Changes

===Planning considerations===

===Planning considerations===

<h4>Space</h4>

<h4>Space</h4>  

For optimal performance bioretention facilities should receive runoff from between 5 to 20 times their own surface area. In the conceptual design stage it is recommended to set aside approximately 10 - 20 % of a catchment area to the bioretention facility. Bioretention cell(s) work best when distributed so that no one facility receives runoff from more than 0.8 Ha. Although, there is a trade off to be considered regarding distributed collection and treatment against ease of maintenance.  

<p>For optimal performance bioretention facilities should receive runoff from between 5 to 20 times their own surface area. In the conceptual design stage it is recommended to set aside approximately 10 - 20 % of a catchment area to the bioretention facility. Bioretention cell(s) work best when distributed so that no one facility receives runoff from more than 0.8 Ha. Although, there is a trade off to be considered regarding distributed collection and treatment against ease of maintenance. </p>

<h4blue>Infiltration</h4blue>

<h4blue>Infiltration</h4blue>

Some form of stormwater landscaping (bioretention) can be fitted into most spaces. One of the key decisions is whether to infiltrate all of some of the collected water into the native soil. Although there are some [[Infiltration#Constraints|constraints]] to infiltrating water, it is preferable to do so where possible. [[Bioretention:_Partial_infiltration|Partial infiltration]] facilities are a popular choice over 'tight' soils (infiltration ≤ 15 mm/hr).  

<p>Some form of stormwater landscaping (bioretention) can be fitted into most spaces. One of the key decisions is whether to infiltrate all of some of the collected water into the native soil. Although there are some [[Infiltration#Constraints|constraints]] to infiltrating water, it is preferable to do so where possible. [[Bioretention:_Partial_infiltration|Partial infiltration]] facilities are a popular choice over 'tight' soils (infiltration ≤ 15 mm/hr). </p>

{{:Bioretention: Variations}}

{{:Bioretention: Variations}}

<h4>Inlets and pretreatment options</h4>

<h4>Inlets and pretreatment options</h4> Options for pretreatment include:

Options for pretreatment include:

[[Gravel diaphragm]] for sheet flow  

    <li>A [[gravel diaphragm]] for sheet flow </li>

[[Vegetated filter strips]] for sheet flow

    <li>[[Vegetated filter strips]] for sheet flow </li>

[[Oil and grit separators]] for concentrated underground flow

    <li>An [[Oil and grit separators|oild and grit separator]] for concentrated underground flow </li>

<h4>Overflow routing</h4>

<h4>Overflow routing</h4>  

{{:Bioretention: Routing}}

{{:Bioretention: Routing}}

<h4>Design for maintenance</h4>

<h4>Design for maintenance</h4>

 

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