Traditional Infrastructure Programs

Through maintaining the City's existing traditional infrastructure, we're extending its use and increasing the efficiency of flow conveyance, storage, and treatment.

Inlet Cleaning

The Inlet Cleaning Unit is responsible for the inspection and cleaning of approximately 79,159 stormwater inlets throughout the City of Philadelphia. The group is responsible for retrieving and installing inlet covers, replacing missing covers, installing locking covers, and unclogging choked inlet traps and outlet pipes. This program also helps alleviate street flooding when hydrants are open, water mains break, and rain storms overburden the sewer system's capacity.

Combined Sewer Overflow (CSO) Regulator Inspection & Maintenance

The Flow Control unit is responsible for the operations, maintenance, inspections and cleaning of 175 combined sewer-regulating chambers, 89 tide gate chambers, 26 storm relief chambers, various siphons and related wastewater control devices.

Inspection and maintenance of the regulating chambers and tide gates are performed since operational malfunctions of the regulators and tide gates could cause a dry weather discharge. Dry weather discharges are a violation of regulatory requirements and can also have a major impact on stream water quality. Combined sewer-regulating chambers inspections and clearing of any blockages prior to causing a dry weather discharge are a priority. Many of the discharges that do occur are a result of debris such as rags, sticks and other debris accumulating after large storms.

Defective Lateral Detection & Abatement

Due to problems generally attributed to improper installation or lack of oversight during construction, sanitary wastewater from some properties can be transported into the storm sewers and from there, to the streams and rivers. This intrusion of sanitary wastewater causes pollution of the streams and rivers, which are the source of city’s water supply. The polluted streams and rivers also endanger the physical health and safety of residents and users of the streams. PWD works to identify and abate the plumbing connections (defective laterals) that cause the sanitary wastewater to drain into the streams.

Sewer Assessment(CCTV Technical Inspections)

PWD has implemented a comprehensive Sewer Assessment Program to provide for continued inspection and maintenance of the collection system using closed circuit television. The SAP is being used to guide the capital improvement program to ensure that the existing sewer systems are adequately maintained, rehabilitated, and reconstructed. The CCTV Technical Inspections has several functions which include the inspection of sewers turned in for sewer complaints, special inspection requests from the Water / Sewer Design group and the post construction inspection program. They also work with the Defective Connections group in the identification of defective lateral connections.

Sewer Maintenance

The Sewer Maintenance unit is responsible for operation and maintenance of the city’s sanitary, storm, and combined sewer systems. Included in these systems are all related structures such as branch, interceptor, and main sewers; stormwater inlets and laterals; and manholes. The majority of work consists of flushing and cleaning sewers using high pressure and vacuum equipped trucks, excavations and point repairs to sewers, inlet resets and repairs, and examinations of sewers.

When they can not be prevented, PWD responds to blockages and dry weather discharges. Random dry weather discharges can occur at virtually any CSO outfall following sudden clogging by unusual debris in the sewer, structural failure of the regulator, or hydraulic overloading by an unusual discharge of flow by a combined sewer system user. Random dry weather discharges are promptly eliminated by cleaning repair, and/or identification and elimination of any excessive flow and/or debris sources. Regular and reactive inspections and maintenance of the CSO regulators are performed throughout the City. These programs ensure that sediment accumulations and/or blockages are identified and corrected immediately to avoid dry weather overflows. The CSO maintenance group utilizes the remote monitoring network system daily as a tool to help identify the locations that are showing abnormal flow patterns. By using the system in this manner the crews are able to correct many partial blockages before they become a dry weather discharge.

Hydraulic and Hydrologic Modeling

Hydrology is the study of the movement, distribution and quality of water. A hydrologic model predicts the path water takes after it falls in the form of precipitation. The model performs a step by step accounting of rainfall, snowmelt, infiltration, surface detention, overland flow, channel flow, and water quality constituents leading to the calculation of one or more hydrographs and/or pollutagraphs at a certain geographic point such as a sewer inlet.

A Hydraulic model simulates hydraulic flow routing for open channel and/or closed conduit systems. This model recieve hydrograph inputs at specific nodal locations such as in inlet or manhole. The model performs dynamic routing of stormwater and wastewater flows through drainage systems and receiving streams.

H&H modeling is used to make predictions about the response of natural waterways and the PWD sewer system to rainfall. A hydraulic and hydrologic model is an estimate of actual conditions. The model is calibrated to real data to achieve a high level of accuracy; however it should be understood that a certain level of error will always be present.

Pumping Station Maintenance

PWD has a Wastewater Pumping Station Maintenance Group that are responsible for the operations and maintenance of 17 wastewater pumping stations, 3 stormwater pumping stations and 2 sodium hypochlorite dosing stations and 8 computer controlled CSO regulators.

Comprehensive Geographic Information System (GIS) of the City Sewer System

The Philadelphia Water Department completed, in 2005, a data conversion project that resulted in the creation of GIS coverages for all of the city’s water, sewer, and high pressure fire infrastructure. The conversion project consisted of extracting data from over 250,000 engineering documents that exist in digital format and have been indexed by location.

Rain Data Collection

A rain gauge, otherwise known as anudometer or a pluviometer, is a type of instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a set period of time. The data gathered is often utilized to inform the Hydrologic and Hydraulic Modeling efforts.

Real Time Control

Real time control is a dynamic method we use to smarten our infrastructure systems. A computer controller is programmed to analyze measured or predicted values of flow depth and velocity to determine optimal operation. A typical example involves regulating structures; they monitor depth of water in the sewer and mechanically control the openings on the additional pipes to minimize overflow while protecting upstream areas against flooding.

Catch Basin Controls and Cleaning

Installed as part of a stormwater inlet, catch basins are an important line of defense in separating trash and pollutants from stormwater before it enters the sewer system. Anything matter heavy enough to fall – such as pet waste, sediment, etc. – is trapped in a catch basin while water can continue through.

Stormwater Inlet Stenciling

This program seeks to curb stormwater pollution through hands-on service learning techniques for all stakeholders in the community. Stormwater inlet stenciling is the act of labeling storm drain inlets with messages that remind people not to dump anything into the storm drain, as they convey untreated stormwater and trash directly to our waterways.

Stormwater Inlet Stenciling, Philadelphia, PA