SCOPE OF WORK (Last amendment 9/18/08) Update: Signed agreement in hand Work to proceed March 15, 2009 June 30, 2010

Transcription

1 SCOPE OF WORK (Last amendment 9/18/08) Update: Signed agreement in hand Work to proceed March 15, 2009 June 30, 2010 TITLE: IDENTIFICATION OF ILLICIT DISCHARGES TO STORM DRAIN SYSTEM PROBLEM/NEED: The Sakonnet River (Portsmouth Park) and The Cove (Island Park) are coastal waters located in the East Bay Section along the northeast coast line of Aquidneck Island in the town of Portsmouth, Rhode Island. The two waterbodies are classified as SA waters and are ranked within Group 1 (highest priority) of the state s 303(d) list of impaired waterbodies. The pollutant of concern is pathogens, as indicated by fecal coliform. This determination was a direct result of the RIDEM Shellfish Program s delineation of a permanent closure area encompassing approximately one hundred and eighty (180) acres (.28 sq. miles) of the Sakonnet River and one hundred and nine (109) acres (.17 sq. miles) of The Cove (See Appendix A). Although these two areas do currently meet the minimum ambient water quality standards of SA waters, they are unable to support the designated uses of those waters. Specifically the results of several shore line surveys, conducted by the RIDEM Shellfish Program, and the evidence of failing septic systems indicate that the threats of contamination exceed the standards set forth by the National Shellfish Sanitation Program. The potential for a public health risk associated with the consumption of contaminated shellfish resulted in the closures of these two areas. Although both areas are permanently closed to shellfishing, the RIDEM Shellfish Program s ambient water quality monitoring data show that fecal coliform concentrations at the sampling stations within the shellfish growing areas do not exceed Class SA standards for fecal coliform bacteria. However, the density of fecal coliform present in the Portsmouth Park stormdrain discharges exceeds standards set forth by both the RI Water Quality Regulations and the National Shellfish Sanitation Program. The potential public health risk associated with the possibility of direct discharge of human septage waste from failing septic systems into the shoreline area prompted the shellfishing ban. [1] The soils present within the Upper Sakonnet area are generally not suitable for the disposal of sanitary wastes; Portsmouth Park and Island Park are comprised of two distinctly different soil types. Portsmouth Park soils are poorly drained and contain a dense shale impervious layer close to the surface. This hillside community slopes from the west to the east toward the shoreline, which serves to convey groundwater from the upland area to the point of discharge along the shore. This uneven permeability can result in an extended wet surface soil condition after rain events and could explain Portsmouth Park s wet and constantly draining condition. The Soil Survey of RI considers the soil complex underlying Portsmouth Park as limited for onsite sewage disposal systems due to the slow permeability in the substratum. In contrast, soil in the Island Park Plat demonstrates a moderately rapid permeability in the surface layer and upper part of the subsoil, moderately rapid to rapid in the lower part of the subsoil and rapid in the substratum. The Soil Survey recommends that installation of onsite septic systems in this soil include careful design to prevent pollution of groundwater. Additionally, the shoreline of Island Park is a sand bar, which facilitates rapid water movement to the shore. In Island Park, the presence of old, inadequate or failing septic systems in the sandy soils likely contribute fecal coliform through groundwater flows directly into The Cove on the north side.

2 A study conducted by Save The Bay (STB) in 1983 indicated a high rate of failing septic systems in Portsmouth due to unsuitable soil conditions, small lot sizes, overloading due to inadequate design, improper construction and poor maintenance. The persistence of the high fecal coliform discharge in the Portsmouth Park storm drains, as well as the documentation of failing septic systems in Island Park, prompted RIDEM to conduct a two-year, EPA-funded study of the contamination problem from 1996 to The first step involved identifying failed septic systems and illegal cross connections between cesspools or septic systems and storm water systems in the study area of Island Park and Portsmouth Park. RIDEM Shellfish Program staff conducted a routine shoreline and follow-up survey of the Upper Sakonnet River on July 28, 29 and August 6, The study found pipes flowing during dry conditions in both Portsmouth and Island Park areas and sampling confirmed elevated fecal coliform bacteria. On November 5, 1987, RIDEM Shellfish Program conducted a follow-up visit to further investigate a portion of the Portsmouth Park storm water system This investigation identified illicit connections within the storm drain system and in-system sampling and observations indicated the presence of fecal coliform and indicators of sewage. A Shellfish Program report dated May 10, 1988 summarized further investigations of illegal tieins into the Aquidneck Road storm sewers. The area was revisited four times subsequent to the November 1987 visit and samples were taken representing the storm sewer, associated pipes, and the outfall into the Sakonnet River. Total and fecal coliform was found in flows from apparently unapproved tie-ins to the Aquidneck Avenue storm sewer system. This study was unsuccessful at locating a source of the high coliform counts; however the report does note discussions with area residents that indicate that the Portsmouth Park area is chronically wet. There have been a number of assessments and investigations done in the project area over the past twenty-four years including desktop assessments for planning efforts, assessment of soils and septic system failures and cesspool inventories, outfall reconnaissance, RIDEM Shellfish Shoreline Survey s, ambient water quality sampling, and limited in-system investigations that included manhole and catch-basin inspections, in-system sampling, and dye testing. These types of investigations are screening level investigations that were designed to identify potential illicit discharges to the storm drains and provide an indication of the types of potential pathways that exist. These previous investigations indicate that it is highly likely that there are wide-spread potential sources within the system and that there are multiple pathways that require further investigation. They are: Direct connections of sanitary discharges to the storm drain systems and of french drains that intercept groundwater contaminated by failing/inadequate septic systems or cesspools. Infiltration of groundwater contaminated by failing/inadequate septic systems or cesspools into the storm drain system. Overland discharges of storm water co-mingled with discharges associated with surface failures. Discharges related to direct connections of sanitary discharges may be low flow and intermittent. If the system is not flowing during dry weather, these discharges will not be seen until a wet weather event produces a discharge. If the system is discharging due to infiltrating groundwater, these discharges may be masked and diluted by clean groundwater. Discharges related to french

3 drains that intercept groundwater contaminated by failing septic systems or cesspools may not be evident during low groundwater periods when the outfalls are not flowing. Discharges due to overland discharges of storm water co-mingled with systems with surface failures may only be evident during wet weather events and may be diluted by clean storm water. In summary, the next step is to perform field investigations of the system and private property to confirm the sources. This program is designed to investigate and confirm sources primarily from the first two pathways described above, that is, either from direct connections to the storm drain system, or from infiltration of contaminated groundwater into the system via cracked or damaged pipes. Contaminated overland flows will most certainly be addressed if detected as part of the investigation, but these flows will not be the primary focus of the program. To be thorough, a program must be designed to investigate the system under both high and low groundwater conditions and must include appropriate methods of investigation for each condition. These may include in-system inspections and analytical sampling to isolate suspected sources, video inspections, smoke testing and dye testing, as well as private property inspections (See note 3). PROJECT AREA: The project area for the below described Scope of Work will be the watersheds and catchment areas contributing storm water runoff to (1) all Town-owned outfalls for all of the Portsmouth Park / Island Park TMDL area, (2) all Town-owned outfalls that showed high fecal counts during the Town s 2007 town-wide dry-weather outfall testing, (3) all outfalls that showed high dryweather fecal counts from any previous RIDEM shoreline surveys and (4) any State-owned outfalls along Park Avenue that are known or suspected to have interconnection with the Townowned system. This is will include 33 outfalls as shown in Appendix B. CATEGORIES OF NONPOINT SOURCE POLLUTION ADDRESSED: Storm water outfalls in the project area discharge directly into Narragansett Bay. A number of these outfalls have produced flows with high bacterial counts even during dry weather. Several studies have concluded that illicit discharges from failed ISDSs are the primary source of elevated bacterial loadings. During storm events, the pollutant loading increases due to higher inputs of sewage-contaminated groundwater and storm water. Inadequate ISDSs and illicit connections to the storm drain system (direct or indirect) are the primary source of pollutants. [2] PURPOSE: The purpose of the proposed project is to complete the essential first step in identifying and eliminating non-point source pollution discharges from the MS4 during dry weather. This involves correlating past sampling results and inspection observations by outfall and portion of the system, system and catchment mapping, outfall sampling, in-system sampling, catch-basin and manhole inspections, and follow-up tests, such as smoke and dye tests, to confirm the exact sources of pathogen discharges into the storm drain system. Past investigations have been limited and did isolate some suspected source areas and some individual suspect houses, but the investigations were not comprehensive over the project area and did not confirm the sources to the extent necessary. GENERAL PROJECT PLAN: This project involves performing tasks associated with (1) reducing nutrient and pathogen loading to the Town-owned storm drain system by establishing a public education program to

4 inform homeowners of good housekeeping practices, (2) identifying potential sources and confirming actual sources of dry weather fecal coliform contamination of the storm drain system, and (3) identifying and promoting remediation efforts to address these illicit connections and discharges. Tasks 1-4 below, are to be considered Phase I of this project and all work for these tasks will be performed by Town staff as in-kind services for the purposes of this contract. Phase I will also include any outfall testing (and lab services) previously done by Town staff as part of the Town s Phase II compliance efforts. Phase II, Tasks 5 & 6 are to be performed by a qualified consultant hired through the QBS selection process. Phase III, Task 7 will be completed by the Town. 1. Develop the legal authority to perform private property inspections: Adoption of a Storm Water Discharge Control Ordinance is necessary. 2. Educate the public: Develop and implement a public outreach program aimed at informing and educating citizens about the sources and consequences of pathogen and nutrient loading to the storm drain system and ways to eliminate or reduce those sources. Outreach efforts should include information on the impacts of poorly functioning septic systems, the negative consequences of illicit connections, and the importance of properly maintaining ISDSs. Local residents will be encouraged to follow a few simple good housekeeping practices such as: proper maintenance of septic systems, disposal of pet waste away from storm drains and the shoreline, minimized use of fertilizers and no feeding of waterfowl to discourage their prolonged residence in the area. Portsmouth will use public information meetings, advertisements, web site content, a targeted mailing of EPA-provided brochures, and possibly a steering committee to engage public involvement. All meetings will be held in compliance with local and state laws regarding public meetings. 3. Map system & identify potential pollution sources: This will include all field work necessary to create a GIS Map and database identifying the underground storm drain system and catchment areas for all of the Portsmouth Park / Island Park TMDL area storm drain outfalls, for any outfalls showing high dry-weather fecal counts from previous RIDEM shoreline surveys, for all outfalls that tested high fecal counts during the 2007 Town dry-weather storm water outfall testing, and for all State-owned Park Avenue outfalls that are known or suspected to interconnect with the Town system. These outfalls are identified in Appendix B. This mapping will include the location of all outfalls, storm drains, manholes, catch-basins, swales, ditches, conveyances and other surface features of the storm water system. The mapping will also include parcel data, onsite system status, topography, and estimated groundwater elevations and flow directions for the project area. The database will be designed to correlate all historical and new sampling and observations and will be maintained throughout the investigations. During field work to complete the mapping, manhole and catch basin inspections will be performed to map connectivity and to identify any direct connections or signs of dry weather flows or obvious signs of sewage contamination. If dry weather flows are found, they will be sampled and analyzed for sewage indicators (See note 1). Test results will be reported to RIDEM on agency provided forms. All necessary Lab fees for this Phase I work will be included in this contract. The investigation of the storm drain system and the mapping of watershed topography will continue upstream to a point where the entire watershed for each of the previously identified storm water outfalls is completed. 4. Develop an RFP and contract for consulting services to perform source identification and confirmation: Using the data developed by the Town in Phase I, Item #3 above as a starting point, the Town will work with RIDEM to develop a Scope of

5 Work and RFP to hire a consultant to undertake field investigations necessary to identify and confirm all specific sources of illicit discharge to the storm water system contributing to the outfalls listed above. Revision of the original Scope of Work and the grant agreement between the Town and RIDEM may be necessary at this point in the project, depending upon the results of the Phase I mapping of potential sources efforts. Field investigations may include smoke testing performed during low groundwater periods, video inspections during high groundwater periods (see note 2), in-system isolation and sand-bagging to facilitate further sampling to isolate potential sources. In order to confirm pollution sources, this effort may also include performing on-site private property investigations consisting of homeowner surveys, Surface Condition Analysis, and dye testing. 5. Identification of potential pollution sources: This Phase II effort, to be performed by a qualified consultant, will execute the contract described above in item #4. 6. Summary Report: This report, to be produced by the consultant, will (1) summarize the findings of the investigations and identify all confirmed sources of pollution to the outfalls in the project area, (2) evaluate if the project area has been adequately and comprehensively investigated or if the findings indicate additional system and private property inspections are necessary, (3) make recommendations, including cost estimates to the private property owner, for remediation efforts to address all confirmed illicit connections and discharges found during the investigation, and (4) make recommendations for a confirmatory outfall and system sampling effort to be implemented after remediation is completed to confirm that all illicit connections and discharges have been eliminated. The consultant will be required to present the Summary Report in a public hearing to the Portsmouth Town Council. 7. Prepare and implement a Remediation Plan: Using the authority of the Storm Water Discharge Control Ordinance, the Town will seek to eliminate any and all illegal discharges to the Town-owned storm drain system identified and confirmed by this investigation. This final step in the process will include notification to individual property owners, monitoring of abatement activities, and post-abatement testing to confirm the elimination of the pollution source. [1] First three paragraphs were excerpted from pages 4-5 of Preliminary Data Report for Sakonnet River / The Cove TMDL for Fecal Coliform, prepared by Office of Water Resources, RIDEM, dated January [2] Excerpt from Executive Summary of Draft Wastewater Facilities Plan, by Louis Berger Group, dated October 2002.