Introductory technical guidance for civil engineers, marine engineers, and other professional engineers and planners interested in coastal estuaries. Here is what is discussed: 1 DEFINITION, 2. CLASSIFICATION OF ESTUARIES, 3. TIDES AND OTHER LONG WAVES, 4. WINDS AND WIND-GENERATED WAVES, 5. FRESHWATER INFLOW, 6. CHANGES IN SEA LEVEL, 7. SUMMARY.