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HomeMy WebLinkAboutInventory & Analysis Summary 2025-12-24 44 12 S CORBETT AVE NUE PORTLAN D, OR 97239 50 3.248.1 939 MAIN 86 6.727.0 140 FAX APE XCOS .COM Foothills District Plan Update Foothills District Lake Oswego, Oregon Prepared for: First Forty Feet 812 SW Washington Street, Suite 250 Portland, Oregon 97205 December 24, 2025 Apex Project 25010940 ATTACHMENT 7/PAGE 1 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC i December 24, 2025 Apex Project 25010940 1 GENERAL SITE HISTORY .............................................................................................................................. 1 2 GEOTECHNICAL ............................................................................................................................................ 1 3 ENVIRONMENTAL HMCS ............................................................................................................................ 2 4 NATURAL SYSTEMS ..................................................................................................................................... 2 5 TRAFFIC ......................................................................................................................................................... 3 5.1 Key Findings ................................................................................................................................................................................. 3 6 PUBLIC UTILITIES ......................................................................................................................................... 4 6.1 Storm .............................................................................................................................................................................................. 4 6.2 Water .............................................................................................................................................................................................. 4 6.3 Sanitary .......................................................................................................................................................................................... 5 7 FRANCHISE UTILITIES .................................................................................................................................. 5 7.1 Power .............................................................................................................................................................................................. 5 7.2 Telecommunications ................................................................................................................................................................ 5 7.3 Natural Gas ................................................................................................................................................................................... 6 8 TRYON CREEK WASTEWATER TREATMENT PLANT .................................................................................. 6 8.1 Challenges and Opportunities .............................................................................................................................................. 6 9 FEMA FLOODPLAIN ...................................................................................................................................... 6 9.1 Key Definitions ............................................................................................................................................................................ 6 9.2 Proposed Development and Hydraulic Flood Protection .......................................................................................... 7 9.3 New FEMA Regulatory Process ............................................................................................................................................ 8 10 REFERENCES ................................................................................................................................................. 9 Supporting Data FIGURES Figure 1. District Boundary Figure 2. Existing Storm Water Figure 3. Existing Potable Water Figure 4. Existing Sanitary Sewer Figure 5. Existing Private Utility Figure 6. Existing Tryon Creek WTP Figure 7. Floodplain / Natural Resources ATTACHMENTS Attachment A: Geotechnical Engineering Feasibility Study Attachment B: Environmental HMCS Attachment C: Natural Systems Attachment D: Existing Conditions Traffic Analysis ©2025 Apex Companies, LLC ATTACHMENT 7/PAGE 2 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 1 December 24, 2025 Apex Project 25010940 1 GENERAL SITE HISTORY The Foothills District is a private and publicly owned mixed-use community in Lake Oswego, Clackamas County, Oregon. The Foothills District contains several entities that serve the City of Lake Oswego (City), which include sanitary services with the Tyron Creek Wastewater Treatment Plant, multi-family housing, commercial businesses, a shopping center, recreational park facilities, and freight railroads. The Foothills District has opportunities to provide enhancements and expansion to the existing public and private services in the city. The site is composed of three distinct subdistricts, which include the North District to the north, the Upper Shelf District to the southwest, and the Garden District to the southeast. The Foothills District study area consists of an area totaling roughly 107 acres and is generally bordered by the Willamette River to the east, N State Street to the west, Tryon Creek to the north, and Leonard Street to the south. At 43 acres, the North District equates to most of the planning area, while the Upper Shelf District and Garden District have a total area of 13.2 acres and 28.4 acres, respectively. The 8-acre Oswego Pointe Condominiums site in the center of the Foothills District is not included in the near-term planning area. See Figure 1 for a visual reference to the district boundaries. The planning area currently has existing buildings, industrial equipment, roads, parking lots, various deciduous trees, shrubs, and lawn surfaces. Below is a summary discussion referencing a 2012 study by Williams/Dame & White and the City of Lake Oswego, as well as the latest updated guidance. 2 GEOTECHNICAL Apex has prepared a preliminary Geotechnical Engineering Feasibility Study for the Foothills District study area. The full detailed report, maps, and figures are included as Attachment A. The following is a summary of those findings and how they might influence the Foothills District Master Plan. Based on our literature and document review and experience in the area, redevelopment of the site appears geotechnically feasible. We anticipate shallow spread footings bearing on native medium-stiff to medium- dense soils (or better) may be suitable for supporting structural loads associated with the proposed redevelopment. If liquefaction or cyclic softening are identified as design concerns in localized areas, they may limit or preclude the use of shallow foundations. The site does have several geological hazards to consider and potentially mitigate in certain portions of the study area. These include slope stability, adverse soils, shallow groundwater, and seismic hazards (liquefaction, lateral spreading, earthquake-induced landslides, and ground shaking). • Groundwater: Previous subsurface explorations reviewed during our research indicate that groundwater may be present at depths as shallow as approximately 3 to 10 feet below ground surface (bgs) in some areas of the site. • Liquefaction: Review of these explorations and available well logs suggests that some site soils located below the groundwater table may be susceptible to liquefaction or cyclic softening during a code-level earthquake. • Excavation/Bedrock: Excavation of near-surface soils using conventional equipment is expected to be feasible. However, the depth to bedrock across the site is variable, appearing as shallow as approximately 5 to 10 feet bgs in some areas. Deeper excavations that extend into bedrock, if required, may necessitate heavy-duty excavation equipment, ripping, or blasting. ATTACHMENT 7/PAGE 3 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 2 December 24, 2025 Apex Project 25010940 3 ENVIRONMENTAL HMCS This Environmental Hazardous Materials Corridor Study evaluates potential sources of contamination that could affect the Foothills development. The report summarizes several potential environmental conditions of high concern identified across the site. Such contamination may influence worker safety, property values, and overall project costs. The full detailed report is included in Attachment B. The proposed location of a new wastewater treatment facility has been the site of a previous cleanup of PCBs with contamination left in place, a regional groundwater plume of chlorinated solvents and a former log pond that may contain buried wood waste. The presence of these contaminants could add significant costs to the construction of the wastewater treatment facility associated with disposal of solid waste and vapor mitigation. The central and eastern portions of the site represented by Areas A and D, as shown in Attachment B, are also of concern due to historic and current operations including automotive repair facilities and lumber mills where the likelihood of soil and groundwater contamination being present is high. While historic activities in the southern portion of the project area may have also resulted in releases to soil and groundwater, these are lower priority as those areas feature long-term residential development that is unlikely to change. In addition to onsite sources of contamination, the study identified many properties along the western property along both sides of State Street that have documented releases to soil and groundwater as well as a history of activities commonly associated with environmental releases including dry cleaners, fueling stations, and automotive repair shops. For known and unknown releases associated with these properties, it’s likely that dissolved contaminants could have migrated eastward in shallow groundwater beneath and across the project site, impacting water quality. Although large scale excavation requiring management of soil and groundwater may not be anticipated outside of the planned location of the wastewater treatment plant, the potential for encountering contaminated soil and groundwater is high across the project area and is likely to result in additional costs related to the management of solid waste and to ensure that conditions protect workers and future occupants of the completed facility. 4 NATURAL SYSTEMS A field reconnaissance was conducted by an Apex Project Biologist in early November 2025. The areas of expected change within the Foothills District were inspected for wetlands, waters, and riparian habitat. The full detailed report is included in Attachment C. Tryon Creek is located at the northern end of the study area and crosses in and out of the defined study area. The creek flows into the Willamette River. Tryon Creek is considered a Class II stream by the City, which requires a 25-foot vegetated buffer and a 10-foot construction setback per Lake Oswego Code (LOC) 50.05.010.6.b.ii. The Oregon Department of State Lands (DSL) has designated it an Essential Salmonid Habitat (ESH). The Willamette River borders the Foothills District to the east and has also been designated an ESH by DSL. The Willamette River Greenway Management Overlay District (WRGM) extends 150 feet shoreward from the ordinary low waterline of the Willamette River and to those areas of the river that are within the city limits. Development projects may be subject to the provisions in LOC Article 50.07. ATTACHMENT 7/PAGE 4 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 3 December 24, 2025 Apex Project 25010940 A formal wetland delineation (WD2017-0435) was completed in 2017. The delineation included the area around the wastewater treatment plant. The delineation identified Tryon Creek, the Willamette River, and two wetlands within the study area. Wetland A–Created Detention Pond was identified in the southeastern corner of tax lot 1501. It is a small detention pond that is approximately 1 to 2 feet deep and was artificially created. Wetland B –Created Flats was identified in the southeastern part of tax lot 1300 in the flat grassy area between the wastewater treatment plant and the Willamette River. DSL confirmed that Tryon Creek and the Willamette River were jurisdictional features, but that the two wetlands were artificially created and were not jurisdictional. The 2017 delineation has expired, and a new delineation will need to be provided prior to development. 5 TRAFFIC An Existing Traffic Engineering Analysis has been prepared for the Foothills District study area. The full detailed report, maps, and figures are included in Attachment D. The following is a summary of those initial findings. N State Street (OR43) is a primary north-south route and Oregon Department of Transportation (ODOT) highway that connects Portland, Lake Oswego, and West Linn along the west bank of the Willamette River. In addition to N State Street being classified as a State Highway, through the downtown area of Lake Oswego the corridor has a special classification within the Oregon Highway Plan as a Special Transportation Area (STA), between Terwilliger Boulevard and McVey Avenue. An STA designation prioritizes local access and circulation for businesses, residences, and community activities while accommodating pedestrians, bicycles, and transit. A Avenue is a primary east-west route through downtown Lake Oswego connecting N State Street (OR43) to areas west of downtown, via Country Club Road and Iron Mountain Boulevard. B Avenue is also a primary connection to State Street (OR43) and to the local street network within the downtown area. Terwilliger Boulevard is a primary route between State Street (OR43) and areas north and east of the Tryon Creek Natural Area. All other study roadways are local streets. The signalized intersection at Foothills Road is currently the only vehicular access connection from the Foothills District to N State Street (OR43) and the surrounding transportation network, including downtown Lake Oswego. The traffic study focused on key intersections around the Foothills District area, primarily along N State Street, to help determine existing conditions and provide a way to measure potential impacts and mitigations with various redevelopment strategies within the Foothills District. 5.1 Key Findings Based on evaluation of existing peak hour intersection operations and the most recent five years of collision history, the study area intersections are all functioning acceptably under existing conditions. The collision history shows the highest number of collisions occurring at the State Street / A Avenue intersection and the A Avenue / 1st Street intersection. The study intersections do not experience an abnormal number of crashes within the five-year period evaluated. The City’s TSP identifies roadway and bicycle/pedestrian projects within the study area, including projects designated as part of the 2012 Foothills Framework Plan. All the projects are noted as “unfunded” within ATTACHMENT 7/PAGE 5 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 4 December 24, 2025 Apex Project 25010940 the City’s current Capital Facilities Plan. • Projects listed within the Foothills District will presumably be modified based on recommendations at the conclusion of this current Foothill Master Plan. • The bicycle and pedestrian facilities along State Street (OR43) and connections between the Foothills District and downtown are either nonexistent or in poor condition. The City’s TSP lists projects that would improve these facilities, but most would be very expensive and are not currently funded. 6 PUBLIC UTILITIES 6.1 Storm The slopes within the Foothills District vary between 0.2% and 80%. The western edge of the Foothills District along N State Street contains the highest points on the Site while the center and the east side of the North District have the lowest points on the site. Runoff generally flows west to east toward the Willamette River. Runoff from the North District is captured by inlets and sent north where the runoff outfalls from a 48-inch pipe into Tryon Creek that feeds into the Willamette River. Runoff generated in the Garden District and the Upper Shelf District is captured by inlets and is sent to the east where the runoff outfalls in multiple locations, varying in pipe size between 12 inches and 42 inches, into the Willamette River. Refer to Figure 2 for an illustration of the narrative blow. The North District has a private water quality pond west of the Tryon Creek Wastewater Treatment Plant that is also considered a wetland. Runoff that enters the facility eventually enters the Willamette River. The district will need to incorporate additional stormwater treatment facilities for new development. New stormwater treatment facilities could be placed throughout the district with each development parcel or a more centralized approach could be considered which may constrain locations of buildings, roads, and utility routing depending on the required size for a centralized approach. Two storm systems within the North District are at or above capacity. The private water quality pond has an emergency pump station that is designed to pump water back to Tryon Creek after a flood event. Another critical system within the North District is the 24-inch line between N State Street and Foothills Road. The 24- inch line conveys water upstream from A Avenue, B Avenue, C Avenue, and Iron Mountain Boulevard, totaling about 90 acres of runoff area. The project has an opportunity to reroute storm pipes where the pipe crossing must be upsized to help mitigate future surcharging and flooding. Consider relocating resized storm lines outside of development parcels to increase developable area. 6.2 Water The Foothills District has multiple water connection tie-in points. N State Street contains a 12-inch water main. There are several existing 8-inch water main loops within the North, Garden, and Upper Shelf Districts. A 42- inch transmission line runs on the western edge of the Garden and Upper Shelf Districts. Due to the Foothills District’s low elevation, there is the expectation of adequate water pressure and volumes to serve both potable and fire water needs for the proposed development. New 8-inch, 10-inch, and 12-inch water lines connected to the 12-inch main in N State Street should be looped within the redeveloped Foothills District area, providing redundancy of supply and future flexibility for accessing the water supply. See Figure 3 for a map of the system. The 12-inch main in N State Street is within the City’s 10th Street Pressure Zone, a gravity-fed zone that serves the downtown and Foothills area. Because the Foothills District sits at one of the lowest elevations within this pressure zone, static pressures are naturally higher and generally favorable for supporting both potable water ATTACHMENT 7/PAGE 6 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 5 December 24, 2025 Apex Project 25010940 service and fire flow demands. The City’s Water Master Plan notes that pressure-reducing valves (PRVs) are commonly required in low-elevation areas where pressures would otherwise exceed the preferred operating range; therefore, future design work should v erify whether pressure regulation is needed at specific connection points. The Master Plan does not identify any existing or projected fire-flow or distribution deficiencies within the 10th Street Zone, and the District’s proximity to the City’s major tran smission lines and the planned Portland intertie improvements further reinforce the reliability of water supply to this area. Together, these factors support the expectation that the Foothills District can be adequately served, provided the internal water system is looped and connected as envisioned. 6.3 Sanitary Several of the larger gravity and pressurized sanitary sewer lines serving the Foothills District may be rerouted with construction of the new TCWTP in the North District. See Section 8 for additional information on the TCWTP. Please refer to Figure 4 for an enlarged map of the preliminary design for the new plant location and piping alignments. The Foothills District has two existing lift stations, Station #SPS00003 located in the center of the North District, and Station #SPS00005 located in the northeast of the Garden District. Lift station #SPS00003 (center) will likely require upgrades and potential relocation to accommodate the increase in users and/or to make way for redevelopment. New development near the eastern edge of the Foothills District would also require the utilization of a lift station to convey flows to the new TCWTP. The development and relocation of the TCWTP may necessitate removal of three aboveground sanitary lines in favor of building new underground lines in a new alignment. The existing aboveground pipes are 24 inches, 30 inches, and 36 inches. The new alignment of the three trunk lines underground should be coordinated with the needs of the Foothills District Master Plan for future development flexibility. One 24-inch pipe segment on Foothills Road is forecasted to be over capacity with future development in the City. This 24-inch segment of pipe conveys flows for the southern and western portions of the city, making this line critical for the City. The 2013 Master Plan calls for adding a 24-inch parallel relief pipe at the bottleneck or replacing/relocating the segment with a single 42-inch diameter pipe as part of the Foothills District redevelopment. 7 FRANCHISE UTILITIES 7.1 Power Portland General Electric (PGE) currently provides overhead power, and possibly underground power, to existing buildings throughout the Foothills District. PGE also operates a substation at the northern edge of the Upper Shelf District, which serves both the Foothills District and downtown Lake Oswego and is interconnected to the regional system through 115 kV transmission lines. Recent coordination with PGE staff indicates that they are not aware of any planned upgrades, relocations, or future projects in this area other than the Foothills redevelopment itself. As the project moves into detailed design and electrical load requirements are better defined, the project team will need to work directly with PGE to confirm system capacity, verify service availability, and coordinate the new underground lines, vaults, and associated infrastructure needed to serve the redevelopment. See Figure 5 for a map of the system. 7.2 Telecommunications Apex assumes new cable, phone, and telecommunication facilities will share the underground conduit runs with the PGE power lines. ATTACHMENT 7/PAGE 7 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 6 December 24, 2025 Apex Project 25010940 7.3 Natural Gas NW Natural maintains an existing gas line along N State Street, which is expected to adequately serve the Foothills District with new mainline extensions as redevelopment occurs. In recent coordination, NW Natural staff confirmed that they are not aware of any planned projects, upgrades, or known capacity constraints in the vicinity other than the Foothills redevelopment itself. As the project advances and the development’s gas demand is better defined, the project team will need to work directly with NW Na tural to confirm system capacity, verify service availability, and coordinate the specific mainline extensions and service connections required to support the final design. See Figure 5 for a map of the system. 8 TRYON CREEK WASTEWATER TREATMENT PLANT (TCWTP) 8.1 Challenges and Opportunities The presence of the existing TCWTP poses a challenge in the form of odors and visual appearance to both existing neighbors (Foothills Park, Tryon Cove Park, and Oswego Pointe Condos) and potential future neighbors. The planned relocation of the TCWTP with a more technologically advanced design will help improve the livability of the Foothills District. See Figure 6 for a map of the existing and new planned location. The new plant is expected to be operational by the end of 2029. The new TCWTP design should be closely coordinated with the Foothills Masterplan as there is a unique opportunity for various design elements of the TCWTP to work in harmony with future redevelopment. For example, the new sanitary sewer trunk and pressure mains could be routed in a way that could leave flexibility for future development. 9 FEMA FLOODPLAIN The Foothills District’s industrial area sits partially within a designated flood management area along the Willamette River, which means any construction within that flood management area must meet special design constraints. Portions of this land could be under water during major flood events. Three elevations are considered: the 1% annual occurrence flood or “100-year event” as defined by the Federal Emergency Management Agency (FEMA), the 1996 flood, and 1 foot above the 1996 flood. The “100-year event,” which has a 1% chance of occurring every year, would reach an elevation of about 33.9 feet National Geodetic Vertical Datum (NGVD). In the 1996 flood, water levels rose to 36.2 feet NGVD. Because of this history, the City has defined the Flood Management Area to include both FEMA-mapped flood zones and the areas impacted by the 1996 flood. Certain structures must be constructed a minimum of 1 foot above the Flood Management Area. Other structures may be constructed according to special consideration for the impacts of flooding. See Figure 7 for a map of these areas. In addition to flood concerns, the area includes sensitive natural resources such as Tryon Creek, which requires a 30-foot buffer to protect its ecosystem. These factors influence how land can be developed safely and responsibly. The rest of this section details further discussion on these requirements. 9.1 Key Definitions • Flood Management Area: The areas depicted on the City’s Flood Management Area Maps, Figures 50.05.011-A to 50.05.011-D. (In the event the maps show the same general area, the mapped areas that have the higher mapped flood elevation shall prevail.) The Flood Management Area Map shows: o FEMA Mapped Areas ATTACHMENT 7/PAGE 8 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 7 December 24, 2025 Apex Project 25010940 ▪ The areas of special flood hazard, as identified by the Federal Insurance Administrator in a scientific and engineering report entitled "The Flood Insurance Study for Clackamas County, OR and Incorporated Cities" and dated January 18, 2019 ▪ FIRM, as issued by FEMA at the time of last amendment of the Flood Management Area Map o 1996 Flood Areas ▪ The area inundated during the February 1996 flood along the Willamette River as shown on Figure 50.05.011-D, which is based on the flood elevation data available at the Engineering Department. The 1996 Flood Areas will be used for regulatory purposes, provided that the data is at least as restrictive as the FEMA Mapped Areas. • Base Flood: The flood having 1% chance of being equaled or exceeded in any given year. • Base Flood Elevation (BFE): The elevation to which floodwater is anticipated to rise during the base flood, per FEMA designation. • Riparian Buffer Zone (RBZ): The outer boundary of the RBZ (riparian buffer zone) is measured from the ordinary high water line (OHW) of a fresh waterbody to 170 feet horizontally on each side of the waterbody. • Vegetated Corridor + Construction Setback: The City-mandated 25-foot buffer is the width of the vegetated corridor within the Riparian Protection Zone for Tryon Creek. Additionally, there is a 10- foot construction setback from the vegetated corridor, per LOC 50.05.010.6.b.iv. • Lake Oswego Design Flood Elevation (LODFE): One foot above either the base flood elevation or the 1996 Flood Inundation Areas, whichever is higher. 9.2 Proposed Development and Hydraulic Flood Protection New development needs to be constructed safely above the Flood Management Area. To build at this elevation the development is expected to require significant fill, which could impact the base flood elevation. All new habitable floor elevations in the Foothills District are recommended to be established at 37.2 feet NGVD29 or higher. This elevation is 4.7 feet above the 100-year floodplain elevation (33.9 feet) and 1 foot above the 1996 flood inundation level (36.2 feet). New streets should also be constructed at or above this elevation wherever possible to ensure safe ingress and egress during future flood events and to protect public and private infrastructure from flood damage. While the City has a requirement that requires balanced cut and fill volumes, the redevelopment project may pursue an exception from this requirement assuming a “no rise” in BFE through hydraulic modeling and analysis. A preliminary hydraulic analysis was conducted in accordance with FEMA and City standards in 2012. The 2012 study concluded that the placement of approximately 75,000 cubic yards of fill within the 100 -year floodplain would result in a "no-rise" to the BFE either upstream or downstream of the project reach. Apex recommends that a new no-rise hydraulic study be performed once there is more clarity on the anticipated redevelopment pattern and more is known about how the new TCWTP and enlargement of Foothills Park to the north will be impacting these calculations with the addition of fill and or cut in the flood management area. A future study is likely to find similar results as the 2012 study for a no rise, assuming that the net fill is similar to what was modeled in 2012. A hydraulic flood study was not included in the scope of this current master planning effort. ATTACHMENT 7/PAGE 9 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 8 December 24, 2025 Apex Project 25010940 9.3 New FEMA Regulatory Process As of 2025, there is a new regulatory review process for development projects within a mapped floodplain in Oregon related to biological function impacts. FEMA has given each city in Oregon a menu of regulatory process options from which to choose and commit to. The City has selected the "Permit-by-Permit" option, which allows cities to carry out pre-implementation compliance measures (PICMs) on a singular permit basis. This approach requires each development application to undergo a habitat assessment to demonstrate that the proposed development will result in "no net loss" to biological floodplain functions within the mapped 170-foot RBZ. This is a different assessment than the “no net rise” for hydraulic function. Within the Foothills District, the RBZ covers areas inside and outside of the City’s Flood Management Area. The RBZ is a buffer study area applied to areas adjacent to Tryon Creek and the Willamette River, as shown in Figure 7. ATTACHMENT 7/PAGE 10 OF 19 Foothills District Plan Update First Forty Feet Foothills District Lake Oswego, Oregon Apex Companies, LLC 9 December 24, 2025 Apex Project 25010940 10 REFERENCES Williams/Dame & White and City of Lake Oswego. (2012). Foothills District Framework Plan, City Council Adopted, July 24, 2012. ATTACHMENT 7/PAGE 11 OF 19 Figures Figure 1. District Boundary Figure 2. Existing Storm Water Figure 3. Existing Potable Water Figure 4. Existing Sanitary Sewer Figure 5. Existing Private Utility Figure 6. Existing Tryon Creek WTP Figure 7. Floodplain / Natural Resources ATTACHMENT 7/PAGE 12 OF 19 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ D i s t r i c t . d w g Jo s h P h e l a n 11 / 1 8 / 2 0 2 5 4 : 3 6 : 0 9 P M SCALE DESIGNED: CHECKED: NOVEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN DISTRICT BOUNDARY 25010940 JRP SAS SHEET ID SHEET OF 71 FIGURE 1 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T TYRON CREEK WWTP D AVE C AVE B AVE A AVE FO O T H I L L S R D FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND STUDY AREA BOUNDARY SUB-DISTRICT BOUNDARY Scale 1" = 0 400 800 400' 200 TRYON CREEK ATTACHMENT 7/PAGE 13 OF 19 EL 104 EL 107 EL 51 EL 40 EL 94 EL 106 EL 83 EL 44 EL 28 EL 32 EL 48 EL 28 EL 111 EL 88 EL 71 EL 95 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ S t o r m . d w g Jo s h P h e l a n 11 / 1 8 / 2 0 2 5 4 : 3 7 : 1 3 P M SCALE DESIGNED: CHECKED: NOVEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN EXISTING STORM WATER 25010940 JRP SAS SHEET ID SHEET OF 72 FIGURE 2 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T S W T E R W I L L I G E R B L V D TYRON CREEK WWTP D AVE E AVE C AVE B AVE A AVE FO O T H I L L S R D PUBLIC STORAGE FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND PIPE SIZE 12" PIPE SIZE >12" Scale 1" = 0 400 800 400' 200 TRYON CREEK 24" LINE OVER CAPACITY EXISTING STORM POND EXISTING POND PUMP STATION EXISTING WATER QUALITY POND EXISTING OUTFALL EXISTING OUTFALL FLOW DIRECTION EL 48 EXISTING SPOT ELEVATION ATTACHMENT 7/PAGE 14 OF 19 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ W a t e r . d w g Jo s h P h e l a n 11 / 1 8 / 2 0 2 5 4 : 4 2 : 4 3 P M SCALE DESIGNED: CHECKED: NOVEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN EXISTING POTABLE WATER 25010940 JRP SAS SHEET ID SHEET OF 73 FIGURE 3 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T S W T E R W I L L I G E R B L V D TYRON CREEK WWTP D AVE E AVE C AVE B AVE A AVE FO O T H I L L S R D PUBLIC STORAGE FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND PIPE SIZE 6" PIPE SIZE 8" PIPE SIZE >8" Scale 1" = 0 400 800 400' 200 TRYON CREEK TRANSMISSION LINE, PIPE SIZE 42" ATTACHMENT 7/PAGE 15 OF 19 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ S a n i t a r y . d w g Jo s h P h e l a n 12 / 2 3 / 2 0 2 5 1 1 : 3 4 : 2 2 A M SCALE DESIGNED: CHECKED: DECEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN EXISTING SANITARY SEWER 25010940 JRP SAS SHEET ID SHEET OF 74 FIGURE 4 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T S W T E R W I L L I G E R B L V D TYRON CREEK WTP D AVE E AVE C AVE B AVE A AVE FO O T H I L L S R D PUBLIC STORAGE FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND GRAVITY PIPE SIZE 8" Scale 1" = 0 400 800 400' 200 T R Y O N C R E E K 24" LINE OVER CAPACITY EXISTING LIFT STATION #SPS00005 EXISTING LIFT STATION #SPS00003 GRAVITY PIPE SIZE >8" PRESSURE PIPE ABANDONED PIPE ABOVE GROUND LINES MAY BE MOVED UNDERGROUNDFLOW DIRECTION EXISTING CITY OF PORTLAND LIFT STATION AND ACCESS TO REMAIN WITH NEW TCWTP EXISTING TCWTP TO BE RELOCATED WEST IN THE DISTRICT ATTACHMENT 7/PAGE 16 OF 19 OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OH P OHP OH P OH P OHP OH P OH P OHP OHP OH P L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ D r y . d w g Jo s h P h e l a n 11 / 1 8 / 2 0 2 5 4 : 4 5 : 2 4 P M SCALE DESIGNED: CHECKED: NOVEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN EXISTING PRIVATE UTILITY 25010940 JRP SAS SHEET ID SHEET OF 75 FIGURE 5 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T S W T E R W I L L I G E R B L V D TYRON CREEK WWTP D AVE E AVE C AVE B AVE A AVE FO O T H I L L S R D PUBLIC STORAGE FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND NATURAL GAS LINE OVERHEAD POWER Scale 1" = 0 400 800 400' 200 TRYON CREEK PGE SUBSTATION OHP ATTACHMENT 7/PAGE 17 OF 19 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ W W T P . d w g Jo s h P h e l a n 12 / 2 3 / 2 0 2 5 1 1 : 3 5 : 1 5 A M SCALE DESIGNED: CHECKED: DECEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN EXISTING TYRON CREEK WTP 25010940 JRP SAS SHEET ID SHEET OF 76 FIGURE 6 W I L L A M E T T E R I V E R S W T E R W I L L I G E R B L V D TYRON CREEK WTP N S T A T E S T LEGEND GRAVITY PIPE SIZE 8" Scale 1" = 0 200 400 200' 100 T R Y O N C R E E K GRAVITY PIPE SIZE >8" PRESSURE PIPE ABANDONED PIPE FLOW DIRECTION PUBLIC STORAGE APPROXIMATE LOCATION OF NEW TCWTP ATTACHMENT 7/PAGE 18 OF 19 EL 104 EL 107 EL 51 EL 40 EL 94 EL 106 EL 83 EL 44 EL 28 EL 32 EL 48 EL 28 EL 111 EL 88 EL 71 EL 95 L: \ P r o j e c t s \ _ D V P \ F \ F I R 0 7 4 \ 2 5 0 1 0 9 4 0 \ C i v i l \ C A D \ W o r k i n g \ E x h i b i t s \ 2 5 0 1 0 9 4 0 _ R e p o r t _ F E M A . d w g Ri l e y O ' B o y l e 12 / 1 / 2 0 2 5 3 : 3 9 : 0 9 P M SCALE DESIGNED: CHECKED: DECEMBER 2025 1" = 400' FOOTHILLS MASTER PLAN FLOODPLAIN / NATURAL RESOURCES 25010940 JRP SAS SHEET ID SHEET OF 77 FIGURE 7 LAK E W O O D B A Y WIL L A M E T T E R I V E R N S T A T E S T TYRON CREEK WWTP D AVE C AVE B AVE A AVE FO O T H I L L S R D FOOTHILLS PARK GARDEN DISTRICT UPPER SHELF DISTRICT NORTH DISTRICT OSWEGO POINTE CONDOMINIUMS OSWEGO VILLAGE CENTER OSWEGO POINTE APARTMENTS OSWEGO POINTE OFFICES LEGEND ORDINARY HIGH WATER (ELEV: 21.15')* 170' RIPARIAN BUFFER ZONE (FEMA) Scale 1" = 0 400 800 400' 200 EXISTING OUTFALL EXISTING OUTFALL STUDY AREA 100-YEAR FLOODPLAIN (FEMA) 25' VEGETATED CORRIDOR + 10' CONSTRUCTION SETBACK (LAKE OSWEGO) AREA OF CHANGE PUBLIC STORAGE STUDY AREA EL 44 WILLAMETTE RIVER GREENWAY MANAGEMENT DISTRICT EXISTING SPOT ELEVATION NOTES: *VERTICAL DATUM NGVD29. 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