Changes

Of the standard granular materials in the standard OPSS.MUNI 1010 only '''Granular O''' is recommended as a substitute for [[reservoir aggregate| clear stone]].  

<include only>Of the standard granular materials in the standard OPSS.MUNI 1010 only '''Granular O''' is recommended as a substitute for [[reservoir aggregate| clear stone]].  

{{Textbox|1= Where Granular O is substituted for clear stone in underground reservoir structures, the void ratio used in design calculations shall be '''0.3''' unless laboratory testing proves otherwise.}}

{{Textbox|1= Where Granular O is substituted for clear stone in underground reservoir structures, the void ratio used in design calculations shall be '''0.3''' unless laboratory testing proves otherwise.}}

Examples of BMPs with underground reservoirs include [[Underdrains]], [[infiltration trenches]], [[permeable paving]], [[infiltration chambers]], [[exfiltration trenches]].  

Examples of BMPs with underground reservoirs include [[Underdrains]], [[infiltration trenches]], [[permeable paving]], [[infiltration chambers]], [[exfiltration trenches]].  

All other mixes must be avoided for free drainage or storage as they are permitted to contain a higher enough proportion of fines to reduce permeability below 50 mm/hr.   

All other mixes must be avoided for free drainage or storage as they are permitted to contain a higher enough proportion of fines to reduce permeability below 50 mm/hr.   

 

===Justification===

===Justification===

Permeability (''K'') was estimated from the 10th percentile grain size using the [[Hazen]] formula.   

Permeability (''K'') was estimated from the 10th percentile grain size using the [[Hazen]] formula.   

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