the university of nottingham hervé p. morvan march 2006
TRANSCRIPT
![Page 1: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/1.jpg)
The University of Nottingham
Hervé P. Morvan
March 2006
![Page 2: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/2.jpg)
Joint SHSG-ICE One-Day Seminar:A New Challenge for Water Engineers –
CAR 2005
Hervé P. Morvan
March 2006
Modelling and Analysis of River Changes
linked to Ecological Considerations
![Page 3: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/3.jpg)
Content The School of Civil Engineering CFD Group and
CFD@Nottingham.
Recent NAFEMS-ERCOFTAC Meeting on Quality and Reliability of CFD Simulations.
Ecological Systems (Modelling of)
River Modelling
Applications of CFD to the Analysis of River Changes and Associated Ecological Impacts.
![Page 4: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/4.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2006
Introduction
![Page 5: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/5.jpg)
Activities
NCI
CFD Group - 4 Staff
- 2 Post-Docs
- 10+ PhDs
- 6 MEng/M.Sc.Civil Engineering
CFD@Nottingham:
- Across Faculty
- Joint Course/Research
- Seminar/Conference
Wind Engineering and Atm. Models
FSIReactive Flows
Comfort, Fire and Safety
Hydraulics and Water
Engineering
Large Scale
Radial Basis Functions
![Page 6: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/6.jpg)
Nottingham CFD@Nottingham is a joint effort project with
Mechanical and Chemical Engineering, and Applied Mathematics:
run seminars and evening lectures: « Geophysical Turbulence » on April 26th « SHP – An Overview » on May 17th
run CFD courses and the EPSRC « Summer School in Industrial CFD », June 19th-23rd:
[email protected] www.nottingham.ac.uk/cfd
Several ERCOFTAC SIGs are based in Nottingham: www.ercoftac.org
![Page 7: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/7.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2005
Heard at a Recent NAFEMS-ERCOFTAC meeting…
![Page 8: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/8.jpg)
Environmental CFD “Verification and Validation in Uncertain
Worlds”, Joint NAFEMS-ERCOFTAC Seminar, Nottingham, Sept. 2005.
Modelling natural features such as river channels is not easy.
Issues with feasibility, choice of protocole etc.
![Page 9: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/9.jpg)
Geometries They are not always simple to acquire for river
channels, countryside topographies, urban environments.
Looking at river channels for example, these are irregular, dynamic systems with multiple boundaries and sources.
Mapping the ground is difficult, costly: vegetation, buildings, ponds.
![Page 10: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/10.jpg)
Spatial Resolution Size of grid cells used to represent the
surface...
![Page 11: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/11.jpg)
Comparative Work
![Page 12: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/12.jpg)
Scales... Domain size is usually large and complex.
Catchment to structure scale.
Physical scales are multiple: Which physical scales do we, or can we, model?
Grain and form roughness, vegetation, buildings: Momentum and energy losses.
Turbulence scales.
![Page 13: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/13.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2006
Modelling of Ecological Systems
![Page 14: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/14.jpg)
More Uncertainty… “We can explain observed phenomenon but
not necessarily predict how species will react to imposed changes” (Clifford, 1998).
“Who decides if you design a river specifically to improve habitat for salmonids? – The answer is God decides” (Hey, 1998).
![Page 15: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/15.jpg)
When there is a will… “Too many restorations in the past have been carried
out with no quantitative prediction of the impact on the flow or on the environmental enhancements that will be achieved. Increasingly suitable quantitative methods are becoming available and it is a challenge for the research community to provide methods, in collaboration with the ecologists, which will predict the true impact of restoration. It is time that we replaced the guess work with accurate prediction”
(1997, ICE Meeting on Eco-Hydraulics).
![Page 16: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/16.jpg)
Methodologies Various methodologies exist:
IFIM – flow model, depth, suitability curves CASIMIR – more elaborate RCHARC – similarity principle and variability SERCON – survey and score (potential) RIVPACS and HABSCORE – similar (predictive)
IFIM, CASIMIR and RCHARC involve some hydraulics (dominantly 1-D) – Combined approach.
IFIM is the most commonly used. Quite sensitive however.
![Page 17: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/17.jpg)
Ecological Modelling Clifford et al (2005) indicate that the data form
invites modelling, however difficult.
Issues of scales are important here as well. So is resolution: Fish habitat could be at the scale of a large boulder…
Clifford et al (2005) also indicate that we may want to forget a rigid, “numerical” use of modelling…
![Page 18: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/18.jpg)
Nottingham “It is a challenge to the habitat modelling
community to decide what is the required level of accuracy (1D, 2D or 3D) for assessing habitat improvements” (Swindale, 1999).
PhD work to implement and compare various methods.
![Page 19: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/19.jpg)
General Env. Hydraulics Beyond ecological models, there are other
applications linking river hydraulics and the environment.
Uncertainty is found in many other aspects, as underlined in the examples chosen here, e.g. in Sanders et al. (2005) on urban pollution in a channel:
“In cases involving FIB concentrations, uncertainties may be 200-500%. By comparison, uncertainty associated with the mathematical model and numerical method are relatively small, roughly 20% and 1% respectively” .
![Page 20: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/20.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2006
River Modelling
![Page 21: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/21.jpg)
River Modelling Common in 1-D; well established.
Growing in 2- and 3-D for specific applications, e.g. flood propagation and detailed flow past man-made structures respectively.
Validation is still needed and difficult, but better definitions for roughness and systematic methods are emerging together the use of with 2- and 3-D.
Of course, it all depends on how we use the modelling outcome.
![Page 22: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/22.jpg)
Nottingham In spite of the aforementioned difficulties,
modelling is improving rapidly and is proving very good at capturing trends.
There is a lot of on-going work: FRMRC work – CFD Group, Geography and
IESSG. Combining 1-, 2- and 3-D – horse for courses. Using aerial/satellite data to look at roughness. Using 3-D to inform 1-D models, e.g. SKM.
![Page 23: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/23.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2006
Examples
![Page 24: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/24.jpg)
Examples Swindale (1999) – fish habitat
Sanders et al. (2005) – pollution
Neary et al. (2005) – man made structures
There are many more in River Research and Applications, Hydrological Processes, Water Research, ASCE J. Hydraulic Engineering.
![Page 25: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/25.jpg)
Swindale (1999) Implementation of the IFIM framework in
several models, including 2- and 3-D.
River restoration.
River Idle.
![Page 26: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/26.jpg)
Swindale (1999)
![Page 27: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/27.jpg)
Swindale (1999)
![Page 28: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/28.jpg)
Swindale (1999)
![Page 29: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/29.jpg)
Swindale (1999)
![Page 30: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/30.jpg)
Swindale (1999) 2- and 3-D modelling most useful to look at
detailed/localised effects, e.g. due to work on the channel, and spatial variability.
This is also picked on by Clifford et al. (2005).
![Page 31: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/31.jpg)
Sanders (2005) Modelling the impact, transport, growth and
decay of bacteria in a stream.
Identifying the “dominant” processes and sources.
![Page 32: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/32.jpg)
Sanders (2005) Use of Faecal Indicator Bacteria (FIB).
Model predicts the advection, dispersion and die-off of TC, EC, ENT using a depth integrated formulations.
“In Talbert Marsh, it is not clear whether FIB concentration are predominantly controlled by urban runoff, erosion of contaminated sediments, birds faeces, or some combination of these factors.” (Sanders et al., 2005)
![Page 33: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/33.jpg)
Sanders (2005)
![Page 34: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/34.jpg)
Sanders (2005)
![Page 35: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/35.jpg)
Sanders (2005) Sanders is able to conclude that:
Surface concentrations of total coliform, Escherichia coli and enterococci in the wetland are driven by urban runoff loads and resuspended sediments.
Sediment, Sanders concludes, act as a reservoir of FIB and adds that this finding is important to temper the expectation that hydrodynamically active wetland serve to process FIB from runoff and other sources.
![Page 36: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/36.jpg)
Modelling of River Changes& Ecological Considerations
Hervé P. Morvan
2006
Concluding Remarks
![Page 37: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/37.jpg)
Concluding Remarks The scope for the regulations is considered under 5
main headers in the Act: controls over pollution; abstraction; impoundments; building, engineering and other works; duty to use water efficiently.
Impact assessment: One particular statement is worth noting as an excerpt of the
overall section, p. 15: “[the] site-specific assessment will typically involve the use of models or defined rules for decision-making”.
![Page 38: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/38.jpg)
Concluding Remarks River modelling is very good at picking up
trends.
River modelling alone or combined with some ecological models can assist in evaluating the impact of a solution, e.g.:
Fish habitat (river restoration/management); Pollutant transport; Hydraulic design.
![Page 39: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/39.jpg)
Concluding Remarks Naturally more validation work and guidelines
are necessary.
At Nottingham we are: Building up validation libraries; Preparing and distributing Best Practise
Guidelines (Nottingham, ASCE EMD Fluids Cmmttee, NAFEMS);
Using validated CFD to learn more about specific mechanical processes AND feeding the information back into application specific codes.
![Page 40: The University of Nottingham Hervé P. Morvan March 2006](https://reader036.vdocuments.site/reader036/viewer/2022062713/56649f435503460f94c63d6f/html5/thumbnails/40.jpg)
Thank you.
School of Civil Engineering, CFD Group,
Coates Building, University Park
NG7 2RD Nottingham