TECHNICAL MEMORANDUM. Nathan D. Maier Consulting Engineers

Transcription

1 TECHNICAL MEMORANDUM To: John Hoppie, DART From: URS Corporation Peng Zhao, PE Chad Allen, PE Lakhbir Chauhan, PE Herb Miller, PE Nancy Stavish Nathan D. Maier Consulting Engineers Bill Wallace, PE Heidi Fischer, PE Date: February 6, 2012 RE: Cotton Belt Draft Pump Station Study for Deep Trench Concept in North Dallas General Planning Consultant Services - Dallas Area Rapid Transit (DART) Contract ID C Task Order #4: Cotton Belt PE/EIS URS Project Number: Introduction During the development of the DART 2030 Transit System Plan, the Dallas City Council passed a resolution with their recommendations for the plan. This included conditions specific to the Cotton Belt Corridor project, one of which was that the rail line be below grade from at least 1,500 feet east of Meandering Way to 2,000 feet west of Preston Road. In their resolution adopting the 2030 Transit System Plan in October 2006, the DART Board of Directors included a set of Corridor Development Conditions to guide planning efforts in the corridor, including an acknowledgement of the City s preference for a trench. As such, DART is examining a range of options to place the rail line below grade as part of the Preliminary Engineering (PE) effort. The purpose of this memorandum is to develop and analyze a concept for a deep trench option. The deep trench concept would depress the rail alignment at least 15 feet below grade. The handling of storm water drainage at creek crossings is the most critical challenge for this option. There are three creek crossings between Hillcrest on the east and Preston on the west: Osage Branch Crossing 1, located just east of Davenport Court; Osage Branch Crossing 2, located just south of Duffield Drive; and, McKamy Branch Crossing, approximately 300 feet north of Davenport Drive. 1

2 Implementation of a deep trench option would require that water in all three creeks be pumped past the trench. Photographs of existing conditions can be found in Appendix A. A shallow trench option has also been developed that avoids the need for pumps. The following sections outline the drainage concept for this deep trench option, including options for pumping stations, types of pumps, and use of submersible electric motors. This is followed by an analysis for each creek crossing, including design considerations, power needs, probable annual operating costs, and a summary of estimated capital costs. 2.0 Drainage Concept The primary objective of the drainage concept for the deep trench option is that the 100-year floodplain water surface elevations must be conserved in order to avoid adding new inundation areas or structures to the existing flood plain. Storm water velocities within the creek must also be controlled to avoid erosion and compromising the integrity of the creek banks. The drainage concept consists of capturing the water upstream of the alignment and pumping it under the tracks, over to the downstream side of the tracks. The following is a preliminary analysis of the transfer pumping under the tracks, as well as suggestions for the most economical transfer pumping systems suitable for the application. Several options are available for the pump station design: 1. Vertical line shaft axial flow, low head, high specific speed pumps with gear drives and electric motors as the prime movers. 2. Horizontal line shaft axial flow, low head, high specific speed pumps with gear drives and electric motors as the prime movers. 3. Vertical low head, high specific speed, line shaft axial pumps with submersible electric motors directly coupled and operating under water. 4. Horizontal line shaft axial flow, low head and high specific speed pumps with close coupled submersible electric motors as the drivers. 5. Horizontal line shaft axial flow, low head, high specific speed, axial flow pumps with hydraulic drives. The selection of the type of pump configuration impacts the layout and expense of the station. Vertical line shaft configurations require stations with elevated decks, specific design approach channels and load bearing decks and walls. The pump stations are designed based on Hydraulic Institute Standard recommendations and further verified with physical and numerical modeling. The decks support the gears and the drivers, with either diesel engines or electric motors being the most common. Another unique option available is the inline pumps, which eliminate the need for the conventional station altogether. However there are limits to the power input. These are very suitable for low head (water surface elevation differences between upstream and downstream side of the railroad tracks), high volume applications (4,550 CFs and 14,900 CFS), as in this case. 2

3 Using the electric motor eliminates the noise factor associated with the diesel equipment and is most suited to residential applications and for low head, large volume stations. Option 4 above is therefore the most economical choice, eliminating the need for a conventional station and using submersible electric motors, and meets the low-noise requirements of a residential neighborhood. The number of pumps and pump sizes described in this report at each of the creek crossings are approximated for the conveyance of the peak flow rate associated with the 100-year design storm event. During smaller storms and when the creek flow is less than the design peak flow, the number of pumps required to be operational will be less than the overall number of pumps provided at each of the crossings. The simultaneous operation of all pumps at a specific creek crossing will only rarely be required. 2.1 Types of Pumps The pumps most suited to the low head applications with large volumes of flow are high specific speed pumps. The specific speed is a type number and identifies the range of operation of different design pumps. Centrifugal pumps are low specific speed; the mixed flow pumps lie in the medium specific speed range; the axial flow pumps lie on the extreme high end range of the specific speed. The specific speed is defined as follows: Ns= Pump operating speed RPM Q= Rate of design flow in GPM H= Design Head in FT A large volume of flow and low heads would yield a high specific speed number. For axial flow pumps, the general range for the specific speed is 10,000 to 15,000 RPM. This application calls for a transfer of very large volumes against minimal heads caused by the water elevation difference between the suction and discharge sides of the system and losses through the transfer piping system. Because of the limits on the size of the pumps, several pumps of axial flow design would be required to handle the desired flow transfers. Electric motor drives would be used to minimize the noise impact on the neighborhood. The pumps used would be horizontal inline submersible electric pumps as shown on the exhibits in Appendix B. The design meets the unique requirement of the application and is ideally suited for inline application eliminating the need for a formal pump station, saving space and providing economic advantage in the process. 2.2 Submersible Electric Motors 3

4 The motors are designed for under water applications. The motors can effectively operate in a horizontal layout when adequately supported. The motors become a part of the pump bowl design and the water flows around the motor providing very effective cooling. The motors are directly coupled to the propeller through short shafts designed with seals to prevent leakage into the motor windings. Adequate alarms are provided to detect the presence of moisture in the motor windings. These motors also have bearings designed to take the thrust loads imposed by the propeller. 3.0 Osage Branch Creek Crossings 1 and 2 The following sections present the analysis for Osage 1 and 2 crossings. The total transfer rate is based on 4,550 CFS at each crossing with a minimal static lift. The head on the pump will include the losses though the piping and elbows and the dynamic losses. These total system losses are unknown at the moment and, therefore, are estimated. 3.1 General Analysis Submersible electric pumps installed in horizontal pipes of 96-inch to 120-inch diameter are proposed. These pumps can be installed in line with the pipeline, saving on the footprint of a pump station, as well as simplifying the installation and removal of the equipment without the use of very large cranes. A typical submersible electric pump cross-section is shown in Figure 1. The pumps become a part of the transfer pipe line. The pump consists of an axial flow pump suction, propeller, bowl and the submersible electric motor mounted to the bowl with appropriate supports and seals. The water flows over the motor providing all the cooling needed for the motor. Typical flow velocities around the motor are eight to 12 feet per second. Bearings in the motor take the thrust and provide alignment of the pump and motor shaft. Depending on the size of the motor available, theses pumps provide an ideal solution for low head applications, without the need for a formal pumping station. The pumps are non-intrusive and can be functional underground in the residential neighborhoods. Noise mitigation is provided by the use of electric power. Figure 1. Section of a typical Horizontal Submersible Electric Pump 4

5 The advantages of this type of arrangement are numerous and listed below: 1. Least installation costs 2. Ease of pump access 3. Ease of use 4. Low maintenance 5. The need for a pump support structure and approach channels are eliminated 6. The pump house can be designed to allow for the pumping unit to stay dry and offer access for maintenance. The power source can be assured. In residential situations, power supply from two independent grids allows for assurance of needed power supply during inclement weather. Capital costs for diesel generator back-up power at each pump station have also been included in the cost estimates as part of this report (see Section 5.0). The pumps will typically be operated with electric power made available by the local utility. A pump house for the starters and control equipment built above the flood zone would provide suitable housing for the controls. Suitable noise attenuation will be provided to minimize the sound levels. 3.2 Design Considerations for Each Station Design considerations for each pump station are summarized below. Total flow = 4,550 CFS = 2,042,040 GPM Proposed number of pumps = 7 Proposed Pump size = 96-inch Rate of flow for each pump = 291,720 GPM Proposed transfer pipe size = 96-inch to 120-inch No of pipes = 7 Expected velocity through each pipe = 8-12 feet/sec Expected head on the pump = 5 feet Expected min efficiency for the pump = 80% Expected motor horsepower for each pump = 500 HP = 375 KW Total power required = 3 MW for one station Total power required = 6 MW for two stations Exhibits 1 and 2 in Appendix B detail the concept. The pumps will be mounted in the pipe on the suction side of the tracks for ease of access, removal and reinstallation of pump units. Control valves shall be provided as needed to isolate the pumps in the piping systems. The estimated size of the building to house the control equipment is 40 feet long by 30 feet wide by 20 feet high. The estimated cost of equipment including the motors, controls and 5

6 pumps is $8-12 million. The estimated cost of making the power available at the site would be $1-2 million. This estimate does not include the building costs. It is possible to use fewer pumps of larger size, if available, to possibly reduce the costs. 3.3 Rough Estimate on Power to Sites Expected motor horsepower for each pump = 500 HP = 375 KW Total power required = 3 MW/ per station Total power required for two stations= 6 MW 3.4 Estimated Operating Costs per Year The following operating costs are based on a daily basis, meaning that the pumps run for 24 hours a day. The costs for monthly/annual expenses can be computed by estimating the number of expected operating days in a year. The power consumption per hour of operation for each station = 3 MW Estimated cost per MW = $70/MW Hour Daily operating costs = $5,040/ per station Daily operating costs for two stations = $10,800 per day Assuming operation for 50 days a year, the annual costs to operate two stations would be estimated at $540,000 Estimated annual maintenance costs for two stations are $800,000 Total estimated annual operating costs for Osage Crossings 1 and 2 = $1,340,000 It should be noted that this is considered a conservative estimate of the yearly operating requirements related to power consumption because, as described earlier, all pumps at each crossing will not typically be required to be operating simultaneously. Instead, less than the total number of pumps will be operating during many of the 50 days of the year mentioned above. At the same time, it is known that local electricity providers may require the owner to pay a year-round demand surcharge which compensates the provider for the act of making the peak power demand available at all times. The amount of this anticipated demand surcharge is currently unknown, so the above information has been used in this report for the purposes of calculating the operating cost estimate. Layouts, plan and elevation views for the Osage Branch crossings can be found in Appendix B Exhibits 1 and McKamy Branch Creek Crossing This section documents the analysis of the McKamy Branch Creek crossing. The total flow transfer is based on 14,900 CFS with a minimal static lift. The head on each pump will include 6

7 the losses though the piping and elbows and the dynamic losses. The total losses are unknown at the moment and, therefore, are estimated. 4.1 General Analysis Submersible electric pumps installed in horizontal pipes of 144-inch diameter are proposed. The advantages of this arrangement are numerous: 1. Least installation costs 2. Ease of pump access 3. Ease of use 4. Low maintenance 5. Assured power supply from two substations allows for dependable operation 6. The need for a pump support structure and approach channels are eliminated 7. The pump house can be designed to allow for the pumping unit to stay dry and available access for maintenance. The pumps will typically be operated with electric power to be made available by the local utility. A pump house for the starters and control equipment built above the flood zone would provide suitable housing for the controls. Suitable noise attenuation shall be provided to minimize the sound levels. 4.2 Design Considerations Design considerations for this pump station are summarized below. Total flow = 14,900 CFS = 6,687,120 GPM Proposed number of pumps = 24 Proposed pump size = 96-inch Rate of flow for each pump = 278,630 GPM = 620 CFS Proposed transfer pipe size = 144-inch No of pipes = 24 Expected velocity through the pipe = 5.5 feet/sec Expected head on the pump = 4 feet Expected minimum efficiency for the pump = 80% Expected motor horsepower for the pump = 400 = 300 KW Total power demand = 7.5 MW Exhibit 3 in Appendix B details the concept for this crossing. The pumps will be mounted in the pipes on the suction side of the tracks for ease of access, removal and reinstallation of pump units. Control valves shall be installed to isolate the pumps for ease of removal. The estimated size of the building to house the generators and control equipment is 60 feet long by 30 feet wide by 20 feet high. The estimated cost of equipment including the motors, 7

8 controls and pumps is $28-34 million. This estimate does not include the building costs. Estimated cost to make the necessary power available would be approximately $3-4 million. 4.3 Rough Estimate on Power to Site Expected motor horsepower for each pump = 400 HP = 300 KW Total power required = 7.2MW 4.4 Estimated Operating Costs per Year The following operating costs are based on a daily basis, meaning that the pumps run for 24 hours a day. The costs for monthly/annual expenses can be computed by estimating the number of expected operating days in a year. The power consumption per hour of operation for the station = 7.5 MW Estimated cost per MW = $70/MW Hour Daily operating costs = $12,600 per day Assuming operation for 50 days a year, the annual costs to operate the station would be estimated at $630,000 Estimated annual maintenance costs are $800,000 Total estimated annual operating costs for McKamy = $1,430,000 Total estimated annual operating costs for all three stations = $2.77 million Again, it should be noted that this is considered a conservative estimate of the yearly operating requirements related to power consumption of this facility. The layout, plan and elevation view for McKamy Branch Crossing can be found in Appendix B Exhibit 3. The current layout shows pumps stacked vertically in two rows in order to contain the proposed pump improvements within the modified horizontal limits of the channel. Although this configuration is believed to be possible, it may not necessarily be the most optimum layout. The final layout might include pump placement more strategically spread out on the upstream side of the crossing or still stacked vertically but offset for easier access. The final pump size might also be increased to possibly remove the need for stacking of some or all of the pumps. All conceptual pump layouts and sizes provided in this memorandum should be verified for feasibility and optimized for operational purposes during final design by using both physical and computational fluid dynamic (CFD) modeling analysis. 5.0 Opinion of Probable Construction Cost The estimated cost of construction presented in this section is organized in the Federal Transportation Administration (FTA) standard cost categories as detailed in Appendix C. 8

9 Osage #1 - $47,367,000 Osage #2 - $49,907,000 McKamy - $124,681,000 Associated railroad trench drainage $7,981,000 Diesel generator back-up for pump stations $55,178,000 Right-of-way and easement requirements - $3,000,000 Total capital costs for three pump stations and facilities = $288.1 million. 6.0 Environmental Issues 6.1 Water Resources U.S. Army Corps of Engineers would have jurisdiction over creeks and wetlands and would need to provide regulatory approval. Implementation of the pumps would result in substantial alteration to the watercourse beds and banks and riparian areas. Floodplain impacts would result, and the potential for downstream and upstream adverse effects would need to be considered. Due to the magnitude of the floodplain alterations, the process with the U.S. Army Corps of Engineers can be lengthy and no approval is guaranteed. 6.2 Aquatic Species There is the potential for negative impacts to aquatic life. 6.3 Vegetation/Wildlife Several acres of land would be cleared for construction of the pump station facilities. Land clearing would include removal of trees and other vegetation resulting in loss of habitat for wildlife. 7.0 Neighborhood Issues 7.1 Acquisitions and Displacements Installation of pump station facilities would result in property acquisitions and potential displacement of residents. Pump Stations would require several acres of land for ancillary buildings and parking areas. 7.2 Parkland/Section 4(f) Implementation of the Osage Branch #2 Pump Station would result in a property impact to Preston Green Park, a City of Dallas neighborhood park that features open space, a playground and a basketball court. Since this park is publicly owned, a statute known as Section 4(f) would apply. The statute provides protection to certain types of land and resources, such as 9

10 public parkland. Unless the use of Section 4(f) property is determined to have a de minimis impact, FTA must determine that no feasible and prudent alternative exists before approving the use of such land. 7.3 Visual Implementation of the pump stations would have an effect on the existing visual environmental. In addition to pumps being placed in the waterway, ancillary buildings would be required to house electrical equipment and maintenance supplies. 7.4 Noise and Air Quality The pump stations would produce noise associated with pumping activities. Sources of noise would include operating pump motors, generators and the sound of falling water. The implementation of the pump station would have the potential to emit air pollutants. Emissions from the pump motors or generators could produce carbon dioxide (CO 2 ). 7.5 Traffic/Parking Vehicle traffic to and from the pump station would be limited to trips associated with pump station maintenance and inspections. Each pump station would require a driveway and parking area to provide access. 8.0 Liability Issues The pumps could fail to function as designed due potentially to lack of proper maintenance or power outages which typically occur during major storm events. Failure of the pumps stations could result in flooding of the upstream properties, as well as the Cotton Belt passenger rail line. Public safety and life protection could be undermined. 9.0 Summary The above is a very preliminary development and analysis of a concept to convey storm water from the upstream side to the downstream side of the Cotton Belt in a deep trench configuration. The capital costs as well as the operating and maintenance costs are substantial, but are required under this option. A summary of rough order of magnitude cost elements are as follows: Annual operating costs - $2,770,000 Estimated capital costs (three pump stations and facilities) - $288,100,000 These costs are exclusive of the costs to place the alignment in the trench; these costs are only for the pumping requirements. Given the additional costs (both capital and annual operating), 10

11 DART developed a shallow trench option that eliminates the need for pumping. The shallow trench focuses on maintaining the natural environment and drainage systems as much as possible. The deep trench would significantly alter the natural setting and could affect wildlife and wetland habitats. More detailed development and analysis would be required to further evaluate the concept, specifically: Hydraulic backwater analysis for the creeks Physical and CFD analysis of pump layout and operation Possible pumping redundancy requirements to mitigate breakdown or emergencies Wetlands delineation and other environmental impacts Impacts to adjacent properties Easement and Right-of-Way requirements Impacts to proposed trail Regulatory and permitting requirements The design team has been evaluating several alignment alternatives in the North Dallas area. This memo has been developed in order to explore the costs involved in a deep trench alternative. The deep trench alternative, which requires pumping, is significantly more costly, both for construction and maintenance, than a shallow trench option. Additionally, the environmental impacts to the area could be substantial, and the potential risks and liability could undermine public safety. It is our professional opinion that pursuing an alternative that requires the placement of pump stations in fully developed residential areas is not in the best interest of the public. 11

12 Appendix A Existing Creek Condition Photos

13 Osage Branch crossing #1 panoramic view looking east at downstream face of RR bridge

14 Osage Branch crossing #1 looking north at upstream face of RR bridge

15 Osage Branch crossing #2 looking at downstream face of RR crossing, panoramic view spanning from looking northeast to looking southwest (Wing wall at bottom of picture is actually straight, distortion due to panoramic view see aerial)

16 Osage Branch crossing #2 panoramic view looking southwest at the upstream face of the RR crossing

17 McKamy Branch - looking north at downstream face of RR bridge

18 McKamy Branch panoramic view looking southeast at upstream face of RR bridge

19 Appendix B Conceptual Pump Layout Exhibits

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23 Appendix C Rough Order of Magnitude Capital Cost Estimates for Three Pump Stations

24 DART - Cotton Belt Regional Rail North Dallas Trench Option Pump Stations Rough Order of Magnitude Cost Estimate Estimate prepared by URS Date of Estimate : 12/22/2011 Osage Branch Crossing #1 Pump Station UoM Quanity Unit Price Amount Comments Earthwork Channel CY 80,000 $ $ 800,000 Clearing and grubbing of channel and work sites Tree/Wetlands Mitigation SF 261,360 $ 3.00 $ 784,080 6 acres = 6 x sf = SF Headworks concrete w/ trash racks CY 175 $ $ 87,500 concrete cost - depends on # of pipes Outlet works concrete w/ trash racks CY 175 $ $ 87,500 concrete cost - depends on # of pipes " subm. Elec. Pump EA 7 $ 1,300, $ 9,100,000 7 each 96" sbm. Elec. Pumps incl. 1 generator per pump Structural excavation Pipe & Pump Str. CY 11,167 $ $ 256, '+56' long x 150' wide x depth 10' for pipe and pump house Concrete Pipe, Prestressed (PCCP), 150,PSI, 96" LF 1015 $ $ 959,175 96" Pipe Structural excavation Power & Control Rm CY 444 $ $ 10,222 80' long x 30' wide x depth 5' for Power & Control Rm Stone Gabion Retaining Walls SY 2,070 $ $ 322,920 Gabion Box Systems,Gabions, galvanized steel mesh mats or boxes, stone filled Pump house 146'x56' + foundation SF 8,176 $ $ 5,723,200 $200/sf building + $500/sf foundation Power & Control House 80'x30' + foundation SF 2,400 $ $ 1,680,000 $200/sf building + $500/sf foundation Siphon / Environmental Flow Conduits LS 1 $ 100, $ 100,000 Siphon and conduits for einvironmental / low flow purposes Bring Electrical Power to Station AL 1 $ 1,000, $ 1,000,000 Osage Branch Crossing #1 Pump Station - Sub Total $ 20,911, % Contractor General Conditions % 30% (Subtotal of Amounts) $ 6,273, =(0.30 x subtotal) = A DART Add-On Allowance Contingencies % 32% (Subtotal of Amounts) $ 8,699, =(0.32 x [A+subtotal])=B Allocated Contingency % 20% (Subtotal of Amounts) $ 7,176, =(0.20 x [A+B+subtotal])=C Unallocated Contingency % 10% (Subtotal of Amounts) $ 4,306, =(0.10 x [A+B+C+subtotal]) Osage Branch Crossing #1 Pump Station - Total $ 47,366,900 Osage Branch Crossing #2 Pump Station UoM Quanity Unit Price Amount Comments Earthwork Channel CY 50,000 $ $ 500,000 Clearing and grubbing of channel and work sites Tree/Wetlands Mitigation SF 261,360 $ 3.00 $ 784,080 6 acres = 6 x sf = SF Headworks concrete w/ trash racks CY 175 $ $ 87,500 concrete cost - depends on # of pipes Outlet works concrete w/ trash racks CY 175 $ $ 87,500 concrete cost - depends on # of pipes " subm. Elec. Pump EA 7 $ 1,300, $ 9,100,000 7 each 96" sbm. Elec. Pumps incl. 1 generator per pump Structural excavation Pipe & Pump Str. CY 19,500 $ $ 448, '+56' long x 150' wide x depth 10' for pipe and pump house Concrete Pipe, Prestressed (PCCP), 150,PSI, 96" LF 2455 $ $ 2,319,975 96" Pipe Structural excavation Power & Control Rm CY 667 $ $ 15, ' long x 30' wide x depth 5' for Power & Control Rm Stone Gabion Retaining Walls SY 3,583 $ $ 558,948 Gabion Box Systems,Gabions, galvanized steel mesh mats or boxes, stone filled Pump house 156'x49' + foundation SF 7,644 $ $ 5,350,800 $200/sf building + $500/sf foundation Power & Control House 80'x30' + foundation SF 2,400 $ $ 1,680,000 $200/sf building + $500/sf foundation Siphon / Environmental Flow Conduits LS 1 $ 100, $ 100,000 Siphon and conduits for einvironmental / low flow purposes Bring Electrical Power to Station AL 1 $ 1,000, $ 1,000,000 Osage Branch Crossing #2 Pump Station - Sub Total $ 22,032, % Contractor General Conditions % 30% (Subtotal of Amounts) $ 6,609, =(0.30 x subtotal) = A DART Add-On Allowance Contingencies % 32% (Subtotal of Amounts) $ 9,165, =(0.32 x [A+subtotal])=B Allocated Contingency % 20% (Subtotal of Amounts) $ 7,561, =(0.20 x [A+B+subtotal])=C Unallocated Contingency % 10% (Subtotal of Amounts) $ 4,536, =(0.10 x [A+B+C+subtotal]) Osage Branch Crossing #2 Pump Station - Total $ 49,906,565 McKamy Branch Pump Station UoM Quanity Unit Price Amount Comments Earthwork Channel CY 150,000 $ $ 1,500,000 Clearing and grubbing of channel and work sites Rock Environment Tree/Wetlands Mitigation SF 409,464 $ 3.00 $ 1,228, acres Headworks concrete w/ trash racks CY 720 $ $ 360,000 concrete cost - depends on # of pipes Outlet works concrete w/ trash racks CY 720 $ $ 360,000 concrete cost - depends on # of pipes " subm. Elec. Pump EA 24 $ 1,300, $ 31,200, each 96" sbm. Elec. Pumps incl. valves Structural excavation Pipe & Pump Str. CY 38,400 $ $ 883,200 For pipe and pump house Concrete Pipe, Prestressed (PCCP), 150,PSI, 144" LF 3,840 $ 1, $ 7,584, " Pipe Structural excavation Power & Control Rm CY 694 $ $ 15,962 Power & Control Rm Stone Gabion Retaining Walls SY 2,333 $ $ 363,948 Gabion Box Systems,Gabions, galvanized steel mesh mats or boxes, stone filled Pump house + foundation SF 8,176 $ $ 5,723,200 $200/sf building + $500/sf foundation Power & Control House + foundation SF 3,750 $ $ 2,625,000 $200/sf building + $500/sf foundation Siphon / Environmental Flow Conduits LS 1 $ 200, $ 200,000 Siphon and conduits for einvironmental / low flow purposes Bring Electrical Power to Station AL 1 $ 3,000, $ 3,000,000 McKamy Branch Pump Station - Sub Total $ 55,043, % Contractor General Conditions % 30% (Subtotal of Amounts) $ 16,513, =(0.30 x subtotal) = A

25 DART - Cotton Belt Regional Rail North Dallas Trench Option Pump Stations Rough Order of Magnitude Cost Estimate Estimate prepared by URS Date of Estimate : 12/22/2011 DART Add-On Allowance Contingencies % 32% (Subtotal of Amounts) $ 22,898, =(0.32 x [A+subtotal])=B Allocated Contingency % 20% (Subtotal of Amounts) $ 18,890, =(0.20 x [A+B+subtotal])=C Unallocated Contingency % 10% (Subtotal of Amounts) $ 11,334, =(0.10 x [A+B+C+subtotal]) McKamy Branch Pump Station - Total $ 124,680,590 Rail Trench Drainage UoM Quanity Unit Price Amount Comments Earthwork Channel CY 5,000 $ $ 50,000 Clearing and grubbing of channel and work sites Rock Environment Tree/Wetlands Mitigation SF 50,000 $ 3.00 $ 150, acres Rail Trench Drainage - Headworks concrete w/ trash racks CY 75 $ $ 37,500 concrete cost - depends on # of pipes Rail Trench Drainage - Outlet works concrete w/ trash racks CY 75 $ $ 37,500 concrete cost - depends on # of pipes Rail Trench Drainage - 96" subm. Elec. Pump EA 1 $ 1,300, $ 1,300,000 1 each 96" sbm. Elec. Pumps incl. valves Rail Trench Drainage - Structural excavation Pipe & Pump Str. CY 250 $ $ 5,750 For pipe and pump house Rail Trench Drainage - Concrete Pipe, Prestressed (PCCP), 150,PSI, 96" LF 100 $ $ 94,500 96" Pipe Rail Trench Drainage - Pump house + foundation SF 1,100 $ $ 770,000 $200/sf building + $500/sf foundation Stone Gabion Retaining Walls SY 500 $ $ 78,000 Gabion Box Systems,Gabions, galvanized steel mesh mats or boxes, stone filled Bring Electrical Power to Station AL 1 $ 1,000, $ 1,000,000 Trench Drain - Sub Total $ 3,523, % Contractor General Conditions % 30% (Subtotal of Amounts) $ 1,056, =(0.30 x subtotal) = A DART Add-On Allowance Contingencies % 32% (Subtotal of Amounts) $ 1,465, =(0.32 x [A+subtotal])=B Allocated Contingency % 20% (Subtotal of Amounts) $ 1,209, =(0.20 x [A+B+subtotal])=C Unallocated Contingency % 10% (Subtotal of Amounts) $ 725, =(0.10 x [A+B+C+subtotal]) Rail Trench Drainage - Total $ 7,980,584 Diesel Generator Backup for Pump Stations UoM Quanity Unit Price Amount Comments Clearing and grubbing of work site SF 50,000 $ 3.00 $ 150, acres Diesel Generator Building SF 24,750 $ $ 17,325,000 $200/sf building + $500/sf foundation (90' x 275') Diesel Powered Generator EA 1 $ 201, $ 201, kW Cummings Powered Diesel Generator Diesel Powered Generator EA 9 $ 456, $ 4,104, kW Cummings Powered Diesel Generator Diesel Fuel Storage Tank - 24 Full load Hrs EA 1 $ 100, $ 100,000 Horizontal,steel,double wall,above ground Fuel Storage Tank - 32,000 gallon capacity = 24 Full load Hrs Foundation for Diesel Storage tank SF 1,600 $ $ 480,000 $300/sf foundation Underground Power feed to Pump, Control from Back-up DG LS 1 $ 1,000, $ 1,000, Bring Electrical Power to Station AL 1 $ 1,000, $ 1,000,000 Diesel Generator Backup for Pump Stations - Sub Total $ 24,360, % Contractor General Conditions % 30% (Subtotal of Amounts) $ 7,308,000 =(0.30 x subtotal) = A DART Add-On Allowance Contingencies % 32% (Subtotal of Amounts) $ 10,133, =(0.32 x [A+subtotal])=B Allocated Contingency % 20% (Subtotal of Amounts) $ 8,360, =(0.20 x [A+B+subtotal])=C Unallocated Contingency % 10% (Subtotal of Amounts) $ 5,016, =(0.10 x [A+B+C+subtotal]) Diesel Generator Backup for Pump Stations - Total $ 55,178,323 Right-of-Way and Easement Requirements UoM Quanity Unit Price Amount Comments Right-of-Way and Easement Requirements LS 1 $ 3,000, $ 3,000,000 Right-of-Way and Easement Requirements - Total $ 3,000,000 Summary Amount Osage Branch Crossing #1 Pump Station - Total $ 47,366,900 Osage Branch Crossing #2 Pump Station - Total $ 49,906,565 McKamy Branch Pump Station - Total $ 124,680,590 Rail Trench Drainage - Total $ 7,980,584 Diesel Generator Backup for Pump Stations - Total $ 55,178,323 Right-of-Way and Easement Requirements - Total $ 3,000,000 Total $ 288,112,962

26 M A I N W O R K S H E E T - ROUGH ORDER OF MAGNITUDE COST ESTIMATE (Rev.13, June 1, 2010) DART - Cotton Belt Regional Rail Today's Date 12/22/11 North Dallas Trench Option Yr of $ 2011 Osage Branch Crossing #1 Pump Station Estimate Prepared by URS Yr of Revenue Ops Quantity w/o Contingency Allocated Contingency TOTAL Unit Cost Percentage of Construction Cost Percentage of Total Project Cost YOE Total 10 GUIDEWAY & TRACK ELEMENTS (route miles) $ - 0% 0% Guideway: At-grade exclusive right-of-way Guideway: At-grade semi-exclusive (allows cross-traffic) Guideway: At-grade in mixed traffic Guideway: Aerial structure Guideway: Built-up fill Guideway: Underground cut & cover Guideway: Underground tunnel Guideway: Retained cut or fill Track: Direct fixation Track: Embedded Track: Ballasted Track: Special (switches, turnouts) Track: Vibration and noise dampening STATIONS, STOPS, TERMINALS, INTERMODAL (number) $ - 0% 0% At-grade station, stop, shelter, mall, terminal, platform Aerial station, stop, shelter, mall, terminal, platform Underground station, stop, shelter, mall, terminal, platform Other stations, landings, terminals: Intermodal, ferry, trolley, etc Joint development Automobile parking multi-story structure Elevators, escalators SUPPORT FACILITIES: YARDS, SHOPS, ADMIN. BLDGS $ - 0% 0% Administration Building: Office, sales, storage, revenue counting Light Maintenance Facility Heavy Maintenance Facility Storage or Maintenance of Way Building Yard and Yard Track SITEWORK & SPECIAL CONDITIONS ,185 5,437 32,622 $ - 100% 0% 32, Demolition, Clearing, Earthwork Site Utilities, Utility Relocation 1, ,200 1, Haz. mat'l, contam'd soil removal/mitigation, ground water treatments Environmental mitigation, e.g. wetlands, historic/archeologic, parks Site structures including retaining walls, sound walls 18,327 3,665 21,993 21, Pedestrian / bike access and accommodation, landscaping Automobile, bus, van accessways including roads, parking lots Temporary Facilities and other indirect costs during construction 6,273 1,255 7,528 7, SYSTEMS $ - 0% 0% Train control and signals Traffic signals and crossing protection Traction power supply: substations Traction power distribution: catenary and third rail Communications Fare collection system and equipment Central Control Construction Subtotal (10-50) ,185 5,437 32,622 $ - 100% 0% 32, ROW, LAND, EXISTING IMPROVEMENTS $ - 0% Purchase or lease of real estate Relocation of existing households and businesses VEHICLES (number) $ - 0% Light Rail Heavy Rail Commuter Rail Bus Other Non-revenue vehicles Spare parts PROFESSIONAL SERVICES (applies to Cats ) ,699 1,740 10,439 $ - 32% 0% 10, Preliminary Engineering % Final Design 2, , % 3, Project Management for Design and Construction 2, , % 2, Construction Administration & Management 1, , % 2, Professional Liability and other Non-Construction Insurance , % 1, Legal; Permits; Review Fees by other agencies, cities, etc % Surveys, Testing, Investigation, Inspection % Start up % 0 Subtotal (10-80) ,884 7,177 43,061 $ - 0% 43, UNALLOCATED CONTINGENCY 4,306 0% 4, Contingency 3, ,306 Subtotal (10-90) ,367 $ - 0% 47, FINANCE CHARGES 0 0% 0 Total Project Cost (10-100) ,367 $ - 0% 47,367 Allocated Contingency as % of Base Yr w/o Contingency 20.00% Unallocated Contingency as % of Base Yr w/o Contingency 12.00% Total Contingency as % of Base Yr w/o Contingency 32.00% Unallocated Contingency as % of Subtotal (10-80) 10.00% YOE Construction Cost per Mile $0 YOE Total Project Cost per Mile Not Including Vehicles $0 YOE Total Project Cost per Mile $0

27 M A I N W O R K S H E E T - ROUGH ORDER OF MAGNITUDE COST ESTIMATE (Rev.13, June 1, 2010) DART - Cotton Belt Regional Rail Today's Date 12/22/11 North Dallas Trench Option Yr of $ 2011 Osage Branch Crossing #2 Pump Station Estimate Prepared by URS Yr of Revenue Ops Quantity w/o Contingency Allocated Contingency TOTAL Unit Cost Percentage of Construction Cost Percentage of Total Project Cost YOE Total 10 GUIDEWAY & TRACK ELEMENTS (route miles) $ - 0% 0% Guideway: At-grade exclusive right-of-way Guideway: At-grade semi-exclusive (allows cross-traffic) Guideway: At-grade in mixed traffic Guideway: Aerial structure Guideway: Built-up fill Guideway: Underground cut & cover Guideway: Underground tunnel Guideway: Retained cut or fill Track: Direct fixation Track: Embedded Track: Ballasted Track: Special (switches, turnouts) Track: Vibration and noise dampening STATIONS, STOPS, TERMINALS, INTERMODAL (number) $ - 0% 0% At-grade station, stop, shelter, mall, terminal, platform Aerial station, stop, shelter, mall, terminal, platform Underground station, stop, shelter, mall, terminal, platform Other stations, landings, terminals: Intermodal, ferry, trolley, etc Joint development Automobile parking multi-story structure Elevators, escalators SUPPORT FACILITIES: YARDS, SHOPS, ADMIN. BLDGS $ - 0% 0% Administration Building: Office, sales, storage, revenue counting Light Maintenance Facility Heavy Maintenance Facility Storage or Maintenance of Way Building Yard and Yard Track SITEWORK & SPECIAL CONDITIONS ,642 5,728 34,371 $ - 100% 0% 34, Demolition, Clearing, Earthwork Site Utilities, Utility Relocation 1, ,200 1, Haz. mat'l, contam'd soil removal/mitigation, ground water treatments Environmental mitigation, e.g. wetlands, historic/archeologic, parks Site structures including retaining walls, sound walls 19,749 3,950 23,698 23, Pedestrian / bike access and accommodation, landscaping Automobile, bus, van accessways including roads, parking lots Temporary Facilities and other indirect costs during construction 6,610 1,322 7,932 7, SYSTEMS $ - 0% 0% Train control and signals Traffic signals and crossing protection Traction power supply: substations Traction power distribution: catenary and third rail Communications Fare collection system and equipment Central Control Construction Subtotal (10-50) ,642 5,728 34,371 $ - 100% 0% 34, ROW, LAND, EXISTING IMPROVEMENTS $ - 0% Purchase or lease of real estate Relocation of existing households and businesses VEHICLES (number) $ - 0% Light Rail Heavy Rail Commuter Rail Bus Other Non-revenue vehicles Spare parts PROFESSIONAL SERVICES (applies to Cats ) ,166 1,833 10,999 $ - 32% 0% 10, Preliminary Engineering % Final Design 2, , % 3, Project Management for Design and Construction 2, , % 2, Construction Administration & Management 2, , % 2, Professional Liability and other Non-Construction Insurance 1, , % 1, Legal; Permits; Review Fees by other agencies, cities, etc % Surveys, Testing, Investigation, Inspection % Start up % 0 Subtotal (10-80) ,808 7,562 45,370 $ - 0% 45, UNALLOCATED CONTINGENCY 4,537 0% 4, Contingency 3, ,537 Subtotal (10-90) ,907 $ - 0% 49, FINANCE CHARGES 0 0% 0 Total Project Cost (10-100) ,907 $ - 0% 49,907 Allocated Contingency as % of Base Yr w/o Contingency 20.00% Unallocated Contingency as % of Base Yr w/o Contingency 12.00% Total Contingency as % of Base Yr w/o Contingency 32.00% Unallocated Contingency as % of Subtotal (10-80) 10.00% YOE Construction Cost per Mile $0 YOE Total Project Cost per Mile Not Including Vehicles $0 YOE Total Project Cost per Mile $0

28 M A I N W O R K S H E E T - ROUGH ORDER OF MAGNITUDE COST ESTIMATE (Rev.13, June 1, 2010) DART - Cotton Belt Regional Rail Today's Date 12/22/11 North Dallas Trench Option Yr of $ 2011 McKamy Branch Pump Station Estimate Prepared by URS Yr of Revenue Ops Quantity w/o Contingency Allocated Contingency TOTAL Unit Cost Percentage of Construction Cost Percentage of Total Project Cost YOE Total 10 GUIDEWAY & TRACK ELEMENTS (route miles) $ - 0% 0% Guideway: At-grade exclusive right-of-way Guideway: At-grade semi-exclusive (allows cross-traffic) Guideway: At-grade in mixed traffic Guideway: Aerial structure Guideway: Built-up fill Guideway: Underground cut & cover Guideway: Underground tunnel Guideway: Retained cut or fill Track: Direct fixation Track: Embedded Track: Ballasted Track: Special (switches, turnouts) Track: Vibration and noise dampening STATIONS, STOPS, TERMINALS, INTERMODAL (number) $ - 0% 0% At-grade station, stop, shelter, mall, terminal, platform Aerial station, stop, shelter, mall, terminal, platform Underground station, stop, shelter, mall, terminal, platform Other stations, landings, terminals: Intermodal, ferry, trolley, etc Joint development Automobile parking multi-story structure Elevators, escalators SUPPORT FACILITIES: YARDS, SHOPS, ADMIN. BLDGS $ - 0% 0% Administration Building: Office, sales, storage, revenue counting Light Maintenance Facility Heavy Maintenance Facility Storage or Maintenance of Way Building Yard and Yard Track SITEWORK & SPECIAL CONDITIONS ,557 14,311 85,868 $ - 100% 0% 85, Demolition, Clearing, Earthwork 1, ,800 1, Site Utilities, Utility Relocation 3, ,600 3, Haz. mat'l, contam'd soil removal/mitigation, ground water treatments Environmental mitigation, e.g. wetlands, historic/archeologic, parks 1, ,474 1, Site structures including retaining walls, sound walls 49,315 9,863 59,178 59, Pedestrian / bike access and accommodation, landscaping Automobile, bus, van accessways including roads, parking lots Temporary Facilities and other indirect costs during construction 16,513 3,303 19,816 19, SYSTEMS $ - 0% 0% Train control and signals Traffic signals and crossing protection Traction power supply: substations Traction power distribution: catenary and third rail Communications Fare collection system and equipment Central Control Construction Subtotal (10-50) ,557 14,311 85,868 $ - 100% 0% 85, ROW, LAND, EXISTING IMPROVEMENTS $ - 0% Purchase or lease of real estate Relocation of existing households and businesses VEHICLES (number) $ - 0% Light Rail Heavy Rail Commuter Rail Bus Other Non-revenue vehicles Spare parts PROFESSIONAL SERVICES (applies to Cats ) ,898 4,580 27,478 $ - 32% 0% 27, Preliminary Engineering % Final Design 7,299 1,460 8, % 8, Project Management for Design and Construction 5,796 1,159 6, % 6, Construction Administration & Management 5,009 1,002 6, % 6, Professional Liability and other Non-Construction Insurance 2, , % 3, Legal; Permits; Review Fees by other agencies, cities, etc % Surveys, Testing, Investigation, Inspection 1, , % 1, Start up % 0 Subtotal (10-80) ,455 18, ,346 $ - 0% 113, UNALLOCATED CONTINGENCY 11,335 0% 11, Contingency 9,445 1,889 11,335 Subtotal (10-90) ,681 $ - 0% 124, FINANCE CHARGES 0 0% 0 Total Project Cost (10-100) ,681 $ - 0% 124,681 Allocated Contingency as % of Base Yr w/o Contingency 20.00% Unallocated Contingency as % of Base Yr w/o Contingency 12.00% Total Contingency as % of Base Yr w/o Contingency 32.00% Unallocated Contingency as % of Subtotal (10-80) 10.00% YOE Construction Cost per Mile $0 YOE Total Project Cost per Mile Not Including Vehicles $0 YOE Total Project Cost per Mile $0

29 M A I N W O R K S H E E T - ROUGH ORDER OF MAGNITUDE COST ESTIMATE (Rev.13, June 1, 2010) DART - Cotton Belt Regional Rail Today's Date 12/22/11 North Dallas Trench Option Yr of $ 2011 Rail Trench Drainage Estimate Prepared by URS Yr of Revenue Ops Quantity w/o Contingency Allocated Contingency TOTAL Unit Cost Percentage of Construction Cost Percentage of Total Project Cost YOE Total 10 GUIDEWAY & TRACK ELEMENTS (route miles) $ - 0% 0% Guideway: At-grade exclusive right-of-way Guideway: At-grade semi-exclusive (allows cross-traffic) Guideway: At-grade in mixed traffic Guideway: Aerial structure Guideway: Built-up fill Guideway: Underground cut & cover Guideway: Underground tunnel Guideway: Retained cut or fill Track: Direct fixation Track: Embedded Track: Ballasted Track: Special (switches, turnouts) Track: Vibration and noise dampening STATIONS, STOPS, TERMINALS, INTERMODAL (number) $ - 0% 0% At-grade station, stop, shelter, mall, terminal, platform Aerial station, stop, shelter, mall, terminal, platform Underground station, stop, shelter, mall, terminal, platform Other stations, landings, terminals: Intermodal, ferry, trolley, etc Joint development Automobile parking multi-story structure Elevators, escalators SUPPORT FACILITIES: YARDS, SHOPS, ADMIN. BLDGS $ - 0% 0% Administration Building: Office, sales, storage, revenue counting Light Maintenance Facility Heavy Maintenance Facility Storage or Maintenance of Way Building Yard and Yard Track SITEWORK & SPECIAL CONDITIONS , ,496 $ - 100% 0% 5, Demolition, Clearing, Earthwork Site Utilities, Utility Relocation 1, ,200 1, Haz. mat'l, contam'd soil removal/mitigation, ground water treatments Environmental mitigation, e.g. wetlands, historic/archeologic, parks Site structures including retaining walls, sound walls 2, ,788 2, Pedestrian / bike access and accommodation, landscaping Automobile, bus, van accessways including roads, parking lots Temporary Facilities and other indirect costs during construction 1, ,268 1, SYSTEMS $ - 0% 0% Train control and signals Traffic signals and crossing protection Traction power supply: substations Traction power distribution: catenary and third rail Communications Fare collection system and equipment Central Control Construction Subtotal (10-50) , ,496 $ - 100% 0% 5, ROW, LAND, EXISTING IMPROVEMENTS $ - 0% Purchase or lease of real estate Relocation of existing households and businesses VEHICLES (number) $ - 0% Light Rail Heavy Rail Commuter Rail Bus Other Non-revenue vehicles Spare parts PROFESSIONAL SERVICES (applies to Cats ) , ,759 $ - 32% 0% 1, Preliminary Engineering % Final Design % Project Management for Design and Construction % Construction Administration & Management % Professional Liability and other Non-Construction Insurance % Legal; Permits; Review Fees by other agencies, cities, etc % Surveys, Testing, Investigation, Inspection % Start up % 0 Subtotal (10-80) ,046 1,209 7,255 $ - 0% 7, UNALLOCATED CONTINGENCY 726 0% Contingency Subtotal (10-90) ,981 $ - 0% 7, FINANCE CHARGES 0 0% 0 Total Project Cost (10-100) ,981 $ - 0% 7,981 Allocated Contingency as % of Base Yr w/o Contingency 20.00% Unallocated Contingency as % of Base Yr w/o Contingency 12.00% Total Contingency as % of Base Yr w/o Contingency 32.00% Unallocated Contingency as % of Subtotal (10-80) 10.00% YOE Construction Cost per Mile $0 YOE Total Project Cost per Mile Not Including Vehicles $0 YOE Total Project Cost per Mile $0