Time-varying analysis of parameter sensitivity at multiple evaluation scales for hydrologic and sediment modeling

Transcription

1 1 Time-varying analysis of parameter sensitivity at multiple evaluation scales for hydrologic and sediment modeling Presented by: Hui Xie Authors: Hui Xie, Zhenyao Shen *, Lei Chen, Guoyuan Wei Beijing Normal University July 2016

2 Outline 1 Background Introduction Objectives 2 3 Methodology Watershed description Model setup FAST+Moving windows Results and discussion Hydrology section Sediment section 3 Summary

3 Background

4 Background 1 Time-varying analysis Supports model calibration Which period are helpful for identification? Under which condition a specific process matters? 2 Multiple evaluation scales Maximize information content Guide measurement campaigns Different processes act over different time scales

5 Background 3 Time-varying + multiple evaluation scales for SEDIMENT modeling No previous research concerned Support management plan 4 Objective Improve the understanding of hydrologic and sediment processes

6 Methodology

7 Methodology 1 Study site Zhangjiachong watershed Located at the head of TGRA, 1.6km 2

8 Methodology 2 Model setup HSPF IMPERLND Watershed PERLND RCHRES

9 Model setup Hydrology Section Flows & Storages

10 Model setup Hydrology Section Flows & Storages Sediment Section Detachment & Washoff Scour & Deposition

11 1 Hydrologic parameters Parameter Description Unit Possible range LZSN Low zone nominal soil moisture storage in INFILT Index to mean soil infiltration rate in./h KVARY Parameter to describe non-linear groundwater recession rate in AGWRC Groundwater recession rate day DEEPFR BASETP AGWETP Fraction of infiltrating water which enters deep aquifers none Fraction of potential evapotranspiration which fulfilled only as outflow exists. none Fraction of remaining evapotranspiration that be met from active groundwater storage. none CEPSC Interception storage capacity. in UZSN Nominal upper zone soil moisture storage. in INTFW Interflow inflow parameter. none IRC Interflow recession parameter. day LZETP Index to lower zone evapotranspiration. none

12 2 Sediment parameters Parameter Description Unit Possible range SMPF Management Practice (P) factor from USLE none KRER Coefficient in the soil detachment equation in./h JRER Exponent in the soil detachment equation in AFFIX Daily reduction in detached sediment day COVER Fraction land surface protected from rainfall none KSER Coefficient in the sediment washoff equation none JSER Exponent in the sediment washoff equation none TAUCD1 Critical bed shear stress for deposition in TAUCS1 Critical bed shear stress for scour in TAUCD2 Critical bed shear stress for deposition of silt none TAUCS2 Critical bed shear stress for scour of day

13 Methodology 3 Sensitivity analysis Fourier Amplitude Sensitivity Test (FAST) Global method Variance decomposition Non-linear models Computationally efficient Saltelli et al. (1999)

14 Methodology 3 Sensitivity analysis Fourier Amplitude Sensitivity Test (FAST) Global method Parameters uniformly distributed Variance decomposition Non-linear models 50,000 samplings for hydrologic parameters Computationally efficient 20,000 samplings for sediment parameters

15 Methodology 4 Multiple moving windows Objective function Moving window sizes 2, 4, 8, 30, 60, 180, 360, 540, 720 days (Massmann et al., 2014)

16 Results and Discussion

17 Results and discussion 1 Model calibration for daily streamflow and sediment NSE=0.82 R 2 =0.83 NSE=0.59 R 2 = y = x R² =

18 18 Results and discussion 2 Time-varying sensitivity of HYDROLOGIC parameters 1 Base flow AGWRC, KVARY ET, water loss LZETP, BASETP, DEEPFR, CEPSC Parameter groups Interflow INTFW, IRC 2 4 Moisture redistribution LZSN, UZSN, INFILT 3

19 1 Base flow 19

20 1 Base flow High sensitivities in the full period Especially high in dry periods More than 180 days for identification Base flow is critical Should be calibrated Long length of observation

21 2 Interflow

22 2 Interflow Highest sensitivities in wet period Strong correlation with precipitation Monitoring plan arranged according to the sensitive areas days for identification

23 3 Moisture redistribution

24 3 Moisture redistribution LZS more steady UZS active in the first year

25 3 Moisture distribution

26 3 Moisture distribution Active in the first year when water fill up the lower storages Percolation & Infiltration more important than water movement into IFS

27 4 ET

28 4 ET

29 4 ET ET from LZS is critical Long length of monitoring required Impact on wet periods

30 30 Results and discussion 2 Time-varying sensitivity of SEDIMENT parameters 1 Detachment KRER, JRER Controllable SMPF, COVER Parameter groups Washoff KSER, JSER 2 4 Scour/deposition TAUCD, TAUCS 3

31 TSS (mg/l) 1 Detachment

32 1 Detachment Erodibility of the Soil Type Strong correlation with Precipitation

33 TSS (mg/l) 2 Washoff

34 2 Washoff Effects of surface condition and flow Sensitive in most of the time 45 days or more required for identification Management practices impact on KSER

35 TAU 2 Scour/deposition

36 TAU 3 Scour/deposition

37 TAU 3 Scour/deposition Determine the Sediment dynamics in reach Sensitivity and evaluation scales Varies as Bed Shear Stress changes Practices in the channels make sense

38 TSS(mg/L) 4 Controllable

39 4 Controllable Similar to P and C factors in USLE High sensitivity during the wet season Management practices are effective when evaluated in scales of more than 60 days

40 Summary

41 Summary At what time period specific parameters are sensitive is defined. Over what length of measurement to maximize the sensitivity signals is defined. The results help support measurement campaigns, calibration, and management plan.

42 THANK YOU Any question and suggestion? Contact: