Perhaps you may explore this journal:

http://e-zbornik.gf.sum.ba/en/

Hi, Anton^ Go to DOAJ.org - choose on the first page 12192 Journals without APC. However, the system brings me to the All 17000+ Titles, so use Refine search checkbox "Without article processing charges (APCs) " You will be sent to 12 030 titles (https://doaj.org/search/journals?source=%7B%22query%22%3A%7B%22bool%22%3A%7B%22must%22%3A%5B%7B%22term%22%3A%7B%22bibjson.apc.has_apc%22%3Afalse%7D%7D%2C%7B%22term%22%3A%7B%22bibjson.other_charges.has_other_charges%22%3Afalse%7D%7D%5D%7D%7D%2C%22size%22%3A50%2C%22sort%22%3A%5B%7B%22created_date%22%3A%7B%22order%22%3A%22desc%22%7D%7D%5D%2C%22track_total_hits%22%3Atrue%7D) where you can search by different fields: All fields, Title, Keywords, Subject, Publisher, Country of Publisher, Language. I used a search: (groundwater or (ground water) ) in All fields and got 74 titles:

Below is the link. I have checked - it works.

Cheers, Irina

(https://doaj.org/search/journals?source=%7B%22query%22%3A%7B%22bool%22%3A%7B%22must%22%3A%5B%7B%22term%22%3A%7B%22bibjson.apc.has_apc%22%3Afalse%7D%7D%2C%7B%22term%22%3A%7B%22bibjson.other_charges.has_other_charges%22%3Afalse%7D%7D%2C%7B%22query_string%22%3A%7B%22query%22%3A%22%5C%5C(groundwater%20OR%20%5C%5C(ground%20water%5C%5C)%5C%5C)%22%2C%22default_operator%22%3A%22AND%22%7D%7D%5D%7D%7D%2C%22size%22%3A50%2C%22sort%22%3A%5B%7B%22created_date%22%3A%7B%22order%22%3A%22desc%22%7D%7D%5D%2C%22track_total_hits%22%3Atrue%7D)

To Irina K. Razumova: thanks for your great answer. For your info e-Zbornik is included in DOAJ directory.

https://doaj.org/toc/2232-9080?source=%7B%22query%22%3A%7B%22bool%22%3A%7B%22must%22%3A%5B%7B%22terms%22%3A%7B%22index.issn.exact%22%3A%5B%222232-9080%22%5D%7D%7D%5D%7D%7D%2C%22size%22%3A100%2C%22sort%22%3A%5B%7B%22created_date%22%3A%7B%22order%22%3A%22desc%22%7D%7D%5D%2C%22_source%22%3A%7B%7D%2C%22track_total_hits%22%3Atrue%7D

In Mexico there are two magazines without payment and indexed in the Web of Science and in Scopus where you can publish about groundwater and they are quarterly, these are: International Geophysics (Geofísica Internacional) and Atmosphere (Atmósfera) published by the National Autonomous University of Mexico.

Thank you all for your valuable information. It will help me a lot.