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Subject
Briefing on the City of Rockville Water System.
Recommendation
Staff recommends the Mayor and Council receive staff briefing on a program of proposed water treatment plant upgrades and the 15-year infrastructure renewal of the water distribution system.
Change in Law or Policy
Staff will return on a future agenda with rate schedules needed to accomplish this program. Changes to the water and sewer rate schedule will require amending the City Code, Chapter 24, "Water, Sewers and Sewage Disposal." Chapter 24 also provides for certain fees to be established by resolution. Any changes to those fees established by resolution will require the adoption of new resolutions.
Discussion
The primary purpose for public water systems is to deliver clean and safe water for human consumption, fire suppression, industrial processes and agriculture. Rockville's system primarily serves human consumption (drinking, washing, laundering, watering lawns, washing cars, heating and air conditioning), fire suppression, and limited industrial and agricultural purposes. Rockville's water system consists of a Water Treatment Plant (WTP) and Water Distribution System.
The purpose of this agenda item is to highlight several issues impacting the City's water system and infrastructure. Systems across the region and the nation are facing similar issues regarding significant upgrades to their water treatment plants and water distribution systems which are being driven by increasingly stringent federal water requirements, aging infrastructure, and pipe conditions that impact fireflow and water quality. This worksession provides an overview of the complex issues affecting the City's water treatment plant and distribution system, upgrades needed at the water plant, and a plan to replace a large portion of our water lines over the next 15 years. The financial implications will be discussed at a future Mayor and Council worksession with rates and options to pay for these essential infrastructure upgrades.
Water Treatment Plant
Initially, Rockville received water from a number of wells spread throughout the city. In the mid-1950s these wells were no longer able to keep up with the increased demand created by the booming post World War II economy and the associated development. From 1950 to 1960 Rockville's population increased by 276 percent. This surge in population and associated development overtaxed both the water and sewer systems to the point of crisis in 1953, which contributed to the formation of the Citizens for Good Government (CCG) and the election of an entirely new Mayor and Council in 1954.
In the mid-1950s, the City focused its attention on building a state-of-the-art water plant to provide a reliable water source that would withdraw "raw" water from the Potomac River, process and treat it, and then deliver "finished" water to Rockville residents. Rockville hired Gilbert Associates to design the water intake structure and high-rate, dual-media filter purification water plant with chlorine disinfection. Public Works began operating the Water Treatment Plant (WTP) in 1958; with an initial plant capacity of 4 million gallons per day (mgd). In 1969 a plant expansion was completed bringing the WTP capacity from 4 mgd to 8 mgd.
Over the years there have been process improvements to yield cleaner water to meet more stringent requirements mandated by Congress, with rules and regulations set by the Environmental Protection Agency (EPA) and Maryland Department of the Environment (MDE). Rockville initiated a Water Plant Rehabilitation Program in the mid 1990's to address EPA standards for the 1986 Safe Drinking Water Act (SDWA) Amendment.
Rockville's Water Plant Rehabilitation Program, which began with the Solids Removal project and also included Intake Upgrade, Clarifier Upgrade, Sandy Landing Road Improvements, Filter Rehabilitation, Filter Cover, and WTP Pump Upgrades, was implemented over an eleven-year period beginning in 1993. Before 1996, the silt removed from the raw water was discharged back to the Potomac River. In 1992 the MDE issued a Consent Decree ordering Rockville to stop discharging silt to the Potomac River. Accordingly, a solids handling system was implemented in 1996 to comply with the Consent Decree. Rockville invested $10 million on this Program between 1993 and 2004 to improve the water plant and intake to comply with EPA and MDE regulations.
EPA promulgated two new regulations in 2006: The Long Term 2 Enhanced Surface Water Treatment Rule (LT2 Rule) and the Stage 2 Disinfectants/Disinfection By-Products Rule (Stage 2 DBPR). Water Systems must comply with these regulations by 2013. A brief description of each follows:
- The LT2 Rule requires process improvements to reduce disease incidence associated with the presence of Cryptosporidium and other pathogenic microorganisms in drinking water. Cryptosporidium is a significant concern because it contaminates surface waters used as drinking water sources and is resistant to chlorine and other disinfectants. In addition, it has caused waterborne disease outbreaks, such as gastrointestinal illness, which may be severe in people with weakened immune systems (e.g., infants and the elderly) and sometimes fatal in people with severely compromised immune systems (e.g., cancer and AIDS patients).
- The Stage 2 DBPR requires process improvements to protect public health by limiting exposure to "disinfection by-products." Disinfection is an essential element of drinking water treatment because of the barrier it provides against waterborne disease-causing microorganisms. However, disinfection by-products (DBPs) form when disinfectants used to treat drinking water react with naturally occurring materials in the water (e.g., decomposing plant material). These by-products (Trihalomethanes (THM), Haloacetic acids (HAA), Chlorite, and Bromate), if consumed in excess of EPA's standard over many years, may lead to increased health risks for cancer, as well as possible cause of reproductive and developmental issues.
In 2006, Rockville hired a consulting firm, Hazen and Sawyer (H&S), to evaluate the WTP and its supporting facilities and prepare a comprehensive Water Treatment Plant Facility Plan to:
- Identify required process improvements that meet or exceed the SDWA amendments for LT2 and Stage 2 DBPR;
- Evaluate the plant's residuals handling process to identify ways to improve performance and reliability;
- Evaluate the plant hydraulics to meet 14 mgd; and
- Evaluate capacity of the electrical components to support recommended process changes to the plant.
Previous studies indicated that 14 mgd plant production capacity was needed to meet future demand; however, recent projections performed by H&S as part of the 2008 Water Distribution Master Plan, indicate the maximum demand will be 11 mgd. As some components have not already been sized to meet the 14 mgd output, an analysis will be done to determine the cost-effectiveness of upgrading those remaining components to 11 mgd rather than the original 14 mgd.
The WTP Facility Plan was split into two phases: Phase A and Phase B. The Phase A Study, completed in June 2007, assessed the ability of the existing plant to comply with current and projected drinking water regulations; identified unit processes that need to be upgraded to achieve the increased plant capacity; and evaluated the existing residuals handling processes to improve performance and reliability. Further, Phase A recommends performance testing of the clarification process (Clarifiers) to be accomplished during Phase B because this unit process is nearing maximum production and therefore could limit the overall WTP production capacity. Phase A of the Water Treatment Plant Systems Analysis projected a $14.6 million improvement plan, which includes:
- Solids Handling Improvements;
- Filter Improvements; and
- Chemical Feed Upgrades.
The solids handling improvements are needed to prevent the existing treatment process from being compromised during storm events on the Potomac River and to allow the plant to increase production to meet increasing demand for finished drinking water. The filter improvements and chemical feed upgrades are needed to improve plant performance relative to finished water quality goals at higher plant flow rates and bring the existing units into compliance for plant design criteria (MDE Regulations, the Ten States Standards, etc.).
What is not included in the above cost is the cost of electrical improvements, hydraulic improvements, or the cost of advanced treatment processes to achieve compliance with the Long Term 2 or Stage 2 DBP Rules. The latter could not be quantified during Phase A because:
- The 24-months of raw water Cryptosporidium sampling had not been initiated at the time the report was completed; therefore, a classification of where the Rockville WTP stood relative to the additional treatment requirements of the LT2 Regulation could not be ascertained. The Phase A report recommended that the City begin considering its options for complying with the worst case classification scenario under this regulation. This analysis was to occur in Phase B.
- Insufficient data was available to ascertain if the City would meet the regulatory criteria or not.
The $14.6 million cost also did not include the cost of additional filtration or clarification because the full-scale performance testing had not been performed. The full-scale testing program should cover multiple seasons (cold and warm water conditions, which can affect treatment), and should be coordinated with the Maryland Department of the Environment so that State buy-in to the testing program can be obtained.
Because of the high cost of these improvements, and because of the unknown nature of the LT2 and Stage 2 DBP Rules, H&S recommended a cost-benefit analysis be included in Phase B to include other advanced process alternatives to lay out a long-term capital improvements program for the City of Rockville WTP. Additionally, data from the component performance testing will be used to evaluate cost-effectiveness of specific process component upgrades. Phase B of the Water Plant Study and Facility Plan, which was initiated in fall 2007 and will be completed in fall 2008, will evaluate the hydraulic capacity, electrical system capacity, as well as consider additional or alternate process changes (to those presented in the Phase A report) to meet regulatory compliance assuming a worst-case result to the additional analysis for LT2 and Stage 2 DBP Rule compliance.
When taken together, the Phase A and Phase B analyses will constitute an overall Facility Plan for the Rockville WTP. The final Facility Plan will recommend a long-term upgrade program to achieve cost-effective solutions for:
- Regulatory compliance for LT2 and DBPR;
- Hydraulic constraints;
- Hydraulic surges associated with power outages; and
- Improve the electrical components to support future plant process demands.
Water Distribution System
The water distribution system, a network of water meters, storage tanks, pumps, pipes, fire hydrants, and valves, transports the finished water from the WTP to Rockville's customers. Rockville is among many communities nationwide that are facing four issues inherent to its aging distribution system: decreased revenue caused by aging water meters; increased water main breaks; decreased water quality within the distribution system; and decreased flow rates for fire suppression.
Water Meter Replacement
Aging water meters tend to "slow down" and under-register the amount of water consumed. The Meter Replacement Program, projected to cost $5 million, began in 2006 with the commercial meters. The residential meter replacement program will begin in spring 2008. All water meters will be replaced by fall 2009. Revenues are expected to increase because water usage will be more accurately measured and billed.
Water Tank Rehabilitation
Rockville's development in the 1950s and 1960s added five water storage tanks and 93 miles of water pipe; more than quadrupling the size of the water system. The 1994 Water Distribution Study analyzed the overall system and determined two tanks (Grandin Ave and Horners Lane) were no longer needed. Accordingly, they were removed in 1998 and 2000. The remaining three water tanks (Talbott Ave, Carr Ave, and Hunting Hill) were rehabilitated between 1996 and 2000. The tanks were repaired and painted with a sealant on the interior and exterior to protect against corrosion. Additionally, cathodic protection systems were installed. Cathodic protection controls the corrosion of a metal surface by making that surface less prone to corrosion by introducing a sacrificial element (anode) that corrodes instead of the metal surface (the water tank). Rockville invested $3.5 million to remove the two tanks and rehabilitate the three other tanks.
Glen Mill Pump Station
Rockville constructed the Glen Mill Pump Station (GMPS) to allow increased water production over 8 mgd based on a recommendation from the 1992 Water System Study. GMPS is located within Montgomery County approximately halfway between the WTP and the Hunting Hill Water Tank. Construction on the station was completed and field-tested in fall, 2006; however it has not been put into routine operation because there have been problems identified by staff related to surges, valves, pumps, and air release valves. Staff received a study conducted by H&S to review these problems and they have recommended solutions that have resulted in two new CIP projects to implement these improvements: Hydraulic Surge Suppression and Air Release Valves.
Water Pipes and Breaks
The water pipes installed during this post World War II boom (1950s and 60s) represents 51% percent of our total water distribution system today (see Attachment 1 - Water System Pipes & Customers, City of Rockville). The industry standard pipe for water distribution systems at that time was cast iron pipe without interior lining and without exterior protection. There are three primary measures for determining the need to replace/rehabilitate pipes: structural condition (leading to leaks and breaks), water quality, and water flow (tuberculation). While the age of a pipe is an indicator of its condition, the actual service life of a particular segment of cast iron pipe may vary considerably depending on the above factors. Pipe installed today (ductile iron pipe with an interior cement lining and with exterior polywrap) has a life expectancy of 100 years or more. Unlined cast iron pipe can have a life expectancy which is considerably less.
Failures in aging water mains are a problem for Rockville and many other water utilities. Water main breaks cause property damage, revenue loss, environmental damage, interruption of service, and costly repairs for water customers. Two recent water main breaks on Rockville Pike resulted in major service disruptions, took crews 29 hours to repair, interrupted traffic through several rush hours, and resulted in an estimated 1.4 million gallons of lost water ($3,750 loss of revenue). In 2007, Rockville experienced a record 65 water main breaks, costing approximately $250,000 for repairs, and much water loss.
Rockville's aging water pipes will continue to experience increased breaks unless a pro-active and systematic replacement program is initiated. Of the system's 180 miles of pipe in the distribution system, approximately 90 miles is cast iron pipe installed before the mid 1970s. Increased water main breaks in the cast iron water pipes are anticipated as the pipes age.
Water Quality
Water main breaks are not the only problem with an aging water system. Unlined cast iron pipes are subject to internal corrosion, known as "tuberculation," which degrades the quality of the water and causes flow restrictions. Water quality issues are two-fold: discoloration of the water, and decreased availability of chlorine residuals for disinfection.
Tuberculated pipes can cause water to turn a rusty brown color. A slight increase in water velocity, as may be experienced during opening of a hydrant or during a main break, can cause the rust to break loose from the interior pipe wall, resulting in discolored tap water. High water demands throughout the distribution system also increase the velocity of the water to a rate of flow which causes water discoloration.
As part of Rockville's regular maintenance program, all of the water mains in the distribution system are flushed every other year. This flushing helps to remove the internal build-up of material before it reaches homes and reduces incidents of water discoloration.
Tuberculated pipes also affect the quality of drinking water by reducing the amount of available chlorine for disinfection purposes. Utility companies throughout the nation commonly use two procedures to maintain adequate chlorine in the distribution system. The first is to add extra chlorine at the treatment plant to ensure that sufficient residual chlorine is available at the most distant point in the distribution system. However, simply adding more chlorine introduces the risk of forming additional disinfection by-products (DBPRs). As mentioned earlier in the WTP section, DBPR levels are also regulated. The second procedure to maintain chlorine levels is to flush water mains, as discussed for controlling incidents of water discoloration. Currently reduced chlorine availability occurs infrequently in Rockville's severely tuberculated pipes. Rockville takes monthly samples at 25 locations throughout the water distribution system to test for various components, including chlorine residuals. These samples consistently meet or exceed current regulatory requirements. However, continued tuberculation growth could lead to increased incidences of low chlorine residuals.
Flushing water mains is a standard industry preventive maintenance procedure to improve water quality, as well as to test the system’s fire hydrants to ensure they are in good working condition. However, flushing water mains is not enough to address discoloration and low chlorine residuals when the pipes have extensive tuberculation.
Restricted Flow
Another significant impact of tuberculation is reduced water flow. Tuberculation reduces the internal pipe diameter and causes the internal pipe surface to become rough. Both of these conditions decrease flow and pressure in the pipe. Typically, the tuberculation build-up progresses over time, steadily lowering the water flow rate. After many years of build-up, tuberculation lowers the flow to a point where it impacts the ability to meet fire flow demands.
Rockville hired H&S in 2006 to prepare Rockville's Water Distribution System Master Plan (see Attachment 2). This is the fourth Water Distribution System Study of Rockville's system during the past 40 years, but the first to use a sophisticated all-pipe computer modeling program to evaluate the entire water distribution system and develop a comprehensive improvement program to correct deficiencies. The study included field testing as well as the creation of a GIS compatible, all-pipe network computer model. A GIS compatible model will allow Rockville to integrate computer modeling with the physical data of the pipe network. Field-testing was used to calibrate the computer model and determine the flow capability of water mains. The calibrated model, along with field-testing results, revealed flow deficiencies primarily in the older sections of town with the unlined cast iron pipe within the neighborhood streets.
Because tuberculation cannot be measured directly, computer modeling is used to predict the amount of available flow at various points in the system and determine the system’s ability to meet fire flow demand. Guidelines for fire flow for varying development densities are published by ISO (Insurance Service Office). Rockville has historically followed the fire flow guidelines established by ISO. For most water systems, the recommendations vary from 1,000 gpm (gallons per minute) in residential areas to 3,500 gpm for major commercial or industrial development. The study found 257 out of Rockville's 1369 fire hydrants are delivering fire flows less than 1,000 gpm. Forty-one of the 257 fire hydrants deliver fire flow less than 500 gpm.
Staff met with the Montgomery County Fire and Rescue Service (MCFRS) to review Rockville's system ability to deliver sufficient fire flow. MCFRS indicates that fire hydrants that deliver 500 gpm, though not ideal, can be used to put out a residential fire. Fire hydrants that deliver less than 500 gpm are generally considered insufficient. Rockville intends to manage these deficiencies through continued coordination with the MCFRS while the water line renewal program is implemented. For example, a fire hydrant marking program is being developed in conjunction with the MCFRS to field-identify hydrants that deliver less than 500 gpm and hydrants that deliver over 500, but less than 1,000 gpm. In the event of a fire this will allow firefighters to quickly determine which hydrant to draw water. The fire hydrant marking program is a tool to bridge the system from partial fire flow inadequacies to a system that provides adequate fire flows. Staff also plans to share GIS mapping layers of the water distribution system with MCFRS which can be used as needed. A program must be initiated to replace these deficient lines so that fire flow in these areas can be restored to an acceptable level and it must be done in a time frame that prevents this from reaching a crisis stage.
Water Line Replacement Program
To address the fire suppression and other deficiencies H&S Water Distribution Master Plan recommends replacing 32.9 miles of water pipe at a cost of $67 million over the next 15-years. The water line replacement has been prioritized into four groups. The groupings were developed to provide fire flow improvements expeditiously, minimize water service interruptions due to breaks and resulting inconvenience to Rockville residents, improve water quality to an interconnected system of pipe within each different area of Rockville, and group together projects that must be completed together in order to achieve the goals and benefits of the program. The 15-year pipe replacement program is shown in the Executive Summary (see Attachments 2 and 3 - Executive Summary and Figure ES-1, Recommended Improvements). Beyond the first two years, projects may vary according to maintenance needs, such as frequency and magnitude of breaks.
Rockville must begin implementation of a planned water line replacement program to ensure a sustainable water distribution system that will provide sufficient water flow for fire suppression and water quality that meets or exceeds EPA and MDE regulations, while minimizing future operation and maintenance costs and service interruptions.
Staffing for the New Program
Taking together the $67 million water replacement program and the $14.6 million WTP Upgrade Program represents approximately $82 million in capital expenditures over 15 years. While most of the actual work will be accomplished through contractors, Rockville does not have sufficient resources to manage this at current staffing levels. To meet this demand staff will require approximately 4.5 additional staff positions (regular and temporary positions) in the Water Fund to manage, engineer, and execute the program.
Mayor and Council History
This is the first time this item has been brought before the Mayor and Council.
Options Considered
Water Treatment Plant
Specific options are being considered as part of the Phase B Study analysis. The plant upgrades needed for regulatory compliance must be completed by 2013. The "no-build" option is not considered, because these projects are mandated by federal and state regulations.
Water Distribution System
Staff considered two options to address concerns due to the aging water distribution system: "Clean and Line," or "Dig and Replace." Cleaning and lining water lines can be an effective means to remove tuberculation and restore the internal surface of the pipe thereby improving flow and water quality. This process uses a machine that is drawn though the pipe to scrape the tuberculated materials from the surface and then spray a cement lining onto the pipe's interior. The City has previously performed cleaning and lining on several transmission mains, based on prior recommendations to address similar issues. However, cleaning and lining does not improve the pipe's structural integrity and water main breaks will continue to occur.
A dig and replace program removes the old pipe and replaces it with new pipe that meets today's standards of lined and wrapped ductile iron pipe. Replacement also offers an opportunity to replace deteriorated valves, hydrants, service connections to the meters at the customer's property line, and upsize mains, thereby, providing a more complete renewal of the system and attaining maximum benefit for the cost of the renewal program. While initially more expensive than cleaning and lining, the life-cycle cost is lower because the pipe's service life has been dramatically increased. In addition, future water main breaks will be minimized. For these reasons staff recommended the dig and replace program.
The "no-build" option is not considered because there will be serious consequences to Rockville's distribution system if the infrastructure is not improved. Specific examples include increased fire protection problems, water quality degradation; and increasing frequency of water main breaks.
Public Notification and Engagement
Staff is planning an aggressive campaign to educate Rockville residents about the aging water system and the need to rehabilitate the various components. Staff plans to publish a two-part series in Rockville Reports in the March and April issues; broadcast a Cityline interview on TRC 11; and include a short news story in the city hall report on TRC 11 to be aired during the week of February 11. Additionally, staff will prepare a FAQ to be posted on the City Web site; place press releases on the front page of Rockville's Web site; and provide links to Mayor and Council power point presentations, staff reports from Mayor and Council meetings, and Rockville Reports articles.
Fiscal Impact
Many other utilities in this region and nationwide are faced with the need to invest in their water systems. In 2002, EPA published The Clean Water and Drinking Water Infrastructure Gap Analysis which included a funding analysis. EPA's cost projections, including financing, ranged from $178 billion to $475 billion needed nationwide to address aging infrastructure renewal as well as regulatory compliance with tougher environmental standards. EPA's analysis suggests that a large gap will result if the challenge posed by an aging infrastructure network—a significant portion of which is beginning to reach the end of its useful life—is ignored.
The FY 2009 CIP will propose a $14.6 million WTP Upgrade Program, which appeared in the FY 2008 CIP, and a $67 million 15-year water distribution system infrastructure renewal program.
The infrastructure renewal will be an on-going program, similar to the Asphalt Pavement Maintenance and Concrete Repair programs. Both of these existing infrastructure renewal programs cycle rehabilitation work through the City on a regular schedule based on the life cycle of asphalt roadways and concrete curbs, gutters, sidewalks, and driveway aprons. Funding options will be developed to ensure the cost is equitably shared amongst the users of the entire water system.
Initially, the 15-year water infrastructure program recommended by H&S addresses the most critical and older sections of Rockville with water pipes nearing the end of their life-cycle. As future Water Distribution Master Plan Studies are conducted, and water main break information as well as water quality information are compiled, additional water pipes will be replaced. The newly installed water mains will have an anticipated life cycle of 100 years. Therefore, on average approximately 1.8 miles of water main will need to be replaced annually once the initial program addresses the critical mass of water mains installed in the 1950s and 1960s.
Staff is currently looking at different approaches for financing such significant operating and capital improvement expenses, including an approach proposed by WSSC to address similar problems. For FY 2009, WSSC is proposing an aggressive pipe replacement program and is recommending an Infrastructure Renewal Fee (ready-to-serve charge) for all customers, based on meter size, as a flat monthly fee for the next ten years. For small meters, size 5/8" to 1-1/2," the monthly fee will be $20. Staff is in the process of running different iterations of usage rates and ready-to-serve charges and will make recommendations with the principle of having the lowest rates over time for Rockville residents, while ensuring that costs are equitably distributed to all system users.
Next Steps
Staff will present funding and rate recommendations at an upcoming Mayor and Council Session and initiate public education.
Attachments
  
Attachment 1: Water System Pipes and Residential Population Served
Attachment 2: Executive Summary
Attachment 3: Figure ES-1, Recommended Improvements
Attachment 4 Water Briefing Powerpoint
Department Head:
Craig Simoneau, P.E.; , Director of Public Works
Approved on: 02/07/2008
City Manager:
Scott Ullery, City Manager
Approved on: 02/07/2008
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