green from the ground up - managing riparian buffers

8/9/2019 Green From the Ground Up - Managing Riparian Buffers

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GREENrom the Ground UpNature-friendly design practices for land-savvy developers

Capitalizeon yournaturalassets

Riparian buffers the plantsand trees next to a streamWhat are riparian buers?

Riparian buers are the plants ound along the banks o rivers and streams that provide

wildlie habitat and protect watershed health. They help cool and clean the water by

absorbing runo beore it enters our streams and rivers. When located in urban areas,riparian buers are oten damaged or built on. The natural landscape is replaced with hard

suraces such as driveways, roos and parking lots. When stormwater runo sweeps across

these suraces, it picks up pollutants and debris, washing them directly into our waterways.

Riparian buers act like a sponge, absorbing contaminants and sediment carried by storm-

water runo. A riparian buer dense with trees and shrubs is most eective. Contaminants

like chemicals, ertilizers, oil and eroded soil directly entering our waterways negatively

impact water quality, human health and sh and wildlie habitat.

Planting a riparian buer with trees and shrubs is an easy way to help prevent the negative

eects o polluted stormwater runo. A healthy riparian buer benets you, your employ-

ees, your customers and the environment.

his fact sheet is one

f a series on nature-

riendly development

ractices created by Metro

hrough its Nature in

eighborhoods initiative.

ature-friendly develop-

ment practices minimize

he impact ofdevelopment

n natural resources, andan help developers save

money and add value to

heir properties.

Metros Nature in

eighborhoods initiative

a long-term effort to

onserve and restore

ature throughout the

rban area and ensure

hat every citizen in the

egion has access to

ature.

iparian vegetation on Clearreek in the Clackamasatershed helps protect theream system rom the eects stormwater runo. www.oregonmetro.gov/nature

Keep nature in neighborhoods


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An invasive weed, Scotch broom taking over astretch along the Clackamas River.

Economic Benefts

Increases property

values by enhancing the

aesthetic appeal o your

landscape

Shades buildings and

homes with tree cover,

reducing cooling costs

Attracts shoppers andvisitors to business

districts

Saves money spent on

pesticides and ertilizers

Saves time spent on

property maintenance

Minimizes costs

associated with repairing

problems caused by

stream bank erosion

Environmental

Benefts Lowers stream

temperatures by creating

shade cover

Stabilizes stream banks

by reducing erosion

Slows runo and lters

out pollutants and

sediment beore they

enter local waterways

Osets carbon dioxide

emissions

Reduces the likelihood

o fooding and food

damage

Reduces noise pollution

by creating a noise

barrier

Step one: Choosing the right plant or the right location

Native plants are the best choice or eective riparian buers. They are adapted to localweather patterns and soil types and are pest resistant, thereby reducing watering and mainte-nance costs. Beore purchasing native plants, assess the habitat conditions o your site. Eachnative plant has particular requirements. For example, Oregon white oak is ideally suited tosunny, dry conditions. Once you have perormed your assessment, consult your local nurseryor internet resources to help you identiy the native plants that grow best at your site. Typi-cally, a balanced mix o trees, shrubs and ground cover plants work in any area.

When assessing the habitat conditions here are a ew questions to ask:

What is the sun exposure o the site? (Is it sunny, partially sunny or shaded?)

What are the soil conditions? (Is it clay-like, rocky, sandy or rich black humus?)

How wet is your soil? (Does the area food annually or is it seasonally dry?)

How much room is there or your plant to grow? (Both height and width.)

What kind o native vegetation already exists at the site? (Take a cue rom plants alreadygrowing well in the area.)

How steep is the location? (Is it fat with poor drainage or steeply sloped?)

How close is the planting area to the waterway? (Next to the stream or upslope?)

Has the soil on-site been disturbed or altered rom its original state? (I so, compensate

by choosing disturbance-tolerant plants. Depending on your moisture levels, tall Oregongrape, Oregon ash, Oregon white oak, thimbleberry and nootka rose are good choices.)

Step two: How to prepare thesite protect your investment

Good site preparation is essential to help yournew native plants survive and grow. Invasivespecies are weeds that grow aggressively,out-compete native plants and eventually takeover. Examples o common invasive speciesinclude: Himalayan blackberry, English ivy,Scotch broom, alse brome, butterfy bush,

Japanese knotweed and reed canarygrass.Remove invasives beore planting your nativeplants to protect your investment. They canbe controlled manually with persistence, mo-tivation and continued monitoring. Herbicidesshould not be used near waterways. Land-scape abric, hand pulling, digging, applyingmulch, mowing and planting native vegetation are some o the ways you can control inva-sives. It is important to research which methods work best or the invasives on your property.For example, the methods you use to control Japanese knotweed would not be the same orEnglish Ivy.

Step three: How to plant correctly

In the Pacic Northwest, the best time to plant is all or winter during the rainy season. How-ever, in zone 1, it is best to plant stream banks in the spring and irrigate or the rst year. Fallplantings in zone 1 may be inundated or too long to become established or may be carriedaway by high water i not well-rooted. To determine appropriate elevation, reerence whereplants are already growing directly upstream and downstream o your site. Follow these stepswhen planting. Prepare the site by scraping away invasive weeds in a 2-oot wide circle around the plant-

ing area. Dig a hole two to three times bigger than the root ball. (For plants in 1-gallon containers,

the hole should be 10-12 inches wide.) Remove the plant rom the container and gently loosen the root ball.


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Zone 1 includes the stream channel andstream banks and foods at least part oevery winter. The soil is oten rocky andclay-like. Plants in this zone should be foodtolerant.

Douglasr Westernhemlock Oregonoak swordfern thimbleberry commonsnowberry

Zone 3 includes the upper terrace anduplands located next to the streambank.Plants that thrive in this area are those thatare drought tolerant but do not toleratefooding.

Zone 2 includes the upper banks and food-plain. The soil is less moist than Zone 1.Plants in this zone should be medium foodtolerant.

Pacicninebark salmonberry snowberry swamprose spiraea Westernredcedar Oregonash redalder-typicallyalongstreams blackcottonwood-typicallyalongrivers

red-osierdogwood Sitkawillow Pacicwilloworotherwetlandwillows salmonberryanddeerfernforforestedareas

with no soil disturbance fruitedbulrushandsloughsedgeforsmall

streams

Zone Description Examples of native vegetation

1

2

3

The table below describes how to identiy the three riparian zones and gives

examples o native vegetation appropriate or planting by zone.

Flood tolerance decreases

Figure 1: The threeriparian zones. In

general, as you moverom zone 1 to zone3 the soil moistureand food tolerancedecrease.

Soil moisture decreases

Place the plant in the hole in a straight position. Make sure the hole is deep enough.Shallow holes oten expose the roots to air and reduce survival. Digging a hole too deepcan smother plants.

When burying the root ball, pack the soil around the plant rmly, taking care not tocompact the soil too much or crush the roots. Fill in the hole by slowly adding soil aroundthe roots and lightly tamping down the soil to remove air pockets.

Ater the new plant is buried in the ground, mulch with grass clippings, shredded bark,compost or manure 2-3 inches deep. Take care that the mulch stays 2 inches away romthe plant stem. Mulch will help minimize weeding and watering and help your plantsurvive.

In general, the ideal spacing between smaller trees and shrubs is 5-10 eet. For larger trees,the ideal spacing between plants is 10-15 eet.


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REI volunteer plants a big-lea maple in the riparian area oClear Creek in the Clackamas River watershed.

BoskyDellNativesisalocalnurserywithmorethan

300 dierent types o native plants available or sale.

LocatedinWestLinn,thenurseryneighborsFields

Creek,atributaryofthelowerTualatinRiver.Fields

Creek is home to steelhead, cutthroat trout and red-

leggedfrogs.TheportionofFieldsCreekthatruns

throughBoskyDellNativeswasoncechokedwith

morning glory, Himalayan blackberry, English laurel,

English ivy and Japanese knotweed.

BoskyDell,alongwithnumerouslocalvolunteers,

has worked hard to manually remove these invasive

species and restore a healthy riparian buer by

planting more than 5,000 native shrubs and trees.

Vine maple, red fowering currant, sedge, red-osier

dogwood, trillium, sword ern, and common camas

nowblankettheedgesofFieldsCreek,providing

wildlie habitat, shade, and erosion control.

According to the owner, the most dicult part o this project is managing the invasive weeds

and removing them when they resurace.

TolearnaboutvolunteeropportunitiesatBoskyDellNatives,visitwww.boskydellnatives.com.

Example project: Bosky Dell Natives

Step our: Maintenance

Once your native plant is in the ground, be sure tokeep it well watered, especially in the rst ew weeksater planting. Water slowly, allowing the water tosoak into the soil. For small seedlings, approximately1-2 gallons o water is needed per plant each time youwater. Let the soil almost dry out between soakings,watering once every two weeks during the summer. I

you notice that the leaves are wilting or that the soil iscaked and cracking, then you need to water. Ater oneor two growing seasons, many native plants requirelittle or no watering. Make sure you continuallyremove invasive weeds until the natives ully establish.

For more inormationFor more inormation about riparian corridor restoration, contact the Clackamas RiverBasin Council at www.clackamasriver.org or call 503-558-0550. Learn more about nature-riendly development practices or Metros Nature in Neighborhoods initiative. Visitwww.oregonmetro.gov/nature, send e-mail to [email protected] or call503-797-1588.

Local nurseries that sell native plantsFind locations in your area that carry native plants. Visit www.plantnative.org orwww.cleanwaterservices.org.

For more inormation onnature-riendly developmentpractices or Metros Naturein Neighborhoods initiative,visit www.oregonmetro.gov/nature, send e-mail [email protected] orcall 503-797-1555.

GREENrom the Ground UpSeminars for land-savvy developers

Clean air and clean water donot stop at city limits or countylines. Neither does the needor jobs, a thriving economyand good transportation choic-es or people and businesses inour region. Voters have askedMetro to help with the chal-

lenges that cross those linesand aect the 25 cities andthree counties in the Portlandmetropolitan area.

A regional approach simplymakes sense when it comes toprotecting open space, caringor parks, planning or thebest use o land, managinggarbage disposal and increas-ing recycling. Metro overseesworld-class acilities such asthe Oregon Zoo, which con-tributes to conservation andeducation, and the OregonConvention Center, which

benets the regions economy.

Your Metro representativesMetro Council PresidentDavidBragdon

Metro CouncilorsRodPark,District1CarlottaCollette,District2CarlHosticka,District3KathrynHarrington,District4RexBurkholder,District5RobertLiberty,District6AuditorSuzanneFlynn

Funding or this and otheract sheets in the Nature inNeigh-borhoods nature-

riendly development prac-tices series is provided inpart by an Oregon Depart-ment of EnvironmentalQuality Section 319 Grant.

Content and design contri-butions pro-vided by theClackamasRiver BasinCouncil.

green from the ground up - managing riparian buffers

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