Transcript LAND DEVELOPMENT DIVISION ENGINEER FORUM

LAND DEVELOPMENT DIVISION
ENGINEER FORUM
February 23, 2012
Conference Room D
Today’s Agenda
• 2009 SCDHEC’s Audit Findings
• 2010 Woolpert’s Internal Audit Findings
• Results from Summer 2011 Survey
• Proposed Changes
• EPA and SCDHEC Regulation Forecast
• Status and expected contents of our next
NPDES MS4 permit
Land Development Regulations
• Land Development Regulations Update
• Stakeholder Approach
• Time Frame – Begin March 2012 & up to 1
year to complete stakeholder review
• Includes LID’s, TND’s, Centers & Corridors,
Traffic Impact, etc.
• Update Zoning Ordinance to reflect
changes in LDR
SCDHEC’s Audit Results
• EPA guidance requires SCDHEC to conduct an in•
•
depth audit at least once every five (5) years
In March of 2009 SCDHEC held a two day audit
covering all 13 elements of our MS4 Permit
The conclusion was Greenville County’s program
was satisfactory with deficiencies in two
elements:
– Construction Site Runoff
– Public Education and Public Participation
DHEC’s Audit Comments
• …” The County needs to improve documentation
•
of how they are determining that BMP’s
proposed on sites that drain to Impaired Waters
(both 303(d) listed and those included in a
TMDL) are adequate to address the pollutant of
concern in the receiving water body.”
“Overall, Greenville County is not effectively
approving construction site plans to MEP
standards. The MS4’s focus must be on water
quality.”
SCDHEC Audit Comments
• Silver Meadows Phase III: SCR10I232
• 1. Greenville County application form says 25 disturbed acres; NOI says 23.9
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•
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disturbed acres
2. One engineer signed and sealed Greenville County application and different
engineer signed and sealed plans and NOI
3. NOI indicates impacts to 121' stream-not mentioned or shown on plans; the area
of impacts should be clearly identified and shown on the plans
4. No wetlands/ waters of the State delineation on plans-impacts to wetlands/ waters
of the State cannot be assessed/ reviewed if the delineation is not shown on the
plans. Surveyed delineation must be shown on the plans; plans must be reviewed to
ensure that appropriate BMPs are provided to prevent sediment from washing into
wetlands/ waters of the State and to ensure that basins/ traps/ any structures shown
in the SWPPP are not being constructed in wetlands/ waters of the State without
appropriate Corps' 404 permit and SCDHEC 401 certification. See Section 2.1C of
SCR100000. If the entire SWPPP cannot be implemented and a 404 permit is needed
for the associated impacts to wetlands/ waters of the State, then NPDES coverage
cannot be issued until 404 permit has been issued and is effective (SC DHEC 401
certification of the 404 permit must be issued for 404 permit to be issued and
effective).
5. Pre- and post-development drainage area maps and during construction drainage area map
that clearly correspond to the calculations not provided-these maps must be provided to
ensure that at least the entire analyzed in pre-development " calculations is analyzed in
the post-development calculations and to check that the area modeled as draining to a
structure actually drains to that structure. According to the provided calculations, 1.21
acres less area was analyzed in the postdevelopment calculations-that is not acceptable.
Post-development flows must be less than pre-development flows at all discharge points.
The same or a greater area must be analyzed for the post-development calculations for an
accurate comparison.
6. Several inconsistencies between plans, details, and calculations for pond 1: Top of pond
elevation, top of riser elevation, emergency spillway width, orifice sizes and elevations.
The inconsistencies in the top of riser elevation are a major problem because the top of
the riser on the detail is 903'. In the calculations, the top is at 907.5'. The 10-year water
surface elevation in the calculations is 904.6', so flows would be going through the top of
the riser, if constructed using the elevation listed on the detail, which could mean the peak
10-year flows are greater than the pre-development flows and regulatory requirements
may not be met. Many of the elevations and dimensions used in the IDEAL model
calculations are different from those on the plans and details and in Sedcad calculations.
Also, in the IDEAL model, the drainage area for the pond was listed as 34 acres; however,
in the Sedcad calculations, the drainage area for the pond was 53 acres.
7. On the pond 1 detail and chart, the same orifice elevations are listed as being the invert
and centerline elevations. For example, on the detail, 2-10" orifices are listed at 905',
invert elevation. However, on the chart, 2-10" orifices are listed at 905', centerline
elevation. The calculations would not be able to be reviewed without knowing whether the
elevations are invert or centerline. The Sedcad calculations would then need to be
reviewed to ensure that the orifices were entered using their centerline elevation,
according to the Sedcad memo on our website.
8. Sedcad calculations were not reviewed in accordance with Sedcad memo posted on our
website. Orifices with diameters greater than 3" were modeled in Sedcad.
9. For pond 1, the water quality volume was listed as 2.478 ac-ft on the detail. However, the
water quality volume is 4.42 ac-ft. Also, Sedcad cannot be used for the water quality
calculations because flows are still coming into the pond. The water quality calculations are for a
brimful drawdown-the entire water quality volume must be in the pond at one time and then
released over at least 24 hours, with no flows coming into the pond during the release. Also,
need water quality drainage area map that shows the areas that should drain to each pond. In
the water quality calculations for pond 2, the elevations and orifice size used in the calculations
does not correspond to the plans (bottom at 882' on plans, 956' in calculations; top at 886' on
plans, 972' in calculations; 2" orifice on plans, 2.5" orifice in calculations). Also, the calculations
do not show that the volume is released over at least 24 hours. In 24 hours, more than the
water quality volume has drained out, which means the water quality volume drained out in less
than 24 hours. For pond 3, it does not appear that the water quality volume is contained within
the water quality basin. Also, the elevations on the plans do not correspond to the elevations in
the calculations.
10. Water quality ponds should have been included in post-development calculations , because
some detention is provided and timing effects should have been reviewed because of existing
flooding problems.
11. No limits of disturbance on plans (23.9 disturbed acres, 75 total acres)
12. No proposed contours shown for lots and no note regarding assumed disturbed area per lotproposed contours should be shown for all areas within limits of disturbance, except individual
lot disturbance with no mass grading
13. Ponds and swales to divert flows to the ponds should be in easements or common areasthis does not appear to be true for the flows from lots 38-51
14. Are ponds to be used as sediment basins during construction? That is not clear from the
plans, but the construction sequence mentions that sediment ponds and traps and
diversions to them are to be installed. Sediment calculations were provided for a big basin
and smaller drainage areas through silt fence. The calculations for the smaller areas that
were modeled through silt fence do not appear to be accurate after the storm drain
system is installed. The flows through the storm drain system will not sheet flow to the silt
fence as modeled.
15. Construction sequence not in correct order-basins and traps and diversions to them must
be installed before clearing, grubbing, and grading activities, except the clearing and
grubbing in the area of the basins, traps, and diversions. Also, General Note 3 on sheet
SW-4 states that diversions and traps are to be provided beginning with grading. Traps
and diversion should be provided before clearing and grubbing-note should be amended.
Also, Implementation note 1 states that erosion control measures begin with grading-note
should be amended to require sediment and erosion control measures before clearing and
grubbing.
16. Water quality ponds not shown on Erosion Control plan, SW-2. Construction sequence
does not specify when they are to be installed, if they are not to be used during
construction.
17. Check dams needed in all temporary diversions; temporary diversions to the sediment
basin and traps, if any will be used as mentioned in construction sequence, must be
shown on the plans.
18. During construction outlet from line I appears to drain to silt fence. Silt fence should not
be used in areas of concentrated flows. A more substantial structure is needed at this
outlet during construction.
19. Sediment trap detail: No cleanout information listed, sizing criteria (3600 ft3/ acre) not
provided on detail, no maximum drainage area listed on detail (maximum of 5 total acres).
No trap labeled or shown on plans, but sediment trap sizing calculations provided for 12.1
acres. Trap cannot be used for 12.1 acres.
20. Inlet protection: Sediment tube inlet protection detail was the only inlet protection detail
provided, and it is only for pre-paving. The plans call for fabric drop inlet protection, but no
detail provided on plans.
21. Lot detail: double row of silt fence to protect wetlands/ waters of the State where 50'
undisturbed buffer cannot be maintained
22. Riprap sediment dike-no detail provided but called for on plans
23. Sediment check detail-no detail provided but called for on plans
24. Sheet SW-4, General note 8 should be omitted-the sediment and erosion control measures
shown on the plans are not just recommendations; the measures must be implemented as
shown on the plans. Or, the note could be amended to explain allowable minor modifications
and the process for major modifications (involving calculations, etc.).
25. Note on sheet SW-1 about riprap pad at outlet into pond 1 refers to sheet 8 for table.
Sheet 8 was not provided.
26. Energy dissipator: note at outlet in pond 3 on sheet SW-1 refers to sheet 7 for energy
dissipator. Sheet 7 not provided.
27. Old stabilization note, bottom left-hand corner of sheet SW-4, note 3
Springs at Greenville Apartments: SCR10K471
1. Pond maintenance plan and Flogard Plus maintenance plan not provided
2. On page 4 of the report, the consultant indicated that the site development will not
contribute to the BIO impairment or fecal impairment (TMDL). That is not acceptable. BIO is
an impairment that is expected to be affected by construction stormwater discharges, unless
the consultant can justify how sediment will not be contained in the construction stormwater
discharges.
3. The pre- and post-development analysis cannot be fully reviewed because the analysis
points are different according to the pre- and post-development drainage area maps. The
same analysis points should be used for pre- and postdevelopment calculations; also, the
analysis points should be the points where flows leave the site/ property. For example, the
analysis point for predevelopment area 2 should have been an analysis point in the postdevelopment condition because flows continue to leave the property at this point in the postdevelopment condition. However, the analysis point for this side of the property was moved
and now includes the undetained portions of the site, some of which flow directly to the creek
and not onto the adjacent property. Also, the entire area included in pre-development area 2
does not drain to the analysis point shown on the drainage area map; part of the area sheet
flows to the adjacent property. Therefore, the analysis is not accurate.
4. According to the plans, sediment trap 1 is shown at the end of the outlet pipe from basin 1
and trap 2 is shown in basin 1 at the end of a pipe/ temporary diversion ditch-maximum
drainage area for a trap is 5 acres, which it appears was exceeded for traps 1 and 2. Sediment
trap sizing calculations and trapping efficiency calculations were not included in the report.
Drainage area map that shows the maximum drainage area for each sediment trap and basin,
throughout the life of the construction project not provided. Sediment trap symbols associated
with check dams shown along the temporary diversion ditch that empties into basin 1/ trap 2.
Each of those sediment traps must be designed to account for the entire area that drains into
it, not just the direct area. Sediment trap sizing calculations should have been provided for all
sediment traps.
5. Sedcad calculations for pond 1: only 12.24 acres were routed through the pond; according
to the post-development drainage area maps, 14.43 acres drains to pond l. Revised
calculations are needed. Also, the 25-year storm overtops the emergency spillway; the 10year storm event must be contained below the spillway. This could not be reviewed because
10-year storm event calculations were not provided.
6. Hydraflow calculations for basin 1: emergency spillway/weir B goes from 913' to the top of
the pond; however, according to the plans, the weir is a 6" slot to an 18" pipe. It does not
appear that the structure is accurately modeled because the actual capacity appears to be
limited to less than what is modeled in Hydraflow.
7. If pond 1 will be a wet pond, then the curve number should be 98. However, according to
the post-development curve number map, the curve number used for it was 61. Need
amended curve number and post-development calculations.
8. First flush calculations for pond 2: surface area used in the calculations does not correspond
to the surface area in Hydraflow or on the chart-orifice appears to be too large and will
release the first flush volume in less than 24 hours. Revised first flush and post-development
routing calculations needed.
9. IDEAL model calculations: dimensions and elevations used in the calculations do not
correspond to plans and details (outlet pipe diameter for pond 1, separate weir for pond 2,
etc.) 10. Because of the complexity of the plans, phased grading plans needed. The initial
phase would show the grading necessary to install the basins and traps and diversions to
those structures, along with the perimeter sediment and erosion control measures.
11. Limits of disturbance shown through the western wetlands area
12. No sediment and erosion control measures shown on sheet C-202-appears that the silt
fence, inlet protection, check dams, sediment traps, etc. layers are not shown because those
features are shown on sheet C-201 in the area on either side of the matchline on sheets C201 and 202.
13. Need permission from the adjacent property owner, McGinnis, to build retaining wall on the
property line, or show how the wall will be able to be constructed on the property line
without access to the lower side of the wall.
14. Hatched area to the east of basin 2 and the proposed sewer line, parallel to the road-label
for this area cut off
15. No sediment and erosion control measures provided for the area of installation of the outlet
pipe for basin 2, which is shown as being installed up to the edge of the creek
16. Outlet protection not provided for the pipe under the emergency entrance
17. Installation of temporary diversions to the sediment basins and installation of the sediment
traps not included in the construction sequence-diversions must be installed as soon as the
basins are completed before the site is cleared or grubbed. Check dams should be installed
in all temporary diversions.
18. On the plans, the label for the riprap protection for the stream crossing area refers to the
detail-did not see where a detail of this area was included. A stream crossing detail
showing sediment and erosion control measures that will be used to prevent sediment from
entering the wetlands/ waters of the State should be provided.
19. Energy dissipator detail: structures 25, 50, 44, 54, 48, and 56 are listed. Energy dissipators
are needed for structures 55, 57, 51, and 43 and are not listed.
20. A detail for Flogard Plus was provided. The inlets that will have Flogard Plus protection
installed must be listed on the plans or details.
21. Riprap forebay-no detail provided but called for on plans
22. Permanent diversion swale-no detail provided but called for on plans
23. Check dam detail-cleanout information not listed
24. Sediment trap detail: sizing information only provided for traps 1 and 2; however, several
other traps are shown on the plans
25. Riprap dike-no detail provided but called for on plans
26. Diversion ditch and diversion berm details-only detail provided for diversion swale; make
sure labeled consistently on plans and details
1.
2.
3.
4.
5.
6.
Upstate Commercial Park: SCRl0I664
As-built survey of existing ponds should have been provided before NPDES coverage issueddid not see in either permitting file; if ponds not built according to previously approved
calculations, then must be modified to correspond to previously approved calculations or
new post-development, water quality, dewatering calculations must be submitted to show
that the pond, as built, meets regulatory requirements; if problems with original
calculations, should be corrected in new as-built calculations (outlet pipes from ponds 18",
but pipes under road 15")
BIO impairment not addressed-see item 22 of checklist and section 3.4C.2.c; SWPPP must
contain qualitative and quantitative assessment of proposed BMPs
Difficult to review because not clear on plans what is existing and what landdisturbing
activities are being covered under this NPDES coverage; disturbed area on NOI is 29 acres
(same as disturbed area for previous NPDES coverage but appears that part of site has been
developed and would not be re-disturbed). Narrative says this coverage is for lot
construction; however, plans say each lot construction needs its own permit
Inlet protection not shown on plans
Swales and diversions to existing basins must be in easements or common areas (from lots
1-4 to catch basin near lot 5, dike on lots 9 and 10, dike and swales on lots 12-16 and 11)previous plans show some drainage easements for off-site flows to lots 4-6 but not shown
on current plans
Construction sequence not specific far this phase-mentions clearing and grubbing for basins
and installation of basins; according to plans, basins are existing
Lake Conestee Nature Park Phase 2 Paved Trail: SCR10K137
1. BIO impairment not addressed-see item 22 of checklist and section 3.4C.2.c; SWPPP must
contain evaluation of proposed BMPs
2. Because portions of the trail are not connected (because boardwalk areas are not included in
this portion of the project), the limits of disturbance should also include areas for access to the
disconnected portions of the trail-construction entrances should be provided in all locations
where access is provided from a paved roadway
3. Maintenance requirements for vegetated swale not included-SWPPP mentions native plants
but no specific maintenance plan provided
4. No surveyed delineation shown on plans. Areas where land-disturbing activities cannot occur
until Corps' pen-nit issued must be shown and labeled on plans. Dr. Beacham's letter only
mentions the absence of wetlands in the project area-the presence of waters of the State must
also be determined; NPDES coverage cannot be issued until Corps' permit issued if
implementation of the SWPPP is affected by the Corps' permit-implementation of the SWPPP
cannot be determined unless surveyed delineation is shown on plans
5. No limits of disturbance shown on the plans
6. Double row of silt fence not provided where 50' undisturbed buffer cannot be maintained
between wetlands/waters of the State and the disturbed area
7. Construction entrance-not shown on plans; must be provided; also detail must be provided
8. Outlet protection sizing information not provided-plans call for erosion control matting;
calculations showing that specified ECM is adequate must be provided; culvert locations must
be shown on the plans
Creekwood S/D Ph II, PN SCR10J644, File No. 23-08-08-O5
l. The hydrologic analysis was not done pre- and post-development at each outfall. Pre- and
post- was only done for the main basin.
2. The hydrology indicated Ponds A and G would discharge the 10-yr storm in less than 24
hours.
3. The Table of Contents given in the SWPPP bears no resemblance to the actual document.
This makes it nearly impossible to follow the hydrologic analysis of this site.
4. From the hydrology, it appears the site is being delineated into smaller drainage basins to
preclude the requirement for detention thru controlled outflow structures.
5. There are no as-builts for the existing on-site pond. The narrative indicates this pond is to be
used as a stormwater management structure.
6. There is no signed maintenance agreement for the pond or the level spreaders.
7. The narrative states this site is to be mass-graded, then states no detention is needed due
to No Significant Impact from the development of the site.
8. Permanent Water Quality is not addressed. The plan proposes using the onsite pond for
"water management", but no rationale for this proposal is supplied, nor are alternative means of
treatment addressed or explored.
9. Drainage area maps are inadequate/unclear.
10. Slope stabilization is not specified or detailed.
11. Limits of disturbance and proposed contour elevations are not indicated.
12. The plan is missing Standard Notes #1, 5, 9, and 10.
Fork Shoals Road Self Storage,PN SCR10K224, File No. 23-08-11-08
1. Need to update the Standard Notes. Old version of notes are on sheet CV-2,
newer version is given on sheet CV-3.
2. There is no filter stone barrier indicated around the pond outlet structure.
1.
2.
3.
4.
5.
6.
Cougar Estates,. PN SCR_1OJ817 _File No. 23-08-09-03
There are numerous typos in the narrative, of a type that could cause confusion
in interpreting the SWPPP.
The summary table on page 5 has no column headings.
Match lines on drawings do not match up from sheet to sheet.
Sheet C2.2 refers to the Detention Basin maintenance meeting the Pickens
County Stormwater Regulations. The basin is in Greenville County.
The Outlet Structure detail shows a 6" orifice where the hydrologic analysis
indicates a 2.5" orifice is needed.
The detention basin discharges at the property line, no 20' buffer is indicated.
Goodwin Farms, PN SCR10J143, File No. 23-08-05-22
l. The NOI is incorrect. Item IV.2.C.1 - the BIO impairment info is incorrectly
analyzed.
2. The supporting documentation is not bound & tabbed, & therefore difficult to
manage.
3. There is no legend on the plans.
4. The disturbed area is not delineated.
5. Proposed elevation contours are not shown.
6. Sedimentology is not discussed in the narrative. The Site Plan has sediment traps
discharging to wet detention ponds. This design is not supported in the
documentation. Maintenance of this design is not supported in the documentation.
7. Drainage Area Maps are not given for the sediment traps.
8. Sedimentology calculations use the 3 detention ponds for the calculations, but the
plan indicates the detention ponds are not to be used for sediment control after the
roads are built. The sedimentology of the traps is not discussed, and the drainage
areas for the traps are not delineated.
9. No road profiles are supplied
Assistant County Administrator’s
Response
• Will review its internal Plan Reviewer training
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requirements and make appropriate adjustments
Staff will hold joint training class with DHEC staff
to get better understanding of expectations
Provide staff with in-house refresher training and
incorporate the results from this audit report
Continually evaluate its construction plan review
program to find improvements
Impaired Water Response
• In an effort to aid the design community as well as
provide the County quantifiable assurances for meeting
MS4 permit goals, the County has developed and made
available the IDEAL computer program . With the IDEAL
model, the design engineer can calculate the annual
loading for the pollutant of concern for the predeveloped condition as a baseline and the developed
condition showing no increase for impaired waters
discharge compliance. The county intends to continue to
implement the program as it is referenced in the permit.
TMDL Compliance Response
• The waste load allocation percent reduction from
the first impaired station downstream of a
proposed project will be applied to the land
disturbance permit requirements. The applicant
will have to demonstrate with IDEAL that the
annual pollutant of concern loading for the site
in a developed condition will be reduced by the
respective amount as compared to the predeveloped condition.
Concerns or Questions
regarding IDEAL
Don Alexander, PE
Woolpert Consultants
Software Technical Support
Woolpert’s Internal Audit
• Consisted of two parts
– Evaluate original site county plan reviewed and
approved engineer design plan
– Field review to compare the design plans against
actual site implementation and to determine if the
EPSC features actually implemented were effective at
reducing erosion and sedimentation at construction
sites such that sediment was being retained to
achieve MEP
Sites selected
• 30 construction sites were selected
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12 single family
2 multi-family
11 commercial
5 industrial
The number of sites were randomly selected from
within each classification as determined using the
total population of active sites within each
classification and active at time of inspection
Plan Review Audit Results
• Summary of Most Common Plan Review
Deficiencies:
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Disturbed limits not shown
Soil type not denoted
No sequence bar chart
Lack of EPSC calculations
No drainage area specified for BMPs
Difficult to determine if BMPs sized properly
Lack of details for BMPs
Greenville County/adequate details not used
Field General Scores
• Common Issues at all 30 Sites
– No Design Plans Available
– No Inspection Logs Available
– No Stabilization of Inactive Areas
Field Review Results
• Summary of Most Common Field Review
Deficiencies:
– No geotextile layer in rock check dams and
construction entrances
– Lack of maintenance of BMPs
– Inadequate fabric height for silt fences
– Inadequate fabric depth for filter fabric inlet
protection
– Erosion and damage at outlets
– No protection provided at several inlets
Plan Review Conclusions and
Recommendations
• Add requirements to plan review checklist for
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sites that drain to impaired/303d/TMDL streams
Review CSPR and Internal Plan Reviewer training
materials and make appropriate revisions per
results of audit
Emphasize that EPSC Plans must include design
calculations for all EPSC BMPs
Recommend use of Greenville County details or
“equivalent” if available for a particular BMP
Plan Review Conclusions and
Recommendations
• Provide in-house refresher training for plan
reviewers to incorporate results of audit and
highlight most common plan review deficiencies:
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Lack of EPSC calculations
Disturbed limits not shown
No sequence bar chart
Soil type not denoted
Lack of standard details for BMPs
Greenville County standard details not used
Highlight specific BMP deficiencies
Field Inspection Conclusion and
Recommendations
• Provide in-house refresher training to incorporate results
of audit and highlight most common field inspection
deficiencies:
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Lack of inspection logs
Lack of filter fabric in appropriate BMPs
No project plans are kept on site
Improper site stabilization
Poor maintenance of BMPs
Inadequate fabric height for silt fence and depth for filter fabric
inlet protection
– Erosion and damage at outlets
– No protection provided at several inlets
Engineer’s Survey Results
• The majority still use some version of Hydraflow
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or Sedcad 4
Pre-Design meetings last too long and could be
limited to 30 minutes if all involved work briskly
through the checklist
Exempt owners from Pre-Design meetings if
they understand the process, owner
requirements and liabilities
50% would be in favor of having a credit card
option for fee payments
Engineer’s Survey Continued
• 60% are in favor of going to an electronic
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process if it saves time and resources thus
money to their client
71% who answered this question favored the
subdivision approval process being done
electronically
40% would be in favor of using the Charleston
approach to NOI and permit approval
Majority of the general comments were in
regards to our requirements being above and
beyond SCDHEC’s
Hydrologic and Hydraulic Software
• Staff heard that AutoCADD would no longer
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support Hydraflow
Based on survey results most still use some
version of this software
LDD will continue using Hydraflow and Sedcad
as the standard software we train our plan
review staff to know and use
We will continue to listen to the engineering
community on it’s ease of availability and
support from the software manufacturer
Pre-Design Meetings
• We will commit to continue the practice of scheduling
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the meeting to take place within 6 days from request
We will commit to keeping meeting times to no more
than 45 to 60 minutes in length
We will not over run the scheduled meeting time or
make the next appointment wait past their time
We will let the Design Professional do most of the talking
as they provide us with the needed information
regarding their proposed design
To meet our commitments the engineer must also
commit to …
Expectations of the Engineering
Community
• Provide options that will meet the county’s post
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construction water quality permit requirements
In order to receive a permit number at the conclusion of
the meeting be prepared with all specifics noted on the
next slide
Will not debate “Non-standard design manual
approaches” during meeting instead will require
proposed approach to go through the formal concept
review process
If specifics that meet the design manual are not met and
more discussion is needed with the time remaining the
meeting will become a development conference
Pre-Design Meeting Focus
• Design Professional will come to the meeting
prepared to explain how they will address in
their design the three major elements of permit
compliance
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Peak Rate Attenuation
Sedimentology
Post Construction Water Quality
Identify potential areas of off site impacts
Explain what parts of the site will require the most
attention to meet the requirements
Designer’s Preparation Prior to the
Meeting
• Familiarize yourself with the storm water permit
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requirements and design manual
Familiarize yourself with other local, state and federal
regulatory requirements and ordinances
Field visit of the site to understand existing site
conditions
Review project files for critical information if part of a
previously permitted project or larger common plan
Prepare a vicinity map with existing conditions and
proposed development plan
Identify potential storm water management features
Complete the Pre-Design Registry Form
Exempted Owners from Pre-Design
Meeting
• Will exempt developers/utility providers who
regularly work in construction and are aware of
EPA requirements
– Owner will still need to sign an acknowledgement
form (a tool in potential enforcement action)
– Signed acknowledgement will be included in submittal
package
– They will receive copy of Pre-Design summary form
outlining project scope, impacts and proposed
solution
Owner at Pre-Design Meeting
• Owners who’s primary business in not
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construction will be required to attend
Owner packet will no longer be explained in
detail just that it’s mandatory that they read and
understand their liabilities and responsibilities
If they have questions ask their design
professional to explain responsibilities
Signed acknowledgement form (which is used
for enforcement and magistrate fines) must be
included in the submittal package
County verses SCDHEC’s or other
Upstate City/County Requirements
• Greenville County is a Phase I MS4 permit
holder verses Phase II MS4 permit holders
– Phase I’s must meet higher standard for post
construction water quality
– IDEAL software model is how we meet this
higher standard requirements
– GC has had a permit since 2001 vs. 2007
– Phase II permit holders have not gone
through a SCDHEC audit yet
County verses SCDHEC or other
Upstate City/County Requirements
• We are guaranteeing a 10 work day plan
review turn around time vs. a 20 work day
turn around
• We are reviewing a higher volume of plans
verses these other local/MS4 agencies
• Need a standard format and software to
meet this guarantee
10 Business Day Turn Around
• Development Community desired a quicker turn
•
•
around time than required by state law
Construction Boom years coupled with limited
county manpower staffing made this difficult
Stakeholders group agreed that a standard
software and submittal package format would
allow staff to review plans quicker for permit
issuance
Times have Changed
The development community may
have different needs today than
10 years ago
Options for Plan Review Submittals
• If the development community feels that
engineering cost is a more important
factor than time we can offer alternatives
• Standard of 20 day turn around
• County’s Current 10 day turn around
• Expedited Review
State Standard 20 day turn around
• Pre-Design Meeting not required
• Engineer can submit using any software model of their choice
• Must provide a network diagram and pre and post maps as currently
•
•
•
•
required by SCDHEC
Use Standard SCDHEC checklist but with our 25 year storm design
standard
Must use IDEAL to meet our Phase I MS4 permit requirements for
post construction water quality
Must address Tree Ordinance and any other county related zoning
requirements specific to this project that effects land disturbance
This permit submittal option fee will cost $600 more than 10 day
turn around option since it will take additional staff time to perform
the needed sub-area delineation and verify travel paths, lengths,
slopes, etc
County’s Current 10 day turn
around
• Pre-Design meeting must be held
• Must use Hydraflow or SedCad software
• Must include the 360 area map with delineated
•
•
areas, CN’s, slopes, and flow path lengths
Must provide chart with input data to support
hydrology model & network diagram
Must address all the key information in the
narrative especially anything that outlines
master plan assumptions & how you will meet
water quality standards
Expedited Review
• Would mimic SCDHEC’s process and required fee
• Pre-Design meeting would be required prior to submittal
• Friday noon submittal deadline with paid $5000
•
•
•
•
additional expedited review fee
Monday morning 9:00 am meeting to review
Thursday morning 9:00 am meeting to discuss reviewer’s
comments
Friday 2:00 pm deadline for Engineer to address
comments and re-submit
Friday 5:00 pm County Plan Reviewer Preliminary
Approval
Concept Plan Process
• Use if proposing innovative design approaches not
•
•
•
•
currently in design manual or if deviations from the
design manual are proposed
Submit anytime after pre-design meeting with check for
staff review (the sooner in the process the better)
Staff will review within 10 days and share their findings
with County Engineer, who will make final decision on
approval
If approved the concept review fee will be subtracted
from the plan review fee
See section 3.1.4 of design manual for required
submittal data
Number of Permits Issued
• 2006/07 – 301 grading permits; 58 subdivision road
•
•
•
•
•
plans
2007/08 – 338 grading permits; 33 subdivision road
plans
2008-09 – 250 grading permits; 3 subdivision road plans
2009/10 - 253 grading permits(61 subdivision renewals);
2 subdivision road plans
2010/11 – 196 grading permits; 1 subdivision road plan
2011/12 (1st six months) – 95 grading permits;
0 subdivision road plans
Subdivision’s On-Hold/Re-permitted
(status since 10/7/09)
BUILDING CODES "HOLD" 12/6/11
Permit
Project Name
06-6476
SHEAD PROPERTIES (09-1241)
05-6326
PENNINGTON PARK
06-6508
ENOREE TRACE
06-6453
WETHERILL PARK
06-6566
NORTH RIDGE SUBDIVISION
06-6630
RIDGEWATER PH. 1
05-6197
BEAUMONT
07-6732
FURMAN PLACE
05-6077
BEL-AIRE COMMONS
07-6676
INGLES MARKETS
05-6161
HALTON MEDICAL
06-6582
GRIFFIN PARK (09-1247)
02-5153
VILLAGGIO DI MONTEBELLO
07-6673
VILLAGE @ WINDSOR CREEK
05-6072
LANDING @ SAVANNAH POINTE
05-6072
THE COVE @ SAVANNAH POINTE PH 1
06-6507
ELLINGTON PARK
05-6275
FIVE FORKS PLANTATION (10-1183)
07-6760
TUSCANY FALLS PH 1 (10-1023)
07-6762
HARRISON COVE (09-1256)
00-4464
WATTS/TRAVELERS RIDGE
04-5907
LENHARDT CREEK (11-1045)
07-6652
LAKE ROBINSON HEIGHTS/BLUE WATER
04-5827
LANSDOWNE (10-1019)
05-6314
WATERMILL (only certain lots) (11-1055)
04-5987
SHELLBROOK PLANTATION (11-1031)
05-6095
TAMARON PARK
04-5751
FAIRBROOKE
07-6736
THE RESERVE@GREEN VALLEY
06-6379
HUNTER RIDGE PH. IV
05-6180
WINDSOR CREEK
06-6543
SOUTHSIDE ESTATES
06-6552
RIVERBEND ESTATES (10-1010)
06-6435
BRUTONTOWN PH. 1-A (10-1007)
05-6343
LADSON LAKE
05-6141
PLANTATION GREEN PH. II (10-1035)
04-5783
ASHMORE SPRINGS PH. 3
07-6939
MCRAE PARK (11-1120)
07-6883
THE GARDENS @ ROSE RESERVE (10-1033)
05-6305
HOLLINGTON
07-6695
KILGORE FARMS - PH.4 (10-1036)
06-6358
HAWTHORNE RIDGE
06-6370
CLEAR SPRINGS
05-6054
PELHAM VILLAGE (FKA VILLAS OF TOSCANO)(11-1133)
05-6203
CEDARCREST/GREYTHORNE (11-1078)
04-5745
BARNETT VALLEY
06-6428
CARDINAL CREEK TOWNHOMES (11-1175)
05-6075
GILDER CHASE (09-1239)
05-6188
VALLEY VIEW/SUMMIT (09-1118)
01-4973
PONDICHERRY/CITY LIGHTS (10-1043)
07-6746
COURTYARDS @ WEST GEORGIA
06-6465
WILLIMON ESTATES(FKA WILLIMON PLACE)
PROJECTS SUBMITTED FOR RENEWAL/CLOSEOUT
INSP
QM
JB
JB
QM
JB
JF
DS
DS
DS
DS
JS
JF
DS
JS
JS
JS
JS
JS
JS
JS
DS
DS
JB
JF
JF
JS
TR
JF
DS
DS
JS
QM
JB
DS
QM
TR
JF
JS
JB
JS
JS
TR
TR
TR
JF
JB
TR
JS
JB
JF
QM
DATE SENT TO CODES
10/6/2009
10/6/2009
10/6/2009
10/6/2009
10/6/2009
10/7/2009
10/7/2009
10/7/2009
10/7/2009
10/7/2009
10/7/2009
10/7/2009
10/7/2009
10/9/2009
10/9/2009
10/9/2009
10/9/2009
10/9/2009
10/9/2009
10/9/2009
10/13/2009
10/13/2009
10/13/2009
10/13/2009
10/29/2009
10/29/2009
11/16/2009
12/22/2009
12/22/2009
12/22/2009
12/22/2009
12/22/2009
12/22/2009
12/22/2009
12/23/2009
12/28/2009
1/29/2010
1/29/2010
1/29/2010
1/29/2010
1/29/2010
1/29/2010
2/1/2010
2/1/2010
2/1/2010
2/5/2010
4/26/2010
5/10/2010
6/2/2010
7/20/2010
11/2/11
12/6/2011
DATE RELEASED
12/18/2009
closeout 10/27/11
closeout 4/12/10
closeout
closeout 11/9/11
closeout 10/21/10
closeout 11/9/11
9/7/2010
11/5/2010
12/29/2010
3/23/2011
2/15/2010
3/15/2011
close out 10/27/11
9/9/2011
3/11/2010
5/16/2011
6/6/2011
close out 10/27/11
1/26/2010
2/19/2010
3/29/2010
10/14/2011
4/1/2010
8/10/2011
3/2/2010
11/4/2011
6/29/2010
Average Turn Around
(We have one of the shortest turn around commitments in
the Upstate)
• 2010/11
– 1st Submittals – 7.38
days
– Re-submittals - 3.9
days
– Modifications - 6.47
days
• 2011/12 (1st six mo’s)
– 1st Submittals – 6.27
days
– Re-submittals – 3.50
days
– Modifications – 7.18
days
SCDHEC NOI Applications
• Greenville County LDD’s processing of NOI application &
•
•
•
forwarding to DHEC along with our approval form is a
courtesy & not a requirement of state law
Survey says Engineer’s want to maintain this practice vs
getting NOI approval first or Engineer filing the NOI
directly to DHEC after our preliminary approval.
DHEC has outlined their expectation regarding the
completion of their application. We review the
application to assist the engineer in identifying items
that could delay it’s approval.
LDD does not have the authority to change, modify or
add to this application.
EPA’s definition of “part of a larger
common plan”
• Large Construction Activity – development or
•
•
sale that will ultimately disturb equal to or
greater than five (5) acres
Small Construction Activity – results in land
disturbance of equal to or greater than one acre
and less than five acres
EPA & DHEC has stated NOI coverage is
required even if disturbing less than one acre, if
included as part of a large common plan of
development where ultimately disturb equal to
more than one acre but less than five (5) acres
EPA’S Broad Definition
Part of Larger Common Plan
• Any announcement or piece of
documentation (including a sign, public
notice or hearing, sales pitch,
advertisement, drawing, permit
application, zoning request, computer
design) or physical demarcation (including
boundary signs, lot stakes, surveyor
markings) indicating construction activity
may occur on a specific plot
Common Plan of Development or
Sale
• Is a contiguous area where multiple, separate & distinct
•
•
construction activities may be taking place either
simultaneously or on different schedules
This includes activities scheduled to occur in “phases”
SCDHEC considers it to be part of a LCP if there has
been land disturbance activities (clearing, grading or
excavating) resulting in an accumulation of 1 or more
disturbed acre since 1992 or will exceed the 1 acre limit
with future land disturbing activities
County Defined verses SCDHEC
• Any larger common plan that has no
active construction and/or was not
previously permitted under a general
construction permit by SCDHEC but is
documented as being previously permitted
by Greenville County and is in LDD’s
database
Engineering Minimum Plans
• Are used when the project scope size or runoff increase
•
•
•
doesn’t qualify under the non-simplified requirements
but requires the expertise of an engineer
Engineer certification or supervision of work needed due
to changes to the drainage system, environmentally
sensitive downstream conditions or stabilization plan
needed for sites disturbed w/out permits & under NOV
Project minimally exceeds simplified criteria in size or
runoff increase where LID’s will be used to meet
requirements
Project is simplified in scope or size but is part of a site
defined by SCDHEC or LDD as a part of a larger common
plan
Engineer Supervision
• Site requires periodic observation of construction
•
•
•
& a final inspection for design compliance
Project does not warrant CEPSCI inspection level
oversight
Engineer defines the frequency of site visits and
the general nature of his/her oversight
This inspection can be made by a representative
of his/her office under engineer’s supervision
Low Impact Development
Requirement (Green Infrastructure)
• Rezoning to higher density to meet the
Centers and Corridors plan would need to
use LID’s to meet water quality standards
• Changes to LDR will incorporate the use of
LID’s in road right of way applications
• Details are being sought from other
agencies – PDF and CADD formats will be
provided for engineer’s use
Steep Slope/Mountainous Grading
Requirements
• Traditional engineering designs to meet storm
•
•
water management are difficult in mountainous
terrain
To meet requirements 65 percent of the site
should be preserved in a forested or native soil
and the effective imperious surface of the area
must be <10%
Runoff from imperious area must drain to native
buffer areas or into an LID feature
Small Residential Subdivisions
• Full Dispersion or Partial w/ LID features (when
•
•
•
over 50% is lawn) instead of Detention facility
Use in Subdivisions being created by Summary
Plat
Use when dividing one parcel into two
Use in small subdivision developments where a
common area is not feasible and/or HOA will not
have the legal or financial ability to maintain a
common area with a traditional storm water
management facility
Ratio for effective impervious areas
% Native
Vegetation
Preserved
(min. allowed)
65
% Effective
Impervious
(max. allowed)
10
% Lawn/Landscape
(max. allowed)
35
60
9
40
55
8.5
45
50
8
50*
45
7
55*
40
6
60*
35
5.5
65*
Infiltration Basin Requirements
• Not applicable in industrial and commercial areas where
•
•
•
•
•
solvents, petroleum or pesticides are loaded, unloaded,
stored or applied
Provide data that soils are not >20% clay & <40%
silt/clay. Clay soils are not conducive to infiltration
Double-Ring test for infiltration must be perform by
geotechnical engineering firm and sealed by a PE from
that firm
Infiltration rates must be between .5 & 3 in/hr
Infiltration basins have a high failure rate due to
improper siting, design and lack of maintenance
Must meet all criteria outlined on LDD’S new checklist
Mechanical Water Quality Device
Policy
• On current approved list (Appendix G)
• If not, provide the device’s pollutant efficiency
•
•
data approved by EPA ETV or NJCAT programs
Use efficiency data as input data for IDEAL to
prove required removal efficiencies for pollutant
of concern
Devices will be approved on a site by site basis
with IDEAL’s adequate removal demonstrated
Staff Request for Consideration
• 360 map – small scale and color on top of color is
•
•
•
•
•
difficult to read (especially yellow & green)
Similar line types used on small drawings are difficult to
read
Each firm uses different legends markings for similar
items such as retaining walls
Inspectors rely on the “site map” on plans to find the
site location – please make sure to include
Quantities need to be field measured for accuracy on
letters of credit & roadway acceptance certifications
Stormwater facilities need volume capacity verified
earlier in construction during grading operations
Permit Extension Joint Resolution of
2010 (H4445)
• For development approval that is current
and valid at any point during the period
beginning January 1, 2008 and ending
December 31, 2012, the running of the
period of the development approval and
any associated vested right is suspended
during the period beginning January 1,
2008 and ending December 31, 2012
Grading Permit Renewal beginning
2013
• July 2012 – Inspection staff will categorize current
permitted sites
– Subdivisions that have reached 50% build out and need
certifications and pond acceptance documents
– Subdivisions that need to renew (not 50% yet)
– Sites that are substantially complete, need stabilization letter
and close out documents
– Active Sites that need to renew
– Inactive Sites that need to be stabilized and permit voided
– Sites that were never started and permit voided
– Permitted sites that do not need renewal in the first 6 months of
2013
2012 Permit Renewal Process
• Letters will go out by September giving
•
•
developers 3 months to stabilize & close based
on 50% build out or renew their permits
Engineer of Record will be copied
Unresolved sites compliance will have permits
revoked, holds placed on building permits and
possible citations and civil penalties depending
on the condition of site
SCDHEC’s 2012 General
Construction Permit Requirements
• The public notice period has closed
• Currently being edited based on
comments received during notice period
• Anticipated date for issuance is this Spring
• LDD Staff is reviewing permit application
forms, checklists & current procedures for
possible changes to meet the new
requirements
SCDHEC’s 2012 General
Construction Permit Requirements
• Secondary Permittee – Home Builders, Individual
•
•
•
•
Lot Owners, Contractors and possibly Utility
Providers
Contractor Certification forms must be on site
Utility Providers may obtain from DHEC a
blanket notice of intent
Individual Lot NOI will be required (plat, plan or
map needed)
Primary’s SWPPP must outline if Secondary will
adhere to the SWPPP or develop their own
General Construction Permit
Requirements Continued
• Ongoing Project (2006 GCP)
– May be asked to confirm intent to be covered
– If requested, must provide w/in 30 days
– If not confirmed coverage is terminated
– Must modify current SWPPP to add Section
3.1.1F no later than 6 month after new permit
General Construction Permit
Requirements Continued
• Section 3.1.1 F
– Add appendix for progress reports, compliance and
modification
– Revise SWPPP to address non-numeric effluent limits
unless specifically excluded
– Change frequency of site visits to weekly
– Add Rain Log appendix
– Add Inspection Log appendix
– Qualified Inspector can not be direct employee of
contractor
General Construction Permit
Requirements Continued
• Ongoing Project (1998 GCP)
– Must comply with Section 3.1.1 F
– Must have a permanent maintenance
agreement
General Construction Permit
Requirements Continued
• New Owners of Previously Permitted Sites
– Must notify w/in 14 calendar days with project name,
initial permittee NOI tracking number
– If completely stabilized and inactive 14 days does not
apply
– If inactive but not completely stabilized must obtain
NOI and develop stabilization plan
– If complying with existing SWPPP transfer NOI
– Completed NOI must come with G’ville Co approval
letter stating that the construction is consistent with
all requirements of this permit
General Construction Permit
Requirements Continued
• On-site SWPPP
– Living document w/modification and record logs
– Kept on-site until final stabilization
– Notice on-site of plans location with updated contact info posted
near main entrance (if no personnel present)
– Contractors and Builders w/day to day operations must have a
copy of the on-site SWPPP at central location by identifying
responsibility
– Copy sent to DHEC’s regional office for linear projects
– Must be made available upon request
– Created after NOI coverage is granted
General Construction Permit
Requirements Continued
• On-Site SWPPP contents
– Copy of Comprehensive SWPPP (excluding
engineering report)
– SCDHEC General Construction Permit
– NOI letter (stamped and approved)
– NPDES Coverage Approval letter
– Local Approval
– USACOE Approval (if applicable)
– Contractor Certifications
– Record Keeping (Pre-Con log, Inspection log,
Stabilization log, Rain log & Contractor log)
General Construction Permit
Requirements Continued
• Defines Major and Minor Modifications
– Major (significant changes in design,
construction, operation or maintenance that
reasonable potential to cause or contribute to
violations of SC Water Quality standards)
– Major changes must go back to regulating
agency for review and approval
– MS4 is given authority to determine if SWPPP
is ineffective & that modifications are needed
General Construction Permit
Requirements Continued
• Major Modifications include:
–
–
–
–
–
–
Resizing sediment/detention basins
Deletion of sediment traps/detention basins
Relocation of sediment traps/detention basins
Addition of sediment traps/detention basins
Modifications to outlet structures of basins
Changes in grading that alter drainage patterns that
increase/decrease flow to traps/basins
– Amending construction sequence that basins are not
installed before grubbing operations
General Construction Permit
Requirements Continued
• Major Modifications involving Point Discharge or
outfall locations changes include:
–
–
–
–
–
Modifications to regulated WQ structure
Adding new point discharge
Adding impervious or disturbed area
Navigable water crossing changes
Site layouts that require redesigning storm water
management conveyance systems
– Adding sediment traps
General Construction Permit
Requirements Continued
• Minor Modifications (Changes can be
made to on-site SWPPP only)
– Adding ECSC BMP’s (if no wetlands involved)
– Relocating ESSC BMP’s
– Removing disturbed areas
– Individual lot drainage modifications
General Construction Permit
Requirements Continued
• SWPPP Content – Narrative
– Scope of Project w/ detailed description pre & post
condition
– Description of existing flooding problems on-site or
surrounding areas
– Required on-site support activities (concrete or batch
plants)
– Identification of prior uses of the site, potential
sources of pollution & how it contributes to WQ
standard violations
– Identify industrial stormwater discharges that will be
on the site
General Construction Permit
Requirements Continued
• SWPPP Contents
– Specifically state that “impervious surfaces for
stabilization should be avoided” as Erosion Prevention
BMP
– Identify and describe measures to prevent the
discharge of building and construction debris
– Identify all potential sources of pollution (sediment,
fertilizers, etc)
– Detention/Retention Ponds design refer to 72.307
General Construction Permit
Requirements Continued
• SWPPP – Sequence of Construction
– >5 acres must have phased erosion control plan for
each phase having a specific sequence of construction
– Sequence must be include on construction site plan
• Must begin w/ construction entrance and perimeter control
• End w/ temp sediment & erosion control measures
• Conversion of BMP to permanent control
• Level of detail vary based on complexity of project
General Construction Permit
Requirements Continued
• SWPPP Content – Sensitive Areas
– Must identify all Waters of the State, Wetlands w/in
disturbed areas, total area and if immediately
adjacent.
– Identify receiving waters
– Must show all Waters of the State on separate plan
sheet if w/in construction site
– Must identify all impacted areas by outlining and
labeling that no work can begin until COE &401
obtained
– If structural BMP is proposed w/in Waters of the state
must meet section 3.2.6.A.V
General Construction Permit
Requirements Continued
• SWPPP – Buffer Zone Preservation
– When waters of the state are located on or
immediately adjacent to the construction site
• Identify and preserve an undisturbed vegetated
buffer during construction
• 30’ Buffer minimum between waters of the state
• 45’ Buffer around high class water or impaired
waters
• Additional local requirements may apply
General Construction Permit
Requirements Continued
• SWPPP – Buffer Zone Preservation
– All discharges though the buffer must be nonchannelized and/or non-concentrated
– Must first be treated by the construction site’s
sediment and erosion controls BMP’s
– Special circumstances may allow work in the
buffer if all disturbed areas above have
reached final stabilization and work will not
cause violation of water quality standards
General Construction Permit
Requirements Continued
• SWPPP – Buffer Zone Preservation
– If buffer is unattainable the SWPPP must identify and
require the implementation of sediment and erosion
control that will prevent the discharge of sedimentladen stormwater
– Must provide a written waiver with justification and
supporting documentation
– Additional BMP’s that surpasses the regular standards
– Maintenance Agreement during construction with
outline of detailed plan for each BMP
– Letter from the permitting agency (ie: GC LDD)
– DHEC must approve all written variance requests
General Construction Permit
Requirements Continued
• SWPPP – Buffer Zone Preservation
– Certain types of construction activities are
exempted
• Water, Sewer, Utility, and Roadway construction at water
crossing
• Construction of water-dependent structures and access areas
• Development of a site where no naturally vegetated buffer
area existed prior to the construction project
• Construction sites previously covered under 2006 GCP
General Construction Permit
Requirements Continued
• SWPPP Content – EPSC BMP’s
– Accurately and descriptively address the use,
installation, maintenance and inspection of the EPSC
BMP’s
– Compute only # of acres draining to sediment basin
that are disturbed
– Use porous baffles in temp. sediment traps and
sediment basins (unless infeasible)
– Sediment traps must be used if draining > 2 acres but
< 5 acres
General Construction Permit
Requirements Continued
• SWPPP Content – Runoff Control
– Permanent Conveyance Measures must
handle the 10 yr – 24 hr storm and must be
<5 fps. If >5 fps must reduce velocity to nonerosive or use liner to reduce erosion
– Temporary Conveyance channels must divert
concentrated flow of stormwater running to it,
on to the site and stabilize these w/in 7 days
General Construction Permit
Requirements Continued
• SWPPP Content – Post Construction WQ
– Development condition must not cause or contribute
to violations of WQ standards
– Non-Structural BMP’s must be designed, installed and
maintained to maximum pollutant removal
– LID BMP’s must be installed only after areas are
stabilized
– Design, Inspect and maintain BMP’s in SWPPP at a
minimum consistent w/ design manual
General Construction Permit
Requirements Continued
• SWPPP – Maps
–
–
–
–
–
–
Show overlaying contours of the site & surrounding areas on topo map
Include names of each soil types on soil map
Each floodplain must be clearly identified
Vicinity map must include a north arrow
Drainage map needed for pre & post developed conditions & contours
Drainage basins & sub-basins where stormwater runoff collects & drains
to a common outfall
– Include offsite areas draining onto the site
– Drainage maps must be consistent w/ the info provide in all calculations
provided in the report
– Drainage Map for each BMP to meet WQ (outline drainage basin for
proposed BMP’s, location of each proposed BMP & area in acres to each
General Construction Permit
Requirements Continued
• SWPPP Content – Engineering Report
– Stable Channel Analysis to ensure non-erosive
– Storm Sewer Analysis
– Rip Rap Apron Analysis
General Construction Permit
Requirements Continued
• SWPPP – Engineering Report
– Permanent WQ analysis w/ detailed
calculations for any structural BMP
– Sedimentology (trapping efficiency analysis)
detailed calculations for any BMP used to
meet WQ requirements
– As-built survey required if directing runoff to a
previously approved detention pond unless
as-built has been provided and accepted
General Construction Permit
Requirements Continued
• SWPPP – Detention As-built Data
– All existing grades/contours/depth of pond
– Invert diameters, elevations & dimensions of
all outlet structures (pipes, orifices, weirs,
risers & emergency spillway)
– Location & inverts for all pipe discharging into
the pond
General Construction Permit
Requirements Continued
• SWPPP – Construction Plans
– Must be consistent w/ 72-307.A.3
– Detailed EPSC Plan sheets including, grading
and drainage plan and BMP detail sheet
General Construction Permit
Requirements Continued
• SWPPP Content – Phased EPSC Plan
– Each Phase must be on a separate plan sheet and
one sheet w/all the details
– Non-linear sites disturbing >10 must have at least a 3
phased EPSC plan
• Initial/major grading
• Construction interim (temp BMP’s to convey, manage, treat)
• Final Contours (stabilization plan)
– Non-linear sites disturbing <10 acres must have at
least a 2 phased EPSC plan
• Initial/major grading
• Final Contours (stabilization plan)
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Control Stormwater volume and velocity w/in
site to minimize erosion
• Volume (limit amount disturbed, phasing,
terracing, diverting offsite flow, controlling
drainage patterns)
• Velocity (surfacing roughening, sediment traps,
temp seeding, blankets, TRM, BFM, riprap, polys)
General Construction Permit
Requirements Continued
• SWPPP – Non-Numeric Effluent Limits
– Control Stormwater discharges to minimize
erosion at outlets, downstream channels &
streambanks
• Volume discharge control (Hydrology, surface
outlets, WQ storage w/in impoundments)
• Peak rate discharge (energy dissipaters, level
spreaders, riprap aprons, blankets, TRM)
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Minimize Amount of Soil Exposed
• Phased EPSC plan that limits amount of exposed
soil
• Outline the limits of disturbance on plan
• Stabilize exposed area ASAP
• Implement temporary seeding
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Minimize the disturbance of steep slopes
(15% and greater)
• Divert flow around steep slope disturbance
• Use specialized control for steep slopes (mattings,
blankets, pipe slope drains, seep berms)
• Stabilization ASAP after disturbance (no later than
7 days) & w/in 3 working days of stabilization
efforts must have vegetation cover & installed nonvegetation cover
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Minimize sediment discharges from the site
during construction
– Maintain natural buffers around surface
waters
– Direct stormwater to vegetated areas to
maximize infiltration during construction
– Minimize soil compaction and preserve topsoil
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Stabilize soil w/in a time period as determined
by the permitting authority. Mulch and other
temp measures should be used when
vegetation stabilization in not immediately
feasible
– Discharges from dewatering are prohibited
unless managed by appropriate controls
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Minimize discharges of pollutants during
construction
• Equipment/vehicle washing, wheel washing &
other wash waters (must be treated in a sediment
trap)
• Exposure of building material/products,
construction waste, trash, landscape, detergents,
sanitary waste, fertilizers, herbicides
• Spill & Leak prevention plan & response procedure
General Construction Permit
Requirements Continued
• SWPPP – Non-Effluent Limits
– Prohibited Discharges
• Washout of Concrete
• Washout of paints, oils, stucco, curing compounds
• Fuels, oils & other vehicle/equipment maintenance
material
• Soaps & solvents in washing
General Construction Permit
Requirements Continued
• SWPPP – TMDL
– If TMDL applicable to stormwater construction
discharges have been established in receiving waters
must incorporate measures or controls that are
consistent with TMDL
– If specific waste load allocation has been established
to discharge must incorporate that allocation into
SWPPP (IDEAL)
– 303(d) for sediment, BIO,TP & TN
• Carefully evaluate all selected BMP’s & their performance
• >25 acres must be a written quantitative and qualitative
assessment (IDEAL)
General Construction Permit
Requirements Continued
• Implementation, Inspection &
Maintenance
– Pre-Construction Conference
• Linear (Stand Alone) Construction Projects
– Can conduct conference offsite w/ each contractor
• Non-linear construction disturbing 10 acres & >
– Primary or Secondary Permittee must conduct
conference w/ each contractor or builder who is not a
permittee on site
General Construction Permit
Requirements Continued
• Implementation, Inspection & Maintenance
– Pre-Con’s Purpose
• Preparing of the SWPPP, Equivalent Registration or the
•
•
•
•
Person w/ operational control of the plans to explain the
entire SWPPP to the contractors & builders
Specifically go over the areas of the SWPPP that relates to
the work performed by them
Must address how modifications (major/minor) to the plans
will be addressed and processed at the construction site to
maintain compliance
Meeting must be documented w/in the On-Site SWPPP
(dates, locations, times, attendance)
Document meeting to complete contractor certification form
General Construction Permit
Requirements Continued
• Inspections
– Scope (all disturbed areas, perimeter BMP, exposed material storage
areas, evidence of potential pollutants entering conveyance system,
discharge locations, EPSC measures, vehicle access point, inefficiencies
w/in BMP’s)
– Frequency (minimum once every week, once finally stabilized definable
area can be marked off on-site SWPPP)
– Rain Gauge (maintain on-site gauge or use data from certified weather
record w/in reasonable proximity, record rainfall events .5” &>, must
maintain in rain log in on-site SWPPP)
– Inspector Qualifications (can not be a direct employee of any contractor
responsible for activity covered by the inspector, for projects > 2 acres,
for 2 acres & < permittee may perform inspections provided the
preparer of SWPPP explains the SWPPP implementation & inspection
requirements)
– Monthly Reports (DHEC may require on case-by-case basis submitted
monthly reports)
General Construction Permit
Requirements Continued
• Maintenance
– Permittee must address the necessary replacement or
modification required to correct BMP w/in 48 hrs of
identification
– Sediment must be removed when deposited sediment
reaches 1/3 height of the BMP
– A detailed permanent maintenance plan must be
outlined in the narrative
– Agreement and maintenance plan must be in the
SWPPP
General Construction Permit
Requirements Continued
• Maintenance Agreements
– Signed notarized agreement from responsible
party for each of the permanent WQ features
– MS4 must be notified in writing of any
changes in the maintenance responsibilities
– Construction sites originally permitted under
1998 GCP must sign notarized maintenance
agreement
General Construction Permit
Requirements Continued
• Secondary Permittees are responsible for either
•
maintaining or coordinating the maintenance of
Common BMP’s which accept storm water
discharge from any areas associated with their
work with the Primary permittee
Maintenance Plans Content
– Description of maintenance plan used
– Manufactured devices must have detailed procedures
for maintenance included in plan
– Each WQ feature must have maintenance activity
described for all items of feature
General Construction Permit
Requirements Continued
• Termination of Coverage (NOT)
– Can submit only if one or more below exist
• Final stabilization has been achieved on all portions of the
•
•
•
•
site for which permittee is responsible
Another operator has assumed control over all areas not
finally stabilized
Individual Lot Coverage or Alternate General NPDES permit
has been obtained
For residential subdivision lot temp stabilized and lot
ownership transferred to homeowner
Land disturbance was never initiated on the site and the site
remains permanently stabilized
General Construction Permit
Requirements Continued
• Notice of Termination (NOT)
– DHEC must receive letter from MS4 that site meets
criteria to terminate permit
– If ownership or maintenance of permanent WQ
features have change since original approval copy of
revised agreement must be attached
– Primary Permittee’s in residential subdivisions can
request NOT when Secondary Permittees are
authorized to conduct construction activities for the
remaining disturbed areas of the construction site and
final stabilization has been achieved on all other area
of the site.
EPA’s Permit Requirements
• Stormwater Regulations
– Original Deadline was September 30, 2011
– Extended to December 30, 2011
– Negotiating with Chesapeake Bay Foundation due to
lawsuit filed & current delays
– Additional cost-benefit data need
– Proposed regulations new date for release is
December 2012/Janaury 2013
– New deadline for implementation later in 2013
EPA’s Permit Requirements
• National Effluent Standards (Turbidity)
– Deadline delayed to obtain better scientific data
– January 3, 2012 notice requesting more data
• Effectiveness of technologies in controlling
turbidity
• Seeks comments on passive treatment data
already available
• Dr. Barfield to summarize research authorized last
year by Greenville County
• 60 day comment period established for this
request
SCDHEC’s Permit Renewals
• DHEC was waiting for the new EPA
proposed regulations to ensure Phase II
permit regulations were “in line” with new
standards
• With EPA’s delay until 2013 it is believed
that DHEC will go ahead and issue both
Phase I and Phase II renewal permits
Greenville County’s 3rd Cycle
NPDES Phase I MS4 Permit
• Our current MS4 permit expires July 1,
2012
• We submitted our renewal permit
application on December 29, 2011
• Some changes expected in our permit
requirements
• Increased compliance for watersheds with
TMDL designations
Possible requirement changes
• Review of local codes and land
development requirements to reduce
storm water impacts of new development
and significant redevelopment
– Mandate LID principals in specific applications
– Reduction in impervious surfaces
– Reduction of flow and volume
– Increase or mimic natural hydrology
303(d) and TMDL Compliance
• Engineer will need to use IDEAL to model pre
•
and post construction water quality for identified
pollutant for numeric quantification.
For TMDL watersheds with waste load allocation
percentage reduction requirements the site will
need to be designed to show in IDEAL that the
percentage reduction was achieved on site
Reedy River Nutrient TMDL
• Will required the pre and post construction
•
•
•
•
IDEAL model runs
May require use of Green Infrastructure or
disturbance thresholds
May require more stringent buffer widths and
requirements
May require stream stabilization or restoring
buffers in conjunction with site improvements
Increased education of HOA and in common
areas on pet waste & maintaining buffers/LID’s
Thank You for your
Attendance
Questions?