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SMB Environmental, Inc. P.O. Box 381 Roseville, CA 95661

916-517-2189

Technical Memorandum Date: May 12, 2015 To: Cedric Irving, Environmental Scientist

Ahmad Kaskoli, Senior Environmental Scientist State Water Resources Control Board From: Steve Brown, Principal SMB Environmental, Inc. Daniel Shoup, Professional Archeologist - Archaeological/Historical Consultants Steve Kirkpatrick, City Engineer City of Pleasanton, CA Subject: Section 106 Cultural Resource Issues with City of Pleasantons Recycled Water Project This Technical Memorandum provides an update to the June 2014 Section 106 Cultural Resources Investigation Report and the February 2015 Update Section 106 Cultural Resources Investigation Report that was prepared by SMB Environmental, Inc. (SMB) for the City of Pleasantons (City) Recycled Water Project (Proposed Project/Action). The February 2015 Update Section 106 Cultural Resources Investigation Report was intended to address potential adverse effects on cultural resource areas known as P-01-000066 ( CA-ALA-46) and P-01-000139 (CA-ALA-413), which are of special concern to the Office of Historic Preservation (OHP). The purpose of this Technical Memorandum is to further demonstrate that the Citys Proposed Project/Action will have No Effect to Historic Resources on areas CA-ALA-46 and CA-ALA-413. Please note that this report contains sensitive data that should not be distributed to the public. Archaeological site information is exempted from public disclosure under California Government Code 6245 & 6254.10. This report may be provided to those with a genuine need to know (e.g., regulatory agencies, architects, etc.). Other distribution is not authorized.

PROJECT DESCRIPTION SUMMARY In summary, the City proposes to install pipelines for the distribution of recycled water throughout the City of Pleasanton. As discussed in the Proposed Project/Action Description and Area of Potential Effect (APE) in the original document(s) mentioned above, the proposed construction would basically include approximately 22-miles (115,200 linear feet) of pipeline ranging inform 6-inches to 18-inches in diameter and would be placed primarily within existing paved roadways throughout the City. In addition, the Proposed Action would also include 3.2 miles (16,500 linear feet) of existing pipeline that

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will be repurposed from abandoned or existing potable pipelines. The construction techniques would be primarily using open-cut trenches approximately 3- feet wide and 6- feet deep. Further and as described above, all creek and/or drainage crossings would be constructed using trenchless construction techniques.

EVIDENCE AND RATIONALE SUPPORTING THE NO EFFECT TO HISTORIC RESCOURCES POSITION As part of the Section 106 cultural resources investigation process, a records search was conducted through the Northwest Information Center (NWIC) at Sonoma State University. On May 5, 2014, NWIC issued NWIC File #: 13-1672, which identified five known cultural resources within the Proposed Action alignment, including two prehistoric sites, two historic canals, and a historic railroad alignment. In addition, 41 prior cultural resources studies have covered approximately 75% of the Proposed Action alignment. Of particular concern to the OHP is the Citys Proposed Projects ability to adversely affect CA-ALA-46 and CA-ALA-413. Each is discussed separately below. CA-ALA-46 What follows is a discussion of the relevant background information, rationale and evidence supporting the No Effect to Historic Resources position, and the conclusion for the cultural resources identified as CA-ALA-46. RELEVANT BACKGROUND INFORMATION FOR CA-ALA-46 As shown in Attachment 1, CA-ALA-46 is a prehistoric site, which is located on NWIC maps approximately 100-feet east of the Proposed Project/Actions alignment within the south side of Stoneridge Drive. Previous trenching in 1991 identified it as a buried and disturbed site consisting of one pre-historic Native American burial, one funeral bone tool, fauna, and fire-cracked rock. According to the site record, the resource is located 20-feet south of the intersection of Point Way and Glenn Isle Avenue on the western edge of parcel A, along the western side of Glen Isle Avenue in Tract 6164 of the Stoneridge Place Development. As defined, the CA-ALA-46 has a horizontal buffer of 100-feet from the Proposed Project/Actions pipeline alignment. Further, the size of the site is approximately 67.2 meters (north to south) by 0.6 meters (east to west). The surface elevation of the site is 344 above mean sea level and the resource is buried 150 centimeters or approximately 5-feet below. Figure 2 in the February 2015 Update Section 106 Cultural Resources Investigation Report provides the best estimated location of CA-ALA-46 based on these records and field surveys conducted most recently on January 27, 2015 by Dan Shoup, a professional archeologist assigned to this project. Figure 2 is also provided for your reference in Attachment 2 of this Technical Memorandum. Summarized below is the relevant background information. THERE WILL BE NO EXCAVATION WITHIN THE AREA DELINEATED BY CA-ALA-46 Previous trenching in 1991 identified CA-ALA-46 as a buried and disturbed site consisting of one pre-historic Native American burial, one funeral bone tool, fauna, and fire-cracked rock. According to the site record, the resource is located 20-feet south of the intersection of Point Way and Glenn Isle Avenue on the western edge of Parcel A, along the western side of Glen Isle Avenue in Tract 6164 of the

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Stoneridge Place Development. Furthermore, the size of the site is approximately 67.2 meters (north to south) x 0.6 meters (east to west). The surface elevation of the site is 344 above mean sea level and the resource is buried 150-centimeters or approximately 5-feet below. With this placement, the proposed project is located approximately 100 feet from the known location of CA-ALA-46 as identified by NWIC. Additionally, Attachment 4 provides the drawings for Stoneridge Tract 6164. Of particular note, the drawing referenced as Sheet 8 of those drawings shows the centerline grade of Stoneridge Drive at Stone Pointe/Newton intersection to be at elevation 347 and placed on 6-feet of fill material. As a result, there is an 8- to 11-foot vertical buffer from the Stoneridge Drive road surface and the top of the cultural deposit. With the Proposed Project/Action extending to a depth of 3- to 6-feet, there is a sufficient vertical buffer to avoid impact to the prehistoric site of CA-ALA-46. In summary, the planned trenching for the Citys Recycled Water Pipeline will be located outside the site boundary as identified by NWIC in NWIC File #: 13-1672 as CA-ALA-46 (Attachment 1). CONCLUSION FOR CA-ALA-46 The Proposed Project/Action will have No Effect on the resource known as CA-ALA-46 and no excavation will occur within the area identified by NWIC as CA-ALA-46. There is approximately a 100-foot horizontal buffer from the Proposed Project/Actions alignment in Stoneridge Drive to the CA-ALA-46 site boundary as identified by NWIC. Further, there is an 8-11-foot vertical buffer from CA-ALA-46 and the top of Stoneridge Drive. Given that the Proposed Project/Action would be constructed at a depth of 3-6 feet, there is a sufficient vertical buffer to avoid intersecting the known depth of CA-ALA-46. In short, the Proposed Project/Action will avoid intersecting both horizontally and vertically with CA-ALA-46, thus resulting in no impacts to the cultural resource. CA-ALA-413 What follows is a discussion of the relevant background information, rationale and evidence supporting the No Effect to Historic Resources position, and the conclusion for the cultural resources identified as CA-ALA-413. Based on this information, the Section 106 investigations, as identified above, recommended a series of mitigation measures and concluded that with the implementation of those mitigation measures, that the Citys Proposed Project/Action would have No Effect on this resource and cultural resources throughout the Propose Project/Actions APE. However, the OHP requested additional efforts to clarify and justify the No Effect conclusion on CA-ALA-413. What follows is the result of these additional efforts, which included going through the As-Built Drawings of the New West Positas Boulevard and other constructed projects in the APE from the Citys archives. RELEVANT BACKGROUND INFORMATION FOR CA-ALA-413 As shown in Attachment 3, CA-ALA-413 is a prehistoric mound site that was identified as being located on the western side of the intersection of Las Positas Road and the Iron Horse Trail (formerly the Southern Pacific Railroad). It is important to point out that Las Positas Road is now known as Ithica Way on Google maps and was never extended and is not the same road as the New West Las Positas Boulevard that was built in 1982. It was re-routed in order to by-pass CA-ALA-413 as part of the Hacienda Business Park development. Also adding to some confusion is that Las Positas Road is sometimes referred to as Las Positas Boulevard and/or West Las Positas Boulevard in several of the documents contained within this report. For simplicity, we are referring to the Las Positas Road (now Ithica Way) as the Original Las Positas Road and

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the existing Wet Las Positas Road as the New West Las Positas Boulevard. Previous trenching for a water pipeline in 1978 uncovered a midden site 100 meters (m) in length, buried under 50-100 centimeters (cm) of alluvium, and extending to 270-cm below ground surface. Over 30 human burials were also discovered. THERE WILL BE NO EXCAVATION WITHIN THE AREA DELINEATED BY CA-ALA-413 Further research has revealed that the New Las Positas Boulevard is north and completely outside of CA-ALA-413. NWIC File # 13-1672 was prepared in 1978 as a result of CA-ALA-413 being discovered while a water agency was excavating for a new water line on the west side of Southern Pacific Railroad right-of-way which is now the Iron Horse Trail. The excavation was parallel to the tracks. Site Record CA-ALA-413 includes two maps that delineate the CA-ALA-413 area. The map also shows that the Original Las Positas Road to dead-end on the east side of the Southern Pacific Railroad tracks. In this site record, it does appear and implies that if the Original West Las Positas Boulevard was extended west over the Southern Pacific Railroad tracks it would have crossed the delineated area known as CA-ALA-413. However, it was not extended and this subsequent and more detailed research reveals that the street shown as Las Positas Road in the 1978 site record was never extended to the west through the CA-ALA-413 area. Instead, what was Las Positas Road in 1978 remained a dead end street and is now referred to as Ithica Way on Google Maps. An entire New West Las Positas Boulevard was constructed in 1982 to the north of the Original Las Positas Road and does not enter and completely avoids the horizontal boundary of the CA-ALA-413 delineated area by approximately 70-feet. The following discussion and referenced/attached construction drawings for the Original Las Positas Road and the New West Las Positas Boulevard illustrate these findings:

Attachments 5 and 6 - The 1971 improvement plans for Subdivision Map 3232 and 3290 titled, Las Positas Unit 1 and Las Positas Unit 2. This development is east of the Southern Pacific Railroad right-of-way, and south of the New West Las Positas Boulevard. These plans show the construction of a portion of the Original West Las Positas Boulevard between Santa Rita Road and the east side of the Southern Pacific right-of-way. This is the roadway that is shown on the 1978 NWIC Site Record P-01-000139 (CA-ALA-413) as Las Positas Road. These plans show that the Original West Las Positas Boulevard (i.e. Las Positas Road now Ithica Way) at this time was 20-feet wide and constructed on fill soil varying in depth from 4- to 6-feet.

Attachment 7 - These June 1982 plans prepared by Bissell and Karn for the North Pleasanton

Improvement District show the construction of the New West Las Positas Boulevard between Santa Rita Road and the Southern Pacific right-of-way. These plans also show that the New West Las Positas Boulevard was constructed parallel to and north of the 20-foot wide Original Las Positas Road that was constructed in 1971. These plans show there is approximately 25-feet of landscaped area between the Original Los Positas Road and the New West Las Positas Boulevard, and includes the construction of a sound wall in this area. They also show installation of a cul-de-sac at the west end of the Original 1971 Las Positas Road, with this Original Las Postias Road then only serving the development that was constructed south of it in 1971. The New West Las Positas Boulevard is 88-feet wide and includes a 10-foot wide median, fill material varying in thickness from approximately 4-feet at Santa Rita Road, and 10-feet at the Southern Pacific Right-of-Way. This New West Las Positas Boulevard is the street

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that is in use today and will be the roadway in which the Citys proposed Recycled Water Project would be placed.

Attachment 8 - These February 1982 plans, prepared by Bissell and Karn, are for Parcel Map

3858 titled, Hacienda Business Park. These plans are for the development of the entire Hacienda Business Park (HBP) area, which includes the construction of the New West Las Positas Boulevard west of the Southern Pacific Railroad right-of-way. Before the development of the HBP the area west of the Southern Pacific Railroad right-of-way were farm fields. Sheet 9 of the HBP plans show the New West Las Positas Boulevard from Stoneridge Drive east to the Southern Pacific right-of-way. The plan view at the top of Sheet 9 shows the street width to be 88-feet curb to curb, with a 10-foot wide landscape median matching the dimensions shown in Attachment 7. The profile view at the bottom of Sheet 9 shows the New West Las Positas Boulevard to be constructed on more than 10-feet of fill at the Southern Pacific Railroad right-of-way, with the fill thickness decreasing to the native grade approximately 750-feet west of the Southern Pacific Railroad right-of-way. Page 39 of the 1982 HBP plans identifies the CA-ALA-413 area that was mapped in 1978. As shown on Sheet 39, CA-ALA-413 is located within the triangular property south of the New West Las Positas Boulevard. Next to the area shown on Sheet 39, there is a note that no excavation will be allowed in this area. Please compare Sheet 39 to CA-ALA-413 site records and maps provided in Attachment 3. Sheet 39 also shows the whole triangular area is to receive fill material sloping up toward the railroad right of way, just as is shown on the profile view of the roadway on Sheet 9. This grading in affect protected the CA-ALA-413 area by burying it under 10-feet of fill material. In addition, Steve Kirkpatrick, City Engineer, had a personal communication with Michael Cooper (925-245-8788) on April 21, 2015. Michael Cooper was an engineer at Bissell and Karn who prepared the 1982 plans for the Hacienda Business Park. His initials are on each page of the HBP as-built drawings in the checked by box. Michael Cooper confirmed that the New West Las Positas Boulevard as shown on the plans was located to avoid the prehistoric midden (CA-ALA-413) found in 1978.

Attachment 9 shows Sheet 9 of the February 1982 plans for Parcel Map 3858 titled, Hacienda

Business Park with colored hand drawings to clarify the detailed information above more clearly. More importantly, Figure 1 on the next page provides an updated drawing showing the plan and profile of the New West Las Positas Boulevard in relation to CA-ALA-413.

In summary, Attachments 5 through 9, Figure 1, and our summary of that information, demonstrates that the planned trenching for the Citys Recycled Water Pipeline will be outside the CA-ALA-413 site boundary as identified by NWIC in NWIC File #: 13-1672 (Attachment 2). Attachment 10 provides a revised Figure 3 for the location of site CA-ALA-413 in the February 2015 Section 106 Cultural Resources Investigation Report. THE CLOSEST EXCAVATION TO THE AREA DELINEATED BY CA-ALA-413 WILL BE IN FILL MATERIAL The New West Las Positas Boulevard, immediately adjacent to the Southern Pacific Railroad right-of-way, was constructed in 1982 on top of more than 10-feet of fill material. The mid-1800s era railroad line was built on top of a 10-foot berm. The 1978 Site records for CA-ALA-413 indicate that the site was buried under 50- to 10-centimeters of alluvium, which provides an additional 2-3 feet of extra vertical

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Figure 1

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buffer in addition to the 10-feet of fill mentioned above. As a result, CA-ALA-413 would have a vertical buffer of 12- to 13-feet from the top of the New West Las Positas Boulevard. As the proposed construction activities indicated that underground construction trenching would be limited to 3- to 6-feet, the Proposed Project/Action would be entirely within fill and would provide a 7- to 10-foot vertical buffer from CA-ALA-413. The plans for the construction of the New West Las Positas Boulevard in 1982 on both the east and west side the Southern Pacific Railroad right-of-way shows the berm in street centerline profile view (Attachments 7 and 8). As noted earlier, and as also shown on these plans, the fill material that was placed during the construction of the New West Las Positas Boulevard in 1982. This fill material brought the elevation of the new roadway up to the elevation of Southern Pacific Railroad. Additionally, as previously noted, the fill material buried and protected the CA-ALA-413 area that is located in the property south of the New West Las Positas Boulevard. The construction of the Citys proposed recycled water pipeline will be parallel to and approximately 7-feet from the north curb line of the New West Las Positas Boulevard. At the closest location, which is immediately adjacent to the Southern Pacific Railroad right-of-way, the excavation will be approximately 85-feet north of the area delineated by CA-ALA-413. At this location, the excavation for the Citys proposed recycled water pipeline will be completely within the fill material and will not be deep enough to penetrate the native soil depth shown on the HBP improvement plans. As previously noted and shown on the attached plans, the fill on the west side of the Southern Pacific Railroad right-of-way is approximately 10-feet at the Southern Pacific Railroad right-of-way and decreases in thickness until it matches the native ground elevation approximately 750-feet to the west of the Southern Pacific Railroad. Consequently, the Citys proposed recycled water pipeline excavation would be in fill material for approximately 350-feet west of the Southern Pacific Railroad right-of-way before it is deep enough to penetrate the native ground. As shown graphically in Attachment 8, this point of intersecting native ground is a significant distance west and south of the area delineated by CA-ALA-413. THE PROPOSED PIPELINE WILL BE INSTALLED PARALLEL TO MANY OTHER UTILITIES THAT WERE CONSTRUCTED AS PART OF THE 1982 WEST LAS POSITAS BOULEVARD IMPROVEMENTS AT WHICH TIME NO DISCOVERIES WERE REPORTED Attachments 7 and 8 show that when the New West Las Positas Boulevard was constructed in 1982, it also included the construction various buried utilities, including storm drains, water, sewer, gas, and electric utilities and pipelines. These utilities were constructed in fill material and also penetrated the native ground elevation at approximately 350-feet west of the Southern Pacific Railroad right-of-way. However, no discoveries were reported during the construction of these utilities. As described in the Project Description Summary, the proposed recycled water pipeline will be constructed in less than 6-feet of fill and parallel to the existing pipelines and utilities. Therefore, no discoveries or interaction with CA-ALA-413 are expected to occur. CONCLUSION FOR CA-ALA-413 The Proposed Project/Action will have No Effect on the resources known as CA-ALA-413 based on the following reasons.

1. There will be no excavation within the area identified by the NWIC as CA-ALA-413. In short, the NWIC plotted site location was in relation to the Original Las Positas Road that was

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constructed in 1971 and not the New West Las Positas Boulevard that was constructed in 1982. Thus, there has been confusion as to the location of the proposed project in relation to the CA-ALA-413 site boundary. Since, the Proposed Project/Action is located on the north side of the westbound side of the New West Las Positas Boulevard, it is located approximately 70 feet north of the NWIC Plotted site location.

2. The closest excavation to the area delineated by NWIC as CA-ALA-413 will be in approximately

10-feet of new fill material that was placed since the discovery of the delineated area in 1978 in order to provide a buffer from the construction of the New West Las Positas Boulevard, constructed in 1982 as part of the Hacienda Business Park (HBP) Development and was routed to avoid the potential interaction with CA-ALA-413.

3. The proposed recycled water pipeline will be installed parallel to many other utilities which

were constructed as part of the 1982 New West Las Positas Boulevard improvements and the HBP. During the construction of those facilities, no discoveries were reported.

In short, the Proposed Project/Action will avoid intersecting both horizontally and vertically with CA-ALA-413. OVERALL CONCLUSION AND RECOMMENDATIONS Based upon this additional research and evidence, it is our collective opinion that the construction and/or operation of the Citys Proposed Recycled Water Pipeline Project will have No Effect on the cultural resource sites known as CA-ALA-46 and CA-ALA-413. As with all construction projects, the construction of the Proposed Project/Action could inadvertently uncover buried cultural resources (i.e. Historical, archeological, and human remains. To further reduce the potential to adversely affect any of these resources, the following Inadvertent Discovery Plan (Attachment 11) was prepared and should be implemented as necessary to ensure that there are no adverse effects to unidentified cultural resources that may exist in the APE during the construction of the Proposed Project/Action.