The hydrological limits of urbanization

1. The hydrological limits of urbanization R. Vedom Hydrology and Environment 905 823 6088 rimma@can.rogers.com www.hydrology.ca

2. 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.

3. 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

4. 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 ModelTM dQi = dQb*2^(Kmax + 0.618)

5. 0.0 -5.0 -10.0 -15.0 -20.0 -25.0 -30.0 -35.0 0 -40.0 0 Flow formation patterns in cross-sectional dimension 350 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

6. Qt = Qb + Qi + Qs 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

7. 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, removing

8. Precipitation Evapotranspiration Desert Tundra WT Air temperature EWBM: Equilibrium hypothesis

9. r Hlim 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

10. 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)

11. L 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)

12. 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)

13. 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

14. dQb indicates seasons 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)

15. 2.5 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)

16. Water fluxes in warm period, Heat fluxes in cold period Nr = 52 ÷ 60/year (Southern Ontario) 1 Precipitation Air temperature Recharge fluxes Nr

17. 1.0 0.9 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 urbanization

18. Drainage base beats (the SimpleBase Delineation Model application for level hydrograph delineation)

19. 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.

20. Thank you! Acknowledgement: I am sincerely thankful to Mickey, my retired neighbour, for her help in editing of the text Questions?