Urban Natural Resources

City of Silverton Climate Action Plan

Claire Gillies; Brendan Walsh; Aaron Woolverton

LA 4/510 Design for Climate Action

Professor Yekang Ko

March 3, 2020

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Table of Contents

Background Research 2

Silverton’s GHG Emissions 4

Urban Natural Resources Organizations and Important Players 5

Existing Urban Natural Resources and Facilities 5

Climate Action Framework 7

Vision 7

Goal 1 | Revitalizing the Urban Forest 7

Goal 2 | Access to Clean Water 9

Implementation & Monitoring 10

Specific Planning and Design Recommendations 12

Recommendations for the Comprehensive Plan 17

Works Cited 18

Background Research

Urban systems should seek to provide the natural resources necessary to reduce greenhouse

gas (GHG) emissions and the subsequent impact of global climate change. According to the IPCC’s latest

report on climate change, the world is to reach an average warming of 1.5° celsius between the years

2030 and 2052, (Intergovernmental Panel on Climate Change, 2018) while other models suggest an

increase between 1 to 3.5° celsius by the year 2100.(Nowak et al., 2002) With this projection comes the

expectation that there will be an increase in extreme weather events, a steep rise in seasonal

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temperatures, and potential for longer drought seasons. This report also supports the need for quickly

integrating mitigation and adaptation measures for the security of livelihoods.(Intergovernmental Panel

on Climate Change, 2018) Although a majority of the United State’s GHG emissions result from the

transportation and electric power sectors - approximately 29% and 28% respectively, (US Environmental

Protection Agency, 2018) there is a need to focus on urban natural resources and its place in the

discussion for climate action.

The United States Forest Service defines urban natural resource management as the sustainable

approach towards maintaining the positive feedback provided by parks, trees, greenways, ecological

infrastructures, and water sources.(USDA Forest Service) These natural features are incredibly important

for urban environments because they provide social well-being, ecological health, and civic stewardship.

(Campbell & Wiesen, 2009) Additionally, these elements provide opportunity for resilience to the

pressures of climate change through drawing down carbon, establishing biodiversity, and regulating

climates. (Vargas-Hernández et al., 2018) Fortunately, the city of Silverton has an ecologically oriented

agenda - several actions in their master planning documents reveal the mindfulness they have towards

the environment and clear objectives towards maintaining healthy ecosystems. In order to understand

the potentials for mitigating GHG emissions, we must consider actions and methods other cities have

considered for their climate action plans.

In reference to Portland's Climate Action Plan, a predominant emphasis was placed onto the

ecological services provided by trees. Their plan reinforces the idea that urban forests have twice the

potential to offset carbon emissions than non-urban forests due to faster growth rates, increased focus

on mature trees, and the secondary effects of reducing building energy uses by cooling down

environments. (Nowak et al., 2013) They focus on vulnerable neighborhoods that may be impacted by

increased temperatures due to the Urban Heat Island effect. Portland also prioritizes the health and

maintenance for street trees, especially in the face of a changing climate. They have adopted a “Tree

Code”, ( Portland Climate Action Plan, 2015) which regulates the diversity, distribution, and selection of

climate appropriate, low maintenance across the entire urban fabric. Portland’s Tree Code is especially

important for lowering GHG emissions - this policy has a direct impact on the emissions and

sequestration potential for urban forests. According to Nowak et al., “Critical forest management factors

in maximizing carbon benefits include species composition, life span, maintenance, decomposition, and

energy conservation.” (Nowak et al., 2002) This tree code encourages native tree planting which

requires less maintenance, longer life-cycles, and ecological function; therefore, increasing carbon

sequestering capacities while lowering emissions through maintenance regimes and decomposition.

While the City of Corvallis' Climate Action Plan also provides strategies for urban canopy and

forest management, they emphasize the need for water resource management by incorporating more

stormwater facilities, rain-water capture systems, as well as long term storing of water for iminent

drought seasons. (Corvallis Climate Action Plan, 2016) As we see an increase of extreme weather events

and atmospheric temperatures, Oregon’s snowpack is to decline 60% by 2040, which will result in

higher, peaking stream flows earlier in the year and lead into longer drought seasons.(Bob Doppelt,

2009) Corvallis’ actions on preserving water resources, like working with local agencies to increase

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conservation efficiency, is important in terms of providing resilience to the uncertainties of climate

change as well as reducing GHG emissions. (Corvallis Climate Action Plan, 2016) With this, some climate

models show a slight increase in precipitation - especially in singular storm events. (Bob Doppelt, 2009)

In response to this, Corvallis has incorporated a focus on stormwater infiltration, pipe daylighting, and

restoring stream sides to reduce the potential for flooding, landslides and destabilizing

grounds.(Corvallis Climate Action Plan, 2016)

Silverton’s GHG Emissions

GHG emissions and inventory analysis is not straightforward when it comes to urban natural

resources as a sector. Although it is unclear which urban natural sources produce the most GHG

emissions in Silverton, we have found literature that identifies landscape maintenance, carbon

sequestration, urban form, stormwater management, and access to recreation as key areas for

reducing greenhouse gas emissions. These natural resources provide opportunity for reducing and

storing carbon levels throughout the city of SIlverton. With this, several Master Planning documents

reference these sources as priorities for Silverton’s development. In reference to the Parks and

Recreation documents, Silverton has highlighted existing parks and greenways, like silver creek, as

places for adequate implementation. Ultimately, they may enhance ecological function while providing

the community more resilience to changing climatic conditions and uncertainties:

1. Landscape Maintenance:

Maintaining landscapes requires an excessive amount of carbon; this principle applies

across all land-uses. According to the Environmental Protection Agency (EPA), the United States

emits approximately 26.7 million tons of greenhouse gasses annually through the use of gas-

powered lawn equipment. This accounts for 24% to 45% of all off-road gasoline emissions. (EPA ,

2011-18) With this, the maintenance of non-native trees within a landscape will eventually lead to

greater carbon emissions than offsets by the end of the tree's life. (Nowak et al., 2002) In

another study by Stephen J. Livesley et al, maintenance of lawn and mulched systems generate

more carbon over time. It is also recommended to limit the use of hedges and topiary as a

means to reduce maintenance emissions. With this, limiting the use of annual plants and

planting more perennials will reduce consumption and provide long-living potential for carbon

sequestration. Therefore, emphasis on planting a diversity of native, perennial species will

boost ecological function and store more carbon in the long-run.(Stephen J. Livesley, 2010)

2. Carbon Sequestration:

Urban forests store more carbon efficiently than any other forests in the country; we

should be focusing our efforts and management on these forested systems like other US forests.

According to Nowak, U.S. urban forests store around 640 Million tons of CO₂. annually while

urban forest canopies sequester an average rate of 7.46 kg carbon per square meter. If we add

together the sequestering impacts of community lands with urban forest canopies, the total

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equates to over 1.47 billion tons of carbon sequestration annually. (Nowak et al., 2013) Nowak

et al.’s study suggests that the maintenance of these canopies will become increasingly

important as time goes on. In reference to other research, the longer the tree’s life, assuming no

need for increased maintenance efforts, the greater the carbon benefit received from the tree.

(Nowak et al., 2002) Cities around the world have started Urban forestry management practices

to ensure a healthy livelihood and sustainable life-cycle for these natural resources. As an

example, in San Francisco, the use of urban wood for logs and lumber represents a responsible

way to reduce consumption. Not only does keeping the wood intact sequester the tree’s carbon,

it also provides a usable product that has tangible value. (Jonathan Dirrenberger et al., 2014)

3. Stormwater Management:

The management of our waters is incredibly important for the livelihood and

functioning of our local ecosystems. Energy use by drinking water and wastewater facilities

accounts for approximately three percent of the United States' energy consumption - which

equates to the energy used by 10 million cars annually. (US Environmental Protection Agency,

National Water Program Strategy) Healthy soils require natural ecological processes. In order to

sequester more Carbon and reduce stormwater loads. With this, water should be daylit and

infiltrate soils to improve microbial diversity. (Stephen J. Livesley at al., 2010)

Urban Natural Resources Organizations and Important Players

Silverton’s core values from the Parks and Recreation Master Plan outline its need for

walkability and connectivity, protecting natural beauty, large greenspace areas, raising children in a safe,

livable community, and community health and well-being. Land use integrated with parks and open

space desire for community health and well-being, which is possible through local, state and federal

involvement, but is ultimately determined by local businesses and residents across the community. The

organizations that support the implementation and maintenance of SIlvertons urban natural resources

are the Urban Forestry Program, the Pudding River Watershed Council, Izaak Walton League of America,

and Silverton City Council teams that consist of The Green Team, and Sustainable Silverton. These

organizations are a good starting point for tackling the revitalization of the urban forest and providing

reliable access to clean water in Silverton. Working with these organizations more through community

led volunteering, and partnering with local, state, and federal assets on projects and policies will move

Silverton to a city with lower energy use, community involvement, and adaptability to increasing climate

change effects in the future.

Existing Urban Natural Resources and Facilities

Crucial facilities to the health and maintenance of Silverton’s urban natural resources are the

Silverton Wastewater Treatment Plant, Silverton Parks and Recreation, the city Pool, stormwater

detention areas and basins, and the Silverton Community Center, The Oregon Garden, and the Oregon

Garden’s Pettit Reservoir. organizations like The Silverton Community Center, Silverton Parks and

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Recreation, and more specifically, The Oregon Garden have done extensive work in Silverton with

educating the public about the importance of Silvertons’ natural resources and information about it’s

forests, wetlands and wildlife. Currently, the city pool uses a lot of energy and natural resources, but

it's an important part of contributing to the recreational uses and well-being of the city. The Silverton

Reservoir provides a backup municipal water source for Silverton, serves as a recreational resource, and

relies on an unimpeded upstream flow of clean water from Silver Creek. The Silverton Wastewater

Treatment Plant has been given innovation awards, and takes care of Silvertons drinking water supply,

treatment quality, and pumping stations. This division is also responsible for the treatment of

wastewater, clean effluent disposal and treated biosolids disposal. The Water Quality Division delivers

over 600 million gallons of high quality drinking water to residents and business customers annually

(“Water Quality Division: Silverton, OR - Official Website.”). These existing urban natural resources and

facilities in Silverton contribute to meaningful reductions in carbon emissions while fulfilling the core

values Silverton upholds. Developing strategies to work with, maintain, and sustainably develop this

existing infrastructure of natural resources will be necessary for the future of Silverton.

Hazard Mitigation

Silverton has relatively high populations of both school age children, and senior residents. Both

of these populations are especially vulnerable in climatic situations. Disaster preparedness training and

improvements in schools and nearby communities will be beneficial. Encouraging community resilience

and communication will also protect these vulnerable residents. Strategies to encourage neighbors to

keep lists of each other's phone numbers and emergency contacts could be considered. Close-knit

communities provide valuable support to residents, a support system they might otherwise lack. Actions

outlined in this plan specifically increase Silvertons resilience to the following natural hazards.

Earthquake Summary

Type: Geologic

Location: Primarily west of the Cascades; CA - BC

Speed of Onset: Rapid

Extent: Catastrophic

Prior Occurrence: One over Magnitude 9 last 500 yrs

Probability: Magnitude 9+ is 7% - 12% over 50 yrs

New construction in Silverton must meet standards for earthquake resilience. Continue to work

on Robert Frost Elementary / Mark Twain Middle schools that are “high” (>10%) “probability of collapse.

Earthquake probability is unaffected by climate change. Planners should be careful not to forget

earthquake preparedness when designing a new system.

Flood Summary

Type: Climatic

Speed of Onset: Slow to moderate

Location: Mapped flood zones, floodplain

Extent: Moderate to Severe

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Prior Occurrence: Four significant events since 1964

Probability: 1% annual

As snowpack melts in the mountains and climate change produces larger, more frequent storm

events, Silverton can expect to see flooding in the future. The damage and extent of the flooding will be

determined by the efforts made to develop and maintain riparian zones, as well as decisions made by

city planners in future endeavors. Increased streamside vegetation will reduce erosion during high flow

periods. Minimizing erosion is beneficial to ecosystems and to nearby developments. Improving

stormwater management systems will reduce runoff pollution and residential flooding in high flow

periods.

Drought Summary

Type: Climatic

Speed of Onset: Slow

Location: Varies, County Wide

Extent: Moderate to Severe

Prior Occurrence: Three > 6 months duration since 1982

Probability: ~9%

Drought will become more common for Silverton and Willamette valley residents. As climate

change shifts seasonal wind systems, we are seeing longer and longer summer periods without rainfall.

Silverton sources water from the Abiqua, and can utilize Silver Creek as well if necessary. Improving

Silverton’s overall water conservation will improve drought resilience. (University of Oregon, 2017)

Climate Action Framework

Vision

“Silverton places a high priority on community health and well-being by ensuring access to

nature and recreation for all ages, and celebrating the arts and its artists. As a livable and welcoming

community, Silverton is a major destination area and vital part of a thriving tourism region.” (Silverton

Parks and Rec Master Plan pg. 6 - Planning Docs)

We envision a Silverton that has successfully provided access to natural resources while

reducing greenhouse gas emissions through the mindful management of healthy urban forests systems,

ecologies, and green infrastructures.

Goal 1 | Revitalizing the Urban Forest

Revitalizing the urban forest requires establishing relationships with existing management

organizations, incentivizing low maintenance landscaping policies, and strengthening ecological

resources. Ideally, a healthy urban forest will reduce risks and impacts from heat, drought and wildfire

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by preparing for hotter, drier summers with increased incidence of extreme heat days. Over time, the

goal is to reduce these stressors while sequestering excessive carbon.

Strategies

1. Work with the Parks and Recreation Department to evaluate and monitor street trees and

vegetation, modify species selections as appropriate to address climate change; this includes

planting adaptable natives that provide shade.

Actions

- Work with local agencies or universities, like PSU’s “Sustaining Urban Places Research

Lab”, to analyze the impact of raising temperatures absorbed by the city, also known as

“Heat Island Effect”.

- Develop new standards for street trees that may be more adaptable to Oregon’s

changing climate; implement this into Silverton’s Street Tree permittal process.

- Silver Creek Greenway and hillside should receive a high priority, removing invasive

vegetation and replanting with native plant material (Silverton Parks and Rec Master

Plan pg. 78 - Planning Docs).

2. Create landscaping policy for facilities and residents that consider options for using native

vegetation, firewise/waterwise landscaping, rain gardens, and electric maintenance tools.

Actions

- Create purchasing policy specifying electric lawn mowers, chain saws, leaf blowers, and

weed eaters.

- Encourage planting trees on the Western and Eastern sides of houses.

- Develop a community-led standard and certification process to incentivize the use of

native vegetation and waterwise landscaping; Incentivize and endorse communities to

plant “micro-wetlands”. This will reduce stormwater runoff and recharge natural water

systems.

- Prohibit the use of glyphosate fertilizers, such as Mansato’s RoundUp Weed killer,

throughout the city.

3. Work with local environmental groups, Silverton Parks and Recreation, and the Pudding River

Watershed Council to create both large and small networks of natural areas with diverse

functions and habitats to provide resilient futures adapting to increasing heat and floods.

Actions

- Work with local environmental groups and agencies to assess current ecological

diversity and develop a plan for conserving these resources.

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- Provide adequate recreation facilities to support and accommodate recreation needs;

work with schools to provide joint use of sports facilities (Silverton Parks and Rec Master

Plan pg. 8 - Planning Docs).

- Silver Creek corridor will be managed as a greenway link for wildlife habitat (Silverton

Parks and Rec Master Plan pg. 8 - Planning Docs). Consider other areas and parks for

habitat connectivity throughout the city.

- Work with the Pudding River Watershed Council and Parks and Recreation to maintain

the health of the Silver Creek Reservoir.

- Develop a plan with the Oregon Gardens to maintain the health of Pettit Reservoir.

Goal 2 | Access to Clean Water

Promote use of natural systems and practices for stormwater management with an emphasis on

cleansing and filtering urban runoff. Prepare for increased climate change effects to reduce Silverton’s

vulnerability to drought and utilize future increased flood levels.

Strategies

1. Improve stormwater management resources in key areas to better handle high flow situations

and reduce runoff pollution.

Actions

- Modify existing vegetated medians to accept stormwater flows and revise current codes

to require this stormwater management system at major intersections of peak flows.

- Reduce piped stormwater flows and peaks by incorporating public stormwater assets

that infiltrate, store and slow peak stormwater flows.

- Stormwater catch basin at the community center should be emulated in other areas

such as the swimming pool parking lot. Partner with Portland State students who are

already working in this area. (Silverton Parks and Rec Master Plan pg. 78).

2. Create healthy wetlands, streams, and drainageways throughout Silverton by working with

community-led organizations and the Pudding River Watershed Council.

Actions

- Establish habitat restoration plans along the Silver Creek Greenway and consult with a

Landscape Architect to develop schemes for this community asset.

- Prioritize riparian zones and stabilize streamside slopes throughout the watershed in

preparation of greater stormwater events. Consider utilizing ‘A Guide to Riparian Tree

and Shrub Planting in the Willamette Valley: Steps to Success.’ (Withrow-Robinson, Brad,

2017)

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3. Modify existing city codes to require designers and contractors to plan all new buildings with

green infrastructure.

Actions

- New facilities and buildings shall be required to implement water catchment systems -

such as cisterns - to reduce the need for treated water from the city.

- New buildings and remodels should be encouraged/incentivized to meet the Oregon

Reach Code. (ORC) 2011

4. Modify the water utility rate system to better serve the community and encourage water

conservation.

Actions

- Determine desirable monthly utility costs for residents. Eliminate or greatly reduce the

base charge and increase use charge to an appropriate level. Start by garnering

community input to determine new rate changes. This input could take the form of

committee of volunteers, an online survey or door to door polling.

Volunteering and Grants: Improvements to stormwater management systems and the Silver Creek

riparian zones are the costlier actions. Ideally much of the planting work in riparian zones could be done

with the help of volunteers from the community, or local habitat restoration organizations. The Marion

Soil and Water Conservation District offers grants to organizations working to improve soil and water

ecosystems in Marion county.

Implementation & Monitoring

Silverton should reach out to its residents for input on the new water rate system. Residents

should be notified of an opportunity to give input on a new water rate structure. Various strategies to

obtain usable community feedback should be considered. Forming a committee of community members

who accurately represent the demographics of Silverton is ideal.

Alternatives include a simple survey, distributed via email. A low cost/effort method, sending

the survey with residents water bills or at the same time of the month could increase response rate.

Door to door polling could be considered if other methods prove ineffective. Regardless of methods the

current water utility system and the proposed alternatives must be clearly and concisely explained to

residents. Providing a small incentive could increase response rates in survey or door to door methods.

A simple deduction from the next water bill is an obvious incentive.

The Finance Department will meet with the City Council to determine if community response is

accurately representative before moving ahead with new water rate designs. Requiring the survey to

have a minimum response rate for all neighborhoods could be a baseline for survey effectiveness. After

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implementation of the new system the Finance Department and City Council must examine trends in

resident bills and water use and determine effectiveness of the new system. A check in 1, 3, 6 and 12

months after implementation will allow for accurate assessment of information and informed decision

making in the future. Consider questions like: Do residents' bills better represent their water usage? Has

there been a net increase or decrease in water usage? How have high and low income communities

been affected? Allowing for the communities continued feedback on the new system in the form of

further surveys or polling is advisable.

Timeline

April 1-25th, 2020 - Finance department and City Council meeting to determine method of gaining

community input. If using a survey method, deliver it with the April water bill.

May - June, 2020 - Continue method of garnering community response. A survey could be sent at least

two times, with each water bill cycle, or more during this period.

June 22-26, 2020 - The Finance Department and City Council meet to determine if community response

results are sufficiently representative. Socioeconomic demographics must be considered when analyzing

results. If results are sufficient, work may continue designing the new system.

June 26 - July, 2020 - The Finance department designs a new water utility rate system. Economic status

of both the city and its residents, as well as resource conservation should be taken into consideration.

July 27-31, 2020 - City Council meets with the Finance Department to discuss the proposed system. If an

agreement is reached, move on to implementation.

August, 2020 - Prepare to implement a new water rate system starting the month of September. Inform

residents of upcoming changes.

September 1, 2020 - New rate system takes effect.

October 19-23 - First ‘check in’ meeting. The Finance Department and City Council examine usage rates

and bills from September. Comparing this data to past September datasets may be useful. If radically

undesirable trends are obvious, regressing to the previous system while new strategies are examined is

advised. Continuing to invite community feedback on the new system with surveys or public forums may

also be beneficial.

December 21-25, 2020 - . Three month check in meeting for the City Council and finance Department.

Data from community responses as well as bills and usage should be examined.

March 22-26, 2021 - Six month check in meeting.

Oct 18-22, 2021 - One-year check in meeting. Need for further meetings can be discussed.

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Specific Planning and Design Recommendations

Part 1: Revitalizing the Urban Forest and Recommending Green Infrastructures

Understanding the existing green infrastructure and public assets of a city is important when

planning a green infrastructure network. Taking information provided by Sustainable Silverton and the

City of Silverton, we provided a map that highlights existing assets and their recommendations of

important Urban Natural Resources to emphasize. Figure 1.1 reveals these areas, which include the

Oregon Gardens, Pettit reservoir, Silver Creek and associated Reservoirs, as well as Webb Lake. Our

process included exchange via verbal and email feedback, taking into account the experiences and

personal beliefs of current Sustainable Silverton Members and several City Board Officials. Ideally, these

maps will provide the city a guideline for their development - exposing prime areas for adaptive

measures like stormwater facilities, street tree planting, and potential urban wetlands.

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Figure 1.1 | Green Infrastructural mapping and existing Natural Resources Inventory. Areas mapped in light green include

existing natural infrastructure necessary to manage especially in the face of climate change. Green dots represent existing parks

throughout the City.

Our team then decided to overlay existing natural assets, Figure 1.1, on top of Priority areas

assessed by the Keller associates. These priority streets and points were extrapolated from the Keller

Associate’s maps, which may be found here:

https://www.silverton.or.us/DocumentCenter/View/3364/Silverton-SWMP---Final--July-2-2012?bidId= .

These assessments provide insight on areas where flooding will occur as well as potential

streamside destabilization due to piped stormwater flows and changes in extreme weather. Figure 1.2

also alludes to areas of intersection, where we may be able to provide co-benefits based on existing

natural resources and proposed green infrastructure.

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Figure 1.2 | Existing natural resource asset mapping overlaid on top of piped stormwater, drain outlets, and priority flood

zones. It reveals the potential problems that the city may see with climate change.

These assessments provide insight on areas where flooding will occur as well as potential

streamside destabilization due to piped stormwater flows and changes in extreme weather. Figure 1.2

also alludes to areas of intersection, where we may be able to provide co-benefits based on existing

natural resources and proposed green infrastructure.

Figure 1.3, below, looks at developing a green network system throughout the city of Silverton.

This network features urban wetlands, green streets, and urban bioretention facilities that are

strategically placed in reference to the intersections found in Figure 1.2. We intend for these green

streets to incorporate both stormwater facilities, increased shrub vegetation, and native street tree

planting. All together, this green infrastructure network should reduce Urban Heat Island effect,

stormwater loads on Silver Creek, and provide more aesthetic beauty throughout the city.

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Figure 1.3 | Existing natural resource asset mapping overlaid on top of piped stormwater, drain outlets, and priority flood

zones. It reveals the potential problems that the city may see with climate change.

In the attempt to visualize how these green infrastructures may look and feel along Silver Creek,

we included a representational section below, Figure 2. This section includes strategies that feature

mindful approaches towards ecological design. Although some of this is supplemental to green

infrastructures, recommending management for oak savanna and mixed forest habitats will increase

ecological diversity and resilience in the future. We strongly recommend incentivizing the use of cisterns

throughout residential neighborhoods as well as the use of native vegetation in residential yards. We

also suggest providing a larger riparian buffer along Silver Creek. This buffer will decrease the likelihood

of stream destabilization, reduce flooding events, as well as provide more habitat for sensitive animals.

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Figure 2 | A representational section through the Silver Creek Corridor suggesting strategies and actions to increase resilience

to future climate change.

Part 2: Restoring the Silver Creek Riparian Forest

Our biggest goal is to incorporate native Oregon broadleaved and conifer trees, shrubs,

groundcovers and perennials for erosion control, stormwater management, and many other co-benefits

for Silverton. The list of co-benefits for an urban forest is extensive and even more so if the species are

native to the area. Benefits include environmental, economic, health, and social benefits. This should be

considered important for urban natural resources because it overlays and provides co-benefits in several

areas of sustainable development. Native Oregon vegetation means these specified plants will be low

maintenance, provide healthy places for people to live, mitigate urban heat island effect, conserve

water, create healthy habitats for wildlife, and other aesthetic values.

Species of conifers, broadleaved, shrubs, groundcovers, and perennials to use based on native standing,

drought tolerance, and flood tolerance include:

Conifers: Ponderosa Pine, and Oregon White Oak.

Broadleaved: Black Cottonwood, Red Alder, Willows, and Aspens.

Shrubs: Western Hazelnut, Thimbleberry, Red-Twig Dog, and Rhododendron.

Groundcovers and Perennials: Rushes, Swordfern, and Tufted Hairgrass.

There are six steps outlined by Oregon State University to help landowners, watershed council

members, agency personnel, and others communicate about, plan, and implement successful riparian

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tree and shrub plantings specific to the Willamette Valley.(Withrow-Robinson, 2011). These six steps

include:

1. Plan your project.

2. Select and obtain plant materials.

3. Prepare the site.

4. Plant your trees right.

5. Take care of the planting.

6. Monitor and learn from results.

Figure 3 | Riparian restoration and streamside stabilization outlined for the Silver Creek Corridor through Silverton.

The plan is to introduce these trees and vegetation species on the banks of the Silver Creek and

other high priority areas of stormwater runoff, areas where there are no preexisting tree canopy, and

through a greenway from downtown Silverton by way of Silver Creek to the Silverton Reservoir. The

plants recommended in the section above include native, bank stabilizing species. This plant selection

would be helpful when deciding which plants to use along the Silver Creek corridor.

Recommendations for the Comprehensive Plan

The comprehensive plan begins with the changes that have occured in Silverton since 1979. This

section outlines new sewer and water systems and an increase in urban growth boundaries along with

other developmental changes in the past years. However, it does not explain the growing effects of

climate change on the categories now considered to be Silvertons urban natural resources. It does talk

about industrial expansion into the city and a determined increase in population in the near future,

which would have effects on the urban natural resources of Silverton. Moving on through the

comprehensive plan, the goals are stated in order from one to fourteen. Goals 6,7, and 9 cover topics

like sewage treatment, floodplain regulations, and water system capacity. The comprehensive plan’s

focus on water quality is great, and will continue to be important. In goal number 7 the comprehensive

plan covers floodplain regulations and slide hazard regulations which are connected to stormwater

maintenance and adaptation qualities. The plan neglects to describe the specific details of the

vegetation that will be implemented for floodplain and slide hazard reduction. It does not comment on

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the use of native species being a key part of the side of river vegetation to mitigate the hazards that

come with high level floods. This is important because climate change will result in higher flooding in the

near future. Making small changes, like prioritizing native vegetation over non-native a noteworthy

suggestion for Silverton to consider. Another thing that the comprehensive plan could introduce is a rate

system for water use. This is not something that is currently in the plan, but could save people money,

and also incentivize water conservation.

Another aspect of the comprehensive plan that is currently not included is the implementation

and suggested importance of an urban forest. Goal 13 includes a desire for a reduction of energy use by

way of methane gas recovery at the wastewater treatment plant. It does not cover any future plans to

create a thriving urban forest which is considered to be very instrumental in reducing greenhouse gas

emissions through carbon sequestration. There is a section under the Housing category of the

comprehensive plan that calls for “provisions of street trees”(Silverton Comprehensive Plan, 2002). This

is a great policy to reach for housing requirements, but this plan needs more details about what trees to

plant, how to plant them, and how to maintain them. These types of resources and delegation are

lacking both in the Silverton Energy Plan and the Silverton Comprehensive Plan. An organization called

the Urban Forestry Program provides this type of support and could be utilized in the future. This

organization is not mentioned in the Comprehensive Plan.

Works Cited

Akbari, H. (2002). Shade trees reduce building energy use and CO2 emissions from power plants.

Environmental Pollution, 116, S119–S126. https://doi.org/10.1016/S0269-7491(01)00264-0

Akbari, H., Pomerantz, M., & Taha, H. (2001). Cool surfaces and shade trees to reduce energy use

and improve air quality in urban areas. Solar Energy, 70(3), 295–310.

https://doi.org/10.1016/S0038-092X(00)00089-X

Banks, J. L. (n.d.). National Emissions from Lawn and Garden Equipment. 15.

Bob Doppelt. (2009, March). Climate Change Preparation for the Upper Willamette River Basin.

https://climatewise.org/projects/798-upper-willamette#Future%20Climate%20Conditions

“Benefits of Urban Trees.” Southern Group of State Foresters,

www.southernforests.org/urban/benefits-of-urban-trees.

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Additional Links & Information

Green reach code

http://ecodes.biz/ecodes_support/free_resources/Oregon/11_Reach/11_ORReach_main.html

Planting guide https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9040.pdf

Oregon Watershed Enhancement Board https://www.oregon.gov/oweb/Pages/index.aspx

Pudding Watershed Council http://www.watershedcouncils.net/puddingriver/

Marion County Soil Water Conservation Planning https://www.marionswcd.net/what-we-

do/conservation-planning/

City of Silverton Water Masterplan (2012)

https://www.silverton.or.us/DocumentCenter/View/3364/Silverton-SWMP---Final--July-2-2012?bidId=