Peter Wilcock's Web Page
I've retired from USU. I continue to work on some legacy projects, with a focus on making more widely accessible some ideas and models that I think are useful in the general areas of sediment transport, fluvial geomorphology, and stream restoration. This web page will serve as the place to organize these contributions. My immediate project is to make some brief videos explaining the principles of mixed-size sediment transport and the application of those principles to river chanel assessment and design. At the heart of the applications is the inverse application of the Wilcock & Crowe transport model. The most promising application - not quite complete - is inverse application of W&C2003 to determine the slope of a graded river (a channel able to transport all of its supplied sediment over all its flows). This is a geomorphic topic with a century of history. The successful computation of a graded slope allows us to design channels without having to first specify a "dominant" discharge. I think this is a big deal and I will be working to finalize and polish the method in the next year or two.
The one-week short course Sediment Transport in Stream Assessment and Design will be offered in Logan UT August 4-8 2025.
Here is a link to the 2024 course and the associated course materials
1. These videos are not meant to provide a general course in open channel hydraulics and sediment transport. I have not tried to bring in all ideas and contributions. Rather, the videos focus on things I've figured out over the years and then worked to make useful and accessible. The videos are unedited with a charming lack of production values and zero attention to modern pedagogy. If you want it -- it's here. If you don't want it -- nothing to see here.
2. PDFs are provided of the slides used in the videos. If there is a spreadsheet involved, it can be downloaded as well. I also make available journal papers where available and relevant.
3. The material presented here contains general concepts. Application to real places with real consequences and real lawyers will require considerable scientific and engineering judgment and site-specific knowledge that are explicitly beyond any of the material here. Use at your own risk and under your own responsibility.
Lectures and slides and spreadsheets and papers
Mixed-size transport of gravel and sand-gravel mixtures
| Topic | Description | Slides | Video | Documents |
|---|---|---|---|---|
| Why you need a surface-based approach to sediment transport | The transport rate of a mixed-size sediment depends on the size of the grains immediately available for transport on the bed surface. Numerous processes drive sorting of the bed surface, including kinetic sieving and differences in mobility among different sizes in a mixture. This presentation illustrates the need for a surface-based approach by considering the question of whether a coarsened surface layer (armor) persists over the range of flows in natural streams and by contrasting the behavior of flumes in which sediment is recirculated and sediment is fed and . | slides | on YouTube | Wilcock and DeTemple (2005) |
| Overview of Wilcock & Crowe Transport Model | The Wilcock-Crowe transport model was developed from a set of data giving paired observations of stress, transport rate, and the grain size of both the transport and the bed surface. This presentation presents those data and explains the particular components of the W&C2003 model and the general concepts behind the similarity collapse used to develop W&C2003 and other transport models. It also emphasizes that W&C2003 (and most other transport models) are unit process models and must be applied with care at larger scale in often highly variable enivronments. Also: how to calibrate W&C to field transport data. | slides | on YouTube | Wilcock and Crowe (2003) |
| Overview of iSURF | Wilcock and Crowe 2003 is invertable! That means you can specify a sediment transport rate and grain size as the sediment supply to a reach and the inverse model will give you the bed surface grain size and the shear stress producing that transport. If you also specify water discharge, elementary hydraulics will give you flow velocity, depth, and channel slope. With a calculated slope for a given flow and sediment supply, we are off to the races. iSURF solves W&C in forward and inverse forms and contains two applications - one for channel design and one for a state diagram relating transport, flow, and slope. | slides | on YouTube | iSURF_Public.xlsm iSurf_Test_Input.xlsx |
Connecting sediment transport and simple channels
| Topic | Description | Slides | Video | Documents |
|---|---|---|---|---|
| Quantifying Lane's Balance |
Lane's balance is evocative and intuitive. It lays out the four essential variables of a sediment balance: water discharge, transport rate, grain size, and channel slope. Lane's balance is also indeterminate and non-quantitative. We can make it explicit using four fundamenntal relations for transport rate, continuity, momentum, and flow resistance. The most relevant interpretation of the four variables is that sediment transport rate and grain size represent that of the sediment supply, leaving slope as the dependent variable, addressing the question: what slope is needed to transport the supplied sediment with the available flow? |
on the way | on the way | working on a new spreadsheet Schmidt and WIlcock (2008) |
| Threshold Channnels | on the way | on the way | on the way | |
| Alluvial Channels | on the way | on the way | on the way | |
| Over-Capacity Threshold Channels | A full explanation and demonstration of OCT: coming soon! For now, I offer a video and spreadsheet for a case in Utah. |
Provo R Delta Example | Provo R Delta Example | iSURF_ProvoDelta.xlsm OCT_ProvoDelta.xlsx |
| Beyond Bankfull! | Inverse solution of Wilcock & Crowe 2003 allows us to determine the slope needed to transport a specified sediment supply at a specified discharge. But we can also find the slope needed to transport ALL of the sediment supply over the full range of discharge. This is the GRADED slope of Gilbert, Mackin, etc. This is important! We no longer have to pick a single dominant discharge to assess or design a channel. I call this BEYOND BANKFULL (tip of the hat to K. Prestegaard). We are still working on a bomb-proof solution to the problem (we know the solution exists and have a working code, but the numerics behind an inverse solution over a range of flows are pretty intense). In the meantime, you can enjoy a short paper on it. |
|
Library
"The Primer"
Wilcock, Peter; Pitlick, John; Cui, Yantao. 2009. Sediment transport primer:
estimating bed-material transport in gravel-bed rivers. Gen. Tech. Rep.
RMRS-GTR-226. Fort Collins, CO: U.S. Department of Agriculture, Forest Service,
Rocky Mountain Research Station. 78 p.
This primer accompanies software developed to calculate sediment transport rate in gravel-bed rivers. Such programs facilitate calculation and can reduce some errors, but cannot ensure that calculations are accurate or relevant. This primer was written to help the software user define relevant and tractable problems, select appropriate input, and interpret and apply the results in a useful and reliable fashion. It presents general concepts, develops the fundamentals of transport modeling, and examines sources of error. It introduces the data needed and evaluates different options based on the available data. Advanced expertise is not required.
Although the focus of the primer is on making estimates of transport rate, it also provides suitable background for those interested in learning about basic mechanisms of flow and transport of mixed-size sediment in gravel-bed rivers.
Schmidt and WIlcock (2008)
Wilcock and Crowe (2003)
Wilcock and DeTemple (2005)
Wilcock 2023 FISC Beyond Bankfull
Brief Bio
