- The erosive action of rivers and seas has immense influence on the appearance of the physical landscape. However, the creation of several important river and coastal features are not available in terrain creation software and systems. We have designed algorithms to easily create these features, namely (1) river meanders, (2) river deltas, (3) coastal cliffs, and (4) beaches. A terrain that does not have these features the looks unnatural. WaterWorld is a user-directed automatic terrain generation tool that we have designed. Similar to existing methods, it allows users to create mountains, canyons, rivers and seas. Its novelty is the inclusion of tools to create meanders, deltas, beaches and cliffs, to obtain a more realistic terrain..