Natural Resource Significance Determination and ESEE Analysis

[Pages:16]Natural Resource Significance Determination and ESEE Analysis

FILE NO: LU 03-0047 DATE: March 17, 2005 PROPERTIES:

Map 21E16D

TaxLot 01000

21E16D 21E16C 21E16C 21E16C

01100 00607 00608 00609

21E16CA 00700 TOTAL

Owner Bethlehem Baptist Church City of Lake Oswego Pete Wall Keith & Teri Oelrich Gregory & Stephanie Knecht Terrill & Janet Collier

Acres 6.01

9.8 2.0 2.0 2.0

7.05 28.86

INTRODUCTION

In 2003 the City of Lake Oswego initiated a land use planning effort to include six properties into the City's Urban Services Boundary (USB). This USB expansion process will result in application of urban comprehensive designations for the property. In addition, the City is required to determine the extent of natural resources on these properties and to evaluate the level of protection that will be applied at the time of City annexation and zoning of the properties. To add apply the City's environmental protection program (Resource Protection (RP) and/or Resource Conservation (RC) overly zone designation), the properties must be evaluated through an ESEE analysis in compliance with Statewide Land Use Planning Goal 5.

As a part of the process, the properties have been evaluated for the presence of natural resources. City staff utilize a variety of sources to determine whether natural resources exist on a property including: existing comprehensive plan and zoning maps, the Sensitive Lands Atlas, the draft update to the Sensitive Lands inventory prepared in 2003, aerial photos, and field visits.

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OVERVIEW

In 2003, in anticipation of the subject area being included in the USB, the City hired Fishman Environmental Services to conduct field assessments for this site and other properties in the City UGB. In order to more accurately evaluate the resource in preparation for conducting the ESEE analysis, the City's Natural Resource Coordinator conducted a site-specific analysis on 2/28/05. The inventory and data collection was done according to the same process as was conducted for the resources during the initial citywide inventory (on file at City under the title: "Lake Oswego Resource Areas Report & ESEE Analysis" Case file: PA2-97/2c 2-97).

Review of previous resource mapping and current aerial photographs shows forest canopy and a stream corridor within the study area. On February 28, 2005, the City's Natural Resource Coordinator, Lisa Hamerlynck, visited the study area to evaluate the quality and quantity of the natural resource. Ms. Hamerlynck was able to access the entire study area and prepare a site summary and Habitat Assessment Score (HAS) data sheet, which are attached (See Attachments A).

The study area includes six properties and comprises 28.86 acres. There is a headwater wetland, surface drainage channels, a stream, an associated wetland, and forest canopy that occupy the site. Approximately2.9 acres of contiguous tree canopy, stream corridor, and wetland are identified in the study area.

LOCATION AND QUALITY

The properties included in this assessment lie along or contain portions of Pecan Creek between Overlook Drive, Atherton Drive, Stafford Rd. and Meadowlark Lane. The resource area functions as headwaters to Pecan Creek, which drains to the Tualatin River. The resource area was identified during the Sensitive Lands Inventory and ESEE study (1992-1998) as IB-26B (the map is included as Attachment B).

The study area lies adjacent to the "COOKS BUTTE" Natural Area (NA12) identified in the 1994/95 ESEE study. The resources in the study area are similar to the ones evaluated in the Cooks Butte NA ESEE. There are at least four headwater streams which form Pecan Creek; the western fork starts in the SW corner of Cooks Butte, the next stream to the east starts on a recently acquired City property south of Atherton Drive, the center fork starts in the study area, and the east fork starts on the Luscher Farm property. Cooks Butte and Overlook Drive acts as the highest points of the Pecan Creek watershed and basin. All of the headwater portions of Pecan Creek are in ownership of the City of Lake Oswego.

In 2003, the City hired Fishman Environmental Services (FES) to complete an inventory of natural resources in Clackamas County within the City's Urban Growth Boundary. Christie Galen, of FES, conducted a general analysis of the resource in the study area. Galen completed the data sheets for the stream corridor from the vantage points of the

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gravel driveway access for the nursery and from Atherton Drive (she did not have permission to enter private property). Galen noted that site access was very difficult because Himalayan Blackberry plants covered most of the resource area. She recommended that the City remove the invasive plants and conduct a more accurate site analysis in the future. The stream corridor, which was previously identified in the City SL Map as IB-26A was given a site number of #2450. The proposed USB expansion was the trigger to complete the on-site evaluation and ESEE analysis.

SIGNIFICANCE ANALYSIS

Historic photos and maps show what appears to be a stream corridor with a forest canopy from Overlook Drive to the Tualatin River. There were likely seeps, springs, groundwater, and surface water in the study area, which contributed to the stream flow. The area has been altered by deforestation, farming, development of ball fields, the church, and upslope development.

In 2003, the City's Natural Resource Coordinator worked with wetland specialists to determine if the southern most Lake Ridge soccer field (just north of the nursery's gravel driveway) met DSL's criteria for wetland. It has been common knowledge for many years that the ball field is only useable during the driest months of the year. The wetland scientists determined that most of the ball field was a mosaic wetland and did meet DSL jurisdiction criteria. The southern edge of the ball field has a significant cut bank along the nursery driveway that seeps water to a culvert, which passes under the gravel drive to the south. Whereas this area is currently in the City and is not mapped as a resource, it functions as a headwater wetland and contributes significant hydrology to the stream.

There is a stormwater detention pond next to 2025 Ridge Pointe Drive at the highest point of the Collier's nursery property. The detention pond drains east along the nursery access road. The channel is approximately two feet wide and two to three feet deep. There are several pipes that drain to the channel from the north. The channel is rocky with a small amount of wetland plants. There is some vegetation along the northern side of the channel near the ball field. The channel crosses under the nursery access road at the NE corner of the nursery property. The outlet drains to two channels. One drains east and south to join Pecan Creek. The other channel is much more significant and has been altered in the recent past. This channel drains south along the eastern most nursery property line. It passes south onto the southern property owner's property before the channel turns towards pecan creek. This channel is large and had some water in it on 2/28/05. It may also be capturing groundwater and irrigation water from the nursery.

The northern reach of the stream has a distinct channel but was relatively shallow where the culvert outleted from under the nursery driveway. As you move south the channel became deeper and incised from erosion. It is interesting that the channel is so deeply incised whereas this is a headwater stream and the channel impacts are significant within the first two hundred feet of the stream from the culvert and the beginning of the stream. A ravine begins to appear as the slope to the east becomes steeper and as the stream enters the grove of large Douglas firs. The Douglas firs are upwards of 30 inches. The

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stream channel is approx. 5 feet wide in this area. Just south of the firs, the main channel spreads out with several channels and enters a wetland area approx. 30 feet wide. The wetland is characterized by willows, cottonwoods, and a lack of vegetation because it appeared to have been inundated with water during the winter. The wetland continues south, is channeled again on the property nearest Atherton dr. before it becomes a wetland again above the culverts at Atherton. The stream was flowing in the southern section near Atherton Drive. South of Atherton Drive, the channel spreads out and is a stream with associated wetlands again. There were at least three channels draining from the properties on the west side of the stream, which included the channel that runs along the eastern edge of the nursery.

The trees and habitat in the study area are connected to, and contiguous with, a very large area of upland forest (Cooks Butte), upland meadow (former farm land), and riparian habitat along a perennial stream and floodplain wetlands. The forest canopy contains native trees, predominately Douglas fir, cottonwood, cherry, and Pacific Willow. There are several horticultural trees species. There is structural diversity due to mixed age trees, mid-story shrubs (willow sp., hazel, and elderberry) and ground layer shrubs of ferns and snowberry. Invasive plants (ivy, hawthorn, holly, and blackberries) are present on the property. The City owned property is approximately 90% covered with Himalayan Blackberry and English Hawthorn.

This portion of Pecan Creek is unlikely to be a "fish bearing" stream, however, it drains into the Tualatin River which does contain federally listed fish species which accords it additional protection under state and federal regulations. In addition, under the regulations of the Clean Water Act, the Tualatin River is "water quality limited" for several parameters, which include temperature, fecal chloroform, and phosphorus. Activities along Pecan Creek that would contribute to these parameters would include chemicals (fertilizer, pesticide, herbicides), removal of vegetation and trees from riparian areas, and ponding of water.

The property was evaluated with the standard Wildlife Habitat Assessment form to determine the Habitat Assessment Score (HAS). Because the site contained a stream corridor, wetland and forest canopy, the site was evaluated for potential applicability of Resource Conservation (RC) designation and Resource Protection (RP) designation under the LOC article 50.16.

Galen assessed the resource to be a stream corridor with an associated riparian area. She determined the HAS score to be 51. Based on a more comprehensive site visit, City staff re-evaluated the site and determined the HAS score to be 53. The value increased slightly because Ms. Hamerlynck noted that the stream spreads out into a braided wetland in the southern portion of the stream corridor and she noted that there was education potential because a large portion of the resource is in City ownership, there are several City owned park properties nearby, and that Lake Ridge High School is within walking distance.

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The resulting Habitat Assessment Score of 53 meets the threshold of 50 as required in the 1994/95 ESEE study and a RP Class 1 ranking would be applied to the stream, and wetland. The adjacent forest canopy ranks high enough to qualify as RC because it is associated with a RP Class 1 resource. In conclusion, the site is determined to be significant and should be included in the City's inventory of natural resources.

CONFLICTING USES

Tax Id

21E16D 21E16D

21E16CA 21E16C 21E16C 21E16C

Lot

1000 1100

700 607 608 609

Acres

6.01 9.72

7.05 2 2 2

Proposed Plan Designation R-15 PARK/OPEN SPACE R-10 R-10 R-10 R-10

Owner

Church City

Private Private Private Private

Proposed Resource Overlay

Stream Buffer Stream/Wetland/Tree Grove

Stream/Tree Grove Stream/Wetland/Tree Grove Stream/Wetland/Tree Grove Stream/Wetland/Tree Grove

GENERAL CONFLICTING USE

Conflicting uses in the study area relate to protection of the resource, allowing appropriate densities of development, minimizing impact to the resources from development activities, and managing the resource in a sustainable manner with singlefamily homes, a high school, and park users adjacent to the resource.

Potential negative impacts to the natural resource resulting from the single-family development include: sediment from erosion, noise and light impacts, habitat disconnection, human and pet use impacts, road kill, vegetation impacts and tree blow down and scenic impacts.

These types of conflicts can be managed to some degree by limiting tree removal and restricting home locations to minimize the impacts to the size of the forest canopy. These conflicts can also be addressed as part of the development review process and through code enforcement

Conflicting uses associated with the City owned property are potential park improvements, which may include trails, shelters, picnic grounds, ball fields, rest room facilities and parking. There could be adverse environmental consequences from construction of park improvements and resultant increased use of the park. However, on balance, the social benefits of public use of a park generally outweigh the limited adverse environmental impacts -- under the following circumstances:

? Parking areas and other park improvements should be located away from steep slopes and natural drainage ways and should be designed to manage storm water and minimize tree removal.

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? Trails should be carefully maintained and designed to discourage and minimize erosion and damage to vegetation.

? Volunteer stewardship and increased management of the resource could result in a reduction of invasive species and the potential for restoration of the stream corridor for improved wildlife habitat.

? There is an unrealized educational opportunity with the Lake Ridge High School and an opportunity for environmental interpretation panels to be included in park development.

LOT SPECIFIC CONFLICTING USES

Tax Lot 1000 is currently developed as a church with associated asphalt parking area. The proposed plan designation is R-15. The actual stream resource is a very small portion in the SW most corner of the property. If the stream resource is designated as an RP-1 resource as is proposed, Tax Lot 1000 would be affected mostly by the 30-foot buffer and 10 foot construction setback. Currently the proposed buffer area is mowed grass with a few ornamental trees and asphalt parking area. The estimated acreage of resource on the tax lot is .05. At the current time there is no conflicting use with the resource. If this property redevelops in the future to residential (R-15), it would likely do so as a Planned Development and under those provisions be required to meet the open space requirements. The resource area would qualify as open space. Based on the location of the resource on the site, environmental protection of the resource would not have a significant impact on redevelopment or expansion of uses on the site.

Tax Lot 1100 is a 9.72-acre City owned parcel. It was purchased for park property. As part of the USB expansion, the plan designation for the site is proposed to be "Park/Open Space". Whereas the property does not have a master plan, likely park amenities include: trails, shelters, picnic grounds, ball fields, rest rooms and parking as mentioned above in the general conflicting uses discussion. This property has the largest portion of resource proposed within the study area at 1.9 acres. Whereas this is a large portion of the site, it does not preclude any of the mentioned park development from occurring.

Park use of the site would require conditional use approval by the Development Review Commission (DRC). The DRC would apply all City Code requirements addressing public utilities and facilities and storm water runoff. Based on the location of the resource on the site, environmental protection of the resource would not have a significant impact on park use on the site.

Tax Lot 700 is a 7.05-acre parcel up slope of the resource. The parcel has approximately 0.2 acres of resource proposed for designation. The parcel currently has a single family home and a small nursery operation. The proposed plan designation for this property is R-10. This level of density on a moderate to steep slope above a resource has the potential to result in negative impacts to the resource. The property will likely develop as a Planned Development (PD). During the PD planning process, applicable city codes will help to minimize development impacts to the resource. The PD process also triggers

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openspace preservation requirements. Openspace designation and sensitive lands (SL) resources can overlap and will likely result in protection of the proposed resource.

The most significant potential impacts to the resource that would result from development of this property into several single-family lots are: construction impacts, increased impervious surfaces, concentrated stormwater flow, and the general conflicts from humans and pets. Conflicts with the preservation of the resource and reducing negative impacts to the resource from development can be achieved with stringent erosion control measures, environmentally sensitive development practices, and improvement of the existing open water surface drainage ways.

At some point in the past, there was a stormwater facility constructed in the NW corner of the property to manage the flow from upslope development. The detention pond outfalls to a significant drainage channel along the northern property that runs down hill in a highly eroded channel. The drainage passes under the access driveway for the nursery at the NE corner of the property. After passing under the road, it has been divided into a small channel that runs east and joins the stream, and a second channel that runs along the eastern property line of the parcel and cuts across tax lot 607 to the south before joining the creek. The channel along the east property line has been recently constructed to carry a large volume of water. It may also capture runoff from the nursery, surface or spring water, and groundwater. The channel is actively eroding but does have some wetland vegetation. In discussions with wetland specialists, both the channel along the north property line and the east property line would likely not qualify as Goal 5 resources because of lack of vegetation, however, the channels still carry "waters of the state" and any impacts to the "natural" drainage ways must be evaluated and permitted by DSL and or the Corps of Engineers. Both of these drainage ways should be evaluated during the development review process to require improved functions for water quality and quantity reasons.

Based on the location of the resource on the site, environmental protection of the resource would not have a significant impact on residential development of the site.

Tax Lots 607, 608, and 609 are three 2-acre parcels that currently have existing singlefamily homes on them. They are proposed for an R-10 plan designation. The proposed resource designation will cover approximately 0.5 acres of Tax Lot 607, 0.3 acres of Tax Lot 608, and 0.1 acres of Tax Lot 609. Additional development on these properties may occur but slope and access will limit densities. A roadway could be designed to cross the properties up hill from the resource area. This could provide two building sites on each property overlooking the resource area. Conflicting uses could include encroachment into the resource and general activities associated with single-family development including: construction impacts, increased impervious surfaces, concentrated storm water flow, and the general conflicts from humans and pets.

The proposed natural resource designation on the site is located along the eastern property line adjacent to City park property. Based on this location, environmental

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protection of the resource should not have a significant impact on further residential development of the properties.

IMPACT AREAS

The natural resources in the study area consist of a stream corridor with an "in-channel" wetland complex, and associated forest canopy that connects with resource and forested areas to the south. The resource area is fairly well defined headwater stream with moderate to steep slopes to the north, east and west. In the broadest interpretation of impact area for the resource, the impact area would be any property upslope that affects the surface water, groundwater, or hydrology of the site. Because of existing City code and development requirements for erosion control and surface water management, it is determined that only those properties that directly abut the proposed resource areas will be defined as impact areas.

ESEE ANALYSIS

ENVIRONMENTAL CONSEQUENCES

Over time, there have been significant environmental changes in the study area from forest and stream corridor to farmland and now residential. Historic impacts to the resources have been detrimental and resulted in: limited forest canopy for the stream, seeps and wetlands at the headwater graded and filled, changes in frequency and volume of surface water which has resulted in a down cutting and highly eroded stream channel, and approximately 80% of the understory is invasive Himalayan blackberry.

By applying the sensitive lands overlay zone to the resource areas, the resource can be protected while also allowing development of single-family homes and park amenities. There is also a high likelihood that the resource can be significantly improved with proper surface water management, invasive plant eradication, and riparian vegetation restoration. The City has also recently purchase a large parcel of property to the south of the study area that includes the stream and connects this resource to Cooks Butte park and two other forks of the Pecan Headwater streams. This larger area of protected habitat will be able to maintain a greater diversity of plant and animal species as well as provide for the long-term protection of habitat for species that require larger habitat core areas. Examples include: Deer, Pileated woodpeckers, Red legged frogs, and old growth trees.

Fully allowing the conflicting uses (additional residential development in the resource area) would result in a loss of habitat and tree cover. Limiting or prohibiting the conflicting use would retain tree cover and enhance wildlife habitat.

SOCIAL CONSEQUENCES

In Lake Oswego, the trend has been for property owners and developers to choose to build on larger lots rather than to maximize density. This trend results in larger lots with

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