““Tree roots are Tree roots are coming to the coming to the

forefront as the forefront as the major cause of major cause of sewer spills”sewer spills”

“So, how do roots grow?”

How Roots GrowHow Roots Grow

Roots provide structural support and Roots provide structural support and nutrition to the treenutrition to the tree

Root growth is similar to tree growth Root growth is similar to tree growth except that roots grow more irregular except that roots grow more irregular and tend to be oval as opposed to and tend to be oval as opposed to circularcircular

Roots grow in length and in diameterRoots grow in length and in diameter Palm roots are the exceptionPalm roots are the exception

– Palm roots grow in length but not in Palm roots grow in length but not in diameter resembling spaghettidiameter resembling spaghetti

How Roots GrowHow Roots Grow

Typically about 85% Typically about 85% of a tree’s roots are of a tree’s roots are within the top 2 within the top 2 feet of soilfeet of soil

To successfully To successfully grow roots need grow roots need moisture, nutrients, moisture, nutrients, and oxygenand oxygen

Tap roots can grow Tap roots can grow deep into the soildeep into the soil

How Roots GrowHow Roots Grow Most of the substantial Most of the substantial

tree roots stay within tree roots stay within the drip linethe drip line

Feeder roots travel 2 to Feeder roots travel 2 to 10 times the diameter 10 times the diameter of the drip lineof the drip line

Some aggressive root Some aggressive root systems can grow out systems can grow out 100 feet or more from 100 feet or more from the treethe tree

How Roots Grow• Different species of trees vary

in how aggressive their root systems are

• Some roots systems grow all year round while others have two growing seasons per year

• Length of the growing period and the amount of growth is effected by temperature, amount of daylight, water, and soil conditions

• Young trees have greater root grow during their growing season than older trees

Roots And SewersRoots And Sewers

Veil type root structures occur in Veil type root structures occur in pipes with a steady flowpipes with a steady flow– Enter from the top or sides of the pipe Enter from the top or sides of the pipe

and hang down like a curtainand hang down like a curtain– Drag along the surface of the water Drag along the surface of the water

extracting moisture and nutrientsextracting moisture and nutrients– Collect grease and debris within their Collect grease and debris within their

structure causing blockagesstructure causing blockages– Seldom grow below the water line Seldom grow below the water line

Roots And SewersRoots And Sewers Tail root structures grow in sewers Tail root structures grow in sewers

with low or intermittent flowswith low or intermittent flows– Appearance is similar to a horse’s tailAppearance is similar to a horse’s tail– Enter the pipe from the top, sides or Enter the pipe from the top, sides or

bottombottom– Grow within the pipe in the direction Grow within the pipe in the direction

of flow eventually filling the pipeof flow eventually filling the pipe– Can extend in what appears as a solid Can extend in what appears as a solid

mass for 20 or more feet within the mass for 20 or more feet within the pipepipe

“Sewers make the

perfect gift for roaming tree roots!”

Roots And SewersRoots And Sewers Roots are Roots are

opportunisticopportunistic Sewers offer Sewers offer

moisture, nutrients moisture, nutrients and oxygen (kind and oxygen (kind of a root heaven!)of a root heaven!)

Sewers provide Sewers provide roots a clear roots a clear growth pathgrowth path

“How do the roots get in the sewers?”

Roots And SewersRoots And Sewers

Through pipe defectsThrough pipe defects(Mains and Laterals)(Mains and Laterals)

Roots And SewersRoots And Sewers

Poor installation is a major cause of defectsPoor installation is a major cause of defects– Bad pipe beddingBad pipe bedding– Poor backfilling and compactionPoor backfilling and compaction

Roots are drawn to leaky sewersRoots are drawn to leaky sewers Roots will travel along a sewer line to find a Roots will travel along a sewer line to find a

defect to provide an entry pointdefect to provide an entry point Aggressive root systems will grow along a Aggressive root systems will grow along a

sewer line exerting pressure to dislodge a sewer line exerting pressure to dislodge a pipe joint or crack the pipe to gain entrypipe joint or crack the pipe to gain entry

Roots And SewersRoots And Sewers

Small feeder roots or hair roots can Small feeder roots or hair roots can enter through the smallest of cracks or enter through the smallest of cracks or defectsdefects

The sewer provides the perfect The sewer provides the perfect environment for these small roots to environment for these small roots to branch out and form root ballsbranch out and form root balls

As the feeder roots grow their diameter As the feeder roots grow their diameter increases putting additional pressure on increases putting additional pressure on the pipe defect they enteredthe pipe defect they entered

Roots And SewersRoots And Sewers

Small roots become large root ballsSmall roots become large root balls

““So How So How Do You Do You

Get Rid of Get Rid of Dem Dem

Roots?”Roots?”

Roots And SewersRoots And Sewers Having an effective maintenance Having an effective maintenance

program that includes a root programprogram that includes a root program– Regular routine line cleaningRegular routine line cleaning– Utilizing the proper cleaning equipment Utilizing the proper cleaning equipment

(mechanical and/or chemical) for pipe type, (mechanical and/or chemical) for pipe type, size and level of root intrusionsize and level of root intrusion

– Scheduled and spot CCTV inspections to Scheduled and spot CCTV inspections to verify line cleaning effortsverify line cleaning efforts

– Become aware of the types of trees Become aware of the types of trees growing along your collection lines and growing along your collection lines and private laterals and how they growprivate laterals and how they grow

Types of Root ControlTypes of Root Control

MechanicalMechanicalChemicalChemical

Mechanical Root ControlMechanical Root Control

Achieves instant root removalAchieves instant root removal Remediates root caused blockagesRemediates root caused blockages Types of mechanical root controlTypes of mechanical root control

– Rodding MachineRodding Machine – good on lines up to 12 – good on lines up to 12 inch diameterinch diameter

– Jetters or FlushersJetters or Flushers – use cutter blades or – use cutter blades or chains rotated by water pressure to cut chains rotated by water pressure to cut rootsroots

– Bucket MachinesBucket Machines – use scrapers designed – use scrapers designed to cut roots – best for large diameter sewersto cut roots – best for large diameter sewers

Mechanical Root ControlMechanical Root Control Mechanical root cutters commonly Mechanical root cutters commonly

become stuck sometimes requiring become stuck sometimes requiring digging up the pipe to remove themdigging up the pipe to remove them

Cutting roots produces Cutting roots produces abscisic acidabscisic acid that hastens and thickens regrowththat hastens and thickens regrowth

Frequency of re-cleaning is based upon Frequency of re-cleaning is based upon several factorsseveral factors– Number of lateralsNumber of laterals– Type and number of trees and root Type and number of trees and root

structuresstructures– Pipe conditionPipe condition– weatherweather

Mechanical Root Control

Examples of mechanical root removal tools

Chemical Root ControlChemical Root Control Use of chemicals is not instantaneous Use of chemicals is not instantaneous

and does not remediate root blockagesand does not remediate root blockages HerbicidesHerbicides

– Contact herbicides kill roots upon contactContact herbicides kill roots upon contact– Systemic herbicides are absorbed into the Systemic herbicides are absorbed into the

root and travel throughout the plantroot and travel throughout the plant– Either type of herbicide will kill the root but Either type of herbicide will kill the root but

it may take weeks, months or even years for it may take weeks, months or even years for the root to decay and break offthe root to decay and break off

Chemical Root ControlChemical Root Control

Many chemicals such as bensulide, Many chemicals such as bensulide, dichlobenil, dinoseb, endothall, metam-dichlobenil, dinoseb, endothall, metam-sodium, paraquat, trifluralin, 2, 4-D, 2, 4, 5-sodium, paraquat, trifluralin, 2, 4-D, 2, 4, 5-T, copper sulfate, and chlorthiamid have T, copper sulfate, and chlorthiamid have been used for root control. Also, acid and been used for root control. Also, acid and basic compounds such as sulfamic or basic compounds such as sulfamic or sulfuric acid and sodium or potassium sulfuric acid and sodium or potassium hydroxide are commonly used as hydroxide are commonly used as pour pour down down products in residential settings. products in residential settings. Local regulations may prohibit using some Local regulations may prohibit using some chemicals.chemicals.

Chemical Root ControlChemical Root Control Application of chemical root controlApplication of chemical root control

– Pour DownPour Down – used primarily by plumbers or – used primarily by plumbers or homeowners for laterals by pouring homeowners for laterals by pouring chemical down a toilet or cleanoutchemical down a toilet or cleanout

– FoamFoam – pipe is injected with a dense foam – pipe is injected with a dense foam that clings to the pipe walls and rootsthat clings to the pipe walls and roots

– SpraySpray – normally used on larger lines with – normally used on larger lines with good flows where filling the line with foam is good flows where filling the line with foam is to costly or impracticalto costly or impractical

De-greasers are commonly added to De-greasers are commonly added to breakdown grease that has collected on breakdown grease that has collected on the rootsthe roots

Which is best?Which is best? Most experts feel that a combination of Most experts feel that a combination of

mechanical and chemical root control is mechanical and chemical root control is the most effective means to control the most effective means to control rootsroots

Mechanically remove the roots followed Mechanically remove the roots followed by applying chemical herbicidesby applying chemical herbicides– Herbicides are most effective if applied Herbicides are most effective if applied

immediately after cuttingimmediately after cutting– Wait for 6 to 8 weeks for the abscisic acid to Wait for 6 to 8 weeks for the abscisic acid to

dissipate before applying herbicides dissipate before applying herbicides – Effectiveness varies from system to systemEffectiveness varies from system to system

“What about

severe root problems?”

Severe Root ProblemsSevere Root Problems

Remove the offending treesRemove the offending trees Dig and properly replace defective pipe Dig and properly replace defective pipe

with a pipe that uses welded joints or with a pipe that uses welded joints or joints that will not easily crack or joints that will not easily crack or separateseparate

Reline the pipe including the lateral Reline the pipe including the lateral connections (Top Hat)connections (Top Hat)

Private lateral maintenance ordinance Private lateral maintenance ordinance and/or program (Santa Barbara)and/or program (Santa Barbara)

“So how are you

controlling your

roots?”

Questions?Questions?Comments?Comments?

Thank YouThank YouBob Kreg – Project Manager – Dudek

Rkreg@dudek.com