Details:

Creators:
Papanicolaou, A.N. Thanos ; Elhakeem, Mohamed
Papanicolaou, A.N. Thanos ; Elhakeem, Mohamed Less -
Corporate Creators:
Iowa Institute of Hydraulic Research. Hydroscience & Engineering
Corporate Contributors:
Iowa. Highway Division ; Iowa. Highway Research Board ; Iowa. Dept. of Transportation
Iowa. Highway Division ; Iowa. Highway Research Board ; Iowa. Dept. of Transportation Less -
Subject/TRT Terms:
[+]
Banks (Waterways) Coast And River Protective Works Erosion Control Hydraulic Structures Hydraulic Structures--Iowa--Design And Construction Hydrologic Phenomena Riprap Streamflow Streamflow--Iowa
Publication/ Report Number:
IHRB Project TR-534
Resource Type:
Tech Report
Geographical Coverage:
Iowa
Edition:
Final report.
Abstract:
The main objective of this study was to evaluate the hydraulic performance of riprap spurs and weirs in controlling bank erosion at

the Southern part of the Raccoon River upstream U.S. Highway 169 Bridge utilizing the commercially available model FESWMS

and field monitoring. It was found based on a 2 year monitoring and numerical modeling that the design of structures was overall

successful, including their spacing and stability. The riprap material incorporated into the structures was directly and favorably

correlated to the flow transmission through the structure, or in other words, dictated the permeable nature of the structure. It was

found that the permeable dikes and weirs chosen in this study created less volume of scour in the vicinity of the structure toes and

thus have less risk comparatively to other impermeable structures to collapse. The fact that the structures permitted the

transmission of flow through them it allowed fine sand particles to fill in the gaps of the rock interstices and thus cement and better

stabilize the structures. During bank-full flows the maximum scour hole was recorded away from the structures toe and the scourhole

size was directly related to the protrusion angle of the structure to the flow. It was concluded that the proposed structure

inclination with respect to the main flow direction was appropriate since it provides maximum bank protection while creating the

largest volume of local scour away from the structure and towards the center of the channel. Furthermore, the lowest potential for

bank erosion also occurs with the present set-up design chosen by the IDOT. About 2 ft of new material was deposited in the area

located between the structures for the period extending from the construction day to May 2007. Surveys obtained by sonar and the

presence of vegetation indicate that new material has been added at the bank toes. Finally, the structures provided higher

variability in bed topography forming resting pools, creating flow shade on the leeward side of the structure, and separation of bed

substrate due to different flow conditions. Another notable environmental benefit to rock riprap weirs and dikes is the creation of

resting pools, especially in year 2007 (2nd year of the project). The magnitude of these benefits to aquatic habitat has been found in

the literature that is directly related to the induced scour-hole volume.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:353102d537a4c0690755272facdf9336c0db94eaaa8642773eb132daa0892ccd
Download URL:
https://rosap.ntl.bts.gov/view/dot/23456/dot_23456_DS1.pdf
File Type:

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