Testing

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Section 8.2 - 8.9 content text (only) Appendix C as A SCROLLING DOCUMENT!!!

Mention training courses

Soil Characterization Testing[edit]

The soil component of an LID BMP contributes substantially to its stormwater treatment performance and overall function. If the soil is overly compacted or very finely textured, it may drain too slowly. If the soil is highly organic or contains excessive amounts of chemical fertilizer it may contribute to nutrient loads to receiving waters rather than reduce them. If the soil is too shallow it may not provide adequate treatment of contaminated stormwater or may not support healthy vegetation. Whether it be the engineered filter media of bioretention cells, the growing media of green roofs or the topsoil of enhanced swales, vegetated filter strips and soil amendment areas, it is important that the soil provide a healthy growing environment for plantings while being within design specifications for key parameters specific to the type of BMP.

It is most important to sample and test soil characteristics as a part of Construction and Assumption inspections, to confirm the BMP has been constructed with materials that meet design specifications and that installation of the soil component is acceptable. Testing to confirm that the material meets quality specifications (i.e., particle-size distribution, organic matter, pH, cationic exchange capacity, nutrients and soluble salts) needs to be completed prior to it being delivered to the construction site. Testing to confirm that installation of the soil component is acceptable (i.e., depth and compaction) should be performed after the installed material has been allowed to settle for at least two (2) weeks, and prior to planting.

Sampling and testing is also recommended as a part of Verification inspections, to determine if the BMP is being adequately maintained and if soil characteristics are still within acceptable ranges. It may also be done as part of Forensic inspection and Testing (FIT) work to help diagnose the cause of poor vegetation cover, drainage or treatment performance and decide on corrective actions.


Critical soil characteristics, acceptance criteria and tests by LID BMP type

LID BMP Type

Soil Characteristic

Acceptance Criteria*

Test
Bioretention/Bioswales/Dry swales
Texture** Loamy Sand or Sandy Loam; 70 to 88% sand-sized particles; 12 to 30% silt- and clay-sized particles; <20% clay-sized particles. Particle-Size Distribution (PSD), or % Sand/Silt/Clay (i.e., Soil Texture) plus Sand Fraction
Organic Matter (OM) 3 to 10% by dry weight** Walkley-Black method when OM <7.5% or Loss On Ignition (LOI) method when OM ≥7.5%*** Inlet
Inlet/Flow Spreader Structural Integrity x x x
Inlet/Flow Spreader Structural Integrity x x x x
Pretreatment sediment accumulation x x x
Inlet erosion x x
Perimeter
BMP dimensions x x x
Side slope erosion x x
Surface ponding area x x x
Filter Bed
Standing water x x x
Trash x x
Filter bed erosion x x
Mulch depth x x x x
Filter bed sediment accumulation x x x
Surface ponding depth x x x
Filter bed surface sinking x x x
Check dams x x x x
Planting Area
Vegetation cover x x x x
Vegetation condition x x
Vegetation composition x x x
Outlet
Monitoring well condition x x x x
Sub-drain/Perforated pipe obstruction x x
Overflow outlet obstruction x x x x



The image above shows a manual soil corer, a split soil core sampler kit which preserves the soil sample for further testing (i.e., bulk density) and acrylic core sample tubes. All examples of tools to be use for soil characterization testing. Source: (TRCA, 2016).[1].
Testing Indicators Framework - Bioretention/Swales

Component

Indicators

Construction Inspection

Assumption Inspection

Routine Operation Inspection

Verification Inspection
Testing Indicators
Soil characterization testing x x (x)
Sediment accumulation testing x x x x
Surface infiltration rate testing x (x)
Natural or simulated storm event testing x (x)
Continuous monitoring x (x)
Note: (x) denotes indicators to be used for Performance Verification inspections only (i.e., not for Maintenance Verification inspections)

Sediment Accumulation Testing[edit]

Surface Infiltration Rate Testing[edit]

Natural or Simulated Storm Event Testing[edit]

Continuous Monitoring[edit]

Green Roof Irrigation System Testing[edit]

Green Roof Leak Detection Testing[edit]

Cistern Pump Testing[edit]

References[edit]

  1. STEP. 2016. Low Impact Development Stormwater Management Practice Inspection and Maintenance Guide. https://sustainabletechnologies.ca/app/uploads/2016/08/LID-IM-Guide-2016-1.pdf