Network techniques differ from other methods in that they allow for identification and tracing of the chain of effects that is expected to result from a proposed activity. Networks are based on the recognition that a series of effects, and not just one, may be triggered by an action and that those effects may well trigger additional effects, and so on. Networks, then, incorporate primary, secondary and tertiary effects. Properly constructed, they can also include cumulative effects.

The example that follows identifies interrelationships between the casual factors of dredging operations and the impacted environmental components. This is a useful method because it is comprehensive and indicative of the actual situation. The example depicts the areas affected; it does not depict the magnitude or significance of the effects. These can, in fact, be incorporated into the network, and absolute and relative changes can be traced through the system, as depicted.

Networks accomplish much more than other methods, but at a price. They are, of necessity, much more complex than other methods and therefore have much greater data requirements. Indeed, to trace actual effects through a network and to incorporate cumulative effects into the process demands large amounts of data and the consideration of numerous "if/then" scenarios. Data must also be accurate and reasonably detailed if they are to be useful throughout the network.

The associated costs with such an effort are high and may well be justified in a large project. In the end, even if measured actual effects can be traced, the significance of effects is not as readily incorporated into the analysis.

In order to be able to trace effects through a system, it is necessary to develop a network for each type of activity and perhaps the different environmental settings. There are difficulties associated with ensuring that all interactions are included, but these can be overcome by outside review of the network. The complexities depicted in a network are representative of the complexities of the situation being represented and that is a major advantage of this method. On the other hand, the same complexities may limit the utility of networks for other than very large projects where such detail and complexity is required, to sort through the relationships.