Final Rainwater Harvesting

Transcription

1 Final Rainwater Harvesting Exposition Rail Operations and Maintenance Facility Santa Monica, California Prepared for: Exposition Metro Line Construction Authority Prepared by: W2 Design, Inc. 50 S. De Lacey Avenue Suite 100 Pasadena, CA /28/13

2 Final Hydrology Analysis Report DELARATION OF RESPONSIBLE CHARGE I HEREBY DECLARE THAT I AM THE ENGINEER OF WORK FOR THIS PROJECT. THAT I HAVE EXERCISED RESPONSIBLE CHARGE OVER THE DESIGN OF THE PROJECT AS DEFINED IN SECTION 6703 OF THE BUSINESS AND PROFESSIONS CODE, AND THAT THE DESIGN IS CONSISTENT WITH CURRENT STANDARDS. TONY K. WONG R.C.E DATE: 1/28/2013 Exposition Metro Line Construction Authority 1 W2 Design Inc.

3 Expo Rail Operations and Maintenance Facility TABLE OF CONTENTS EXECUTIVE SUMMARY... 4 SECTION 1: INTRODUCTION... 5 TANK SIZE... 5 REGULATIONS... 6 USES... 6 TANK LOCATION... 8 CISTERN OPTIONS SECTION 2: BASIS OF ANALYSIS METHODOLOGY RAIN DATA WATER DEMAND BY USE SECTION 3: COST ANALYSIS SANTA MONICA WATER COSTS LIFE-CYCLE COST ANALYSIS SECTION 4: OPTIONS CONSIDERED ,000 GALLON (107,000 CF) TANK ,000 GALLON (14,000 CF) TANK INCREASE SITE PERVIOUS AREAS PAY URMP FEE Required Storage for Reuse/Infiltration In Lieu Fee Calculation SECTION 5: DESCRIPTION OF THE EXPO OMF SYSTEM SYSTEM MAINTENANCE WATER QUALITY SECTION 6: BENEFITS TO RAINWATER HARVESTING SYSTEM BENEFITS Rain Water Harvesting LEED Points Hedging Future Water Costs SECTION 7: CONCLUSION APPENDIX A LA COUNTY DEPARTMENT OF PUBLIC HEALTH RAINWATER HARVESTING MATRIX APPENDIX B RAIN DATA APPENDIX C RAINWATER HARVESTING LEED CREDITS ARTICLE Exposition Metro Line Construction Authority 2 W2 Design, Inc.

4 FIGURES Expo Rail Operations and Maintenance Facility FIGURE 1 - NON-POTABLE CISTERN USES SITE PLAN... 7 FIGURE 2 - CISTERN LOCATION EXHIBIT... 9 FIGURE 3 - CISTERN TYPES FIGURE 4 - SITE AREAS FIGURE 5 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - ALL USES FIGURE 6 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - NO WASH BUILDING FIGURE 7 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - IRRIGATION ONLY FIGURE 8 - DAILY CISTERN VOLUME (104,000 GALLON TANK) - 50% INCREASE IN IRRIGATION DEMAND FIGURE 9 - RAINWATER HARVESTING SYSTEM TABLES TABLE 1 - CISTERN LOCATION COMPARISON TABLE 2 - CISTERN TYPE COMPARISON TABLE 3 - IRRIGATION DEMAND TABLE 4 - INDUSTRIAL WATER DEMANDS TABLE 5 - LIFE-CYCLE COST ANALYSIS Exposition Metro Line Construction Authority 3 W2 Design, Inc.

5 Expo Rail Operations and Maintenance Facility EXECUTIVE SUMMARY In order to satisfy local stormwater regulations, CalGreen and LEED requirements, and project goals, the project design team investigated rainwater harvesting alternatives for the EXPO Rail Operations and Maintenance Facility. Initial investigations looked into sighting or placement of a cistern, sizing of the cistern, and cistern materials. Possible uses were also investigated. The team researched and calculated water demands from various uses. Lastly, manufacturers were contacted to determine preliminary pricing of various systems. The cost data is included in this report. A life-cycle cost analysis is also included herein. Based upon the data gathered, a tank of 800,000 gallons (107,000 cubic feet) has been designed for the maintenance facility. A precast concrete or high-density polyethylene pipe tank can be installed by the contractor provided that they meet the performance criteria outlined in the project specifications. The project specifications outline the performance criteria for the cistern. The cistern tank will be located in the projects easterly parking lot which is adjacent to the outfall and not under any track facility. The total system to procure and install will cost less than paying the City of Santa Monica s Urban Runoff Maintenance Program (URMP) fee, even when maintenance costs are included and brought to a present value. A life-cycle cost analysis was prepared and compared to a no-build option of paying the URMP fee. The Rainwater Harvesting system will require minimum maintenance. This includes cleaning of the hydrodynamic separator and filter inserts annually, cleaning of the cistern tank once every five years and maintaining pumps and controls as needed. Exposition Metro Line Construction Authority 4 W2 Design, Inc.

6 SECTION 1: INTRODUCTION Expo Rail Operations and Maintenance Facility Stormwater Treatment has become a greater concern throughout the U.S. since the enactment of the Clean Water Act (CWA) with the amendment of the National Pollutant Discharge Elimination System (NPDES). Los Angeles County developed their Standard Urban Storm Water Management Plan (SUSMP) program to comply with the CWA. The City of Santa Monica has opted for additional requirements due to concerns over recreational ocean swimming after rain events. One of the sustainability goals for the EXPO Rail Operations and Maintenance Facility (OMF) is to have zero runoff of stormwater, which is the reason the design team has chosen to investigate stormwater reuse options. Additionally, the City of Santa Monica has established a city ordinance that requires development and redevelopment projects to comply with the Urban Runoff Mitigation Plan (URMP). The ordinance requires that the first ¾ inch of rain water be stored for reuse or infiltrated. The goal of this ordinance is to reduce the amount of pollutants from entering into the city s storm drain system by reducing the runoff from project sites. New projects are required to either provide for infiltration or reuse of stormwater, or pay a one-time fee based on the rain water volume. For this site the fee is approximately $790,000. In the Geotechnical Report, prepared by Diaz Yourman and Associates, dated December 13, 2011, the infiltration rate on the site is negligible. Existing site soils are clayey soils with low permeability therefore infiltration is not feasible. Therefore infiltration options have not been considered. Due to the limited ability to infiltrate, a rainwater harvesting system has been investigated. Rainwater harvesting involves collection systems for rainwater from rooftops and other site surfaces. The harvested rainwater provides an alternative source of water. This water can include contaminants such as windblown dust, avian fecal matter, fertilizers, oil and grease. Harvested rainwater may require filtration and disinfection when needed. The water is stored in a cistern and then pumped to its use. In order to develop this option, the design information was needed to proceed. The design team first needed to answer the following questions: How much water can be captured during an average rainfall year? What are the current regulations for rainwater harvesting? How can this water be used, or what are its uses? TANK SIZE How much water can be captured during an average rainfall year? An analysis was performed to determine the amount of rainfall that can be captured on an average annual basis. A number of agencies have collected rainfall data over the last 50 years. This data shows an average annual rainfall of 12.5 inches of rain for the project site. The Exposition Metro Line Construction Authority 5 W2 Design, Inc.

7 Expo Rail Operations and Maintenance Facility total site area is 9.34 acres. The standard in cistern design is to use a 30% reduction for infiltration, evaporation, and runoff in available rain for storage. The total possible rain available for capture on an average annual basis is 2.2 million gallons. This rain comes in periodic events throughout the year. During the wet months, October to May, two to three measurable rain events (greater than.75 inch) occur per month. The issues involved include meeting the demands, satisfying the URMP and SUSMP regulations, as well as maximizing the capture of rain to meet the project goal of having zero net discharge (average annual basis). The size of the tank necessary to satisfy the regulatory mitigated volume is 104,000 gallons. The volume necessary to have zero net discharge (average annual basis) is 800,000 gallons. The 800,000 gallon tank will also store enough water throughout the rainy season (October April) and through the summer months with a complete drawdown of the tank occurring in September (for average annual rainfall). REGULATIONS What are the current regulations for rainwater harvesting? The regulatory environment for rainwater harvesting is currently in flux. The California Plumbing Code, California Department Public Health and Los Angeles County Department of Public Health are the regulatory agencies that have jurisdiction over rainwater harvesting and its uses. Currently, there are no provisions within the California Plumbing Code for rainwater harvesting. Los Angeles County Public Health has recently put together a matrix to determine what requirements and permitting must be met for different uses (Appendix A). USES How can this water be used, or what are its uses? Various uses for this water have been identified. Some uses were deemed infeasible and eliminated due to the water quality requirement imposed by the California Plumbing Code and the Los Angeles County Department of Public Health standards. The uses excluded were toilet flushing and other domestic water uses. The uses identified as feasible for additional investigation are train wash, truck wash, blow down, and irrigation. The demands for these uses have been compiled and the results are included with this report. These uses are shown at their relative locations on the site plan exhibit below (See Figure 1). Exposition Metro Line Construction Authority 6 W2 Design, Inc.

8 Expo Rail Operations and Maintenance Facility TRAIN WASH DOMESTIC WATER MAKEUP NON-POTABLE CISTERN WATER BLOW DOWN CISTERN P TRUCK WASH BLOW DOWN TRAIN WASH TRUCK WASH LANDSCAPE AREAS FIGURE 1 - NON-POTABLE CISTERN USES SITE PLAN Exposition Metro Line Construction Authority 7 W2 Design, Inc.

9 TANK LOCATION Expo Rail Operations and Maintenance Facility In the 30% level of completion plans, the team designed a tank that would be placed within the main building. The team was seeking some savings by combining walls for the pits and foundation walls with the tank. The advantage of doing so was that it could be placed in a central location on the site. The central location reduced storm drain runs to the tank and pumping runs to the uses. It also kept the tank from being under track work. The challenges were that the tank would need to be deeper than the pits, which caused the foundations to become deeper than necessary, therefore increasing the costs of foundations. Another alternative was to place the tank underneath the tracks in the train storage area. The tank options available were Steel Reinforced Pipe or Precast concrete which are designed with appropriate cover to accept H-20 highway truck loading that exceeds the LRT loading. This would centralize the tank, but maintaining or replacing elements could prove problematic for the operations the train yard. The possibility of having to remove sections of the track to repair a broken tank liner or leaking pipe, taking a section of rail out of service, is not desirable. For these reasons, a tank location outside of the storage tracks and the Main Building envelope was investigated. This led the team to investigate and analyze the east and west parking areas. The east and west parking areas presented challenges since they are not central to the site. Because of this challenge, having two separate systems was studied. Two separate tanks connected by a storm drain pipe running across the site were also investigated. Both of these options proved to have too many drawbacks to be developed any further. Instead, a tank located in the east parking lot was considered. This option proved feasible. Though it was not central to the site, this location had the advantage of being near the outfall. A 33-inch existing storm drain is located 20 feet east of the easterly property line, yet it has an existing tie-in via a 24 pipe from the existing Verizon site. Therefore, locating the tank underneath the easterly parking lot became the preferred option. Figure 2 shows the locations considered. Table 1 provides a bullet point comparison of the advantages and disadvantages of each location. Exposition Metro Line Construction Authority 8 W2 Design, Inc.

10 Expo Rail Operations and Maintenance Facility UNDER MAIN BUILDING (30% DESIGN) UNDER STORAGE TRACK UNDER EAST PARKING LOT (60% & 100% DESIGN) FIGURE 2 - CISTERN LOCATION EXHIBIT Exposition Metro Line Construction Authority 9 W2 Design, Inc.

11 Expo Rail Operations and Maintenance Facility Location Advantage Disadvantage Under Rail Yard Storage Tracks Central location o shortens pump runs o allows tanks to be shallow o shortens runs of stormwater conveyance pipe Pre-cast concrete, and SRPE pipe options available Replacement would shut down portion of rail yard Utilities will need to be routed around tank Manhole access would be in the rail yard Limited access to cistern for maintenance Under Main Building This location was included in 30% design Central location o shortens pump runs o allows tanks to be shallow o shortens runs of stormwater conveyance pipe Pre-cast option may be available No conflict with site utilities Under East Parking Lot This location was included in the 60% design. Shortest outfall distance Limited conflict with site utilities Precast, and Pipe options available Traffic loading requirement reduced Accessible for maintenance Roof drains will require separate preliminary treatment High cost as noted in 30% cost estimate Incorporation with footing caused and increase in depth of footing further increasing costs Longer pump runs Longer storm drain conduit runs Tank will have to be deeper to accommodate longer storm drain runs from east side of site TABLE 1 - CISTERN LOCATION COMPARISON Exposition Metro Line Construction Authority 10 W2 Design, Inc.

12 CISTERN OPTIONS Expo Rail Operations and Maintenance Facility The possible tank materials for cisterns include buried pipe, below ground or above ground plastic or metal tank, or cast-in-place or pre-cast concrete vaults (Figure 3 shows 3 options considered). In order to select possible materials for the tank it was essential to understand the project, site and use parameters. The possible materials for the site excluded corrugated metal pipe or tank because of the possible stray current and native acidic soils. The prefabricated tanks both above and below ground options are feasible because the size of these tanks does not meet the size needed and sighting an above ground tank is not possible. For the 100,000 gallon plus tank size that the project requires to meet the regulatory storage for SUSMP and the City of Santa Monica, two possible materials were identified. These are Steel Reinforced Polyethylene Pipe (SRPE) and Pre-Cast Concrete tank units. The SRPE pipe is a water tight pipe solution and the steel reinforcing provides the strength equivalent of a reinforced concrete pipe (RCP). The pre-cast concrete tank units are constructed in a building block pattern, setting them side-by-side or stacked on top of one another. The pre-cast option provides the tightest footprint or the greatest volume per square foot of area. Old Castle StormCapture CONTECH StormTrap CONTECH Steel Reinforced High Density Polyethylene FIGURE 3 - CISTERN TYPES Exposition Metro Line Construction Authority 11 W2 Design, Inc.

13 Category Design life (Warranty) Oldcastle StormCapture Precast Concrete Tanks 50 year warranty Polypropylene liner (25 year by liner manufacturer backed by 25 additional years by Old Castle) Construction Small Crane Modular design Native Backfill Wrapped with Liner Precast Expo Rail Operations and Maintenance Facility Contech StormTrap Precast Concrete Tanks 25 year design life of Polypropylene liner Small Crane Modular Design Native Backfill Wrapped with Liner Pipe Contech Steel Reinforced Polyethylene Pipe Cistern years Back hoe Joints are fused for water tight connection Light weight compared to RCP Loading HS-20 loading HS-20 loading HS-20 loading Layout Footprint is compact due to rectangular box storage TABLE 2 - CISTERN TYPE COMPARISON Footprint is compact due to rectangular box storage Pipe footprint is much larger than the precast concrete tank option Exposition Metro Line Construction Authority 12 W2 Design, Inc.

14 Expo Rail Operations and Maintenance Facility SECTION 2: BASIS OF ANALYSIS METHODOLOGY Typically rain water harvesting systems are analyzed based upon a monthly rain demand chart. Tanks are sized based upon this analysis. This methodology is overly simplistic and results in a tank size that is overly conservative. The demand or drawdown does not occur at one point during the month. Furthermore, rainfall does not occur at that same point in the month. Instead, drawdown will occur throughout each day. Rain events happen at random throughout the month. For instance, for the Expo OMF project, in order to have a zero runoff system that supplied water for all uses using the monthly rainfall/monthly demand model, a 1.2 million gallon tank would be necessary. Conversely, with the daily drawdown/random rainfall model, the result would be a tank size of 800,000 gallons. Therefore, the model used in this analysis was a daily drawdown with random rainfall model. Measurable rain events occur 2-3 times per month during the rainy months and once per month during non-rainy months for the City of Santa Monica (See Appendix B). With this data, the demand for the various uses was totaled and used to provide the drawdown demand for the cistern. Rain events were placed at random through each month. It was found that moving the dates of rain events did not alter the findings significantly. With this analysis, the design team was able to graphically predict the tank level or volume throughout the year. The graphs of the results are shown in the following pages. RAIN DATA See Appendix B Rain Data was prepared by the Natural Resources Conservation Service National Water and Climate Center, Portland, Oregon. Exposition Metro Line Construction Authority 13 W2 Design, Inc.

15 Expo Rail Operations and Maintenance Facility WATER DEMAND BY USE TABLE 3 - IRRIGATION DEMAND Landscape Irrigation Month Gallons Gallons Per Day Jan 8, Feb 10, Mar 15, Apr 20, May 24, Jun 26, Jul 27, Aug 25, Sep 20, Oct 15, Nov 11, Dec 8, TOTAL 213,960 7, Source: Sweeney & Associates, April 12, 2012 TABLE 4 - INDUSTRIAL WATER DEMANDS Industrial Water Industrial Water Use Gallons Per Gallons Per Day Month Blow Down 68,400 2,280 Truck wash 68,400 2,280 Wash Building Potable Water Demand 73,650 2,455 Wash Building Stormwater Demand 14, TOTAL 225,030 7,501 Source: Maintenance Design Group Exposition Metro Line Construction Authority 14 W2 Design, Inc.

16 Expo Rail Operations and Maintenance Facility SECTION 3: COST ANALYSIS SANTA MONICA WATER COSTS The current price for water is $3.16 per hundred cubic feet of water (748 gallons). The price jumps to $7.77 when the allotted threshold is exceeded. 5,280 hundred cubic feet of water is the threshold for an 8 meter per month. LIFE-CYCLE COST ANALYSIS The projected life cycle for the project is 50 years. A life-cycle cost analysis summary table is shown below. The build option includes costs of the Steel Reinforced Polyethylene Pipe cistern with its appurtenances was used because its costs were median value between the other tank options. Annual costs for the build option such as maintenance, and power costs to run the pumps was brought back to present value using a life cycle of 50 years and 4 percent inflation. Pump replacement was estimated for 10 years. The pump replacement was also brought back to a present value. These values were added to the cost of purchasing and installing the system. The total present value of the system is shown below. Other tank options can be compared by replacing the tank purchase and installation of SRPE with a precast concrete tank. The no-build option includes costs for water and sewer fees annually given 4 percent inflation. These costs were added to the Urban Runoff Mitigation Fee and the total is shown below. The No-build option cost exceeds the build option for the rain water harvesting system by $250,000 when brought to a present value. Annual inflation may not average 4 percent over the 50 year design life. Yet, there is uncertainty where water and sewer costs may go in the future. It is reasonable to assume 4 percent for annual inflation for water costs. This number could increase dramatically when considering the historic water rights battles to supply water to Southern California and population growth in the region (See Hedging Future Water Costs on page 25). TABLE 5 - LIFE-CYCLE COST ANALYSIS Life-Cycle Assumptions Quantity Units Water Use for Irrigation, Blow Down, and Truck Wash per 1,878,360 Gallons year Annual Inflation 4% Life Cycle 50 years Current Cost of Water* $3.16 HCF Current Sewer Costs $4.83 HCF Sewer Discharge Factor 89% Gallons per Cubic Feet 749 Gal/CF Exposition Metro Line Construction Authority 15 W2 Design, Inc.

17 *water costs jump to $7.77 when allotted tier limit is exceeded Build Option Expo Rail Operations and Maintenance Facility Cost Tank purchase and Installation $788,000 Annual Maintenance Cost $3,500 Annual Replacement Costs (Pumps, etc.) $833 Annual Pump Power Costs** $2,708 Total Present Value Cost of Reuse System $939,262 ** Pump: 45 GPM, 5 HP, 230 V, 23 A, 5.29 kw, 2 Pumps - $5,000 each, 10-yr. life. Power costs for SCE - $ 0.14 / kwh, assuming 10 hours of use/day No-Build Option Cost Cost of water (Annual) $7,925 Cost of sewer (Annual) $10,780 URMP Fee $787,497 Total Present Value Cost of URMP Fee + Water $1,189,323 Exposition Metro Line Construction Authority 16 W2 Design, Inc.

18 SECTION 4: OPTIONS CONSIDERED Expo Rail Operations and Maintenance Facility In order to provide EXPO with the most effective and efficient solution, a study was performed to investigate how much water the system could provide on a daily basis, given different tank sizes. The tank sizes investigated were 800,000 gallons and 104,000 gallons. The 104,000 gallons represents the City of Santa Monica URMP regulatory volume. In analysis of this system the tank volume was calculated with the three possible capture areas. The main site, which is the area bounded by 7 feet south of the southerly mainline track to the north and southerly by the proposed property adjacent to the buffer area, to the west by the Stewart Street right of way and to the east by the property line adjacent to the IMAX site. See Figure 4. FIGURE 4 - SITE AREAS Site Areas (Shown in Figure 4): Exposition Metro Line Construction Authority 17 W2 Design, Inc.

19 Storm Water Storage Volume - CF 1-Jan 12-Jan 23-Jan 3-Feb 14-Feb 25-Feb 7-Mar 18-Mar 29-Mar 9-Apr 20-Apr 1-May 12-May 23-May 3-Jun 14-Jun 25-Jun 6-Jul 17-Jul 28-Jul 8-Aug 19-Aug 30-Aug 10-Sep 21-Sep 2-Oct 13-Oct 24-Oct 4-Nov 15-Nov 26-Nov 7-Dec 18-Dec 29-Dec Expo Rail Operations and Maintenance Facility Main Site is 8.34 Acres Main Site plus Centinela Access Drive is 9.7 Acres Main Site plus Centinela Access Drive and Mainline Drainage Area is Acres 800,000 GALLON (107,000 CF) TANK The 800,000 gallon tank size was selected for analysis because it represented a volume near the maximum possible capture volume for average annual rainfall. The 800,000 gallon tank was analyzed for three scenarios. The first is to provide water for all possible uses (Train Wash, Truck Wash, Blow Down, and Irrigation). The second is to provide water for all uses minus the train wash. The train wash has additional requirements for water clarity than the other uses (5 micron maximum particulate size which is domestic water quality). Additionally the train wash is the largest water user on the site and has its own water reclamation system. The third option is to supply water only for irrigation. The analysis showed that supplying all uses would draw down the 800,000 gallon tank during the second week of July. The tank would be dry and system then would need to have City water make up for the rest of the summer months until the first measurable rain event(approximately 4 months) EXPO OMF - Daily Cistern Volume (800,000 Gal Tank)- Based Upon Avg Annual Rainfall - All Uses 0 Daily Data Main Site, Drive, & ML Main Site w/ Drive Tank Volume (Main) FIGURE 5 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - ALL USES An 800,000 gallon cistern would capture and hold nearly all of the water needed to supply the Truck Wash, Blow Down, and Irrigation Water for the entire year. The tank Exposition Metro Line Construction Authority 18 W2 Design, Inc.

20 1-Jan 12-Jan 23-Jan 3-Feb 14-Feb 25-Feb 7-Mar 18-Mar 29-Mar 9-Apr 20-Apr 1-May 12-May 23-May 3-Jun 14-Jun 25-Jun 6-Jul 17-Jul 28-Jul 8-Aug 19-Aug 30-Aug 10-Sep 21-Sep 2-Oct 13-Oct 24-Oct 4-Nov 15-Nov 26-Nov 7-Dec 18-Dec 29-Dec Storm Water Storage Volume - CF Expo Rail Operations and Maintenance Facility would empty the second week of October (which is the beginning of the rainy season). It also provides a zero runoff solution for the average annual rainfall. The 800,000 gallon tank would completely capture the 2-year design storm. Comparatively, the 800,000 gallon tank is less than the 10-year storm event volume of 1.02 million gallons, and greater than the 2-year storm volume of 538,000 gallons EXPO OMF - Daily Cistern Volume (800,000 Gal Tank)- Based Upon Avg Annual Rainfall - No Wash Bldg Daily Data Main Site, Drive, & ML Main Site w/ Drive Tank Volume (Main) FIGURE 6 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - NO WASH BUILDING Exposition Metro Line Construction Authority 19 W2 Design, Inc.

21 1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 1-Mar 11-Mar 21-Mar 31-Mar 10-Apr 20-Apr 30-Apr 10-May 20-May 30-May 9-Jun 19-Jun 29-Jun 9-Jul 19-Jul 29-Jul 8-Aug 18-Aug 28-Aug 7-Sep 17-Sep 27-Sep 7-Oct 17-Oct 27-Oct 6-Nov 16-Nov 26-Nov 6-Dec 16-Dec 26-Dec Storm Water Storage Volume - CF Expo Rail Operations and Maintenance Facility The 800,000 gallon tank would be too large to supply only the Irrigation demand. The tank actually would never draw down after initially being filled. Figure 7 shows this condition EXPO OMF - Daily Cistern Volume (800,000 Gal Tank)- Based Upon Avg Annual Rainfall - Irrigation Only Daily Data Main Site, Drive, & ML Main Site w/ Drive Tank Volume (Main) FIGURE 7 - DAILY CISTERN VOLUME (800,000 GALLON TANK) - IRRIGATION ONLY Exposition Metro Line Construction Authority 20 W2 Design, Inc.

22 1-Jan 11-Jan 21-Jan 31-Jan 10-Feb 20-Feb 1-Mar 11-Mar 21-Mar 31-Mar 10-Apr 20-Apr 30-Apr 10-May 20-May 30-May 9-Jun 19-Jun 29-Jun 9-Jul 19-Jul 29-Jul 8-Aug 18-Aug 28-Aug 7-Sep 17-Sep 27-Sep 7-Oct 17-Oct 27-Oct 6-Nov 16-Nov 26-Nov 6-Dec 16-Dec 26-Dec Storm Water Storage Volume - CF 104,000 GALLON (14,000 CF) TANK Expo Rail Operations and Maintenance Facility The 104,000 gallon option provides enough water for irrigation yet with the demands as designed the tank would remain full throughout the year (not drawing down). Nevertheless, if the irrigation demands are increased by 50%, the system works efficiently and draws down completely at the beginning of the following rainy season. See Figure 8 below EXPO OMF - Daily Cistern Volume (104,000 Gal Tank - URMP Volume)- Based Upon Avg Annual Rainfall - Irrigation Only- 50% Increase in Irrigation Demand Daily Data Tank Volume (Main) FIGURE 8 - DAILY CISTERN VOLUME (104,000 GALLON TANK) - 50% INCREASE IN IRRIGATION DEMAND Exposition Metro Line Construction Authority 21 W2 Design, Inc.

23 INCREASE SITE PERVIOUS AREAS Expo Rail Operations and Maintenance Facility One solution not investigated is to increase the site s impervious areas. Currently, the site s impervious areas are the ballasted areas, landscape areas, and the pervious paver parking areas. Adding green areas is difficult to impossible given the limited site area. Green roofs do not appear to be a possibility. This leaves changing out impervious pavement areas currently shown as asphalt and concrete for permeable pavement. Although the manufacturers of these products claim to be able to have truck loading on permeable pavers, this option will need to be thoroughly considered. PAY URMP FEE The City of Santa Monica Municipal Code Section includes urban runoff reduction requirements for all applications for new development and redevelopment within the City. Project applicants are required to develop an urban runoff mitigation plan that provides for the infiltration or treatment of projected runoff for the new development by an amount equal to or greater than the volume of runoff produced from a storm event (Section (b)). The ordinance defines a storm event as 0.75 inches of rainfall within a consecutive 24-hour period. Projects that exhibit difficulty in infiltrating or reuse may pay an Urban Runoff Reduction Fee (In Lieu Fee, Section (q)). The following equations are provided by the City to calculate the URMP Planned Mitigation Volume and In Lieu Fee. Required Storage for Reuse/Infiltration In Lieu Fee Calculation Exposition Metro Line Construction Authority 22 W2 Design, Inc.

24 Expo Rail Operations and Maintenance Facility SECTION 5: DESCRIPTION OF THE EXPO OMF SYSTEM FIGURE 9 - RAINWATER HARVESTING SYSTEM Exposition Metro Line Construction Authority 23 W2 Design, Inc.

25 SYSTEM Expo Rail Operations and Maintenance Facility Rainwater that lands on the site is captured by the catch basins (with filter inserts) in paved areas, roof down drains on buildings and under drain system in the ballasted rail yard. Water is conveyed by storm drain conduits to the water quality unit (hydrodynamic separator) for pre-treatment to remove trash, sediment and oil. Water is then stored in 800,000 gallon cistern. Water from the cistern is then pumped to industrial water uses and subsurface irrigation. In the event that there is no rainwater in the cistern, an automatic control valve will allow domestic water to fill the lines so that the uses can continue to function. Backflow preventers will prevent non-potable cistern water from contaminating the domestic water. Water that is used in the Wash Building will be recycled and reused for train washing. The water that is discarded from the Blow Down, Truck Wash, Deep Clean and Wash Building will be sent to a clarifier before being discharged into the public sewer system. MAINTENANCE The maintenance of the tanks, pumps and controls, although not substantial, will be more than turning on the faucet and using only domestic water. The hydrodynamic separator will need to be cleaned once a year prior to the rainy season. Tanks will need to be cleaned and maintained once every 5 years. Pumps and controls will need to be maintained and replaced as necessary. WATER QUALITY Disinfection is being included in the system to eliminate the possibility of Legionnaires Disease. This will include an ultraviolet light system after the pump from the cistern prior to the non-potable cistern water being used for high-pressure spraying in the Truck Wash and Blow Down Areas. The disinfection is being recommended by the Los Angeles County Department of Public Health (LACDPH) for worker protection. LACDPH will be conducting tests on the system during the first couple of years of service to verify that no cross-connections have been made with domestic water and to ensure that water is safe for spraying operations. Disinfection is not required for subsurface irrigation. Site irrigation will be drip lines and bubblers which are considered subsurface irrigation. Exposition Metro Line Construction Authority 24 W2 Design, Inc.

26 Expo Rail Operations and Maintenance Facility SECTION 6: BENEFITS TO RAINWATER HARVESTING SYSTEM BENEFITS Rain Water Harvesting LEED Points There are potentially 12 LEED points to be gained when implementing a rainwater harvesting system. Sustainable Sites Credit 6.1: Stormwater Design-Quantity Control Sustainable Sites Credit 6.2: Stormwater Design-Quality Control Water Efficiency Prerequisite and Credit 6.1: Water Use Reduction Water Efficiency Credit 1: Water Efficient Landscaping Water Efficiency Credit 2: Innovative Wastewater Technologies Innovation in Design Credit 1: Innovation in Design Each of these credits is discussed in Appendix C. Hedging Future Water Costs Southern California, a semi-arid region, imports more than 60% of the water used. The sources for water include the Colorado River, the San Francisco Bay-Delta, and the Owens River Valley. Recent regulations have limited water supplies from Bay-Delta and Owens River. Additionally, there has been a constant battle over Colorado River water rights. There are three states that lay claim to the Colorado Rivers Lower Basin; Arizona, Nevada, and California. Each has growing population areas such as Los Angeles, Phoenix, Tuscan, and Las Vegas. Water is being transferred from irrigation of farmland to satisfy the growing populations of these arid cities. The future of water resources available to Southern California is unknown as is the cost of water. In light of the current battles for water, the future could include substantial conservation efforts and substantial increases in water cost. Therefore, efforts such as rainwater harvesting can help hedge future water costs. SECTION 7: CONCLUSION The 800,000 gallon tank meets the project goal of zero discharge and exceeds local regulations. It also provides water throughout the year for three different uses on the site. Additionally, it is less costly than the no-build option to pay the URMP and buy water. Therefore, the 800,000 gallon tank is being proposed for the project. Exposition Metro Line Construction Authority 25 W2 Design, Inc.

27 Expo Rail Operations and Maintenance Facility APPENDIX A LA COUNTY DEPARTMENT OF PUBLIC HEALTH RAINWATER HARVESTING MATRIX Exposition Metro Line Construction Authority 26 W2 Design, Inc.

28 APPENDIX B RAIN DATA Expo Rail Operations and Maintenance Facility Rain Data Prepared by the Natural Resources Conservation Service National Water and Climate Center, Portland, Oregon. TABLE 1.--TEMPERATURE AND PRECIPITATION (Recorded in the period at : SANTA MONICA PIER, CA7953) Temperature Precipitation _ 2 years in 2 years in 10 Month 10 will have-- Average will have-- Average Average Average Average Average Maximum Minimum number of Average number of snowfall daily daily temperature temperature growing Less More days with maximum minimum higher lower degree than-- than inch than-- than-- days* or more 0F 0F 0F 0F 0F Units In In In In January February March April May June July August September October November December Exposition Metro Line Construction Authority 27 W2 Design, Inc.

29 Expo Rail Operations and Maintenance Facility Yearly: Average Extreme Total * A growing degree day is a unit of heat available for plant growth. It can be calculated by adding the maximum and minumum daily temperatures, dividing the sum by 2, and subtracting the temperature below which growth is minimal for the principal crops in the area (50 degrees. F) Exposition Metro Line Construction Authority 28 W2 Design, Inc.

30 APPENDIX C RAINWATER HARVESTING LEED CREDITS ARTICLE Expo Rail Operations and Maintenance Facility Exposition Metro Line Construction Authority 29 W2 Design, Inc.