"One of the most beautiful canyons in Utah, Logan Canyon serves as a winding, narrow, scenic corridor connecting the city of Logan with the beaches of Bear Lake, 40 miles to the northeast, combining colorful foliage with high statuesque limestone formations on either side." (Abbey, 1974)
The Utah Department of Wildlife Resources has reported that "the natural beauty of Logan Canyon, along with limited developments by man helps make Logan River (which passes through the canyon) a very popular fishing stream" and "one of the most important stream fisheries in Northern Utah".
"Few man-made features exist to interrupt the almost total intactness (consistency) of the natural landscape. U.S. Highway 89 is aligned with the topography so unity (compatibility) also exists. Managed as a scenic highway by the United States Forest Service...policy states that a road such as this should be assigned a sensitivity level 1, which signifies the highest public level of concern for scenic quality." (FEIS Highway 89 Logan Canyon)
Highway 89 through Logan Canyon was originally constructed in the 1930s. It provides a transportation link between western Wyoming, southeastern Idaho, and northern Utah. Much of the canyon lies within the Wasatch-Cache National Forest, and besides connecting Cache Valley with Bear Lake, the canyon provides many recreational opportunities. The first 9 miles of the highway from Logan to Right Fork were widened in the 1960s. The 28 miles from Right Fork to Bear Lake has not been widened and has been the focus of much controversy the past few years. The roadway is narrow with relatively steep slopes that drop away from the highway. There are also sharp curves throughout the canyon, areas where sight distance is minimal, and very few stretches of the highway providing opportunities to pass. A number of bridges are narrow as well.
Logan Canyon, once considered for national park designation, is well known in Utah for its alluring beauty. Highway 89 through the canyon has, in fact, been set apart as a scenic byway. The rich canyon ecosystem is not only pleasing to man, it is home to many forms of fish and wildlife. The concern for both the scenic quality and the natural environment has sparked significant public opposition to the widening and straightening of the highway from Right Fork to Bear Lake. This opposition stems from the fact that current studies for improvement of the highway have determined that the canyon will suffer damages due to construction on the road, especially to riparian areas along Logan River. However, the Utah Department of Transportation (UDOT) has determined that major rehabilitation of the pavement, as well as the replacement of the five major bridges in the canyon, is necessary. None of the bridges meet recommended guidelines that all bridges have adequate strength and a width consisting of the travelway (that part of the road intended for use by moving vehicles) plus two feet of clearance on either side (Draft Environmental Impact Statement, 1990).
Burnt Bridge
The purpose of the construction project is to improve traffic flow on the highway, resulting in increased traffic-carrying capacity. Many people desire improved driving conditions and traffic flow through the canyon. There is concern by the public and some grassroots organizations that the improvements not degrade the canyon environment, however. The Final Environmental Impact Statement (1993) and the Record of Decision Document for Highway 89 (1995) report that "there will be either no or only minor effects on...the resources and characteristics affecting the scenic, historic, recreation, wildlife and fish, cultural and other values associated with the river and river corridor (riparian areas)." (Record of Decision, 1995)
Our objective for this project is to use GIS in examining the proposed changes on Highway 89 and how they will affect the river, riparian areas, geology and vegetation in Logan Canyon. GIS enables us to visualize how the canyon will be impacted before the bulldozers roll in.
Methodology
Data:
Coverages: Water courses- Utah State Geographic Information Database(SGID) Contour Lines- SGID GAP Vegetation Analysis- SGID Roads- /auto/cache Database Waterbodies- /auto/cache Database Imagery: Cache TM Orthophoto Maps: Cache 1:100 000 Quadrangle Other Resources: -Draft Environmental Impact Statement for U.S. Highway 89 Through Logan Canyon- Utah Department of Transportation (UDOT) -Final Environmental Impact Statement for U.S. Highway 89 Through Logan Canyon- UDOT -Record of Decision- UDOT
Processes:
Clip: Once the data had been collected, the first step was to clip the coverages so that we were working with the Logan Canyon area only. The coverages were over the entire county, so we needed to get rid of the unnecessary information. To get the canyon region, we had to make a clip coverage that could be used to clip the other layers (roads, vegetation, water courses, and contour lines). We used the Cache 1:100 000 Quadrangle to make our clip coverage, since it was the same scale as the layers. We digitized our area of interest from the Cache quad, and had to convert it to UTM units instead of latitude/longitude units. Once it was digitized, we could then use the digitized layer as a model from which to clip the others. Buffer: The next step was to buffer Highway 89 on the road coverage. We buffered the road ___ feet, which is approximately how much wider the road would be after construction. By buffering, we were able to examine the area surrounding the road that would be impacted once it was widened. Overlay:Once the coverages were clipped and the highway buffered, the next step was to overlay the road layer with the vegetation, water courses and elevation layers. The buffer showed the extent to which the various coverages were affected. We compared our results to the data received from the Utah Department of Transportation to see how accurate they were. Photographs were taken of the different locations in the canyon where extensive alterations would need to be made in order for the proposed construction to happen.
Results
Once the technical "stuff" was completed, we analyzed our results. Although the Utah Department of Transportation has stated in the Record of Decision Document that impact on riparian areas will be minimal because of road construction, our project shows that some impact will be inevitable. Because of the size of the canyon and the small scale of the coverages, we will provide various close ups of areas that will be severely altered where damage to riparian areas will occur.
The following is our area of study showing the beginning of the proposed construction at Right Hand Fork and extending to the Tony Grove area. The entire area of UDOT's project would continue to Garden City. However, we have chosen our study area because the potential damage to riparian areas in this section appeared to be most threatening.
Study Area
To be able to visualize the impact to riparian areas more clearly, we decided to divide our study area into sections. The first section extends from Right Hand Fork to the Logan Cave area. In this section, substantial impacts will occur. The curves at mileposts 384 and 387 may be flattened and vegetation removal and river bank modification will be required upon replacement of Burnt Bridge.
Section 1
Because we have used the Veg100h coverage from the SGID as a base for our study area, vegetation is grouped and classified by the following colors:
-Aspen, Oak, Maple
-Sagebrush, Grassland, Mountain Shrub
-Spruce, Fir, Juniper, Pinyon
As shown here, all types of the vegetation listed above will be affected on this stretch of the road. The buffered road, (the fattened red line) shows the path of the proposed road widening and the approximate extent of the affected areas.
To zoom in on areas of potentially heavy impact to riparian areas and the mountain side surrounding the highway, we will present specialized maps that contrast the existing road (yellow) with the proposed new alignment (orange) and outline the area that will be affected by construction (red). Of course, the river will be shown in blue along with its riparian areas represented by green. This first map of this type is the area around the southern end of Burnt Bridge and the bridge itself.
Burnt Bridge
The second section begins at Logan Cave and extends to the Ricks Springs area. This area will be impacted much more so than the first section. Among the many proposed changes are the straightening of six curves (all of which will require the removal of rock material and creating new cuts), the replacement of Lower and Upper Twin Bridges, and the elevation of the roadway above Ricks Springs to eliminate flooding.
Section 2
The map shows that the highway is surrounded by a large amount of vegetation including aspen, oak, and spruce. In most cases, the vegetation borders the road and would require removal for widening to occur. The river also runs parallel the highway in much of this section. The activities associated with the widening of the road would increase erosion resulting in increased turbidity as well as disturbance of riparian habitat. These impacts would be greatest in this section where the highway is close to the river.
Lower Twin Bridge
The replacement of Lower Twin Bridge with a new bridge will require the removal of the mountain side for the proposed bridge that would clear-span the river. The map below shows that the new bridge would be upstream of the present bridge and the red lines show the amount of rock that would need to be removed.
Upper Twin Bridge would be replaced with a 38-foot wide bridge immediately downstream from the present bridge. Once again, the map on the right shows how the proposed roadway will differ from the existing and the amount of rock that would need to be removed for the new highway to be possible.
Lower Twin Bridge Upper Twin Bridge
The third and final section of our study area begins at Ricks Springs and ends at Tony Grove. This section consists of a much straighter roadway than the first two sections. Proposed changes are minimal in this area. Some widening of the road would occur where a passing lane would be constucted up to the Tony Grove intersection, as well as left and right turn lanes into Tony Grove. Red Banks Bridge, located just north of the Tony Grove intersection, would be replaced, but on its original alignment with minimal effects on the river and riparian areas.
Section 3
The map above shows that this section of the highway is bordered by oak, aspen and maple trees. The widening of the road would again require the removal of vegetation. Although some vegetation would have to be removed, compromises have been made so that impacts on the aquatic, riparian and visual environments would be as minimal as possible.
Conclusion
People in Cache and Rich Counties are anxious for improved traffic flow and safer driving conditions through Logan Canyon. However, there is also a large percentage of people from both counties who view the canyon as more of a destination rather than merely a way to get from point A to point B. The scenic and recreational value of the canyon has made it an overwhelmingly popular site over the years and now, the very qualities that draw people to the canyon are in jeopardy of being permanently damaged. The controversy continues between whether a wider and straighter road is really a safer road and if it is worth the price of the impact on the environment. Our research has allowed us to see and understand both sides. We know that construction is necessary, but as our presentation shows, there will be considerable impact on riparian areas along the Logan River, with other significant impact occuring through vegetation removal and roadside cuts. Through GIS, we have been able visualize and understand that when man alters his environment for his own benefit, the land will always suffer. The canyon will be changed forever if the proposed construction is finalized, therefore, it is crucial that we can see the results of our plans before the deed is done and irreversible.