United By Blue is a wonderful local Philadelphia company that is working hard to cleanup creek – river trash. Bartram’s Garden, along the Schuylkill River, has been one of their cleanup sites so I decided to check out the bank trash for myself.
I 1st visited Bartram’s on 8/10 and made a repeat visit on 9/3. Here is a slide show of my bank trash findings along the Bartram’s Garden’s 3,000 foot stretch of tidal Schuylkill River bank. (Click any slide to start show. Press x in upper left corner to return to post)
Yes Philadelphia, in addition to the Tacony-Frankford Creek, we have a Schuylkill River trash problem. Plastic bottle-food wrappers-food container litter is being carried to the River by run-off during rain storms upstream of Philadelphia and in the City.
Our plastic trash is building up on our shore lines and in the N Atlantic gyre.
Plastic street litter is a serious water pollution problem that we must through product controls, litter prevention, street cleaning and waterway cleanups. Right now we are losing the fight against marine debris.
Have you ever wondered why the Wissahickon Creek is so clan and the Tacony Creek is so dirty?
After conducting numerous field surveys, I’m beginning to understand the Tookany – Tacony Creek trash situation. I’ve found 10 Philadelphia Water Department stormwater outfalls with evidence of trash in the outfall channel or immediately downstream of the outfall, making hte outfall a suspect for trash discharge to the Tookany – Tacony Creek.
This pdf documents my concerns about the discharge of floatable trash from PWD outfalls: Potential_role_of_10_outfalls
There are approximately 300 outfalls that discharge stormwater to the Tookany – Tacony – Frankford Creeks. Litter from streets, parking lots and illegal dumps is carried to the Creeks by run-off during/ after rain storms.
This slide shows takes you on a tour of 10 Philadelphia Water Department stormwater outfalls that carry Philadelphia litter to the Creeks.
Tookany Creek, Tacony Creek in Philadelphia, has both flooding and creek trash problems that affect Cheltenham and Philadelphia residents. I have written about the Tookany -Tacony Creek trash problems here, here, here and here.
Today, I am starting a series on the Tookany Creek flooding situation to address 2 keys questions:
Is global warming changing precipitation patterns in the Philadelphia area
What are Tookany Creek flood flow trends
This post discusses Philadelphia area precipitation trends to address the question on how perceived increases in rainfall intensity may be affecting flooding in Cheltenham Township. A later post will review the Creek flow data.
Rainfall Data at Philadelphia International Airport (KPHL)
Daily rainfall data dating back to 1874 is available at the Phillyweather.net site where users can download an Excel workbook with daily data (link). I used the Phillyweather.net data to evaluate changes in precipitation patterns. Here is what I found:
Frequency of high intensity rain storms has increased since 1960. There were only two 4-inch or more rain storm events in the 86 year period 1874-1959, compared to 12 storm events in the 52 year period 1960-2012.
The calculated 100 year return period daily precipitation in the 1874-1959 period was 5.11 inches, that value increased to 6.86 inches in the 1960-2012 period.
9 of top 10 rain storms in the 1874-2012 period occurred since 1960
Details
Most people have heard about the “100 year storm“. It is actually the storm that has a 1% chance of occurring in a given year. The figure bellow shows how we can use precipitation frequency analysis to estimate the the 100 year storm for Philadelphia International Airport. Tthe plot shows the peak rain storm in inches per day for each year from 187 4 to 2012 plotted on a Gumbel probability grid (link). This allows us to identify the rainfall for any return period, say 10 years or 100 years.
The estimated storm 100-year return period, isng the entire 1874-2012 data period is 5.83 inches. Since we know that rain intensity has been changing, I’ve also calculated the 100 year storm estimates for the pre-1960 and post 1960 periods, as shown in this 2nd chart.
The calculated 100 year storm is affected by the period included in the precipitation frequency analysis. If we just consider the 1874 to 1959 period, we get a 100 year return period storm of 5.11 inches. If we include just the 1960 to 2021, we get 6.86 inches. Clearly we are seeing higher intensity storms since the 1960s.
NOAA, using more sophisticated techniques, estimates the Philadelphia Airport 100 year – 24 hour storm to be 7.72 inches (link). Since the maximum 1874-2012 24 hour rain was 6.83 inches, Philadelphia Airport has not seen the NOAA 100 year storm yet.
Perspective on Variation in Rainfall Across our Region
This NOAA map shows the 100 year return period rain for the mid-Atlantic region, including Pennsylvania, Delaware and New jersey. Notice the green – yellow areas in western Pa and the purple areas in Delaware and New jersey. The green – yellow ares have estimated 100 year storms of 5 – 6 inches while the purple areas have storms of 10 – 11 inches. The Philadelphia area is right in the middle at 7.01 – 8 inches.
The next post will discuss Creek flow data from the USGS gaging station at Adams Avenue.
Do you have data related questions about rainfall and creek flow? If you do, let me know and I’ll see what I can do. Just click in the the Reply box and submit your question/ comment.
Upper Rock Creek is a tributary of the Tookany Creek that carries stream flow from the Creek headwaters, including Cedarbrook Plaza and Cheltenham Mall parking lots and businesses along W Cheltenham Ave and Ogontz Ave. During rain storm events, stormwater runoff carries parking lot and street litter and debris into the Upper Rock Creek.
Some of this stream trash is deposited along the Upper Rock Creek bed and banks; the rest is carried downstream to the Tookany, Tacony and Frankford Creeks, the Delaware Bay and the Atlantic Ocean.
Here is a Google Map that shows the Upper Rock Creek survey limits as well as the entire Tookany Creek , and its tributaries, including Rock Creek, Baeder Creek and Jenkintown Creek.
This map shows the photo locations for the Cedarbrook Plaza and Cheltenham Mall parking lot litter photo survey and limited survey of stream trash in the Upper Rock Creek.
The following 5 photos show litter and debris around the Cedarbrook Plaza, these photos were taken on 1/14/13.
