> For the complete documentation index, see [llms.txt](https://help.fielddoc.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.fielddoc.org/resources/models/shoreline-restoration-load-reduction-estimates.md).

# Shoreline Restoration Load Reduction Estimates

The [2019 Shoreline Management Expert Panel Report](https://d18lev1ok5leia.cloudfront.net/chesapeakebay/documents/Final_Shoreline-Management_RPT__APPENDICES_12-18-19.pdf) provides the scientific basis for this model. The Expert Panel developed four protocols for nitrogen, phosphorus, and sediment reduction crediting in shoreline management practices.

A user moves through the following steps to calculate their load reductions. Make sure to take note of which fields are optional and which are required. 

1. **Connect an activity (optional)**

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2Fumjp3ofkbInt5sPKbJOz%2FScreenshot%202026-10-06%20at%204.56.03%E2%80%AFPM.png?alt=media&amp;token=cabd9bae-12d7-4a96-b700-b156b360ebb7" alt="" width="375"><figcaption></figcaption></figure>

2. **Project design completion percentage (optional)** How far along are you with your shoreline management design at the time of entering values into FieldDOc? Do not select the percentage of design completion you anticipate at project start time. Per the expert panel report, as the inputs for shoreline management require engineered specifications, only those proposals that are at least 60% design can use protocols 1, 2, 3, and 4.&#x20;

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2FtMoCVsXuyQgMlesdjehC%2FScreenshot%202026-10-06%20at%204.56.31%E2%80%AFPM.png?alt=media&amp;token=2be9390d-762a-4b8f-bcd2-bfc3ba7651ea" alt="" width="375"><figcaption></figcaption></figure>

3. **Enter length of living shoreline in feet.** This should be the linear feet of proposed shoreline restoration practice.&#x20;

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2FnqnnTTQn4Sg2GK9YnjDl%2FScreenshot%202026-10-06%20at%204.57.08%E2%80%AFPM.png?alt=media&amp;token=1e8b1caf-f738-400b-8884-078c455fd839" alt="" width="375"><figcaption></figcaption></figure>

4. **Enter erosion parameters.** Enter the engineering parameters for erosion-based load reduction calculations.

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2F5mVRiNXYOWH69NTDUuPI%2FScreenshot%202026-10-06%20at%205.05.24%E2%80%AFPM.png?alt=media&amp;token=f815aae9-822b-4f70-ab00-0015f4eb07a6" alt="" width="563"><figcaption></figcaption></figure>

5. **Enter wetland parameters.** Enter concentration values and planted tidal wetland area for denitrification, sedimentation, and marsh Redfield ratio protocol calculations.

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2FDdUF2kXXbpCveYGnWCi7%2FScreenshot%202026-10-06%20at%205.08.21%E2%80%AFPM.png?alt=media&amp;token=3e78983b-6ab3-4430-b498-c074e8f4826e" alt="" width="563"><figcaption></figcaption></figure>

6\. **Estimated sediment and nutrient load reduction.** The system will calculate the estimated nutrient and sediment load reductions as the inputs are added.&#x20;

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2FVQfTto3kElK6WhLCcV6U%2FScreenshot%202026-10-06%20at%207.43.59%E2%80%AFPM.png?alt=media&amp;token=c48e2282-2995-4735-891e-dc0b37cd0782" alt="" width="375"><figcaption></figcaption></figure>

7. **Add label and notes**. Enter a label for this run.

<figure><img src="https://2238918414-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FatQfu0bk7aRHUPp2fz19%2Fuploads%2Fsr6Xy9HwbKVZpUhKbf8g%2FScreenshot%202026-10-06%20at%207.45.55%E2%80%AFPM.png?alt=media&amp;token=1992f6ed-26fd-4a01-b570-392052fb23e9" alt="" width="375"><figcaption></figcaption></figure>

## Protocol 1: Prevented Sediment

Awards credit for shoreline practices that prevent bank erosion and sediment loss. Inputs include shoreline length, bank height, recession rate, soil bulk density, and reduction factors for sand content and bank instability.

```
tss_tons = length * height * recession_rate * bulk_density *
           sand_factor * instability_factor / 2000

tn_lbs = tss_tons * state_n_coefficient
tp_lbs = tss_tons * state_p_coefficient
```

## Protocol 2: Denitrification (Tidal Wetland)

Provides credit for nitrogen removal through denitrification processes in constructed tidal wetlands. Credit is based on planted tidal wetland area.

```
tn_lbs_reduced = 85.0 * planted_tidal_wetland_area_acres
```

## Protocol 3: Sedimentation (Marsh Accretion)

Awards credits for phosphorus and sediment trapping through sedimentation and marsh accretion processes. Based on marsh area receiving sediment deposition.

```
tp_lbs_reduced = 5.289 * marsh_area_acres
tss_tons_reduced = 3.4795 * marsh_area_acres
```

## Protocol 4: Marsh Redfield Ratio (Plant Uptake)

Credits nutrient uptake by marsh vegetation based on the Redfield ratio, which describes the stoichiometric relationship between carbon, nitrogen, and phosphorus in marine biomass.

```
tn_lbs_reduced = 6.83 * marsh_area_acres
tp_lbs_reduced = 0.30 * marsh_area_acres
```

#### State-Specific Coefficients

Protocol 1 uses state-specific coefficients to convert prevented sediment to nutrient reductions, reflecting regional differences in soil nutrient concentrations.

| State-specific conversion coefficients for prevented sediment protocol | TN Coefficient | TP Coefficient | TSS Factor |
| ---------------------------------------------------------------------- | -------------- | -------------- | ---------- |
| District of Columbia                                                   | 0.04756        | 0.03362        | 164        |
| Delaware                                                               | 0.04756        | 0.03362        | 164        |
| Maryland                                                               | 0.04756        | 0.03362        | 164        |
| Virginia                                                               | 0.01218        | 0.00861        | 42         |

Default Input Parameters

<table data-search="false"><thead><tr><th>Parameter</th><th>Default Value</th><th>Unit</th></tr></thead><tbody><tr><td>Length of living shoreline</td><td>1,000</td><td>feet</td></tr><tr><td>Existing average bank height</td><td>4.0</td><td>feet</td></tr><tr><td>Existing shoreline recession rate</td><td>1.0</td><td>feet/year</td></tr><tr><td>Soil bulk density</td><td>93.6</td><td>lbs/cu ft</td></tr><tr><td>Sand reduction factor</td><td>0.551</td><td>—</td></tr><tr><td>Bank instability reduction factor</td><td>1.0</td><td>—</td></tr><tr><td>Planted tidal wetland area</td><td>0.25</td><td>acres</td></tr></tbody></table>

Acronyms

| BMP | Best Management Practice |
| --- | ------------------------ |
| CBP | Chesapeake Bay Program   |
| TN  | Total Nitrogen           |
| TP  | Total Phosphorus         |
| TSS | Total Suspended Solids   |

#### Attribution

The Shoreline Restoration Load Reduction model estimates nutrient and sediment reductions using data and algorithms from the [2019 Shoreline Management Expert Panel Report](https://d18lev1ok5leia.cloudfront.net/chesapeakebay/documents/Final_Shoreline-Management_RPT__APPENDICES_12-18-19.pdf) developed by the Chesapeake Bay Program.

The Expert Panel developed four protocols for nitrogen, phosphorus, and sediment reductions: prevented sediment, denitrification, sedimentation, and marsh Redfield ratio. These protocols enable Bay states to use shoreline management practices as part of their overall watershed strategy.


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