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<th><center>Sedimentation/ Settling Only (Sediment Traps/ Basins)</center></th>
 
<th><center>Sedimentation/ Settling Only (Sediment Traps/ Basins)</center></th>
 
<th><center>Filtration Only (Silt Fence, Dewatering Bag, Geotextile, etc.)</center></th>
 
<th><center>Filtration Only (Silt Fence, Dewatering Bag, Geotextile, etc.)</center></th>
<th><center>Pretreatment + Chemical Flocculants + Settling/Filtration<sup>2</sup></center></th>
+
<th><center>Pretreatment<sup>1</sup> + Chemical Flocculants + Settling/Filtration</center></th>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
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<tr>
 
<tr>
 
<td>Sediment control</td>
 
<td>Sediment control</td>
<td><center>Primary benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Primary benefit</center></td>
+
<td><center>Better results</center></td>
<td><center>Primary benefit</center></td>
+
<td><center>Best results</center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td>Nutrient loading</td>
+
<td>Nutrient loading<sup>2</sup></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Better results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Best results</center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
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<tr>
 
<tr>
 
<td>Total suspended solids</td>
 
<td>Total suspended solids</td>
<td><center>Primary benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Primary benefit</center></td>
+
<td><center>Better results</center></td>
<td><center>Primary benefit</center></td>
+
<td><center>Best results</center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
<td>Total phosphorus</td>
+
<td>Total phosphorus<sup>2</sup></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Better results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Best results</center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
 
<td>Heavy metals</td>
 
<td>Heavy metals</td>
<td><center>Secondary benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Better results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Best results</center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
 
<td>Floatables</td>
 
<td>Floatables</td>
<td><center>Primary benefit<sup>1</sup></center></td>
+
<td><center>Little or no benefit<sup>3</sup></center></td>
<td><center>Little or no benefit</center></td>
+
<td><center>Good results</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Good results<sup>3</sup></center></td>
 
</tr>
 
</tr>
 
<tr>
 
<tr>
 
<td>Oil and grease</td>
 
<td>Oil and grease</td>
<td><center>Primary benefit<sup>1</sup></center></td>
+
<td><center>Little or no benefit<sup>3</sup></center></td>
<td><center>Little or no benefit</center></td>
+
<td><center>Some benefit</center></td>
<td><center>Secondary benefit</center></td>
+
<td><center>Some benefit<sup>3</sup></center></td>
 
</tr>
 
</tr>
 
</table>
 
</table>
<font size=1><sup>1</sup>If skimmer is used, otherwise secondary design benefit.<br>
+
<font size=1><sup>1</sup> Pretreatment via settling and/or filtration.<br>
<sup>2</sup>Benefits depend on the pH and temperature of the water being treated.</font size>
+
<sup>2</sup> For soil-borne nutrients; i.e., not dissolved forms.<br>
 +
<sup>3</sup> Benefit can be significantly improved with the use of a floating skimmer for discharge
 +
</font size>
  
 
[[category:table]]
 
[[category:table]]

Revision as of 19:54, 13 June 2019

Expected performance benefits for various dewatering practices.
Link to this table

Dewatering Best Management Practices
Sedimentation/ Settling Only (Sediment Traps/ Basins)
Filtration Only (Silt Fence, Dewatering Bag, Geotextile, etc.)
Pretreatment1 + Chemical Flocculants + Settling/Filtration
Water quantity
Flow attenuation
Secondary benefit
Little or no benefit
Little or no benefit
Runoff volume reduction
Secondary benefit
Little or no benefit
Little or no benefit
Water quality
Soil erosion
Little or no benefit
Little or no benefit
Little or no benefit
Sediment control
Good results
Better results
Best results
Nutrient loading2
Good results
Better results
Best results
Pollutant removal
Total suspended solids
Good results
Better results
Best results
Total phosphorus2
Good results
Better results
Best results
Heavy metals
Good results
Better results
Best results
Floatables
Little or no benefit3
Good results
Good results3
Oil and grease
Little or no benefit3
Some benefit
Some benefit3

1 Pretreatment via settling and/or filtration.
2 For soil-borne nutrients; i.e., not dissolved forms.
3 Benefit can be significantly improved with the use of a floating skimmer for discharge