WinterFloods

This code includes the data processing and analysis pipelines and functions to undertake a wide range of fluvial and pluvial flood frequency analysis, putting the key events of 2019-2021 into context, and compares the antecedent conditions to previous extreme flooding events. The data required to undertake the analysis is not included, but is available from the NRFA website, the EA Hydrology Data Explorer, The Met Office (for Had-UK), or by request from the Environment Agency.

Project: Winter Floods 2019-2021

Author: UKCEH

Version: 1.0 2024-04-30

Version: 1.1 2024-07-22

Description of files in Final Code Directory

Catchment Rainfall

• /CatAvg_HUKG_parallel_FINAL.R
  • Script for use on JASMIN to get catchment averages from HadUK daily rainfall 1km dataset
• /H24_events_RPs_extract_FINAL.R
  • Find event return periods for depths extracted by H24_event_totals.R
• /H24_events_RPs_xml_FINAL.R
  • Find event return periods for depths extracted by H24_event_totals.R
• /H24_events_totals_FINAL.R
  • Extraction of rainfall depths
• /H24_extract_CatAvg_FEH22_rainfall_FINAL.R
  • Extract rainfall AEP levels from FEH22 grids

Clustering

• /CLUSTER_ANALYSIS_FINAL.R
  • Script to perform cluster analysis of POT series.
• /cluster_analysis_functions_FINAL.R
  • Functions for use in Cluster Analysis

Context

• /Aligning_events_FINAL.R
  • Matching storms with antecedent conditions
• /SummarisingFunctions_FINAL.R
  • Key functions for context analysis
• /trendvsUrbanvsChange_FINAL.R
  • Matching Land cover to catchments

COSMOS

• /Closest_COSMOS_to_each_station.R
  • Find closest COSMOS site to each river gauging station and export table
• /cosmos_at_event_FINAL.R
  • Matching storms with antecedent conditions
• /Highest_VWC_per_site_FINAL.R
  • Find single highest COSMOS volumetric water content for each site
• /Plot_highest_7-day_VWC_per_site_FINAL.R
  • Plot highest COSMOS volumetric water content for each site
• /Rank_days_FINAL.R
  • Rank COSMOS volumetric water content on each calendar day
• /Rank_month_quarters_FINAL.R
  • Rank COSMOS volumetric water content on each calendar monthquarter

Groundwater

• /Extract_GW_for_events_FINAL.R
  • Extract highest groundwater within 5 days (BEFORE only) of given events at the closest GW station to the flow station recording the event
• /GW_AMAX_FINAL.R
  • Load each groundwater record, extract WY AMAX
• /GW_AMIN_FINAL.R
  • Load each groundwater record, extract WY AMIN
• /GW_event_RPs.R
  • Fit GEV distribution to groundwater AMAX/AMIN
• /GW_FullRec_FINAL.R
  • Load each groundwater record, extract WY AMAX for full record

Nonstationary

• /nonstat_run_FINAL.R
  • Nonstationary flood frequency analysis from nonstat package
• /nonstat_run_phys.R
  • Extra plotting functions for nonstat data.
• /CovariatesForNonst_FINAL.R
  • Getting covariates for nonstationary analysis

Flow

• /all_amax_with_ranks_FINAL.R
  • Get all AMAX and bundle into a single file for extra analysis
• /Event_ranks_from_POT_files_FINAL.R
  • Load compute ranks from annual maxima at NRFA stations from .pt files.
• /Event_RPs_from_AMAX_files_FINAL.R
  • Load compute return periods from annual maxima at NRFA stations.
• /peakflow_uncertainty.R
  • Compute confidence intervals on peak flow using bootstrapping methods

Level

• /level_ranking_compute_compile_FINAL.R
  • Compute ranks of stage measurements for key events
• /LevelRanking_FINAL.R
  • Stage extraction for event ranking of stage for all data sources

Rainfall_monthly

• /Add_rank_&_RP_to_period_AMAX_FINAL.R
  • Read 30-, 60-, 90- and 180-day rainfall maxima, and add ranks and return periods
• /Add_rank_&_RP_to_WF_AMAX_FINAL.R
  • Read 30-, 60-, 90- and 180-day rainfall maxima, and add ranks and return periods
• /Distribution_Rain_MDay.R
  • Read M-day rainfall maxima, choose best and acceptable distributions for each catchment, hence overall best
• /Extract_monthly_AMAX_FINAL.R
  • Read catchment-average daily rainfalls, assign to water years, aggregate monthly totals, find 1, 2, 3 and 6-month maxima
• /Extract_WF_period_AMAX_FINAL.R
  • Read catchment-average daily rainfalls, find 30-, 60-, 90- and 180-day maxima with arbitrary start times within June 2019-June 2021
• /Generate_L-moments_FINAL.R
  • Read 1, 2, 3 and 6-month AMAX, calculate and write L-moments, median, and other derived statistics

Rainfall_pt

• /I4PLA.R
  • FEH22 internal functions
• /Pluvial_event_RPs_FINAL.R
  • Use FEH22 to find event return periods for depths extracted by Pluvial_event_totals_FINAL.R
• /Pluvial_event_totals_FINAL.R
  • Find pluvial event totals for given events

Rate_of_rise

• /PlotsForRoR.R
  • Rate of rise plots
• /Rate_of_rise_FINAL.R
  • Rate of rise calculations
• /Trends_of_ror_FINAL.R
  • Compute trends in rate of rise at all stations

Volumes

• /Extract_max_week_volumes_NWeek_FINAL.R
  • Combine 15-minute records from Q 15 and Q 15 IR, Extract maximum volumes per water year, 1, 2, 4, 6, 8-week maximum volumes with START DATE
• /volume_ranking_FINAL.R
  • Ranking volumes within volume AMAX series
• /VolumeDDFs_FINAL.R
  • Plot DDF curves for volume relationships

Acknowledgements

The Winter Floods 2019-21 Project SC35752 (Hydrological analysis of the 2019-2021 flooding), within the Environment Agency Modelling and Mapping Framework. The tool was updated in 2024.

Documentation The main README files contain column name and type specificaton for all the necessary tables to undetake the analysis.

Licences The code was written by UK Centre for Ecology & Hydrology.

All the code is released under the Open Government Licence, except where the packages therein are based on Creative Commons licences.

Support Please send enquiries to FloodHydrology@environment-agency.gov.uk