Tables: Groundwater Recharge¶
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1. Table 6-1: NJGRS/TR-55 and GSR-32 LULC Descriptions¶
| NJGRS/TR-55 LULC Descriptions | GSR-32 LULC Descriptions |
|---|---|
| Brush | Brush |
| Gravel, Dirt | Unvegetated |
| Impervious Areas | Un-landscaped Developed |
| Meadow, Pasture, Grassland or Range | Agricultural – Pasture |
| Open Space | Landscape Open Space |
| Residential 1 to 2 Acre | 1 - 2 Acre Lots |
| Residential 1/2 to 1 Acre | 1/2 - 1 Acre Lots |
| Residential 1/3 to 1/4 Acre | 1/8 - 1/2 Acre Lots |
| Residential 1/8 Acre or Less | 1/8 Acre Lots |
| Row Crop | Agricultural – General |
| Small Grain or Legumes | Agricultural – Cropland, Legume |
| Urban Districts | Landscaped Developed |
| Woods | Woods |
| Woods – Grass Combination | Wooded – General |
Source context and notes
# Groundwater Recharge Source revision: July 2023. Table 6-1: NJGRS/TR-55 and GSR-32 LULC Descriptions | NJGRS/TR-55 LULC Descriptions | GSR-32 LULC Descriptions | | --- | --- | | Brush | Brush | | Gravel, Dirt | Unvegetated | | Impervious Areas | Un-landscaped Developed | | Meadow, Pasture, Grassland or Range | Agricultural – Pasture | | Open Space | Landscape Open Space | | Residential 1 to 2 Acre | 1 - 2 Acre Lots | | Residential 1/2 to 1 Acre | 1/2 - 1 Acre Lots | | Residential 1/3 to 1/4 Acre | 1/8 - 1/2 Acre Lots | | Residential 1/8 Acre or Less | 1/8 Acre Lots | | Row Crop | Agricultural – General | | Small Grain or Legumes | Agricultural – Cropland, Legume | | Urban Districts | Landscaped Developed | | Woods | Woods | | Woods – Grass Combination | Wooded – General | As noted in the NJGRS User's Guide, it is important to specify a site's LULC characteristics as accurately as possible. Therefore, while a 1/4 acre residential site could be specified in the NJGRS by the "Residential 1/3 to 1/4 Acre" LULC description in Table 6-1, it is generally more accurate to divide the site into impervious and pervious areas and specify each as a separate land segment in the NJGRS. For example, at a 1/4 acre residential site with a total area of 10 acres consisting of 40 percent connected impervious and 60 percent grassed surfaces and a single soil series, it would be more appropriate to specify the site's LULC characteristics in the program as a separate 4 acre impervious area land segment and a 6 acre open space land segment. This separation of connected impervious and pervious areas is similar to the technique for computing runoff volume using the NRCS methodology in Chapter 5. It should be noted that the total impervious area for post-developed conditions displayed in Cell M23 of the Annual Recharge worksheet will be based only on those post-developed land segments specified as impervious. When using the above technique, it should be noted that if any impervious areas at a development site are unconnected (see Chapter 5 for complete details and requirements), the area used in the impervious surface designations described above for these unconnected areas should be one half of the actual area. For example, if a site has 3 acres of directly connected impervious surface, but 2 acres of unconnected impervious area, the total impervious area specified in the NJGRS can be $3 + (0.5)(2)$ or 4 acres. This 50 percent reduction in the size of unconnected impervious areas accounts for the runoff re-infiltration that can occur downstream of such areas and is consistent with the runoff computations for such areas contained in TR-55. To keep the total site area correct, the user should remember to specify the "remainder" of the unconnected impervious area as a pervious one with the appropriate soil series and LULC based upon the actual pervious area downstream of the unconnected impervious area.2. Table 2¶
| S S | C D E F I D H I | J | E L M | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | New Jersey Groundwater Recharge Spreadsheet Version 2.0 (November 2003) | Annual Groundwater Recharge Analysis (based on GSR-32) | Project Name: | Sample Project | |||||||
| Select Township ↓ | Average Annual P (in) | Climatic Factor | Description: | This is a test application | |||||||
| MIDDLESEX CO., PERTH AMBOV CITY | 47.0 | 1.53 | Analysis Date: | 09/01/03 | |||||||
| 2 | Pre-Developed Conditions | Post-Developed Conditions | |||||||||
| Land Segment | Area (acres) | TR-SS Land Cover | Soil | Annual Recharge (in) | Annual Recharge (cu/h) | Land Segment | Area (acres) | TR-SS Land Cover | Soil | Annual Recharge (in) | |
| 3 | 1 | 1.4 | Open space | Woodstown | 12.9 | 65,498 | 1 | 1.5 | Imperation areas | Kepsort | 0.0 |
| 4 | 2 | 0.3 | Grand, dirt | Woodstown | 6.0 | 7,536 | 2 | 1.6 | Grand, dirt | Woodstown | 6.9 |
| 5 | 3 | 3.5 | Woods-grass combination | Woodstown | 13.5 | 171,255 | 3 | 3.65 | Open space | Kepsort | 13.4 |
| 6 | 4 | 1.4 | Open space | Kepsort | 13.4 | 68,146 | 4 | 3.65 | Open space | Woodstown | 12.9 |
| 7 | 5 | 0.5 | Grand, dirt | Kepsort | 7.5 | 13,657 | 5 | ||||
| 8 | 6 | 3.3 | Woods-grass combination | Kepsort | 13.0 | 165,963 | 6 | ||||
| 9 | 7 | 7 | |||||||||
| 10 | 8 | 8 | |||||||||
| 11 | 9 | 9 | |||||||||
| 12 | 10 | 10 | |||||||||
| 13 | 11 | 11 | |||||||||
| 14 | 12 | 12 | |||||||||
| 15 | 13 | 13 | |||||||||
| 16 | 14 | 14 | |||||||||
| 17 | 15 | 15 | |||||||||
| 18 | Total = | 10.4 | Total Annual Recharge (in) | Total Annual Recharge (cu/h) | Total = | 10.4 | Total Annual Recharge (in) | ||||
| 21 | 13.0 | 492,054 | Annual Recharge Requirements Calculation : | 10.3 | 308,620 | ||||||
| 22 | % of Pre-Developed Annual Recharge to Preserve = | 100% | Total Imperation Area(cu/h) | 65,340 | |||||||
| 23 | Procedure to fill the Pre-Development and Post-Development Conditions Tables | % of Pre-Developed Annual Recharge to Preserve = | 100% | Total Imperation Area(cu/h) | 65,340 | ||||||
| 24 | For each land segment, first enter the area, then select TR-SS Land Cover, then select Soil. Start from the top of the table | Post-Development Annual Recharge Deficit= 103,435 | (cubic feet) | ||||||||
| 25 | and proceed downward. Don't know blank rows (with A=5) to between your segment entries. Rows with A=5 will not be | Recharge Efficiency Parameters Calculations (area averages) | |||||||||
| 26 | displayed on sand in calculations. For Imperation areas outside of standard line select "Imperation Areas" as the Land Cover. | HWC= 3.94 | (in) | ERWC= 3.94 | (in) | ||||||
| 27 | Soil (gas for Imperation areas are only required if an infiltration facility will be built within these areas. | ERWC = 0.03 | (in) | EDRWC= 0.03 | (in) |
Source context and notes
- BMP Calculations: This worksheet, which resides on the second page of the spreadsheet, is used to design the required size and configuration of one or more groundwater recharge BMPs to satisfy the “Post-Development Annual Recharge Deficit” calculated in the Annual Recharge worksheet. NOTE: Only the above worksheets in the NJ Groundwater Recharge Spreadsheet are for user input. Charts 1 through 3 can be viewed for visual inspection of the results. Other worksheets in the spreadsheet are either for internal calculations or contain the databases used by calculations. The user should refrain from changing anything in these worksheets. # Part 1: Using the Annual Recharge Worksheet Figure 1: Screen Capture Showing the Annual Recharge Worksheet | S S | | C D E F I D H I | | | | | | J | E L M | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 1 | New Jersey Groundwater Recharge Spreadsheet Version 2.0 (November 2003) | Annual Groundwater Recharge Analysis (based on GSR-32) | | | | | | Project Name: | Sample Project | | | | | | Select Township ↓ | Average Annual P (in) | Climatic Factor | | Description: | This is a test application | | | | | | | | | MIDDLESEX CO., PERTH AMBOV CITY | 47.0 | | | | 1.53 | Analysis Date: | 09/01/03 | | | 2 | Pre-Developed Conditions | | | | | Post-Developed Conditions | | | | | | | | Land Segment | Area (acres) | TR-SS Land Cover | Soil | Annual Recharge (in) | Annual Recharge (cu/h) | Land Segment | Area (acres) | TR-SS Land Cover | Soil | Annual Recharge (in) | | 3 | 1 | 1.4 | Open space | Woodstown | 12.9 | 65,498 | 1 | 1.5 | Imperation areas | Kepsort | 0.0 | | 4 | 2 | 0.3 | Grand, dirt | Woodstown | 6.0 | 7,536 | 2 | 1.6 | Grand, dirt | Woodstown | 6.9 | | 5 | 3 | 3.5 | Woods-grass combination | Woodstown | 13.5 | 171,255 | 3 | 3.65 | Open space | Kepsort | 13.4 | | 6 | 4 | 1.4 | Open space | Kepsort | 13.4 | 68,146 | 4 | 3.65 | Open space | Woodstown | 12.9 | | 7 | 5 | 0.5 | Grand, dirt | Kepsort | 7.5 | 13,657 | 5 | | | | | | 8 | 6 | 3.3 | Woods-grass combination | Kepsort | 13.0 | 165,963 | 6 | | | | | | 9 | 7 | | | | | | 7 | | | | | | 10 | 8 | | | | | | 8 | | | | | | 11 | 9 | | | | | | 9 | | | | | | 12 | 10 | | | | | | 10 | | | | | | 13 | 11 | | | | | | 11 | | | | | | 14 | 12 | | | | | | 12 | | | | | | 15 | 13 | | | | | | 13 | | | | | | 16 | 14 | | | | | | 14 | | | | | | 17 | 15 | | | | | | 15 | | | | | | 18 | Total = | 10.4 | | | Total Annual Recharge (in) | Total Annual Recharge (cu/h) | Total = | 10.4 | | | Total Annual Recharge (in) | | 21 | | 13.0 | 492,054 | Annual Recharge Requirements Calculation : | | | 10.3 | 308,620 | | | | | 22 | | | | | % of Pre-Developed Annual Recharge to Preserve = | | 100% | Total Imperation Area(cu/h) | 65,340 | | | | 23 | Procedure to fill the Pre-Development and Post-Development Conditions Tables | | | | | | % of Pre-Developed Annual Recharge to Preserve = | | 100% | Total Imperation Area(cu/h) | 65,340 | | 24 | For each land segment, first enter the area, then select TR-SS Land Cover, then select Soil. Start from the top of the table | | | | | | Post-Development Annual Recharge Deficit= 103,435 | | | | (cubic feet) | | 25 | and proceed downward. Don't know blank rows (with A=5) to between your segment entries. Rows with A=5 will not be | | | | | | Recharge Efficiency Parameters Calculations (area averages) | | | | | | 26 | displayed on sand in calculations. For Imperation areas outside of standard line select "Imperation Areas" as the Land Cover. | | | | | | HWC= 3.94 | (in) | ERWC= 3.94 | (in) | | | 27 | Soil (gas for Imperation areas are only required if an infiltration facility will be built within these areas. | | | | | | ERWC = 0.03 | (in) | EDRWC= 0.03 | (in) | |3. Table 3¶
| 1 | Project Name | Description | Analysis Date | BMP or LID Type | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sample Project | This is a test application | 09/01/03 | |||||||||||||
| Infiltration BMP Input Parameters | Base Zone Water capacity Calculated Parameters | Recharge Design Parameters | |||||||||||||
| 4 | Parameter | Symbol | Value | Unit | Parameter | Symbol | Value | Unit | Parameter | Symbol | Value | Unit | |||
| 5 | BMP Area | ABMP | 4696.0 | sq ft | Empty Portion of RWC under Post-D Natural Recharge | ERWC | 0.93 | n | Inches of Runoff to capture | Gdesign | 0.54 | n | |||
| BMP Effective Depth, this is the design variable | dBMP | 5.2 | n | ERWC Modified to consider dEXC | EDRWC | 0.93 | n | Inches of Rainfall to capture | Pdesign | 0.67 | n | ||||
| Upper level of the BMP surface (negative if above ground) | dBMPu | 5.2 | n | Empty Portion of RWC under Infilt. BMP | RERWC | 0.74 | n | Recharge Provided Avg. over Imp. Area | 19.0 | n | |||||
| 6 | Depth of lower surface of BMP, must be==dBMPu | dEXC | 0.0 | n | Runoff Captured Avg. over Imp. Area | 24.8 | n | ||||||||
| Post-development Land Segment Location of BMP | SegBMP | 0 | unitless | ||||||||||||
| 7 | Solve for ABMP to provide Vdef | Solve for dBMP to provide Vdef | Default Vdef & Rimp | BMP Calculated Size Parameters | CALCULATION CHECK MESSAGES | ||||||||||
| ABMP/Aimp | Area | 0.10 | unitless | Volume Balance=0.08 | |||||||||||
| BMP Volume | VBMP | 2,873 | cu ft | dBMP Check=>0.08 | |||||||||||
| 12 | Parameters from Annual Recharge Worksheet | System Performance Calculated Parameters | dEXC Check=>0.08 | ||||||||||||
| Post-D Deficit Recharge (or desired recharge volume) | Vdef | 103,435 | cu ft | Annual BMP Recharge Volume | 103,435 | cu ft | BMP Location=>Location is selected as distributed or undetermined | ||||||||
| 15 | Post-D Impervious Area (or target Impervious Area) | Aimp | 65,340 | sq ft | Avg BMP Recharge Efficiency | 76.7% | Represents % Infiltration Recharged | OTHER NOTES | |||||||
| 16 | Root Zone Water Capacity | RWC | 3.94 | n | %Rainfall became Runoff | 78.3% | % | Pdesign is accurate only after BMP dimensions are updated to make each column deficit volume. The portion of BMP infiltration prior to filling and the area occupied by BMP are ignored in these calculations. Results are sensitive to dBMP, make sure dBMP selected is small enough for BMP to empty in less than 3 days. For land | |||||||
| 17 | RWC Modified to consider dEXC | DRWC | 3.94 | n | %Runoff infiltrated | 66.2% | % | ||||||||
| 19 | Climatic Factor | C-factor | 1.53 | no units | %Runoff Recharged | 50.8% | % | ||||||||
| 20 | Average Annual P | Pavg | 47.8 | n | %Rainfall Recharged | 39.7% | % | Segment Location of BMP if you select "impervious area." RWC will be minimal but not zero as determined by | |||||||
| 21 | Recharge Requirement over Imp. Area | dr | 19.0 | n | the recharge and a dilution cost save for the Land Cover allowing consideration of stated flow and other losses. |
Source context and notes
NOTE: The Appendix to this guide provides the basic equations and defines the variables used in Recharge Efficiency Parameter Calculations. # Part 2: Using the BMP Calculations Worksheet This worksheet allows the proper sizing of groundwater recharge BMPs to provide the desired or required volume of annual groundwater recharge. Alternatively, it can be used to evaluate the performance of a user specified recharge BMP. As described in Chapter 2, groundwater recharge BMPs can also be referred to as Low Impact Development BMPs (or LID-BMPs), depending on their size and location in the project site. Figure 2: Screen Capture from the BMP Calculations Worksheet | 1 | Project Name | | Description | | | | Analysis Date | | BMP or LID Type | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | Sample Project | | This is a test application | | | | 09/01/03 | | | | | | | | | | | Infiltration BMP Input Parameters | | Base Zone Water capacity Calculated Parameters | | | | Recharge Design Parameters | | | | | | | | | | 4 | Parameter | Symbol | Value | Unit | Parameter | Symbol | Value | Unit | Parameter | Symbol | Value | Unit | | | | | 5 | BMP Area | ABMP | 4696.0 | sq ft | Empty Portion of RWC under Post-D Natural Recharge | ERWC | 0.93 | n | Inches of Runoff to capture | Gdesign | 0.54 | n | | | | | | BMP Effective Depth, this is the design variable | dBMP | 5.2 | n | ERWC Modified to consider dEXC | EDRWC | 0.93 | n | Inches of Rainfall to capture | Pdesign | 0.67 | n | | | | | | Upper level of the BMP surface (negative if above ground) | dBMPu | 5.2 | n | Empty Portion of RWC under Infilt. BMP | RERWC | 0.74 | n | Recharge Provided Avg. over Imp. Area | | 19.0 | n | | | | | 6 | Depth of lower surface of BMP, must be==dBMPu | dEXC | 0.0 | n | | Runoff Captured Avg. over Imp. Area | | 24.8 | n | | | | | | | | | Post-development Land Segment Location of BMP | SegBMP | 0 | unitless | | | | | | | | | | | | | 7 | Solve for ABMP to provide Vdef | Solve for dBMP to provide Vdef | Default Vdef & Rimp | BMP Calculated Size Parameters | | | | CALCULATION CHECK MESSAGES | | | | | | | | | | | | | | ABMP/Aimp | Area | 0.10 | unitless | Volume Balance=0.08 | | | | | | | | | | | | | BMP Volume | VBMP | 2,873 | cu ft | dBMP Check=>0.08 | | | | | | | | 12 | Parameters from Annual Recharge Worksheet | | | System Performance Calculated Parameters | | | | dEXC Check=>0.08 | | | | | | | | | | Post-D Deficit Recharge (or desired recharge volume) | Vdef | 103,435 | cu ft | Annual BMP Recharge Volume | | 103,435 | cu ft | BMP Location=>Location is selected as distributed or undetermined | | | | | | | | 15 | Post-D Impervious Area (or target Impervious Area) | Aimp | 65,340 | sq ft | Avg BMP Recharge Efficiency | | 76.7% | Represents % Infiltration Recharged | OTHER NOTES | | | | | | | | 16 | Root Zone Water Capacity | RWC | 3.94 | n | %Rainfall became Runoff | | 78.3% | % | Pdesign is accurate only after BMP dimensions are updated to make each column deficit volume. The portion of BMP infiltration prior to filling and the area occupied by BMP are ignored in these calculations. Results are sensitive to dBMP, make sure dBMP selected is small enough for BMP to empty in less than 3 days. For land | | | | | | | | 17 | RWC Modified to consider dEXC | DRWC | 3.94 | n | %Runoff infiltrated | | 66.2% | % | | | | | | | | | 19 | Climatic Factor | C-factor | 1.53 | no units | %Runoff Recharged | | 50.8% | % | | | | | | | | | 20 | Average Annual P | Pavg | 47.8 | n | %Rainfall Recharged | | 39.7% | % | Segment Location of BMP if you select "impervious area." RWC will be minimal but not zero as determined by | | | | | | | | 21 | Recharge Requirement over Imp. Area | dr | 19.0 | n | | | | | the recharge and a dilution cost save for the Land Cover allowing consideration of stated flow and other losses. | | | | | | |4. Table 4¶
| Variable | Range of Values, in NJ |
|---|---|
| RWC | 0.3 or 14.35 |
| Gravel, Dirt | 1.18 – 1.83 |
| Impervious Areas | 0.02 or 5.88 |