AGENDA REQUEST

Sponsor: 

 Board of Supervisors Meeting Date:

William G. Downey, Scott District Supervisor

 

December 13, 2007

Staff Lead:

Department: 

Kimberley Fogle, Assistant Director

 

Community Development

 

Topic:

 

An Ordinance to Amend Subsection 3 of Section 204.2 of the Design Standards Manual to Limit Its Application to Point Source Stormwater Runoff

 

Topic Description: 

Section 204.2 of the Design Standards Manual (DSM) provides a general policy for water quality in stormwater management (SWM) and Best Management Practices (BMP) facilities.  Subsection 3 requires the adequate treatment of stormwater runoff generated from new development sites prior to discharge into a jurisdictional wetland or local water body.  This proposed amendment specifies that the provision is intended to apply to point source discharges of stormwater and not from non-point source runoff, such as dispersed sheet flow from residential lawns.

 

Requested Action of the Board of Supervisors:

Consider one of the following options:

  1. Adopt the ordinance as originally drafted to specify that Subsection 3 applies to point source discharges of stormwater.  Delete the amendment regarding tree conservation easements that was added at the November 8, 2007 meeting;
  2. Delete Subsection 3 of Section 204.2 of the DSM in its entirety; or
  3. Retain the existing language of Subsection 3 to apply to both point and non-point discharges of stormwater and add language to clarify that natural vegetative areas within tree conservation easements with a maximum slope of 5% are considered a method of adequate treatment for the sheet flow of stormwater.

 

Financial Impact Analysis: 

There is no financial impact.

 

Summary Staff Report:

Subsection 3 of Section 204.2 provides that all stormwater generated by new development shall not be discharged into a jurisdictional wetland or local water body without adequate treatment.  The standard for adequate treatment has been the use of a vegetative filter strip of about 25 feet in width to filter out pollutants and particulate matter prior to the water entering the wetland or water body.  A similar provision was part of the draft Virginia Stormwater Management Model Ordinance at the time the County adopted its Stormwater Management Ordinance (and this provision) in 2002.  The Stormwater Management Ordinance was subsequently incorporated into an overall Design Standards Manual.  The State eliminated this provision from the Virginia Stormwater Management Law when it was adopted in 2005.  The Army Corps of Engineers and the Department of Environmental Quality (DEQ) have oversight related to impacts to wetlands and water bodies.   The DEQ Virginia Water Protection individual permits’ Standard Project Conditions have a clause in them that requires pretreatment of surface water runoff prior to entering into regulated wetland areas.  (A DEQ staff member has indicated that they have contemplated removing this language from their standard permit conditions because they feel “this sort of stormwater management is a local issue that should be handled by localities.” (email from Allison C. Dunaway, Virginia Water Permit and Regulatory Team Leader, DEQ, June 6, 2007))

Since adoption of this provision in 2002, it has been interpreted as including both point source and non-point source discharges into wetlands.  The non-point sources are primarily lawns and yards associated with residential development.  This has shown to be problematic for residential projects, such as Brookside, where there are a considerable amount of wetlands and they have already paid for or mitigated their impacts to the wetlands in accordance with their Corps of Engineers permit.  In the application of this provision,  the County has encouraged and stressed the importance of preserving existing vegetation as filter strips for non-point source treatment as long as the topography is relatively flat (less than 5% slope) to maintain sheet flow conditions as opposed to disturbing the land and increasing the potential of sediment eroding into the wetlands.

This amendment proposes to specify the requirement for adequate treatment for point source discharges.  Having pretreatment of stormwater runoff prior to being discharged into jurisdictional wetlands is a good practice because it helps to preserve the overall health of the ecosystem as well as the vibrancy of the wetlands.  To overload them with concentrated pollutants suspended in stormwater runoff that will primarily be collected from roadway areas and/or other impervious areas would contribute to the wetlands premature degradation and possible destruction.  In addition, pretreatment will allow for screening out trash, debris, and other large material, as well as for initial filtering of other smaller suspended particulate matter in the runoff that over time will eventually choke the wetlands ability to thrive.

The addition of the point source language in our Design Standards Manual reinforces the importance of pretreatment in the preservation and protection of these wetland areas.

Updated Information:

The Board of Supervisors held a public hearing on this amendment to the Design Standards Manual at their November 8, 2007 meeting.  At that time, a change was made to the draft ordinance to specifically clarify that a tree conservation easement is considered a method of adequate treatment for the discharge of stormwater into a wetland.  In follow-up discussion with Engineering, it was found that the maintenance of natural vegetation in tree conservation easements works well as a filter for the sheet flow of stormwater (non-point source) but does not work for point source discharges unless that discharge is reduced to sheet flow (with a level spreader or similar mechanism) prior to its discharge.  It is recommended that the change made at the November 8 meeting be deleted if the provision is adopted to apply only to point source discharge.

 There was considerable discussion about whether the overall provision for pretreatment  was in concert with the Virginia Stormwater Management Law and what other laws regulate the pretreatment of stormwater prior to discharge into jurisdictional waters.  Staff has conducted some research into this issue and offers the following information to assist the Board’s in its deliberation of this proposed amendment.

Current County Practice:  In the review of development projects, the County’s practice has been to interpret Subsection 3 of Section 204.2 to apply to the discharge of all stormwater, both piped and sheet flow from adjoining property, whether the adjoining land is developed as a parking lot or as residential yard areas, into jurisdictional wetlands or water bodies.  It has been applied in all instances within a development site as well as with water leaving a development site.  (Applying the requirements within a development site has been raised by some as more restrictive than the State requirements.   4VAC50-60-50.H. reads in part, “Proposed residential, commercial or industrial subdivisions shall apply these stormwater management criteria to the land disturbance as a whole.  Individual lots in new subdivisions shall not be considered separate land-disturbing activities, but rather the entire subdivision shall be considered a single land development project.”)

In 1982, the County endorsed the goals of the Occoquan Basin Non-Point (meaning stormwater) Pollution Management Program to maintain “acceptable levels of water quality within the Occoquan Basin’s free-flowing streams and impoundments” through the application of stormwater quality BMPs.  Over time, the Board has encouraged stormwater management, recognizing the community’s sensitivity to Fauquier County’s location at the headwaters of both the Rappahannock and the Occoquan.  With the adoption of the stormwater management ordinance in 2002 (and the DSM in 2005), the Northern Virginia BMP Handbook was designated as the authority for the design and review of BMP facilities using the Occoquan Method.   The Occoquan Method is performance-based and offers more flexibility than that required under strict compliance with State SWM requirementsThe State approved our use of the Occoquan Method in their review of our SWM ordinance prior to its adoption.  The basic principle is that SWM/BMPs are required for at least 80% of a development site (with up to 20% of the stormwater allowed to bypass and not be treated).  A minimum of 40% of the calculated phosphorus for the entire site must be removed through the use of sediment forebays, bioretention facilities, filter strips and other BMP measures.  (A credit is given for floodplain and wetland areas.)  A project must meet this removal rate at the point of discharge from the project site.  In some cases, water from the wetlands will flow into the SWM facility, thus the adequate treatment prior to discharge into the wetland may actually be a pretreatment.  In other instances, generally with the sheet flow from yard areas, this water is not captured in the SWM/BMP facility and is part of the 20% bypass water.  Thus, the use of pretreatment for this bypass water prior to entering the wetland may actually result in a somewhat higher level of phosphorus removal than the minimum 40% required.  It is also a means to help ensure the health of the wetland and to improve water quality within the site, not just as the water leaves the site.

Federal Requirements:  Section 404 of the Clean Water Act (CWA), as amended, established a permit program that deals with the placement of dredged or fill materials into wetlands and other "waters of the United States."   The 404 permit program is administered jointly by EPA and the U.S. Army Corps of Engineers.  

The Corps handles the actual issuance of permits (both individual and general); it also determines whether a particular plot of land is a wetland or water of the United States. The Corps has primary responsibility for ensuring compliance with permit conditions, although EPA also plays a role in compliance and enforcement. 

Among the many issues reviewed and analysis needed as part of the issuance of any wetlands disturbance permit is the evaluation of the suspended particulates/turbidity for the possible loss of environmental characteristics and values that can result from greatly elevated levels of suspended particulates in the water.

In addition, Section 401 of the CWA requires that before a federal agency can issue a license or permit for construction or other activity, it must have received from the state in which the activity will take place a written certification that the activity will not cause or contribute to a violation of relevant state water quality standards (see VSMP below). 

The CWA makes it illegal to discharge pollutants from a point source (and discharges from construction sites disturbing over one acre are considered in this classification) to the waters of the United States. Section 402 of the Act creates the National Pollutant Discharge Elimination System (NPDES) regulatory program. Point sources must obtain a discharge permit from the proper authority (in our case, the Virginia Department of Conservation and Recreation).  

Though the CWA does contain a long-range goal of zero discharge of pollutants, these permits do not, as the name of this program might suggest, simply say "no discharge." Rather, they set limits on the amount of various pollutants that a source can discharge in a given time.

Where wetland impacts occur, the Department of Community Development asks for proof of wetlands disturbance permits from the Corps of Engineers and the Department of Environmental Quality (DEQ) and typically requests copies of the permits issued.  One of the Standard Project Conditions of the DEQ Individual Permit states:  “Untreated stormwater runoff shall be prohibited from directly discharging into any surface waters.  In accordance with the Virginia Erosion and Sediment Control Handbook, Third Edition, 1992, appropriate best management practices (BMP) shall be deemed suitable treatment prior to discharge into surface waters.”    

State Permitting:  For compliance with the CWA, the Commonwealth requires a Virginia Stormwater Management Plan permit (VSMP) for development sites greater than one acre in size.  This permit is administered through the Department of Conservation and Recreation (DCR).  The County requires evidence of application for this permit prior to the issuance of a land disturbing permit for every project requiring a VSMP permit.  This is a general permit, which by execution of the application (Notice of Intent to Comply) the developer agrees to comply with a series of general conditions, including the preparation of a Stormwater Pollution Prevention Plan (SWPPP) in accordance with defined standards.  The SWPPP is not a reviewed plan, but one to which DCR may require modifications to comply with the VSMP permit during construction of the project.  DCR spot checks construction sites and may shut down a project for failure to have a copy of the SWPPP available or to follow the SWPPP on site.  Most of the provisions of the SWPPP deal with the construction activity; however, there are specific criteria required in the preparation of the SWPPP that address the control of pollutants in stormwater discharges after construction operations have been completed, including the technical basis used to select the practices to control pollution and flows that exceed predevelopment conditions.

Practice of Other Jurisdictions:   Staff has surveyed several other jurisdictions in the area (Stafford, Albemarle, Spotsylvania and Loudoun counties) about their requirements and practices for pretreatment within the site prior to the main SWM/BMP facility (and discharge from the site). 

Albemarle:   Albemarle County’s requirements are actually more stringent than the State guidelines.  The Albemarle County Code  states, “If the development is located within a development area or an area of infill and redevelopment, stream buffers shall be retained if present and established where they do not exist on any lands subject to this article containing perennial streams, and/or nontidal wetlands contiguous to these streams. The stream buffer shall be no less than one hundred (100) feet wide on each side of such perennial streams and contiguous nontidal wetlands, measured horizontally from the edge of the nontidal wetlands, or the top of the stream bank if no wetlands exist.” (Section 17-317 (A))  In essence, they require a 100-foot vegetative buffer along jurisdictional wetlands and water bodies.

Loudoun:  Loudoun County has a less restrictive provision within their Facilities Standards Manual, which states:  “Discharge of stormwater pollutants to wetlands shall be minimized, except where constructed wetlands are used as a BMP and are designed in accordance with County Standards.” (Section 5.310 F)   In practice, Loudoun County is more laissez-faire and applies this provision to the point discharge of stormwater into wetlands, with the focus more on reducing potential erosion before entering the wetland not on improving water quality.  They have indicated that they have not been consistent in its application.   

Spotsylvania and Stafford:  Both Spotsylvania and Stafford counties have the same practice with regard to discharges into wetlands and are being discussed together.  Neither county enacted the language from DCR’s Model Ordinance but both utilize the performance criteria of the Chesapeake Bay Preservation Area Designation and Management Regulations, which requires treating stormwater runoff prior to discharging into wetlands located offsite.  It does not, however, ensure treatment of all stormwater runoff prior to discharging into wetlands located within the project site. 

In recent years, both counties (along with the City of Fredericksburg) have developed a policy document with strategies to improve existing subdivision and regulations to benefit both the natural environment and the community.  One of the principles (#22) of the document states, “New stormwater outfalls should not discharge untreated or unmanaged stormwater into jurisdictional wetlands, sole-source aquifers, or other water bodies.” 

Stafford and Spotsylvania counties are currently working on revisions to their stormwater management regulations as a result of EPA push on the State for more stringent regulations to improve the water quality of the Chesapeake Bay knowing it will eventually become the responsibility of the local level.  In their new regulations, they expect to be applying principle #22 above to point source discharges only, but applying it for all discharge into wetlands, both within the site and as water leaves the site.

Additionally, DCR is currently exploring new regulations to increase the required removal rates for phosphorus, nitrogen and suspended solids in stormwater to help improve water quality in the Chesapeake Bay.   The most recent evaluation of the health of the Chesapeake Bay was released this week and, according to an article in the Washington Post, the bay’s pollution has actually taken a turn for the worst.  The recent study, conducted by the U.S. Geological Survey, shows increases in the amount of phosphorus and nitrogen, which help fuel the large algae blooms that create dead zones in the bay.   

 

Back to Agenda...