11- DSL Basin 6 Wetland Impact Approval.pdf

OREGON DEPARTMENT OF STATE LANDS

GENERAL AUTHORIZATION ELIGIBILITY DETERMINATION

DSL File #: 65783-GA County: Columbia Notification Received Date: 09/10/2025

Issue Date: Expiration Date: (cannot be renewed)

Project Information

Responsible Party: City of St Helens

Project Name: City of St. Helens Wastewater Collection System

Project Address, or location description: Port Avenue ROW

Legal Description: T04N, R01W, Section 08AA, Tax Lot(s) ROW

Latitude, Longitude: Start Point 45.80795, -122825794 to End Point: 45.850636, -122.825484

GA Activity Type(s)

Minimal Disturbance within ESH Waterway Habitat Improvement

Over-Water Structures Fill and Removal Wetland Ecosystem Improvement

Temporary Impacts to Wetlands and Waterways Certain Voluntary Habitat Restoration Activities

Waterway Bank Stabilization Using Bioengineering

DSL Eligibilty Determination Details

In-Water Work Period: to and, if applicable, to .

Activity on State-owned Waterway

Short Term Access Agreement attached Proprietary Auth in DSL File #:

Further Action Required by Applicant BEFORE Starting Work

Obtain DSL Proprietary Authorization

Registration Lease/License Other

Contact DSL Proprietary Staff at:

Contact DSL Registration Staff at:

Contact ODFW to determine if you need Oregon Rescue/Salvage Permit:

(Temporary Impacts to Wetlands and Waterways GA only)

Post-Project Report Required from Applicant

Submit post-project report to DSL within 90 days of rectification (see OAR141-089-0715(9)).

(Temporary Impacts to Wetlands and Waterways GA only)

Submit post-project report to OWEB at http://www.oregon.gov/OWEB upon project completion.

(Waterway Habitat Improvement & Wetland Ecosystem Improvement GAs only)

Eligible if the project is constructed as proposed in the application notification received on the date stated above AND if project complies with all attached conditions.

DSL Staff Signature & Date: _____________________________

775 Summer Street, Suite 100, Salem, OR 97301-1279, Phone: 503-986-5200

October 8, 2025

12/31/2027 10/9/2025

General Authorization Conditions

141-089-0650

The following conditions apply to all individual GAs, unless otherwise specified in an individual GA or a notification under OAR 141-089-0640(3)(a):

(1) Copy of Approved Determination for Inspection. A copy of the determination under OAR 141-089-0640(3)(a) must be available at the work site whenever the project is being conducted.

(2) Local Government Approval Required Before Beginning Work. Prior to the start of work, the responsible party must obtain local government land use approval, where applicable.

(3) Lower Willamette River Management Plan (LWRMP or Plan; OAR 141-080) Consistency. For projects within the purview of the LWRMP, the project must comply with the LWRMP without the need for a minor exception, unless preapproved by the Director, or major exception as described in the Plan.

(4) Site Access Required. Employees of the Department and all authorized representatives must be permitted access to the project area at all reasonable times for the purpose of inspecting work performed on the project.

(5) Hazards to Recreation, Navigation, and Fishing. The project must be timed so as not to interfere with or create a hazard to recreational and commercial navigation and fishing.

(6) Work Period in Jurisdictional Areas. Project activities below the ordinary high water line or highest measured tide line must be conducted consistent with “Oregon Guidelines for Timing of In-Water Work to Protect Fish and Wildlife Resources”, Oregon Department of Fish and Wildlife, March 2024, or other recommendations provided by ODFW included in a response to a notification. Project activities are prohibited when fish eggs are present at the project site.

(7) Preconstruction Resource Area Fencing or Flagging. Prior to any site grading, the boundaries of any avoided wetlands, waterways, and riparian areas adjacent to the project site must be surrounded by noticeable construction fencing or flagging. There must be no vegetation removal or heavy equipment within marked areas. The marked areas must be maintained during construction of the project and be removed immediately upon project completion.

(8) Erosion Control Methods. The following erosion control measures must be installed at the project site prior to construction and maintained during and after construction to prevent erosion and minimize movement of soil into waters of this state:

(a) All exposed soils must be stabilized during and after construction in order to prevent erosion and sedimentation;

(b) Filter bags, sediment fences, sediment traps or catch basins, leave strips or berms, or other measures must be used to prevent movement of soil into waterways and wetlands;

(c) To prevent erosion, use of compost berms, impervious materials, or other equally effective methods, must be used to protect soil stockpiled during rain events or when the stockpile site is not moved or reshaped for more than 48 hours;

(d) Unless part of the permanent fill, all construction access points through, and staging areas in, riparian and wetland areas must use removable pads or mats to prevent soil compaction. However, in some wetland areas under dry summer conditions, this requirement may be waived upon approval by the Department. At project completion, disturbed areas with soil exposed by construction activities must be stabilized by mulching and native vegetative plantings/seeding. Sterile grass may be used instead of native vegetation for temporary sediment control if native vegetation is unavailable. If soils are to remain exposed for more than seven days after completion of the permitted work, they must be covered with erosion control pads, mats, or similar erosion control devices until vegetative stabilization is installed;

(e) Where vegetation is used for erosion control on slopes steeper than 2:1, tackified seed mulch must be used so the seed does not wash away before germination and rooting;

(f) Dredged or other excavated material must be placed on upland areas having stable slopes and must be prevented from eroding back into waterways and wetlands;

(g) Erosion control measures must be inspected and maintained as necessary to ensure their continued effectiveness until soils become stabilized; and

(h) All erosion control structures must be removed when the project is complete and soils stabilized and vegetated. If necessary, removal of erosion control structures may be performed after expiration of the approved OAR 141-089-0640(3)(a) determination.

(9) Hazardous, Toxic, and Waste Material Handling. Petroleum products, chemicals, fresh cement, sandblasted material and chipped paint, wood treated with leachable preservatives or other deleterious waste materials must not be allowed to enter waters of this state. Machinery refueling is to occur at least 150 feet from waters of this state and confined in a designated area to prevent spillage into waters of this state. Barges must have a containment system to effectively prevent petroleum products or other deleterious material from entering waters of this state. Project-related spills into waters of this state or onto land with a potential to enter waters of this state must be reported to the Oregon Emergency Response System (OERS) at 1-800-452-0311.

(10) Archaeological Resources. If any archaeological resources, artifacts, or human remains are encountered during construction, all construction activity must immediately cease, and the State Historic Preservation Office must be contacted. The responsible party may be contacted by a Tribal representative if it is determined by an affected Tribe that the project could affect Tribal cultural or archeological resources.

(11) Construction Corridor. There must be no removal of vegetation or heavy equipment operating or traversing outside the designated construction corridor or footprint.

(12) Raising or Redirecting Water. The project must not cause water to rise or be redirected and result in damage to structures or property.

(13) Waste Disposal. Old piling, spoil material, and other waste material discarded by the project must be disposed of in an appropriate disposal facility. There must be no temporary storage of piling, spoils, or other waste material below top of bank, in any wetland, Federal Emergency Management Administration designated floodway, or an area historically subject to landslides. For the purposes of this general condition, “spoil material” means any material displaced by construction (e.g., soil, sand, gravel, etc.)

and is not intended to be re-incorporated into the project.

(14) Operation of Equipment in the Water.

(a) Heavy equipment may be positioned on or traverse the project area below ordinary high water line or highest measured tide line only when the project area is free of flowing or standing water or if the area is isolated from the waterway and aquatic organism salvage is completed. For the purposes of this general condition, “aquatic organism” means all fish species (including lamprey), freshwater mussels, clams, and crayfish; and any other species as may be identified in a Rescue/Salvage Permit.

(b) All machinery operated below ordinary high water line or highest measured tide line must use biodegradable hydraulic fluids, be steam cleaned and inspected for leaks prior to each use, and be diapered to prevent leakage of fuels, oils, or other fluids below ordinary high water line or highest measured tide line. Any equipment found to be leaking fluids must be immediately removed from and kept above the ordinary high water line or highest measured tide line until repaired.

(15) Fish Passage Required. The project must meet ODFW requirements for fish passage, ORS 509.585.

(16) Temporary Ground Disturbances. Unless otherwise approved by the Department, all temporarily disturbed project areas must be returned to original ground contours and seeded upon completion of ground disturbing actions, and planted with woody vegetation, as appropriate, by March of the year following construction completion.

(17) Nonnative Species. The project will not involve the introduction of nonnative plants other than for temporary soil stabilization. Native seed mixes are preferred. When native seed mix is not available, nonnative seed mix that will hold the soil and not persist may be used if certified free of noxious weeds.

(18) Irrigation. Where power and irrigation water can be made available, irrigation must be provided as necessary until vegetation is established. Irrigation structures must be removed when no longer needed. Invasive weed control must additionally be provided until native vegetation is established.

(19) Invasive Species. Persons must control invasive species and comply with Oregon’s weed laws (ORS Chapters 452, 561, and 570).

(20) DSL May Halt or Modify. DSL retains the authority to temporarily halt or modify the project in case of unforeseen damage to natural resources.

Temporary Impacts to Wetlands and Waterways GA

141-089-0700 Temporary Impacts to Wetlands and Waterways – Purpose OAR 141-089-0700 to 141-089-0715 set forth the conditions under which a person may, without an individual removal-fill permit, general removal fill permit, or DEQ remedial action permit waiver from the Department, temporarily fill or remove material in wetlands and waterways.

141-089-0705 Temporary Impacts to Wetlands and Waterways – Eligibility Requirements To be eligible, a project must adhere to the following:

(1) Wetland Conversion. The project must not convert forested or shrub wetlands to a different Cowardin class nor may it convert any wetland class to open water. The project must not permanently convert waters to upland.

(2) Wetland Delineation and Concurrence. For temporary impacts to wetlands, a copy of a valid, Department-approved wetland delineation map and concurrence letter must be provided with the notification pursuant to OAR 141-089-0640, unless otherwise directed by the Department.

141-089-0710 Temporary Impacts to Wetlands and Waterways – Authorized Projects Project activities are limited to the following.

(1) Temporary impact of 0.50 acres or less of nontidal wetlands;

(2) Temporary impact of 0.20 acres or less of tidal wetlands;

(3) Placement and removal of structures necessary to isolate a work area from a waterway and conduct fish and wildlife salvage not to exceed 100 linear feet measured at the longest length of isolated work area below the ordinary high water line; and

(4) The temporary placement of spud piles (i.e., piles driven into the bed of a waterway to provide stability for a floating work platform) during construction activity.

141-089-0715 Temporary Impacts to Wetlands and Waterways – Project-Specific Conditions

(1) Project activities must adhere to the general conditions in OAR 141-089-0650 and the following project-specific conditions:

(2) Temporary waterway structures for work area isolation must be placed to:

(a) Maintain near-normal downstream flow for the duration of placement and return flow to preconstruction conditions at project completion.

(b) Not be channel-spanning, unless otherwise approved by the Department.

(c) Not be eroded by expected high flows for the duration of placement.

(d) Not dewater any wetlands, unless otherwise approved by the Department as an eligible temporary impact.

(e) Provide for fish and wildlife salvage, rescue, and relocation prior to commencement of any in-water work.

(f) An Oregon Rescue/Salvage Permit from ODFW is required to conduct fish and wildlife salvage (OAR 635-412-0035) and additional authorization may be required from the National Marine Fisheries Service (NMFS) or U.S. Fish and Wildlife Service (USFWS) if federal Endangered Species Act (ESA)-listed species will be affected.

(3) Temporary placement of spud piles for construction platform anchoring may only occur where the platform will not be grounded on the bed or banks of the waterway at any time.

(4) Protection of Wetland Ground Surface. Before placing temporary fill in wetlands, fabric must be placed to allow complete removal of all temporary materials from the wetlands. If necessary to assist with removal of the fill, chain link fence or similar material may be placed under the fill. All fabric, fencing and other materials must be completely removed at project completion.

(5) Trenching in Wetlands. If there is trenching or excavation in wetlands, the top layer of soil must be separated from the rest of the excavated material and put back on top when the trench or pit is backfilled. If the native underlying soils are not used as bedding material and a coarser nonnative soil or other material is used, preventative measures such as clay or concrete plugs must be used so that underground hydraulic piping does not dewater the site and adjacent wetlands.

(6) Temporary Impact Rectification. Rectification of temporary impacts includes re-establishment of pre-existing contours and pre-existing vegetation.

(7) Timing of Temporary Wetland Impact Rectification. Notwithstanding the definition of “Temporary Impacts” in OAR 141-085-0510, the reestablishment of preconstruction contours and planting to revegetate temporarily disturbed wetland areas must be completed within 12 months of the initial impacts or before the expiration of the OAR 141-089-0640(3)(a) determination, whichever comes first, unless otherwise approved by the Department. Planting must include species of sufficient number, spacing, and diversity to replace affected aquatic functions.

(8) Timing of Temporary Waterway Impact Rectification. Reestablishment of preconstruction contours and planting to revegetate temporarily disturbed waterway areas must be completed immediately upon project completion or before or expiration of the OAR 141-089-0640(3)(a) determination, whichever comes first, unless otherwise approved by the Department. Planting must include species of sufficient number, spacing, and diversity to replace affected aquatic functions.

(9) Rectification Monitoring Report Required. Unless otherwise directed by the Department, a rectification report demonstrating restoration of predisturbance grades and revegetation must be provided to the Department within 90 days of temporary impacts rectification. The rectification report must include:

(a) Cover sheet including authorization number, responsible party’s name, current contact information, monitoring date, and report submittal date.

(b) A description of any deviation in the temporary impact size or locations as described in the OAR 141-089-0640(3)(a) determination. Any deviations mut be accompanied by a scaled drawing or map that illustrates the deviation area(s).

(c) A description of any deviation to the restoration of preconstruction grades or revegetation.

(d) For temporary wetland impacts: data plots, according to OAR 141-090, to confirm that the wetland area temporarily impacted by the project meets wetland criteria.

(e) Representative photographs (with photo point locations illustrated) clearly showing conditions within the rectification area(s).

12965 SW Herman Road, Suite 100

Tualatin, OR 97062

(503) 563-6151

Wastewater Collection System Capacity Improvements

St. Helens, Columbia County, Oregon Wetlands and Waters Delineation Report

Date: March 2025

Prepared for: City of St. Helens

265 Strand Street St. Helens, OR 97051

Prepared by: AKS Engineering & Forestry, LLC Emma Eichhorn, Natural Resource Specialist Julie Wirth-McGee, Sr Environmental Specialist, PWS

Study Area: Township 04N, Range 01W, Sections 3, 4, 5, 8 and 9

St. Helens, Columbia County, Oregon

AKS Job Number: 10363-04

Table of Contents Introduction A. Landscape Setting and Land Use B. Site Alterations C. Precipitation Data and Analysis D. Site-Specific Methods E. Description of All Wetlands and Other Non-Wetland Waters

Wetlands Wetland A Wetland B Wetland C

Non-Wetland Waters Water 1 Water 2 Water 3

Wetland Waters Water 4

Upland F. Deviation from LWI G. Mapping Method H. Additional Information

DSL Preliminary Jurisdictional Determination USACE Preliminary Jurisdictional Determination

I. Summary of Results and Conclusions J. Required Disclaimer K. List of Preparers Literature Cited and Referenced

Tables Table 1: Summary of Study Results and Conclusions

Appendices Appendix A: Maps

Figure 1 – USGS Vicinity Map Figure 2 – Tax Map Sections Overview Map Wetlands and Waters Delineation Overview Maps A-C Wetland and Waters Delineation Detail Maps 1-4

Appendix B: Wetland Determination Data Forms Appendix C: Representative Site Photographs Appendix D: APT Reports Appendix E: SDAM Data Form Appendix F: List of all tax maps in the study area Appendix F: Literature Cited and Referenced

Wastewater Collection System Capacity Improvements – St. Helens

March 2025

Introduction AKS Engineering & Forestry, LLC (AK) is working with Consor North America, Inc. and the City of St. Helens on the proposed Wastewater Collection System Capacity Improvements project. This report was prepared in accordance with Oregon Administrative Rules (OAR) 141-090-0030 and 141-090-0035 and describes the results of a wetland and waters delineation conducted on portions of rights-of-way and tax lots within Sections 4N1W3, 4N1W4, 4N1W5, 4N1W8, and 4N1W9 in St. Helens, Columbia County, Oregon. A list of Columbia County Tax Assessor’s Maps and Tax Lots within the study area is included as Appendix F. The study area is divided into two wastewater collection drainage basins referred to as Basin 5 and Basin 6.

The study area includes a total of ±18.06 acres and is shown in the figures provided in Appendix A.

AKS conducted site visits on December 12, 2024, and February 10, 2025. The on-site boundary of one Palustrine Forested (PFO)/Palustrine Scrub-Shrub (PSS) wetland (referred to as Wetland A) was delineated under this study in Basin 5. In Basin 6, one PFO wetland (referred to as Wetland B), one Palustrine Emergent (PEM)/PFO wetland (referred to as Wetland C), three intermittent streams (referred to as Waters 1 through 3), and one wetland-water (referred to as Water 4) were delineated.

A. Landscape Setting and Land Use The study area within Basin 5 consists of the Plymouth Street, S Fifth Street, Cowlitz Street, and South Fourth Street rights-of-way. The northern half of Basin 5 extends through a residential neighborhood and consists primarily of improved surfaces and residential lawns and landscaping. The southern half of this basin is mostly unimproved but contains a dirt hiking trail and elevated wooden boardwalk. Vegetation in this area is dominated by a forested canopy of Oregon ash (Fraxinus latifolia; FACW), red alder (Alnus rubra; FAC), and Oregon white oak (Quercus garryana; FACU). The sapling/shrub layer is dominated by Himalayan blackberry (Rubus armeniacus; FAC), common snowberry (Symphoricarpos albus; FACU), red alder, and Oregon ash. The herb stratum is dominated by English ivy (Hedera ivy; FACU), orchard grass (Dactylis glomerata; FACU), and western sword fern (Polystichum munitum, FACU).

The study area within Basin 6 consists of Port Avenue, Lower Columbia River Highway, Sykes Road, and Gable Road, and Kaster Road rights-of-way along with a portion of tax lots immediately west of Port Avenue, and portions of tax lots between Sykes Road and Gable Road. Most of the Basin 6 study area consists of improved surfaces within the rights-of-way. Vegetated areas along Gable and Sykes Roads consist of mowed lawns, weedy herbaceous species, various ornamental trees and shrubs, and scattered Oregon white oaks and Douglas fir (Pseudotsuga menziesii, FACU). In undeveloped portions of Port Avenue, vegetation is dominant in Balsam poplar (Populus balsamifera, FAC), Oregon ash, Oregon white oak, red alder, Bigleaf maple (Acer macrophyllum, FACU), willow species (Salix spp., assumed FACW), Himalayan blackberry, tall false rye grass (Schedonorus arundinaceus, FAC), bentgrass (Agrostis spp., FAC), reed canary grass (Phalaris arundinacea, FACW), and Queen Anne’s lace (Daucus carota, FACU).

Natural Resource Conservation Service (NRCS) mapped soils units within the study area are shown on the Wetlands and Waters Delineation Overview Maps A through C and Wetland and Waters Delineation Detail Maps 1 through 4. The following three soil units are mapped in the study area per the NRCS Columbia County Area Soil Survey Map:

Aloha variant silt loam (Unit 2), 0 to 3 percent slopes; Non-hydric Wollent silt loam (Unit 69) 0 to 3 percent slopes; Hydric

March 2025

Rock outcrop-Xerumbrepts complex, undulating (Unit 45), 0% to 10% slopes; Non-hydric

B. Site Alterations Historical aerial imagery dating from 1990 to 2024 was reviewed to determine if any site alterations may have affected the presence, location, or geographic boundaries of any wetlands or waters within the study area. According to historical aerial imagery, an increase in residential and commercial development was observed in both Basin 5 and Basin 6 beginning in 1995. Historical alterations were observed during the field reconnaissance in an area just south of Water 1 and Water 2 in Tax Lot 800 (Tax Map 40105CD).

Based on our review of aerial imagery, it appears that the landowner piped a previously daylighted channel with an undersized culvert sometime between May and August of 2010. As a result, there has been an increase in impounded water within the channels of Waters 1 and 2 within the study area due to restricted flow, as evidenced by the stagnant/standing water observed during the February 10, 2025 site visit.

C. Precipitation Data and Analysis Fieldwork was conducted on December 12, 2024, and February 10, 2025. Observed precipitation data was obtained from the Scappoose Industrial Airport (AP) station using the Applied Climate Information System (ACIS). According to the Scappoose Industrial AP Climate Analysis for Wetlands Tables (WETS) data, the growing season is between February 1st and December 23rd. As a result, both site visits were conducted during the growing season.

According to the ACIS Scappoose Industrial AP station, 0.07 inches of rainfall were received on the day of the December 12, 2024, site visit and 0.42 inches of rainfall were received during the two weeks prior.

Observed water year to date (starting October 1, 2024) was 11.06 inches, which was 88 percent of normal.

On the day of the February 10, 2025, site visit no rainfall was received and 0.95 inches of rainfall were received during the two weeks prior. Observed water year to date (starting October 1, 2024) was 20.77 inches, which was 82 percent of normal.

Precipitation for the three-month periods leading up to the site visits were analyzed using the US Army Corps of Engineers (USACE) Antecedent Precipitation Tool (APT), Version 1.0.20 (USACE 2022). Based on the APT reports, monthly observed precipitation for the three months preceding both site visits were determined to be normal. Results of the APT analysis for the site visits conducted on December 12, 2024, and February 10, 2025, are included in Appendix D.

D. Site-Specific Methods The methodology used to determine the presence of wetlands followed the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Environmental Laboratory 2010), and the DSL Guidance for Delineations for Large and Linear Projects (January 2017). The National Wetland Plant List (USACE 2022) was used to assign wetland indicator status for the appropriate region. The US Fish & Wildlife Service (USFWS) Cowardin classification system (Cowardin, et al. 1979) was used to describe wetland vegetation communities. The Oregon Department of State Lands (DSL) Guidebook for Hydrogeomorphic (HGM)-based Assessment of Oregon Wetland and Riparian Sites:

Statewide Classification and Profiles (Adamus 2001) was used to assign HGM class.

March 2025

Fieldwork was conducted on December 12, 2024, by AKS Senior Wetland Scientist Julie Wirth-McGee, PWS, and Natural Resource Specialists Emma Eichhorn and Allison Law. A follow-up site visit on February 10, 2025, was conducted by AKS Natural Resource Specialists Emma Eichhorn and Allison Law. Soils, vegetation, and indicators of hydrology were recorded at 23 sample plot locations on standardized wetland determination data forms (Appendix B) to document site conditions.

Plots within Basin 5 were recorded in a topographically low depression in the vicinity of a wetland identified by DSL in 2020 (DSL File Np. WD2020-0009). No NRCS-mapped hydric soils, or National Wetland Inventory (NWI) or Local Wetland Inventory (LWI)-mapped wetlands are present in Basin 5. Two sets of paired plots were established along the to confirm that a change in vegetation and topographic shift was consistent with the wetland-upland interface and the remainder of the Wetland A boundary was delineated along that interface.

Plots within Basin 6 were recorded within NRCS-mapped hydric soils, NWI, and LWI mapped wetlands and waters, and in topographically low areas along the toe of roadway fill prisms. Paired plots were established along the wetland-upland interfaces to delineate the boundaries of Wetlands B and C. One additional plot (Plot 8) was recorded to document wetland conditions within Wetland B. Ten additional standalone plots were recorded to document upland conditions within Basin 6.

The ordinary high water (OHW) of non-wetland waters were delineated based on physical field indicators in accordance with Oregon Administrative Rule (OAR) 141-085-0515(3), including changes in topography, vegetation, and sediment characteristics.

The streamflow duration for Water 3 was determined using the Environmental Protection Agency (EPA) Streamflow Duration Assessment Method for Oregon (SDAM). The SDAM data sheet is included in Appendix E.

E. Description of All Wetlands and Other Non-Wetland Waters One wetland was delineated in Basin 5, and two wetlands, three intermittent streams, and one wetland-water were delineated within Basin 6. The delineated wetlands and waters are shown on the Wetlands and Waters Delineation Overview Maps and Wetlands and Waters Delineation Detail Maps in Appendix A. Representative ground-level site photographs are included in Appendix C.

Wetlands Wetland A Wetland A covers ±0.14 acres in the southern portion of Basin 5. Wetland A consists of two Cowardin classifications. The southern portion of the wetland is classified as PFO wetland dominated by a forested canopy of Oregon ash, a sapling/shrub layer of Himalayan blackberry, and reed canary grass (Phalaris arundinacea; FACW) as documented in Plots 2 and 4. The northern portion of Wetland A is classified as PSS dominant in Douglas’ meadowsweet (Spiraea douglasii, FACW) and reed canary grass as documented in Plot 4. The main hydrology source for Wetland A is direct precipitation and surface runoff from surrounding uplands. Wetland A lacks an outlet channel and/or connection to a permanent river or lake.

Therefore, the HGM classification for Wetland A is Flats. The wetland boundary was delineated based on a distinct change in topography along with a shift in the vegetation community from facultative wet (FACW) species to an upland vegetation community composed primarily of facultative (FAC) species as documented in upland Plots 1 and 3. Wetland A extends outside the study area to the east.

March 2025

Wetland B Wetland B covers ±0.02 acres within the Port Avenue right-of-way and Tax Lot 500 (Tax Map 04 01 09 BO) south of Port Avenue. Wetland B is dominant in willows greater than 3 inches diameter at breast height and reed canary grass as documented in Plots 8, 13, and 16. Therefore, Wetland B is classified as PFO. The primary hydrology source for Wetland B is a seasonally high groundwater table, with lateral subsurface flow and surface runoff providing secondary inputs. As a result, Wetland B belongs to the Slope Valley (SV) HGM class. The wetland boundary was delineated based on a change in landform and vegetation.

Wetland A is within a subtle concave depression dominated in FACW vegetation. The boundary was delineated along a defined toe of a slope in the southern boundary and Port Avenue fill prism along the eastern boundary. Wetland B continues off-site to the southeast and southwest. Trees within Wetland B have an average diameter at breast height (DBH) of less than 18 inches, and according to Google Earth aerial imagery the trees are less than 80 years old. Therefore, the wetland does not meet the DSL’s definition for mature forested wetlands and is not considered an Aquatic Resources of Special Concern

(ARSC).

Wetland C Wetland C is ±0.18 acres and was delineated in the Port Avenue right of way and within a portion of Tax Lot 600 (Tax Map 04 01 08 AA). The vegetation in the eastern portion of Wetland C is dominated by Balsam poplar and reed canary grass; the western portion of Wetland C is dominated by reed canary grass.

Therefore, Wetland C is classified as PEM/PFO/. The primary hydrology source for Wetland C is a seasonally high groundwater table, with lateral subsurface flow and surface runoff providing secondary inputs. As a result, Wetland C belongs to the SV HGM class. Wetland C continues off-site to the south, east and west. The PFO portion of Wetland C contains trees that have an average DBH of less than 18 inches, and according to Google Earth Aerial Imagery the trees are less than 80 years old. Therefore, the wetland does not meet DSL’s definition for mature forested wetlands and is not considered an ARSC.

Non-Wetland Waters Water 1 Water 1 is an intermittent stream located along the south side of Sykes Road that originates northwest of the study area, flowing through a series of daylighted and piped channels prior to being conveyed under Sykes Road into the study area through one 36-inch culvert and one 42-inch culvert. The OHW of Water 1 was delineated based on a distinct break in topography and lack of vegetation below the OHW. Water 1 extends off-site to the south discharging into the North Fork McNulty Creek and ultimately the Columbia River. Water 1 is characterized by a silt channel bed and roughly 1-foot-tall banks that are primarily unvegetated. According to the Oregon Department of Fish and Wildlife (ODFW) Oregon Fish Habitat Distribution and Barriers Map, Water 1 is fish bearing (coastal cutthroat trout), but it is not designated Essential Salmonid Habitat (ESH).

Water 2 Water 2 is located along the south side of Sykes Road, east of Water 1, and is fed only by stormwater runoff collected and conveyed to the outfall from the north and southeast. Because the only hydrology source to Water 2 is stormwater runoff, it is believed to be ephemeral under natural conditions; however, this could not be confirmed due to standing water observed in the channel due to the off-site alterations restricting flow and impounding water in the study area. As a result, Water 2 has been identified as an intermittent water. Surface flows from Water 2 discharge into Water 1. Water 2 is characterized by a silt

March 2025 channel bed and roughly 1-foot-tall banks that are primarily unvegetated. According to the ODFW Oregon Fish Habitat Distribution and Barriers Map, Water 2 is not fish bearing and it is not designated ESH.

Water 3 Water 3 is an intermittent stream located south of Port Avenue adjacent to Wetland B. The hydrology for Water 3 originates from a 16-inch culvert piped under Port Avenue conveying stormwater and potentially overflow water from an artificial pond east of Port Avenue. SDAM results indicated an intermittent flow regime due to the presence of hydrophytic vegetation within one-half channel width. However, because no surface water (flowing or ponding) was observed within Water 3 during either of the site visits, which were conducted during the wet season under normal climatic conditions, it is believed to be ephemeral.

Within the study area, Water 3 is characterized by a gravel channel bed intermixed with sediment and fines, with less than 6-inch tall, unvegetated banks. Water 3 extends off-site to the south and is not mapped as habitat for native migratory fish or designated ESH according to ODFW.

Wetland Waters Water 4 Water 4 originates north of the study area and is fed primarily by stormwater runoff from development north of the Columbia River Highway. The centerline for Water 4 was delineated in Wetland C with an average width of ±3 feet. The channel has a sediment bottom and is vegetated with reed canary grass and contained ±10-12 inches of ponded and flowing water during the February 10, 2025, site visit. Water 4 lacked a defined bed and bank and clearly defined OHW. Due to the presence of surface water, soil samples were not obtained. However, it is anticipated the soil profile would be consistent with the adjacent areas within Wetland C. According to ODFW, Water 4 is mapped as habitat for coastal cutthroat trout. Water 4 is not mapped as Essential Salmonid Habitat (ESH) by ODFW. Water 4 extends outside of the study area to the south, discharging into McNulty Creek and ultimately the Columbia River.

Upland Six standalone sample plots (Plots 5 and 6, and 9 through 12) confirmed upland conditions along the toe of the road fill prism along the southeastern portion of Port Avenue. A standalone plot (Plot 20) was established in 18th Street right-of-way to document upland conditions in the eastern segment of Basin 6.

Within the Sykes Road right-of-way, three standalone sample plots (Plots 21 through 23) were documented in mapped hydric soils. All standalone plots were determined to be upland because they lacked hydric soils. All plots except Plot 9 lacked wetland hydrology. Plots 10 and 11 lacked wetland vegetation.

F. Deviation from LWI The study area is within the DSL-approved Local Wetland Inventory (LWI) for the City of St. Helens. The LWI is shown on the Wetlands and Waters Delineation Overview Maps and Wetland and Waters Delineation Details Maps included in Appendix A. According to the LWI, no wetlands or waters are mapped within Basin 5. AKS delineated Wetland A in Basin 5. In Basin 6, the LWI maps one wetland referred to as MC-08 on the south side of Sykes Road in the vicinity of Waters 1 and 2 delineated by AKS. Additionally, a wetland referred to as MC-22 is mapped in the vicinity of Wetland C and Water 4 delineated by AKS. No wetlands or waters are mapped on the LWI in the vicinity of Wetland B and Water 3 delineated by AKS.

March 2025

G. Mapping Method Wetland boundaries shown were delineated by AKS on December 12, 2024, and February 10, 2025, and mapped with submeter accuracy using a Trimble GEO 7X handheld GPS. The wetland boundaries were flagged with orange wire whips and the sample plots with pink wire whips.

H. Additional Information

DSL Preliminary Jurisdictional Determination Wetlands A, B, and C are naturally occurring wetlands and therefore likely jurisdictional to DSL according to OAR 141-085-0515(4).

Intermittent streams are jurisdictional to DSL to the OHW according to OAR 141-085-0515(3). All waters delineated within the study area determined to be intermittent by AKS and are likely jurisdictional to DSL.

USACE Preliminary Jurisdictional Determination Wetlands A is an isolated wetland without a continuous surface connection to Waters of the United States (WOTUS) according to review of available background mapping (NWI, LWI, National Hydrography Dataset), recent Google Earth aerial imagery, on-site observations, and confirmation of upland conditions surrounding the wetlands. Therefore, Wetland A is likely non-jurisdictional to USACE.

Waters 1 and 2 are relatively permanent waters that extend off-site to the south through a series of ditches to North Fork McNulty Creek. North Fork McNulty Creek drains to McNulty Creek which drains to Scappoose Bay which drains to the Columbia River, a Traditional Navigable Water (TNW). Therefore, Waters 1 and 2 are likely jurisdictional to USACE.

Wetland B is adjacent to Water 3. Although Water 3’s connection to downstream wetlands and/or waters could not be verified, review of Google Earth aerial imagery indicates Water 3 potentially drains to McNulty Creek via LWI-mapped wetlands to the south and a series of unmapped ditches and piped drainages. Therefore, Wetland B and Water 3 may be considered jurisdictional to USACE.

Wetland C and Water 4 extend off-site to the south with a continuous and distinguishable surface connection to McNulty Creek and ultimately the Columbia River, a TNW, according to the NWI and LWI.

Therefore, Wetlands C and Water 4 are likely jurisdictional to USACE.

I. Summary of Results and Conclusions Table 1 on the following page provides a summary of the on-site sizes of the features, hydrologic connections to other nearby waters, the Cowardin and HGM classifications for the wetlands, flow regime of waters, and prediction of whether each feature would likely be determined jurisdictional to DSL and

USACE.

March 2025

Table 1: Summary of Study Results and Conclusions

J. Required Disclaimer This report documents the investigation, BPJ, and conclusions of the investigators. It is correct and complete to the best of our knowledge. It should be considered a Preliminary Jurisdictional Determination of wetlands and other waters and used at your own risk, unless it has been reviewed and approved in writing by the Oregon Department of State Lands in accordance with Oregon Administrative Rules (OAR) 141-090-0005 through 141-090-0055.

K. List of Preparers

Emma Eichhorn Julie Wirth-McGee, PWS Natural Resource Specialist Senior Environmental Specialist Fieldwork and Report Preparation Fieldwork and Report QA/QC

Potentially Jurisdictional

Feature Size Cowardin

Class

HGM

Class/Flow

Regime

Connection to Other Waters

DSL/USACE

Predicted

Jurisdiction

Wetland A ±0.14 acres ±5,912 square feet

PFO/PSS Flats None DSL

Wetland B ±0.02 acres ±810 square feet PFO SV Water 3 DSL/USACE

Wetland C ±0.17 acres ±7,547 square feet PEM/PFO SV McNulty Creek DSL/USACE

Water 1 ±2.5 linear feet/ ±21 square feet

R4SBC Intermittent North Fork McNulty Creek DSL/USACE

Water 2 ±7 linear feet/ ±43 square feet

R4SBC Intermittent Water 1 DSL/USACE

Water 3 ±58.5 linear feet/ ±542 square feet R4SBC Intermittent McNulty Creek DSL/USACE

Water 4 ±108 linear feet R4SBC Intermittent McNulty Creek DSL/USACE

Appendix A: Maps

Appendix B: Wetland Determination Data Forms

Project/Site: Sampling Date:

Applicant/Owner: State: Sampling Point:

Investigator(s): Section, Township, Range:

Landform (hillslope, terrace, etc.): Terrace Local relief (concave, convex, none): Slope (%):

Subregion (LRR): Lat: Long: Datum:

Soil Map Unit Name: NWI classification:

Are climatic / hydrologic conditions on the site typical for this time of year? Yes No (If no, explain in Remarks) Are Vegetation 0 0 , or Hydrology significantly disturbed? Are “Normal Circumstances” present? Yes X No 0 Are Vegetation 0 0 , or Hydrology naturally problematic? (If needed, explain any answers in Remarks.)

SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc.

Hydrophytic Vegetation Present? Yes 0 No X Hydric Soil Present? Yes 0 No X Is the Sampled Area

Wetland Hydrology Present? Yes 0 No X within a Wetland? Yes No

Absolute Dominant Indicator Dominance Test worksheet:

% Cover Species? Status Number of Dominant Species

1. 30% Yes FACU That Are OBL, FACW, or FAC: (A)

2. 0

3. 0 Total Number of Dominant

4. 0 Species Across All Strata: (B)

30% = Total Cover Percent of Dominant Species

1. 35% Yes FAC That Are OBL, FACW, or FAC: (A/B)

2. 10% Yes FAC Prevalence Index worksheet:

3. 0 Total % Cover of: Multiply by:

4. 0 OBL species x 1 =

5. 0 FACW species x 2 =

45% = Total Cover FAC species x 3 =

FACU species x 4 =

1. 50% Yes FACU UPL species x 5 =

2. 0 Column Totals: (A) (B)

3. 0 Prevalence Index = B/A =

4. 0 Hydrophytic Vegetation Indicators:

5. 0 1 - Rapid Test for Hydrophytic Vegetation

6. 0 2 - Dominance Test is >50%

7. 0 3 - Prevalence Index is ≤3.01

8. 0 4 - Morphological Adaptations1 (Provide supporting

9. 0 data in Remarks or on a separate sheet)

10. 0 5 - Wetland Non-Vascular Plants1

11. 0

50% = Total Cover 1Indicators of hydric soil and wetland hydrology must Woody Vine Stratum (Plot Size: 10' r or ______) be present.

1. 0

2. 0 Hydrophytic

0% = Total Cover Vegetation Yes No % Bare Ground in Herb Stratum 50% Present?

City/County:

Julie Wirth-McGee, PWS, Emma Eichhorn, and Allison Law

Precipitation:

Alnus rubra

Hedera helix

Convex <5

VEGETATION

X

Quercus garryana

NAD 1983

NA

45.85883110

According to the ACIS Scappoose Industrial AP weather station, 0.07 inches of rainfall were received on the day of the site visit and 0.42 inches within the two weeks prior. Since October 1, 2024, 10.99 inches of rainfall were received, which is 88% of normal.

Rock outcrop-Xerumbrepts complex, undulating (Unit 45), 0% to 10% slopes; Non-hydric

A. Northwest Forests and Coast

0X

Tree Stratum (Plot Size: 30' r or ______)

-122.80065360

Sec. 3 T. 4N R. 1W

Wastewater System Capacity Improvements

City of St. Helens

St. Helens/Columbia 12/12/2024

P-1

WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys and Coast Region

Oregon

X

#DIV/0!

Sapling/Shrub Stratum (Plot Size: 10' r or ______)

Herb Stratum (Plot Size: 5' r or ______)

Rubus armeniacus

Remarks:

Remarks:

Problematic Hydrophytic Vegetation (Explain)1

50%

AKS Job 10363-04 USACE Western Mountains, Valleys and Coast - Version 2.0

% % Type1

Hydric Soil Indicators (Applicable to all LRRs, unless otherwise noted): Indicators for Problematic Hydric Soils3:

Histosol (A1) Sandy Redox (S5) 2 cm Muck (A10)

Histic Epipedon (A2) Stripped Matrix (S6) Red Parent Material (TF2)

Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Very Shallow Dark Surface (TF12)

Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Other (Explain in Remarks)

Depleted Below Dark Surface (A11) Depleted Matrix (F3)

Thick Dark Surface (A12) Redox Dark Surface (F6)

Sandy Mucky Mineral (S1) Depleted Dark Surface (F7)

Sandy Gleyed Matrix (S4) Redox Depressions (F8)

Restrictive Layer (if present):

Hydric Soil

Depth (inches): Present? Yes No

Wetland Hydrology Indicators:

Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required)

Surface Water (A1) Water-Stained Leaves (B9) (except MLRA Water-Stained Leaves (B9) (MLRA 1, 2, High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B)

Saturation (A3) Salt Crust (B11) Drainage Patterns (B10) Water Marks (B1) Aquatic Invertebrates (B13) Dry-Season Water Table (C2)

Sediment Deposits (B2) Hydrogen Sulfide Odor (C1) Saturation Visible on Aerial Imagery (C9)

Drift Deposits (B3) Oxidized Rhizospheres along Living Roots (C3) Geomorphic Position (D2)

Algal Mat or Crust (B4) Presence of Reduced Iron (C4) Shallow Aquitard (D3)

Iron Deposits (B5) Recent Iron Reduction in Tilled Soils (C6) FAC-Neutral Test (D5)

Surface Soil Cracks (B6) Stunted or Stressed Plants (D1) (LRR A) Raised Ant Mounds (D6) (LRR A)

Inundation Visible on Aerial Imagery (B7) Other (Explain in Remarks) Frost-Heave Hummocks (D7)

Sparsely Vegetated Concave Surface (B8)

Field Observations:

Surface Water Present? Yes No X Wetland Water Table Present? Yes No X Hydrology Yes No Saturation Present? Yes No X Present?

(includes capillary fringe)

0-12

X Depth (inches):

Depth (inches):

Depth (inches):

⁰Texture: S = sand; Si = silt; C = clay; L = loam or loamy. Texture Modifier: co = coarse; f = fine; vf = very fine; + = heavy (more clay); - = light (less clay)

1Type: C=Concentration, D=Depletion, RM=Reduced Matrix CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix.

3Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic.

X

Redox Features Depth

Sampling Point:

10YR 2/1

(inches)

Type:

SOIL

Profile Description (Describe to the depth needed to document the indicator or confirm the absence of indicators):

Color (moist) Loc2 Texture⁰ Remarks

SiL

Matrix

Remarks:

Color (moist)

Remarks:

Angular rocks throughout profile.

Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:

P-1

HYDROLOGY

Investigator(s): Section, Township, Range:

Landform (hillslope, terrace, etc.): Hillslope Local relief (concave, convex, none): Slope (%):

Subregion (LRR): Lat: Long: Datum:

Soil Map Unit Name: NWI classification:

Are climatic / hydrologic conditions on the site typical for this time of year? Yes No (If no, explain in Remarks) Are Vegetation 0 0 , or Hydrology significantly disturbed? Are “Normal Circumstances” present? Yes X No 0 Are Vegetation 0 0 , or Hydrology naturally problematic? (If needed, explain any answers in Remarks.)

SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc.

Hydrophytic Vegetation Present? Yes X No 0 Hydric Soil Present? Yes X No 0 Is the Sampled Area

Wetland Hydrology Present? Yes X No 0 within a Wetland? Yes No

Absolute Dominant Indicator Dominance Test worksheet:

% Cover Species? Status Number of Dominant Species

1. 5% Yes FACW That Are OBL, FACW, or FAC: (A)

2. 0

3. 0 Total Number of Dominant

4. 0 Species Across All Strata: (B)

5% = Total Cover Percent of Dominant Species

1. 20% Yes FAC That Are OBL, FACW, or FAC: (A/B)

2. 10% Yes FACW Prevalence Index worksheet:

3. 0 Total % Cover of: Multiply by:

4. 0 OBL species x 1 =

5. 0 FACW species x 2 =

30% = Total Cover FAC species x 3 =

FACU species x 4 =

1. 80% Yes FACW UPL species x 5 =

2. 0 Column Totals: (A) (B)

3. 0 Prevalence Index = B/A =

4. 0 Hydrophytic Vegetation Indicators:

5. 0 1 - Rapid Test for Hydrophytic Vegetation

6. 0 X 2 - Dominance Test is >50%

7. 0 3 - Prevalence Index is ≤3.01

8. 0 4 - Morphological Adaptations1 (Provide supporting

9. 0 data in Remarks or on a separate sheet)

10. 0 5 - Wetland Non-Vascular Plants1

11. 0

80% = Total Cover 1Indicators of hydric soil and wetland hydrology must Woody Vine Stratum (Plot Size: 10' r or ______) be present.

1. 0

2. 0 Hydrophytic

0% = Total Cover Vegetation Yes X No % Bare Ground in Herb Stratum 20% Present?

WETLAND DETERMINATION DATA FORM – Western Mountains, Valleys and Coast Region

Wastewater System Capacity Improvements City/County: St. Helens/Columbia 12/12/2024

City of St. Helens Oregon P-2 Julie Wirth-McGee, PWS, Emma Eichhorn, and Allison Law Sec. 3 T. 4N R. 1W

X

Precipitation:

According to the ACIS Scappoose Industrial AP weather station, 0.07 inches of rainfall were received on the day of the site visit and 0.42 inches within the two weeks prior. Since October 1, 2024, 10.99 inches of rainfall were received, which is 88% of normal.

Remarks:

VEGETATION

Convex <3

A. Northwest Forests and Coast 45.85878980 NAD 1983

Rock outcrop-Xerumbrepts complex, undulating (Unit 45), 0% to 10% slopes; Non-hydric NA X 0

-122.80067110

Fraxinus latifolia

Tree Stratum (Plot Size: 30' r or ______)

Fraxinus latifolia 4

Sapling/Shrub Stratum (Plot Size: 10' r or ______)

Rubus armeniacus 100%

#DIV/0!

Herb Stratum (Plot Size: 5' r or ______)

Phalaris arundinacea

Problematic Hydrophytic Vegetation (Explain)1

Remarks:

99 1 C

Hydric Soil Indicators (Applicable to all LRRs, unless otherwise noted): Indicators for Problematic Hydric Soils3:

Histosol (A1) Sandy Redox (S5) 2 cm Muck (A10)

Histic Epipedon (A2) Stripped Matrix (S6) Red Parent Material (TF2)

Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) Very Shallow Dark Surface (TF12)

X Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Other (Explain in Remarks)

Depleted Below Dark Surface (A11) Depleted Matrix (F3)

Thick Dark Surface (A12) Redox Dark Surface (F6)

Sandy Mucky Mineral (S1) Depleted Dark Surface (F7)

Sandy Gleyed Matrix (S4) Redox Depressions (F8)

Restrictive Layer (if present):

Hydric Soil

Depth (inches): Present? Yes X No

Wetland Hydrology Indicators:

Primary Indicators (minimum of one required; check all that apply) Secondary Indicators (2 or more required)

Surface Water (A1) Water-Stained Leaves (B9) (except MLRA Water-Stained Leaves (B9) (MLRA 1, 2, X High Water Table (A2) 1, 2, 4A, and 4B) 4A, and 4B)

X Saturation (A3) Salt Crust (B11) Drainage Patterns (B10) Water Marks (B1) Aquatic Invertebrates (B13) Dry-Season Water Table (C2)

Sediment Deposits (B2) Hydrogen Sulfide Odor (C1) Saturation Visible on Aerial Imagery (C9)

Drift Deposits…