For example, a study showing that a certain technique reduces road surface erosion typically measures sediment yield by collecting runoff from the road prism. This reduced erosion from the road will inherently affect sediment input to nearby rivers and streams, although the reduced erosion was not necessarily measured within the waterways. The nearby rivers and streams did most likely benefit from the reduced erosion, but this can only be inferred. Such an association is based on common sense as well as scientific literature showing travel distances of eroded material. We can hypothesize, then, that reducing road surface erosion benefits water quality by reducing sediment input to nearby streams.
Forest management is directly related to economics.
For example, timber harvesting in itself can be an economically beneficial practice. For the timber industry, direct monetary benefits outweigh direct monetary costs. Unfortunately, the consequence of timber harvesting and exporting logs from the forest have a toll on the soils, water, and biota surrounding it. Environmental improvements, however, add a monetary cost to practices like timber harvest while the economic benefits of environmental improvement remain difficult to quantify. While water quality and timing changes can be seen from improved management, timber harvesting becomes less profitable due to the added cost of water quality remediation.