Dynamic Soil Properties and Dynamic Soil Properties and Dynamic Land Uses:Dynamic Land Uses:

The Need for Dynamic Soil The Need for Dynamic Soil InterpretationsInterpretations

Randall J. MilesRandall J. MilesUniversity of MissouriUniversity of Missouri

National Cooperative Soil Survey National National Cooperative Soil Survey National ConferenceConference

Interpretations ForumInterpretations Forum June 5, 2007June 5, 2007

Dynamic Soil PropertiesDynamic Soil Properties

Near-surface soil propertiesNear-surface soil properties

Multiple depth intervalsMultiple depth intervals

Vegetative characteristicsVegetative characteristics

Dynamic Land UsesDynamic Land Uses

More intensive land use patternsMore intensive land use patterns

Use of “marginal” soil/site conditions Use of “marginal” soil/site conditions (places greater emphasis on surface soil (places greater emphasis on surface soil properties)properties)

Non-traditional usesNon-traditional uses

““Socially controlled” land use patternsSocially controlled” land use patterns

Greater engineering controlsGreater engineering controls

This Increase in Intensive This Increase in Intensive Land Use Pressures Land Use Pressures

Can be Termed:Can be Termed:

Dynamic Use-Dependent Dynamic Use-Dependent FactorsFactors

An Example of a Use-An Example of a Use-Dependent Factor is Onsite Dependent Factor is Onsite

Wastewater Treatment SystemsWastewater Treatment Systems

Applications to:Applications to:

Stormwater abatementStormwater abatement

Soil ErosionSoil Erosion

Biosolids ApplicationsBiosolids Applications

Many othersMany others

OWTS Would Use Many of the OWTS Would Use Many of the Following Fundamental Aspects of:Following Fundamental Aspects of:

Temporal distribution of waterTemporal distribution of water

Spatial distribution of waterSpatial distribution of water

Volume distribution of wastewater from the Volume distribution of wastewater from the OWTSOWTS

Wastewater quality with temporal Wastewater quality with temporal distribution of wastewaterdistribution of wastewater

Wastewater Distribution System Wastewater Distribution System FundamentalsFundamentals

Gravity Distribution: Wastewater Goes in Gravity Distribution: Wastewater Goes in and Wastewater goes out: and Wastewater goes out:

“ “Socially Controlled”Socially Controlled”

versusversus

Timed Dosed Distribution: A Defined Timed Dosed Distribution: A Defined Volume of Wastewater Per Time Unit:Volume of Wastewater Per Time Unit:

“ “Engineering Control”Engineering Control”

““Socially Controlled” SystemSocially Controlled” System

Gravity DistributionGravity Distribution

Dictated by use pattern at the timeDictated by use pattern at the time

Provides a diverse flux of water volume Provides a diverse flux of water volume within the system and subsequent soil within the system and subsequent soil receiving environmentreceiving environment

Provides a diverse flux in quality based on Provides a diverse flux in quality based on volume and functional component within volume and functional component within the housing structurethe housing structure

Basic Gravity System ComponentsBasic Gravity System Components

Source

Septictank with or without

effluent screen

Drainfield

Soil

Drop or Distribution

Box

In ground trench

HOURLY VARIATION IN HOURLY VARIATION IN WASTEWATER FLOWWASTEWATER FLOW

Socially Controlled Provides a Socially Controlled Provides a Diversity of Wastewater Quality Diversity of Wastewater Quality

over Timeover Time

Nutrients-N,P, etcNutrients-N,P, etc

Organics Organics

Total Suspended SolidsTotal Suspended Solids

Heavy MetalsHeavy Metals

Bacteria, Pathogens, Viruses Bacteria, Pathogens, Viruses

SLOPE CONSIDERATIONSSLOPE CONSIDERATIONS

Horizontal Flow

1

2 3

NOT TO SCALENOT TO SCALE

NOT TO SCALENOT TO SCALE

NOT TO SCALENOT TO SCALE

NOT TO SCALENOT TO SCALE

NOT TO SCALENOT TO SCALE

Time Dosed Distribution:Time Dosed Distribution:Engineered DistributionEngineered Distribution

Provides time/volume control distribution Provides time/volume control distribution over a 24/7 time frameover a 24/7 time frame

Provides more uniform distribution of Provides more uniform distribution of wastewater quality (integration of wastewater quality (integration of wastewater quality)wastewater quality)

Provides aeration and resting of soil Provides aeration and resting of soil absorption treatment system absorption treatment system

Pressure manifold to gravity or Pressure manifold to gravity or pressurepressure

Source

Septic Tank with effluent

screen

Drainfield

Soil

PumpTank

Press

ure

man

ifold

NOT TO SCALENOT TO SCALE

Drip Distribution PrinciplesDrip Distribution Principles

A method of wastewater distribution A method of wastewater distribution over a large area as uniformly as over a large area as uniformly as possible shallowlypossible shallowly

Similar to drip irrigation for plants but Similar to drip irrigation for plants but need to disperse the effluent all the need to disperse the effluent all the time.time.

Most uniform method of distributionMost uniform method of distribution

Drip Distribution SystemDrip Distribution System

Summit

Drainage way

Side or back slope Shoulder

Foot slopeToe slope

13

42

5

HYDROLOGIC CYCLEHYDROLOGIC CYCLE

Impermeable Layer

Ground Water

Slow Moving

Lateral FlowSlowly Permeable layer

StreamWater Table

Septic System

Wastewater Input Runoff

Infiltration

Precipitation

Evapotranspiration

Linear Loading RateLateral movementLateral movement

Overall system issueOverall system issue

Controlled by “smallest window”Controlled by “smallest window”

Related to:Related to:– Over all lengthOver all length– Over all [Compounding] flowOver all [Compounding] flow

Dynamic Interpretations for Dynamic Interpretations for Dynamic Use-Dependent FactorsDynamic Use-Dependent Factors

Need fundamental spatial distribution of Need fundamental spatial distribution of water movement in the soil landscapewater movement in the soil landscape

Need fundamental temporal distribution fo Need fundamental temporal distribution fo water movement in the soil landscapewater movement in the soil landscape

Socially controlled versus Engineering Socially controlled versus Engineering Controlled distributionControlled distribution

Need water quality parametersNeed water quality parameters

Additional Pressure for DynamicAdditional Pressure for DynamicUse-Dependent Interpretations Use-Dependent Interpretations

Many land use applications are likely to evolve Many land use applications are likely to evolve from prescriptive based applications to from prescriptive based applications to performance based applications. An example is performance based applications. An example is the National Onsite Wastewater Recycling the National Onsite Wastewater Recycling Association’s Model CodeAssociation’s Model Code

Applications to many other land uses as a result Applications to many other land uses as a result of greater pressure induced by sprawl plus use of greater pressure induced by sprawl plus use and fluxes of water within the soil landscapeand fluxes of water within the soil landscape