Cory L. Rhodes, Department of Earth Sciences, University of South Alabama, Mobile, AL 36688. E-Mail:

            Dog River endures constant problems, whether it is sedimentation, sewage, erosion or litter. Litter is one of the main problems causing the degradation of the Dog River watershed, destroying aquatic and botanical life as well as prohibiting the enjoyment of summertime activities. This project is an update to the 2003 paper Does ‘Only Trash Litter’? by Tammy Pounds. Similar to the 2003 paper, the current project tries to identify specific communities in the city of Mobile  (based on the 2000 United States Census) that are the primary cause of litter in the watershed based on socioeconomic factors such as educational attainment, labor force status, income, age, race and sex. To do this, litter was collected and tallied in nine communities throughout the City of Mobile which ranged from high to low income housing. After the census data was obtained and litter amounts tallied, a statistical test, Kendall’s Tau, was performed to determine any correlations between litter and the socioeconomic factors. The current project is updated from the 1990 Census to the 2000 Census, showing the changes in the census tracts between the 1990 and 2000 Census data as well as any opposing results. Results show strong indirect relationships between educational attainment, labor force status, income and litter. Slightly indirect relationships were found between race, sex and litter and a slight direct relationship was determined between age and litter. 

            Keyword: litter, socioeconomic factors, census data.



Dog River endures constant problems, whether it is sedimentation, sewage, erosion, or litter. There are numerous portions of Dog River that are relatively clean and others that are in need of care. Litter is one of the main factors causing degradation of the Dog River watershed. It not only affects the quality of the water, but also destroys aquatic and botanical life and prohibits the enjoyment of summertime activities. Sediment traps that are placed in the rivers have become clogged with debris, causing the excess litter to flow freely downstream. Without proper maintenance of these traps, litter will continue to flow downstream when water levels rise (Pounds 2003).

Litter has become a major environmental problem and, according to a Harris national poll, 94 percent of Americans believe that something should be done to curb pollution (Harper 2004).  However, “according to the EPA, the average human has doubled his production of garbage since 1960, producing 4.5 pounds a day. So it is no surprise that we have serious littering and dumping problems” (Rea 2005). Over 80% of litter found in watersheds and surrounding creeks, rivers, and streams results from debris found on land (

This raises questions about how litter enters into the watershed and, more importantly, who’s to blame.  The primary result of litter entering the watershed is excessive rainfall resulting in runoff on land. According to the Merriam-Webster Collegiate Dictionary, runoff is defined as “the portion of precipitation on land that ultimately reaches streams often with dissolved or suspended material” (1993).

Social and demographic characteristics are other extremely important factors that come into play.  Research assumes that less educated, predominantly older male adults living in areas not impacted by environmental hazards are the primary culprits for excessive littering (Harper 2004). However, this assumption is not a very powerful one. By utilizing census data, this paper will determine the socioeconomic factors that are the primary cause of litter and help educate the community on ways they can preserve the watershed.  A good understanding of watersheds will develop participatory solutions in protecting the watershed (Randhir & Cole 2005).


Research Question:

One of the main questions associated with the Dog River Watershed is “Who litters the most?”. The hypothesis that I tested tries to answer this question based on socioeconomic factors such as educational attainment, labor force status, income, age, race and sex of nine communities near Dog River. If a relationship exists between any of these factors and litter, then the hypothesis can be accepted and Dog River Clearwater Revival will be able to educate those in the community on preserving the watershed.



            To go about testing this hypothesis, I gathered the tools I needed to begin the project: I acquired a map of Mobile County with the communities designated (2000 Census Tract Map) and also acquired statistical census tract data from the United States Census Bureau on basic socioeconomic factors in nine separate communities in Mobile County (2000 U.S. Census Bureau—General Housing, Social, and Economic Characteristics for Census Tracts and Block Numbering Area). A census tract is defined as “a small, relatively permanent statistical subdivision of a county” usually consisting of a few blocks ( The nine communities I gathered my data in  (Figure 1) include neighborhoods between: Knollwood Drive and University Boulevard South (census tract/ block numbering area 37.07), Airport Boulevard and Montlimar Street (33.01), Airport Boulevard and Downtowner Boulevard (32.04), Cottage Hill Road and Michael Boulevard (32.05), Government Street and Johnston Avenue (24), McVay Drive North and Interstate 10 (22), South Broad Street and St. Francis Street (2), Arlington Street and Virginia Street (13.02), and Bayfront Road and Hannon Road (18) (United States Census Bureau 2000).

I revisited these nine communities from the original project to count, collect and tally the articles of trash I found along the street (away from commercial areas and main roads) for a length of 100 feet. I returned to the sites a week later to repeat the process and noted any decreases or increases in amount. Similar to Pounds’ paper, the data collected was then placed into an Excel table and divided into three intervals based on educational attainment (Table 1). This factor was chosen as a comparison to litter due to the fact that people in different communities have various education levels when it comes to understanding about the environment.  I then performed the Kendall’s Tau statistical test that determines whether or not a correlation (relationship) exists between two variables—one of them being litter—and a socioeconomic factor, such as age.  The socioeconomic factors I utilized included: educational attainment, labor force status, income, age, race and sex. These are general characteristics that may offer evidence into who litters the most. This determined whether the trash in the nine communities—ranging from high-scale neighborhoods to low-income housing—is directly or indirectly related to the socioeconomic factors mentioned above.

The Kendall’s Tau statistical test was chosen to be the most appropriate test in comparing individual factors against one another. This test determines a relationship between one socioeconomic factor and litter. Multiple regression is another test that can be used to perform these correlations. However, this test combines all the socioeconomic factors into one variable and compares it to litter as opposed to individually. Additionally, it is not relevant in this situation due to the low sample size.



After I gathered the data and preformed the Kendall’s Tau test, I discovered that there was a strong indirect correlation or relationship (-0.772) between educational attainment and litter (Figure 2). Other tests that include a strong indirect relationship consist of labor force status and litter (-0.772 correlation) (Figure 3) as well as income and litter with a -0.5 correlation (Figure 4).

            There is a slight indirect relationship between percent white and litter (-0.167) (Figure 5) and percent female and litter (-0.167) (Figure 6). However, there is a slight direct relationship between age and litter with a result of 0.090 (Figure 7).


Discussion and Conclusion:

The statistically insignificant data includes age, race and sex. In other words, these socioeconomic factors have no effect on littering amounts in a particular area.  The statistically significant factors include educational attainment, labor force status and income. These factors do have an effect on litter in the environment. Therefore, the hypothesis can be accepted, claiming that there is a relationship between educational attainment, labor force status, and socioeconomic status and the amount of litter entering the Dog River watershed.

There are differences between a few of the socioeconomic factors and litter within the original and current projects. These include significance differences between race and labor force status and litter. Pounds’ project showed statistically significant data results between race and litter while the current study shows a statistically insignificant result between the two. Inversely, labor force is shown to be statistically insignificant within Pounds’ project while the current study shows this socioeconomic factor to be statistically significant with litter.

There are numerous plausible reasons why there are significance differences within these two socioeconomic factors. One could be that more Caucasians (as opposed to African Americans) completed the 2000 United States Census within a particular community or communities as opposed to the 1990 United States Census. This would result in a lower level of probability (lower level of significance) within the Kendall’s Tau ranking, allowing the outcome to be statistically insignificant. Perhaps another reason would be that more persons within a particular community entered into the civilian labor force between 1990 and 2000, allowing the level of significance to increase therefore resulting in a statistically significant data set.  

The current project shows statistically significant relationship between educational attainment and income and litter. A reason for this may be that some of the communities comprising low educational attainment cannot afford proper resources in order to clean litter and debris from neighborhood streets and walkways. As stated in Pounds’ discussion, those neighborhoods that contain higher amounts of educated peoples and incomes can afford maintenance crews for litter pickup and are aware of the consequences that litter has on the environment (2003). However, based on the data from the 2000 Census, the majority of persons who completed the form were of relatively low educational attainment and income therefore resulting in the insignificant statistical relationships.

The data and results gathered from this project would allow Dog River Clearwater Revival to target all census tracts (not just the ones studied) in relation to the Dog River watershed and extrapolate ways in which the watershed can be preserved. Programs can be provided to the general public as well as schools within the area to educate those on proper watershed protection and preservation.


References Cited:

Federal Financial Institutuion Examination Council (FFIEC). Home Mortgage Disclosure Act.  HMDA Glossary.


Harper, Charles L. (2004). “Environment and Society: Human Perspectives on Environmental Issues”. Third Edition. Que Corporation, 391.


 “Littering Is Throwing It All Away”. Watershed Watch. <>.


Merriam-Webster Collegiate Dictionary. 10th edition. (1993). Merriam-Webster, Incorporated.


“Mobile County, Alabama”. Reference Maps. United States Census Bureau. American Factfinder (2000). <>.


Pounds, Tammy. (2003). Does “Only Trash Litter”? <>.


Randhir, Timothy & Genge, Cole. (2005, Apr. ).  Watershed Based, Institutional Approach to Developing Clean Water Resources. Journal of the American Water Resources Association, 41, 2, 413-424.


Rea, Kimberly. (2005, Sept. ). “Trash nation: learn how to prevent your public lands from being trashed”. Parks and Recreation.