Реферат: Forest Roads And Their Effect On Water

Quality Essay, Research Paper

Forest Roads And Their Effect On Water Quality

Roads are often necessary to perform certain tasks in the forests. When roads

are made, they often pose the problem of erosion, and damage to nearby

water sources. The two articles I read on this topic were both from the

August 1999 issue of the Journal of Forestry. Both discuss the different

techniques and methods for trying to limit the amount of silt that contaminates

roads due to disturbance.

The first article, ?What We Know- and don?t know- about Water Quality at

Stream Crossings,? discusses the different methods used to cross streams, and

which method causes the most long term, and short term damage to water

supplies. Forest road crossings have become a concern, because they are

places where disturbance, and water run off cause silt to get into streams and

water sources. The three main methods discussed in detail in this article for

crossing a stream are: fording, using culverts, and either a temporary or

permanent bridge.

The most impactive method, according to this article was the practice of river

fording. This method causes inordinate amounts of downstream silt because

every time a vehicle fords a crossing, some contaminates are added to the

water, in addition to the silt on the stream bottom that is disturbed and

washed downstream.

In terms of impact, putting culverts in a stream causes about the same initial

impact, as creating a ford, but subsequent impact is less, because cars are no

longer forced to drive through the water. Culverts can cause problems too,

because of the potential for them to plug up, causing washout, and silt

deposits.

The third, and most preferable method, according to this article, is the

construction of bridges (either permanent, or temporary).

By doing this, virtually all contaminants remain free of stream water, because

the actual stream does not have to be disturbed.

The second article summarized, ?Forest Roads: Where Soil and Water Don?t

Mix? shared similar opinions on most points. This Article brought up

several additional and perhaps more idealistic points. According to this

article, most resource damage in an area is done in the first two years after a

road is constructed. During construction, this article points out that it is wise

to limit the number of stream crossings to a minimum.

When crossings are necessary, though, this article suggested the use of

sediment ponds, and not allowing water to build up it?s mass and momentum.

When momentum is built up, water will erode more of the earth, causing

more sediment build- up in streams.

Personally, I did not really realize that there was even an issue of too much

sediment in streams due to forest roads, and stream crossings. It was

amazing to learn of all the dangers to the environment caused by yet another

type of pollution. This problem might not cause the immediate and drasti

problems that other environmental issues might, but eventually, because of

our interactions with the forest and it?s waterways, we might alter the

ecosystems in ways that we can?t even fathom.

1. Egan, Andrew F. ?Forest Roads: Where Soil and Water Don?t Mix.?

Journal of Forestry. 97. August 1999. 18-21.

2. Taylor, Steven E., Et Al. ?What We Know- and Don?t Know- about Water

Quality at Stream Crossing.? Journal of Forestry.97. August 1999. 12-16.