Loading in 5 sec....

The hydrological limits of urbanizationPowerPoint Presentation

The hydrological limits of urbanization

- 78 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about ' The hydrological limits of urbanization' - aulani

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### The hydrological limits of urbanization

R. Vedom

Hydrology and Environment

905 823 6088

www.hydrology.ca

Objectives/Content

- To introduce the SimpleBase Delineation ModelTM and its use
- to describe the flow formation process in terms of the model parameters
- to give definitions of the flow components obtained by this new hydrological tool
- based on the obtained results of flow separation for heavily urbanized watersheds to show how their parameters can quantitatively indicate the impact of urbanization.

The SimpleBase Delineation ModelTM use

- an independent tool for delineation of flow and level hydrographs (2002-2005)
- in the Equilibrium Water Balance Model, EWBM (2004)
- of the water quality formation process in the Separated Flow Approach (2003/2006)

the accurate

an auxiliary devise

the essential principle

Baseflow delineation algorithm:

if (Qt)t – (Qt)t-1 > dQb,

, otherwise (Qb)t = (Qt)t,

The key point for delineation is the mathematical definition of a discharge flux, which is the increase of the flow followed by its decrease or unchanged condition

(Qb)t = (Qt)t-1 + dQb

70

60

50

Nd

40

30

20

dQb

10

0

SimpleBase Delineation ModelTMdQi = dQb*2^(Kmax + 0.618)

-5.0

-10.0

-15.0

-20.0

-25.0

-30.0

-35.0

0

-40.0

0

Flow formation patterns in cross-sectional dimension350

Year-round or seasonally high WT;

Shallow river valley

4 ≥ Kmax ≤ 7

Kmax = 7÷ 9

Year-round or seasonally low WT;

Deep river valley

Kmax ≤ 3

Shallow drainage base: river mouth, between lakes

Qt = Qb + Qi

Qt = Qb

The Separated Flow Approach concept (stream quality formation process)

Ct = (Qb*Cb + Qi*Ci + Qs*Cs)/Qt

Ct = (Qb*Cb + Qi*Ci)/Qt

Ct = Cb

Ct, Qt - Total flow concentration and discharge

Cb, Qb - Baseflow concentration and discharge

Ci, Qi - Interflow concentration and discharge

Cs, Qs - Surface flow concentration and discharge

80

70

60

50

40

In different phases of water regime each flow component has different patterns

30

20

Velocity and travel time separation

2nd curve

1st rating curve

3rd rating curve

Velocity, m3/s

140

6

Fletcher’s Creek results: Baseflow – 58 hours (17 -122)

Interflow - 6.8 hours (2.2 – 18)

Storm flow – 2.2 hours (1.1 – 4.8)

120

5

100

4

80

3

60

2

Travel time, hours

40

1

Third rating curve

0

First rating curve

Second

20

1

11

21

31

41

51

61

71

81

91

101

111

121

131

Base

Inter

Storm

0

1

11

21

31

41

51

61

71

81

91

101

111

121

131

Dissolving, processing, removingHlim

dQb

A, km2

EWBM: Approximations based on incompressibility of water- Hlim - head of water table above the lowest stream level, within which the relation between H and I is linear
- r- radius of a circle, which area is equal to the area of the watershed

A, km2

Global regularities

dQbcorresponds to the highest Nd

- Manifestation of main physical features of water, continuity and incompressibility, in hydrosphere: the response of a river system to a recharge flux due to incompressibility of water displays degree of water continuity in air, water, and ground media.
dQi = dQb*2^(K + 0.618)

- Law of Structural Harmony of System: “The Generalized Golden Sections are invariants, which allow natural systems in process of their self-organization to find harmonious structure, stationary regime of their existence, structural and functional stability” (www.goldenmuseum.com)

Baseflow definition

- The baseflow component of river flow is the permanently continual inter-river groundwater discharge into the stream transmitting all drainage media and estimated by the dynamic uniformity limit dQb, the limit of uniform response of the drainage system to a recharge event: atmospheric water pressure flux
- The lowest uniform area sink in EWBM (2004)

Interflow definition

- Interflow is the temporary component of the river flow, which continuity is limited by the filtration and storage capacity of the river valley alluvial deposits and weathering zone.
- Dynamic buffer (2005)

Surface flow definition

- The surface or storm component of the river flow is the unbonded highly aggressive portion of the stream flow with a very short lifetime lasting from the continuity breakage until expanding over the flood plain for water bond restoration
- “Bonding plate”

1

3

2

Kmax ≤ 9, SFI ≤ 1% Nd « Nr

Weak indication of seasons Kmax ≥ 9, K = 7 SFI = 1 ÷ 10% Nd < Nr

1

2

No seasonal indication Kmax > 9, K = 5 SFI » 10% Nd ≤ Nr

3

Urbanization identification (clayish deposits, Y ≤ 0.1)8

0.7

7

0.6

1

2

Weak indication of seasons Kmax ≈ 9, K = 5, SFI = 5 ÷ 20%, Nd ≤ Nr

6

0.5

dQb indicates seasons

Kmax ≤ 4, SFI «1%, Nd ≤ Nr

2

5

1.5

0.4

No seasonal indication Kmax > 9, K = 5, SFI » 20%, Nd ≤ Nr

4

3

0.3

1

3

0.2

2

0.5

0.1

1

0

0

0

Urbanization identification (sandy and rocky deposits, Y ≥ 0.2)Heat fluxes in cold period

Nr = 52 ÷ 60/year (Southern Ontario)

1

Precipitation

Air temperature

Recharge fluxes Nr0.9

0.8

0.7

0.6

Water dynamic integrity index Nd/Nr

0.5

0.4

0.3

0.2

0.1

0.0

0

20

40

60

80

100

120

Watershed development, %

Y = 0.01-0.1

Y = 0.1 - 0.25

Impact of urbanizationDrainage base beats (the SimpleBase Delineation Model application for level hydrograph delineation)

Conclusions

The SimpleBase Delineation ModelTM is manifestation of main physical features of water, continuity and incompressibility, in entire hydrosphere: the response of a river system to a recharge flux due to incompressibility of water displays degree of water continuity in air, water, and ground media.

The certainty of the flow components’ definitions and regularity of their relationships opens a new possibility for quantitative assessment of the urbanization impact.

Hydrologically, the urbanization process can be identified as the process of gradual limitation of spatial interface between atmospheric and groundwater resulting in a continual drought.

The dynamic integrity index Nd/Nr for different geological conditions in combination with K and SFI determines the degree of the surface and groundwater disintegration, sustainable limits of which may be identified as the limits of urbanization.

Acknowledgement:

I am sincerely thankful to Mickey, my retired neighbour, for her help in editing of the text

Questions?

Download Presentation

Connecting to Server..