https://doi.org/10.7280/D16Q59

Description of file structure

Folder List:

1. Compound_Hazard_Model (Zenodo - Software)
2. MCMC_Rainfall_Simulator (Zenodo - Software)
3. Rainfall_Data (Dryad)

Supplemental Information:

1. GHCND_documentation.pdf

Detailed description of folder contents

1. Compound_Hazard_Model (Zenodo)

File List:

1. DayToMonth.mat
2. fires_100y_RIrng_1p25to2p86.mat
3. genprcp.m
4. MCMCv2_100yrsrlzn_EVA.mat
5. modelparams_v2.mat
6. P_EVA.m
7. pfireocc.m
8. returnlvls_v2.mat
9. WULF_Variable_Area.m
10. WULF_Variable_BurnSev.m
11. WULF_Variable_FireInt.m

Description of folder contents:

• WULF_Variable_Area.m, WULF_Variable_BurnSev.m, and WULF_Variable_FireInt.m are scripts that contain the compound hazard model and are identical except for the formatting of their output.  The scripts are designed to format the model output based on varying watershed area, burn severity, and fire interval, respectively.
• genprcp.m is a function script that generates a daily precipitation time series by running the Monte Carlo Markov Chain (MCMC) Rainfall Simulator.  
• P_EVA.m is a script used to determine the design capacity of flood infrastructure based on the return levels of the 50-year and 100-year storms from an extreme value analysis of a synthetic 100-year daily precipitation time series generated by the MCMC Rainfall Simulator.
• pfireocc.m is a function script that outputs the probability that a fire will occur during a given day of the fire season based on the user-specified fire return interval in years.

Relationship between files, if important:

• WULF_Variable_Area, WULF_Variable_BurnSev, and WULF_Variable_FireInt require the following codes and/or data files to run (i.e., these are dependencies of the scripts):
  • DayToMonth
  • fires_100y_RIrng_1p25to2p86
  • genprcp
  • MCMCv2_100yrsrlzn_EVA
  • modelparams_v2
  • pfireocc
  • returnlvls_v2

• If "options_loadprecip" is set equal to 1, then genprcp.m will require modelparams_v2.mat as a dependency.
• P_EVA.m requires MCMCv2_100yrsrlzn_EVA.mat as a dependency.

2. MCMC_Rainfall_Simulator (Zenodo)

File List:

1. assess_synthetic_series.m
2. dry_year.m
3. estimate_params_v2.m
4. modelparams_v2.mat
5. precipBTD.mat
6. process_precip_record.m
7. R_85yrs100rlzns.mat
8. run_MC_Generator.m
9. wet_year.m

Description of folder contents:

• process_precip_record.m is a script that cleans and formats the long-term daily precipitation dataset in preparation for estimating model parameters for the MCMC Rainfall Simulator.  It requires as dependencies the fiveComma Separated Values (CSV) files of rainfall data contained in the Rainfall_Data folder.
• estimate_params_v2.m is a script that estimates the transition probabilities and probability distribution function parameters needed to run the MCMC Rainfall Simulator.
• run_MC_Generator.m is a script that runs the MCMC Rainfall Simulator.
• assess_synthetic_series.m is a script that compares the statistics of the observed and synthetic rainfall time series to assess the performance of the MCMC Rainfall Simulator.
• dry_year.m and wet_year.m are function scripts that calculate the daily precipitation values in a dry year or wet year, respectively.

Relationship between files, if important:

• process_precip_record.m requires as dependencies the five CSV files of rainfall data contained in the Rainfall_Data folder.
• estimate_params_v2.m requires as a dependency precipBTD.mat.
• run_MC_Generator.m requires as dependencies modelparams_v2.mat, dry_year.m, and wet_year.m.
• assess_synthetic_series.m requires as dependencies precipBTD.mat and R_85yrs100rlzns.mat.

3. Rainfall_Data (Dryad)

File List:

1. BigTujungaDam_19320101_19501231.csv
2. BigTujungaDam_19510101_19701231.csv
3. BigTujungaDam_19710101_19901231.csv
4. BigTujungaDam_19910101_20101231.csv
5. BigTujungaDam_20110101_20201231.csv

Description of folder contents:

• The five CSV files contain daily precipitation data from 1932-2020 collected at the Big Tujunga Dam station in Los Angeles, California (ID: USC00040798) operated by the National Oceanic and Atmospheric Administration (NOAA).
• The file name convention of the CSV files is as follows:  [Station Name]_[Start Date of Record in YYYYMMDD Format]_[End Date of Record in YYYYMMDD Format].csv
  • For example, "BigTujungaDam_19320101_19501231.csv" indicates the station name is "Big Tujunga Dam," the start date of the precipitation record is 1 January 1932 and the end date of the precipitation record is 31 December 1950.

Relationship between files, if important: N/A

Data-specific information

The following metadata applies to all CSV files included in the "Rainfall_Data" folder:

• Number of variables: 8
• Variable List:
  1. STATION: station identification code
  2. NAME: name of the station (usually city/airport name)
  3. LATITUDE: latitude (decimated degrees w/northern hemisphere values > 0, southern hemisphere values < 0)
  4. LONGITUDE: longitude (decimated degrees w/western hemisphere values < 0, eastern hemisphere values > 0)
  5. ELEVATION: elevation above mean sea level (meters)
  6. DATE: date of record
  7. PRCP: precipitation (inches to hundredths place)
  8. PRCP_ATTRIBUTES: flag; see documentation file included as Supplemental Information (titled "GHCND_documentation.pdf") for more information
• Missing data codes: None (no empty cells are included)
• Specialized formats or other abbreviations used: None

Variable list for model scripts

This section contains variable lists pertaining to each model script in the repository. Each variable list in this section defines variables not covered by the preceding variable list (to prevent repetition of variables used across all scripts).

genprcp.m

• P_DW: probability of transitioning from dry year to wet year
• P_WW: probability of transitioning from wet year to wet year
• P01_dry_sm: 365 x 1 array of daily probabilities of transitioning from dry day to wet day during a dry year
• P01_wet_sm: 365 x 1 array of daily probabilities of transitioning from dry day to wet day during a wet year
• P11_dry_sm: 365 x 1 array of daily probabilities of transitioning from wet day to wet day during a dry year
• P11_wet_sm: 365 x 1 array of daily probabilities of transitioning from wet day to wet day during a wet year
• parmhat_dry: array of model parameters for probability distribution of precipitation magnitudes during a dry year
• parmhat_wet: array of model parameters for probability distribution of precipitation magnitudes during a wet year
• n: number of years to simulate
• m: number of daily time series realizations to simulate
• R: 365 x n x m 3D array of multi-year daily precipitation time series (units of mm)

P_EVA.m

• P:  precipitation time series (daily interval) generated by MCMC Rainfall Simulator; used as model forcing (mm)
• annmax:  time series of annual maximum precipitation (mm)
• returnT:  return periods for extreme precipitation events (years)
• returnP:  exceedance probabilities corresponding to the return periods in "returnT"
• PRLs_50_100:  50-year and 100-year return levels used to determine flood infrastructure capacity in the compound hazard model (years)

pfireocc.m

• T: return period for wildfires (years)
• fslen: length of fire season (days)
• p_ann: annual probabilty a wildfire does not occur
• p: probability of fire occuring on a given day during the fire season

WULF_Variable_Area.m, WULF_Variable_BurnSev.m, and WULF_Variable_FireInt.m

• alpha: fraction by which debris basin attenuates flood peak, with a value of 1 representing no flood peak attenuation (unitless)
• Crational: runoff coefficient used by the Rational Method to calculate peak runoff; represents ratio of runoff to rainfall (unitless)
• clean_rate: daily excavation rate for debris basin during wet season (m^3/day)
• clean_thresh: fraction of flood control infrastructure volume filled with sediment that triggers cleaning (unitless)
• daily_exc_basin: sediment removed from debris basin daily (m^3)
• daily_exc_chan: sediment removed from flood channel daily (m^3)
• J_c: sediment flux into flood channel (m^3)
• k: bulking factor; ratio of sum of water and sediment flows to water flow alone (unitless)
• k_design: design bulking factor used to size flood control infrastructure (unitless)
• k0: baseline bulking factor when watershed is unaffected by fire (unitless)
• k1: post-fire bulking factor; bulking factor value immediately after fire occurs (unitless)
• k1rng: two-element array of post-fire bulking factors representing range of possible bulking factors produced by a given wildfire; when wildfire occurs, post-fire bulking factor is uniformly randomly sampled from this range (unitless)
• nsims: number of simulations per run
• nyears: number of years in simulation; if simulation lasts less than a year, set to 1 (years)
• P_channel_design: magnitude of design storm used to size flood control infrastructure (mm)
• Q_c: volumetric water discharge into flood channel (m^3/s)
• Q_c_max: effective channel capacity (as a volumetric discharge) (m^3/s)
• Q_c_max_clean: capacity of clean flood channel (as a volumetric discharge) (m^3/s)
• Q_hazard: magnitude of overbank flows (i.e., flows in excess of flood channel capacity); includes both clear-water and bulked flows (m^3/s)
• Q_w: clear-water (or "water only") volumetric discharge from watershed outlet (m^3/s)
• RIfire: wildfire return interval (years)
• t: time (days)
• T_recovery: recovery timescale; time scale for watershed vegetation recovery after fire (days)
• T_w: time to peak; duration from beginning of storm to time of peak runoff, i.e., rising limb of triangular hydrograph (seconds)
• Vol_b: volume of sediment in debris basin (m^3)
• Vol_b_max: capacity of clean debris basin (m^3)
• Vol_c: volume of sediment in flood channel (m^3)
• Vol_c_max: capacity of clean flood channel (as a volume) (m^3)
• Vol_s: volume of sediment from watershed outlet (m^3)
• Vol_s_remov_basin: time series of volumes of sediment removed from debris basin due to excavation (m^3)
• Vol_s_remov_chan: time series of volumes of sediment removed from flood channel due to excavation (m^3)
• Vol_w: volume of water from watershed outlet (m^3)
• w: wet season cleaning waiting period; number of days with no rain needed before debris basin cleaning can commence (days)
• WatershedArea: contributing drainage area (km^2)

assess_synthetic_series.m

• btd_noNaN: observed 85-year (1932-2020) daily precipitation time series from Big Tujunga Dam in Los Angeles, CA with missing values removed (mm)

dry_year.m

• See variable list for file "genprcp.m," above

estimate_params_v2.m

• DD: number of times dry year follows dry year
• WW: number of times wet year follows wet year
• DW: number of times wet year follows dry year
• WD: number of times dry year follows wet year
• P_DD: empirical probability that dry year follows dry year
• P_WW: empirical probability that wet year follows wet year
• P_DW: empirical probability that wet year follows dry year
• P_WD: empirical probability that dry year follows wet year
• DD_wet: number of times dry day follows dry day during wet year
• WW_wet: number of times wet day follows wet day during wet year
• DW_wet: number of times wet day follows dry day during wet year
• WD_wet: number of times dry day follows wet day during wet year
• DD_dry: number of times dry day follows dry day during dry year
• WW_dry: number of times wet day follows wet day during dry year
• DW_dry: number of times wet day follows dry day during dry year
• WD_dry: number of times dry day follows wet day during dry year
• P01_wet: empirical probability that wet day follows dry day during a wet year; "P01_wet_sm" results from smoothing this variable using a moving mean
• P11_wet: empirical probability that wet day follows wet day during a wet year; "P11_wet_sm" results from smoothing this variable using a moving mean
• P01_dry: empirical probability that wet day follows dry day during a dry year; "P01_dry_sm" results from smoothing this variable using a moving mean
• P11_dry: empirical probability that wet day follows wet day during a dry year; "P11_dry_sm" results from smoothing this variable using a moving mean

process_precip_record.m, run_MC_Generator.m

• No additional variables to define

wet_year.m

• See variable list for file "genprcp.m," above

Sharing/Access information

• Licenses/restrictions placed on the data:  CC0
• Licenses/restrictions placed on the software:  GNU General Public License v3.0 or later
• Licenses/restrictions placed on the supplemental information: Creative Commons Attribution 4.0 International (CC BY 4.0) license
• Publications that cite or use the data:  Jong‐Levinger, A., Banerjee, T., Houston, D., & Sanders, B. F. (2022). Compound post‐fire flood hazards considering infrastructure sedimentation. Earth's Future, 10(8), e2022EF002670.
• The daily precipitation data were downloaded from the Climate Data Online database operated by the National Oceanic and Atmospheric Administration. Daily precipitation values from the Big Tujunga Dam rain gauge station (ID: USC00040798) from 1 January 1932 to 31 December 2020 were used to develop the precipitation model. Direct link to data used to develop the precipitation model: https://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations/GHCND:USC00040798/detail

Code/Software

MATLAB Version 9.10.0.1602886 (r2021a) was used to write and run the model scripts.