uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Erosion och sedimentation i jordbruksdiken modellerade med HEC-RAS
2011 (Swedish)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Seepage of phosphorus from cultivated fields has been the focus of much attention from researchers

in recent years and is seen as a contributing factor to the eutrophication of the Baltic

Sea. Much of the transported phosphorus arrives as particle-bound phosphorus, attached to the

small particles of clay. Sediment transports in agricultural ditches are therefore an important

component in the process of phosphorus seepage. The purpose of the study was to examine

the model parameters that influence erosion of clay particles and to determine if the modeling

tool HEC-RAS is useful for modeling of erosion and sedimentation in agricultural ditches.

The work was carried out by constructing a ditch in HEC-RAS in order to simulate the test

area Hestadbäcken. Measurements of

the ditch’s geometry and soil sampling were conducted

to simulate the ditch features. The simulation results were compared with existing data for

sediment transports within the runoff area.

The data that existed for calibration and establishment of boundary conditions was not sufficiently

extensive or precise to validate the

model’s credibility. Due to lack of sediment and

erosion data, suspended material was mainly used as a measure of the amount of sediment

moving in the ditch. It turned out that the modeling results give a deviation from the calibration

data for large transports of suspended materials. It cannot be determined if this is a shortcoming

of the modeling tool since the calibration data is not sufficiently reliable. The parameter

that has the greatest impact on the result is Mannings roughness coefficient,

n. It is also the

parameter that is most difficult to determine in a natural ditch. With reservations for the lack

of data for the evaluation of the modeling results, the model seems to provide a realistic picture

of variation of suspended material in Hestadbäcken. This makes it possible to estimate

the variations of particle-bound phosphorus in the runoff water from modeling results because

of the fact that the particle-bound phosphorus varies in the same way as suspended material.

The future use of HEC-RAS erosion modulus of fine-grained sediment will probably be limited

to areas where you have samples of very high quality and / or specifically examined the

cohesive parameters of the model, which requires experiments that can be performed only by

a few laboratories.

Place, publisher, year, edition, pages
2011.
Series
UPTEC W, ISSN 1401-5765 ; 11 006
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-350601OAI: oai:DiVA.org:uu-350601DiVA, id: diva2:1205526
Educational program
Master Programme in Materials Engineering
Supervisors
Examiners
Available from: 2018-05-14 Created: 2018-05-14 Last updated: 2018-05-14Bibliographically approved

Open Access in DiVA

No full text in DiVA

Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 1 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf