Agricultural Irrigation Effects on Hydrological Processes in the United States Northern High Plains Aquifer Simulated by the Coupled SWAT-MODFLOW System

Round 1

Reviewer 1 Report

I think the manuscript is exciting, but some comments can improve it.

 

-        More quantitative results should be presented in the abstract.

-        More descriptions of water supply and consumption in the study area can be added to the text.

-        It is needed to explain the interaction water budget in the study area.

-        The boundary condition of the study area should be presented more clearly.

-        The mean absolute error and mean bias error should be reported.

-        The introduction can be elaborated on considering newly published papers.

-        I think the following manuscripts can improve the literature review:

Spatial estimation of aquifer’s hydraulic parameters by a combination of borehole data and inverse solution

 

Simulation of groundwater level in a coastal aquifer

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments: The authors have assessed the performance of the coupled SWAT-MODFLOW models in the US Northern High Plains aquifer under two irrigation scenarios based on: plant water stress and well pumping rates. Although the paper is well written and structured, and the discussion section is detailed and supported by studies carried out, I think it requires a change of approach because most of the current  methodology applied has been previously used in other studies, providing only as a novelty the study case, which should not be the main goal of the paper. Introduction section is mainly focused in groundwater depletions in this aquifer more than in the methodology used in recent similar research  or other models different from the finally used. Furthermore, the two scenarios are not clearly enough and authors must emphasize the opportunities, objectives and differences in simulating them and the environemntal and economic consequences, without which the study seems local and incomplete. However, if the provided novelty is the modification of coupled SWAT-MODFLOW in order to increase capacity of simulation of irrigating scenarios, authors should develop this issue, which is not sufficiently described in the current version of the paper. 

Specific comments:

Lines 22-23:  "The Auto-Irr generally outperformed the Well-Irr.... " In which sense?? Provide specific examples of the percentages of improvements.

Line 50: "... declined from 1940 to 1980 annually..."Indicate percentage of variation.

Line 51: Replace Also by Furthermore (I suggest)

Lines 70-71:"...the two models were coupled into a SWAT-MODFLOW framework.." Discuss recent studies of coupling-models different from the selected one and reasons to use that one.

LInes 79-80, 83-84: "....and make multiple changes to the SWAT-MODFLOW..." This should be the heart of the paper but more (than necessary) attention is paid to the aquifer.

Figure 1b: Different colours for barren land and pasture.... can´t differentiate.

Line 153: Describe briefly the main considerations of the model.

Lines 168-172: not clear enough the scenarios. Reformulate in order to better explain both of them.

Lines 178-179: In Supplementary material there are only 4 images.

Lines 180-181: Describe briefly...... Methods are referenced to previous reseach, so is there no novelty in application???

Lines 206-207: "these studies indicate that the coupled model improved 206 the hydrological simulation compared to the SWAT model...", so which is the novelty of the study? Application in the region?

Lines 210-211: "...each year new irrigation wells are added, and some existing wells are decommissioned." How? Criteria?

Lines 241-242: ".. annual groundwater irrigation volume estimated by the model was comparable with the known USGS estimates in the NHP..." What do you mean? Reformulate.

Lines 243-244: "...until the groundwater irrigation volume was satisfactorily simulated." What does it mean?

Line 266: add references for R2 acceptable.

Lines 647-648: follow references journal´s rules (CAPITAL LETTERS)

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have addressed all my recomendations and I think the paper is ready to be published now.