Memo. Annual Detention Pond Inspection Report. Detention Pond No. 1

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Gavin Gibbs
5 years ago
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Memo Date: August 29 th, 2011 To: Ms. Toni K irkland F rom: Brian K ing, P.E. Re: Broodshade Detention Pond Inspections Phone: 770-442-0500 www.engineering303.

5 miles North of Mayfield Road. Brookshade was originally permitted in unincorporated Fulton County.

1 Memo Date: August 29 th, 2011 To: Ms. Toni K irkland F rom: Brian K ing, P.E. Re: Broodshade Detention Pond Inspections Phone: Annual Detention Pond Inspection Report Brookshade subdivision is located in North Fulton County within the newly formed City of Milton on the west side of Hopewell Road, 1.5 miles North of Mayfield Road. Brookshade was originally permitted in unincorporated Fulton County. The subdivision was constructed in four phases by The Chatham Holdings Corporation between 1997 and The Subdivision has 3 detention ponds as shown on the final plats prepared by David A. Burre Engineers and Surveyors Inc. The final plat for Unit One is dated and revised on The final plat for Unit Two is dated and revised on The final plat for Unit Three is dated and revised on The final plat for Unit Four is dated On August 23 th I performed a visual inspection of the three detention facilities at the request of Toni Kirkland with Brookshade HOA. Detention Pond No. 1 This pond is located in Unit Two of the subdivision on the rear of lots 21 & 22, a.k.a. street address 902 and 912 North Brookshade Parkway. The pond was designed as an open dry pond and was approved by Fulton County between 1995 and The pond is now over 15 years old and through natural regeneration has become a wooded pond with volunteer Pines and Hardwood trees.

It is my opinion that this pond is functioning fine and is within the design tolerances of the approved detention pond.

2 2 An inspection of this facility found the detention pond and security fence around the pond in good shape. I inspected both inlet headwalls, the outlet control structure, the outlet headwall and the detention pond berm. It is my opinion that this pond is functioning fine and is within the design tolerances of the approved detention pond. This is based on a visual inspection and as such I cannot verify that the existing pond meets the design volumes, but there is no evidence of excessive silt within the pond. It is my opinion that the detention facility is in good condition and does not require any additional maintenance this year. I would recommend continuing the monthly inspections by the HOA to clean and remove debris from the inlet and outlet structures and inspect the perimeter security fence around the pond. This pond is located in Unit Three of the subdivision on the rear of lots 91 & 92, a.k.a. street address 300 and 290 Oakhurst Leaf Drive. This pond was designed as an open dry pond and was approved by Fulton County in The pond is now over 14 years old and through natural regeneration has become a wooded pond with volunteer Pines and a few Hardwood trees. An inspection of this facility found the detention pond and security fence around the pond in good shape, except for two minor problems. One section of the security fence on lot 91 (300 Oakhurst Leaf Drive) is undermined and Undermine fence post

3 the original Rip-Rap filter berm on the south end of the pond, downstream of the inlet head wall on lot 92, has caused the inflows to be redirected against the side slope of the detention pond.

Neither of these minor problems affect the functionality of the pond and it is my opinion that this pond is functioning fine and is within the design tolerances of the designed pond.

Recommended Repairs Eroded side slope I recommend placing rip-rap in the area where the fence post is undermined to prevent any further erosion migrating into the back yard of lot 91.

3 3 the original Rip-Rap filter berm on the south end of the pond, downstream of the inlet head wall on lot 92, has caused the inflows to be redirected against the side slope of the detention pond. This has caused a small area of the side slope to erode. Neither of these minor problems affect the functionality of the pond and it is my opinion that this pond is functioning fine and is within the design tolerances of the designed pond. This is based on a visual inspection and as such I cannot verify that the pond meets the design volumes, but there is no evidence of excessive silt within the pond. Recommended Repairs Eroded side slope I recommend placing rip-rap in the area where the fence post is undermined to prevent any further erosion migrating into the back yard of lot 91. This Rip- Rap can be taken from the filter ring, as the filter ring needs to be lowered to provide a clear path for the stormwater run-off through the pond. I would also recommend thinning the pine trees in this pond in the near future to minimize the Heavy understory chance of the pond clogging during periods of heavy rains. This thinning will also improve the health of the remaining trees within the pond.

This pond is located in Unit Four of the subdivision on the rear of lots 102, 103,104 117 &118, a.k.a. street address 545, 555 & 565 Oakleaf Way and 150 & 140 Oakhurst Leaf Drive.

4 4 It is my opinion the detention facility is in good condition. I would recommend continuing the monthly inspections by the HOA to clean and remove debris from the inlet and outlet structures and inspect the perimeter security fence around the pond. This pond is located in Unit Four of the subdivision on the rear of lots 102, 103, &118, a.k.a. street address 545, 555 & 565 Oakleaf Way and 150 & 140 Oakhurst Leaf Drive. The pond was designed as an online pond (that is a detention pond constructed on an existing stream) and was approved by Fulton County in The pond is now over 14 years old. An inspection of this facility found the detention pond and security fence around the pond in good shape, except for two minor problems. One section of the wooden fence on lot 102 (545 Oakleaf Way) is broken and the chain link backing to the security fence is open on the same lot. Neither of these minor problems affect the functionality of the pond and it is my opinion that this pond is functioning fine and is within the design tolerances of the designed pond. This is based on a visual Open fence inspection and as such I cannot verify that the pond meets the design volumes, but there is no evidence of excessive silt within the pond. Recommended Repairs I recommend repairing both sections of the fence as soon as possible. Otherwise, it is my opinion that the detention facility is in great condition. I would recommend continuing the monthly inspections by the HOA to clean and remove debris from the inlet and outlet structures and inspect the perimeter security fence around the pond. Broken fence

5 5 Addition photographs of the outlet structure and the stream flowing through the detention pond.

KENT COUNTY STORMWATER MAINTENANCE DISTRICT STORMWATER BMPs MAINTENANCE TASKS AND RESPONSIBILITIES GUIDANCE DOCUMENT BIO-RETENTION FACILITIES

KENT COUNTY STORMWATER MAINTENANCE DISTRICT STORMWATER BMPs MAINTENANCE TASKS AND RESPONSIBILITIES GUIDANCE DOCUMENT BIO-RETENTION FACILITIES BIO-RETENTION FACILITIES (for all basins / BMPs) Annually Prepare Operation and Maintenance Plan. Clearly outline how vegetation in the facility and its buffer area will be managed or harvested in the