Handout 4: PWD System, Programs and Services Overview

Transcription

1 Handout 4: PWD System, Programs and Services Overview PWD Mission The purpose of this handout is to describe Philadelphia s drinking water, sanitary sewer and storm sewer infrastructure and the Philadelphia Water Department s programs and services to provide clean water. The Philadelphia Water Department (PWD) serves the City of Philadelphia and the region through the provision of integrated water, wastewater, and stormwater services. The utility's primary mission is to plan for, operate, and maintain both the infrastructure and the organization necessary to supply high quality drinking water, to provide a reliable water supply for all household, commercial, and community needs, and to sustain and enhance the region's watersheds and quality of life by managing wastewater and stormwater effectively. Whether we are providing safe water for residents to drink, supplying water for industries to manufacture goods here in the City, or protecting the region's water resources, serving our customers with quality has been a commitment of the Philadelphia Water Department throughout our nearly 200 year history. PWD works around the clock to ensure that a safe, high quality supply of water is always on tap, that stormwater drains away without major flooding, and that our rivers and streams become cleaner with each passing year. Our commitment to providing a safe and abundant supply of water is our commitment to all of our customers, large and small. Our commitment to collecting stormwater and treating wastewater is how we protect the health and vitality of the Delaware and Schuylkill Rivers, countless creeks and streams, and the people of our region who enjoy and depend on these waterways. Whether we are delivering safe, clean water wherever and whenever our customers need it or returning water to nature in a neverending cycle, quality is a principle that runs throughout the Philadelphia Water Department. The Water System The Water System provides water to the City, which comprises approximately a 130 square mile service area. In addition, the Water Department has contracted to provide up to 35 million gallons per day (MGD) of water to Bucks County Water and Sewer Authority pursuant to an agreement with that authority. The population served by the Water System is approximately 1,738,006, of which 1,526,000 are in the City. PWD obtains approximately 58% of its water from the Delaware River and the balance from the Schuylkill River. The City has been historically authorized by applicable regulatory authorities to withdraw up to 390 MGD from the Delaware River and up to 258 MGD from the Schuylkill River. Water treatment is provided by the Samuel S. Baxter Plant on the Delaware River and by the Belmont and Queen Lane Plants on the Schuylkill River. The combined rated capacity of these plants under the Water Department s Partnership for Safe Water procedures is 546 MGD, and their combined maximum capacity is 683 MGD. The storage capacity for treated and untreated water in the combined plant and distribution system totals 1,065.4 MG. Philadelphia has over 3,000 miles of water mains. See figure 1 at the back of this handout for locations of PWD water treatment plants and figure 2 for locations of pumping stations that distribute water from those plants. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 1 1

2 The Wastewater System The Wastewater System service area totals 360 square miles, of which 130 square miles are in the City and 230 square miles are in suburban areas. Service to suburban areas is provided under agreements with adjacent municipalities and municipal authorities, which generally require delivery of wastewater to the Wastewater System. The population served by the Wastewater System is approximately 2,276,000, of which 1,518,000 are in the City and 700,000 are in the suburbs. The Wastewater System consists of three water pollution control plants (WPCPs), 21 pumping stations, approximately 3,663 miles of sewers, and a centralized biosolids handling facility. The Wastewater System includes 1,827 miles of combined sewers, 749 miles of sanitary sewers and 720 miles of stormwater sewers. See figure 3 for locations of the Philadelphia WPCPs and figure 4 for locations of the pumping stations that feed these WPCPs. The three WPCPs processed an average of MGD of wastewater in Fiscal Year 2010 and have a combined average daily design capacity of 522 MGD. The Wastewater System is divided into three drainage districts: Northeast, Southeast and Southwest. In addition, the wastewater collection system includes 175 combined sewer overflow (CSO) regulating chambers, 164 CSO outfalls, and more than 450 stormwater outfalls. The 1972 amendments to the federal Water Pollution Control Act, known as the Clean Water Act, provide for the restoration and maintenance of the chemical, physical and biological integrity of the nation s waters. To that end, the Clean Water Act establishes the National Pollution Discharge Elimination System (NPDES), a permit system administered by the EPA in conjunction with the states. The EPA has delegated the NPDES program for the Commonwealth to the Pennsylvania Department of Environmental Protection (PADEP). The Water Department is subject to the requirements of the Clean Water Act and the conditions set forth in the NPDES permit applicable to each of the WPCPs. In addition, the City is subject to regulation by PADEP, which exercises regulatory authority over municipal sewage treatment operations, and to regulation by the Delaware River Basin Commission (DRBC), which exercises regulatory authority over withdrawals from and discharges into the Delaware and Schuylkill Rivers. The current NPDES permits for the Northeast, Southeast and Southwest WPCPs were issued and became effective on September 1, 2007 and are scheduled to expire on August 31, These permits with PADEP provide flexibility to treat additional flows resulting from efforts to control CSOs. These permits require the Water Department to update its Combined Sewer Overflow Long Term Control Plan and Capital Improvement Program to provide additional projects that reduce CSO frequency and volume. The update to the Long Term Control Plan was submitted, as required, by September 1, The PWD is currently in negotiations with the PADEP and the EPA to finalize the Long Term Control Plan. The Clean Water Act requires that publicly owned treatment works such as the treatment portions of the Philadelphia Wastewater System achieve levels of secondary treatment as defined in the Clean Water Act, or, where applicable, more stringent levels of treatment required to meet water quality standards established pursuant to any Commonwealth or federal law or regulation. By the order of the DRBC issued in 1969, the City is required to achieve effluent limitations which are considered more stringent than secondary treatment levels as defined in the Clean Water Act. The three WPCPs have maintained high levels of treatment such that they have been recognized by the National Association of Clean Water Agencies (NACWA), formerly the Association of Metropolitan Sewerage Agencies (AMSA), with either Silver, Gold or Platinum awards over the past decade. PWD s three WPCPs continue to meet all permit requirements and are the recipient of NACWA Platinum awards. Such awards are granted for five or more years of perfect compliance. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 2 2

3 The Wastewater System has effectively and significantly improved the water quality of the Delaware River, thereby fostering both public and private development of the riverfront for commercial, residential and recreational uses. PWD Watershed Approach PWD is committed to a balanced "land water infrastructure" approach to achieve its watershed management goals. Where appropriate, this method includes infrastructure based approaches but focuses on implementation of a range of land based stormwater management techniques and physical reconstruction of aquatic habitats where appropriate. The ultimate goal of PWD s approach is to regain the resources in and around streams that have been lost due to urbanization, both within the City of Philadelphia and in the surrounding counties, while achieving regulatory compliance objectives in a cost effective manner. Our vision is to unite the City of Philadelphia with its water environment, creating a green legacy for future generations while incorporating a balance between ecology, economics, and equity. PWD s Green City, Clean Waters program is the philosophy of a land water infrastructure approach made real. While maintaining and upgrading one of the nation s oldest traditional infrastructure systems is an underlying principle, we are pledging our investments in greening the City as a means to provide benefits to all the residents of the City of Philadelphia while meeting ecological restoration goals. We aim to integrate water resource management into the socioeconomic fabric of the City by creating amenities for the people who live and work here. PWD s Green City, Clean Waters program integrates the management of Philadelphia s watersheds into a larger context. It is designed to provide many benefits, so that every dollar spent provides a maximum return in benefits to the public and the environment. Stormwater Management Stormwater runoff from the Philadelphia region, whether served by separate stormwater sewers or combined sewers, impairs the streams and rivers of the City. When it rains, some water is absorbed through pervious surfaces such as vegetated areas with uncompacted soil, sand, or gravel that allow the passage of water. Other water, called stormwater, flows over impervious surfaces, such as rooftops, sidewalks, and streets, that obstruct natural infiltration. In addition, stormwater runoff from other impervious surfaces, such as compacted land or vacant land that has been disturbed from its natural wooded condition, also impacts the volume of runoff in the combined sewers and the quality of surface water when directly discharged into streams and rivers. Impervious cover and runoff from vacant compacted land exacerbates the problem of stormwater when runoff flows directly into the nearest storm drain without being mitigated. If untreated before entering our waterways (including the Schuylkill and Delaware rivers, which we use as sources of drinking water), this contaminated water can have a detrimental effect on water quality. The more impervious surfaces and compacted and graded land there are in the City, the more polluted stormwater enters the sewer system, increasing the total volume of water the City's infrastructure network must handle. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 3 3

4 What is the amount of impervious cover in Philadelphia? Roughly 54% of Philadelphia is considered impervious. Impervious is defined as a surface that water cannot penetrate. Examples include traditional street paving material, roofs, sidewalks and parking lots. Why do some areas have pipes instead of open streams? Historically, creeks were present throughout most areas of Philadelphia. The creeks enabled various industries to flourish near stream banks. But as Philadelphia grew, so did the pollution. Waste and trash were disposed of directly into the creeks waste from slaughterhouses, used dye, trash, and sewage (sanitary waste). It was standard practice in the 18th and 19th centuries to use creeks as open sewers. At one point, the rivers and creeks were so filthy that they created a health hazard resulting in the deaths of thousands of Philadelphians. Creeks were also looked upon as obstacles to development, since it is impossible to construct houses, businesses and industries atop flowing streams and creeks. Disease epidemics and land development drove many miles of creeks underground into pipes. Figure 5 shows the difference between the historic and current waterways. Two Types of Stormwater Management Systems The Philadelphia wastewater collection system deals with two types of water from your house: your sanitary sewage and your stormwater. Your sanitary sewage is the wastewater from your toilets, showers, washing machine, dishwasher, etc. Your stormwater is the rainwater that is collected from your rooftop and transported via your gutters and downspouts. Additional stormwater from your property is collected in the streets via inlets or stormwater basins. Where the water goes once it leaves your property depends on which type of sewer system you are connected to separate sanitary system or combined sewer system. In Philadelphia, we have two types of sewer systems that, in total, are 3,663 miles long. In areas with combined sewers, a single pipe carries both stormwater from streets, houses, and businesses as well as wastewater from houses and businesses to a water treatment plant. In areas with separate sewers, one pipe carries stormwater to the City's streams while another carries wastewater to a water treatment plant. See figure 6 for a diagram showing the two types of systems. Combined Sewer System In combined sewered areas, traditionally the older parts of the City, there is one sewer system that collects both stormwater runoff and wastewater from homes, businesses and industries. In dry weather and during smaller storms, these combined sewers bring wastewater or the wastewater/stormwater mixture to wastewater treatment plants for treatment prior to discharge of treated effluent into the waterbodies. The combined sewer system covers about 60% of the sewer service area in Philadelphia. Serving more than three quarters of the City's residents, the combined sewer system is in the oldest and densest parts of the city, including Center City, South Philadelphia, West Philadelphia, North Philadelphia, Bridesburg/Kensington/Richmond, East Mt. Airy and East Germantown, as well as parts of Northeast Philadelphia. Combined Sewer Programs One challenge associated with combined sewer systems is the issue of combined sewer overflows, described in further detail below. PWD has current and future planned programs in the combined sewer areas to control overflows. Combined Sewer Overflows During dry weather, the combined sewer system and wastewater treatment plants have the capacity to transport and treat all the sanitary sewage entering the system. However, when flow in the sewer increases as a result of rainfall or snowmelt, the sewer pipes or treatment plants may reach their capacity. When this happens, the EPA permits Philadelphia, as it does other cities with combined sewer systems, to discharge excess wastewater into May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 4 4

5 nearby waterbodies to prevent health and human safety issues that may result from localized flooding in neighborhoods and in treatment plants. There are 164 combined sewer outfalls (CSOs) along the Delaware and Schuylkill rivers and the Cobbs, Tookany/Tacony Frankford, and lower Pennypack creeks. Figure 7 shows the difference between the combined sewer and separate sewers during wet weather. The unfortunate side effect of preventing flooding by allowing CSOs to discharge water is the contamination and erosion of our waterways. As stormwater travels over impervious surfaces, it picks up pollutants, and this polluted water mixes with raw sewage in the combined sewer. When there are overflows, these contaminants end up in our rivers and creeks, causing the waterbodies to be unsafe for recreational use for about 24 hours. The large rush of excess wastewater also scours river and creek beds. The pollution and scouring make it difficult for native plant and animal species to survive, giving way to invasive species and a degraded landscape. Reducing the amount of stormwater that ends up in the combined sewer system can reduce the number of overflows, allowing our waterways to become healthier and more sustainable. Causes of Combined Sewer Overflows Combined sewer overflows may occur for three reasons. Depending on where the rain falls within the City, either treatment plant capacity, interceptor capacity, or the CSO regulating structure could be the limiting factor. If Philadelphia receives evenly spread, low intensity rainfall, the treatment plants may be reach capacity without any interceptors reaching capacity. However, if an inch of rain falls mostly within several sewersheds, the interceptor may reach capacity while the treatment plant does not. Additionally, most regulating structures are designed with a static dam, meaning if the water level rises above the dam height, it overflows. Although the dam is designed to overflow only when the interceptor has reached its capacity, you could theoretically overflow before that time. In addition to these static dams, Philadelphia has several more advanced regulators with computer controlled gates that can better regulate the contribution each sewershed makes to its respective interceptor. For regulators that are tidally influenced, there can be no overflow even when the treatment plant, the interceptor, and the regulator are at capacity if the tide is holding the tide gate shut. This situation could result in street flooding. Why do Combined Sewer Overflows (CSOs) exist? Historically, the combined sewer systems were designed and sized to carry both wastewater and stormwater flow in the same pipe to the treatment plant. As the amount of impervious cover in Philadelphia increased, the amount of stormwater being captured by the collection system also increased. Due to the increase in stormwater runoff from development and poor land use management, combined with population (sanitary) increases, the capacity to carry all the flow in the existing sewer system can be exceeded. To avoid basement flooding, house fixture back ups, and street flooding, the sewer system was designed to provide for overflow points that will send any flow in excess of treatment or carrying capacity to a nearby waterbody. Annual Frequency of CSOs Based on analysis of historical rainfall records from 1902 to 2005, Philadelphia experiences an average of 65 rainfall events per year. Combined sewer overflow frequency depends on numerous conditions, including the size of the sewer and drainage area, precipitation, land use, antecedent moisture conditions, etc. Therefore, some CSOs may discharge every storm, while some discharge only several times a year. As for CSO outfall size, these may range anywhere from 2 ft. in diameter to 21 ft. x 24 ft. rectangular. The quantity, frequency, and impact are unique at each CSO, making it difficult to generalize. The Office of Watersheds hydraulic and hydrologic models estimate annual CSO discharge at about 16 billion gallons from our 164 CSO point sources. Figure 8 shows combined sewer outfalls with annual quantities of overflows. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 5 5

6 Seasonal Variations in CSOs In analyzing historical rainfall records, precipitation is found to be most frequent between April and September. In the summer, all precipitation is rainfall. In the winter, we can expect a mix of rain and snow. In some instances, a rain event occurs when there is snow pack present from previous snowstorms. When this occurs, the sewer system can simultaneously experience runoff from both the precipitation and from snowmelt. In addition, warm days when snow melts actually generate enough runoff to trigger an overflow event. Extent of CSO Problems It is difficult to quantify the extent of the local CSO problem and its relationship to degradation on the ecosystem. CSOs are permitted sites that are necessary for preventing health and human safety issues that may result from localized flooding. PWD is spending tens of millions of dollars per year to mitigate, abate, and/or eliminate CSOs. Water quality issues vary, depending on CSO volume and frequency, land use in the drainage area, existing receiving stream water conditions, the stream s physical dimensions, the season, antecedent weather conditions, future weather conditions, impervious percentage, tide cycles, and other factors. There are also erosion and sedimentation issues within the stream system that may cause habitat problems for fish and macroinvertebrate communities. Aesthetics, odor, and safety issues have also been linked to uncontrolled stormwater runoff. PWD s Approach to CSO Control The Philadelphia Water Department's approach to long term management and control of combined sewer overflows has been integrated with a comprehensive watershed management program. Through a watershedbased planning and management effort, the PWD has developed a control program with three broad goals: LAND Managing wet weather flows at the source through improved land management practices WATER Direct restoration of the aquatic habitat to support living resources INFRASTRUCTURE The upgrade and expansion of infrastructure to further reduce CSO frequency and volume These programs are integrated to provide multiple ecological, aesthetic, and social benefits. Investigation and Mitigation of Flooding Several areas of the City (South Philadelphia, Northern Liberties and Washington Square West) have experienced significant basement flooding during intense rain events. The frequency and intensity of flood producing rain events have increased over the last two years. As a result of these events, the Water Department has initiated an intensive study of the basement flooding situation. The Water Department has begun a hydraulic analysis of the sewer system in the flood prone areas in order to understand the cause of the basement flooding as well as to determine possible solutions. The Water Department has also begun and will continue to schedule flood relief capital projects into its capital program as determined by the hydraulic analysis. Thus far, the Water Department has programmed flood relief projects in Snyder Avenue, in South Philadelphia, and in the Washington Square West area. Due to their complex nature, these projects will take many years to design and construct. In order to provide relief for properties as quickly as possible while the capital solutions are identified, designed, and constructed, the Water Department has budgeted $1.1 million in each of Fiscal Year 2010 and Fiscal Year 2011 for a Backwater Valve installation program. This Backwater Valve installation program will consist of the Water Department hiring private plumbers to evaluate flood prone properties to determine if they would benefit from the installation of a backwater valve or valves. If the determination is positive, then a backwater valve configuration will be engineered for that particular property and installed by a private plumber at the Water Department s cost. The property owners must agree to accept maintenance responsibility for the backwater valve(s). PWD has also established an assistance program to alleviate flooding conditions in basements due to heavy rainstorms. The following zip codes are eligible: 19107, May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 6 6

7 19123, 19145, 19146, and Seventy two (72) properties were served in Fiscal Year 2009 at a total cost of $220, Separate Sewer System The separate sewer system covers about 40% of the sewer service area in Philadelphia with approximately 455 stormwater outfalls throughout the City. A separate sewer system consists of two different sewer pipes running one on top of the other, or piggyback. In most instances, the sanitary pipe is below the storm pipe. The sanitary sewer pipe transports sanitary sewage collected from the laterals (plumbing connections) of homes, businesses, and industry to treatment plants. The stormwater sewer pipe carries water collected from street inlets, building downspouts, and other storm sewer lines to a nearby receiving stream where it is discharged through a Stormwater Outfall. Stormwater Outfalls Although stormwater outfalls are located in every watershed in Philadelphia, most occur in the larger separate sewer regions of the City, particularly in the Wissahickon, Schuylkill, Pennypack and Poquessing watersheds. Approximately 455 stormwater outfalls exist throughout the City. Separate Storm Sewer System Programs As described above, PWD makes investments to control CSOs within the combined sewered area. Stormwater management within separate sewered areas presents different challenges that are also significant, namely water quality and flooding issues. PWD has several programs in place to meet these challenges. Polluted Runoff Although the separate sewer system does not pose immediately apparent environmental hazards and safety concerns (as in the case of the combined sewer system), there is a potential to discharge polluted waters from runoff of buildings and streets (e.g. metals, debris, animal waste, etc.). This concern arises because the water from the stormwater sewer inlets and pipes is not treated before discharging into waterways. Defective Laterals 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 that 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. Waterways Restoration Program Aquatic Resources Project Registry In response to waterway degradation and loss of aquatic resources, PWD has identified numerous opportunities for restoration and enhancement projects. The Aquatic Resources Project Registry includes stream restoration, wetland creation, fish passage and tidal wetland creation. These projects will also help mitigate damage to the environment caused by infrastructure improvements, create economic benefits, and improve recreational value. In addition, many of these projects are located in areas with low income and minority neighborhoods that would be enhanced by the proposed upgrades. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 7 7

8 Stream Restoration/Wetland Creation Projects The Office of Watersheds (OOW), partnering with PWD s Design Group and the Fairmount Park Commission, has hired consultants to develop restoration, stabilization, and wetland creation designs for tributaries and main stem streams throughout Philadelphia County. The OOW oversees the design and construction phases of these projects to ensure that project goals will be met and all applicable permits are being obtained. In order to assess whether or not these built out efforts have been successful, the OOW also conducts pre and post construction monitoring. Fluvial Geomorphology Reports The purpose of the Fluvial Geomorphology (FGM) Stream Assessment Reports is to provide the PWD, local watershed partnership groups, and other stakeholder parties with an analysis and summary of the Philadelphia watersheds existing physical conditions, inclusive of both stream networks and riparian corridors. Specifically, the goals of these assessments are to provide: characterization and documentation of existing conditions a reference point for evaluating changes over time a tool for prioritizing stream and habitat restoration sites insight into appropriate restoration strategies a land use planning and redevelopment tool an aid in determining the effects of urbanization The ultimate goals of these restoration efforts will include: improving water quality, managing or replanting riparian vegetation, enhancing in stream habitat, providing increased fish passage and finally, facilitating stream bank stabilization. Wissahickon Sediment Total Maximum Daily Load (TMDL) Monitoring Program The PWD has developed and implemented this program designed to achieve the first goal of the Wissahickon TMDL for siltation, which requires PWD to establish baseline data on Philadelphia s contribution of sediment loading and flow variations. PWD conducted a study to identify tributaries to the Wissahickon Creek within Philadelphia that cause an adverse impact to in stream habitats as a result of the transport of sediment or stream bank erosion. The study, initiated in October 2005, includes an evaluation of the tributaries that have the greatest potential for improvement through implementation of BMPs or other methods. Riparian Buffer Nursery Through a partnership with the Fairmount Park Commission, we are transforming an urban site within Philadelphia equivalent to 11 typical residential lots into a tree nursery that will use innovative stormwater management techniques to create an aesthetic and environmentally sound model for long term care and maintenance. Once established, our vision for the nursery is that matured trees will be sold and planted throughout the community and adjacent neighborhoods. The trees can also be sold to City agencies and nonprofits for the purposes of tree restoration in City parks. Philadelphia wide Programs Stormwater runoff from almost all the developed areas of the City, whether served by separate stormwater sewers or combined sewers, are causing impairment to the aquatic and riparian habitats of streams and rivers in Philadelphia. These water bodies are suffering from streambank and channel erosion resulting in the exposure of sewer infrastructure, and decreased stream baseflow due to reduced groundwater recharge. The streams do not support healthy aquatic communities, do not meet uses designated by the State, do not serve as amenities to the community, and occasionally cause property damage due to flooding. In addition, stormwater is an important May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 8 8

9 source of pollution to the drinking water intakes on the Schuylkill and Delaware Rivers. Philadelphia s 2006 development regulations require that water quality, channel protection, and flood protection measures be implemented for new and redevelopment. May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 9 9

10 Figure 1 Locations of Water Treatment Plants Figure 2 Locations of Water Pumping Stations May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 10 10

11 Figure 3 Locations of Wastewater Treatment Plants Figure 4 Locations of Wastewater Pumping Stations May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 11 11

12 Figure 5 Historic and Current Waterways Figure 6 Two Types of Sewer Systems (Dry Weather) May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 12 12

13 Figure 7 Two Types of Sewer Systems (Wet Weather) May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 13 13

14 Figure 8 Combined Sewered Areas Showing Locations of CSOs by Volume May 19, 2011 PWD CAC System Handout 17MAY11 V2.docx 14 14