Flood Risk Assessment: Flood Hydrograph Simulation - Conceptual Model Flashcards

1
Q

What are the 3 types of Hydrological Models?

A
  • Empirical (Black Box)
  • Conceptual
  • Physically - based
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2
Q

What is the definition for an empirical model?

A

Uses input-output relationships from data, no process simulation

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3
Q

Definition for conceptual model?

A

Simplified process representation using stores and rules

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4
Q

Definition for physically-based model?

A

Solves physical laws via numerical methods

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5
Q

What are limitations of the unit hydrograph method?

A
  • Ignores evapotranspiration and baseflow
  • Assumes time-invariance
  • Doesn’t simulate full streamflow time series
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6
Q

Conceptual models use series of _______ with parameters to control flow and losses.

A

stores

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7
Q

Components within the water system?

A
  • Water demand
  • Water resources
  • Water networks
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8
Q

What are elements within the water demand?

A

Population, irrigation, indoor use

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9
Q

What are elements within the water resources?

A

Precipitation, groundwater, surface water

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10
Q

What are elements within the water networks?

A

Supply, leakage, wastewater, stormwater discharge

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11
Q

What is field capacity?

A

Max soil moisture held without drainage.

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12
Q

What is the wilting point?

A

Soil moisture level below which plants wilt.

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13
Q

What is Soil Moisture Deficit (SMD)?

A

Air content in the soil.

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14
Q

What is infiltration excess?

A

When rainfall exceeds the soil’s infiltration capacity.

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15
Q

What is saturation excess?

A

When soil is already fully saturated (SMD = 0).

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16
Q

What is NEAR (Non-Effective Area Runoff)?

A

Runoff from impervious surfaces that flows into pervious areas.

17
Q

What is the run off behaviour like in a pervious area?

A

Overland flow via infiltration/saturation excess

18
Q

What is the run off behaviour like in a impervious area?

A

Divided into NEAR and EAR

19
Q

Impervious Area Calculations
Formula
Evapotranspiration

A

PET = Ke × ET₀
AET = min(PET, IL, P)
- Ke = evaporation coefficient (0.1 for bare soil)
- IL = initial losses (mm)
- P = precipitation (mm)

20
Q

Formula
Surface Runoff

A

EAR = EA × max(P − AET, 0)
NEAR = (1 − EA) × max(P − AET, 0)- EA = % of area hydraulically connected to storm sewer

21
Q

Soil Moisture Calculation (Pervious Areas)
Formula:

A

PSMD(i) = SMD(i − 1) + PE(i) + R(i) − P(i) − NEAR(i)
Where:

SMD = Soil Moisture Deficit
PE = Potential Evaporation
AE = Actual Evaporation
R = Recharge
P = Precipitation
NEAR = Non-effective runoff

22
Q

When is AE(i) limited to WP − SMD(i−1)?

A

When PSMD(i) > WP

23
Q

True/False
If PSMD(i) < 0, excess precipitation becomes effective rainfall.

24
Q

What’s the first step before calculating streamflow using a routing model?

A

Estimate total runoff (EAR + NEAR), then apply routing equations.

25
Q

Why is a warm-up period needed?

A

To reduce error from poor initial conditions in storage values.

26
Q

True/False
The validation period should include extreme events to test robustness.

27
Q

What is calibration?

A

Adjusting parameters to fit observed data

28
Q

What is Validation?

A

Applying model to new data without re-tuning

29
Q

What is Warm-up?

A

Initial period excluded due to sensitivity to starting values

30
Q

What is OF?

A

Overland flow input

31
Q

What is Qb?

32
Q

What is Qs?

33
Q

What is Q?

A

Total flow = Qb + Qs

34
Q

Routing Function (Basic)
Formula

A

Qb(i) = Qb(i − 1) + (dQb/dt) × Δt
Qs(i) = Qs(i − 1) + (dQs/dt) × Δt

35
Q

Routing Function (Expanded)
Formula

A

dQb/dt = (R(i) − Qb(i − 1)) / Tb
dQs/dt = (OF(i) − Qs(i − 1)) / Ts