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Line 23: − ====Background Evaluation====+ Line 44:
Line 44: − ====Test Pit or Soil Boring Observations====+ Line 67:
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→Four Step Process
'''Soil classification by texture, and then calculating permeability is not an acceptable alternative to measuring infiltration rate in the field.'''
'''Soil classification by texture, and then calculating permeability is not an acceptable alternative to measuring infiltration rate in the field.'''
==Four Step Process==
Soil infiltration testing is a four-step process to obtain the necessary information for stormwater management planning and design. The four steps include:
Soil infiltration testing is a four-step process to obtain the necessary information for stormwater management planning and design. The four steps include:
*Consideration of desired BMP drawdown period.
*Consideration of desired BMP drawdown period.
===Background Evaluation===
[[File:Infiltration_Testing_2.jpeg|thumb|Coring holes for infiltration testing]]
[[File:Infiltration_Testing_2.jpeg|thumb|Coring holes for infiltration testing]]
Prior to performing testing and developing a detailed site plan, existing site conditions should be inventoried and mapped including, but not limited to:
Prior to performing testing and developing a detailed site plan, existing site conditions should be inventoried and mapped including, but not limited to:
*Proposed location of development features (buildings, roads, utilities, etc.).
*Proposed location of development features (buildings, roads, utilities, etc.).
===Test Pit or Soil Boring Observations===
Test pits or soil borings provide information regarding the soil horizons and overall soil conditions both horizontally and vertically in that portion of the site. Multiple observations can be made across a site at a relatively low cost and in a short time period.
Test pits or soil borings provide information regarding the soil horizons and overall soil conditions both horizontally and vertically in that portion of the site. Multiple observations can be made across a site at a relatively low cost and in a short time period.
*For sites with multiple infiltration BMPs, each with footprint surface areas less than 50 square metres, a minimum of one test pit is required and one soil boring per infiltration BMP location is recommended.
*For sites with multiple infiltration BMPs, each with footprint surface areas less than 50 square metres, a minimum of one test pit is required and one soil boring per infiltration BMP location is recommended.
===Infiltration Testing===
The preferred testing period is during April and May. If testing is conducted between June 1 and December 1, the soil should be soaked for 24 hours prior, to simulate field saturated conditions.<ref>http://www.extension.umn.edu/environment/housing-technology/moisture-management/how-to-run-a-percolation-test/index.html</ref>
The preferred testing period is during April and May. If testing is conducted between June 1 and December 1, the soil should be soaked for 24 hours prior, to simulate field saturated conditions.<ref>http://www.extension.umn.edu/environment/housing-technology/moisture-management/how-to-run-a-percolation-test/index.html</ref>
*In sandy soils, where half the depth of water percolates within 30 minutes. Otherwise, calculate the infiltration rate
*In sandy soils, where half the depth of water percolates within 30 minutes. Otherwise, calculate the infiltration rate
==Design Considerations==
{{:Safety correction factors}}
{{:Safety correction factors}}