Developing State-Specific Interpretations for Conventional Vicki … · 2006-10-26 · Vicki M....
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Introduction What are soil survey interpretations? Soil survey interpretations are models predicting the behavior of soil when managed, and result in a logical statement about that particular land use and the relationship of limiting features. These interpretations use a fuzzy systems approach, which shows the gradation of how true (or how false) an interpretive statement is. Interpretations are a series of rules using soil properties in the USDA-NRCS National Soil Information System (NASIS) database. Current national interpretations for wastewater systems are limited to two types: septic tank absorption fields and sewage lagoons. Pennsylvania has 22 different types of wastewater systems which service the 1.2 million households that use onsite wastewater systems. The Pennsylvania NRCS has developed interpretations for seven conventional and sixteen alternate onsite wastewater systems based on criteria supplied by the Pennsylvania Department of Environmental Protection (PADEP). State-specific interpretations are needed as technology improves our ability to provide interpretive soil information to the public. Developing State-Specific Interpretations for Conventional and Alternative Onsite Wastewater Systems Vicki M. Meyers Robert R. Dobos & Paul R. Finnell USDA-NRCS USDA-NRCS Leesport, Pennsylvania Lincoln, Nebraska Results Completed interpretations can be viewed in a report or through a GIS environment where each onsite wastewater system can be viewed individually. Customized NASIS Report Examples Thematic maps in GIS Using Soil Data Viewer Methods Using the NASIS interpretations generator, onsite wastewater interpretations were developed using criteria in the PADEP regulations for site selection and specific soil limitations for each wastewater system. The soil properties used are: Depth to seasonal high water table Depth to bedrock Slope Percolation rate (used Ksat) Flooding Rock fragments Each property is evaluated using fuzzy parameters. This evaluation example of slope for spray irrigation allows specific breaks to be set that are given in regulations. This particular example shows how slopes dictate type of vegetation where spray irrigation can be placed. This is another example of slope being evaluated by a different graph type. It shows a curve where the fuzzy number is indicated by where the data for the property falls on the curve. Once the sub-rules are created, they are put together into the primary rule for a particular onsite wastewater system with an overall ratings class. After each property has been evaluated, an interpretive sub-rule is created (for each evaluation) where the fuzzy numbers are put into rating classes based on the criteria. The OR operator indicates that the rating will be based on the maximum of the fuzzy ratings for the subrules – in this case, “1 – very limited”. Conclusions Tailored interpretations will provide soil survey customers more accurate guidance for the type of wastewater system that might be permitted on a specific soil type. These particular interpretations are specific to PADEP regulations; however, the criteria can be tailored to any location having similar regulations or guidance. This information will then be available to individual home- owners and representatives of regulatory agencies through the Web Soil Survey at http:// websoilsurvey.nrcs.usda.gov. Different onsite wastewater examples are shown. Any state has the ability, with NASIS, to develop state-specific interpretations that meet the needs of their citizens and government agencies. One future example for Pennsylvania is stormwater management. References Source of Map: Natural Resources Conservation Service Web Soil Survey at http://websoilsurvey.nrcs. usda.gov Coordinate System: UTM Zone 18 Soil Survey Area: Berks County, Pennsylvania Spatial Version of Data: 1 Soil Map Compilation Scale: 1:24000 Example of Drip Irrigation System Example of Sand Mound Bed or Trench System Example of Spray Irrigation System USDA is an equal opportunity provider and employer.
Transcript of Developing State-Specific Interpretations for Conventional Vicki … · 2006-10-26 · Vicki M....
Introduction
What are soil survey interpretations?
Soil survey interpretations are models predicting the behavior of soil when managed, and result in a logical statement about that particular land use and the relationship of limiting features. These interpretations use a fuzzy systems approach, which shows the gradation of how true (or how false) an interpretive statement is. Interpretations are a series of rules using soil properties in the USDA-NRCS National Soil Information System (NASIS) database.
Current national interpretations for wastewater systems are limited to two types: septic tank absorption fields and sewage lagoons. Pennsylvania has 22 different types of wastewater systems which service the 1.2 million households that use onsite wastewater systems.
The Pennsylvania NRCS has developed interpretations for seven conventional and sixteen alternate onsite wastewater systems based on criteria supplied by the Pennsylvania Department of Environmental Protection (PADEP). State-specific interpretations are needed as technology improves our ability to provide interpretive soil information to the public.
Developing State-Specific Interpretations for Conventionaland Alternative Onsite Wastewater Systems
Vicki M. Meyers Robert R. Dobos & Paul R. FinnellUSDA-NRCS USDA-NRCS
Leesport, Pennsylvania Lincoln, Nebraska
Results
Completed interpretations can be viewed in a report or through a GIS environment where each onsite wastewater system can be viewed individually.
Customized NASIS Report Examples Thematic maps in GIS Using Soil Data Viewer
Methods
Using the NASIS interpretations generator, onsite wastewater interpretations were developed using criteria in the PADEP regulations for site selection and specific soil limitations for each wastewater system. The soil properties used are:
Depth to seasonal high watertableDepth to bedrockSlopePercolation rate (used Ksat)FloodingRock fragments
Each property is evaluatedusing fuzzy parameters.
This evaluation example of slope for spray irrigation allows specific breaks to be set that are given in regulations. This particular example shows how slopes dictate type of vegetation where spray irrigation can be placed.
This is another example of slope being evaluated by a different graph type. It shows a curve where the fuzzy number is indicated by where the data for the property falls on the curve.
Once the sub-rules are created, they are put together into the primary rule for a particular onsite wastewater system with an overall ratings class.
After each property has been evaluated, an interpretive sub-rule is created (for each evaluation) where the fuzzy numbers are put into rating classes based on the criteria.
The OR operator indicates that the rating will be based on the maximum of the fuzzy ratings for the subrules – in this case, “1 – very limited”.
Conclusions
Tailored interpretations will provide soil survey customers more accurate guidance for the type of wastewater system that might be permitted on a specific soil type. These particular interpretations are specific to PADEP regulations; however, the criteria can be tailored toany location having similar regulations or guidance. This information will then be available to individual home-owners and representatives of regulatory agencies through the Web Soil Survey at http:// websoilsurvey.nrcs.usda.gov. Different onsite wastewater examples are shown.
Any state has the ability, with NASIS, to develop state-specific interpretations that meet the needs of their citizens and government agencies. One future example for Pennsylvania is stormwater management.
References
Source of Map:Natural Resources Conservation Service Web Soil Survey at http://websoilsurvey.nrcs.usda.gov
Coordinate System:UTM Zone 18
Soil Survey Area:Berks County, Pennsylvania
Spatial Version of Data:1
Soil Map Compilation Scale:1:24000
Example of Drip Irrigation System Example of Sand Mound Bed or Trench System Example of Spray Irrigation System
USDA is an equal opportunityprovider and employer.
