Final - Preliminary Design Report Interstate 10 and Indian Avenue Area Sewer System. Prepared for

Transcription

1 Final - reliminary Design Report Interstate 10 and Indian Avenue Area Sewer System repared for Mission Springs Water District July 2012

2 Mission Springs Water District I-10 & Indian Area Sewer System DR Table of Contents TABLE OF CONTENTS SECTION 1 Introduction Background 1-1 Scope of Work 1-1 SECTION 2 Design Criteria Average Day Sewer Flow 2-1 eak Flow 2-1 Infiltration and Inflow 2-2 ipe Design Criteria 2-2 Manhole Design Criteria 2-3 SECTION 3 Hydraulic Analysis Model Development 3-1 Model Loads 3-1 Analysis Results 3-1 SECTION 4 roposed Facilities Alternative 1 - roposed Trunk Lines and Sewer Lift Station 4-1 roposed Collector Lines 4-4 Right-of-Way and Easements 4-4 Alternative 2 - roposed Trunk Lines and Sewer Lift Station 4-5 roposed Collector Lines 4-8 Right-of-Way and Easements 4-8 SECTION 5 Conclusions and Recommendations Average Day and eak Sewer Flows 5-1 roposed Facilities 5-1 Alternative Comparison 5-4 Recommendation 5-5 R:\WO\2011\ \Report\DR Body 2.docx i

3 Mission Springs Water District I-10 & Indian Area Sewer System DR Table of Contents List of Tables Table 2-1 Non-Residential MSWD Design Unit Flow Values Table 2-2 Estimated Flows Table 2-3 MSWD Wet Weather eak Factors Table 4-1 eak Flow Conditions for Sewage Lift Station Table 4-2 eak Flow Conditions for Sewage Lift Station List of Figures and lates Figure 1 - I-10 and Indian Ave. Area Sewer System Study Area late 1 - Tributary Area Map late 2 Sewer Model Results Alternative 1 late 3 Sewer Model Results Alternative 2 List of Exhibits Appendix A Tributary Areas and Estimated Wastewater Flows Appendix B - Model Outputs Appendix C - Construction Cost Estimates R:\WO\2011\ \Report\DR Body 2.docx ii

4 Mission Springs Water District Section 1 I-10 & Indian Area Sewer System DR Introduction SECTION 1 Introduction The following preliminary design report has been prepared in accordance with Webb s roposal for lanning and Design Engineering Services I-10 and Indian Area Sewer System, dated July Final design for the sewer improvements will be based on the criteria and findings provided in this report, as directed by Mission Springs Water District (MSWD). Background There are over 5,000 septic systems on record with MSWD. Most are active all year long with the remaining operated seasonally when part-time residents occupy dwellings during the mild winters. The underlying thermal and cold ground water sub basins are an important asset to the area for both the recreational spas and, most importantly, as the only water supply source for MSWD. In addition to existing residential units, future development within MSWD s service area is anticipated. resently the Interstate 10 (I-10) and Indian Ave. area is provided water service from MSWD and sewer service is provided through the use of private septic tank systems. Additional development is planned in the area but is stymied at this time due to the current economic conditions. In addition to the economy, the Regional Board has refused to permit some applicants due to concerns over additional septic tanks in the area. This report is to supplement the current Master Sewer lan to allow MSWD to readily provide and have implemented the ultimate sewer system for the anticipated pending developments in the study area. er the April 2007 Wastewater System Comprehensive Master lan (Master lan), MSWD ultimately plans to convey wastewater to a new Regional Wastewater Treatment lant (RWWT) located on Little Morongo Road near I-10. The I-10 and Indian Area will ultimately be served by this regional wastewater treatment facility. A benefit Assessment District is being analyzed for the study area as shown on Figure 1. The requested sewer designs consist of approximately 33,000 to 34,000 linear feet of sewer pipe and a lift station(s). The project study area is generally bounded by 18th Ave. to the north, Little Morongo Road to the east, the railroad right of way to the south, and Karen Ave to the west. The natural topography slopes down from the north to the south except for the south east corner of the study area which has rolling hills. Outside of the study boundary to the west and north are wind farms and are not anticipated to generate wastewater tributary to the study area. South of the study boundary and the rolling hills within the boundary are within the Coachella Valley Multiple Species Habitat Conservation which at this time are not developable. Further north of the wind farms are planned residential developments that will generate wastewater. Wastewater generated in this region will contribute to the wastewater flow in the proposed 19 th Ave. trunk line at the Indian Avenue intersection and is discussed in Section 3. Scope of Work To accomplish the objectives of this report, the scope of the study includes the following: 1. Specify hydraulic design constraints 2. Identify the existing and potential tributary wastewater loads 3. Develop and analyze a hydraulic model of the proposed wastewater system 4. Discus right-of-way and easement requirements 5. rovide conclusions and recommendations 1-1

5 GARNET AVE 18TH AVE KAREN AVE HALLECK RD N INDIAN CANYON DR 19TH AVE WWT ORR WAY MC LANE ST RUERT ST NEWHALL ST 20TH AVE LITTLE MORONGO RD. LEGEND Study Area WWT Boundary INDIAN AVE 10 EST DR Sources: Eagle Aerial, March 2010; County of Riverside, O 0 1,000 2,000 3,000 Feet G:\2011\ \GIS\Figure 1 Site Map.mxd Figure 1 I-10 and Indian Ave. Area Sewer System Study Area

6 Mission Springs Water District Section 2 I-10 & Indian Area Sewer System DR Design Criteria SECTION 2 Design Criteria The design criteria for this report were based on the Wastewater Master lan and Developer Handbook for MSWD. Average Day Sewer Flow Existing average day flows are based on average annual water meter data provided by the MSWD. It was assumed that 80% of the water will return to the sewer system. For ultimate conditions, average daily flows were based on developer estimates where available and landuse data for all other areas. Three landuse types are designated within the study area of this report. The unit values for flow generation for these landuse types are provided in Table 2-1 and are identical to the 2007 Master lan. Table 2-1 Non-Residential MSWD Design Unit Flow Values Land Use Unit Flow (gpd/acre) Medium Density Residential (5 edu/ac x 200 gpd/edu) 1,000 Commercial 2,000 Industrial 2,000 Existing and ultimate average day flow estimates are provided in Table 2-2. For a detailed breakdown of the estimated flow per development area, refer to the tables provided in Appendix A. Table 2-2 Estimated Flows Estimated Flows Gallons per Day Existing 48,122 Ultimate 1,583,680 As requested by the District, the equivalent EDU s for the service area, based on a residential EDU (200 gpd) is approximately 7,900 EDUs. The service area evaluated in this report consists mainly of Commercial/Industrial properties, thus the EDU equivalent will be less, a more detailed evaluation of the equivalent EDUs will be provided during financing discussions with the District. eak Flow eak flows were based on peaking factors from the April 2007 Master lan and are provided as Table 2-3. Average day flows are multiplied by peak factors to obtain estimated peak flows. A typical diurnal curve will have two high time periods with higher than average flow, usually one in the early morning and a second in the evening. The peak factor accounts for these high flow periods. 2-1

7 Mission Springs Water District Section 2 I-10 & Indian Area Sewer System DR Design Criteria Table 2-3 MSWD Wet Weather eak Factors Average Flow (mgd) eak Factor Infiltration and Inflow Infiltration and inflow were assumed to be negligible because the sewer being analyzed will be: New construction Utilize pipes with improved joints Build in a hot dry climate Area has a deep water table ipe Design Criteria ipeline sizing was based on design criteria outlined in the Developers Handbook, alternative maximum depth to diameter ratios were provided by the District for this project, which are as follows: ipe Material: VC Manning s Roughness Coefficient: n = Maximum depth to diameter ratio: 50% (8-inch dia. pipes) 75% (10-inch dia. pipes and greater) Minimum Velocity: 2 fps Maximum Velocity: 10 fps The proposed pipeline alignments will be within existing street right-of-ways. As agreed upon during the August 30, 2011 project kick off meeting, the proposed alignments will be located on the southerly or westerly side of the street, 6-feet from the street centerline as permitted by the location of existing utilities. Location of the sewer lines shall not interfere with other existing utilities. 2-2

8 Mission Springs Water District Section 2 I-10 & Indian Area Sewer System DR Design Criteria Manhole Design Criteria Manholes will be designed in accordance to the guidelines provided in the Developers Handbook which is summarized below: Maximum Manhole Spacing Manhole Diameter Manhole Drops 350 ft 48 inch (less than 12 and for 18 dia. piping and smaller) 60 inch (deeper than 12 and for 18 dia. piping and greater) 0.1 ft on straight runs 0.2 ft for 90 bends Manholes are to be designed at: All grade breaks Changes in horizontal alignment Changes in sewer diameter Street intersections Sewer pipe intersections Connections with laterals larger than 6 in diameter Beginning of sewer runs such as cul-de-sacs. 2-3

9 Mission Springs Water District Section 3 I-10 & Indian Area Sewer System DR Hydraulic Analysis SECTION 3 Hydraulic Analysis Model Development A digital model of two (2) alternative wastewater conveyance systems, identified as Alternative 1 and Alternative 2, were prepared by Webb Associates using SewerCAD. Loads, peaking table, and design criteria were input into the model. Model scenarios were analyzed under peak flow conditions to verify that the proposed systems could accommodate peak flow while staying within the deign constraints. Aerial topographic survey data was used to determine manhole rim elevations. As-built plans were used to determine the flow line invert elevation for the existing 12-inch diameter sewer line from the south side of Interstate 10, which is 29.4 feet deep. The modeling software has the capabilities to calculate a preliminary design for proposed sewer lines based on the design constraints adopted by MSWD. This design feature was utilized to determine the proposed pipe sizes for the two (2) alternative conveyance systems. Model Loads The study area was divided up into tributary areas based on the topography of the existing ground surface and the anticipated location of future collection lines. Estimated wastewater flows were calculated within each tributary boundary and these flows were then assigned to the nearest downstream manhole. late 1 shows the tributary boundaries used to load the model and calculated flows for each tributary boundary can be found in Appendix A. According to the Master lan update, dated October 24, 2008, a 21-inch diameter trunk line used to convey wastewater generated north of the study area will tie into the proposed 19 th Avenue trunk line at Indian Avenue. An assumption was made that this 21-inch diameter trunk line was designed to carry wastewater at a minimum slope of at a depth to diameter ratio of 75% which equates to a peak flow rate of 2.95 MGD. Therefore, this additional flow from the north was added to the manhole at the intersection of Indian Avenue and 19 th Avenue. It was assumed that no additional flows outside of the study area needed to be included in the sizing of the proposed 20th Avenue trunk line. Analysis Results eak flow was used in the models to determine the minimum allowable pipe diameter size for each segment base on the design criteria previously addressed. The minimum pipe diameter sizes for Alternative 1 are shown on late 2 and the pipe diameter sizes for Alternative 2 are shown on late 3. A nodal map and model output data for both Alternatives are provided in Appendix B. 3-1

10 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities SECTION 4 roposed Facilities Alternative 1 - roposed Trunk Lines and Sewer Lift Station The following wastewater pipelines have been sized based on the hydraulic analysis previously addressed. Future developments will dictate the sequence these improvements will be constructed in. 19 th Avenue Trunk Line Wastewater generated north of 19 th Avenue will be collected and conveyed to the proposed RWWT by means of the 19th Ave. Trunk. This proposed trunk line will commence near the intersection of Halleck Rd. and 19th Ave and continue east along 19th Ave. to the proposed RWWT just west of Little Morongo Rd. The pipe diameter will range between 8 to 24 inches and span approximately 9,300 linear feet as shown on late 2. The portion of the 19 th Avenue Trunk line east of Indian Avenue (5,300 LF) will primarily be utilized to convey wastewater generated north of the study area to the RWWT, therefore costs associated with over sizing of this portion of the trunk line will be paid for by the District with reimbursement agreements for future development and/or connections. Over sizing costs are estimated at $260, th Avenue Trunk Line and Sewage Lift Station A proposed trunk line in 20 th Avenue will be utilized to convey wastewater generated between 19 th Avenue and 20 th Avenue within the study area. The 20 th Avenue Trunk line is proposed between Karen Ave. and just west of Indian Avenue where a sewage lift station will be required to pump flow under the recently completed Indian Avenue and Interstate 10 overpass, across Indian Avenue. Otherwise, the trunk line would need to be installed at a depth of approximately feet below ground surface and would require that the recently completed improvements be disturbed. East of Indian Avenue, the force main from the sewage lift station will terminate and the 20 th Avenue Trunk line will continue to Little Morongo Road. The 20 th Avenue Trunk line will range in size between 8 to 21 inches in diameter as the projected flows increase from west to east. This line will be approximately 11,000 feet in length and will terminate at a proposed lift station near the intersection of 20 th Ave. and Little Morongo Road that will be part of the future RWWT. This lift station will be designed and constructed as part of the RWWT roject; however preliminary costs for the lift station have been included in this report. Flow variations between existing to ultimate flow conditions are significant for this project and specifically in the area of the proposed lift station. Table 4-1 below summarizes two peak flow conditions to be considered. Table 4-1 eak Flow Conditions for Sewage Lift Station Flow Condition Situation Flow Condition 1 Existing Influent eak Flows 20 gpm Condition 2 Ultimate Influent eak Flows 700 gpm It is noted that utilizing an 8-inch diameter pipe at 700 gpm yields a velocity of 4.5 fps. Utilizing a 6-inch diameter pipe at the same flow yields a higher velocity of 7.9 fps, which is considered to be too high for a sewer forcemain. Due to the range of flows from existing to projected ultimate flows, it is recommended that an 8-inch forcemain be utilized for crossing the Indian Avenue and 20 th Avenue 4-1

11 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities intersection. Minimum flow to maintain a velocity above 2.5 fps in an 8-inch forcemain is approximately 400 gpm. reliminary hydraulic calculations indicate that the pumps will be approximately 10 hp units. Due to the current and ultimate flow variations the wet well volume, pump motor sizing, electrical requirement, valves and pipe fittings will be affected by the flow requirements necessary to maintain the proper flushing velocity in the selected discharge forcemain, while avoiding the necessity of installing two different sized forcemains to meet current and ultimate flows. Sizing the lift station too large could result in long sewer detention times in the wet well and shorter pumping durations which may lead to potential odor control problems. Sizing the lift station too small may accommodate current flows, but will restrict future expansion. It will be necessary to design the lift station with the flexibility to pump current flows and accommodate future flows or provide for future expansion. Overall Lift Station Standards shall be in accordance with those identified in the Master lan. The following discussion will evaluate two (2) station configurations. One option (Option 1) consists of equipping the lift station with the electrical equipment and conduits and larger sized wet well for ultimate influent flow conditions and utilizing lower flow pumping units until flows exceed their primary pumping capacity. umping units and breakers will be replaced with larger units as flow conditions increase due to future developments. It is not recommended to utilize current flow potential (700 gpm total influent peak flow) to size the initial pumping units, due to minimal flow during initial start up and operations. The pumping units should be sized lower than the current flow potential but higher than the initial flow conditions. If this option was selected, we recommend that the initial pumping units have a minimum pumping capacity of 400 gpm each. rior planning must be conducted as the flow conditions increase closer to the capacity of the initial pumping units. Careful flow monitoring and pump run time records must be kept to determine when the change out will take place. Another option (Option 2) is to equip the lift station with three (3) VFD pumping units (each 400 gpm) and the wet well will be sized for an intermediate flow condition, thus reducing its size. The utilization of three (3) pumping units will forego the required pump and breaker change out as in Option 1. The VFD will be set on manual control thus maintaining a set flow rate for the pumping units. Operations of this lift station configuration, in manual mode, will be similar to a typical start/stop lift station. The pump s flow rate may be manually adjusted by adjusting the VFD to meet increasing flow conditions at infinitely variable increments. At a certain intermediate flow condition and as flows are more consistent, the lift station may be switched to automatic level control and operate as a traditional VFD controlled lift station. The station will not require a large sized wet well for ultimate conditions because the pumping units will automatically ramp up to meet these conditions. Forcemain and Initial umping Flow Rate It is noted that a flow rate of 400 gpm is required in order to maintain a minimum velocity of 2.6 fps when utilizing an 8-inch diameter forcemain. It is noted that if two 400 gpm pumps are on with a combined estimated flow rate of gpm, the forcemain velocity will be 5.1 fps, just below the recommended maximum of 6.0 fps. In order to meet lower flow rate conditions, yet provide for forcemain flushing capabilities, it is recommended to size the initial pumping units for a minimum flushing flow rate of 400 gpm. Therefore, when one pump is on, the flow rate is closer to the lower flow condition of 20 gpm and when two pumps are on, to provide for a combined flow rate of approximately 800 gpm, the forcemain velocities will be adequate for flushing while utilizing a 8-inch forcemain within these ranges. 4-2

12 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities Wet Well Configuration In order to meet build out flow conditions, it is recommended to provide for a wet well sizing based on this condition with a flow rate of 700 gpm. For build out flow conditions, an 8-foot diameter precast concrete wet well is recommended with a 5-foot control band. This will provide for a pump station operation less than 6 cycles per hour under all flow conditions through 700 gpm. As previously discussed, a minimum pumping unit of 400 gpm is recommended for the initial start up and flow conditions. A separate precast concrete vault will be constructed adjacent to the wet well to house shut-off and check valves and connection piping. Standby generators or a quick connect in the electrical panel will be provided in cases there is a power failure. Lift Station Appurtenances All lift station appurtenances will be designed for ultimate flow conditions, such as: Electrical o Breakers (sized for initial pumping unit size in Option 1) o Electrical Service o Switches o Starters o Controls o Motor control center Mechanical o iping and fittings o lug and Check Valves o Structures and vaults o umping unit lifting rails Site layout of lift station will accommodate all lift station equipment, wet well, vaults, etc. for ultimate buildout conditions. ump lifting rails will be designed to lift pumping units designed for ultimate conditions. Lift Station Location We have established a preliminary location for the lift station north of 20 th Avenue and west of Indian Avenue, located near the existing Motel 6 (see late 2). The lift station can be placed in the street parkway or on private property with an easement. If placed in the street right-of-way the District would be subject to County/City jurisdiction and control. urchasing a site for the lift station would guarantee the District control in the future. Garnet Avenue Trunk Line The Garnet Avenue Trunk line is proposed to convey wastewater generated within the study area on the south side of Interstate 10 to the 20 th Avenue Trunk line on the north side of Interstate 10. As shown on late 2, this trunk line commences west of Indian Avenue along Garnet Street and traverses east to an existing 12-inch dia. sewer line under Interstate 10. Based on the as-built drawings, the design capacity for the existing 12-inch dia. Sewer line is 0.81 mgd and the ultimate peak flow for this line under Alternative 1 is 0.5 mgd. This trunk line will range in size from 8-inches to 12-inches in diameter and approximately 6,600 feet long. 4-3

13 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities roposed Collector Lines Rupert Street The proposed 8-inch diameter collector line in Rupert Street will extend approximately 1,700 lf from the south side of 19 th Avenue to the 20th Avenue Trunk line to the south. McLane Street Approximately 1,300 lf of 8-inch collection line is needed along McLane Street between 19 th Ave and Orr Way. Newhall Street Approximately 1,300 lf of 8-inch collection line is needed along Newhall Street between 19 th Ave and Orr Way. Orr Way An 8-inch diameter wastewater line is needed to connect the proposed collector lines in McLane St. and Newhall St. to the collector line in Rupert Street. Approximately 800 ft of pipeline will be needed. North Indian Avenue On the north side of the I-10 Freeway, a collector line is needed in Indian Ave. between 19th Ave. and the proposed 20th Ave. Trunk line. About 1,500 ft of 8-inch diameter pipe is needed for this connection. South Indian Avenue Collector Due to the topography south of the I-10 Freeway along Indian Avenue, properties south of Garnet Ave. will not flow to the north by gravity and will therefore require a lift station. Industrial Complex Collector East of Indian Avenue and north of 20 th Avenue there are existing and proposed developments along an unnamed street. A proposed 8-inch diameter collector approximately 2,100 ft long is proposed along this street to convey wastewater generated in this area to the proposed 20 th Avenue Trunk line. Due to low flows generated within the complex, the velocity in the 8-inch diameter sewer will be less than 2.0 ft/s. Right-of-Way and Easements The proposed pipeline alignments will be within existing street right-of-way. However, the 20 th Avenue Trunk, Garnet Avenue Trunk, and the collectors on Indian Avenue will cross through Caltrans right-ofway at Indian Avenue. Discussions between MSWD staff and Caltrans are underway to establish an agreement between the two entities. It is likely that a jack and boar through these sections will be required. 4-4

14 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities Alternative 2 - roposed Trunk Lines and Sewer Lift Station The following wastewater pipelines have been sized based on the hydraulic analysis previously addressed. Future developments will dictate the sequence these improvements will be constructed in. 19 th Avenue Trunk Line Wastewater generated north of 19 th Avenue and west of Indian Avenue will be collected and conveyed south, under Interstate 10 to Garnet Avenue, where it will then go back under Interstate 10 into a proposed lift station on 20 th Avenue. The pipe diameters will range in size from 8 inches to 10 inches and span approximately 2,800 linear feet as shown on late 3. Wastewater generated north of 19 th Avenue and east of Indian Avenue will be collected and conveyed to the proposed RWWT by means of the 19th Ave. Trunk. This proposed trunk line will commence near the intersection of Indian Avenue and 19th Ave and continue east along 19th Ave. to the proposed RWWT just west of Little Morongo Rd. The pipe diameter will be 24 inches and span approximately 5,300 linear feet as shown on late 3. The portion of the 19 th Avenue Trunk line east of Indian Avenue (5,300 LF) will primarily be utilized to convey wastewater generated north of the study area to the RWWT, therefore costs associated with over sizing of this portion of the trunk line will be paid for by the District with reimbursement agreements for future development and/or connections. Over sizing costs are estimated at $251, th Avenue Trunk Line and Sewage Lift Station A proposed trunk line in 20 th Avenue will be utilized to convey wastewater generated between 19 th Avenue and 20 th Avenue within the study area. Similar to the 19 th Avenue Trunk Line, wastewater generated between 19 th Avenue and 20 th Avenue and west of Indian Avenue will be collected and conveyed south, under Interstate 10 to Garnet Avenue. The western portion of 20 th Avenue Trunk line will range in size between 8 to 15 inches in diameter and will be approximately 4,100 feet in length. The eastern portion of the proposed trunk line in 20 th Avenue will be utilized to convey wastewater generated between 19 th Avenue and 20 th Avenue, and east of Indian Avenue. The eastern portion of the 20 th Avenue Trunk line is proposed between Indian Avenue and the existing 12 inch diameter sewer line under Interstate 10 where a sewage lift station will be required to pump flow to the RWWT. The eastern portion of the 20 th Avenue Trunk line will range in size from 8 to 18 inches in diameter and will be approximately 4,800 feet in length as shown on late 3. Flow variations between existing to ultimate flow conditions are significant for this project and specifically in the area of the proposed lift station. Table 4-2 below summarizes two peak flow conditions to be considered. Table 4-2 eak Flow Conditions for Sewage Lift Station Flow Condition Situation Flow Condition 1 Existing Influent eak Flows 90 gpm Condition 2 Ultimate Influent eak Flows 2,300 gpm Due to the range of flows from existing to projected ultimate flows, it is recommended that an 12-inch forcemain be utilized for the proposed lift station. Minimum flow to maintain a velocity above 2.5 fps in 4-5

15 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities an 12-inch forcemain is approximately 900 gpm. reliminary hydraulic calculations indicate that the pumps will be approximately 40 hp units. Due to the current and ultimate flow variations the wet well volume, pump motor sizing, electrical requirement, valves and pipe fittings will be affected by the flow requirements necessary to maintain the proper flushing velocity in the selected discharge forcemain, while avoiding the necessity of installing two different sized forcemains to meet current and ultimate flows. Sizing the lift station too large could result in long sewer detention times in the wet well and shorter pumping durations which may lead to potential odor control problems. Sizing the lift station too small may accommodate current flows, but will restrict future expansion. It will be necessary to design the lift station with the flexibility to pump current flows and accommodate future flows or provide for future expansion. The following discussion will evaluate two (2) station configurations. One option (Option 1) consists of equipping the lift station with the electrical equipment and conduits and larger sized wet well for ultimate influent flow conditions and utilizing lower flow pumping units until flows exceed their primary pumping capacity. umping units and breakers will be replaced with larger units as flow conditions increase due to future developments. It is not recommended to utilize current flow potential (2,300 gpm total influent peak flow) to size the initial pumping units, due to minimal flow during initial start up and operations. The pumping units should be sized lower than the current flow potential but higher than the initial flow conditions. If this option was selected, we recommend that the initial pumping units have a minimum pumping capacity of 500 gpm each. rior planning must be conducted as the flow conditions increase closer to the capacity of the initial pumping units. Careful flow monitoring and pump run time records must be kept to determine when the change out will take place. Another option (Option 2) is to equip the lift station with three (3) VFD pumping units (each 1,150 gpm) and the wet well will be sized for an intermediate flow condition, thus reducing its size. The utilization of three (3) pumping units will forego the required pump and breaker change out as in Option 1. The VFD will be set on manual control thus maintaining a set flow rate for the pumping units. Operations of this lift station configuration, in manual mode, will be similar to a typical start/stop lift station. The pump s flow rate may be manually adjusted by adjusting the VFD to meet increasing flow conditions at infinitely variable increments. At a certain intermediate flow condition and as flows are more consistent, the lift station may be switched to automatic level control and operate as a traditional VFD controlled lift station. The station will not require a large sized wet well for ultimate conditions because the pumping units will automatically ramp up to meet these conditions. Forcemain and Initial umping Flow Rate It is noted that a flow rate of 900 gpm is required in order to maintain a minimum velocity of 2.5 fps when utilizing an 12-inch diameter forcemain. It is noted that if two 1,150 gpm pumps are on with a combined estimated flow rate of 2,200-2,300 gpm, the forcemain velocity will be 6.5 fps, slightly above the recommended maximum of 6.0 fps. In order to meet lower flow rate conditions, yet provide for forcemain flushing capabilities, it is recommended to size the initial pumping units for a minimum flushing flow rate of 900 gpm. Wet Well Configuration In order to meet build out flow conditions, it is recommended to provide for a wet well sizing based on this condition with a flow rate of 2,300 gpm. For build out flow conditions, a structurally engineered

16 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities foot deep concrete wet well will be required to accommodate the existing invert elevation (29.4 bgs) of the 12-inch diameter sewer line under Interstate 10. A separate precast concrete vault will be constructed adjacent to the wet well to house shut-off and check valves and connection piping. Standby generators or a quick connect in the electrical panel will be provided in cases there is a power failure. Lift Station Appurtenances All lift station appurtenances will be designed for ultimate flow conditions, such as: Electrical o Breakers (sized for initial pumping unit size in Option 1) o Electrical Service o Switches o Starters o Controls o Motor control center Mechanical o iping and fittings o lug and Check Valves o Structures and vaults o umping unit lifting rails Site layout of lift station will accommodate all lift station equipment, wet well, vaults, etc. for ultimate buildout conditions. ump lifting rails will be designed to lift pumping units designed for ultimate conditions. Lift Station Location The location of the lift station will be located on 20 th Avenue where the existing 12-inch diameter sewer crosses Interstate 10 (see late 3). It is recommended that the lift station be placed on property owned by the District to ensure control of the property in the future. Garnet Avenue Trunk Line The Garnet Avenue Trunk line is proposed to convey wastewater generated within the study area from north of Interstate 10 and west of Indian Avenue and on the south side of Interstate 10 to the 20 th Avenue Trunk line on the north side of Interstate 10. A jack and bore under Interstate 10 would be required to convey wastewater from north of Interstate 10 to the Garnet Street Trunk line. As shown on late 3, this trunk line commences west of Indian Avenue along Garnet Street and traverses east to an existing 12-inch dia. sewer line under Interstate 10. This trunk line will range in size from 8 to 18-inches in diameter and approximately 6,600 feet long. The sewer model indicates that the portion of the Garnet Avenue Trunk line upstream of the jack and bore under Interstate 10 will have a velocity of less than 2.0 ft/s under Alternative 2. As indicated previously, the design capacity for the existing 12-inch dia. sewer line is 0.81 mgd and the ultimate peak flow for this line under Alternative 2 is 1.84 mgd; therefore this line will be surcharged once ultimate peak flows exceed 0.81 mgd. Ultimate peak flows will approach 0.81 mgd when there are approximately 1,500 EDUs (300,000 mgd average day flows) existing to the west of Indian Avenue, between Interstate 10 and 18 th Avenue, and the entire area south of Interstate 10 which contributes flow to this portion of the sewer collection system. Flows and EDUs should be monitored by the District to evaluate when the existing 12-inch dia. sewer line is approaching design capacity. 4-7

17 Mission Springs Water District Section 4 I-10 & Indian Area Sewer System DR roposed Facilities roposed Collector Lines Rupert Street The proposed 8-inch diameter collector line in Rupert Street will extend approximately 1,200 lf from the south side of 19 th Avenue to Orr Way and approximately 500 lf of 12-inch diameter collector line will extend from Orr Way to the 20th Avenue Trunk line to the south. McLane Street Approximately 1,300 lf of 12-inch collection line is needed along McLane Street between 19 th Ave and Orr Way. Newhall Street Approximately 1,300 lf of 8-inch collection line is needed along Newhall Street between 19 th Ave and Orr Way. Orr Way An 10-inch and 12-inch diameter wastewater line is needed to connect the proposed collector lines in McLane St. and Newhall St. to the collector line in Rupert Street. Approximately 800 ft of pipeline will be needed. North Indian Avenue On the north side of the I-10 Freeway, a collector line is needed in Indian Ave. between 19th Ave. and the proposed 20th Ave. Trunk line. About 1,400 ft of 8-inch diameter pipe is needed for this connection. South Indian Avenue Collector Due to the topography south of the I-10 Freeway along Indian Avenue, properties south of Garnet Ave. will not flow to the north by gravity and will therefore require a lift station. Industrial Complex Collector East of Indian Avenue and north of 20 th Avenue there are existing and proposed developments along an unnamed street. A proposed 8-inch diameter collector approximately 2,100 ft long is proposed along this street to convey wastewater generated in this area to the western portion of the proposed 20 th Avenue Trunk line. Due to low flows generated within the complex, the velocity in the 8-inch diameter sewer will be less than 2.0 ft/s. Right-of-Way and Easements The proposed pipeline alignments will be within existing street right-of-way. However, the proposed jack and bore under Interstate 10 from the 20 th Avenue Trunk to the Garnet Avenue Trunk will require an encroachment permit from Caltrans. Discussions between MSWD staff and Caltrans are underway to establish an agreement between the two entities. 4-8

18 Mission Springs Water District Section 5 I-10 & Indian Area Sewer System DR Conclusions and Recommendations SECTION 5 Conclusions and Recommendations The project study area is generally bounded by 18th Ave. to the north, Little Morongo Road to the east, the railroad right of way to the south, and Karen Ave to the west. The natural topography slopes down from the north to the south except for the south east corner of the study area which has rolling hills. Outside of the study boundary to the west and north are wind farms and are not anticipated to generate wastewater tributary to the study area. South of the study boundary and the rolling hills within the boundary are within the Coachella Valley Multiple Species Habitat Conservation which at this time is not developable. Further north of the wind farms are planned residential developments that will generate wastewater. Wastewater generated in this region will contribute to the wastewater flow in the proposed 19 th Ave. trunk line at the Indian Avenue intersection. Average Day and eak Sewer Flows Existing average day flows were based on average annual water meter data provided by the MSWD. It was assumed that 80% of the water will return to the sewer system. For ultimate conditions, average daily flows were based on developer estimates where available and landuse data for all other areas. Existing and ultimate average day flow estimates are provided below. For a detailed breakdown of the estimated flow per development area, refer to the tables provided in Appendix A. Estimated Flows Estimated Flows Gallons per Day Existing 48,122 Ultimate 1,583,680 eak flows are based on MSWD s peaking factors. Average day flows are multiplied by peak factors to obtain estimated peak flows. eak flows were used in this report to determine the minimum allowable pipe diameter size for each segment base on the design criteria discussed herein. These minimum pipe diameter sizes are shown on late 2. roposed Facilities A digital model of two (2) alternative wastewater conveyance systems, identified as Alternative 1 and Alternative 2, were prepared by Webb Associates using SewerCAD. The modeling software has the capabilities to calculate a preliminary design for proposed sewer lines based on the design constraints adopted by MSWD. This design feature was utilized to determine the proposed pipe sizes for the two (2) alternative conveyance systems. These minimum pipe diameter sizes for Alternative 1 and Alternative 2 are shown on late 2 and late 3, respectively. Alternative 1 19 th Avenue Trunk Line This proposed 19 th Avenue trunk line will commence near the intersection of Halleck Rd. and 19th Ave and continue east along 19th Ave. to the proposed RWWT just west of Little Morongo Rd. The pipe diameter will range between 8 to 24 inches and span approximately 9,300 linear feet. The portion of the 19 th Avenue Trunk line east of Indian Avenue (5,300 LF) will primarily be utilized to convey 5-1

19 Mission Springs Water District Section 5 I-10 & Indian Area Sewer System DR Conclusions and Recommendations wastewater generated north of the study area to the RWWT, costs associated with oversizing of this portion of the trunk line are estimated at $260, th Avenue Trunk Line and Sewage Lift Station The 20 th Avenue Trunk line is proposed between Karen Ave. and will terminate just west of Indian Avenue where a sewage lift station will be required to pump flow under the recently completed Indian Avenue I-10 overpass, across Indian Avenue. Otherwise the trunk line would need to be installed at a depth of approximately feet below ground surface and would require that the recently completed bridge improvements be disturbed. East of Indian Avenue, the force main from the sewage lift station will terminate and the 20 th Avenue Trunk line will continue to Little Morongo Road. The 20 th Avenue Trunk line will range in size between 8 to 21 inches in diameter as the projected flows increase from west to east. This line will be approximately 11,000 feet in length and will terminate at a proposed lift station (proposed under another project) near the intersection of 20 th Ave. and Little Morongo Road. Flow variations between existing to ultimate flow conditions are significant for this project and specifically in the area of the proposed lift station. Existing and ultimate peak flow conditions are summarized below. eak Flow Conditions for Sewage Lift Station (Alternative 1) Flow Condition Situation Flow Condition 1 Existing eak Flows 20 gpm Condition 2 Ultimate eak Flows 700 gpm Two (2) options for the proposed lift station were discussed herein, Webb recommends Option 2 to the District which consists of equipping the lift station with three (3) VFD pumping units (each 400 gpm) and the wet well will be sized for an intermediate flow condition, thus reducing its size. The proposed discharge forcemain will be an 8-inch diameter pipe and the wet well will be an 8-foot diameter manhole with a 5-foot working control band which will provide for a pump station operation less than 6 cycles per hour under all flow conditions through 700 gpm. Garnet Avenue Trunk Line The Garnet Avenue Trunk line is proposed to convey wastewater generated within the study area on the south side of Interstate 10 to the 20 th Avenue Trunk line on the north side of Interstate 10. As shown on late 2, this trunk line commences west of Indian Avenue along Garnet Street and traverses east to an existing 12-inch dia. sewer line under Interstate 10. Based on the as-built drawings, the design capacity for the existing 12-inch dia. Sewer line is 0.81 mgd and the ultimate peak flow for this line under Alternative 1 is 0.5 mgd. This trunk line will range in size from 8-inches to 12-inches in diameter and approximately 6,600 feet long. The sewer model indicates that the velocity in the Garnet Avenue Trunk line will be less than 2.0 ft/s under Alternative 1. Due to the topography south of the I-10 Freeway along Indian Avenue, properties south of Garnet Ave. will not flow to the north by gravity and will therefore require a lift station. 5-2

20 Mission Springs Water District Section 5 I-10 & Indian Area Sewer System DR Conclusions and Recommendations Construction Cost Estimate The preliminary construction cost estimate for the facilities discussed herein for Alternative 1 is provided in Appendix C. The construction cost estimate for Alternative 1 is $9,900,000, including a 10% construction contingency. Alternate pipe material, such as VC, for the sewer lines would result in a cost savings of approximately 4-6%. This is considered a preliminary estimate and may be refined upon completion of final design. Alternative 2 19 th Avenue Trunk Line Wastewater generated north of 19 th Avenue and west of Indian Avenue will be collected and conveyed south to 20 th Avenue, where it will be conveyed under Interstate 10 to the Garnet Avenue Trunk Line. The pipe diameters will range in size from 8 inches to 10 inches and span approximately 2,800 linear feet. Wastewater generated north of 19 th Avenue and east of Indian Avenue will be collected and conveyed to the proposed RWWT by means of the 19th Ave. Trunk. This proposed trunk line will commence near the intersection of Indian Avenue and 19th Ave and continue east along 19th Ave. to the proposed RWWT just west of Little Morongo Rd. The pipe diameter will be 24 inches and span approximately 5,300 linear feet. This portion of the 19 th Avenue Trunk line east of Indian Avenue (5,300 LF) will primarily be utilized to convey wastewater generated north of the study area to the RWWT, costs associated with oversizing of this portion of the trunk line are estimated at $251, th Avenue Trunk Line and Sewage Lift Station A proposed trunk line in 20 th Avenue will be utilized to convey wastewater generated between 19 th Avenue and 20 th Avenue within the study area. Similar to the 19 th Avenue Trunk Line, wastewater generated between 19 th Avenue and 20 th Avenue and west of Indian Avenue will be collected and conveyed south, under Interstate 10 to Garnet Avenue Trunk Line. The western portion of 20 th Avenue Trunk line will range in size between 8 to 15 inches in diameter and will be approximately 4,100 feet in length. The eastern portion of the proposed trunk line in 20 th Avenue will be utilized to convey wastewater generated between 19 th Avenue and 20 th Avenue, and east of Indian Avenue. The eastern portion of the 20 th Avenue Trunk line is proposed between Indian Avenue and the existing 12 inch diameter sewer line under Interstate 10 where a sewage lift station will be required to pump flow to the RWWT. The eastern portion of the 20 th Avenue Trunk line will range in size from 8 to 18 inches in diameter and will be approximately 4,800 feet in length. The sewage lift station for Alternative 2 will be a three (3) pump configuration, three pumping units with each unit sized to pump half the ultimate influent peak design flow of 3.25 MGD (2,300 gpm). Flow variations between existing to ultimate flow conditions are significant for this project and specifically in the area of the proposed lift station. Existing and ultimate peak flow conditions are summarized below. 5-3

21 Mission Springs Water District Section 5 I-10 & Indian Area Sewer System DR Conclusions and Recommendations eak Flow Conditions for Sewage Lift Station (Alternative 2) Flow Condition Situation Flow Condition 1 Existing Influent eak Flows 90 gpm Condition 2 Ultimate Influent eak Flows 2,300 gpm Two (2) options for the proposed lift station were discussed herein, Webb recommends Option 2 to the District which consists of equipping the lift station with three (3) VFD pumping units (each 1,150 gpm) and the wet well will be sized for an intermediate flow condition, thus reducing its size. The proposed discharge forcemain will be a 12-inch diameter pipe and the wet well will be a structurally engineered 40-foot deep concrete structure. Garnet Avenue Trunk Line The Garnet Avenue Trunk line is proposed to convey wastewater generated within the study area from north of Interstate 10 and west of Indian Avenue and on the south side of Interstate 10 to the 20 th Avenue Trunk line on the north side of Interstate 10. A jack and bore under Interstate 10 would be required to convey wastewater from the 20 th Street Trunk line, north of Interstate 10, to the Garnet Street Trunk line. As shown on late 3, this trunk line commences west of Indian Avenue along Garnet Street and traverses east to an existing 12-inch dia. sewer line under Interstate 10. This trunk line will range in size from 8 to 18-inches in diameter and approximately 6,600 feet long. The sewer model indicates that the portion of Garnet Avenue Trunk line upstream of the jack and bore under Interstate 10 will have a velocity of less than 2.0 ft/s under Alternative 2. As indicated previously, the design capacity for the existing 12-inch dia. sewer line is 0.81 mgd and the ultimate peak flow for this line under Alternative 2 is 1.84 mgd; therefore this line will be surcharged once ultimate peak flows exceed 0.8 mgd. Ultimate peak flows will approach 0.81 mgd when there are approximately 1,500 EDUs (300,000 mgd average day flows) existing to the west of Indian Avenue, between Interstate 10 and 18 th Avenue, and the entire area south of Interstate 10 which contributes flow to this portion of the sewer collection system. Flows and EDUs should be monitored by the District to evaluate when the existing 12-inch dia. sewer line is approaching design capacity. Construction Cost Estimate The preliminary construction cost estimate for the facilities discussed herein for Alternative 2 is provided in Appendix C. The construction cost estimate for Alternative 2 is $8,800,000, including a 10% construction contingency. Alternate pipe material, such as VC, for the sewer lines would result in a cost savings of approximately 4-6%. This is considered a preliminary estimate and may be refined upon completion of final design. Alternative Comparison Both Alternatives will require lift stations, Alternative 1 will require two (2) lift stations; a 700 gpm lift station with a wet well depth of approximately 20 feet and a larger lift station that will be constructed with the proposed WWT. Alternative 2 will require a 2,300 gpm lift station with a wet well depth of approximately 40 feet. Alternative 1 will, therefore, have additional Operation and Maintenance costs associated with two (2) lift stations compared to one (1) lift station in Alternative 2. Operation and Maintenance costs are not evaluated in this report. Both Alternatives will require jack and bore construction methods and will require encroachment permits from Caltrans. Alternative 1 will have a jack and bore of approximately 5-4

22 Mission Springs Water District Section 5 I-10 & Indian Area Sewer System DR Conclusions and Recommendations 400 linear feet and the jack and bore for Alternative 2 will be approximately 400 linear feet. Alternative 2 will take wastewater flows from north of Interstate 10 to the south side of Interstate 10 through a new sewer pipe under Interstate 10 and then back to the north side via an existing pipe under Interstate 10. Cleaning velocities for both Alternatives are not met at the upstream ends of some of the proposed lines. ipe diameters would need to be smaller than 8-inch or the sewer lines will need to be much deeper to increase the slopes. Cleaning velocities in the Industrial Complex Collector will be less than 2.0 ft/s under Alternative 1 and 2. Cleaning velocities in the entire length of the Garnet Avenue Trunk line will be less than 2.0 ft/s under Alternative 1 and the portion of the trunk line upstream of the jack and bore under Interstate 10 will be less than 2.0 ft/s under Alternative 2. The existing 12-inch dia. sewer line under Interstate 10 has a design capacity of 0.81 mgd and the ultimate peak flow for this line under Alternative 2 is 1.84 mgd; therefore this line will be surcharged once ultimate peak flows exceed 0.8 mgd. Consideration should be given to upsizing this line once flows increase. Estimated costs associated with the replacement of this existing 12-inch dia. sewer line in the future is estimated at $500,000 (estimated construction cost for present day). As indicated, the construction cost estimates for Alternative 1 and 2 are, $9,900,000 and $8,800,000, respectively. Recommendation Based on discussions with District personnel and the data presented herein, Alternative 2 is the preferred sewer system for the Interstate 10 and Indian Avenue Area. Consideration by the District should be given to the comparison of each alternative prior to making a final decision on which alternative to proceed with. 5-5

23 Appendix A Tributary Areas and Estimated Wastewater Flows

24 Imagery by Digital Globe, March 2010 This map contains Geographic Information owned by the County of Riverside * See Appendix A for tributary area information Tributary Area Map $ ` WWT 58 L.S. WWT T-5 T-6 T-7 T-8 T-9 T-17 T-18 T-2 T-3 T-4 T-11 T-12 T-13 T-14 T-15 T-16 T-1 T-10 Tributary Areas 0 Feet 600 O rojects 1,200 MSWD Facilities Study Area Boundary Legend LATE 1 G:\2011\ \GIS\Tributary_Map.mxd Map revised August 29, 2008.

25 Estimated Wastewater Flows Appendix A Tributary Drainage Area Area (ac) Residential 1 Commercial 2 Industrial 2 roposed Development Area (ac) Approx. Existing Estimated Ultimate (ac) (ac) (ac) Flow 3 (gpd) Flow 4 (gpd) T ,615 T ,000 T ,363 T ,000 T T ,562 T ,024 T ,000 T ,445 T ,438 T ,562 T ,385 T ,769 T ,438 T ,532 T ,987 T ,666 T ,943 T ,962 T T ,423 T T ,916 T ,606 T T T T ,720 T ,683 T ,052 T ,789 1,789 T T T T ,280 7,280 T ,259 1,259 T ,863 T T T ,003 1,003 T ,650 T ,100 T ,000 T T T T T ,100 T T ,254 T T T T T T ,095 T ,600 T ,194 5,194 T ,368 4,368 T R:\WO\2011\ \Calculations\MSWD Meter DataSummary

26 Estimated Wastewater Flows Appendix A Tributary Drainage Area Area (ac) Residential 1 (ac) Commercial 2 (ac) Industrial 2 (ac) roposed Development Area (ac) Approx. Existing Flow 3 (gpd) Estimated Ultimate Flow 4 (gpd) T ,200 1,200 T ,325 3,325 T ,335 6,335 T ,102 1,102 T ,057 T ,676 T ,121 T ,144 T T ,629 T T ,440 T ,807 T ,933 T ,500 T ,080 T ,462 T T ,161 1,161 T ,378 7,378 T ,731 1,731 T ,462 T ,417 T T ,966 Total: 1, ,122 1,583,680 1 Residential wastewater flow calculations were based on a medium density of 5 du/ac and 200 gpd/du 2 Commercial and industrial wastewater flow calculations were based on 2000 gpd/ac 3 Existing wastewater flow calculations were based on a 12 month average of water consumption and a water to sewer return ration of 80%. 4 Wastewater flow calculations for undevloped projects were based on information provided by developers. When no flow information was available assumptions were made based on similar building use type or commercial and industrial land use of 2000 gpd/ac. R:\WO\2011\ \Calculations\MSWD Meter DataSummary

27 Appendix B - Model Outputs

28 NET Imagery by Digital Globe, March 2008 This map contains Geographic Information owned by the County of Riverside GAR AVE MH-19 MH MH '' MH-36 MH '' 12 '' MH '' -56 MH-29 MH '' MH-15 MH '' MH '' MH-45 MH MH-43 MH-42 MH-12 ä ' 12 '' -58 MH ' 15 '' MH T H AVE MH-22 MH R'' R W 8 '' AY O RUERT ST HALLECK RD MH T H AVE MH-20 BLAIR RD 8 - '' 48 MH-38 MH-40 MH ' -8 MH '' 12-6 '' MH-7 MH ' -23 '' 19T H AVE MH-39-5 MH-5 MH '' 1 ALTERNATIVE 1 ROOSED IE DIAMETERS -33 McLA NE ST KAREN DR SEWER MODEL RESULTS -55 NEWHALL ST -37 IN DIAN AVE -57 N INDIAN CANYON DR IN DIAN AVE '' GAR NET MH-25 AVE -3 MH-3 $ ` MH '' -26 MH '' 20T H AVE MH-4 18T H AVE CALLE DE LOS ROMOS 18T H AVE '' -43 ' ' A H D '' -4 2 N T O ä 3 Legend L.S. Feet 600 Force Main Gravity Sewer 1,200 WWT Boundary Lift Station roject Boundary WWT LATE 2 ä 3MH-51 LITTLE MORONGO RD A R E W S R 10 G:\2011\ \GIS\Model Results.mxd Map revised Nov. 23, G '' -61

29 Manhole Model Results Alternative 1 Label Ground Elevation (ft) Hydraulic Grade Line In (ft) Hydraulic Grade Line Out (ft) Total Flow (mgd) Manhole Depth (ft) MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH R:\WO\2011\ \Calculations\MSWD Meter Data

30 Manhole Model Results Alternative 1 Label Ground Elevation (ft) Hydraulic Grade Line In (ft) Hydraulic Grade Line Out (ft) Total Flow (mgd) Manhole Depth (ft) MH MH MH MH MH MH MH R:\WO\2011\ \Calculations\MSWD Meter Data

31 Normal Depth / Rise (d/d) (%) -2 MH MH inch MH MH inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH ,016 8 inch MH MH , inch MH MH , inch MH MH , inch MH MH inch MH O inch MH MH inch MH MH inch MH MH inch MH MH ,172 8 inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH ,491 8 inch MH MH ,707 8 inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch ipe Model Results Alternative 1 Label Upstream Node Upstream Invert Elevation (ft) Downstream Node Downstream Invert Elevation (ft) Constructed Slope (ft/ft) Length (ft) Section Size Total Flow (mgd) Design Capacity (mgd) Excess Design Capacity (mgd) R:\WO\2011\ \Calculations\MSWD Meter Data

32 Normal Depth / Rise (d/d) (%) -50 MH MH inch MH MH inch MH MH inch MH MH ,175 8 inch MH MH inch MH MH ,195 8 inch MH MH inch MH O inch MH MH inch MH O inch ipe Model Results Alternative 1 Label Upstream Node Upstream Invert Elevation (ft) Downstream Node Downstream Invert Elevation (ft) Constructed Slope (ft/ft) Length (ft) Section Size Total Flow (mgd) Design Capacity (mgd) Excess Design Capacity (mgd) R:\WO\2011\ \Calculations\MSWD Meter Data

33 NET Imagery by Digital Globe, March 2008 This map contains Geographic Information owned by the County of Riverside GAR AVE MH MH MH '' MH-20 MH-18 HALLECK RD T H AVE BLAIR RD '' MH-36 MH-16 MH '' MH MH-37 MH T H AVE MH MH-45 MH-23 MH '' MH-38 MH-40 MH '' MH-43 MH-42 MH-12 MH '' MH '' ORR WAY MH-21 McLA NE ST -8 MH MH '' MH-7 19T H AVE ALTERNATIVE 2 ROOSED IE DIAMETERS RUERT ST KAREN DR MH '' '' GAR -3 MH '' NET AVE MH-3 $ ` -2 MH-2-26 MH-26 VE 10 '' 10 '' 2 0 T H A MH T H AVE L.S. ä 315 '' MH-5-5 MH-24 SEWER MODEL RESULTS '' NEWHALL ST N INDIAN CANYON DR CALLE DE LOS ROMOS 18T H AVE '' IN DIAN AVE '' 12 ' ' A H D ' -4 ' 2 53 N T 0 O ä 3 Feet 600 1,200 WWT Boundary Lift Station Gravity Line Force Main roject Boundary WWT LATE 3 Legend -2 7 LITTLE MORONGO RD A R E W S R '' G:\2011\ \GIS\Model Results.mxd Map revised Nov. 23, G 8 2 8

34 Manhole Model Results Alternative 2 Label Ground Elevation (ft) Hydraulic Grade Line In (ft) Hydraulic Grade Line Out (ft) Total Flow (mgd) Manhole Depth (ft) MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH R:\WO\2011\ \Calculations\MSWD Meter Data

35 Normal Depth / Rise (d/d) (%) -2 MH MH inch MH MH inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH ,016 8 inch MH MH , inch MH MH , inch MH MH , inch MH MH inch MH O inch MH MH inch MH MH inch MH MH , inch MH MH inch MH MH ,172 8 inch MH MH inch MH MH ,328 8 inch MH MH inch MH MH inch MH MH inch MH MH ,491 8 inch MH MH , inch MH MH , inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH MH inch MH O inch ipe Model Results Alternative 2 Label Upstream Node Upstream Invert Elevation (ft) Downstream Node Downstream Invert Elevation (ft) Constructed Slope (ft/ft) Length (ft) Section Size Total Flow (mgd) Design Capacity (mgd) Excess Design Capacity (mgd) R:\WO\2011\ \Calculations\MSWD Meter Data

36 Appendix C Construction Cost Estimates

37 Mission Springs Water District Alternative 1 - VC Interstate 10 and Indian Avenue Area Sewer June 2012 Construction Cost Estimate reliminary Construction Estimate ITEM QUANTITY DETH (range) UNIT MEAS BID SCHEDULE DESCRITION UNIT RICE TOTAL Interstate 10 and Indian Avenue Area Sewer System LS Mobilization, bonding, insurance & pre-con video $60, $60, Trench & excavation sheeting, shoring & bracing for protection of life & limb per OSHA standard LS $40, $40, <15' LF 24 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $149 $6, ,323 15'-25' $165 $878, >25' $182 $ <15' LF 21 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $135 $ '-25' $150 $97, >25' $165 $ <15' LF 18 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $122 $0.00 1,299 15'-25' $135 $175, ,095 >25' $149 $162, <15' LF 15 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $110 $30, ,013 15'-25' $122 $123, >25' $134 $50, dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A 107 2,960 <15' LF $101 $298, ,932 15'-25' $112 $440, >25' $123 $37, <15' LF 10 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $96 $33, ,520 15'-25' $107 $162, >25' $118 $ ,389 <15' LF 8 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $87 $1,168, ,516 15'-25' $97 $147, >25' $107 $0.00 Furnish and Install 400' (L) x 16 (I.D.) x 1/4 (min. thickness) steel casing but not limited to: backfill & compaction, pavement removal, disposal, replacement, grind & capping, equipment, materials, all per construction drawings & per LF Sewermain Steel Casing Detail, specifications & Caltrans requirements. $ $140, LF 8 dia. VC forcemain $60.00 $54, <15' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $4, $4, '-25' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $7, $315, >25' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $9, $45, <12' EA 4' dia. manholes per MSWD Std. Dwg. No. S-05 $3, $175, LS othole existing utilities prior to any construction $30, $30, LS Air testing & flushing of sewer gravity main $25, $25, avement removal, disposal & replacement, per plans & specifications per County of Riverside requirements (for pipe ,550 LF <15' in depth) $30.00 $496, Complete pavement removal, disposal & replacement, per plans & specifications per County of Riverside requirements 117 8,663 LF (for pipe >15' in depth) $60.00 $519, Grind & asphalt concrete cap per plans & specifications & City of Desert Hot Springs/alm Springs requirements ,213 LF $20.00 $504, gpm (10 hp) Lift Station including all civil, mechanical, and electrical work LS $650, $650, ,300 gpm (40 hp) Lift Station including all civil, mechanical, and electrical work necessary at the WWT LS $1,700, $1,700, ,500 LF 12 dia. VC forcemain $75.00 $187, NDES/SW compliance; provide, obtain approval & implement Storm Water ollution revention lans & Monitoring LS rogram $12, $12, Traffic Control & safety, temporary & final striping of roadways including providing traffic control for surveying & LS inspection activities $65, $65, LS rovide video inspection of constructed pipelines per specifications $20, $20, EA Unknown mainline utility crossings $1, $7, rovide Record Drawing in accordance with the specification LS $1, $1, LS Force Account Work $40, $40, Remove & replace existing traffic loops disturbed during construction, provide for fully functional system & provide for LS temporary traffic detection at signalized during construction intersection $5, $5, Work as specified in the Contract Documents & as shown on drawings not specifically listed in any other bid item 101 thru LS 128 $15, $15, % Construciton Contingency $892, Total Bid $9,900, Const ruct ion Est imat e Alt 1 vcp age 1 ML

38 Mission Springs Water District Alternative 2 - VC Interstate 10 and Indian Avenue Area Sewer June 2012 Construction Cost Estimate reliminary Construction Estimate ITEM QUANTITY DETH (range) UNIT MEAS BID SCHEDULE DESCRITION UNIT RICE TOTAL Interstate 10 and Indian Avenue Area Sewer System LS Mobilization, bonding, insurance & pre-con video $60, $60, Trench & excavation sheeting, shoring & bracing for protection of life & limb per OSHA standard LS $40, $40, ,060 <15' LF 21 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $135 $413, ,204 15'-25' $150 $330, >25' $165 $ <15' LF 18 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $122 $11, ,144 15'-25' $135 $289, >25' $149 $ ,138 <15' LF 15 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $110 $124, ,594 15'-25' $122 $194, >25' $134 $59, dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A 106 2,510 <15' LF $101 $253, '-25' $112 $20, >25' $123 $18, ,895 <15' LF 10 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $96 $278, ,470 15'-25' $107 $157, >25' $118 $ ,784 <15' LF 8 dia. VC sewer main with trench bedding per MSWD Std. Dwg. No. S-01/02A $87 $1,290, '-25' $97 $32, >25' $107 $16, Furnish and Install 400' (L) x 30 (I.D.) x 1/4 (min. thickness) steel casing but not limited to: backfill & compaction, pavement removal, disposal, replacement, grind & capping, equipment, materials, all per construction drawings & per LF Sewermain Steel Casing Detail, specifications & Caltrans requirements. $ $200, ,000 LF 12 dia. VC forcemain $75.00 $375, <15' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $4, $40, '-25' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $7, $175, >25' EA 5' dia. manholes per MSWD Std. Dwg. No. S-06 $9, $27, <12' EA 4' dia. manholes per MSWD Std. Dwg. No. S-05 $3, $227, othole existing utilities prior to any construction LS $30, $30, Air testing & flushing of sewer gravity main LS $25, $25, avement removal, disposal & replacement, per plans & specifications per County of Riverside requirements (for pipe ,079 LF <15' in depth) $30.00 $662, Complete pavement removal, disposal & replacement, per plans & specifications per County of Riverside requirements 117 4,086 LF (for pipe >15' in depth) $60.00 $245, Grind & asphalt concrete cap per plans & specifications & City of Desert Hot Springs/alm Springs requirements ,165 LF $20.00 $523, ,300 gpm (40 hp) Lift Station including all civil, mechanical, and electrical work LS $1,700, $1,700, NDES/SW compliance; provide, obtain approval & implement Storm Water ollution revention lans & Monitoring LS rogram $12, $12, Traffic Control & safety, temporary & final striping of roadways including providing traffic control for surveying & LS inspection activities $65, $65, rovide video inspection of constructed pipelines per specifications LS $20, $20, Unknown mainline utility crossings EA $1, $7, rovide Record Drawing in accordance with the specification LS $1, $1, LS Force Account Work $40, $40, Remove & replace existing traffic loops disturbed during construction, provide for fully functional system & provide for LS temporary traffic detection at signalized during construction intersection $5, $5, Work as specified in the Contract Documents & as shown on drawings not specifically listed in any other bid item 101 thru LS 126 $15, $15, % Construciton Contingency $798, Total Bid $8,800, Const ruct ion Est imat e Alt 2 vcp age 1 ML

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