Sign In
City of Philadelphia

Watershed Protection

How We Protect Philadelphia

In addition to protecting Philadelphia’s waterways with Water Pollution Control Plants and other infrastructure, the Philadelphia Water Department (PWD) defends our rivers from threats and pollution sources locally and beyond the City limits to ensure safe, high-quality drinking water and healthy local waterways.

Our Watershed Protection Program uses a multi-barrier approach that includes emergency preparedness systems, public and private communication networks, computer modeling systems, laboratories, regional and national partnerships, and the development and implementation of formal plans that guide watershed protection efforts and infrastructure investment.

Our Source Water Protection Plans, based on rigorous Source Water Assessment reports, guide stewardship of the Schuylkill and Delaware River watersheds, the source of drinking water for Philadelphia’s 1.5 million residents and millions living outside the city.

Through developing the Source Water Protection Plans, we identified and prioritized potential and existing sources of pollution within the 10,000-square-mile upstream area that encompasses the watersheds supplying our drinking water.

This knowledge allows us to plan for potential events that may impact drinking water quality.

Here, you will find details about the technology, planning, partnerships, and public communication tools we use to protect drinking water on a watershed-wide scale.

Preparedness Systems and Monitoring

Delaware Valley Early Warning System

The Delaware Valley Early Warning System (EWS) is a private, web-based emergency communication system created to protect our drinking water by providing rapid notification to subscribers in the lower Delaware River watershed following events that could impact water quality. More than 300 subscribers, representing 50 organizations, currently use the Early Warning System. Users include representatives from public and private drinking water utilities, industries withdrawing water from the Schuylkill and Delaware Rivers, and representatives of government agencies. The U.S. Environmental Protection Agency and Pennsylvania Department of Environmental Protection (Pa. DEP) provided initial funding in 2002, and EWS went online in 2004.

EWS components include:

  • Computer telephony
  • Advanced GIS functionality
  • Remote data collection and transmittal equipment
  • Data loggers [Data-logging device network]
  • Fully automated integration with commercial emergency mass notification systems Enterprise-level email servers
  • Website security infrastructure
  • Non-tidal and tidal time-of-travel models
  • Plume time-of-travel models
  • Data warehouse with user-friendly search functions

Since 2005, over 300 events have been reported through EWS, including chemical and fuel spills, water main breaks, sewage bypass flows and spills, pesticide spraying, and truck and train freight accidents.

Water Resources Modeling

Identifying, characterizing, and prioritizing potential risks to the water supply.

River and Reservoir Modeling

Philadelphia’s drinking water supply is supported by seven upstream reservoirs. Operational Analysis and Simulation of Integrated Systems (OASIS) software assists the department in simulating watershed management policy alternatives in the Schuylkill and Delaware River watersheds, which includes all tributary streams and reservoirs.

This water supply modeling technique allows the department to compare current and alternative policies regarding reservoir storage availability and related streamflow levels during seasonally wet and dry conditions, moderate to severe drought conditions, and water emergencies.OASIS software allows for the proactive analysis and design of watershed management policies that dictate the extent to which upstream reservoir releases are capable of maintaining the water quality and quantity of the Philadelphia drinking water supply.

Cross-Channel Transport Model

The cross-channel transport model is used to predict the risk of contaminants from the New Jersey side of the Delaware River potentially reaching the department’s Baxter Water Treatment Plant intake, located in Philadelphia, by traveling with sub-tidal water currents across the channel. This is a valuable tool for evaluating contamination risk and responding to emergency situations.

In November 2012, a vinyl chloride spill on Mantua Creek in Paulsboro, N.J., was reported by the Early Warning System. The cross-channel transport model was successfully used to predict that tidal movement and sub-tidal currents would not transport the contaminant across the channel and upstream to the Baxter intake, avoiding potential contamination or a costly preventive shutdown.

Tidal Spill Trajectory Tool

In order to calculate the time of travel from a spill event to an intake located in the tidal portion of the Delaware River, the Delaware Valley Early Warning System was upgraded with the support of the Delaware Bay Area Maritime Port Security Grant Program to include the Tidal Spill Trajectory Tool in 2014.

The Tidal Spill Trajectory Tool can predict the movement of chemical, biological and radiological contaminants discharged into the tidal Delaware River in the event of an accidental or deliberate contamination incident.

This tool incorporates the effect of wind and weather factors in calculating the movement of water pollution in a tidal setting. The model projects a spill path and reports arrival times for the contaminant at specific water intakes and facilities. The tidal spill path, generated from this advanced modeling application, is displayed in an animation on the EWS website and is available to subscribers in real-time-mode. A planning-mode version is currently in development to further assist subscribers in their emergency preparations in the tidal Delaware River.

Bacteria and Dissolved Oxygen Modeling

The Philadelphia Water Department constructed and validated a series of models that simulate bacteria and dissolved oxygen in Philadelphia waterways, as required by regulatory agencies overseeing the City’s Green City, Clean Waters program.

Models of the non-tidal tributaries receiving combined sewer overflows within Philadelphia are developed, as well as the tidal Schuylkill River and the Delaware River between Trenton, N.J. and Delaware City, Delaware. The Delaware River is simulated beyond City of Philadelphia boundaries in order to capture the complex relationships between tidal mixing, streamflow and urban runoff that influence water quality. Multiple software programs, including Environmental Fluid Dynamics Code (EFDC), Stormwater Management Model version 5 (SWMM5), and Water Quality Analysis Simulation Program (WASP) are used.

Salinity Modeling

The development of advanced bacteria and dissolved oxygen modeling capabilities also allowed the department to model salinity (salt levels) in the tidal Delaware Estuary.

The Environmental Fluid Dynamics Code (EFDC) software utilized by department scientists to study water quality in the tidal Delaware River is also capable of simulating salinity intrusion. Salinity intrusion is a critical drinking water supply threat that is closely monitored and managed by a series of reservoir releases, as stipulated in the Flexible Flow Management Plan and the Delaware River Basin Commission Water Code.

Salinity intrusion is a hydrodynamic phenomenon where ocean salinity from the Delaware Bay moves upstream. This can occur during periods of reduced streamflow caused by severe drought or, potentially, due to climate change-related sea level rise. The department works with regional partners to prevent salinity intrusion from reaching drinking water intakes and is investing significant resources to study salinity intrusion and the effects of sea level rise on drinking water supply quality and long-term infrastructure viability. EFDC software is an important tool in this understanding this issue.

Data Analysis and Collection

Bureau of Laboratory Services [MH3]

The Philadelphia Water Department’s Bureau of Laboratory Services (BLS) is a critical internal partner working to support Watershed Protection Program efforts.

The department’s BLS unit operates a state-of-the-art laboratory that performs a variety of water quality analyses on samples collected from the water supply, drinking water treatment plants, distribution system and wastewater treatment plants. The Watershed Protection Program and BLS work together to perform data collection, analysis and discussion of research observations.

Since 2011, BLS has been a member of EPA’s Emergency Response Laboratory Network (ERLN) and Water Laboratory Alliance (WLA). The ERLN is a laboratory network established to address a wide variety of environmental emergency scenarios. WLA is specifically focused on emergency incidents related to water. BLS is comprised of several specialized laboratories:

  • Organics Laboratory: analyzes for different classes of organic compounds
  • Inorganics Laboratory: analyzes for a full suite of general water quality parameters, plus trace metals and nutrients
  • Aquatic Biology Laboratory: expertise in microbiology, biology, and algae
  • Materials Engineering Laboratory and Materials Analysis Section: expertise in performing quality testing of materials used in Philadelphia Water Department infrastructure
  • Quality Assurance Unit: ensures the proper execution of analytical methods and accuracy of results
  • Watershed Team: responds incidents such as fish kills and conducts evaluations of the water quality and ecological conditions in the watershed

Philadelphia Water Resources Cooperative

As an integrated drinking water and wastewater utility, we use online water quality monitoring data to ensure Safe Drinking Water Act and Clean Water Act objectives.

The department works cooperatively with the U.S. Geological Survey to maintain an extensive stream gauge monitoring network within Philadelphia to characterize water quality across the city. Strategically positioned streamflow monitoring gauges are augmented with additional monitoring instrumentation to characterize the quality of water entering and exiting Philadelphia watersheds.

Near real-time results are geospatially displayed on a publicly accessible website where a traffic light-style code is used to indicate  good  (green),  undesirable  (yellow), or  poor  (red) measurements, based on Pennsylvania regulations corresponding to each tributaries' existing or designated use.

Data collected from these stations are rigorously reviewed for accuracy and added to an extensive database of continuous streamflow and water chemistry records. These records are regularly utilized by our scientists, engineers, and planners in a variety of applications to support decision making.

Delaware Estuary Monitoring

The Watershed Protection Program works with the Woods Hole Group, a renowned oceanographic research institution, to monitor the water quality of the Delaware Estuary. High-quality data is critical to building accurate computer models of the tidal Delaware River in the vicinity of Philadelphia. PWD computer models support analysis of stormwater management programs, wastewater treatment technology, salinity intrusion, sea level rise and climate change. The Woods Hole Group has deployed buoys in the tidal Delaware River upstream and downstream of Philadelphia to monitor the water current, water level, conductivity, water temperature, dissolved oxygen, chlorophyll and meteorological conditions. In addition to water quality monitoring, the Woods Hole Group also partners with Philadelphia to perform sediment core sampling and study nutrient dynamics.

Watershed Partnerships

Schuylkill Action Network

One of the department’s most successful partnerships, the Schuylkill Action Network (SAN), includes partners from state agencies, local watershed organizations, land conservation organizations, businesses, academics, water suppliers, local and state governments, regional agencies, and the federal government.

With the power to transcend regulatory and jurisdictional boundaries, the SAN implements protective measures throughout the Schuylkill River watershed. The SAN assists our department in eliminating illegal discharges and in identifying discharges that are in violation of permit requirements as well as releases from combined sewers and un-sewered communities. The SAN also focuses on mitigating abandoned mine drainage, reducing agricultural and stormwater runoff, supporting sustainable land use, and education and outreach.

Schuylkill River Restoration Fund

The Schuylkill River Restoration Fund (SRRF) is a public-private partnership providing grants for environmental projects that improve and protect water quality in the Schuylkill River watershed.

Our partners in funding this program include Exelon’s Limerick Generating Station, the Partnership for the Delaware Estuary, MOMs Organic Market, and Aqua Pennsylvania. The Schuylkill River Heritage Area (SRHA), managed by the nonprofit Schuylkill River Greenway National Heritage Area, administers the grant funding. Eligible recipients include organizations such as government agencies, nonprofit organizations, watershed organizations, and conservation districts.

The Philadelphia Water Department is a member of an advisory committee that carefully selects project for funding. Other committee members include representatives from Exelon, the Delaware River Basin Commission, U.S. EPA, Pa. Department of Environmental Protection, the Partnership for the Delaware Estuary, the Schuylkill River Greenway NHA, and the Schuylkill Action Network.

Located throughout the Schuylkill River watershed, these investments are improving water quality one project at a time by reducing impacts from abandoned mine drainage sites, agricultural operations and stormwater runoff.

Since the SRRF was established in 2006, over $2.7 million has been collected to fund more than 80 projects in the Schuylkill River watershed. The department highly values this unique public-private partnership as a means of implementing on-the-ground watershed protection projects that improve water quality for Philadelphia’s drinking water source.

DO Partnership

Regional environmental regulatory agencies are in the process of considering changes to water quality criteria that could impact acceptable levels of dissolved oxygen in local waterways. Dissolved oxygen, or DO, is influenced by a number of factors, including sewage discharges and the presence of excess nutrients in rivers and streams.

In response, the Philadelphia Water Department is currently developing a Dissolved Oxygen (DO) Partnership with other large regional municipal utilities to share strategic utility planning and technology evaluations.

Historical water quality improvements, especially increased levels of dissolved oxygen (DO), followed the widespread construction and operation of wastewater treatment infrastructure in the Delaware Estuary. Prior to the Clean Water Act, very low DO levels related to untreated sewage discharges and excess nutrients created infamous “dead zones,” impacting fish and other aquatic species on rivers like the Delaware.

While water quality has improved dramatically since 1950s, the Philadelphia Water Department and our partners in watershed protection continue to address targeted issues related to DO and other water quality concerns with the goal of further improving our waterways for wildlife, recreation and more.

To continue progress in reducing nutrient discharges and improving DO levels, communities operating wastewater treatment facilities in our watersheds must undergo a strategic review of infrastructure that will inform the implementation of advanced technologies and operational adjustments.

Understanding infrastructure capabilities, limitations, and affordability will be critical to further reducing pollutants in the Delaware Estuary in the future. As utilities begin lengthy, individualized planning processes, the DO Partnership will encourage sharing of findings and analyses in a way that will benefit all regional utilities working to improve water quality.

Partnership for the Delaware Estuary

A key element of the Watershed Protection Program is a watershed-wide approach to planning and analysis of the drinking water supply. The nonprofit organization Partnership for the Delaware Estuary (PDE) is critical to achieving many department initiatives outside of Philadelphia. PDE was founded with the overarching objective of working towards a cleaner and healthier Delaware River and Estuary. In support of this mission, PDE leads many water quality education and outreach campaigns and projects in collaboration with the department.

PDE has been a member of the Schuylkill Action Network (SAN) since its establishment in 2003, and continues to serve a leading role in the organization. This role includes managing the large network of partners, developing policy, partnerships and resources for SAN, promoting SAN through press releases, events and other media, and managing collaborative work-groups designed to provide targeted solutions and projects to achieve improvements in water quality.

Additionally, the partnership assists PWD in meeting Clean Water Act regulatory requirements through outreach programs that engage Philadelphia residents in the prevention of stormwater pollution impacting the Schuylkill and Delaware rivers. This partnership is critical for the continued success of the SAN and other water quality education and outreach programs throughout Philadelphia’s source watersheds.

Water Resource Association of the Delaware River Basin

The Water Resources Association of the Delaware River Basin (WRA-DRB) is a non-profit, non-partisan advocacy and public information organization comprised of industry, public and private utilities. The Philadelphia Water Department has long been a member of WRA-DRB, and highly values their efforts to organize and inform regional utility efforts to shape water resources management policy. The department plants to work closely with WRA-DRB to identify and advocate for the development and expansion of federal and state investments in drinking water and wastewater infrastructure.


Climate Change Adaptation Program

As a leader among water, wastewater and stormwater utilities, the Philadelphia Water Department employs innovative technologies, leading research, and adaptive management strategies to ensure high levels of safety and service. It is our obligation to prepare for the impacts of climate change and we are committed to working with the Office of Sustainability, other city agencies, partners, stakeholders, climate scientists, industry experts, and officials from all levels of government to address this challenge. Learn more about our Climate Change Adaptation Program.

Wastewater Master Plan

The Wastewater Master Plan (WMWP) is a project that takes into consideration existing wastewater treatment plant infrastructure capacity and conditions as well as projected capacity and regulatory and sustainability drivers in order to develop a prioritized capital improvement plan.

The first version of the WWMP, completed in 2016, is intended to be updated every five years in order to maintain the most accurate and strategic plan for investing in wastewater infrastructure. Issues explored throughout the WWMP process include regulatory and land use issues, flow projection and capacity needs, hydraulic capacity, combined sewer overflows, the Long Term Control Plan, energy self-sufficiency and management, and drivers of change such as population growth, climate change impacts, and evolving technologies. The Watershed Protection Program works closely with the teams that support the WWMP to provide insight into changes in water quality standards, water quality modeling of the receiving waters, and facilitate engagement with other regional wastewater utilities.

Water Master Plan

The Water Master Plan (WMP) is a project that reviews existing drinking water treatment, pumping, distribution, and supply infrastructure in the context of anticipated regulatory and environmental drivers. The objective of the WMP is to develop a strategic, long-term capital improvement plan that anticipates the capacity, treatment, and resiliency needs of the future. The WMP is reviewing drivers such as changing city and regional water demand, infrastructure age and condition, supply yields and quality, regulatory changes, and advanced treatment technologies. The Watershed Protection Program supports the development of the WMP by providing analysis of the Schuylkill and Delaware River drinking water supplies, including their current hydrology and water quality, as well as anticipated drivers and changes to future water quality and quantity.

Long-Term 2 Enhanced Surface Water Treatment Rule – Watershed Control Plan

The the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2) is a a source-water-based regulation created under the Safe Drinking Water Act by the U.S. EPA in 2006. LT2 strives to protect the public from waterborne-illnesses caused by Cryptosporidium and other microbial pathogens in drinking water. Public water systems are required to conduct two years of Cryptosporidium monitoring at their intake, the results of which will classify the water system into one of four categories or ‘Bins’ to determine if additional treatment credits are required.

Depending on the resulting classification, a utility can select from the additional treatment credit options provided by the EPA in the “microbial toolbox” to achieve compliance. Microbial toolbox options include source water protection and management programs, pre-filtration processes, treatment performance programs, additional filtration components, and inactivation technologies.

As a result of the first round of LT2 monitoring, the Philadelphia Water Department completed a Watershed Control Plan (WCP) for the Queen Lane intake on the Schuylkill River. The WCP identifies potential and actual sources of Cryptosporidium in the Schuylkill River watershed, discusses the effectiveness and feasibility of various control measures, establishes a set of goals for implementation, and presents a quantitative assessment of mitigation measures to be taken. The WCP focuses on three priority sources of Cryptosporidium: wastewater discharges, agricultural land use runoff, and animal vectors. PWD addresses Cryptosporidium in the watershed both by implementing Watershed Protection Program initiatives and specific structural and non-structural control measures in the Schuylkill River watershed.

In fulfillment of the WCP requirements, the department submits annual status reports and a triennial Watershed Sanitary Survey to the Pennsylvania Department of Environmental Protection. In 2018, we will complete our fifth year of the WCP and plan to continue ongoing initiatives. The Queen Lane WCP created a successful model for implementing effective Cryptosporidium control measures throughout the Schuylkill River watershed and will be expanded to include high-priority areas in the Delaware River watershed.

Public Communication


Swiftreach Swift911 is used to contact multiple customers with voice, text, or email messages. In the event of an incident such as a large water main break, we are able to isolate the service area that may experience temporarily reduced water pressure and notify them about the break and repair timeline.

Philly RiverCast and CSOCast

The Philadelphia Water Department manages and operates two public water quality notification websites, Philly RiverCast and CSOCast. Precipitation is a trigger for declining water quality in the creeks and river sections covered by RiverCast and CSOCast. RiverCast forecasts potential pathogen concentrations in the Schuylkill River between Flat Rock Dam and Fairmount Dam.

RiverCast, often used by Philadelphia’s competitive rowing community and other recreational users, displays one of three ratings (green, yellow, red) to communicate whether water quality is prohibitive of direct contact with the river. A “red” rating is associated with the highest risk of contact with illness-causing bacteria and pathogens, while a “green” rating indicates that predicted bacteria levels are low and water quality is suitable for all activities.

CSOCast uses a similar three-color system to alert the public to combined sewer overflows (CSOs), during which water quality is also prohibitive of recreation. More information is available at and the CSOCast link on


The Philadelphia Office of Emergency Management is a partner with the Watershed Protection Program and offers Philadelphia residents emergency information through the ReadyPhiladelphia program. Residents can sign up for text or email notifications about severe weather, mass transit delays, special events, warnings, or environmental emergencies. Customize your notifications at

Philadelphia Water Department Notifications

Members of the public can sign up for email and text notifications from the Philadelphia Water Department here.

Subscribers can choose from topics including alerts and notifications, customer assistance programs, environment and sustainability news, job opportunities, and volunteer events. In the event of a citywide water emergency, all subscribers will be notified.

We rely on residents and customers to report situations that can impact water quality and service. If you:

  • Suspect possible water contamination impacting our rivers or creeks
  • Notice taste or odor issues with your drinking water
  • See a possible water main break or other urgent infrastructure issue

Report this information immediately by calling our water emergency hotline: (215) 685-6300

Social Media and PhillyH2O Blog

In addition our City of Philadelphia website at, we maintain social media accounts to interact with our customers and other audiences, including regional partners and peer cities and utilities.

Information about new projects, ongoing projects, and general interest stories about regional waterways are shared on our blog, Facebook and Twitter accounts.