Post - Construction Inspection Of BMPs

Question 1

During a post construction inspection of a Sheet Flow to Filter Strip or Open Space, what 6 things should an inspector look for?

Answer 1

1). Flows through the filter strip do not short-circuit the overflow control section; 2). Debris/sediment does not build up at the top of the filter strip; 3). Foot/vehicle traffic does not compromise the gravel diaphragm; 4). Scour/erosion do not occur within the filter strip; 5). Sediments cleaned out of level spreader forebay; 6). Vegetative density exceeds 90% in boundary zone or grass filter.

Question 2

When is the ideal time to hold a post construction inspection for a Sheet Flow to Filter or Open Space BMP?

Why?

Answer 2

Ideally, inspections should be conducted in the non-growing season when it is easier to see the flow path.

VA DEQ Spec. 2 Page 18/20

Question 3

What types of maintenance operations might be triggered by annual post construction inspections of Grass Channel BMPs?

Answer 3

• Sediment Removal
• Spot Re-vegetation
• Inlet Stabilization

VA DEQ Spec. 3 Page 19/21

Question 4

When is the ideal time for a post construction inspection of a Grass Channel BMP?

How often?

Answer 4

In the spring of each year

VA DEQ Spec. 3 Page 19/21

Question 5

What should a plan for initial inspections of a Soil Compost Amendment BMP look like in order to ensure their success?

Answer 5

For the first six months following the incorporation of soil amendments, the site should be inspected at least once after each storm event that exceeds 1/2 inch of rainfall.

VA DEQ Spec. 4 Page 7/10

Question 6

What three main topics should an inspector consider while completing a post construction inspection of Soil Compost Amendments?

Expand on each main topic.

Answer 6

• Spot Reseeding (are there bare or eroding areas in the contributing drainage area)
• Fertilization (look at plant vigor, depending on the amended soils test, a one-time spot fertilization may be needed in the fall)
• Watering (water once every three days for the first month and then weekly for the first year in April to Oct. depending on rainfall.

Question 7

When should post construction inspections take place for Vegetative Roof BMPs and what main things should an inspector be looking for?

Answer 7

A vegetative roof should be inspected twice a year during the growing season to asses vegetative cover, and to look for leaks, drainage problems and any rooftop structural concerns.

VA DEQ Spec. 5 Page 15/17

Question 8

What details related to vegetation inspection should be conducted on Vegetative Roof BMPs during post-construction inspections?

Answer 8

Inspectors should look for dead, dying, or invasive vegetation to be hand-weeded/removed. Plants/media should be added to any bare areas. Inspect roof drains, scuppers, and gutters to ensure they are not overgrown or have organic matter deposits. Remove any accumulated organic matter/debris.

VA DEQ Spec. 5 Page 15/17

Question 9

What might be important to ensure adequate authorization for inspection of Vegetative Roof BMPs?

Answer 9

Written documentation between the local inspection authority and the property owner or manager.

VA DEQ Spec. 5 Page 14/17

Question 10

What action should be taken if a leak or crack is suspected in the waterproof membrane if a Vegetative Roof BMP?

Answer 10

A electric leak survey should be performed to pinpoint the exact location l, make localized repairs, and then establish system components and ground cover.

VA DEQ Spec. 5 Page 15/17

Question 11

What is an ideal maintenance schedule for post-construction inspections of Rainwater Harvesting BMPs?

Answer 11

All rainwater harvesting system components should be inspected by the property owner in the Spring and the Fall each year. A comprehensive inspection by a qualified third party inspector should occur every third year.

VA DEQ Spec. 6 Page 31/40

Question 12

What type (supplemental irrigation or indoor uses) of rainwater harvesting system has more complicated maintenance issues?

Answer 12

Systems that provide supplemental irrigation water have relatively low maintenance requirements, while systems designed for indoor uses have much higher maintenance requirements.

VA DEQ Spec. 6 Page 31/40

Question 13

What 4 types of maintenance activities should be inspected for Rainwater Harvesting BMPs at least once every year post construction?

Answer 13

1.) are gutters and downspouts free of leaves/debris; 2).inspect pre-screening devices and first flush diverted; 3). Inspect storage tank lids, check for mosquito screens, look for holes or gaps; 4). Inspect condition of overflow pipes, overflow filter path, and secondary runoff practices.

VA DEQ Spec. 6 Page 31/40

Question 14

What 5 types of maintenance activities should be inspected for Rainwater Harvesting BMPs at least once every three years post construction?

Answer 14

1). Inspect tank for sediment buildup; 2.) clear overhanging vegetation above roof; 3). Inspect integrity of backflip preventer; 4). Inspect structural integrity of tank, pump, pipe, and electrical system, and 5). Replace any damaged system components.

VA DEQ Spec. 6 Page 31/40

Question 15

How often should maintenance inspections for Permeable Pavement BMPs occur? At what time of year should it occur?

Answer 15

Maintenance of permeable pavement is driven by annual inspections. It is highly recommended that a spring maintenance inspection and cleanup be conducted.

VA DEQ Spec. 7 Page 22/25

Question 16

What should be inspected during a post-construction inspection of Permeable Pavement BMP? (Do not include anything that needs to be measured)

Answer 16

1). Inspect surface for sediment deposition, organic debris, staining or ponding that may indicate surface clogging; 2). Inspect structural integrity (slumping, cracking, spalling, broken pavers); 3). Check inlets, pretreatment cells, and flow diversion structures for sediment buildup and structural damage; 4). Inspect contributing drainage areas for erosion; 5). Is observation still capped?

Question 17

What should be “measured” during a post-construction inspection of Permeable Pavement BMP?

What conclusions can be drawn?

Answer 17

The drawdown rate should be measured at the observation well for three days following a storm event in excess of 1/2 inch in depth.

If standing water is observed in the well after three days, this is a clear sign that clogging is a problem.

VA DEQ Spec. 7 Page 22/25

Question 18

What 4 vegetation related issues should be inspected for Infiltration BMPs during post construction inspections?

Answer 18

1). Check that no vegetation forms an overhead canopy that may drop leaf litter/fruits that can clog the BMP; 2). Evaluate vegetative quality of adjacent grass buffer; 3). Inspect upland CDS for erosion; 4). Look for weedy growth on the stone surface of BMP.

VA DEQ Spec. 8 Page 19/24

Question 19

Why is weedy growth on the stone surface of an Infiltration BMP a “red flag” during a post construction inspection?

Answer 19

It might indicate sediment deposition or clogging.

VA DEQ Spec. 8 Page 19/24

Question 20

What should be “measured” during a post-construction inspection of an Infiltration BMP?

What conclusions can be drawn?

Answer 20

The drawdown rate should be measured at the observation well for three days following a storm event in excess of 1/2 inch in depth.

If standing water is observed in the well after three days, this is a clear sign that clogging is a problem.

VA DEQ Spec. 8 Page 18/24

Question 21

During a post construction inspection of a Bio-retention BMP, what should you look for with respect to the bio-retention bed?

Answer 21

Check the bio-retention bed for evidence of mulch floatation, excessive ponding, dead plants, or concentrated flows.

VA DEQ Spec. 9 Page 37/54

Question 22

During a post construction inspection of a Bio-retention BMP, where should you look for sediment buildup?

Answer 22

• Curb cuts, gravel diaphragms, or pavement edges that could cause bypassing.
• The pre-treatment cell or filter bed.
• Inflow points

VA DEQ Spec. 9 Page 37/54

Question 23

During a post construction inspection of a Bio-retention BMP, what vegetative related issues should you be looking for?

Answer 23

1). Is there 75% - 90% cover achieved in the bed (mulch and vegetation); 2). Did all vegetation survive winter/road salt application; 3). Look for bare soil or sediment sources in the contributing drainage areas; 4). Are there any invasive plants.

VA DEQ Spec. 9 Page 37-38/54

Question 24

During a post construction inspection of a Bio-retention BMP, what should you look for on side slopes or grass filter strips?

Answer 24

Evidence of any rill or gully erosion.

VA DEQ Spec. 9 Page 37/54

Question 25

During a post-construction inspection of a Dry Swale BMP, what are important things to inspect regarding check dams?

Answer 25

Inspect upstream and downstream of check dams for evidence of undercutting or erosion, and remove trash or blockages at weep holes.

VA DEQ Spec. 10 Page 20/21

Question 26

During a post-construction inspection of a Dry Swale BMP, what are important things to inspect regarding the filter bed?

Answer 26

Examine filter beds for evidence of braiding, erosion, excessive ponding, or dead grass.

VA DEQ Spec. 10 Page 20/21

Question 27

What is one difference between the post construction maintenance of a Dry Swale BMP and a Wet Swale BMP?

Answer 27

During an inspection of a Wet Swale, inspectors should look for “woody wetland vegetation” that may need to be removed periodically.

A DEQ Spec. 11 Page 8/9