 Everywhere you look in this forest, you see the signs of an ecosystem imbalance from the hardiness of the native plants and wildlife to the undisturbed soil and clear running streams. There are roads here too. They've also become an integral part of the forest. Their condition reflects not only the technical know-how of the people who build and maintain them, but also a keen awareness of the surrounding environment and a concern for the forest's future and our own. We're in the Coronado National Forest east of Tucson, Arizona on a road that runs from the turnoff back there to a little campground about a mile further down. In a way this stretch of road is typical of the roads throughout our national forest system. Not that this location is necessarily typical. We also have roads in national forests that are classified as rain forests or even high desert. What's typical about this road is that it's unpaved, it serves multiple needs, and it interacts profoundly with its natural surroundings. Wear and tear from traffic and weather make it necessary to repair these roads and their drainage systems periodically, but advances in science and technology have dramatically improved our understanding of how to go about it in ways that sustain both the road system and the surrounding environment. After all, national forests are among our most vital assets, and we need to preserve them for generations to come. Forest service roads hold a unique place both in our country's transportation system and in the natural environment. They provide ready access to nature for the traveling public and facilitate the management of natural resources. When any road falls into disrepair and remains untended, it can compromise the safety of drivers and the health of neighboring ecosystems. When that road runs through the complex environment of forests, environmental considerations become especially important. To understand how a road interacts with a forest, we first need to look at what happens between natural elements when there aren't any roads. It's an eons old story that begins with water and soil. Each forest has a number of watersheds that collect water from rain and melting ice and snow or from rainfall alone. The water flows over and through the forest floor as surface flow and groundwater. At first, it moves slowly downslope, dispersing over a wide area. Forceful buildup or concentration won't normally occur until the water encounters and enters small streams. From smaller streams, it travels to larger ones, and finally into the watershed outlet, usually a river. A river's water represents the accumulation of groundwater, surface flow, and stream flow. When you add a road to this picture, you risk interfering with the natural process. Roads can intercept and divert natural diffuse water flow, concentrating it randomly and prematurely. Here, the road has diverted water from its natural drainage path. It no longer descends downslope in a normal dispersed pattern. Instead, it's become concentrated and in extreme conditions may even become displaced, overloading one watershed or sub-watershed, while depleting another. Another possible consequence of a change in normal water flow patterns is for ditches and culverts to concentrate water runoff so that it flows down to small channels, streams, and rivers too quickly, overburdening them with a higher than normal water accumulation, taking place in a shorter than normal time period, increasing the effects of peak flow. Like wind, rain, and vehicle or equipment traffic, water concentration can begin the process of erosion, separating soil particles from the ground, and allowing them to be transported until they settle out in other parts of the forest, including lakes and streams. Once in the stream, the sediment changes the aquatic and adjacent riparian ecosystems. It covers up and fills in spawning beds, suffocating fish eggs, insect larvae, and other organisms. The soil also clouds the water, making it harder for the streams inhabitants to locate their diminishing food supply. Those that do survive often suffer the abrasive effects of the soil particles on their sensitive gill tissues, slowly but surely as the sediment settles out, the stream becomes shallower and warmer, further lowering survival rates of eggs and fry. The raising of a stream bed also causes the stream to become wider to accommodate the normal volume of water. This results in erosion of overhangs, the shady interlocking masses of vegetation that normally provide a sanctuary for aquatic life to hide, rest and feed. As usual in an ecosystem, local impacts don't remain local. As small creeks become sediment laden and warm up, they in turn warm and otherwise alter larger ones downstream. Neighboring human communities aren't exempt either. Sediment increases the cost of purifying drinking water and fills in reservoirs and canals. It can even damage turbine generators in hydroelectric facilities. Some effects are harder to measure than others. How can you calculate the cost of losing a choice fishing hole? Or a favorite hiking trail or campsite? Of course questions like that are impossible to answer, but there's a related question those of us who maintain forest roads ask every day. How can we have the roads we need and safeguard the environment? The answer can be found in the earlier question of where the water would go if the road didn't exist. Do everything you can to emulate the way nature moves water, and you minimize disturbance to both the road and its natural surroundings. The key to putting that principle into practice is dispersing rather than concentrating road-diverted water flow. That means using the most effective measures available for controlling the volume and velocity of water. The first step is to make sure the traffic bearing portion of the road, also known as the traveled way, has and maintains a properly defined shape. Water should move off that surface efficiently so that it doesn't degrade the road. Whenever possible the water should be released into the forest in a well dispersed pattern that doesn't disturb surrounding soil. In maintaining drainage structures like this lead-out ditch, it's important to imitate nature's way of protecting exposed areas. Vegetative materials like these reduce the speed and to a lesser degree the concentration of the water. So do ditch dams and other barriers. The flow can also be channeled into flat vegetated areas of forest floor, allowing the water to soak into the ground, leaving the sediment behind. One of our primary objectives when dealing with road drainage is to reduce or eliminate fine sediment from entering the stream channel. And a particularly effective way to do that is to provide a buffer strip between the road and the stream. And that buffer strip can consist of grass or something considerably more dense like brush. What that does is it allows the velocity to drop enough that the fine sediment settles out before entering the stream channel. Settling ponds are another effective water control measure. They do just what their name implies. Interrupting and slowing down the water flow so that sediment can settle out rather than continue its journey to other parts of the forest. Of course, these man-made systems are only as good as their upkeep, but with regular care they function effectively as part of the forest defense against erosion and sedimentation caused by concentrated water flow. Of course, as we've seen, too little water is the other side of the problem when a road diverts water from its normal flow path and unnaturally concentrates it. The flow may erode the ground so deep that it's below the natural water table. This causes the water level to drop, killing shallow-rooted grasses and other vegetation. That can upset the natural balance between and within the forest's plant and animal species, ultimately leading to even more erosion and related changes to the forest. For example, if shallow-rooted grasses and other ground cover plants die off, they're no longer able to help hold the soil together and to slow and disperse concentrated water. When rain does come, it falls on soil that's much more susceptible to erosion. Of course, no matter how skillfully you maintain the roads, it just isn't possible to stop all erosion, but it is possible to minimize or modify even in extreme conditions. Here in the Sonoran Desert of the Coronado National Forest in southern Arizona, there's less than 12 inches of rainfall a year. Conducting necessary repairs on these roadways can seriously reduce their surface cohesiveness, if done without proper moisture content. Left untreated, the soil could soon be carried away by the wind and by whatever precipitation does occur. So in a place like this, during operations like blading, it's especially important to keep the proper moisture content in the road surface to allow proper shaping. This may mean mechanically spraying the road surface with water or scheduling road work soon after a rainfall. In any location, but especially a drive-in like this, compacting the road immediately following blading operations is essential to improving the soil's cohesiveness. In some situations, soil stabilizing additives may also be needed. Here, as in all forest service road maintenance, the new and improved rule of thumb is disturb the soil only when absolutely necessary, and when it is necessary, use a light touch. Does this roadside ditch need clearing and reshaping? Only if it's sending water back onto the road or otherwise functioning improperly. Experience and research have taught us that cleaner and clearer isn't always better when it comes to protecting forest soil. In fact, these rocks and plants are helping to slow the flow of water through the ditch and hold the soil together. In light of modern maintenance policies and practices, the presence of a road in a forest doesn't have to signal the presence of excessive erosion and its consequences, from stream sedimentation to possible slope failure. Peaceful coexistence between a road system and an ecosystem is nothing to take for granted. It demands a great deal of planning, care and skill, but it can be achieved. And the stakes couldn't be much higher, and surely the effort is worthwhile. National forest roads aren't just a means of accessing and managing resources, or getting from one place to another by way of the scenic route. Their condition directly impacts the health and longevity of a living treasure whose importance we're just beginning to fully understand. Whether or not forests like this one continue to thrive and prosper depends largely on how we do our jobs. For the men and women who work hands-on to maintain unpaved secondary roads, the task couldn't be more important or rewarding to truly make a difference in the natural world by helping to preserve and sustain our national heritage for generations to come.