Thursday, October 28, 2021

Updates from October 2021

(Source: E&S Resources Library on PADEP Website)

DEP PCSM Spreadsheet was updated to Version 1.9 as of October 2021:

"1) Modified dropdown list for Infiltration Period (Volume Worksheet, Structural BMP Volume Credits table) to eliminate hours 1-11 (i.e., the minimum Infiltration Period must be 12 hours).  

2) Updated median outflow concentrations (MOCs) for structural BMPs based on the latest analysis of literature data."

As a reminder, the DEP PCSM Spreadsheet Instructions states: "In general, DEP/CCD will accept older versions of the spreadsheet no more than 6 months following the revision date of the spreadsheet. DEP/CCD also reserves the right to request completion of the latest version of the spreadsheet for any project."

Here is an independent analysis of how the MOCs changed. The lower the MOC, the better the water quality treatment. Therefore, if the MOC was reduced, the new value is green, and if the MOC was increased, the new value is red. 

BMP

TSS MOC

(mg/L)

TP MOC

(mg/L)

TN MOC

(mg/L)

Porous Pavement w/Infiltration Bed

26 22

0.11 0.1

1.19 2.38

Infiltration Basin

10

0.24

1.04 0.96

Infiltration Bed

24.3 22

0.19 0.1

1.19 2.38

Infiltration Trench

24.3 22

0.19 0.1

1.19 2.38

Rain Garden / Bioretention

10

0.24

1.04 0.96

Dry Well / Seepage Pit

24.3 22

0.19 0.1

1.19 2.38

Constructed Filter

9

0.09

1.05

Vegetated Swale

24 13.7

0.2 0.18

0.85 0.63

Vegetated Filter Strip

19 23

0.17 0.23

1.13 1.27

Infiltration Berm & Retentive Grading

24 10

0.2 0.24

0.85 0.96

Vegetated Roof

19 23

0.17 0.23

1.13 1.27

Capture and Reuse

N/A

N/A

N/A

Constructed Wetland

12 14

0.1 0.12

1.31 1.37

Wet Pond / Retention Basin

11.7 12

0.09 0.12

1.2

Dry Extended Detention Basin

24.3 22

0.19

1.19 1.22

Water Quality Filters & Hydrodynamic Devices

9 39

0.09 0.18

1.05 2.21

Floodplain Restoration

10 24

0.24 0.18

1.04 1.45

Soil Amendment

19 23

0.17 0.23

1.13 1.27

Riparian Buffer

10 23

0.24 0.23

1.04 1.27

DEP PCSM Spreadsheet Instructions was updated as of October 18, 2021:

"Modified the description for Infiltration Period (Volume Worksheet, Structural BMP Volume Credits table) and NOTE 33 to reflect a change in the PCSM Spreadsheet that a minimum of 12 hours must be selected to represent infiltration that is occurring during a storm event. In addition, the PCSM Spreadsheet has been modified to include updates to Median Outflow Concentrations (MOCs) for structural BMPs based on the latest analysis of literature data."

Alternative E&S and PCSM BMPs was updated to Version 2.1 on October 26, 2021:

"Added Trenchless Curved Silt Fence as an approved alternative E&S BMP"

Friday, October 1, 2021

Updates from September 2021

(Source: E&S Resources Library on PADEP Website)

Alternative E&S and PCSM BMPs was updated to Version 2.0 on September 16, 2021:

"Added corn stover as a partial filler material in filter sock and rice hulls as a primary filler in filter socks as approved alternative E&S BMPs."