Fairfax County, Collecting Real Data to Model the Watershed

Potomac Watershed Round Table met on Friday, April 4th in the Fairfax County Herrity Building. The meetings are open so you are welcome to attend. As usual there were several stimulating presentations about programs operating in the Potomac Watershed and threats to our watershed. Shannon Curtis an Ecologist with the Fairfax Count Stormwater Planning Division spoke to the group about the evolution of the water monitoring program in Fairfax County Virginia and the long-term monitoring partnership between Fairfax County and the United States Geological Survey (USGS) that began in 2007.

Back in the 1980’s ecosystem monitoring by Fairfax County and others discovered that there is an ecosystem response time lag of 10-15 years (either positive of negative) to changes in the landscape. Traditional development practices cover large areas of the ground with impervious surfaces such as roads, driveways, sidewalks and buildings. Slowly, but surely this changes the ecosystem. The paved and impervious surfaces prevent rainwater from infiltrating into the ground, causing it to runoff site at velocities and volumes that are much higher than would naturally occur, carrying with it pollutants, oil and grease, and litter.

The collective force of high velocity rainwater scours streams and over time erodes stream banks carrying sediment and other pollutants into the streams, rivers, estuaries and bays. The US EPA believes that sediment and nutrient pollutions contained in runoff from urban areas is the largest source of water quality impairments to estuaries (areas near the coast where seawater mixes with freshwater) in the United States and has turned its water quality focus on these areas starting with the Chesapeake Bay Watershed and moving forward with the Gulf Coast estuaries.

Nationally, billions of dollars are being spent to implement stormwater best management practices and low impact development strategies based on computer simulations and models. In Virginia alone millions upon millions of dollars are expect to be spent on stormwater best management practices in the next 10 years. Fairfax county programs are helping to understand how well these programs work. The Fairfax County Stormwater Planning Division performed a baseline study of the condition of all the streams in Fairfax County in the late 1990;s and found at the time that three quarters of the streams were in fair, poor or very poor condition. The deterioration of the streams had resulted from the development of the county over the previous 40 years.

This finding was used to develop the stream protection and management plan. Then in 2007 Fairfax County Stormwater Planning Division and the USGS began a long-term monitoring effort to identify countywide conditions and trends in stream water quality and quantity. The first five years of data has been accumulated by the program. The information collected will be used to evaluate the benefits of past and future watershed improvement projects. There are currently twenty monitoring stations (recently expanded from 14) in the county collecting data. Fifteen of these sites are monitored manually on a monthly basis; the remaining five sites are equipped with automated stream gages which are monitored continuously.

Stream gage in Fairfax from USGS

Instruments at the five automated gages measure six indicators every 15 minutes and during storm events: water temperature, dissolved oxygen, pH, specific conductance (a measurement of the dissolved solids in the water), turbidity, and during the storm events sediment and nutrient (nitrogen and phosphorus) concentrations. The manual stations are sampled monthly. These gages cover and area of less than six square miles. It is hoped that this data will allow the USGS and Fairfax County to observe small and subtle changes over time.

The first five years of data (when there were only 14 gages in operation) has recently been accumulated and analyzed by the USGS and provides a baseline of the condition of the watershed based on real data and not US EPA’s Chesapeake Bay Model. The Urban loading modules of the Chesapeake Bay Model are believed to have the greatest uncertainties and this is a great opportunity to perform a “reality check” on the EPA’s oversight of the water quality in the Chesapeake Bay. EPA is using the Total Maximum Daily Load (TMDL) for nitrogen, phosphorus and sediment mandated to the six Chesapeake Bay Watershed states (Virginia, Maryland, Delaware, New York, Pennsylvania and West Virginia) and the District of the Columbia to manage contamination in the Chesapeake Bay Watershed.

The TMDL sets a total Chesapeake Bay watershed limit for the entire region of 185.9 million pounds of nitrogen, 12.5 million pounds of phosphorus and 6.45 billion pounds of sediment per year which is a 25% reduction in nitrogen, 24% reduction in phosphorus and 20 %t reduction in sediment from the current levels. The pollution limits are then partitioned to the various jurisdictions and river basins based on the Chesapeake Bay modeling tools. Now, the data that the USGS Gages Partnership with Fairfax County can provide a baseline of the condition of the watershed based on data not modeling by the EPA. So far they have discovered that high phosphorus in the western portion of the county is a naturally occurring deposit that was formed about 200-250 million years ago during the Triassic period and unlikely to be remediated by any stormwater or agricultural best management practices.

In addition, the monitoring has shown that stream conditions within the county have not changed much since 1998 when the Stream Protection Strategy base study was performed, though Mr. Curtis pointed out that there might be a subtle improvement in the data, but it could be a function of weather conditions, time will tell. However, during the past 15 years the county has grown in population and development increasing the pressure on the streams, so a steady stream condition might be a small victory.

Cleaning stormwater runoff is very expensive. Preventing stormwater runoff using green infrastructure and low impact development strategies appears to be effective, but is difficult to implement and maintain. Low Impact Development and green infrastructure are a series strategies for stormwater management emphasizing water capture and conservation using natural features to mimic as closely as possible natural hydraulic properties of a site. The idea is to reduce runoff with strategies like green roofs and rain gardens and move water slowly through open unpaved areas to allow infiltration of rain water into the earth. This reduces the quantity and velocity of stormwater as it leaves a site reducing the damage that uncontrolled stormwater runoff created by building roads, sidewalks, playgrounds, and structures and compacting soil can cause.

Nonetheless, the data gathering and work performed in Fairfax raises the question of whether it is possible for urban streams to ever fully recover. Those cleanup goals may not be realistic or attainable. Fairfax County is looking to discover what is the “best attainable conditions” for its streams. In addressing pollution from runoff each step requires consistent and sustained behavior modification of individual citizens working with government. Human behavior is very slow to change and maintaining stormwater best management practices is something each individual must do for the plan to succeed.

Earth Day is April 22

This coming Monday, April 22 marks the 43^rd Earth Day. The first U.S. celebration of Earth Day was held on April 22, 1970. Back in the 1970's early Earth Days celebrated at Waterside Mall (the old home of the U.S. Environmental Protection Agency) were more like solar festivals- one year we built a solar oven, but it ended up taking hours to cook lunch! Things change.

 

The 2012 River cleanup. Image from PWSWCD

Like Arbor Day which is also celebrated at this time of year, Earth Day is a way to remind ourselves that we are citizens of the earth and our address is our watershed. Solar “Happenings” are a thing of the past and today we plan events and engage our children so that we all may step back from our  lives (or handheld devices) and see how our actions and choices can impact our watershed (land and air) and onto to the greater earth beyond.   

Earth Day has evolved into an opportunity to spend a few hours outside with others cleaning up the trash from our water ways and road ways, planting trees and nature walks in our many regional parks to appreciate the trees. The trees act as natural pollution filters. Their canopies, trunks, roots, and associated soil filter polluted sediment from the runoff to our Chesapeake Bay. Trees also use and recycle nitrogen and phosphorus which contribute to the decay of the Chesapeake Bay and its estuary. Cleaning our roadways prevents the trash from being carried along by stormwater and wind into our waterways and parks disrupting the natural water flow and beauty of our natural world.

The Annual Potomac River Watershed Cleanup coordinated by the Alice Ferguson Foundation working with the region’s soil and water conservation districts, community groups, employers, and schools happens this time of year. The Potomac River Watershed Cleanup is the largest regional event of its kind and happens over several weekends so that you or your group can participate. Though the big Occoquan Bay cleanup was last weekend, the Occoquan River and Belmont Bay cleanups are on April 27th 2013.

You can join the Fairfax County Water Authority, the Virginia Department Conservation and Recreation, American Water, Northern Virginia Regional Park Authority and Friends of the Occoquan to plant trees and cleanup the Occoquan River and Belmont Bay. They will be collecting trash along the banks and those volunteers that have boats, kayaks or canoes are encouraged to bring them and remove trash from the water.  (You can sign up and get more information from their web site.) The cleanup begins from five different sites along the Occoquan beginning at 9 am and running to noon.

The five locations are:

• Lake Ridge Marina at 12350 Cotton Mill Drive, Lake Ridge, VA 22192. The coordinator for this location is Renate G. Vanegas Tel. (703) 674-6659.
• Town of Occoquan location is at  314 Mill Street, Occoquan, VA 22125. The coordinator for this location is Claudia A. Cruise Tel. (703) 491-1918, Ext. 11.  
• Occoquan Regional Park at 9751 Ox Road, Lorton, VA 22079. The coordinator for this location is Alex Vanegas Tel. (703) 674-7847.
• Bull Run Marina at 12619 Old Yates Ford Rd., Clifton, VA 20124. The coordinator for this location is John Rothrock Tel. (703) 887-1124.  
• The fifth location is Fountainhead Park at10875 Hampton Rd., Fairfax Station, VA 22039. The coordinator for this location is Sarah Hutton (703) 624-6124.

 Around Prince William County there are a spattering of upcoming activities to celebrate Earth Day. The only event actually on Earth Day seems to be the Kerxton Insurance Agency highway cleanup for their adopted  section of Route 29 (Lee Highway) between Pageland Road and Linden Hall Road in Gainesville, VA. They adopted this section of Lee Highway last winter and is holding  their first cleanup on April 22, 2013 between 2 pm and 4 pm. “Team” Kerxton will be cleaning up their stretch of Lee Highway between Route 66 and Pageland Road (for safety reasons they are avoiding the construction zone between Route 66 and Linden Hall Road.  Kerxton has committed to clean up their stretch of highway four times a year and welcome community help. Contact Tina Stein at (703) 652-6198 or Tstein@kerxton.com The adopt a highway cleanup and the river cleanups are a great way to show our community spirit and help the earth and actually live our values.

In case it’s beautiful out this weekend there are other happenings this week end relating to nature:

On Saturday, April 20^th 2013 the Master Gardeners (trained and certified by the Extension Office) will be having two events:

“Wildflower Walk and Talk,” master gardener Jeannie Couch leads a one-mile walk among native wildflowers. 1pm – 3 pm, at the Brentsville Courthouse Historic Centre, 12229 Bristow Rd., Bristow. The event is free, but  registration  is required. 703-792-7747.

“Saturday in the Garden,” master gardener volunteers discuss growing plants in pots. 9 am.-noon, in the garden at St. Benedict Monastery, 9535 Linton Hall Rd., Bristow. The event is free, but registration required. 703-792-7747.

Can the Grease to Keep Sewers Flowing

Starting this week you might begin to see utility trucks in Fairfax with signs to “Can the Grease” or “Stop the Grease.” Fairfax County Department of Public works is launching a new education and public awareness campaign to get you to stop pouring grease down the drain. When you flush it down the toilet, grind it in the garbage disposal, pour it down the drain in Fairfax county, most likely the wastewater and all that it carries with it travels through the 3,300 miles of sewer pipes within Fairfax county and ends up at one of six regional waste water treatment plants for the county: Noman C. Cole, Upper Occoquan Service Authority, Blue Plains, Alexandria Renew Enterprise, Arlington and Mooney in Prince William.  There are still a few areas in Fairfax that have septic systems covering the rest.

Fats, Oil and Grease, FOG as it is called in the waste industry comes primarily from food such as cooking oil, lard, shortening, meat fats, sauces, gravy, mayonnaise, butter, ice cream and soups. Sinks, dishwashers, cleaning wastewaters and food scraps put down disposals deliver the FOG to the sewer system, it can be liquid or solid when you put it down the drain, but turns viscous or solid as it cools in the miles of underground sewer pipes. As the FOG builds up, it restricts the flow in the pipe and can cause sewage to back up into homes and businesses, or premature failure of the sewer pipes, increased incidence of sinkholes. I was fortunate to be able to speak to Tom Russell, Director, Wastewater Collection Division Fairfax County, VA DPWES who manages the 140 employees and construction programs that keep the sewage flowing in Fairfax and has been with Wastewater Collection 16 years- about half his career as an Engineer and manager with Fairfax. Tom made sewer pipe maintenance sound so interesting that I took way too much of his time during an early morning interview.

FOG only really creates problems for the sewer lines if there is a disruption, like a tree root in a joint, or sag under a highway, a pumping station or something that might give the FOG a chance to catch on the pipe surface and cling to the walls of the sewer system. Since all pipes have some friction points, FOG is always a problem.  The FOG builds up one layer at a time making a smaller, narrower path for the water and waste to travel through, ultimately causing a backup or pipe to burst. Restaurants and fast food places produce much larger volumes of FOG than residences, so in Fairfax there is more aggressive monitoring of sewer pipes and manholes downstream of the malls and shopping centers. Time creates wear and tear on a pipe and without the aggressive maintenance in Fairfax there would be a much larger problem. In addition, restaurants and commercial kitchens are required to have grease traps between the sink and floor drains and the sewer connection and capture and recycle their grease, by having it hauled away. Nonetheless, this past year, there was a massive sewage back up along the side of I-66 across from Fair Oaks Mall. The 18 inch sewer main under I-66 will be replaced at a cost of $1,000,000 and completed in spring 2013, the Wastewater Collection Division has managed to prevent additional backups in the interim by getting the Health Department to address the compliance of the restaurants in the mall with the county regulations for grease and commercial kitchens. Better control of the grease in the mall food court prevented further backups in the damaged section of piping.

Maintaining the sewer pipes, clearing tree roots and keeping grease out of the system can prevent most sewer backups. Every day the Wastewater Collection Division does visual inspections of sewer lines and manholes using portable cameras put down manholes and a special closed circuit TV camera, CCTV, that the crews use. The manhole inspections are generally done in the neighborhoods and the larger sewer mains are checked using CCTV. The CCTV crews use their equipment to view 240 miles of sewer lines each year. Sewer lines range in size from 8-72 inch diameter, and the CCTV is used to monitor deterioration in the lines. There are 88,000 manholes in Fairfax and each manhole is viewed every 3-5 years depending on the age and material of the pipe and whether the pipe has already been rehabilitated. There are some county sewer lines that are inspected quarterly or even monthly if necessary.  Neighborhoods built after 1970’s contain PVC pipe are checked less frequently because PVC has been demonstrated to last longer, 50-100 years in other parts of the country.  

The sewer system in Fairfax County was built out over the last 70 years as the county developed. Every year Fairfax County spends $6,000,000 in a planned program to rehabilitate 125,000 feet of pipe within the sewer system. Rehabilitation of sewer pipes involves sliding a resin impregnated fiberglass liner into the pipe at a manhole and using steam to rapidly cure the lining and have it bond with the existing asbestos cement (transit) or cement pipes. After the lining is in place the connections of the lateral sewer pipes is cut out. The curing process leaves an indentation where the lateral joins the sewer main and the vendor the county hires to do the work cut out the “coupons” to open the laterals. Rehabilitating a sewer main takes just one day from early morning until late afternoon and then the residences or businesses can go back to normal use of water. The sewer system in Fairfax is fairly young, and the current program of planned replacement is a fraction of a percentage of the piping in the system.  Nonetheless, during the last fiscal year ended July 1, 2012 Fairfax had only 19 backups and manhole overflows in the Fairfax owned system and 2 pipe collapses attributable to maintenance issues.

You might be thinking that there were more sewage backups in Fairfax during the past year after all, how would the rooter companies (like Rotor-Rooter and Rescue Rooter) make a living if sewage did not backup with certain regularity. It is true, there are more sewage backups in Fairfax, but they do not belong to the county. In Fairfax County there is private ownership of the lateral sewer lines from the building until it ties into the county sewer main. The homeowner or building owner in Fairfax is responsible for the entire lateral line (even past the property line) and the connection. So, when sewage backs up into your house and you call the county they will dispatch a crew to open the manhole on your street and see if the sewer main in blocked. Chances are that the sewer main is clear and Fairfax will tell you the problem is yours. They do not count these backups in their statistics.

In the sections of the county that developed after World War II and until 1970 Orangeburg pipe was used for the sewer laterals. Orangeburg pipe was piping made by Orangeburg Manufacturing Company of  ground cellulose fibers bound together with a special water resistant adhesive, and then impregnated with liquefied coal tar- basically tar impregnated cardboard pipes. The joints were made with couplings of the tar impregnated cardboard. Over time, the pipe have proven susceptible to deformation and root intrusion two things when combined with a lot of grease cause sewer backups. This year could be a very bad year for sewer backups into homes because during droughts tree root seek the moisture in the sewer pipes and infiltrate the pipes especially the old Orangeburg pipes. Because these sewer laterals are essentially made of cardboard, using a spinning rotor to cut out the roots is likely to ultimately abrade away the pipe wall, but can be done several times before the pipe fails.

The grease from holiday cooking combined with the root infiltration from a dry summer are likely to result in a sewer backup in your home at the most inopportune time. The worst maintained pipes in Fairfax County are the laterals owned by the property owners. It is very expensive to replace your lateral sewer pipe because the homeowner not only has to trench their yard but also cut the roadway and curb to replace the pipe and connect a new lateral to the sewer main. After the pipe repair is complete the property owner is responsible for repairing the road and curb. In the late 1960’s PVC (polyvinyl chloride) pipe replaced Orangeburg pipe. There are a lot of sewer backups in Fairfax and there are other problems caused by the historic residential construction. The sanitary sewer system in Fairfax is an entirely separate system than the storm sewer system, but there are still storm related increases in flow due to the infiltration of stormwater into the sewers and flow of stormwater into drains and sump pumps illegally discharging in the sanitary sewer system. That excess flow can result in more than 150% of the average daily sewage flow.  When many of the homes in Fairfax were built, it was perfectly legal to connect basement drains to the sewer lateral and use the sewer system to transport the groundwater out of the neighborhood. Excess flow, root infiltration in the pipe and grease build up will ultimately cause the lateral to rupture. So, the County’s advice to “Can the Grease” is good advice for homeowners to save yourself some money and prevent sewer backups in your home.

I would like to thank Irene Haske and Tom Russell of Fairfax County Virginia Department of Public Works and Environmental Services for their time and help in researching this topic.    

Recycled Water in Fairfax, Virginia

All the water that ever was or will be on earth is here right now. More than 97% of the Earth’s water is within the in oceans. The remaining 2.8% is the water within the land masses, as groundwater, rivers, streams, lakes, and within the ice caps and glaciers (over 77% of fresh water is currently frozen). Only a fraction of water falls as rain each year to make the rivers flow, recharge lakes and groundwater. The water on earth never rests, it is constantly moving within the hydrologic cycle along various complex pathways and over a wide variety of time scales. Water moves quickly through some pathways -rain falling in summer may return to the atmosphere in a matter of hours or days by evaporation. Water may travel through other pathways for years, decades, centuries, or more. As the demand for water grows in our population centers, we are straining to meet the demand. Even in generally water rich areas there are limits to the availability of water and United States has slowly and quietly begun to address the availability of water by recycling the water.

Direct water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin (referred to as ground water recharge) and less commonly returning the water directly to reservoirs. Since 1978, the upper Occoquan Sewage Authority has been discharging recycled water into a stream above Occoquan Reservoir, one of the two potable water supply sources for Fairfax County, Virginia. Recycled water has been part of the Occoquan supply for 34 years and chances are if you are in Fairfax, parts of Prince William and Loudoun counties you have been regularly drinking recycled water. Noman M. Cole, Jr., a very forward thinking engineer, developed the Occoquan Watershed Policy in 1971. This policy was the acknowledgment that to continue supplying the region with drinking water, the Occoquan Reservoir would be used both for wastewater disposal and public water supply. To do this and protect public health the Occoquan Watershed Policy not only specified the type of waste treatment practices that would have to be adopted on a basin-wide scale, but it provided for an on-going program of water quality monitoring to measure the success (or failure) of the waste water treatment. This resulted in the construction of the Upper Occoquan Service Authority, UOSA, advanced wastewater treatment plant with tertiary treatment to replace the eleven small secondary treatment plants.

Wastewater treatment within the basin would have three stages of treatment, primary, secondary and tertiary or advanced treatment.  Primary Treatment consists of sedimentation and screening of large debris using screens and large settling tanks. Until 1960’s primary treatment was the only form of sewage treatment in most places. Secondary treatments usually include biological and/or chemical treatment. One of the most common biological treatments is the activated sludge process; in which primary wastewater is mixed with bacteria that break down organic matter and cleans the water. Oxygen is pumped into the mixture. A clarifying tank allows sludge to settle to the bottom and then the treated wastewater moves on for tertiary treatment. Coagulation, filtration and disinfection take place in tertiary treatment. A coagulant is added, UOSA uses the high-lime process to reduce phosphorus to below 0.10 mg/L. This process also serves as a barrier to viruses, captures organics leaving secondary treatment, and precipitates heavy metals and other suspended particles. The UOSA permit requires total suspended solids, TSS, below 1 mg/L and chemical oxygen demand, COD, below 10 mg/L. To meet these stringent levels, multimedia filtration and activated carbon are used. Filtration removes organic matter, microorganisms and mineral compounds, and excess nutrients. The final barrier to pathogens is a chlorination and dechlorination process. UOSA uses sodium hypochlorite and sodium bisulfite. UOSA is has an expansion program underway to expand capacity to 54 million gallons a day, but according to 2012 Fairfax County disclosures, the plant currently operates closer to an average of just over 13 million gallons a day.

After disinfection the reclaimed water is released to the watershed cleaner than the rest of the river, according to Dr. Tom Gizzard ofthe Occoquan Watershed Laboratory. Financed by the wastewater treatment plants and Fairfax Water, the Occoquan Watershed Laboratory (OWL), was established by the Virginia Polytechnic Institute Department of Civil Engineering. The laboratory began its Fairfax operations in 1972, and has conducted comprehensive studies of receiving water quality, and effects of the waste water treatment effluents for 40 years. The current Director of the Laboratory is Dr. Tom Grizzard, professor of Civil Engineering at Virginia Polytechnic Institute and State University (Virginia Tech). When I spoke to Dr. Grizzard he pointed out that the water released into the Occoquan is “highly reclaimed wastewater” and not sewage effluent. There is a difference and Dr. Grizzard and the OWL staff make sure of it.

The Occoquan Watershed Policy is the oldest and largest reservoir augmentation program in the county and the second largest water recycling program in the country. The largest water recycling or reclamation program in the country and in the world belongs to the Orange County Water District and the Orange County Sanitation District jointly owned and developed the Groundwater Replenishment (GWR) system, the world’s largest water purification plant for groundwater recharge. The GWR System diverts secondary treated sewer water and purifies it through a series of tertiary treatments: microfiltration, reverse osmosis, ultraviolet disinfection and hydrogen peroxide. The cleaned water is returned to the groundwater basin to increase both the water supply and quality rather than discharging the treated sewer water to the ocean. The additional treatment of the wastewater is much cheaper that desalinization and makes the groundwater use sustainable-utilizing the groundwater basin as a reservoir.

In Fairfax County Virginia, water is withdrawn from the Potomac River and the Occoquan Reservoir and filtered, cleaned, disinfected and delivered as drinking water to the homes and businesses throughout the county (and in parts of Prince William and Loudoun Counties). Waste water from toilets, sinks, drains is collected by the sewer systems and six waste watertreatment plants that serve some portion of Fairfax County.  On average, Fairfax County uses 160 million gallons of drinking water per day from both the Corbalis plant and the Griffith plant drinking water plants. The combined total capacity of both plants is 345 million gallons/day. The drinking water systems are sized to deliver the peak demand on a 100 degree day when everyone is doing laundry and watering their lawns and everything else we do with water on hot summer days.  Most of that water (except what is used to irrigate landscaping) finds its way to a waste water treatment plant within the region. The wastewater processed in Fairfax County is fully treated and released into the river and streams of the Potomac watershed. (We will ignore the issues currently being addressed at Blue Plains.) To ensure the continuation of water supply during droughts, Fairfax is party to a low flow allocation agreement with the members of the Interstate Commission on the Potomac River Basin, ICPRB. In addition, Fairfax bought the rights to 14 billion gallons of water from the Jennings Randolph Reservoir. On an ongoing basis ICPRB coordinates Fairfax Water’s low flow water withdrawals between the Potomac and Occoquan. The Occoquan Reservoir contains 11 billion gallons that receives both natural river flow and about 13 million gallons of reclaimed water daily.

From Fairfax County

Noman M. Cole, Jr. Pollution Control Plant (named in honor of the engineer) is now engaged in a direct water recycling program, reusing treated wastewater for landscape irrigation and industrial processes. The Noman Cole plant releases its reclaimed water to Pohick Creek. Now the plant is engaged in the Water Reuse Project also known as the Purple Pipe Project, to directly reuse some of the water. (The pipes are colored purple to designate the water as non-potable.) The Purple Pipe project has completed the first phase of the project and is delivering 1.4-1.6 million gallons of fully treated waste water to the Covanta Fairfax, Inc. Resource Recovery Plant and Laurel Hill Golf Course via a recently constructed 5 mile purple pipeline, two large pumps, instrumentation and hypochloride disinfection. The Laurel Hill Golf Course will use the water to augment the on-site irrigation lake during the summer. Due to recent rains, the demand for water by the golf club is limited, but according to Michael McGrath the Director, Wastewater Treatment Division, Department of Public Works and Environmental Services, for Fairfax County, the Laurel Hills Golf Club can draw up to 27 million gallons a year of reclaimed water from the Noman Cole Plant. The Covanta Resource Recovery Plant is allowed to use up to 560 million gallons a year of Purple Pipe Water to irrigate the adjacent athletic fields and other purposes. The Noman Cole plant discharges and average of 45 million gallons a day to Pohick Creek, so this is just a small fraction of the daily flow.  The reclaimed water from Noman Cole makes up a significant flow to Pohick Creek so that there is a minimum environmental flow that should continue, but there is opportunity for growth in the Purple Pipe Project.

The project, which began in 2009, cost $16 million for the first phase (or about $600 per foot) with $6.5 million in funding coming from the federal stimulus funds through the American Recovery and Reinvestment Act, and the remainder was paid for by Fairfax county through a loan from the Virginia Department of Environmental Quality Clean Water Revolving Fund Loan Program. In the first partial year of operation the project will produce about 20,000 credits for Noman Cole Plant in the Virginia Nutrient Trading Program in addition to the reduced cost water. Nutrient trading programs provide wastewater treatment plants with flexible options for meeting and maintaining permitted nutrient load limits, but also could be used to meet the approximately 25% reduction in nutrients required under the federally mandated Chesapeake Bay TMDL. A nutrient credit is a reduction of one pound of nitrogen and worth (at the current time) $2. Though the first phase of the Purple Pipe Project will generate more credits next year, still at $2 per credit plus the price received for water and costs or $600 per foot there is virtually no way for Fairfax to utilize Purple Pipe to meet the TMDL goals or increase water supply without a significant rate increases for water and large volume users. If using reclaimed water is necessary for the region to maintain its quality of life, the cost of water will have to rise to cover the costs because we are already using all the cheap water.

The numbers break down like this: this project would have to produce cash flow of about $918,000 per year (rather than the projected under $200,000 for water and nutrient credits) to pay for the $16,000,000 cost at 3% interest (current AAA interest for 20 year bonds is above 3%) over 25 years.  (Though for this project the $6.5 million from the federal stimulus funds does not have to be repaid.) The Purple Pipe project is a very cool project, but at the current cost of water the capital costs are prohibitive. Or maybe, we've just had a glimpse of the marginal cost of water.

  

The Rural Crescent an Essential Part of Our Green Infrastructure

At the regular March meeting of the Prince William County Board of Supervisors while considering requests for exceptions to the comprehensive plan, Supervisor Martin Nohe supported by the other county Supervisors seemed to feel that it was time to reconsider some of the planning and development decisions that had been made in the past and asked for staff to produce an analysis of the usefulness of the Rural Crescent in achieving those goals. The request was made by Supervisor Nohe to Prince William County staff and noted in the minutes.

The Rural Crescent was created in 1998 and has been chipped away at with exception requests every year. Higher density development means money to developers and landowners. There is much passion when money is on the table. The Rural Crescent in Prince William County was originally intended as an urban growth boundary for the county designed to preserve our agricultural heritage and force redevelopment along the Route 1 corridor rather than Greenfield development in the remaining rural areas. Maintaining the emphasis on redevelopment of areas with preexisting infrastructure would allow Prince William County to improve storm water management, achieve nutrient and sediment reductions for the EPA mandated TMDL, revitalize older areas of the county and preserve the Greenfields. The Rural Crescent may have started with different intentions; but today the Rural Crescent is about water, groundwater and ecosystem preservation.

Supervisor Nohe’s interest in transforming the 80,000-acre rural crescent where development has generally limited to one home per 10 acres with no access to public sewer is of great concern. Even though I believe that Supervisor Nohe is interested in moving towards sustainable community concepts, high density communities utilizing the strategies of Low Impact Development, LID, which include dedicated open space will not guarantee the preservation of our ecosystem and water. When development disturbs more than 10% of the natural land by covering surfaces with roads, driveways, walkways, patios, and homes the natural hydrology of the land is disturbed, irreparably disturbed. These developments while much better than traditional developments still disturb more than half the land area by significantly increasing allowed building density.

 While it has been demonstrated that LID strategies can reduce the impact of development, there is no demonstrated strategy of how communities can control and maintain natural storm water features and preserve and maintain the safety and ecology of preserved open space. There are no regional groundwater studies, regional ecosystem pans and no budgets for maintaining the open space.  Access control and prevention of improper use (underage drinking, drug use and sale,  other illicit activities, dirt bike racing) addressing deer population management and hunting adjacent to high density homes, litter and trash removal, maintenance of natural landscapes and supervision all cost money and time. No legal structures exist that guarantee open spaces will not be developed in the future to defray maintenance costs.  Why the Rural Crescent was formed is less important than understanding that the Rural Crescent provides a significant portion of our green infrastructure to our community.  

Green infrastructure connects the still intact habitat areas through a network of corridors that provide for wildlife movement and trails as well as pathways for pollinators. Maintaining intact, connected natural landscapes is essential for basic ecosystem and watershed preservation to ensure that there will always be clean air and water in Northern Virginia. Maintaining a tree canopy and controlling runoff to prevent stream bank erosion and water quality impairments and maintaining adequate water flows through groundwater and surface recharge are vital to ensuring safe water supplies, water recreation and the ecological integrity of the region. The Northern VirginiaRegional Commission (NVRC) has developed a Conservation Corridor PlanningProject which is a regional effort to identify essential green infrastructure and help area governments to avoid the mistakes of the past and maintain the few remaining green corridors along the rivers and reservoirs in Fairfax and integrate green infrastructure planning into the future development planning of Prince William and Loudoun counties.  

According to NVRC there are three priority regional conservation corridors in Prince William County.  Bull Run Mountain and Catoctin Mountain corridor is a north-south corridor connecting the foothills of the Blue Ridge Mountains in Northern Virginia.  The corridor provides significant intact habitat for Northern Virginia wildlife.  North of Leesburg, the corridor is the karst terrain of Loudoun underlain by limestone, and highly susceptible to pollution that provides a significant ground water recharge.

Karst aquifers are highly vulnerable to contamination. This vulnerability results from: sinkholes, widened flow paths, and rapid velocities of ground water and contaminants. Contaminants can be transmitted quickly from entry in a sinkhole to wells and springs in the vicinity. Sinkhole creation, sinkhole flooding, and groundwater contamination are the major hazards associated with karst terrain, and unlike other natural hazards they are chronic in nature. South of Route 50 the Bull Run Mountain ridge is the location of a significant area of recharge for the groundwater that ultimately maintains and feeds Bull Run and the Occoquan River. This area is part of a fractured rock system with limited overburden and no natural attenuation. A polluted plume could be carried for miles without dilution.

The second priority conservation area is begins at the Bull Run Mountains and heads east across Route 15 to Manassas covering the land between Route 50 and 29 to the confluence of the Occoquan River with Belmont Bay. This corridor is rich in water and environmental resources that ultimately deliver drinking water to over one million Northern Virginia residents. The Occoquan Reservoir, one of the country’s first water reclamation facilities where sewage treatment water is returned to provide water recreation. The western portion of the area is part of the Culpeper Basin Important Birding Area and the Culpeper Basin Groundwater Aquifer. Preventing water contamination and ensuring adequate groundwater recharge are vital to ensuring safe water supplies, recreation opportunities and the ecological integrity of the region.

The third priority conservation area is the Potomac Gorge and Quantico Corridor, the greenbelt that connects Prince William National Forest Park with Manassas Battlefield. This area includes large tracks of undeveloped private land. The western portion of the Rural Crescent was not identified by NVRC as a high priority conservation area because they failed to consider the importance of the groundwater aquifer. The Culpeper basin is part of a much larger PiedmontGeologic Province and has only begun to be studied thanks to the carefulgroundwater measurements taken by Loudoun County as excessive development ofthe western part of the county began to impact water supplies.  Groundwater quantity and quality in our region impacts not only groundwater wells, but stream flow and recharge to the surface water. In short all the drinking water in Prince William County. Groundwater recharges at various rates from precipitation and other sources of infiltration. The recharge is not spread evenly across the land. Pave over the land, change surface flow and infiltration and groundwater recharge are reduced.

Important regional waterways, such as Goose Creek, Bull Run, the Potomac River and Occoquan Reservoir thrive because they are shaded by trees and vegetation that filter stormwater, prevent erosion, and facilitate ground water recharge and moderate temperatures. Green infrastructure maintenance ensures the forested buffers are maintained and enhanced over time, protecting public health and water quality. Maintaining and enhancing forested buffers near Northern Virginia’s waterways requires focus on how to maintain and protect these ecological resources. The EPA has identified nitrogen, phosphorus and sediment as the three primary pollutants that must be reduced to restore the health of the Chesapeake Bay and its tributaries. They have mandated to Virginia and the other Chesapeake Bay Watershed states and Washington DC an approximate 25% reduction in these pollutants. A wide range of approaches can address these impairments, including reducing runoff and restoring stream banks and buffer areas. Adding more development in the Rural Crescent will not reduce the current level of sediment and nutrient pollution, and will not assure our water resources and ecology.