Dynamic Soil Properties and Dynamic Land Uses: The Need for Dynamic Soil Interpretations Randall J. Miles University of Missouri National Cooperative Soil Survey National Conference Interpretations Forum June 5, 2007 June 5, 2007

Dynamic Soil Properties Near-surface soil properties Multiple depth intervals Vegetative characteristics

Dynamic Land Uses More intensive land use patterns Use of “marginal” soil/site conditions (places greater emphasis on surface soil properties) Non-traditional uses “Socially controlled” land use patterns Greater engineering controls

This Increase in Intensive Land Use Pressures Can be Termed: Dynamic Use-Dependent Factors

An Example of a Use- Dependent Factor is Onsite Wastewater Treatment Systems Applications to: Stormwater abatement Soil Erosion Biosolids Applications Many others

OWTS Would Use Many of the Following Fundamental Aspects of: Temporal distribution of water Spatial distribution of water Volume distribution of wastewater from the OWTS Wastewater quality with temporal distribution of wastewater

Wastewater Distribution System Fundamentals Gravity Distribution: Wastewater Goes in and Wastewater goes out: Gravity Distribution: Wastewater Goes in and Wastewater goes out: “Socially Controlled” “Socially Controlled” versus versus Timed Dosed Distribution: A Defined Volume of Wastewater Per Time Unit: Timed Dosed Distribution: A Defined Volume of Wastewater Per Time Unit: “Engineering Control” “Engineering Control”

“Socially Controlled” System Gravity Distribution Dictated by use pattern at the time Provides a diverse flux of water volume within the system and subsequent soil receiving environment Provides a diverse flux in quality based on volume and functional component within the housing structure

Basic Gravity System Components Source Septic tank with or without effluent screen Drainfield Soil Drop or Distribution Box

In ground trench

HOURLY VARIATION IN WASTEWATER FLOW

Socially Controlled Provides a Diversity of Wastewater Quality over Time Nutrients-N,P, etc Organics Total Suspended Solids Heavy Metals Bacteria, Pathogens, Viruses

SLOPE CONSIDERATIONS Horizontal Flow 1 2 3

NOT TO SCALE

Time Dosed Distribution: Engineered Distribution Provides time/volume control distribution over a 24/7 time frame Provides more uniform distribution of wastewater quality (integration of wastewater quality) Provides aeration and resting of soil absorption treatment system

Pressure manifold to gravity or pressure Source Septic Tank with effluent screen Drainfield Soil Pump Tank Pressure manifold

NOT TO SCALE

Drip Distribution Principles A method of wastewater distribution over a large area as uniformly as possible shallowly Similar to drip irrigation for plants but need to disperse the effluent all the time. Most uniform method of distribution

Drip Distribution System

Summit Drainage way Side or back slope Shoulder Foot slope Toe slope

HYDROLOGIC CYCLE

Lateral movement Overall system issue Controlled by “smallest window” Related to: –Over all length –Over all [Compounding] flow

Dynamic Interpretations for Dynamic Use-Dependent Factors Need fundamental spatial distribution of water movement in the soil landscape Need fundamental temporal distribution fo water movement in the soil landscape Socially controlled versus Engineering Controlled distribution Need water quality parameters

Additional Pressure for Dynamic Use-Dependent Interpretations Many land use applications are likely to evolve from prescriptive based applications to performance based applications. An example is the National Onsite Wastewater Recycling Association’s Model Code Applications to many other land uses as a result of greater pressure induced by sprawl plus use and fluxes of water within the soil landscape