Data Exploration
Background
There are two hypotheses about flooding at the Robeson Rolling Mill/PCC Clubhouse to resolve:
Have changes to the Mill’s surroundings over time increased flooding and, as a result, increased the need for structural maintenance to the Mill and its retaining wall?
Deep scouring in the retaining wall’s structure and photographs of the area suggested there had been notable changes in the surroundings since PCC’s lease began in 1905. Below is the oldest known picture of the Mill, taken in 1877 when the Colony on the Schuylkill, AKA Schuylkill Fishing Club, first leased the land and Mill. (Middle right shows three members, two in the white cooking smocks.) The photo was taken from the Creek’s east bank at an elevation that appears to be upwards of 20 feet lower than the bank/ramps to Kelley Drive & the City Line Twin Bridges are now.
Other photos suggest the east bank was about ten to fifteen feet high at this time, the fifteen-foot top being where there was a footbridge/carriage bridge from East River Drive, c. 1880-1930. This same spot will become the bike path in a few years, with the remaining abutments being built over it. (1827 postcard.)
To the Mill’s east, going down river, there was a bridge to City Line avenue, but East River Drive (the pre-Kelly Drive name) was not, it appears, right next to the east bank as we see it now; see the two aerial photos below, 197 and 1933.
1933 photo; the body of water is/was Gustine Lake, and it’s reasonable to believe that when there were major floods, the water from the Creek and backflow from the River went over the east bank into what was then a 60-80 acre floodplain.
Data
In this document, data comes from USGS peak and mean daily CFS data measured at the Wissahickon Creek and the Fairmount Dam.
Methods
Simple visualizations of peak and CFS data are presented over time. Plots are grouped by decade, with each year within the decade plotted individually. Data is presented in 4 ways:
- As observed, all points.
- As observed, 30-day moving average. This is a smoothing method to mitigate extreme peaks and show larger temporal trends.
- log10-transformed, all points. As the observed data does have extremes that are magnitudes above some baseline, this method smooths out these differences and allows for visualization of larger trends.
- log10-transformed, 30-day moving average. A combination of the two methods described above.
All analyses are performed in R version 4.5.2.
Peaks
Mean Daily CFS
These plots show mean daily data at the Fairmount Dam and Wissahickon Creek grouped by decade. Click the tabs to see each source.
Mean Daily CFS (30-Day Moving Average)
These plots show annual peak data at the Fairmount Dam and Wissahickon Creek grouped by decade and smoothed using a 30-day moving average. Click the tabs to see each source.
Mean Daily CFS (log10)
These plots show annual peak data at the Fairmount Dam and Wissahickon Creek grouped by decade and log-10 transformed. Click the tabs to see each source.
Mean Daily CFS (log10, 30-Day Moving Average)
These plots show annual peak data at the Fairmount Dam and Wissahickon Creek grouped by decade and log-10 transformed and smoothed using a 30-day moving average. Click the tabs to see each source.
Appendix
U.S. Geological Survey National Water Information System
Retrieved: 2025-11-23 08:37:08 EST
———————————- WARNING —————————————-
Some of the data that you have obtained from this U.S. Geological Survey database
may not have received Director’s approval. Any such data values are qualified
as provisional and are subject to revision. Provisional data are released on the
condition that neither the USGS nor the United States Government may be held liable
for any damages resulting from its use.
More data may be available offline.
For more information on these data, contact USGS Water Data Inquiries.
This file contains the annual peak streamflow data.
This information includes the following fields:
agency_cd Agency Code
site_no USGS station number
+ peak_dt Date of peak streamflow (format YYYY-MM-DD)
+ peak_tm Time of peak streamflow (24 hour format, 00:00 - 23:59)
+ peak_va Annual peak streamflow value in cfs peak_cd Peak Discharge-Qualification codes (see explanation below) + gage_ht Gage height for the associated peak streamflow in feet + gage_ht_cd Gage height qualification codes +year_last_pk Peak streamflow reported is the highest since this year + ag_dt Date of maximum gage-height for water year (if not concurrent with peak) + ag_tm Time of maximum gage-height for water year (if not concurrent with peak + ag_gage_ht maximum Gage height for water year in feet (if not concurrent with peak + ag_gage_ht_cd maximum Gage height code
Sites in this file include:
USGS 01474500 Schuylkill River at Philadelphia, PA
Peak Streamflow-Qualification Codes(peak_cd):
1 … Discharge is a Maximum Daily Average
2 … Discharge is an Estimate
3 … Discharge affected by Dam Failure
4 … Discharge less than indicated value,
which is Minimum Recordable Discharge at this site
5 … Discharge affected to unknown degree by
Regulation or Diversion
6 … Discharge affected by Regulation or Diversion
7 … Discharge is an Historic Peak
8 … Discharge actually greater than indicated value
9 … Discharge due to Snowmelt, Hurricane,
Ice-Jam or Debris Dam breakup
A … Year of occurrence is unknown or not exact Bd … Day of occurrence is unknown or not exact Bm … Month of occurrence is unknown or not exact
C … All or part of the record affected by Urbanization,
Mining, Agricultural changes, Channelization, or other
F … Peak supplied by another agency
O … Opportunistic value not from systematic data collection
R … Revised
Gage height qualification codes(gage_ht_cd,ag_gage_ht_cd): 1 … Gage height affected by backwater
2 … Gage height not the maximum for the year
3 … Gage height at different site and(or) datum
4 … Gage height below minimum recordable elevation 5 … Gage height is an estimate 6 … Gage datum changed during this year
7 … Debris, mud, or hyper-concentrated flow
8 … Gage height tidally affected
Bd … Day of occurrence is unknown or not exact Bm … Month of occurrence is unknown or not exact
F … Peak supplied by another agency
R … Revised
Session Information
R version 4.5.2 (2025-10-31)
Platform: aarch64-apple-darwin20
Running under: macOS Sequoia 15.3.2
Matrix products: default
BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libRlapack.dylib; LAPACK version 3.12.1
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
time zone: America/New_York
tzcode source: internal
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] PerformanceAnalytics_2.0.8 quantmod_0.4.28
[3] TTR_0.24.4 xts_0.14.1
[5] zoo_1.8-15 tidyquant_1.0.11
[7] lubridate_1.9.4 forcats_1.0.1
[9] stringr_1.6.0 dplyr_1.1.4
[11] purrr_1.2.0 readr_2.1.6
[13] tidyr_1.3.2 tibble_3.3.0
[15] ggplot2_4.0.1 tidyverse_2.0.0
[17] readxl_1.4.5
loaded via a namespace (and not attached):
[1] RobStatTM_1.0.11 generics_0.1.4 stringi_1.8.7 lattice_0.22-7
[5] hms_1.1.4 digest_0.6.39 magrittr_2.0.4 evaluate_1.0.5
[9] grid_4.5.2 timechange_0.3.0 RColorBrewer_1.1-3 fastmap_1.2.0
[13] cellranger_1.1.0 jsonlite_2.0.0 scales_1.4.0 cli_3.6.5
[17] rlang_1.1.6 withr_3.0.2 yaml_2.3.12 otel_0.2.0
[21] tools_4.5.2 tzdb_0.5.0 curl_7.0.0 vctrs_0.6.5
[25] R6_2.6.1 lifecycle_1.0.4 htmlwidgets_1.6.4 pkgconfig_2.0.3
[29] pillar_1.11.1 gtable_0.3.6 glue_1.8.0 xfun_0.55
[33] tidyselect_1.2.1 rstudioapi_0.17.1 knitr_1.51 farver_2.1.2
[37] htmltools_0.5.9 labeling_0.4.3 rmarkdown_2.30 compiler_4.5.2
[41] S7_0.2.1 quadprog_1.5-8