Facilitating Upstream Fish Passage
Our constructed infrastructure of roads and dams provides untold benefits for society at large by providing transportation access to all corners of the country and by providing water for irrigation and municipal use. Early design standards for these facilities, however, did not consider the ability of fish to move freely upstream and downstream through culverts underneath roadways and past small diversion dams on rivers. Fish species can become endangered when their habitats shrink to ever smaller reaches of streams. Research into x areas is currently being conducted: (1) design of culverts for upstream fish passage (field and laboratory work); (2) modification of small diversion dams for fish passage; and (3) stream alteration to improve spawning and rearing habitat for endangered Utah fishes. Research results will produce tools designers can use to better facilitate fish passage at these structures.
Dr. Rollin H. Hotchkiss
Dr. Russell Rader (Department of Biology)
Dr. Mark Belk (Department of Biology)
Managing Reservoir Sedimentation
Thousands of dams worldwide are nearing the limit of their design lives as upstream reservoirs fill with deposited sediment. In order to continue to enjoy the benefits from these projects, the means for managing sediment in an economical and environmentally beneficial way must be developed. Current research in this area has two goals. The first is to develop a predictive relationship for smaller Utah reservoirs that can be used to determine if a detailed reservoir sedimentation study is needed. The relationship will be developed using data from actual reservoirs and watersheds in Utah. The second is to better understand how to design and operate dams in different climates to encourage their sustainable use for generations, not just decades. A case study in a hurricane-dominated climate will be used to illustrate the design and operation guidelines.
Dr. Rollin H. Hotchkiss
Dr. E. James Nelson
Dr. Rollin Hotchkiss's Graduate Students Research
Provo River Decree
I am currently conducting research on a decree known as the Provo River Decree that has had a significant impact on water law in the Provo area. In 1914, the Provo River Decree allocated all of the available water in the Provo River to individual water users. These users were primarily irrigation companies that distributed water to farmers for their crops during the summer. The water rights established in that decree are still in effect today. However, much has changed in the Provo River Basin; the flow in the Provo River has changed due to the construction of two upstream reservoirs and several diversions, and the water use has changed significantly as farmland is replaced by urban development.
My thesis will consider whether Provo River Decree is able to adapt to these changing situations, and if not, what water users can do to best use their allocated rights. I am working directly with the Timpanogos Irrigation Company, of which BYU is a primary shareholder. A significant portion of BYU-owned land is irrigated through the Timpanogos Canal (see image). The water right for the canal dates back to the Provo River Decree and was originally allocated for cropland, although it is now being used almost exclusively to irrigate landscaped areas.
UDOT Stream Restoration Study
The Utah Department of Transportation (UDOT) has asked me to determine if stream restoration structures can be used to prevent scour in the vicinity of bridges and major highways. The stream restoration structures are small structures placed in a stream that direct flows away from the stream banks. Directing flows away from stream banks keeps erosion from happing on the banks. As a result, the scour and erosion occurs in the center of the channel and creates great habitats for fish. These structures are typically built out of rocks and root-wads. These materials are more natural looking and are also more fish friendly.
An extensive study is being performed for the stream restoration structures developed by Dave Rosgen. He has developed structures that redirect flows and erosion away from stream banks and towards the channel center; Cross-Vanes, J-Hooks and W-Weirs. These structures work well for fish habitats. However, their reliability is questionable for larger flood events and even more so near bridges and highways. Many have eventually failed in the past when faced with larger than 2 to 5 year flow. A study is being done for UDOT to determine if there is a way to upsize the stream restoration structures to perform according to the UDOT specifications while also being natural looking and fish friendly.
Soldier Creek Restoration Project
Our master’s project consists of restoring the function and diversity of a stretch of Soldier Creek in Spanish Fork Canyon. Over the past several decades the river has been straightened and deepened due to the construction of the Rio Grande railroad and Highway 6. Further degradation by cattle grazing has caused instability of the river banks, leading to large amounts of erosion. The high amounts of erosion, along with the increased water velocities and shear stresses due to straightening the river channel, have made it difficult for many aquatic species to inhabit the river.
In connection with the land owner and the Division of Wildlife in Utah, our project has three primary goals: 1) Improve fish habitat, 2) Construct habitat ponds for the endangered Columbia Spotted Frog, and 3) Design and build a dependable water diversion. Some of the major steps in accomplishing our goals were to take a detailed GPS survey of the area, create an HEC-RAS model, take fish and macroinvertebrate samples, design the frog ponds and diversion structure in AutoCAD, and use ArcGIS to map the locations of eroding banks within the project site. Future work to be accomplished within the next year involves submitting the required state and federal river restoration permits so that we can begin implementing our restoration design and measuring the amount of sediment that is carried by the river using sediment traps.
Jeremy Payne and Jared Erickson
Scour Hole Development
Image courtesy of Utah Department of Transportation
Image URL: http://blog.udot.utah.gov/wp-content/uploads/2012/05/Scour-at-Montezuma-Creek.jpg
A major issue in channel design and management is scour hole development in channels in critical areas. The largest cause of this is due in part to the stream discharge in the channel, but it is also affected by channel geometry. Development of scour holes has become a key issue in recent years as land has become more industrialized. Following a change in land use, a change in discharge will also occur, which can thereby affect the equilibrium state of a stream.
The purpose of this work is to develop an equation that will help predict where scour holes develop in a channel and subsequently their depth as well. Using the Reynolds Transport Theorem, in addition to St. Venant Equations, a second-order equation was developed that achieves this goal. By inserting the channel width, slope, and a distance from an established datum, the output provides the user with the channel depth at that location. The application of this equation will provide users with information on locations of scour holes, depth of scour, and subsequently information on channel degradation. Specifically, this can be applied to bridge abutments, culverts, stream restoration, and other stream degradation analyses.
Economics of Reservoir Sedimentation and Sustainability
The way in which dams and reservoirs have been designed and financed in the past has resulted in resource depletion and adverse environmental impacts. The principal mindset has been to garner as many economic benefits as possible for the least amount of initial investment. As a result, dams and reservoirs have repeatedly been built with no, or inadequate, sediment control. This has caused many reservoirs to fill with sediment within a predetermined lifespan, effectively reducing the number of suitable spots for additional dams, while also creating upstream and downstream damages due to sedimentation deposition and scour, respectively.
Designing a dam is not similar to designing a highway or building, and as such should be treated differently. In order to develop a sustainable design and an adequate financial plan, we must alter our mindset of dams and reservoirs as assets with a preset lifespan, as well as understand the costs, benefits, and implications of implementing such a change. These remarkable structures are, and will continue to be, vital for the economics of any generation.
Figure 1: Current benefit-cost ratio approach
Figure 2: Dam retirement option
Figure 3: Retrofit dam with sedimentation management
Figure 4: Sedimentation management as initial investment