| GEOMORPHIC REGIONS |
| 20. Catchment/ watershed/ basin hydrology |
| 21. Snow hydrology |
| 22. Glacier hydrology |
| 23. Mountain hydrology |
| 24. Hillslope hydrology |
| 25. Karst hydrology |
| 26. Hard-rock hydrology |
| 27. Alluvial-fan hydrology |
| 28. Floodplain hydrology |
| 29. Stream hydrology |
| 30. Lake hydrology |
| 31. Wetland hydrology |
| 32. Peatland hydrology |
| 33. Coastal/deltaic hydrology |
| 34. Estuarine hydrology |
| 35. Island hydrology |
| 36. Global hydrology |
| 37. Prairie-pothole hydrology |
|
| METHODOLOGIES |
| 38. Deterministic hydrology |
| 39. Stochastic hydrology |
| 39. Statistical hydrology |
| 40. Parametric hydrology |
| 41. Conceptual hydrology |
| 43. Analytical hydrology |
| 44. Numerical hydrology |
| 45. Theoretical hydrology |
| 46. Applied hydrology |
| 47. Experimental hydrology |
| 48. Scientific hydrology |
| 49. Engineering hydrology |
| 50. Computational hydrology |
| 51. Synthetic hydrology |
| 52. Kinematic hydrology |
| 53. Dynamic hydrology |
| 54. Physical hydrology |
| 55. Spatial hydrology |
| 56. Systems hydrology |
| 57. Field hydrology |
| 58. Operational hydrology |
| 59. Online hydrology |
| 60. Soft computing hydrology |
|
| TOPICAL |
| 61. Environmental hydrology |
| 62. Water-quality hydrology |
| 63. Contaminant hydrology |
| 64. Drainage hydrology |
| 65. Mining hydrology |
| 66. Reservoir hydrology |
| 67. Road/bridge hydrology |
| 68. Navigational hydrology |
| 69. Nuclear hydrology |
| 70. Military hydrology |
| 71. Economic hydrology |
| 72. Socioeconomic hydrology |
| 73. Historical hydrology |
| 74. Archaeological hydrology |
| 75. Medical hydrology |
| 76. Political hydrology |
| 77. Forensic hydrology |
| 78. Ecohydrology |
| 79. Geohydrology |
| 80. Paleohydrology |
| 81. Transboundary hydrology |
| 82. Space hydrology |
| 83. Microscale hydrology |
| 84. Mesoscale hydrology |
|
| RELATED FIELDS |
| 85. Hydrogeology |
| 86. Hydroecology |
| 87. Hydrometeorology |
| 88. Hydroclimatology |
| 89. Hydrosedimentology |
| 90. Hydroarchaeology |
| 91. Hydrochemistry |
| 92. Hydrobiology |
| 93. Hydrogeography |
| 94. Hydroinformatics |
| 95. Sediment-transport technology |
| 96. Fluvial geomorphology
| | 97. Deltaic geomorphology
| | 98. Potamology
| | 99. Water law |
|