1. District Drainage Engineer Northern Virginia District
Pawan Sarang, P.E.
District Drainage Engineer
Northern Virginia District
May 18, 2011

2. VDOT - Stormwater Management Requirements Update

3. Virginia Stormwater Management Law is codified in Title 10
Virginia Stormwater Management Law is codified in Title 10.1, Chapter 6 of the Code of Virginia and the Virginia Stormwater Management Regulations are found at Chapter 60 and Chapter 30 of the Virginia Administrative Code (4VAC , 4VAC , 4VAC , 4VAC & 4VAC ). The Law and Regulations together provide the authority and the technical criteria for the Virginia Stormwater Management Program (SWM Program). VDOT is a MS-4 Permit Holder and executes Annual Agreement for its Standards and Specifications with DCR which includes SWM Program and Erosion and Sediment Control Program. DCR reserves the right to randomly select projects for review (in either the design or construction phase) to ensure compliance with the VDOT approved Program.

4. The Virginia Stormwater Management Regulations are applicable to all Regulated Land Disturbance Activities (RLDA) undertaken by or for VDOT including, but not limited to projects and activities developed under the following plan processes:
RAAP
SAPP
Minimum
No Plan
PPTA
Design Build
Capital Outlay
Rural Rustic
Non Routine/Routine Maintenance Activities *
All routine maintenance activities exempted by 2011 G.A.
changes to the VSMP Law (Section )

5. Land Disturbance (as defined in the VSMP Regulations):
A manmade change to the land surface that potentially changes its runoff characteristics including any clearing, grading or excavation associated with the proposed activity
Grading of gravel surfaces to maintain travel way generally exempt *
Pavement milling and/or overlay generally exempt *
* Changes by the 2011 G.A to the VSMP Law (Section ) classifies paving an impervious surface and the associated shoulder and ditch restoration as routine maintenance activities and, therefore, exempt from
VSMP Regulation requirements.

6. Current SWM Requirements
SWM Requirements are applicable for those regulated land disturbance activities that disturb one acre or greater except in those areas designated as a Chesapeake Bay Preservation Area in which case the land disturbance threshold is 2500 square feet or greater.
The following land disturbance activities are exempt for the VSMP Regulations for linear development projects (i.e., highway construction projects) where all the following conditions are met:
Less than one acre will be disturbed per outfall or watershed.
There will be insignificant increases in peak flow rates downstream of the discharge point.
There is no existing or anticipated erosion problems downstream of the discharge point.
There is no existing or anticipated flooding problems downstream of the discharge point.
Typically applied on an outfall by outfall basis
Routine maintenance that is performed to maintain the original line and grade, hydraulic capacity or original construction of the project and which disturbs less than five acres of land.

7. Current SWM Requirements
As part of VDOT Annual Agreement with DCR, following are design criteria addressing water quality under VDOT SWM Requirements:
Using Technology Approach:
1. Base the percent impervious cover on the entire post construction impervious area within the right of way plus permanent easement area per outfall.
2. Determine the required BMP based on the percent impervious calculated from No. 1 above.
Using Performance Approach:
Design the BMP for a water quality volume based on the net increase in impervious area plus 10% of the pre-construction impervious area. The goal is to determine BMP that would remove pounds of phosphorus to 10% less then existing loading.
Water quantity control shall be governed by the Virginia Erosion and Sediment Control Regulation Minimum Standard - 19 (MS-19) that requires an adequate receiving channel for stormwater outfalls

8. WATER QUALITY ANALYSIS LINEAR DEVELOPMENT PROJECTS (BASED ON AN INDIVIDUAL OUTFALL ANALYSIS)
TECHNOLOGICAL BASED CRITERIA
Step 1 – Is there one acre or more of land disturbance within the site draining to the
outfall?
Yes – Not Exempt - Go to Step 5
No - Go to Step 2
Step 2 - Is the land disturbance activity generating a significant increase in discharge
downstream of the outfall point? (Note: The adequacy of the downstream channel
to accommodate any increased discharge without causing flooding and erosion
problems can be used as one measure of whether or not there is a “significant”
increase in discharge.
Yes – Not Exempt – Go to Step 5
No – Go to Step 3
Step 3 - Is there existing or potential flooding issues downstream of the outfall point?
No – Go to Step 4
Step 4 - Is there existing or potential erosion issues downstream of the outfall point?
No – Outfall exempt – Go to Step 1 for next outfall
Step 5 - Determine pre-developed impervious area within the site draining to outfall.
Step 6 - Determine post developed impervious area within the site draining to outfall.
Step 7 - Determine net increased impervious area within the site draining to outfall:
Step 6 answer minus Step 5 answer

9. WATER QUALITY ANALYSIS LINEAR DEVELOPMENT PROJECTS (BASED ON AN INDIVIDUAL OUTFALL ANALYSIS)
Step 8 – Is Step 7 answer zero or a negative number?
Yes – Outfall exempt – Go to Step 1 for next outfall
No – Go to Step 9
Step 9 – Determine the post development site area of the site draining to the outfall.
Step 10 - Determine percent impervious of the site:
Step 7 answer divided by Step 9 answer
Step 11 – Is the Step 10 answer 16% or greater?
Yes – Go to Step 12
No – Outfall exempt – Go to Step 1 for next outfall
Step 12 - Determine required BMP from BMP Table based on percent impervious from Step 10 (this time from Total Impervious Area draining to outfall)
Step 13 - Determine WQV:
Step 6 answer times 0.5”
Step 14 - Determine BMP volume:
Step 13 answer times appropriate value for the selected BMP
Step 15 – Go to Step 1 for next outfall.

10. WATER QUALITY ANALYSIS LINEAR DEVELOPMENT PROJECTS (BASED ON AN INDIVIDUAL OUTFALL ANALYSIS)
PERFORMANCE BASED CRITERIA
Step 1 – Is there one acre or more of land disturbance within the site draining to the
outfall?
Yes – Not Exempt - Go to Step 5
No - Go to Step 2
Step 2 - Is the land disturbance activity generating a significant increase in discharge
downstream of the outfall point? (Note: The adequacy of the downstream channel
to accommodate any increased discharge without causing flooding and erosion
problems can be used as one measure of whether or not there is a “significant”
increase in discharge.)
No – Go to Step 3
Step 3 - Is there existing or potential flooding issues downstream of the outfall point?
No – Go to Step 4
Step 4 - Is there existing or potential erosion issues downstream of the outfall point?
No – Outfall exempt – Go to Step 1 for next outfall
Step 5 – Determine the post development area of the site draining to the outfall.
Step 6 - Determine pre-developed impervious area from the site draining to outfall.
Step 7 - Determine post developed impervious area from the site draining to outfall.
Step 8 – Determine pre-developed percent impervious of the site:
Step 6 answer divided by the Step 5 answer

11. WATER QUALITY ANALYSIS LINEAR DEVELOPMENT PROJECTS (BASED ON AN INDIVIDUAL OUTFALL ANALYSIS)
Step 9 – Determine post developed percent impervious of the site:
Step 7 answer divided by the Step 5 answer
Step 10 - Is the Step 8 answer 16% or less and the Step 9 answer less than 16%?
Yes – No reduction in post development pollutant load required – Go to Step 1 for next outfall.
No – Go to Step 11
Step 11 - Is the Step 8 answer 16% or less and the Step 9 answer greater than 16%?
Yes – The post development pollutant discharge shall not exceed the pre-development pollutant discharge based on 16% imperviousness. Go to Step 14
No – Go to Step 12
Step 12 - Is the Step 8 answer greater than 16%?
Yes – Go to Step 13
No - Go to Step 10
Step 13 - Determine WQV:
Step 6 answer times 0.5”
Step 14 - Determine BMP volume:
Step 13 answer times appropriate value for the selected BMP*
Step 15 – Go to Step 1 for next outfall.
*Refer to DCR SWM Handbook for load removal worksheets.

12. Current BMP Selection Table 11-1 VDOT Drainage Manual
Water Quality BMP
Treatment Volume
Target Phosphorus Removal
Efficiency
Percent Impervious
Cover**
Vegetated filter strip
Grassed swale
10%
15%
16-21%
Constructed wetlands
Extended detention
Retention basin I
2xWQV
3xWQV
20%
35%
40%
22-37%
Bioretention basin
Bioretention filter
Extended detention-enhanced
Retention basin II
Infiltration
4xWQV
1xWQV
50%
38-66%
Sand filter
Retention basin III with
aquatic bench
65%
67-100%
*Innovative or alternate BMPs not included in this table may be allowed at the discretion of DCR and VDOT.
**Percent Impervious Cover: The ratio of the new impervious area and the area within the right-of-way and easements per project outfall.

13. Current IIM-195.7 Highlights
Entire lIM has been revised to add better clarity and organization to
content.
Definition section added to clarify meaning of various terms as they relate to VDOT activities.
"Site area" is defined for both linear and non-linear projects.
Provides guidance on the use permanent easements for determining site area.
Provides guidance on SWM requirements for work being performed on VDOT rights of way under a Land Use Permit.
Based on the requirements of State and local regulatory programs such as MS4, TMDL, Tributary Strategy, etc.
Guidance on SWM requirements for roadways being developed by other but which will come into the VDOT system for maintenance/operation (e.g., Subdivision Streets).
Provides guidance on exemption for milling and/or overlaying/reconstruction of existing impervious surfaces.
Area of existing pavement exempt.
Shoulder or ditch grading/filling not exempt.
Clarifies use of individual outfall analysis in determining application of VSMP Regulations requirements for linear projects

14. Current IIM-195.7 Highlights (cont.)
Provides separate sections defining criteria/requirements for:
Stream channel erosion
Flooding
Water quality requirements
Provides guidance for both linear and non-linear projects.
Provides guidance on both Performance Based and Technology Based
water quality criteria.
For Technical Based criteria for linear projects:
Post development percent impervious based on net increase in
Impervious area .
Same as IIM guidance .
Good until 1/11/2012.
Water Quality Volume for required BMPs based on total post development impervious area from within site draining to BMP .
Change from IIM requirement.

15. Current SWM Requirements
Projects, such as subdivision streets, industrial access roads, etc., which are designed and constructed by other parties and which are eligible for acceptance into the state roadway system for maintenance after completion of construction are not considered state agency projects and must, typically, conform to appropriate local regulations.
Prior to the issuance of a VDOT Land Use Permit or the acceptance of a roadway facility into the state roadway system, land disturbing activities which occur in a designated MS4 area or a watershed with an approved TMDL plan shall be reviewed by the appropriate VDOT personnel for compliance with the conditions of the MS4 General Permit and/or the approved TMDL plan and the requirements of the VDOT Implementation Plan for the MS4 General Permit conditions. Those activities found not to comply with the conditions of the MS4 General Permit or an approved TMDL plan or the VDOT MS4 Implementation Plan requirements and responsibilities shall not be issued a Land Use Permit nor be accepted into the state system of roadways until such compliance is demonstrated.

16. Current Directive on Low Impact Development (LID) Practices use within VDOT Maintained Right of Way
Currently, DCR has no published credits for LID practices in meeting water quality requirements. However, such practices are being requested as a means to improve water quality. If there is a proposal to use LID practices to meet water quality requirements, VDOT would need to get DCR concurrence on a project by project basis.
Language in the VDOT Subdivision Street Acceptance Policies is encouraging LID practices, even to the allowance of such inside VDOT right of way (with acceptable maintenance agreements with the locality). For those items inside the right of way, either our maintenance personnel would have to agree to the future maintenance requirements or we would have to execute agreements with the locality for them to maintain such facilities (assuming the facilities are constructed in conjunction with a subdivision development or County project).

17. Use of Manufactured Best Management Practices (BMP)
VDOT prefer to only use manufactured BMPs (and the oil grit separators are just one of many types) as a last resort. Use of such facilities requires review and approval by VDOT Central Office - Location and Design - Hydraulic Section.
Other conventional (and not so conventional) surface facilities are preferred where VDOT will have maintenance responsibility.

18. Stormwater Pollution Prevention Plan (SWPPP)
A Stormwater Pollution Prevention Plan (SWPPP) identifies potential sources of pollutants which may reasonably be expected to affect the stormwater discharges from the construction site and any off site support areas and describes and ensures implementation of practices which will be used to reduce pollutants in such discharges.

19. Stormwater Pollution Prevention Plan (SWPPP)
Required for all Land Disturbing Activities
Needing VSMP Construction Permit Coverage (VSMP Law and Regulations)
Needing ESC Plan (VDOT R&B Specification (e))
VDOT Guidance – IIM-LD-246 (latest version)

20. Things on the Horizon*
*Following Slides from Mr. Roy Mills earlier presentation.

21. New VSMP Regulations (DCR)
Items Impacting VDOT Projects
New water quality requirements
New BMP facilities
New water quantity requirements for channel erosion and flooding (replaces MS19)
Projects with allocated funds in Six Year Program grandfathered until 7/1/2019

22. Effluent Limitation Guidelines (EPA)
For Construction Site Run-off.
Implemented by EPA November 2009
Requires best available BMP’s for land disturbances less than 20 acres initially, then less than 10 acres.
Requires numeric turbidity limits (NTU) to be met for construction site runoff from land disturbances 20 acres or greater initially, then 10 acres or greater.
Requires monitoring to demonstrate compliance with numeric limits.

23. Effluent Limitation Guidelines (EPA) (Cont.)
Home Builders Association challenged EPA in court on numeric limit values.
EPA delayed implementation of numeric limitations until further study (18 months).
Effluent Limitation Guidelines (ELGs) will have to be included by DCR in VSMP General Construction Permit before they are required on land disturbance activities in Virginia. Current General Construction Permit expires on June 30, 2014.

24. TMDL Plans for Impaired Waters (DEQ)
Mandated by EPA as a result of court decree.
Implemented through the VSMP MS4 and Construction Permits
10 implementation plans approved for current VSMP MS4 and Construction Permit cycles.
Hundreds of additional implementation plans required to be addressed during next 5 year permit cycles.

25. TMDL Plans for Impaired Waters (DEQ) (Cont.)
Defines the pollutant of concern and develops a WLA for Permittee.
Typical pollutants are sediment, bacteria, nutrients, etc.
Flow TMDL now being used as a surrogate . Limitations placed on the amount of flow that can be released from site (e.g., 50% of one year 24 hour storm).

26. Chesapeake Bay Total Maximum Daily Load (TMDL)
Mandated by EPA by way of Presidential Executive Order
Pollutants of concern – phosphorus, nitrogen and sediment
Limitations placed on Agriculture, Urban Development, CSOs and Onsite Septic Systems
Impacts over 50% of the area of the State

27. Chesapeake Bay TMDL (Cont.)
Draft Va. Watershed Implementation Plan (WIP) submitted to EPA in September 2010
EPA approved TMDL on 12/29/10
Approved TMDL Includes Va. WIP (Phase I)
Virginia Phase II WIP currently under development (due for completion by end of this year)

28. Chesapeake Bay TMDL (Cont.)
Interim evaluation and course correction as needed in 2017
Target completion date of 2025 for full implementation of the CB TMDL program
Will potentially require BMP retrofits on roadways and facilities without any current BMPs and modifications to existing BMPs to achieve greater pollutant removal efficiency.

29. Impacts On VDOT Projects
MORE design time and cost
MORE right of way cost
MORE construction time and cost
MORE maintenance time and cost

30. QUESTIONS ?