How to Find Surface Water
Streams, rivers, lakes, ponds, and springs are likely to be the easiest sources of water for you to find. However, out in the middle of the wilderness, determining the location of these water sources could be time consuming. As such, it's best to become familiar ahead of time with the signals that water is close by.
Understanding the terrain around you will help you recognize how water will flow from high ground to low ground. Rivers and streams are found in these drainage areas whereas lakes and ponds are found in the low lying areas.
Plants need water to survive. Where there is lush grass or abundant vegetation, there is likely a source of water. Deciduous trees also generally grow close to water.
People are not unique in their need for water. Animals seek it out to and the signs they leave behind can help lead you to water. For example, if two animal trails merge and become one, that is a good sign that there is water ahead. If you come across multiple animal droppings, you may be close to a gathering spot where animals have come to drink.
At dawn and dusk, birds often fly toward water. Try following these flight paths. Alternatively, during the day flocks of birds circle water so look for this signal too.
Like birds, insects often congregate where water is present.
Of course, not all water sources are created equal. By far the best are streams because the water is more likely to be safe when it is constantly moving. The faster the movement, the better your chances are. And it almost goes without saying, but avoid, if possible, areas of water that have an oily film or significant algae overgrowth.
Wilderness Survival by Gregory J. Davenport