2.4: Stormwater Management

(21 maximum points possible)

Stormwater Management (21 points)

GREEN GLOBES #2.4.1.1 - ANSI #7.4.1.1 Has a civil engineer made a stormwater management report that includes the following?

• The site retains at least the 95th percentile storm volume as per a site water balance assessment. (17 points)
• Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment. (0 points) 
• Neither of the above (0 points) 
• N/A

Assessment Guidance

The site must retain at least the 95th percentile storm volume as per a site water balance assessment, to be included in the stormwater management report.

Not applicable for interior-only projects.

References 

• Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects 2009 
• U.S. Environmental Protection Agency (EPA) National Stormwater Calculator

Recommended Documents 

• Storm water discharge plan 
• Soil boring reports
• Site plans, including all areas of hardscape
• Percolation test results 
• Civil AND/OR landscaping drawings indicating drainage 
• Area rainfall charts

Note: Criterion only visible if 2.4.1.1 is answered with "Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment."

GREEN GLOBES #2.4.1.1.1 - ANSI #7.4.1.1.1 Does the project meet a minimum of 80% Total Suspended Solids (TSS) removal or complies with municipal AND/OR local watershed water quality control targets?

• Yes (3 points)
• No (0 points)

Assessment Guidance

The project must meet whichever is more stringent: a minimum of 80% Total Suspended Solids (TSS) removal or complies with municipal AND/OR local watershed water quality control targets.

Note: Criterion only visible if 2.4.1.1 is answered with "Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment."

GREEN GLOBES #2.4.1.1.2 - ANSI #7.4.1.1.2 Is there 50% annual average total phosphorus (TP) removal assuming typical pollutant concentrations in urban runoff?

• Yes (1 point)
• No (0 points)

Note: Criterion only visible if 2.4.1.1 is answered with "Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment."

GREEN GLOBES #2.4.1.1.3 - ANSI #7.4.1.1.3 Is there a target removal of alkalinity below 10 mg CaCO3/L

• Yes (1 point)
• No (0 point)

Assessment Guidance

Infiltration is not to be used as a treatment method if the site is located within 0.25 mi (0.4 km) of a lake or wetland.

Note: Criterion only visible if 2.4.1.1 is answered with "Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment."

GREEN GLOBES #2.4.1.1.4 - ANSI #7.4.1.1.3 Is there a target removal for nitrate + nitrite reduction of 40%?

• Yes (1 point)
• No (0 point)

Note: Criterion only visible if 2.4.1.1 is answered with "Yes, but the site does NOT retain at least the 95th percentile storm volume as per a site water balance assessment."

GREEN GLOBES #2.4.1.1.5 - ANSI #7.4.1.1.3 Is there a target removal of pH below 6.5?

• Yes (1 point)
• No (0 point)

GREEN GLOBES #2.4.1.2 - ANSI #7.4.1.2 Are hardscapes and structures located 100 ft. (30.5 m) or more from a natural body of water or natural waterway on or adjacent to the site?

• Yes (4 points)
• No (0 points)
• N/A

Assessment Guidance

Hardscapes and structures exclude pervious walkways 48 in. (121.9 cm) or less in width. Document the distance on the site plan. Water bodies and waterways include: 

• Oceans; 
• Lakes; 
• Rivers; 
• Streams; 
• Estuaries; 
• Bays; 
• Wetlands; 
• Springs, or seeps; 
• Ravines; 
• Arroyos; AND/OR 
• Canyons.

Waterways may be intermittently dry provided they define channeled flow of water when wet.

Not applicable where the body of water is a retention pond or constructed wetland, or is a constructed feature that receives all stormwater runoff.

Recommended Documents 

• Soil boring reports 
• Site plans, including all areas of hardscape
• Civil AND/OR landscaping drawings indicating drainage 
• Area rainfall charts

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