he high scientific standards maintained by Hydrology Research in its papers owe much to the continuing dedication of the journal's reviewers, who give freely of their time and expertise. IWA Publishing is pleased to pay tribute to this contribution by recognizing those who have participated in the review process. Thus, the Editors of Hydrology Research acknowledge with particular gratitude the following reviewers who have reviewed papers during the period January 2018–December 2018.
| Laura Alakukku | Saeid Eslamian | Medhi Komasi | Muthiah Perumal | Danielle Verdon-Kidd |
| Abdelziz Al-Bassam | Csilla Farkas | Adam Krajewski | Mikolaj Piniewski | Przemyslaw Wachniew |
| Rene Albouy | Vincent Fortin | Ewa Krogulec | Heini Postila | Andrzej Walega |
| Moutaz Al-Dabbas | Guangtao Fu | Xijun Lai | Om Prakash | Dingbao Wang |
| Mohd Yawar Ali Khan | Tian Fuqiang | Joo-Heon Lee | Ilaria Prosdocimi | Dong Wang |
| Nino Amvrosiadi | Guangyao Gao | Huimin Lei | Inmaculada Pulido | Gangsheng Wang |
| Gholamreza Andalib | Hongkai Gao | Fadong Li | Khalid Qahman | Guo-Qing Wang |
| Junhong Bai | Sigurdur Gardarsson | Jianzhu Li | Jianxiu Qiu | Hongqan Wang |
| Xiaoyan Bai | Philip Gassman | Lanhi Li | Zhongyi Qu | Jida Wang |
| Victoria Bassett | Mahesh Gautam | Weiyue Li | Nevil Quinn | Jun Wang |
| Lars Bengtsson | Bahram Gharabaghi | Yanzhong Li | K. Srinivasa Raju | Ryan Webb |
| Giacomo Bertoldi | Lebing Gong | Yi Li | Audil Rashid | Harry West |
| Birendra Bharti | Yicheng Gong | Zhenwei Li | Paolo Reggiani | René Wijngaard |
| Ghosh Bobba | Mark Grismer | Zhi Li | Jonathan Remo | Robert Wilby |
| Hossein Bonakdari | Shixiang Gu | Carlos Lima | Pekka Rossi | Florian Willkover |
| Martijn Booij | Yavuz Selim Güçlü | Kairong Lin | Ole Rössler | John Wilson |
| Alistair Borthwick | Leicheng Guo | Timothy Link | Emmanuel Roulin | Ming-ko Woo |
| Oddbjørn Bruland | David Gustafsson | Dedi Liu | Kiyoumars Roushangar | shiang-jen wu |
| James Buttle | Sasha Han | Dengfeng Liu | Dario Sacco | Bartłomiej Wyzga |
| Mariza Cabral | Nilgun Harmancioglu | Gang Liu | Mojtaba Sadegh | Xianhong Xie |
| Eric Calais | Andreas Hartmann | Hailong Liu | Bhabagrahi Sahoo | Zhenghui Xie |
| Guoliang Cao | Younggu Her | Jintao Liu | Lodovic Salomon | Lihua Xiong |
| Roser Casas-Mulet | Aida Hosseini Baghanam | Maofeng Liu | Jan Seibert | Chong-Yu Xu |
| Chandramouli Chandramouli | Jingming Hou | Denes Loczy | Shahaboddin Shamshirband | Youpeng Xu |
| Fi-John Chang | Zengyun Hu | Eliisa Lotsari | Quanxi Shao | Yueping Xu |
| Saroj Kumar Chapagain | Shengzhi Huang | Chen Lu | Jian Shen | Daqing Yang |
| Nick Chappell | Zailin Huo | Fan Lu | Zhenyao Shen | Hanbo Yang |
| Jean-Baptiste Charlier | Jari Hyvaluoma | Ning Ma | Jenq-Tzong Shiau | T Yang |
| K.W. Chau | Eun Soon Im | Deepesh Machiwal | Jalal Shiri | Zaher Yaseen |
| Henry Wai Chau | Seiichiro Ioka | Judit Madl-Szonyi | Keegan Smith | Aizhong Ye |
| Tao Che | Reza Jahanshahi | Rajib Maity | Ľubomír Solín | Xuchun Ye |
| Xi Chen | Richard Janowicz | Maysam Majidi | Jinxi Song | Tien Yee |
| Yaning Chen | Pierre Karly Jean Jeune | Oleg Makhnin | Shang Songhao | Abdullah Yilmaz |
| Lei Cheng | Haifeng Jia | Rabin Malla | Konstantinos Soulis | Yixing Yin |
| Lin Cheng | Dong Jiang | Deqiang Mao | Ryan Stewart | Pao-Shan Yu |
| Delson Chikobvu | Peng Jiang | Pau Marti | Ninghu Su | Feifei Yuan |
| Cybele Cholet | Shanhu Jiang | Pau Martí | Alex Sun | Hongbin Zhan |
| Chien-Ming Chou | Douglas Kane | Mario Martina | Peng Sun | Guanghui Zhang |
| Hatice Citakoglu | Sepideh Karimi | Shreedar Maskey | Yiqun Sun | Honebo Zhang |
| E.S. Cooper | Levant Kavvas | Arthur McGarity | Jang Hyun Sung | Ke Zhang |
| Barry Croke | Kenji Kawaike | Eleni Maria Michailidi | Anna Szczucinska | Linus Zhang |
| Simon Dadson | Ali Keshavarzi | Uta Moderow | Hossein Tabari | Qi Zhang |
| Ali Danandeh Mehr | Ingrid Keupers | Piotr Moniewski | Xuezhi Tan | Shanghong Zhang |
| Peng Deng | Kishanjit Khatua | Ramon Montero Mudarra | Zhenghong Tan | Yueguan Zhang |
| Ravinesh Deo | Giora Kidron | Mohammad Najafzadeh | Hansong Tang | Guangju Zhao |
| Giuliano Di Baldassarre | Kue Bum Kim | Fernando Nardi | Yin Tang | Jianshi Zhao |
| Mariaines Didato | Sungwon Kim | Jeff Neal | Rasiah Thayakaran | Min Zhao |
| Weili Duan | Tae-Woong Kim | Jun Niu | Mustafa Tombul | Wenzhi Zhao |
| Bruce Dudley | Ozgur Kisi | Markus Noack | Slavisa Trajkovic | Xuehua Zhao |
| Doris Düthmann | Michael Kizza | Umut Okkan | Hristos Tyralis | Mohammad Zounemat-Kermani |
| Anita Dyrrdal | Bjørn Kløve | Ilhan Özgen | J Vargas | Qiting Zuo |
| Andreas Efstratiadis | Krzysztof Kochanek | Juraj Parajka | David Velazques | |
| Ahmed El-Shafie | Marina Kolpakova | Marta Paris | Basappa Venkatesh |