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# 3.4 IUKWC Workshop Freshwater EO - Kumar Gaurav - Jun17

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Remote sensing to estimate the mean discharge of rivers from the Himalayan Foreland.
Kumar Gaurav (Indian Institute of Science Education and Research Bhopal Madhya Pradesh)

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### 3.4 IUKWC Workshop Freshwater EO - Kumar Gaurav - Jun17

1. 1. Remote sensing to estimate formative water discharge of the Himalayan Foreland rivers. Department of Earth & Environmental Sciences Indian Institute of Science Education and Research, Bhopal (India-UK Water Centre) 19 June 2017 Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 0 / 14
2. 2. Introduction Flow discharge and its measurement: Q=? v Water discharge in river channels is an important quantity of hydrologic cycle Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 1 / 14
3. 3. Introduction Flow discharge and its measurement: Q=? v Water discharge in river channels is an important quantity of hydrologic cycle It is needed to understand: - Terrestrial water budget - Flood management - River morphology - Water security etc..... Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 1 / 14
4. 4. Introduction Flow discharge and its measurement: Q=? v Water discharge in river channels is an important quantity of hydrologic cycle It is needed to understand: - Terrestrial water budget - Flood management - River morphology - Water security etc..... Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 1 / 14
5. 5. Hydraulic geometry relationship Width(W ) = αW QβW (1) Depth(H) = αHQβH (2) Slope(S) = αS Q−βS (3) [Leopold and Wolman 1957] Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 2 / 14
6. 6. Discharge estimation: Conventional approach Stage-Discharge rating curve: (x10) 30 60 90 0 20 10 0 Discharge (Q) Depth(H) Flow H [source: Sanders 1998] Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 3 / 14
7. 7. Discharge estimation: Conventional approach Stage-Discharge rating curve: (x10) 30 60 90 0 20 10 0 Discharge (Q) Depth(H) Flow H [source: Sanders 1998] Site dependent Requires a gauging station Assumes river ﬂows as single-thread and have a stable boundary Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 3 / 14
8. 8. Discharge estimation: Conventional approach Stage-Discharge rating curve: (x10) 30 60 90 0 20 10 0 Discharge (Q) Depth(H) Flow H [source: Sanders 1998] Site dependent Requires a gauging station Assumes river ﬂows as single-thread and have a stable boundary Flo w Flow Flow ? Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 3 / 14
9. 9. Discharge estimation: Remote sensing approach Width-Discharge rating curve: Discharge Width 0 1000 2000 400 800 (Q) (W) [source: Smith et al., 1996] At a station rating curves. Assumes river is stable. Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 4 / 14
10. 10. Alluvial river: channel migration Channels are mobile in space and time Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 5 / 14
11. 11. Width-discharge relationship: Physical basis Threshold theory µ = Tangential force Normal force µ is Coulomb friction coeﬃcient For a given discharge this mechanism sets the size of a channel. [Glover and Florey 1951, Henderson 1963, and Seizilles et al 2013] Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 6 / 14
12. 12. Threshold theory: regime relations W = π µ3/4 3 23/2 K [1/2] √ Cf g1/4 1 L1/4 √ Q (Lacey’s law) L = θt (ρs − ρf ) ds µρf W and Q are width and discharge θt is threshold parameter ds is grain size Cf is Chézy friction coeﬃcient µ is Coulomb’s friction coeﬃcient ρf and ρs is ﬂuid and water density Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 7 / 14
13. 13. Himalayan foreland rivers and threshold channel: width 10 1 10 2 10 3 10 4 Discharge [ ] 10 1 10 2 10 3 Width[m] Multiple Single channel Threshold theoryBest ﬁt [Gaurav et al, 2017 (In press)] Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 8 / 14
14. 14. Hypothesis 10 1 10 2 10 3 10 4 W Discharge Width Regime relation 10 1 10 2 10 3 10 4 [m] [m3 /s] Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 9 / 14
15. 15. Locations 0 650 km Indus Brahmaputra Indo-Gangetic Basin River 0 650 km Himalayan Frontal Thrust Indus Brahm aputra Chenab Ganges Kosi Teesta N Bhimnager barrage Panjnad Kotri barrage Farakka barrage Anderson br Kaunia Bahadurabad Paksay Data Landsat satellite images (resolution 30 m) Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 10 / 14
16. 16. Discharge at a section Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 11 / 14
17. 17. Discharge at a section Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 11 / 14
18. 18. Discharge at a section Total discharges; Qtot = Q1 + Q2 + Q3 Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 11 / 14
19. 19. Hydrograph Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 10 2 10 3 10 4 Discharge[m3 s−1 ] Kosi Bhimnagar barrage Image derived Average In-situ Average Month Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 12 / 14
20. 20. Conclusions Average annual discharge can be estimated using remotely sensed images. Width-Discharge regime relation established in this study is equally valid for multiple and single-thread river system. This ﬁnding could be extend to alluvial rivers located in diﬀerent environments worldwide. Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 13 / 14
21. 21. Thank you Kumar Gaurav (IISER, Bhopal) Remote sensing to estimate discharge 14 / 14