Dear authors,
Both referees have judged your manuscript as being of very high quality and very timely – especially in the context of global change and its potential impacts on environmental systems, with a specific focus being set here on the DOC:nitrate ratios. The results presented are relevant not only to the hydrological sciences community, but also beyond that to lowland agricultural catchment managers and stakeholders.
The points put forward by the referees are of minor to moderate character – your responses brought forward during the discussion phase are well aligned with the requests/comments made by the referees.
One specific comment appears particularly useful towards streamlining the ideas and objectives put forward in the introduction, and by picking up then that same sequence through the results and especially the discussion section. This will help to better guide the reader through the entire manuscript.
I look forward to receiving the revised version of your contribution.
Best regards,
Laurent Pfister

Dear authors,
thank you very much for submitting a revised version of your manuscript. The main points pinpointed by the referees have been adequately addressed. Therefore, I have the pleasure to accept your manuscript for final publication in HESS.
Many thanks for having chosen HESS for publishing the outcomes of your research. I look forward to see your manuscript published in its final version.
Best regards,
Laurent Pfister