Hetch Hechy Valley Restoration Plan on Ballot for November

Picture from SF PUC web site

The Hetch Hetchy Valley is a glacier-carved granite canyon located in Yosemite National Park. Though once described by John Muir as a smaller version of the Yosemite Valley it is currently dammed and used as a reservoir and hydroelectric generator by the City of San Francisco. After obtaining more than 15,000 signatures, a group whose ultimate goal is to restore the Hetch Hetchy Valley has put an initiative on November’s ballot. The initiative would require the city to create a new master plan for their water system based on draining the reservoir and returning Hetch Hetchy to the national park service.

The initiative requires that the water plan include water recycling, water reclamation, conservation, improved storm water capture and increased development, including recharge capability, of groundwater sources and replacing the hydropower from the loss of the dam with solar and wind renewable sources of power. In addition, the plan would have to develop other sources of water supply because all the studies cited on both sides of the argument indicate that the water supply will fall short.

The Hetch Hechy system consist of much more than the reservoir created by the O’Shaughnessy Dam. The system consists of Hetch Hechy Reservoir, Cherry Reservoir and Eleanor Reservoir a portion of the New Don Pedro Reservoir as well as other small surface reservoirs of various size and significance and five groundwater basins.  The stored water in the system is transported to the cities, towns and farms supplied by the system via the Hetch Hetchy Aqueduct, the California Aqueduct, the Delta Mendota Canal, the South Bay Aqueduct, and the Pacheco Tunnel. 

Taken from BAWSCA

Now developing a plan for removing O’Shaughnessy Dam to restore Hetch Hetchy Valley is on the ballot. While many will dismiss the idea as preposterous, enough studies have been done and computer models created that it is fairly certain that the idea is only extremely costly and will reduce somewhat the reliability of the water supply. Billions upon billions of dollars depending on how certain you want your water supply to be, and remember these are costs that would have to be borne by San Francisco water rate payers not the state taxpayers or national taxpayers.

First of all, the inescapable regulatory costs- these costs are certain. While O’Shaughnessy Dam has storage capacity of 360 thousand acre-feet (taf) and the Hetch Hetchy system stores 2,000 taf of water a year, its value is more than that modest amount of water storage. The O’Shaughnessy Dam and Hetch Hechy reservoir provides water storage, hydropower generation, and some flood control, but primarily its value is that water from O’Shaughnessy Dam has filtration avoidance status. Without O’Shaughnessy Dam, the San Francisco Public Utilities System, SFPUC, would have to build a water treatment plant for filtration. New York is currently completing the construction of a new filtration facility to treat the water from the Croton Water System. Though it was originally estimated to cost $950 million, to date its cost has been $2.8 billion. This would translate to a cost of $5-$6 billion to build a filtration plant for SFPUC. Then on top of the construction costs and interest payments, there are the operating costs. Estimates have ranged from $13 million (estimated in 2000) to $20 million annually.

In addition, to replace the storage various solutions have been suggested the most obvious one being increasing the height of the Don Pedro Reservoir to increase its storage. This would require a major construction project. I could find neither feasibility studies nor estimates on the costs associated with that project- the dam cost about $100 million in 1967. Would it cost five times, ten times to expand it now? There is very little recent dam expansion or building data to use to estimate the cost.  However, to effectively replace the Hetch Hetchy storage an inter-tie linking the New Don Pedro Reservoir to the Hetch Hetchy Aqueduct would be necessary to avoid releasing the water through the Delta (and we know how that works out). It would probably cost a couple of billion or more to take care of those two items.

The ballot measure calls for including water recycling, water reclamation, and improved storm water capture in the plan. The reason is there is virtually no other way to obtain enough water for the Bay Area without it. It should be noted that at some time in the future these water reuse strategies will be necessary if the population of the Bay Area continues to grow. There are 993 miles of combined sewers in San Francisco, which collect sanitary sewage from toilets and drains in apartments, homes, schools, offices and other businesses, and street runoff throughout the city. The Water Sustainability and Environmental Restoration Plan would require rebuilding the sewer system to separate the storm water system from the sanitary sewer system and improving the water treatment and recovery of the wastewater treatment plants in San Francisco.

The two major waste water treatment plants that serve the city of San Francisco are the Southeast Water Pollution Control Plant in Bayview built in 1950’s and the Oceanside Water Pollution Control Plant built in 1993. On a dry day the San Francisco combined sewage system treats about 80,000,000 gallons a day of sanitary sewage.   The San Francisco Wastewater Treatment plants are not designed to do any more than screen out trash, skim off scum and grease and use bacterial action to digest toilet paper and bio-solids. Pharmaceuticals, pesticides, hydrocarbons and anything else the residents can think to pour down the drain or dump into the storm drains will either clog the system or be released into the Bay or Ocean. If we are to reuse this water additional treatment would be necessary. Pharmaceuticals, pesticides and other chemicals pass through the system untreated at this time additional treatment and control would be necessary to reuse this water. The cost of these systems would be dependent on the level of treatment desired to drink that water. Washington DC is currently engaged in a plan to upgrade their Blue Plains Wastewater Treatment system that discharges to the Potomac their program is estimated to cost $7.8 billion.

CALVIN (CALifornia Value Integrated Network) is an economic-engineering optimization model of California’s inter-tied water management system. It was developed by Jenkins et al. at the University of California, Davis and has been used to make many of the estimates for feasibility for removal of the O’Shaughnessy Dam and restoration of the Hetch Hetchy valley. CALVIN uses 72 years of monthly historical data to represent future hydrology. They use data from water year 1922 to water year 1993. This period includes the droughts of, 1929-1934, 1976-1977, and 1987-1992, which were some of the worst on record. However, this period of time may not be representative of the severity and duration of droughts and what rainfall will look like in the next decades. Australia’s experience with drought duration last decade should have taught us that.  The driest year in the data was 1924 when the state average rainfall was only 10.50 inches, but in that year the San Francisco Bay region was drier than the rest of the state. The future might hold a worse or longer drought or a regional drought.

An important limitation with CALVIN is perfect foresight; CALVIN knows when the droughts are going to happen and how long the droughts will be. This allows the model to be proactive in preparation for droughts, reducing water scarcity and associated costs. In addition, the model assumes that unlimited amounts of water can be purchased from others (farmers) to make up any shortfall and that there exists a pipe linking the New Don Pedro Reservoir to the Hetch Hetchy Aquitard.

This ballot measure is for the development of the Water Sustainability and Environmental Restoration Plan. This plan has the potential to be forward looking and develop an integrated and robust design for the water and wastewater systems of the Bay Area for the next century. The cost of developing this plan is limited to 0.5% of funds previously authorized by voters for the Water System Improvement Program, WSIP. That translates to $23 million dollars of the $4.6 billion WSIP just to develop a plan that must be completed by November 2015 “in time for the San Francisco Board of Supervisors or a group of citizens to propose a charter amendment to be voted on at the November 2016 election, which if passed would authorize implementation of the plan.”

Even this ballot measure is a significant decision for the residents of San Francisco, and about much more than restoring the Hetch Hetchy Valley. This is a first step on the road towards rebuilding the entire, water storage, treatment and sewer system for the Bay Area  as well as replacing the hydroelectric power from O’Shaughnessy Dam with other (hopefully) renewable power. The full implementation of the plan could easily cost San Francisco rate payers $10-$20 billion for infrastructure. I assume that funds to restore the Hetch Hetchy Valley would come from donations or the federal park service. The $23 million that the ballot measure authorizes for the study may not be enough to develop a fully integrated and workable plan, for transport, sewers, water treatment, water recycling and power generation let alone hold the necessary public hearings and outreach in San Francisco.    

Wastewater Treatment in San Francisco and the SF PUC

The San Francisco Public Utilities Commission (SFPUC) is a department of the City government that provides: Regional and local water, Wastewater (collection, treatment and disposal), and Power. I spoke with Idil Bereket, Public Relations Officer for the Wastewater division to gain a fuller understanding of the wastewater programs after seeing the “only rain down the drain” signs around the city and chatting up an employee testing wastewater at Saint Francis Hospital.

Treating waste water and collecting storm water are essential city services, but this function also requires that the SFPUC work to educate the public to prevent pollution and limit the trash, contaminants and waste that enters the system. The SFPUC operates and maintains 993 miles of combined sewers, which collect sanitary sewage from toilets and drains in apartments, homes, schools, offices and other businesses, and street runoff throughout the city. Most of San Francisco operates under a combined sewage storage and treatment system. That means for most of the city, all sanitary sewage and stormwater is collected into the same pipes and catch basins and treated in the three treatment plants. There are a few areas of the city that were developed with a separate stormwater sewage system and those are controlled and discharge separately to the Bay.

The SFPUC operates three twenty-four hour a day waste treatment plants and one occasional plant that is used during rainy weather when the combined system collects more water. San Francisco is unusual in that it operates with a combined sewer system that collects and treats both wastewater and stormwater in the same system. Though stormwater is relatively clean, it does wash street pollutants into the sewer system that should not be directly released into the Bay or the Pacific. However, the processes needed to address street pollutants-motor oil, pesticides, metals, dirt and litter are different from the processes to separate toilet paper and sewage, and the pollutants of concern are different. That means the rain that runs off streets and buildings gets treated at the wastewater treatment plants just like sanitary sewage. That is expensive. Rain water is relatively clean and could be treated with a filter and oil and grease separators, but combining the stormwater with the sewage creates a large volume of water that goes through the wastewater treatment plants.

The smallest of the waste treatment plants is the Treasure Island plant that serves only Treasure Island and will be ignored for the rest of the discussion. The two major waste water treatment plants that serve the city of San Francisco are the Southeast Water Pollution Control Plant in Bayview built in 1950’s and the Oceanside Water Pollution Control Plant built in 1993. On a typical day the Southeast Water Pollution Control plant treats about 80% of the wastewater in the city. On a dry day the San Francisco combined sewage system treats about 80,000,000 gallons a day of sanitary sewage, during storms the treatment load can increase to up to 500,000,000 gallons of combined sewage. That six fold increase in water volume is more than can be handled by using the North Point Weather Treatment Plant.

What makes the system so expandable is the system of storage/transport boxes. The storage/transport boxes are huge underground rectangular tanks or tunnels that surround the City, the SFPUC describes it as a moat, a fitting image. The storage/transport boxes catch the combined stormwater and sewage as it overflows the sewer system, but before it reaches the shoreline of the Bay or Pacific Ocean. The storage/transport boxes have a total storage capacity of 200,000,000 gallons and hold stormwater and sewage for later treatment at wastewater treatment plants. If the capacity of the storage/transport boxes should be exceeded, the wastewater including sewage would be released into the Bay or the Pacific Ocean.

The storage/transport boxes provide the fist step of treatment, settling and screening of floatable materials inside the boxes. This step is equivalent to primary treatment that takes place at the wastewater treatment plants. When wastewater reaches the wastewater treatment plant, it passes through a screen used to remove large objects and debris. (You would not believe some of the debris which gets into the system despite the “only rain down the drain” signs.) Then the wastewater enters large settling tanks where heavier solids settle to the bottom, and floatables like oil and grease are scraped off the top.

Secondary treatment is bacterial digestion of organic waste. This process is enhanced by using blown oxygen to increase microorganism population enhancing the speed that the bacteria consume organic material in the wastewater. Afterwards, the wastewater is put into a second round of settling tanks where the microorganisms are separated from the purified water. Treated wastewater, is disinfected before being discharged into the San Francisco Bay from the Southeast Plant and into the Pacific Ocean from the Oceanside plant where the high salt concentration and cold temperatures help to kill any remaining bacteria. Effluent at North Point Facility is also disinfected before being discharged into the San Francisco Bay.

Sludge separated from wastewater during primary and secondary treatment is further processed on a “Gravity Belt Thickeners” to remove more water from the sludge. The thickened sludge is pumped into enclosed digester tanks. It is mixed for 15-25 days and heated at a constant temperature of 95 degrees Fahrenheit to allow anaerobic bacteria to break down remaining organic material in the sludge. Once treated, sludge is transformed into bio-solids. San Francisco produces 160,000,000 pounds of bio-solids every year that are recycled as fertilizer. The methane given off by the anaerobic bacteria is captured and used to power the system heaters.

The wastewater treatment system is not designed to do any more than screen out trash, skim off scum and grease and use bacterial action to digest toilet paper and bio-solids. Pharmaceuticals, pesticides, hydrocarbons and anything else the residents can think to pour down the drain or dump into the storm drains will either clog the system or be released into the Bay or Ocean. Cooking grease hardens when it cools in the sewer pipes. This can constrict the sewer pipes or form blockages that increasing pressure and often causing sewer pipe failure. Pharmaceuticals pass through the system untreated and pollute the Bay and estuary habitat. Pesticides and other chemicals can damage the bacterial habitat preventing adequate treatment of the sewage or be released to the Bay. As the SFPUC points out with their educational campaign, water pollution prevention begins with using your toilet to dispose of the three “P’s” (do you really need me to tell you?), recycling cooking oil, and remembering that everything that goes down the drain goes right out into the bay. A toilet is not a trash can and neither is a storm drain. To optimize the operations of the wastewater system at least expense, utilize rain barrels and cisterns to reduce overall flow to the system, and only allow the intended wastewater to enter toilets and drains and only rain should go down the stormwater drains.

The SF PUC has labeled all 23,000 stormwater drains to remind citizens not to use the storm drains as a trash can or disposal drains. According to Idil Bereket of the SFPUC, these little reminders have been effective in reducing dumping into the storm drains. In addition, the SF PUC runs SF Greasecycle, a citywide project that collects used cooking oil primarily from restaurants and converts it to bio-fuel for biodiesel vehicles. In the past year over 124,000 gallon of used cooking oil were collected and recycled. There is a small program that collects consumer generated cooking oil at several retail outlets and at holiday drop off points. Finally, the Rainwater Harvesting Program, subsidizes rain barrels and cisterns for city residents. Last year they sold 38 cisterns and 192 rain barrels. This diverted over 21,000 gallons of rainwater from the combined sewer system.