Difference between revisions of "Flood Forecasting"
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Our current plans for flood forecasting involve three phases: | Our current plans for flood forecasting involve three phases: | ||
| − | #Short-term | + | #Short-term trend extrapolation |
#Crest prediction | #Crest prediction | ||
| − | # | + | #Short-term forecasting |
===Short-term Prediction=== | ===Short-term Prediction=== | ||
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***"Based on current trend, the flood water will be [higher / lower] than the road after HH:MM pm/am" | ***"Based on current trend, the flood water will be [higher / lower] than the road after HH:MM pm/am" | ||
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===Crest Prediction=== | ===Crest Prediction=== | ||
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**Show confidence interval with prediction | **Show confidence interval with prediction | ||
**Example: | **Example: | ||
| − | ***Estimated crest at Gage C based on observed crest at Gage A: 5:10 pm (+/- 90 minutes) | + | ***Estimated crest at Gage C based on observed crest at Gage A: 5:10 pm (+/- 90 minutes) |
===Flood Forecasting=== | ===Flood Forecasting=== | ||
| − | + | ===== Model Based Short-term Prediction ===== | |
| + | Predict the next 4-12 hours at each gage. Most short term (4-12 hrs) flooding impacts in the lower valley will be the result of rain that has already fallen. | ||
| + | |||
| + | We should consider using the following inputs to build a model: | ||
| − | * | + | *Gage trend |
| + | *Upstream readings and trends | ||
| + | *Upstream major tributary readings and trends (Tolt, Raging, 3 forks) | ||
| + | *Meteorological readings from various stations in the watershed: | ||
| + | **Temperature | ||
| + | **Snowpack | ||
**Rainfall | **Rainfall | ||
| − | |||
| − | + | Predict the following for each gage: | |
| + | |||
| + | *Road crossing time | ||
| + | *Yellow / Red status change time | ||
| + | *Crest time | ||
| + | *Crest height | ||
Revision as of 21:06, 10 May 2020
Flood Forecasting
Our current plans for flood forecasting involve three phases:
- Short-term trend extrapolation
- Crest prediction
- Short-term forecasting
Short-term Prediction
By "short-term prediction", we mean extrapolating from current water levels in order to predict when near-term critical events like road-crossings will happen.
Linear Trend Extrapolation
- On the gage details page
- Create extrapolated readings every 15 minutes from the last reading until last reading + 6 hrs.
- Show extrapolated readings on chart with a different color.
- If extrapolated readings cross a road (rising or falling) display a notice:
- "Based on current trend, the flood water will be [higher / lower] than the road after HH:MM pm/am"
Crest Prediction
We want to be able to predict crest timing at a particular gage or area based on the timing of crests at upstream gages.
- For each gage build a model for each upstream gage that predicts the timing of the gage's crest based on the timing and height of the upstream gage
- For example, if gage C has two upstream gages, A and B. Build two models. One that predicts the timing of the crest of C based on A and one based on B.
- Only consider gages from USGS at the falls to USGS at Duvall
- Formalize the definition of a crest
- Something like: crest is confirmed after three down readings with no up readings.
- How do we handle a turbulent gage?
- How do we calculate the time of the crest? First highest point?
- Phase I: Height independent. Calculate median time based on past data.
- Phase II: Try to model hight. Maybe start with simple linear fit.
- Gage Details page:
- Show prediction based on nearest upstream gage that has crested
- Show confidence interval with prediction
- Example:
- Estimated crest at Gage C based on observed crest at Gage A: 5:10 pm (+/- 90 minutes)
Flood Forecasting
Model Based Short-term Prediction
Predict the next 4-12 hours at each gage. Most short term (4-12 hrs) flooding impacts in the lower valley will be the result of rain that has already fallen.
We should consider using the following inputs to build a model:
- Gage trend
- Upstream readings and trends
- Upstream major tributary readings and trends (Tolt, Raging, 3 forks)
- Meteorological readings from various stations in the watershed:
- Temperature
- Snowpack
- Rainfall
Predict the following for each gage:
- Road crossing time
- Yellow / Red status change time
- Crest time
- Crest height
