Combined Sewer Overflow, or CSO, discharges stormwater and sewage into the creek during rainfall events

The most pressing water quality problem with the potential to cause human health problems is microbial contamination from improperly managed human wastewater, says the Regional Cooperation for Water Quality Improvement in Southwestern Pennsylvania Report from the National Academies' National Research Council. In the region's main rivers -- the Allegheny, Monongahela, and Ohio -- stormwater and sewer overflows during wet weather appear to be the major contributors. In many tributaries, microbial water quality does not meet standards even in dry weather, the report adds, which suggests contamination from failing septic systems. Livestock management practices in rural areas are likely adding pathogens to streams as well, though scarce data made it impossible to determine how much, the committee said. 

A pervasive lack of adequate data hampered the committee's ability to fully evaluate and prioritize the region's water quality problems and their adverse effects, the report says.

As a first step toward improving its waters, southwestern Pennsylvania should improve the use of its existing infrastructure. To this end, the committee strongly recommended that all of the watershed's wastewater collection systems comply with EPA's Capacity, Management, Operations, and Maintenance (CMOM) policy or a similar program.

Currently only three small sub-basins within the lower Chartiers watershed are in compliance, as the map to the left illustrates.  Sewage was identified by the River's Conservation Plan (RCP) as one of the main issues facing stakeholders in the lower watershed.

The Allegheny County Sanitary Authority (ALCOSAN), which is largely responsible for managing wastewater for the City of Pittsburgh and 82 surrounding communities, should re-evaluate its draft long-term plan for controlling sewage and stormwater overflows, in light of the recently completed municipal consent orders initiated by EPA to enforce compliance with the Clean Water Act; ongoing negotiations regarding an ALCOSAN consent decree; compliance with CMOM; and information from Three Rivers "Comprehensive Watershed Assessment and Response Plan" as it is developed in the future. The CWARP framework is recommended for the development of ALCOSAN's final control plan and similar documents because of the data limitations and technical and institutional complexities that exist in southwestern Pennsylvania, the committee said. Furthermore, ALCOSAN and other wastewater treatment providers should investigate decentralized and innovative alternatives such as storing and treating overflows at remote locations or in nearby abandoned mines -- as is currently being evaluated by the Township of Upper St. Clair. A first step toward any of these options would be development of a system for real-time control of overflows -- a method that uses software to monitor, model, and manage flows.

Stream Daylighting

Removing streams from combined sewers is a high priority. In wet weather, these streams swell with runoff, enter the combined sewer systems and greatly reduce the sewers’ capacities to convey sanitary sewage, resulting in combined sewage overflows discharging directly into local streams. Currently in Sheraden Park, there is a clean, surface stream that emanates from a wooded hillside, flows for 300 feet, then drops into a combined sewer, and goes to ALCOSAN for unnecessary treatment. This project demonstrates how one stream can be separated from a combined sewer and restored with ecological sensitivity to the surface of a city park. This Stream Daylighting Project can be a highly visible regional and national demonstration project.

Alcosan has undertaken a Preliminary Design that will bring the project to 30% completion. They have selected an engineering firm (Michael Baker) and a restoration firm (Biohabitats) to begin this work. A project of this magnitude has many re-engineering considerations and stakeholders, not the least of which are the people who live in the vicinity of the park and use its ballfields, tennis courts, playground, and public pool.   Public discourse solicited residents’ input to hear their voices in this restoration process.

Fecal Coliform Water Monitoring

Chartiers is a year-round navigable waterway - a recreational creek that supports boating, fishing and hiking. These activities pose the possibility of incidental contact with the water -  hands in the water, handling fish or wet gear, accidental dunking or handling debris. Wading during the heat of summer brings deliberate contact and a greater risk of microbe ingestion.

Microbes & bigger stuff: cleaning up during a canoe ride

Sewage in the water is the main deterrent to recreational boating in the lower Chartiers Creek.  For a couple years beginning in 2001, avid outdoorsman John Hamm collected monthly water samples from Chartiers Creek at the Chestnut Street Bridge (C35 ALCOSAN outfall) in Carnegie and at the “little” Thornburg bridge (C20), just upstream from the “big” Thornburg Bridge/Rt 60.  Occasional samples have also have taken  from tributaries, storm drains and other outfalls. 

The samples were tested by US Filter labs for fecal coliform bacteria, which is a broad indicator of sewage presence, because it is a bacteria found in the intestines of mammals. Yes, that includes dogs and cats, raccoons and deer and turkey, humans and wildlife and people dumping pet duty. 

The standard which state and health agencies use for issuing the wet weather river advisories for recreational users of our large rivers, is usually 400 col/100ml (colonies of fecal coliform per 100 milliliter).. This applies to any undesignated swimming areas, such as Chartiers Creek and Pittsburgh's three rivers. State Parks and regulated lakes and ponds designated for public swimming use 200 col/100ml during the warm season. Using the 400 standard, a quick check of the data shows that half the time, coliform counts are above the standard, regardless of high or low creek levels at the time any sample was taken. 

Publicizing fecal coliform testing advises the public of health risks. The results have generated increased awareness which has led to a successful lawsuit by the Pennsylvania Environmental Defense Fund against local municipalities with sanitary sewer outfalls (SSO's), requiring them to clean up their act.

So how do you know when or not you should chance exposure? If it has rained in the last couple of days and the water is dirty-looking, then it is. Country streams in the upper Chartiers watershed may not be much better after a rain, especially if there are some of those sited septic systems, 50% of which are not effective or properly properly maintained. Not only do you have some illegal and permitted sewage discharges after hard rains, you also have a ‘flushing’ of the landscape along with everything you can imagine that is deposited on streets, parking lots, roofs, and woods and soil. Whether it is water soluble or floats on top like engine oil, rain will carry it in storm-sewers and gullies to the creek. The harder and longer the rain is, the better the ‘flush’. For public health sake, we need to know and we need to advise others

What lurks in the flow?