An Ecological Assessment of the Louisiana Tensas River Basin Chapter 3 
Roads Along Streams 
Roads affect stream water in many ways and roads in 
close proximity to streams have the most potential for 
adverse effects on stream water quality. Figure 3.8 
shows road intersections with streams by sub-watershed 
in the Tensas River Basin. Since roads have an impervi¬ 
ous surface, and ditches are built to channel water off 
roads and into streams, the rate of water runoff is higher 
where there are more roads. Although large spills of 
polluting materials are rare and often quickly contained, 
small spills of petroleum products, antifreeze, and other 
vehicle-related chemicals happen every day on every 
mile of road in the region. These small spills eventually 
go somewhere, usually into streams. Road construction 
near streams is a temporary stress on water quality, but 
after construction, the roads remain, and routine mainte¬ 
nance can contribute to poorer water quality. For these 
and other reasons it is important to consider how the 
proximity of roads to streams might influence regional 
water quality. 
Forests in the Landscapes 
Forests are important elements of both natural and 
human-dominated landscapes. Forests provide many 
benefits including wood fiber, outdoor recreation, wildlife 
habitat, and regulation of some watershed hydrologic 
functions. Historic patterns of land use and development 
have created the present distribution of forests from what 
once was essentially all forest. There have also been 
changes in the plant and animal species which live in 
forested environments. In this section, the pattern of the 
existing forest cover is described as it affects various 
environmental values, particularly wildlife habitat. 
Percentage of Forest Cover 
Zone 
Kilometers 
Ha 
Ratio of Km/Ha 
2 
83.5 
5,601 
1.49 
3 
485.0 
45,387 
1.07 
4 
949.9 
92,471 
1.03 
5 
491.4 
61,742 
0.80 
6 
46.7 
11,126 
0.42 
7 
63.6 
7,345 
0.87 
8 
778.4 
79,713 
0.98 
9 
767.1 
72,212 
1.06 
Total 
3,666.0 
375,807 
0.98 (Avg) 
Figure 3.7 
Roads in the Tensas River Basin. Source: US Census TIGER. 
At one time, nearly all parts of the Tensas River Basin 
were forested. Today, the amount of remaining forests 
helps to indicate the probable condition of streams within 
each watershed. The proportion of watershed covered 
by forest is indicative, but not conclusive, of stream 
conditions because the specific types of non-forest land 
cover (such as urban or crop) are also important. 
