study on the recharge and water level dynamics of an area of the Indo-Gangetic Basin. The quantification of different sources of recharge over an almost two-hundred-year period using numerical modelling is novel and an important contribution. After moderate revisions I suspect the paper will be suitable for publication.
I have some overarching comments.
The apparent lack of model calibration and validation using in-situ groundwater level data is an important element of the analysis that is missing. Do you have any longer-term groundwater level records at all from this region? I think these would be useful as a sense check to your results. The time series length does not need to be as long as the modelled period, but some slightly longer timeseries data would really help. I think it would be worth trying to find some longer-term data. It is often available offline in local government offices. I would suspect at the very least it should be possible to get some water level data with timeseries staring sometime in the period from the 1950 - 1970s. Even if you can’t get continuous time series data, you could look at regional water level behaviour over a longer period, by collating a slightly more extensive water level dataset. At the very least it would be beneficial to present the groundwater level data you already have, but I do think it should be possible to find a little more longer-term data which would considerably improve the novelty and impact of the paper.
Can you use the groundwater level data you already have to illustrate how your model results compare to observed groundwater level trends during the period data is available?
Does your model account for the distribution canals that provide water to farmers fields? Is this accounted for implicitly in your irrigation return flows? Distribution canals are likely to play a significant role in the spatial variation of canal derived recharge in the region.
As the other reviewer has highlighted the lack of seasonality in your model has implications. For example, whether rivers are receiving or losing depends on the time of year and the range of water level fluctuation experienced in a year. The range of water level fluctuation in this region can be considerable. How might this impact your findings? How does lack of representation of seasonality more generally impact your findings?
You have made quite a lot in the summary and abstract of the threat to drinking water quality from losing rivers, but water quality isn’t something you explicitly model. So it might be worth being a little more cautious in your discussion about this.
Is it possible to present the data you compiled on groundwater abstractions and recharge in the manuscript or an appendix? It would be helpful to see the vector or raster datasets you compiled.
Specific comments
Short summary: the implication that losing waters from rivers to groundwater threatens drinking water supply isn’t inevitable. Without more context in the summary, I would reconsider the weight you attach to this conclusion.
Abstract: You say that ‘local rivers likely shifted from draining to infiltrating conditions’ and that ‘groundwater–surface water interactions in local rivers may have fundamentally changed’. It’s not clear in the abstract whether your model shows this effect explicitly or whether you infer this? It’s clear when reading the rest of the manuscript, but it needs to be made clearer here.
Likewise, the continued role of canals after 1970 is not clear in the abstract. You mention that they boosted recharge prior to 1970 but do they continue to recharge groundwater levels after this period?
Reading on the answers to these questions are clear, but they need to be made clearer in the abstract.
Introduction: arguably water resource development has been going on in the region for much longer than this. The Mughals actively managed water resources and there is evidence as far back as the Indus Valley civilisation of large-scale water resource development. To be more accurate you could say something like, ‘development of modern irrigation canal systems began in 1830 with the Eastern Yamuna irrigation canal’.
Figure 1: The model schematisation does not seem to include the canals. Is that correct?
2.2 MODFLOW 6 – model schematisation: it would be helpful to know why rivers and canals were simulated differently in your model.
2.3 Monte Carlo analysis and validation: How were the groundwater level data used to validate your model? Can you present some plots to show observed versus modelled water level changes?
3.2 Effects on groundwater table: You state that, ‘after 2000, groundwater tables declined further.’ Which appears to be based on Figure 8. However, it appears from Figure 7 that after this period groundwater decline slows and groundwater levels are arguably more stable. It would be helpful to clarify this apparent discrepancy.
Figure 8 and 10: The layout of these figures is quite confusing, I would suggest reconsidering the placement of the ‘natural situation’ and ‘current situation’ plots and their associated legends. At present it appears as if the legend on the left is for the plots it underlies and likewise on the right. However, I think the legend on the left is only for the ‘natural situation’ and ‘current situation’ plots.
4.1 Groundwater balance evolution over the past two centuries in the Upper Ganges-Yamuna interfluve: At the start of this section, you mention that changes in recharge and abstraction influence groundwater levels with a temporal delay, but this is the first time this temporal delay is mentioned. What is the temporal delay for the different recharge sources?
The discrepancy of your results with those observed by MacAllister et al. (2022) could also be related to a much less dense canal network in your study area and less continuous canal development through the 19th and 20th century.
4.2 Model uncertainties and limitations: Is the assumption of stable land use patterns over a nearly two-hundred-year period in this area really justified? This ties into the other reviewer’s comments.
4.3 Implications: It would be helpful to show evidence of the current extent of wastewater inputs to rivers. Do you have any data for this?
5 Conclusions: You conclude by saying unless substantial recharge enhancement occurs groundwater level decline is inevitable. However, India is investing in Managed Aquifer Recharge on a very large scale. It would be worth recognising this in your conclusions and/or discussions.
A.1 Irrigation groundwater demand: Is the 2011 census data the most recent data available? Could you not use consecutive census to better quantify changes with time?
Citation: https://doi.org/10.5194/egusphere-2026-1584-RC1
Data sets
Data and Code: Changes in groundwater-surface water interactions following two centuries of irrigation practices and groundwater use in the Upper Ganges-Yamuna interfluve, North India. Frank J. G. van Broekhoven https://doi.org/10.5281/zenodo.19131621
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 60 | 35 | 10 | 105 | 4 | 5 |
- HTML: 60
- PDF: 35
- XML: 10
- Total: 105
- BibTeX: 4
- EndNote: 5
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
The manuscript presents a valuable and timely contribution to the field of hydrology, particularly in understanding long-term groundwater–surface water (GW-SW) interactions in heavily managed systems. By reconstructing two centuries of hydrological evolution using a physically based MODFLOW 6 framework, the study provides important insights into how irrigation development and groundwater abstraction have reshaped the hydrological regime in the Upper Ganges-Yamuna interfluve.
One of the key strengths of the paper is its long-term perspective (1800–2016), which is rarely achieved in groundwater studies and allows for a comprehensive understanding of system transitions from natural to human-dominated conditions. The integration of multiple recharge and abstraction components (e.g., canal leakage, irrigation return flow, sectoral water use) provides a holistic representation of groundwater balance dynamics, addressing an important gap in previous studies.
Overall, the manuscript is well-structured, methodologically sound, and highly relevant, and it significantly advances knowledge on anthropogenic impacts on groundwater systems. I will put some minor comments:
1) The manuscript assumes temporally constant spatial distributions for several components (e.g., land use, recharge patterns). While this is acknowledged, a brief discussion on how this assumption may affect historical reconstructions would strengthen the study.
2) The use of yearly time steps simplifies the system and excludes seasonal dynamics. A brief justification of why this does not affect key conclusions would be helpful.
3) While uncertainty is addressed through Monte Carlo simulations, a clearer distinction between input uncertainty and structural/model uncertainty would strengthen the discussion.
4) Given the focus on groundwater–surface water interactions, it would be valuable to acknowledge recent work. For example, “Assimilation of Sentinel‐based Leaf Area Index for Modeling Surface–Ground Water Interactions in Irrigation Districts.”
5) The manuscript could benefit from a slightly clearer comparison with previous regional/global groundwater studies to better highlight its novelty.
The manuscript is strong and suitable for publication after minor revisions. The suggested comments mainly aim to improve clarity and strengthen the interpretation rather than requiring substantial additional work.