Changes

==Target groundwater separation==

==Target groundwater separation==

In many areas of Ontario the target separation between the base of an infiltrating LID practice and the water table is 1.0 m.  

In many areas of Ontario the target separation between the base of an infiltrating LID practice and the seasonally water table or bedrock surface elevation is 1.0 m.  

This is to mitigate risks due to short periods of groundwater mounding and potentially unobserved seasonal fluctuations. In areas where a 1.0 m separation cannot be provided, or where conditions dictate that an even greater separation may be warranted, additional discussion and/or analysis specific to the physical characteristics of the site and the proposed design should be completed.  

This is to mitigate risks due to short periods of groundwater mounding and potentially unobserved seasonal fluctuations. Seasonally high water table elevation should be determined through continuous water level monitoring of wells in the vicinity of the proposed infiltration facilities during spring months (March to June), when water levels in shallow aquifers are typically at their peak. In areas where a 1.0 m separation cannot be provided, or where conditions dictate that an even greater separation may be warranted, additional discussion and/or analysis specific to the physical characteristics of the site and the proposed design should be completed.  

The design practitioner is advised to consult with approval agencies to understand their requirements and/or expectations prior to undertaking work, and to complete an appropriate level of analysis to support their conclusion. The requirement for additional investigation and/or documentation supporting a proposed design may be reduced in areas where ≥ 1.0 m separation is anticipated.

The design practitioner is advised to consult with approval agencies to understand their requirements and/or expectations prior to undertaking work, and to complete an appropriate level of analysis to support their conclusion. The detail of investigation and/or documentation supporting a proposed design may be reduced in areas where ≥ 1.0 m separation is anticipated.

Retention of an unsaturated zone beneath the practice :

Retention of an unsaturated zone beneath the practice :

==Groundwater mounding==

==Groundwater mounding==

Groundwater mounding describes the localised raising of the water table beneath infiltration practices. It may be of concern if it affects nearby structures including building foundations.

Groundwater mounding describes the localized raising of the water table beneath infiltration practices. It may be of concern if it affects nearby structures including building foundations.

When you wish to model the extent of groundwater mounding beneath an infiltration facility, use this Tool that incorporates Hantush's derivation (1967).   

When you wish to model the extent of groundwater mounding beneath an infiltration facility, use this Tool that incorporates Hantush's derivation (1967).   

{{Clickable button|[[Media:Hantush.xlsm|Download the Hantush groundwater mounding tool]]}}

{{Clickable button|[[Media:Hantush.xlsm|Download the Hantush groundwater mounding tool]]}}

Note that this is a minor adaptation (metric units and formatting) from the original tool, written and [https://pubs.usgs.gov/sir/2010/5102/ hosted by the USGS].

Note that this is a minor adaptation (metric units and formatting) from the original tool, written and [https://pubs.usgs.gov/sir/2010/5102/ hosted by the USGS].

===Preventing groundwater interaction===

===Preventing groundwater interaction===

Many LID systems rely upon reuse, or evaporation and transpiration instead of infiltration to the ground. If the site cannot support any infiltration, consider  

Many LID systems rely upon reuse, or evaporation and transpiration instead of infiltration to the ground. If the site cannot support any infiltration, consider  

*[[Rainwater harvesting]],  

*[[Rainwater harvesting]],  

*[[Stormwater planters]],  

*[[Stormwater planters]],  

===Other sources of groundwater data===

===Other sources of groundwater data===

*[http://ontariogroundwater.com/ Ontario groundwater]

*[http://ontariogroundwater.com/ Ontario groundwater]

*[https://www.ontario.ca/environment-and-energy/map-provincial-groundwater-monitoring-network Provincial groundwater monitoring network map]

*[https://www.ontario.ca/environment-and-energy/map-provincial-groundwater-monitoring-network Provincial groundwater monitoring network map]

==Beginning an infiltration BMP design?==

==Beginning an infiltration BMP design?==

See [[Design infiltration rates]]

See [[Infiltration: Testing| Infiltration testing]] and [[Design infiltration rates]] pages

==See also==

==See also==