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Watkins Creek ARAP_2019_June WATKINS CREEK BACTERIA TMDL ASSUMPTIONS AND REQUIREMENT ATTAINMENT PLAN June, 2019 Prepared by Metropolitan St. Louis Sewer District in coordination with its MS4 co-permittees. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP TABLE OF CONTENTS 1.0 Introduction and Purpose ....................................................................................................................... 3 1.1 Watkins Creek Bacteria TMDL ....................................................................................................... 3 1.2 MS4 Permit Requirements ............................................................................................................... 5 2.0 E. coli Bacteria and its Potential Sources ........................................................................................ 6 2.1 Sanitary Sewer Infrastructure .......................................................................................................... 6 2.2 Individual Sewage Disposal Systems .............................................................................................. 8 2.3 Urban Stormwater Runoff ................................................................................................................ 8 2.4 Riparian Conditions ......................................................................................................................... 9 2.5 Illicit Straight Pipe Discharges ........................................................................................................ 9 3.0 TMDL Implementation Activities ......................................................................................................... 9 3.1 St. Louis County Phase II Stormwater Management Plan ............................................................... 9 3.1.1 MCM #1, Public Education and Outreach of Stormwater Impacts .................................. 10 3.1.2 MCM #2, Public Involvement and Participation .............................................................. 11 3.1.3 MCM #3, Illicit Discharge Detection and Elimination ..................................................... 12 3.1.4 MCM #4, Construction Site Stormwater Runoff Control ................................................. 13 3.1.5 MCM #5, Post-Construction Stormwater Management in New Development and Redevelopment ............................................................................ 14 3.1.6 MCM #6, Pollution Prevention Good Housekeeping for Municipal Operations .............. 15 3.2 Project Clear .................................................................................................................................. 15 3.2.1 Sanitary Sewer Overflow Control Master Plan ..................................................................... 16 3.2.1.1 Sewer System Evaluation Survey (SSES) ................................................................... 16 3.2.1.2 Master Plan Projects .................................................................................................... 17 3.2.2 Capacity, Management, Operations, and Maintenance Program .......................................... 18 3.2.3 Fats, Oil, and Grease Program .............................................................................................. 19 3.3 TMDL Best Management Practices Targeting Bacteria ................................................................ 19 4.0 Evaluation ............................................................................................................................................ 22 LIST OF FIGURES Figure 1. Watkins Creek showing the impaired reach for the bacteria TMDL, and watershed location in St. Louis County, Missouri.. ............................................................... 4 LIST OF TABLES Table 1. TMDL requirements for E. coli bacteria at specific flows in Watkins Creek. ............................... 5 Table 2. Summary of Sanitary Sewer Gravity Pipes by Pipe Diameter and Material in Watkins Creek Watershed as of February 22, 2019 ..................................................................................... 7 Table 3. Summary of Sanitary Sewer Pipes by Pipe Diameter and Material that have Received Cured in Place Lining in Watkins Creek Watershed as of February 22, 2019 ............... 7 Table 4. Summary of Capacity and Non-Capacity Overflows and Bypasses for Watkins Creek Watershed, 01/01/2016 - 12/31/2018 .............................................. 8 Table 5. TMDL Best Management Practices Targeting Bacteria in the Watkins Creek Watershed ............................................................................................................ 21 APPENDICES Appendix A. SSO Control Master Plan Projects in the Watkins Creek Watershed Appendix B. Bacteria and Nutrient Best Management Practices Strategy Review MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 3 1.0 Introduction and Purpose Watkins Creek first appeared on Missouri’s Section 303d list of impaired waters for elevated concentrations of Escherichia coli (E. coli) bacteria in 2006. In-stream concentrations of E. coli have been found to exceed Missouri’s water quality criterion for its designated use of Whole Body Contact Recreation Category B, which is set at 206 E. coli counts per 100 milliliters of water (206 counts/100mL). According to Missouri’s 303d listing methodology, a water designated for Whole Body Contact Recreation Category B use is determined to be impaired by bacteria if the geometric mean in a given recreational season exceeds 206 counts/100mL in any of the last three years with available data. At least five samples are needed from a single recreational season, which is defined as the period from April 1 through October 31. Watkins Creek remained on Missouri’s Section 303d list of impaired waters for E. coli from 2006 to 2016. On July 13, 2016, the United States Environmental Protection Agency (USEPA) approved Missouri’s bacteria Total Maximum Daily Load (TMDL) for Watkins Creek1. As required by the Federal Clean Water Pollution Control Act, the Missouri Department of Natural Resources (MDNR) issues the Metropolitan St. Louis Sewer District (MSD), St. Louis County, and 59 St. Louis County municipalities a general operating permit to discharge authorized stormwater from the Municipal Separate Storm Sewer System (MS4) servicing the Plan Area to waters of the state. The most recent permit (General Operating Permit MOR040005) was issued on December 14, 2016 and requires regulated MS4s identified in a TMDL with an applicable Wasteload Allocation (WLA) to implement steps toward the attainment of the applicable WLA in accordance with 40 CFR 122.44(k)(2) and (3). In this case, MSD and its co-permittees are required to develop an Assumptions and Requirement Attainment Plan (ARAP) to address applicable assumptions and requirements in the Watkins Creek bacteria TMDL. The purpose of this document is to fulfill requirements in the MS4 permit issued to MSD and its co- permittees, specifically Section 3.1. MS4s Subject to Total Maximum Daily Loads (TMDL). This TMDL ARAP will address the aggregated wasteload allocation assigned to the MS4 area in the Watkins Creek bacteria TMDL. Procedures and activities to be implemented in accordance with the MS4 permit are provided herein. Most importantly, this TMDL ARAP includes a description of implementation activities and best management practices (BMPs) that will be used to target known sources of bacteria specific to the Watkins Creek watershed, as well as a prioritized schedule for their implementation. BMP effectiveness will be evaluated after implementation, and those found to be ineffective will be revised or replaced accordingly. Both the Watkins Creek bacteria TMDL and TMDL Implementation Plan2 were used in the development of this TMDL ARAP. 1.1 Watkins Creek Bacteria TMDL Watkins Creek is located in north St. Louis County. Its most upstream extent occurs along Parker Road, west of Lewis and Clark Boulevard near Black Jack and it generally flows to the southeast for approximately 6.7 miles before it reaches its confluence with the Mississippi River. The watershed covers approximately 6.5 square miles and contains karst geologic features, including one tributary stream classified as gaining. The most downstream 1.4 miles of Watkins Creek (WBID 1708) is Class C water which has been assigned the following designated uses: Livestock and Wildlife Protection; Irrigation; Protection and Propagation of Fish, Shellfish, and Wildlife – Warm Water Habitat; Human Health Protection; Secondary Contact Recreation; and, Whole Body Contact Recreation Category B. It is this lowermost portion of Watkins Creek which has been listed as impaired for bacteria. Watkins Creek is 1 Missouri Department of Natural Resources Water Protection Program. 2016. Bacteria total maximum daily load (TMDL) for Watkins Creek, St. Louis County and St. Louis City, Missouri. Completed: Dec. 31, 2014. Approved: July 13, 2016. 38pp. 2 Missouri Department of Natural Resources Water Protection Program. 2014. Bacteria total maximum daily load implementation plan for Watkins Creek Water Body ID No. 1708, St. Louis County. 31pp. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 4 considered an urban stream and its watershed includes portions of the following MSD co-permittees: Black Jack, Bellefontaine Neighbors, and St. Louis County (unincorporated areas). Figure 1. Watkins Creek showing the impaired reach for the bacteria TMDL, and watershed location in St. Louis County, Missouri. A TMDL is a calculation that sets the amount of pollutant a water body can assimilate without exceeding the water quality criterion for that particular pollutant. The TMDL allocates the pollutant load among three components: 1) Wasteload allocation (WLA) for all point sources and MS4 Operators; 2) Load allocation (LA) for all nonpoint sources and natural background sources; and, 3) Margin of Safety (MOS) to account for any uncertainty in data or model assumptions. The TMDL is equal to the sum of the wasteload allocation, load allocation, and margin of safety as expressed in the following equation: TMDL = ΣWLA + ΣLA + MOS The Watkins Creek bacteria TMDL was developed using a numeric target concentration of 206 counts/100mL and a load duration curve. The target concentration represents Missouri’s water quality criterion of 206 E. coli counts per 100mL of water. The load duration curve applied average daily discharge data (cfs) between May 9, 1997 to April 4, 2011 from the United States Geological Survey MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 5 (USGS) gage station USGS 07001985 located at Fry Lane in Unincorporated St. Louis County east of the City of Bellefontaine Neighbors. Discharge data were corrected to account for a larger drainage area as delineated by the outlet of the impaired reach of Watkins Creek. The numeric target concentration was multiplied by the corrected average daily discharge and a conversion factor to calculate the daily load (counts/day) at specific discharges. Regulation of stormwater discharges from systems owned or operated by MS4s in Watkins Creek watershed is covered under two MS4 permits. The first MS4 permit is held by MSD and its 60 co- permittees (referred to as MSD MS4 permit from hereon) and covers a jurisdiction of approximately 94.6 percent of the watershed2. The second MS4 permit is held by the Missouri Department of Transportation (Permit No. MO-R0400563) and covers the remaining 5.4 percent2. There are no other permitted facilities in Watkins Creek watershed that might reasonably contribute to bacteria loading, thus all of the WLA was assigned to the MS4 area. Furthermore, since it was not possible to accurately disaggregate E. coli loading for each MS4, the WLA was assigned as an aggregate wasteload to the total MS4 area. Please see Table 1, adapted from the bacteria TMDL for Watkins Creek1. Table 1. TMDL requirements for E. coli bacteria at specific flows in Watkins Creek1. Percentile Flow Exceedance Flow (cfs) TMDL (counts/day) MS4 WLA (counts/day) LA (counts/day) 95 0.16 8.22E+08 8.22E+08 0 75 0.59 2.97E+09 2.97E+09 0 50 1.38 6.95E+09 6.95E+09 0 25 3.64 1.83E+10 1.83E+10 0 10 13.80 6.95E+10 6.95E+10 0 cfs =cubic feet per second; WLA = wasteload allocation; LA = load allocation While on-site wastewater treatment systems are noted in the TMDL as a potential nonpoint source, they are not expected to contribute to the bacteria impairment if properly functioning and were assigned a load allocation of zero. In addition, the catchments that contribute stormwater runoff to the outfalls permitted under the MSD MS4 permit were not identified during development of the TMDL. Therefore, the nonpoint source load allocation (LA) was not disaggregated from the MS4 WLA and no load allocations were assigned in the Watkins Creek bacteria TMDL. The margin of safety component is considered implicit because of conservative assumptions used in the TMDL model, the use of multiple years of stream discharge data collected under a complete range of conditions, reduced uncertainty of the sources of the bacteria impairment, and remediation of bacteria sources through MSD’s Project Clear program. In addition, the daily load estimated value used the recreation-season geometric mean while at the same time omitting bacteria decay rates, which are overlapping conservative assumptions. 1.2 MS4 Permit Requirements Missouri General Operating Permit MOR040005, Section 3.1.1, requires any regulated MS4 identified in a USEPA approved or established TMDL with an applicable WLA to implement steps towards the attainment of applicable WLA in accordance with 40 CFR 122.44(k)(2) and (3). Section 3.1.2 of the permit states the permittee shall develop a TMDL ARAP to address the TMDL’s assumptions and requirements where applicable. The TMDL ARAP shall be incorporated into the Stormwater Management Plan (SWMP) and include, at a minimum, the following: 3.1.2.1 A process to identify potential sources of the pollutant(s), BMPs to be implemented to address the sources within their MS4, a prioritization of those actions, and a schedule including beginning MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 6 and ending milestones by month and year. The schedule for the implementation of the TMDL ARAP shall be completed as soon as practicable, but is not limited to the term of this operating permit (i.e. 5 years) as attainment can take years or even multiple permit terms. 3.1.2.2 BMPs developed or designed with a purpose of reducing the pollutant(s) of concern. Each BMP shall contain a description of the BMP, the purpose of the BMP, and the expected result of the BMP. 3.1.2.3 Measurable goals shall be established for each BMP or in conjunction with multiple BMPs. Each measurable goal shall contain a statement clearly indicating how it will be established to determine the appropriateness of identified BMPs and progress toward the expected results of the BMP. Measurable goals shall be quantifiable; however, if it is not feasible to utilize a measurable goal that is quantifiable, then the permittee shall provide justification indicating why the measurable goal cannot be quantifiable. If applicable, measurable goals shall also utilize interim and completion milestone dates, and a periodic frequency of measurement to document progress. It is recommended that interim and final milestone dates are established with a format of month and year. If the format of month and year cannot be utilized, the permittee shall ensure that schedules have the minimum of 1st, 2nd, 3rd, 4th, and 5th year of the operating permit. 3.1.2.4 An iterative process to be utilized by the permittee that documents how each BMP is evaluated and subject to replacement or modification. The permittee shall apply reasonable further progress by replacing or modifying ineffective BMPs with effective BMPs. 2.0 E. coli Bacteria and its Potential Sources E. coli bacteria commonly inhabit the intestines of warm-blooded animals and their feces. In-stream contributions of E. coli usually originate from humans, pets, livestock, and wildlife. There are a variety of pathways E. coli might enter a waterway, such as stormwater runoff from agriculture and urban lands, failing septic systems and illicit connections, and discharges from sewage infrastructure related to wastewater treatment. The presence of E. coli measured at high concentrations indicates contamination by fecal matter. While the broad group of E.coli bacteria are mostly considered harmless, its presence is used an indicator of other pathogenic bacteria, viruses, and other microorganisms. Diseases from those pathogens can cause eye, ear, nose, throat, and respiratory infections, as well as gastrointestinal illness. Missouri’s Section 303d lists of impaired waters from 2006-2016 note the source of E. coli bacteria in Watkins Creek as urban runoff, urban nonpoint source pollution, or urban runoff/storm sewers. The Watkins Creek bacteria TMDL describes several specific sources of E. coli bacteria including the sanitary sewer system, onsite wastewater treatment systems (referred to herein as individual sewage disposal systems), urban stormwater runoff, riparian corridor conditions, and to a lesser extent, straight pipe illicit discharges. In particular, human sources of pathogens (e.g., sanitary sewer discharges and onsite systems) are considered a higher human health risk depending upon the duration and type of exposure. The following information is a summary of all potential sources of bacteria to Watkins Creek. 2.1 Sanitary Sewer Infrastructure There are no permitted facilities that discharge domestic or municipal wastewater treatment systems in the Watkins Creek watershed. MSD’s Bissel Point Treatment Plant which receives wastewater generated in the Watkins Creek watershed is located about 5.5 miles south of the watershed. Sanitary sewer infrastructure is present throughout the watershed however, comprising nearly 73.7miles of pipe. A summary of public gravity fed sanitary sewer pipes found in the watershed is provided in Table 2, and a summary of sewer pipes that have received cured-in-place lining rehabilitation is presented in Table 3. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 7 Table 2. Summary of Sanitary Sewer Gravity Pipes by Pipe Diameter and Material in Watkins Creek Watershed as of February 22, 2019. Pipe Diameter (inches) VCP Plastic RCP Cast Iron or DIP CP CMP Other Sub-Total Length in Feet 6 627 329 -- -- -- -- -- 956 8 232,716 78,950 490 275 -- -- 351 312,782 10 14,143 6,209 -- 112 576 -- -- 21,040 12 3,708 5,240 -- 865 -- 14 -- 9,827 15 4,787 2,729 -- 81 -- 33 -- 7,630 18 1,783 604 -- -- -- -- -- 2,387 21 555 220 1,813 -- -- -- -- 2,588 24 53 -- -- -- -- -- -- 53 27 768 -- 2,365 -- -- -- -- 3,133 30 38 286 9,447 -- -- -- -- 9,771 33 -- -- 9,531 -- -- -- -- 9,531 42 -- -- 478 -- -- -- -- 478 48 -- -- 87 -- -- -- -- 87 Total 259,178 94,567 24,211 1,333 576 714 47 380,263 VCP is vitrified clay pipe; RCP is reinforced concrete pipe; DIP is ductile iron pipe; CP is concrete pipe; and CMP is corrugated metal pipe. Table 3. Summary of Sanitary Sewer Pipes by Pipe Diameter and Material that have Received Cured-in-Place Lining in Watkins Creek Watershed as of February 22, 2019. Pipe Diameter (inches) VCP PVC RCP CP Sub-Total Length in Feet 8 48,262 158 -- -- 48,420 10 4,422 108 -- 792 5,322 12 5,156 -- -- -- 5,156 15 2229 -- -- -- 2,229 18 604 -- -- -- 604 21 -- -- 220 -- 220 30 -- -- 286 -- 286 Total 60,673 266 506 792 62,237 VCP is vitrified clay pipe; RCP is reinforced concrete pipe; DIP is ductile iron pipe; CP is concrete pipe. In addition to sewer pipes, there are 1,785 sanitary manholes in the Watkins Creek watershed that fall under public and private ownership. Of those, 1,698 fall under MSD ownership. Manholes are mostly constructed of poured-in-place concrete, brick, precast sections of concrete, and other materials. MSD owns and operates 1 sanitary pump station within the watershed. Force mains in Watkins Creek watershed total nearly 1.7 miles. There were four constructed sanitary sewer overflow (SSO) points first described in the TMDL. One additional constructed SSO has since been described. These five constructed SSOs are scheduled to be eliminated over the period of 2019-2023 per MSD’s Project Clear program. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 8 Unintended overflows from the sanitary system however may still occur from time to time as a result of blockages, line breaks, power failures and vandalism. A summary of capacity and non-capacity overflows and bypasses in the Watkins Creek watershed for the period of January 1, 2016 through December 31, 2018 is provided in Table 4. Table 4. Summary of Capacity and Non-Capacity Overflows and Bypasses for Watkins Creek Watershed, 01/01/2016 - 12/31/2018. Cause Count Remedy Widespread Flooding 1 Floodwaters Receded Equipment Failure 2 Repaired Total 3 -- As part of the SSO Master Plan requirement in MSD’s federal consent decree3, MSD conducted a Sewer System Evaluation Survey (SSES) for the Watkins Creek watershed. SSES findings related to sewer defects and SSO Master Plan remedial projects are described in Section 3.2.1.1 of this ARAP and Appendix A, respectively. 2.2 Individual Sewage Disposal Systems Individual sewage disposal systems are considered nonpoint sources of pollution. Failing systems are known sources of bacteria that can enter nearby streams through surface and subsurface flows. The Watkins Creek bacteria TMDL referenced two sources of information focusing on failure rates of individual sewage disposal systems. The first, EPA’s Spreadsheet Tool for Estimating Pollutant Load (STEPL), estimates the failure rate in St. Louis County as being 39 percent based upon census data from the 1990s. The second, a study conducted by the Electric Power Research Institute suggests that up to 50 percent of the systems in Missouri may be failing. In a more recent survey conducted specifically for MSD to gather information on environmental awareness in MSD’s service area, out of 570 residents contacted by either mail or online, 4% (22) indicated they had a septic system at their home4. When residents were asked if their septic system had been serviced in the last five years, 64% (14) of those indicated it had, 14% (3) said it had not, and 23% (5) were unsure. Of 18 residents asked about the age of their system, 28% (5) said their septic system was more than 30 years old. As referenced in the Watkins Creek bacteria TMDL, there are approximately 573 parcels in the watershed suspected of not having a connection to the public sewer. Non-sewered parcels include those with structures and those without, though it is not directly known how many parcels with existing structures have an individual sewage disposal system in operation. Therefore, contributions of bacteria from failing individual sewage disposal systems are likely, however the scope of the problem within the Watkins Creek watershed is not entirely known. 2.3 Urban Stormwater Runoff Urban stormwater runoff is known to contain high levels of bacteria and is another potential contributor of E. coli to Watkins Creek. According to a study conducted by USGS5 median E. coli densities from six stream locations in MSD’s service area were strongly correlated with the percentage of upstream impervious cover. Runoff from both pervious and impervious areas has the potential to pick up and 3 United States of America and the State of Missouri, and the Missouri Coalition for the Environment Foundation v. Metropolitan St. Louis Sewer District, No. 4:07-CV-1120. 4 ETC Institute for Metropolitan St. Louis Sewer District. 2017. Metropolitan St. Louis Sewer District environmental awareness survey. ETC Institute. 47pp. 5 Wilkison, D.H., Davis, J.V. 2010. Occurrence and sources of Eschericia coli in metropolitan St. Louis streams, October 2004 through September 2007: U.S. Geological Survey Scientific Investigations Report 2010-5150. 57pp. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 9 transport bacteria from domestic and wild animal waste. Pet waste may enter local waterways from residential areas, as well as areas open to the public, such as dog parks, parks, trails, or other recreational areas utilized by pet owners. Wild animals like raccoons inhabiting the storm system or nuisance geese residing on local ponds are also potential sources. Additionally, bird droppings on roadways can easily be carried into the storm system and transported to streams during rain events. Waste from livestock, poultry, pets, and wildlife are all known to contribute to E. coli concentrations in urban streams. On average, 10 percent of E. coli in six metropolitan St. Louis streams was traced to dogs and another 20 percent to geese5. Note, this USGS5 study did not include data collected from Watkins Creek. Urban runoff discharges from the two MS4 permitted systems are considered potential point sources of E. coli to Watkins Creek. As previously discussed, the catchments that contribute stormwater runoff to the outfalls permitted under the MSD MS4 permit were not identified during development of the TMDL. Stormwater runoff from areas not served by the MS4s is considered a nonpoint source. However, the nonpoint source load allocation (LA) was not disaggregated from the MS4 WLA and no load allocations were assigned in the Watkins Creek bacteria TMDL. 2.4 Riparian Conditions Riparian conditions in the watershed were listed in the Watkins Creek bacteria TMDL as a likely source of bacteria. The riparian corridor of streams in the Watkins Creek watershed, extending 30-meters on each side of the channel, is predominantly urban. Notably, 45.9 percent of the land use is low-intensity urban, 37.2 percent is forest and woodland, 8.2 percent is grassland, and 3.7 percent is impervious1. Low- intensity urban land cover includes residential areas where bacteria loading from pet and wildlife waste can be picked up by stormwater runoff. Similarly, stormwater runoff from grassland cover in an urban setting may also contribute bacteria to Watkins Creek if it comes in contact with pet and wildlife waste. 2.5 Illicit Straight Pipe Discharges Illicit straight pipe discharges occur where household waste is discharged directly to a stream or area of land, and are different from illicitly connected sewers. Per the Watkins Creek bacteria TMDL, due to the presence of a sewerage system throughout the watershed, illicit straight pipe discharges are not expected to be significant contributors of E. coli. However, there is potential for private sewer laterals to fail on occasion and discharge sewage to waterways. Illicit discharges such as these have been found across MSD’s service area through Illicit Discharge Detection and Elimination work as required under Minimum Control Measure #3 of the MS4 permit. Discharges from failed sewer laterals are resolved by the homeowner, usually with partial funding assistance from a local lateral repair program. 3.0 TMDL Implementation Activities The implementation of activities provided in this ARAP will aim to reduce bacteria loading in Watkins Creek. In large part, those activities will be implemented through ongoing programs already being executed. The two main implementing programs are the St. Louis County Phase II Stormwater Management Plan (Third Term Permit 2017-2021) and Project Clear which addresses MSD’s consent decree obligations, established as part of the United States of America and the State of Missouri, and the Missouri Coalition for the Environment Foundation v. Metropolitan St. Louis Sewer District, No. 4:07- CV-1120. Additional activities beyond these two programs will harness information generated through existing MSD maintenance operations with the goal of developing and implementing further bacterial reduction. 3.1 St. Louis County Phase II Stormwater Management Plan The St. Louis County Phase II Stormwater Management Plan (Third Term Permit 2017-2021), referred to herein as the Stormwater Management Plan (SWMP), was developed in compliance with the MS4 permit issued to MSD and its co-permittees. The permit requires MS4s, MSD and its co-permittees, to implement activities via an iterative process to reduce the discharge of pollutants to the maximum extent MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 10 practicable (MEP) into the MS4 for the goal of attainment with Missouri’s Water Quality Standards. The SWMP, which was approved by MDNR on June 18, 2018, contains six minimum control measures (MCM) that include measurable activities for addressing requirements under Section 4.2 of the MS4 permit. Goals for each activity are set in each year of the permit, and annual reports are submitted to MDNR regarding the status of each goal. Goals are reviewed annually and the SWMP may be updated as needed or following renewal of the MS4 permit. Continued implementation of the SWMP through the iterative process will result in a significant reduction of pollutants discharged to waters in the plan area, including the discharge of E.coli bacteria to Watkins Creek. The result of implementing each activity will be reported through the SWMP annual reporting process. The following is a summary of SWMP activities expected to reduce bacteria contributions to Watkins Creek. Each activity references its corresponding goal in the SWMP. Prioritization activities, measurable goals, implementation schedules, and milestones for the activities described below will be consistent with those already identified in the SWMP. Please review the SWMP for a complete description of all activities under each MCM along with their schedule for implementation6. All activities in the SWMP shall be reviewed and evaluated for effectiveness at the end of year five of the MS4 permit to determine if they should be replaced or modified in the next permit cycle and SWMP. 3.1.1 MCM #1, Public Education and Outreach of Stormwater Impacts MSD and its co-permittees are required to implement a public education program to distribute educational material to the community or conduct equivalent outreach activities about the impact of stormwater discharges on waterbodies and steps the public can take to reduce pollutants in stormwater runoff. This program targets several pollutant sources that directly or indirectly address bacteria, including: pet waste; yard management; individual sewage disposal systems; land disturbance; and fats, oils, and grease (FOG). Under MCM#1, the current SWMP lists 16 individual activities that are intended to identify entities that may have an impact on stormwater, identify target audiences to foster nonpoint source pollution and water quality awareness, and ultimately increase awareness and positive behavior changes for those in the community. Of those 16 activities, 11 pertain to bacterial reduction and are noted as follows: 1. Collect a stormwater education survey to develop a baseline of water quality and nonpoint source pollution awareness and behaviors, and identify target audiences (Goal 6 of SWMP). The survey includes bacteria related topics such as the disposal of household cooking oils and grease, inspection and maintenance of septic systems, and disposal of pet waste. 2. Develop a database of all K-12 public and private schools in the plan area, which is to be used for outreach purposes and tracking schools that provide stormwater education (Goal 7 of SWMP). Bacterial pollution prevention is a component of stormwater education. 3. Develop and distribute stormwater messages to improve the public’s awareness of water quality protection (Goal 8 of SWMP). Messaging includes topics such as disposal of pet waste and maintenance of individual sewage disposal systems, both being potential sources of bacteria in the watershed. 4. Maintain and provide a library of stormwater education materials that can be used at public events and distributed to various audiences (Goal 9 of SWMP). Some of those materials will include information on bacteria pollution and prevention. 5. Provide presentations and educational materials to families and homeowners for the purpose of fostering nonpoint source pollution and water quality awareness (Goal 10 of SWMP). Presentations and educational materials will include information on bacteria pollution and prevention. 6 The SWMP is available on MSD’s website, www.stlmsd.com. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 11 6. Post pet waste signs in parks in order to foster nonpoint source pollution and water quality awareness (Goal 11 of SWMP). This effort will directly address pet waste as a source of bacteria. 7. Maintain a database of community partners with an interest in water pollution education for the purpose of fostering nonpoint source pollution and water quality awareness (Goal 12 of SWMP). Water pollution education will include information on bacteria pollution and prevention. 8. Provide educational materials to industrial entities, waste haulers, and food service establishments in order to foster nonpoint source pollution and water quality awareness in the community (Goal 13 of SWMP). Educational materials will include information on bacteria pollution and prevention. 9. Provide presentations and educational materials to trade associations, schools, and watershed groups (Goal 14 of SWMP). This activity will foster nonpoint source pollution and water quality awareness in the community and increase positive behavior change. Presentations and education materials will include information on bacteria pollution and prevention. 10. Partner with community organizations to provide stormwater information to a broad audience for the purpose of fostering nonpoint source pollution and water quality awareness, and increasing positive behavior change (Goal 15 of SWMP). Stormwater information will include topics associated with bacteria pollution and prevention. 11. Develop and advertise videos to be utilized in social media platforms (Goal 16 of SWMP). Messaging will include information on bacteria pollution and prevention. 3.1.2 MCM #2, Public Involvement and Participation Under MCM #2, MSD and its co-permittees implement a public involvement/participation program that provides opportunities for the public in development and oversight of the SWMP, as well as opportunities for involvement with the permittee’s renewal application. Collectively, there are 11 activities under MCM#2. Activities such as marking storm drains, distributing Enviroscape® watershed models for school presentations, participating in annual cleanup events, and providing resources to citizen volunteer organizations that promote green infrastructure and other healthy water programming ultimately improve nonpoint source pollution and water quality awareness. Of the 11 activities under MCM#2, there are five that pertain to bacterial reduction and are noted as follows: 1. Provide training to educators, watershed groups members, and others on how to use Enviroscape® watershed models with the purpose of engaging volunteers on how to educate students on sources of pollution and best practices (Goal 23 of SWMP). Training will include information on bacteria pollution and prevention. 2. Provide Enviroscape® watershed models for community use which will help foster nonpoint source pollution and water quality awareness (Goal 24 of SWMP). Pollution education will include information on bacterial pollution and best practices. 3. Provide stormwater drain marking instructions and supplies to volunteers in order to help foster nonpoint source pollution and water quality awareness (Goal 25 of SWMP). Inlet marking is intended to deter illegal dumping to the stormwater system, including material contaminated with bacteria such as pet waste. 4. Develop a storm drain marking map to help facilitate participation in drain marking opportunities (Goal 26 of SWMP). Improved participation will increase the number of marked drains and decrease illegal dumping, including those that may contain bacteria. 5. Provide resources to volunteer organizations that promote green infrastructure and other healthy water programming in order to foster nonpoint source pollution and water quality awareness (Goal 27 of SWMP). Efforts will include the distribution of educational material containing information on sources of bacteria and practices to reduce or prevent pollution. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 12 3.1.3 MCM #3, Illicit Discharge Detection and Elimination As part of MCM #3, MSD carries out an Illicit Discharge Detection and Elimination (IDDE) Program. An illicit discharge is any discharge to the stormwater system that is not composed entirely of stormwater, and may result from illegal dumping, a direct connection from the sanitary sewer to the storm sewer, or an indirect connection from improper surface discharges to the storm sewer. Under this program, MSD surveys all natural channels in the plan area at least once every five years, inspects outfalls for illicit discharges, responds to reports of illegal dumping, and conducts timely elimination of prohibited discharges. In the past, staff conducting illicit discharge surveys have discovered and eliminated illegal dumping of pet waste, leaking sewer lines, and failing private sewer laterals and onsite septic systems. MSD’s implementation of the IDDE program is expected to be one of the most impactful actions to improve water quality in the Watkins Creek watershed. There are 15 activities implemented under MCM #3, all of which either target sources of bacteria directly or facilitate the process of identifying and eliminating bacteria sources. Those activities are as follows: 1. Maintain a Geographic Information System (GIS) of stormwater outfalls and receiving streams (Goal 28 of SWMP). This GIS is used to locate and view outfalls in the plan area, and in the process identify and investigate sources of bacteria. 2. Provide map update work orders to track modifications to the sewer map for the purpose of maintaining current information on the storm sewer system in the plan area (Goal 29 of SWMP). This activity will improve the identification, tracking, and elimination of potential sources of bacteria. 3. Enforce MSD ordinance No. 15048, and others as required (Goal 30 of SWMP). Ordinance No. 15048 serves as MSD’s legal enforcement tool for eliminating prohibited discharges, including those that may be a source of bacteria. 4. Survey all natural channels identified in MSD’s stormwater GIS once every five years (Goal 31 of SWMP). This activity will lead to detecting and eliminating illicit discharges, including those that are a source of bacteria. 5. Respond to reports of illegal dumping, which will include detecting and eliminating sources of bacteria (Goal 32 of SWMP). 6. Maintain operating procedures for field testing and surveying to help identify chemicals indicative of illicit discharges (Goal 33 of SWMP). Field screening provides for timely and efficient illicit source identification and elimination, including sources of bacteria. 7. Maintain and annually review findings from channel surveys for the purpose of identifying priority areas for potential monitoring and follow-up work (Goal 34 of SWMP). This activity ensures there is follow-up on potential sources of pollutants to the stormwater system, including bacteria. 8. Review representative water quality data collected by MSD to prioritize investigation areas (Goal 35 of SWMP). Data is used to identify pollutant sources, including those for bacteria. 9. Develop a tabular database and GIS layer of areas that may utilize individual sewage disposal systems for the purpose of assisting with illicit discharge investigations (Goal 36 of SWMP). This activity directly pertains to bacteria as a pollutant. 10. Develop a tabular database and GIS layer of properties that have participated in a sewer lateral repair program in order to assist with illicit discharge investigations (Goal 37 of SWMP). This activity directly pertains to bacteria as a pollutant. 11. Maintain operating procedures for tracing illicit discharges from the public sewer system for the purpose of timely detection and elimination of pollutant sources, including those that are a source of bacteria (Goal 38 of SWMP). 12. Maintain operating procedures for the timely elimination of illicit discharges, including those that are a source of bacteria (Goal 39 of SWMP). MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 13 13. Maintain an enforcement plan for the timely elimination of illicit discharges, including those that are a source of bacteria (Goal 40 of SWMP). 14. Maintain and distribute brochures, door hangers, and other communication tools that inform about the hazards associated with illegal discharges and improper disposal of waste (Goal 41 of SWMP). The purpose of this activity is to foster stormwater nonpoint source pollution awareness and positive behavior change in the community, and it will address sources of bacteria. 15. Provide outreach communication tools to sources of non-stormwater discharges that could be substantial contributors of pollutants into the MS4, including bacteria (Goal 42 of SWMP). The purpose of this activity is to foster stormwater nonpoint source pollution awareness and positive behavior change in the community. Please note, information gathered for goals 35, 36, and 37 of the SWMP will also be used to support bacteria reduction strategies listed in Section 3.3 TMDL Best Management Practices Targeting Bacteria. 3.1.4 MCM #4, Construction Site Stormwater Runoff Control Under MCM #4, MSD and its co-permittees develop, implement, and enforce a program to reduce pollutants in any stormwater runoff to their regulated Small MS4 from construction activities that result in land disturbances greater than or equal to one acre. Reduction of stormwater discharges from a construction activity disturbing less than one acre is included in the program if that construction activity is part of a larger common plan of development or sale that would disturb one acre or more. Each incorporated municipality has the authority for construction permitting and inspection services. Some co-permittees provide full permitting and inspection services independently, while others have adopted St. Louis County’s ordinance and contract with St. Louis County Code Enforcement to meet permitting and inspection needs. While bacteria contributions from land disturbance sites is expected to be low, the potential for discharges of E. coli from sanitary facilities at construction sites is reduced through inspections and enforcement. There are eight individual activities implemented under MCM #4, of which five specifically relate to bacteria through retaining waste on site or by ensuring sediment and erosion controls are properly installed. Those five activities are as follows: 1. Maintain written procedures and guidance materials for operators to follow (Goal 45 of SWMP). This activity will help prevent sanitary waste from leaving the site and potentially entering a water course. 2. Maintain written procedures and guidance materials for permittees to follow (Goal 46 of SWMP). This activity will address bacteria by requiring development pre-construction planning and appropriate installation and maintenance of sanitary waste facilities. 3. Maintain written procedures to receive, respond to, and track public inquiries and complaints (Goal 47 of SWMP). This activity will address bacteria by providing timely responses to complaints of sanitary waste leaving a site. 4. Maintain written procedures and checklists for permittees to follow during SWPPP inspections (Goal 48 of SWMP). This activity will address bacteria by ensuring BMPs for sanitary waste facilities are properly installed and maintained. 5. Inspect land disturbance sites per land disturbance program ordinance (Goal 49 of SWMP). This activity will address bacteria by ensuring BMPs for sanitary waste facilities are properly installed and maintained. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 14 3.1.5 MCM #5, Post-Construction Stormwater Management in New Development and Redevelopment MSD and its co-permittees require developers to implement appropriate strategies and controls to address post-construction runoff from new development and redevelopment projects that disturb one acre of land or more, including projects less than one acre that are part of a larger common plan of development or sale. MSD and co-permittee ordinances ensure all applicable public and private development projects involving stormwater management are reviewed and approved by MSD. All projects are required to assess existing site conditions and identify sensitive areas and natural resources on site. The Rules and Regulations require that site designers prepare a site development plan that adequately protects sensitive areas and natural resources and does not generate unwarranted amounts of stormwater pollution. This plan may be based on the current version of the Site Design Guidance document on MSD’s website. Development sites regulated in the MS4 are required to apply strategies that reasonably mimic predevelopment runoff conditions by reducing runoff volume to calculated predevelopment levels. MSD requires all stormwater facilities to be provided and designed in accordance with provisions contained in the “Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and Stormwater Drainage Facilities,” as amended. The Bacteria and Nutrient Best Management Practice Strategy Review, conducted by Geosyntec Consultants and reported in a memorandum dated December 23, 2016 (Appendix B), evaluated MSD’s ongoing stormwater management facility selection based on bacteria and nutrient reduction effectiveness and helped characterize BMP implementation to the MEP. This review found that nearly 70% of built or planned structural facilities in the MS4 area scored high for removal of bacteria. Those structural facilities included bioretention basins, infiltration facilities, permeable pavements, and ponds. Continued implementation of these stormwater facilities and enhancements as recommended in the memorandum will help meet bacteria reduction targets. Maintenance responsibility for approved post-construction stormwater management facilities belongs to the owner. MSD’s authority to ensure stormwater facilities are maintained is covered under MSD Ordinance No. 15048. Owners submit annual reports on facility condition and MSD conducts inspections of each stormwater facility at least once every three years. There are eight activities implemented under MCM #5 in the current SWMP, all of which will help to reduce bacteria contamination of stormwater. Those activities are as follows: 1. Follow MSD and co-permittee ordinances, as well as MSD Rules and Regulations, which require developers and plan reviewers to implement appropriate strategies and controls to address post-construction runoff (Goal 51 of SWMP). Included among those strategies and controls, is the use of certain stormwater management facilities that remove bacteria from stormwater. 2. Follow the plan review process of executing maintenance agreements for the environmental compliance inspection process in order to ensure long-term operation of stormwater facilities, including those that remove bacteria (Goal 52 of SWMP). 3. Utilize the technology matrix in MSD’s stormwater management toolbox and maintain existing strategies (Goal 53 of SWMP). This activity will require developments to implement appropriate strategies and controls to address post-construction runoff, and will result in implementing activities to the MEP, including those that target bacteria. 4. Co-permittees will review and update parking ordinances and/or policies as needed in order to reduce impervious parking areas and barriers to incorporating green infrastructure (Goal 54 of SWMP). This activity will optimize use of pervious areas, helping to remove bacteria from stormwater. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 15 5. Maintain an optional conceptual review process to provide developers with a plan review assessment of appropriate strategies and controls to address post-construction runoff (Goal 55 of SWMP). This activity will identify opportunities for water quality protection, including identifying stormwater facilities that can help remove bacteria early in the project planning phase. 6. Make the Site Design Guidance document available to provide developers and plan reviewers a way to implement effective stormwater management controls (Goal 56 of SWMP). This activity will lead to utilizing effective stormwater facilities, protecting sensitive areas, and help to remove bacteria from stormwater. 7. Use pre-condition assessment with early stage project planning which will lead to utilizing effective stormwater facilities, protecting sensitive areas, and help to remove bacteria from stormwater (Goal 57 of SWMP). 8. Inspect all water quality stormwater facilities utilizing key performance indicators to demonstrate compliance (Goal 58 of SWMP). This activity will ensure the long term operation of stormwater facilities, including those that remove bacteria from stormwater. 3.1.6 MCM #6, Pollution Prevention Good Housekeeping for Municipal Operations Under MCM #6, MSD and its co-permittees implement an operation and maintenance program that includes a training component and has the ultimate goal of preventing or reducing pollutant runoff from municipal operations. Common municipal operations that are addressed by an Operations and Maintenance Program include: general housekeeping and operation and maintenance; vehicle/equipment repair and maintenance operations; vehicle/equipment washing; facility repair, remodeling, and construction; cleaning and maintenance of roadways, highways, bridges, and parking facilities; maintenance of parks, green spaces, trails, and landscaping; cleaning and maintenance of drainage channels, storm sewers, and inlet structures; operation and maintenance of recycling facilities; and, water quality impact assessment of flood management projects. Written Operation and Maintenance Program procedures help to ensure pollution controls are properly installed and maintained. Training provided to staff covers pollution prevention and control techniques that may apply to the municipal operations noted above, as well as identifying and reporting illicit discharges. There are 10 specific activities included under MCM #6 in the SWMP, and three of those help to reduce bacteria in stormwater. Those activities are as follows: 1. Provide training to all MSD and co-permittee employees who work in municipal operations impacted by stormwater in order to prevent and reduce stormwater pollution from municipal operations (Goal 59 of SWMP). Training includes information on reporting illicit discharges such as failing septic systems, which will help to reduce bacteria in stormwater. 2. Install stormwater facilities with the construction of municipal buildings and roadways, where feasible, for the purpose of providing pollutant controls (Goal 63 of SWMP). Certain facilities will help remove bacteria from stormwater. 3. MSD and all co-permittees are to maintain a written Operation and Maintenance Program to prevent and reduce runoff from municipal operations (Goal 65 of SWMP). The written program includes guidelines for posting pet waste signs in public parks and maintaining disposal stations, which will help to reduce bacteria in stormwater. 3.2 Project Clear MSD’s implementation of Project Clear has and will continue to result in reduced bacteria loading to Watkins Creek. Project Clear is a long-term effort by the Metropolitan St. Louis Sewer District (MSD) that focuses on three categories of work: get the rain out; repair and maintain; and building system improvements. Get the rain out focuses on preventing excess stormwater from entering the sewer system through a variety of project types, including downspout disconnections, and rainscaping. Repair and maintain continues the work MSD has done to repair, maintain, and renew the existing sewer system, on a MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 16 faster timeline. Building system improvements involves new construction of wastewater management structures, including deep underground tunnels and above-ground storage tanks. Project Clear activities meet obligations required under the federal consent decree. Among those obligations, MSD must eliminate all constructed sanitary sewer overflow outfalls no later than December 31, 20337. Other Project Clear strategies that involve sewer inspection, maintenance, and repair and rehabilitation will reduce occurrences of sanitary sewer overflows as well. The following sections describe MSD’s work under Project Clear and the federal consent decree that will address bacteria loading in Watkins Creek. 3.2.1 Sanitary Sewer Overflow Control Master Plan MSD’s SSO Control Master Plan developed in compliance with the consent decree describes specific measures that will result in the elimination of all constructed SSO outfalls, all known SSOs, building backups, and/or that are necessary to ensure there is adequate capacity in the sanitary sewer system to collect, convey, and treat anticipated wet weather flows under current and projected future conditions. Remedial measures used to address capacity limitations and eliminate bypassing may include the removal of I/I sources and increases in the capacities of sewer pipes, force mains, and pump stations. The SSO Control Master Plan is required to eliminate 85% of the constructed SSO outfalls by December 31, 2023. Elimination of up to 15% of the constructed SSO outfalls may occur after December 31, 2023, but all must be completed no later than December 31, 2033. 3.2.1.1 Sewer System Evaluation Survey (SSES) As part of the SSO Control Master Plan, MSD performed a SSES for the Watkins Creek watershed8. The purpose of the SSES was to identify 1) areas with excessive inflow/infiltration (I/I) causing or contributing to SSOs and building backups, 2) known SSOs within the watershed, 3) physical conditions and design constraints of pump stations and force mains that contribute to SSOs and building backups, 4) physical and/or structural conditions of pipes, manholes, and structures in the sanitary sewer system that contribute to SSOs and building backups, 5) sources of I/I determined to have excessive I/I rates, and 6) stormwater cross connections and discovered unauthorized direct connections. The SSES identified 8 I/I study areas in Watkins Creek watershed. Study areas were ranked and prioritized by the existence of constructed SSOs, number of insurance claims, number of service requests, water quality impacts, and I/I estimates from models. One high priority study area, an area with excessive I/I causing or contributing to sanitary sewer overflows and building backups, was identified in the southeast portion of the watershed. Remaining study areas did not meet high priority ranking requirements. Based on the age of housing and building information, some of the sanitary sewers in the watershed were built in the early 20th century, but most were constructed after 1940. Many of the sanitary sewers in the west portion of Watkins Creek watershed, particularly west of Lewis and Clark Boulevard were constructed from 1966-1985. East of Lewis and Clark Boulevard, sanitary sewers were mostly constructed from 1941-1965 and 1966-1985. Vitrified clay, plastic, and reinforced/non-reinforced concrete were the three most common materials used for pipe construction. Recently obtained pipe material data is shown in Tables 2 and 3 of this report. 7 MSD’s consent decree was amended on June 22, 2018. This amendment extended the construction schedule for certain combined sewer overflow storage tunnels in the River Des Peres watershed by five years. MSD also agreed to invest $20 million in green infrastructure in its Lemay Service Area/River Des Peres Watershed. 8 Metropolitan St. Louis Sewer District. 2013. Watkins Creek watershed sewer system evaluation survey. Completed December 31, 2013. 240pp. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 17 Physical/structural condition and design constraints of sanitary sewer infrastructure were described in the SSES report. At the time of the SSES report, there was one pump stations in the watershed owned by MSD. This pump station had onsite backup power, but did not have storage capacity. There were no design constraints associated with any of the force mains. CCTV investigations of 128 sewer reaches, comprising 8% of the sewers in the watershed, were carried out in suspected problems areas (thus are not indicative of the entire watershed). Of the sewer reaches that were televised, just over 45% had major or moderate structural issues or root intrusion. Studies conducted in the single high priority area of the watershed attributed I/I sources to both public and private defects. Public defects are found on sewers and manholes located on public ground or easement and maintained by MSD. Private defects are found on private property. Public defects included indirect connections, mainline defects, manhole cover defects, manhole frame defects, and manhole structure defects. There were no direct connections among the public defect findings. Private sources of I/I were the result of connected downspouts, and defective cleanouts, laterals, and drains (i.e. yard drains, driveway drains, basement entry drains, foundation drains, etc.). There were no private defects attributed to plumbing inside buildings. Overall, most defects in the study were the result of defective cleanouts, defective manhole covers, and defective manhole frames. Defect categories that may have the greatest impact on wet weather flows (average flow per defect) associated with the overall I/I included connected downspouts, indirect connections, and private drains. The SSES report for Watkins Creek watershed contains a complete summary of I/I estimated flows and attributed sewer defects. 3.2.1.2 Master Plan Projects As a result of the SSES, seven SSO Control Master Plan projects were originally scheduled in the Watkins Creek watershed. Appendix A includes a table with all SSO Control Master Plan projects for Watkins Creek watershed. Projects listed in the table include schedules for the Master Plan projects as well as schedules for their public and private portions. Public and private work includes remedial measures to address their respective defects as described in the previous section and SSES report. All work is routinely scheduled ahead of Master Plan dates to ensure compliance with timelines in MSD’s consent decree. Two projects in the SSO Control Master Plan for Watkins Creek watershed address sewers affected by either public or private I/I, or both. The purpose of I/I reduction is to repair and replace public and private sewers where inflow and infiltration cause or contribute to SSOs or building backups. Inflow occurs when stormwater enters the sanitary sewer through direct connections. Sources of inflow can include connections from roof drains, defective laterals and lateral cleanouts, and other drains for yards, driveways, basement entries, foundations, etc. Infiltration refers to groundwater that enters the sanitary sewer system through cracks and other openings in defective or deteriorated sewers. Cracks or openings may be caused by age related deterioration, loose joints, installation errors, damage, or root infiltration. Inflow and infiltration sources influence sewer flows differently during storm events, with inflow impacting the sewer immediately and infiltration impacting the sewer over an extended period of time. Four projects include a specific phase to address sanitary relief. The purpose of sanitary relief is to increase the capacity of the sewer to handle wet weather peak flows without experiencing surcharging sufficient to cause SSOs, including causing failure of the largest pump in any pumping station and/or primary power failure to any pumping station. One additional SSO Control Master Plan project in Watkins Creek watershed, Watkins Creek Pump Station (P-101) Improvements, will involve relocating the existing pump station and constructing a new one. In addition, this project will include construction for a new force main. The original project scope involved construction of 16,000 feet of 12-ft diameter deep tunnel and was planned for completion in 2032. The current project scope allows work to be completed as earlier as 2022. This change in schedule MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 18 was used to plan activities described in Section 3.3 TMDL Best Management Practices Targeting Bacteria. Of the seven SSO Control Master Plan Projects, Bissell Point Service Area I/I Removal-SubTrunk #3 Lateral and Sub-Trunk #2 Lateral Sanitary Relief are projects that have already been completed. The remaining Master Plan projects are scheduled for anticipated completion from 2021 through 2029. These projects will eliminate the remaining constructed SSOs, improve sewer capacity, or correct defects and eliminate sources of I/I which deprive the system of capacity. Of the five existing constructed SSOs, BP- 210, BP-211, and BP-213 are to be removed under Sub-Trunk #2 Sanitary Relief (Birmingham Ct to Cove Ln). Constructed SSO BP-214 is to be removed under Sub-Trunk #3 Sanitary Relief (Muriel Dr to Jenner Ln). Constructed SSO BP-640 located in the central region of Watkins Creek watershed, will be removed during the Carson Villa I/I Reduction (Marcella Ave and Wales Ave) project which is actually included in the SSO Control Master Plan for Maline Creek rather than Watkins. These five existing constructed SSOs are scheduled to be eliminated over the period of 2019-2023 per MSD’s Project Clear program. By completing Master Plan projects the frequency of SSO occurrences and the release of bacteria into Watkins Creek watershed will be reduced. The status of projects listed in Appendix A will be submitted with the SWMP Annual report. 3.2.2 Capacity, Management, Operations, and Maintenance Program MSD’s Capacity, Management, Operations, and Maintenance (CMOM) Program operates with goal of maintaining established service levels and minimum performance standards. MSD’s CMOM Program conducts the following activities: 1. Inspects 280 miles of sanitary sewer by CCTV each year, and annually reports location and number of miles of sewer pipe inspected. 2. Acoustically inspects all sewers 15 inches or less in the separate system on a six year cycle. All sewers that score an acoustic inspection rating of 0 to 5 will be cleaned. Clean all sewers greater than 15 inches and less than or equal to 21 inches in the separate system on a six year cycle. Clean all sewers less than or equal to 21 inches in the combined system on a five year cycle. Clean all sewers greater than 21 inches as needed. MSD annually reports the number of miles and locations of all sewer pipes that are acoustically inspected or cleaned. 3. Inspects 15,000 manholes annually and performs manhole frame adjustments as needed (there is no yearly target for manhole frame adjustments), and performs repairs, rehabilitations, and/or replacements on all manholes with a condition rating of 4 or 5 within one year of discovery. MSD annually reports locations and number of manholes inspected, total number of manhole frame adjustments performed, and manholes that were permanently repaired/rehabilitated/replaced. 4. Permanently repairs, rehabilitates, and/or replaces at least 90 miles of sewer pipe each year (the target of 90 miles will be reduced to 65 miles in 2022), and repairs all acute defects within one year of discovery. MSD annually reports the locations and number of miles of sewer pipes that were repaired/rehabilitated/replaced, as well as the locations and number of acute defects that were repaired. 5. Inspects all 271 pump stations. Inspection frequency is no less than monthly for all collection system pump stations, no less than twice per month for pump stations between 1 million gallons per day (MGD) to 5 MGD in peak hydraulic capacity, and no less than weekly for pump stations greater than 5 MGD in peak hydraulic capacity. Overflow Regulation Systems (ORS) and Relief pump stations are inspected no less than monthly regardless of capacity. Collectively, MSD is required to perform 3,905 pump station inspections each year. MSD annually reports the number of inspections for each pump station as well as its capacity range. 6. Visual inspections and non-destructive testing of force mains. Force mains categorized as high- risk are inspected visually each year and by non-destructive testing once every three years. Force MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 19 mains categorized as medium-risk are inspected visually once every two years and by non- destructive testing once every six years. Force mains categorized as low-risk are inspected visually once every five years. All defects discovered during inspection and testing are repaired within one year. MSD annually reports locations and numbers of force main assets in each risk category that have undergone visual inspection, non-destructive testing, and have been repaired/replaced per risk. CMOM activities will be carried out within the Watkins Creek watershed and can be expected to contribute to reduced bacteria loading. CMOM activities will be reported as required under MSD’s consent decree, and will not be reported as part of this ARAP. Implementation of BMP #4 in Section 3.3 TMDL Best Management Practices Targeting Bacteria however, may help detect the CMOM Program Plan’s impact on bacteria loading to Watkins Creek. 3.2.3 Fats, Oil, and Grease Program The consent decree also includes requirements for MSD to control fats, oil, and grease (FOG) to ensure their accumulations are not restricting the capacity of the sewer system and causing sanitary sewer overflows. Under the FOG Control Program Plan, MSD identifies and inspects commercial establishments/food service establishments (FSEs) and industrial facilities prone to FOG accumulations. Facilities located in problem areas with reoccurring grease blockages that result in SSOs or in areas with collection system defects are inspected on a periodic schedule with greater frequency (i.e. quarterly, semi- annual, or annual). Routine periodic FSE inspections of FOG equipment are conducted every two to five years when the sewer is in a moderate to low risk area. FSE inspection frequency may be greater than five years in low risk areas with exceptionally large diameter sewer pipes. Other FSE inspections can occur in response to FOG related complaints, or more randomly when investigators notice a new facility while in the field, or if an existing facility has undergone a name change. Within MSD’s service area there are approximately 4,400 facilities having the potential to discharge significant amounts of FOG into the sanitary sewer system. Within the Watkins Creek watershed, there are 42 active FSEs and five that are listed as having been decommissioned9. Between 2016 and 2018, 62 FSE inspections were performed without any failures or need to take enforcement action. Over this same period, no sanitary sewer overflows were found to be caused by grease blockages. Overtime, FOG activities are expected to reduce grease related sanitary sewer overflows and related bacteria loading to Watkins Creek. FSE inspections and enforcement actions are reported annually under MSD’s consent decree, and thus will not be reported in this ARAP. Instead, implementation of BMP #4 in Section 3.3 TMDL Best Management Practices Targeting Bacteria, may help detect the FOG Program’s impact on bacteria loading to Watkins Creek. 3.3 TMDL Best Management Practices Targeting Bacteria Beyond activities carried out under the SWMP and MSD’s consent decree, specific TMDL BMPs will be implemented in order to further reduce the bacteria loading in Watkins Creek. These BMPs are specifically designed to improve the monitoring and management of potential sources of bacteria in the watershed. TMDL BMPs are shown in Table 5, and are set to begin the first year following removal of the last constructed SSO, which is tentatively 2024. Removal of the last constructed SSOs in the Watkins Creek watershed will be accomplished by Sub-Trunk #2 Sanitary Relief (Birmingham Ct to Cove Ln). This project will eliminate constructed SSOs BP-210, BP-211, and BP-213. Per the Consent Decree, Sub-Trunk #2 Sanitary Relief (Birmingham Ct to Cove Ln) has a scheduled completion date of no later than April 11, 2023. Activities of this ARAP as outlined in Table 5 shall commence in 2024. Thereafter, 9 FSE data regarding active and decommissioned establishments was obtained on 2/22/2019. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 20 activities are scheduled by MS4 operating permit year where applicable and are planned through 2029, aligning with the implementation schedule of SSO Control Master Plan projects within Watkins Creek watershed. In the interim, similar ARAP activities will have already been conducted in the Fishpot Creek Watershed. This will lend valuable experience and other “lessons learned” which can be harnessed to ensure that effective approaches are implemented not only in Watkins Creek but other watersheds subject to future TMDL ARAPs. Among the seven TMDL BMPs listed in Table 5, BMPs will include visual inspections of the storm sewer to identify potential sources of bacteria (TMDL BMP #2) and subsequent response efforts to eliminate those sources that have been confirmed (TMDL BMP #3). Currently MSD utilizes crawl crews and CCTV inspections to inspect and assess the condition of large and small storm sewer systems. Findings from these inspections will include the location of direct connections into storm sewer mains, inlets, and manholes. Where private connections are discovered, they will be reported to MSD’s Division of Environmental Compliance to investigate for and identify sources of E. coli bacteria that feed into the private storm sewer connections. Based on the findings of the investigations, appropriate action will be taken to eliminate discovered sources of E. coli bacteria associated with the connection. For instance, this could be an improperly connected house lateral, septic system, or a drainage area served by a drain that is populated by pet owners or livestock. Work pertaining to TMDL BMPs #2 and #3 is currently scheduled through 2029. Data obtained from visual inspections of the storm sewer system, including but not limited to CCTV and crawl crew inspections, conducted under the Fishpot Creek bacterial TMDL ARAP will be used to evaluate the effectiveness of visual storm sewer inspections overall and help determine the best methods for this activity in Watkins Creek and other watersheds with approved TMDLs for bacteria. It is anticipated that visual storm sewer inspections will be improved and refined over time, becoming more effective at identifying and eliminating bacteria sources. While TMDL BMPs #2 and #3 are planned though 2029, they may be completed ahead of schedule or remain ongoing. In accordance with MS4 Permit Sections 3.1.3.3 and 3.1.3.4, TMDL BMPs listed in Table 5 of this section will be implemented according to the provided schedule only after this TMDL ARAP receives MDNR’s approval. Therefore, MSD respectfully requests MDNR’s approval of this TMDL ARAP. Implementation activities in the SWMP and MSD’s consent decree will be carried out according to their previously determined and ongoing schedules. All TMDL BMPs shall be reviewed and evaluated for effectiveness at the end of year five of the MS4 permit, and at the end of 2029 following completion of SSO Control Master Plan projects in the Watkins Creek watershed, in order to determine if they should be replaced or modified. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 21 Table 5. TMDL Best Management Practices Targeting Bacteria in the Watkins Creek Watershed. 1BMP is based on outcome of SWMP BMP #36. The map will be used for channel inspections conducted in the fourth term MS4 permit. 2BMP is based on outcome of SWMP BMP #37. 3 Last constructed SSOs (BP-210, BP-211, and BP-213) are scheduled for removal no later than 4/11/2023 by Sub-Trunk #2 Sanitary Relief (Birmingham Ct to Cove Ln). ARAP Commences in year 2024. 4Denotes period for iterative review of BMP effectiveness. # BMP Description BMP Purpose Expected Result of BMP Measurable Goals and Milestone Dates Permit Year 3, 2019 Permit Year 4, 2020 Permit Year 5, 2021 2022 2023 20243 2025 2026 2027 2028 20294 BMP Evaluation Process/Criteria 1 Determine extent of rehabilitated sewers along Watkins Creek and tributaries. Compare to in- stream E.coli data. Identify extent and percent of rehabbed sewers within defined proximity to Watkins Creek and tributaries. Identify potential relationships with instream E. coli and need for sewer rehabilitation work. Map and summary table of rehabbed sewers within defined proximity to Watkins Creek and tributaries. None None None None None Generate map and summary table. Generate map and summary table. Generate map and summary table. Generate map and summary table. Generate map and summary table. Generate map and summary table. Map and summary table developed and updated. 2 Identify potential sources of bacteria through visual inspections of the storm sewer system. Identify sources of bacteria to Watkins Creek. Summary of bacteria findings. None None None None None Commence visual inspections. Report findings from 2024. Continue visual inspections. Report findings from 2025. Continue visual inspections. Report findings from 2026. Continue visual inspections. Report findings from 2027. Continue visual inspections. Report findings from 2028. Continue visual inspections. Summary table with bacteria findings developed. 3 Respond to or eliminate potential human related sources of bacteria identified through visual inspections of the storm sewer systems. Reduce bacteria loading to Watkins Creek. Summary of response actions. None None None None None Respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Report 2024 response actions. Continue to respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Report 2025 response actions. Continue to respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Report 2026 response actions. Continue to respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Report 2027 response actions. Continue to respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Report 2028 response actions. Continue to respond to bacteria findings and eliminate illicit discharges identified during visual inspections. Summary table with response actions developed. 4 Assess E. coli data collected by MSD in previous year and evaluate loading and trends. Track E. coli levels and bacteria loading. Summary table with E. coli measurements, loading rates, and trends. None None None None None Summarize 2023 E. coli loading and trend. Summarize 2024 E. coli loading and trend. Summarize 2025 E. coli loading and trend. Summarize 2026 E. coli loading and trend. Summarize 2027 E. coli loading and trend. Summarize 2028 E. coli loading and trend. Summary table with E. coli measurements, loading rates, and trend developed and updated. 51 Update database of properties that may utilize an individual sewage disposal system in Watkins Creek watershed. Have a database of properties that may have an individual sewage disposal system to identify potential sources of bacteria. Map and list of properties with an individual sewage disposal system. None None None None None Develop map and list of properties. None None None None None Map and list of properties with an individual sewage disposal system developed. 62 Update database of properties that participated in a sewer lateral repair program in Watkins Creek watershed. Track improvements to problematic infrastructure and elimination of potential sources of bacteria. Have a database of properties that participated in a lateral repair program. None None None None None Develop map and list of properties. None None None None None Map and list of properties with repaired sewer laterals developed. 7 Summarize maintenance of individual sewage disposal systems documented by MSD’s Hauled Waste Program. Have a list of properties that maintain their individual sewage disposal system. Develop a list of properties that maintain their individual sewage disposal system. None None None None None Obtain 2023 records from Hauled Waste Program, add to list, and report. Obtain 2024 records from Hauled Waste Program, add to list, and report. Obtain 2025 records from Hauled Waste Program, add to list, and report. Obtain 2026 records from Hauled Waste Program, add to list, and report. Obtain 2027 records from Hauled Waste Program, add to list, and report. Obtain 2028 records from Hauled Waste Program, add to list, and report. List of properties that maintain their individual sewage disposal system developed. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP 22 4.0 Evaluation Activities described in this TMDL ARAP will target bacteria sources in Watkins Creek and aim to reduce the overall bacteria load contributing to its impaired status. All activities will be carried out through implementation of the SWMP, Project Clear and the federal consent decree, or as scheduled in Section 3.3 of this document, TMDL Best Management Practices Targeting Bacteria. TMDL BMPs listed in Section 3.3 of this document will be implemented according to the schedule found in Table 5. TMDL BMPs #2 and #3 are scheduled through 2029, but with information gathered under the Fishpot Creek bacteria TMDL ARAP, both BMPs may be completed ahead of schedule or remain ongoing in order to maximize the effectiveness of visual storm sewer inspections at identifying and eliminating sources of bacteria. Each TMDL BMP shall be reviewed and evaluated for effectiveness as described earlier to determine if they should be replaced or modified in order to achieve further progress towards reducing the bacteria load to Watkins Creek. TMDL BMP effectiveness will be largely based on water quality data as evaluated under TMDL BMP #4. As appropriate, the status of each TMDL BMP will accompany the annual SWMP report. With the implementation of the Fishpot Creek Watershed ARAP commencing prior to this watershed, opportunities for “lessons learned” exist. The outcomes of the pilot efforts accomplished in the Fishpot Creek watershed may be considered for implementation into this ARAP, either as a modification to a proposed activity or an additional activity. Such changes to this ARAP could occur either prior to, or after its commencement, and would be subject to MDNR approval. In line with MS4 Permit Section 3.1.2.1, implementation of the Watkins Creek Bacteria TMDL ARAP will be completed as soon as practicable, but is anticipated to span years or even multiple permit terms. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP Appendix A SSO Control Master Plan Projects in the Watkins Creek Watershed MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP Project Name Plan/Phase Project Description Initial Design Commence - Complete Construction Bissell Point Service Area I/I Removal- SubTrunk #3 Lateral Master Plan Rehab of public sewers and removal of private I/I sources from sanitary sewers. 8/31/2014 2/16/2017 - 2/11/2018 Public I&I Rehab of public sewers to reduce I&I. 8/5/2014 9/15/2015 - 1/02/2019 Sub-Trunk #2 Lateral Sanitary Relief Master Plan Remove private and public I/I sources from sanitary sewers. 12/31/2013 2/7/2016 - 2/11/2017 Public I&I Rehab of public sewers to reduce I&I. 8/22/2013 1/21/2015 - 2/6/2017 Private I&I Red. Private I&I 8/22/2013 7/13/2015 - 4/11/2016 Sub-Trunk #2 Sanitary Relief (Birmingham Ct to Cove Ln) Master Plan Construct 4,400 ft. of 18 in. to 21 in. sanitary sewer. 5/2/2019 10/18/2021 - 4/11/2023 Public Sanitary Relief Pipe Construction 8/22/2018 6/21/2021 - 6/21/2023 Sub-Trunk #3 Sanitary Relief (Muriel Dr to Jenner Ln) Master Plan Construct 4,300 ft. of 8-in to 27 in. sanitary sewer. 8/31/2015 2/16/2018 - 8/10/2019 Public Sanitary Relief Pipe Construction 8/22/2018 6/27/2021 - 12/29/2022 Watkins Creek Pump Station (P-101) Improvements Master Plan Master Plan called for 16,000 ft. of 12 ft. diameter deep tunnel. However, current approach is to relocate pump station out of floodplain and construct a new forcemain. 8/31/2024 8/10/2028 - 10/18/2032 Pump Station Improvements Relocate and construct new pump station out of floodplain. 10/31/2016 5/4/2021 - 5/14/2022 Force Main Construction Construct 10,100 ft. of 20 in. forcemain. 10/12/2018 3/10/2020 - 3/20/2021 Watkins Creek Sanitary Relief (Kenran Industrial Blvd to Farm Pond Ct) Master Plan Construct 18,000 ft. of 15 in. to 36 in. sanitary sewers 7/4/2024 6/19/2027 - 12/5/2029 Public Sanitary Relief Pipe Construction 9/1/2023 2/18/2027 - 8/16/2029 Sub-Trunk #11 Sanitary Relief (Belgrove Dr to Lothian Cir) Master Plan Construct 1,100 ft. of 12 in. sanitary sewers FY 2024* FY 2026* Public Sanitary Relief Pipe Construction FY 2024* FY 2026* * Indicates best available dates. FY represents fiscal year. MSD’s fiscal year is July 1 through June 30. MSD & MS4 Co-permittees Watkins Creek bacteria TMDL ARAP Appendix B Bacteria and Nutrient Best Management Practices Strategy Review 2009 East McCarty Street, Suite 1 Jefferson City, Missouri 65101 PH 573.443.4100 FAX 573.443.4140 www.geosyntec.com Memorandum Date: December 23, 2016 To: Jay Hoskins, Metropolitan St. Louis Sewer District From: Avery Blackwell, P.E., Brandon Steets, P.E., Scott Struck, P.E., Dan Pankani, P.E. Geosyntec Consultants Eric Dove, David Carani, HDR Subject: Bacteria and Nutrient Best Management Practice Strategy Review Geosyntec Project: MOW5165E Phase 90 Attachments: Attachment A - BMP Evaluation Results Recent actions by the Missouri Department of Natural Resources (MDNR) will impact how the Metropolitan St. Louis Sewer District (MSD) administers their stormwater management program. These actions include publication of the Missouri Nutrient Loss Reduction Strategy1, completion of Escherichia coli (E. coli or bacteria) total maximum daily loads (TMDLs) for four streams in the St. Louis area2, and renewal of the statewide small municipal separate storm sewer system (MS4) general permit (MOR-040000). Central to each of these actions is the requirement for MS4 programs to implement best management practices (BMPs) via an iterative process to reduce the discharge of pollutants into the MS4 to the maximum extent practicable (MEP). The purpose of this memo is to briefly outline these recent MDNR actions and potential MS4 program impacts, generally characterize MSD’s existing structural and non-structural BMPs for bacteria and nutrients relative to the state of the practice and other MS4 programs, and recommend actions that MSD could pursue to further identify areas to enhance BMP implementation. The results of this review are intended to help MSD characterize MEP for controlling bacteria and nutrients in stormwater runoff. 1 http://dnr.mo.gov/env/wpp/mnrsc/docs/nlrs-strategy-2014.pdf 2 TMDLs for Coldwater Creek, Creve Coeur Creek, Fishpot Creek, and Watkins Creek were approved by EPA on July 13, 2016. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 2 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo REGULATORY CONTEXT As mentioned above, the Missouri Nutrient Loss Reduction Strategy (Nutrient Strategy), recently approved bacteria TMDLs, and the newly-issued small MS4 general permit each require MSD to evaluate current approaches for defining MEP. Evaluating approaches for defining MEP for controlling bacteria and nutrient levels in a comprehensive fashion will assist MSD in determining how best to define MEP. A brief description of these MDNR initiatives and their impact on MSD’s stormwater management program are outlined below. In December 2014, MDNR finalized the Nutrient Strategy which outlines a set of recommended actions that MS4s and other nutrient sources could implement to reduce nutrient loads to the Gulf of Mexico. Available data (provided by MSD) suggest that MS4s are a relatively minor source of nutrients to the Gulf and that additional data are needed to characterize urban stormwater loads. The Nutrient Strategy also acknowledges the role of state-mandated funding limitations for stormwater programs, and the need for an interactive, efficient, and cost-effective approach to address MS4 nutrients. To that end, the Nutrient Strategy identifies several actions that MS4 agencies should complete over a five-year period (2015-2019) to better characterize their programs and define MEP in the context of nutrient reductions. These include the following: • From 2015 to 2017, review public involvement and education programs and material and make recommendations for enhancements to implement in 2018-2019 consistent with available funding. • From 2015 to 2019, review programs and identify appropriate structural and non- structural BMP enhancements to implement in 2020 and beyond consistent with available funding. At a minimum, MS4 agencies should consider how low-impact development practices might improve nutrient management effectiveness. In January 2015, MDNR finalized E. coli TMDLs for four streams in the St. Louis area; EPA subsequently approved the TMDLs in July of 2016. These TMDLs identified MSD and several of the MS4 co-permittees as point source contributors of bacteria in the watersheds. As MDNR stated in the “Reasonable Assurance” section of each TMDL, “The wasteload allocations for MS4s will be implemented through the NPDES MS4 permits with the ultimate goal to employ an iterative process using BMPs to the MEP, assessment, and refocused BMPs to the MEP, leading toward attainment of water quality standards (64 FR 68753)”. In the implementation plan, which accompanied each TMDL, MDNR discussed MS4 stormwater management plan requirements to address the six minimum control measures (MCM), and reiterated that BMPs and programs developed under the MCMs are expected to result in bacteria reductions from the MS4 area. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 3 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Since 2013, MDNR has also been working closely with stakeholders, including MSD, to revise and reissue the statewide Phase II MS4 general permit. The permit was issued by MDNR on October 1, 2016. The permit includes clarifying language that MS4 discharge limits are defined as BMPs to the MEP. More specifically, Section 1.4.1 of the permit states, “The permittee shall implement Best Management Practices (BMPs) via an iterative process to reduce the discharge of pollutants to the Maximum Extent Practicable (MEP) into the MS4 for the goal of attainment with Missouri’s Water Quality Standards…” The permit also includes new requirements for MS4 that are subject to a TMDL. These requirements include developing a TMDL Assumptions and Requirements Attainment Plan (ARAP) that includes, among other things, a process to identify specific BMPs to address TMDL pollutants, prioritized actions, and an implementation schedule. STRUCTURAL BACTERIA AND NUTRIENT BMP EVALUATION Structural BMPs Evaluated MSD requires new and redevelopment projects to submit a Stormwater Management Facilities BMP Operation and Maintenance Design Report and Plan for approval. According to MSD’s Small MS4 2015-16 Annual Report (Annual Report), since implementation of these new water quality BMP requirements in October 2006, 1,286 projects representing 4,516 BMPs have been constructed, permitted for construction, or are under review by MSD’s Planning Division. According to the Annual Report, bioretention (48%) was by far the most common BMP implemented (Figure 1). Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 4 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Figure 1. Post-Construction BMPs Built, Permitted for Construction, or Under Review as of 6/16/2016 (from the Annual Report). Of the 4,516 BMPs, nearly half were bioretention In addition to the structural BMPs identified in the Annual Report (Figure 1), this evaluation included three common Post-Construction Ordinances: stream buffers, tree preservation, and impervious area reduction. Also, two advanced structural BMPs designed specifically for treating bacteria and nutrients were evaluated. These advanced structural BMPs included enhanced biofilters3 and subsurface flow wetlands4. 3 Enhanced biofilters are defined here as vegetated media filters (or bioretention with underdrains) that incorporate the following design enhancements that have been shown to improve bacteria reduction relative to standard biofilters: • Media amendments such as biochar and coconut coir that have been shown to enhance bacteria removal; • Vegetation that is shown to enhance bacteria removal and support media aeration while reducing potential for short circuiting or underdrain clogging; • Outlet control for enhanced contact time; and • A saturated zone. 4 Subsurface flow wetlands are engineered, below-ground horizontal flow treatment wetlands that include many of the natural treatment processes of surface flow constructed wetlands as well as the filtration mechanisms of media filters. Water flows through a granular matrix, which typically supports the growth of emergent wetland vegetation on the surface. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 5 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Relative Benefit Rankings for Structural BMPs To evaluate bacteria and nutrient reduction effectiveness of ongoing structural BMP implementation, the BMP categories were compared using a relative scoring system based on weighting factors derived from previous BMP implementation planning experience, along with feedback from MSD. Table 1 identifies the weighting applied to each benefit category and briefly describes the approach to score the BMPs. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 6 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table 1. Approach for Scoring and Weighting Benefits. Benefit Group Benefit Category Weighting Scoring Approach Target Pollutant Benefits E. Coli Treatment 30% First, benefits from pollutant concentration reductions will be calculated based on median effluent concentrations from the International Stormwater BMP database5, along with statistical results showing whether the removal was significant (e.g. non-parametric hypothesis tests, either the Mann-Whitney rank sum test or the Wilcoxon signed-rank test). Then these scores will be modified to include the pollutant reductions resulting from volume reduction. Nitrite (NO2) and Nitrate (NO3) Nitrogen Treatment 15% Total Phosphorus Treatment 15% Additional Benefits Other Water Quality Parameter Treatment 15% Based on significant reduction of other important water quality parameters (e.g., total suspended solids, metals, chloride) as reported in the Boston BMP Guidance Document6. Flood Management 10% The relative ability to decrease flood risk by reducing peak flow rates and/or volume reduction based on the Boston BMP Guidance Document. Habitat/ Environmental Improvements 7% Improvement and protection of wetland and riparian enhancement/ creation evaluated by best professional judgment. Community Enhancements 8% Based on three factors: (1) Enhancement/creation of recreational and public use areas, (2) Educational opportunities, or (3) Aesthetic benefits evaluated by best professional judgment. Since the focus of this memorandum is evaluating BMP selection based on water quality performance for bacteria and nutrients, benefits associated with the treatment of those target pollutants were grouped and assigned the highest weighting factor. Because there are TMDLs already in effect for bacteria in the St. Louis area, the E. coli weighting factor was higher than the nutrients factor. The scoring of target pollutant benefits was performed quantitatively based on the measured inflow and outflow concentrations for all BMPs that met data quality and 5 Geosyntec Consultants, Inc., Wright Water Engineers, Inc., International Stormwater BMP Database, Manufactured Devices Performance Summary Report. July 2012. and International Stormwater Best Management Practices (BMP) Database Pollutant Category Statistical Summary Report Solids, Bacteria, Nutrients, and Metals http://www.bmpdatabase.org/ 6 Boston Water and Sewer Commission, Stormwater Best Management Practices: Guidance Document, prepared by Geosyntec Consultants. January 2013. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 7 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo quantity criteria7 from the International Stormwater BMP Database5. The scoring guidance for the target pollutants is defined in Table 2. The analysis of the target pollutant benefits and the benefit score for each post-construction structural BMP/Target Pollutant combination8 is reported in Table A-1. Table 2. Target Pollutant Benefit Scoring Guidance for Water Quality Benefits for BMPs. Score Target Pollutant Benefit 3 High pollutant removal 2 Medium pollutant removal 1 Low or no pollutant removal In addition to treating stormwater for the target pollutants, the BMPs were evaluated for other benefits (Table A-2). These other benefits included: 1) reduction of other important water quality parameters (e.g., TSS/sediments and metals), 2) ability to decrease flood risk by reducing peak flow rates and/or volume reduction, 3) improvement and protection of wetland and riparian enhancement/creation, and 4) community enhancements and opportunities. The weighting factors for these additional benefits reflect their relative significance to MSD, while still recognizing the important benefits that they could provide. The scoring of the additional benefits was performed qualitatively based on the Boston BMP Guidance Document and best professional judgment as defined in Table 3. The analysis of the additional benefits and the benefit score for each BMP/additional benefit combination is reported in Table A-2. 7 To be included in this category-level summary, at least three BMP studies must be included in the BMP category, with each BMP study having influent and effluent data for at least three storms for the pollutant of interest. 8 Post-construction ordinances and advanced structural BMPs do not have reported effluent concentrations in the International Stormwater BMP database and therefore were not included in the Table A-1 analysis. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 8 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table 3. Scoring Guidance for Additional Benefits of BMPs. Score Other Water Qualitya Flood Management Habitat/ Environmental Communityb 3 High in both sediment and metals reduction High volume and peak flow reduction Significant portion of BMP creates habitat BMP provides high potential for all two to three community benefits 2 Medium sediment and metals reduction Medium volume and peak flow reduction Some portion of BMP creates habitat BMP provides medium potential for two community benefits 1 Low or no sediment and metals reduction Low or no volume and peak flow reduction Small amount or no of habitat created BMP provides low or no potential for two community benefits a. Chloride was also considered for evaluation in the “Other Water Quality” category; however, only limited performance data exists for chloride and little or negative removal is shown for those BMPs with data. Therefore, chloride was excluded in the scoring. b. Community benefits include enhancement/creation of public use areas; educational opportunities; and community aesthetics. Scores for each benefit category, as described above, were multiplied by their weighting factors (Table 1) and a combined benefit score for each BMP9 was calculated and reported in Table A-3. The BMPs were then ranked according to their scores and the results are summarized in Table 4. 9 This table also includes scores for target pollutant benefits for post-construction ordinances and advanced structural BMPs based on expected performance relative to similar BMP types determined using best professional judgment. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 9 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table 4. Distribution of BMPs Used within the MSD Service Area and Benefits Ranking. Rank BMP Score % of BMPs Built or Planned 1 Infiltration BMPs 2.9 1% 2 Subsurface Flow Wetlands 2.8 NA 3 Ponds 2.6 1% 4 Enhanced Biofilters 2.5 NA 5 Bioretention 2.4 48% 5 Permeable Pavement 2.0 18% 7 Surface Sand Filters 1.8 0.04 8 Underground Sand Filters 1.8 1% 9 Underground Manufactured Filters 1.5 0.01 10 HDS Units 1.5 6% 11 Cisterns 1.4 0.01 12 Impervious Area Reduction 1.4 NA 13 Engineered Swales 1.3 4% 14 Tree Preservation Ordinance 1.2 NA 14 Stream Buffer 1.2 NA Relative Cost Rankings for Structural BMPs To provide estimates of the local capital and annual maintenance costs of the post-construction structural BMPs and evaluate the relative cost ranking for the post-construction structural BMPs and ordinances and advanced structural BMPs, the following cost analysis was conducted. The cost estimations presented in this section are based on estimates of probable capital and maintenance costs per capture (treatment) of runoff from one acre of drainage area. The costs were computed by developing a cost estimation procedure that uses unit cost information from literature for capital and maintenance costs to create curves (cost per volume treated translated into cost per tributary area treated) for stormwater BMPs. Example unit cost items include: • Mobilization • Demolition • Clearing & Grubbing • Dewatering • Excavation • Haul/Dispose of Excavation Material Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 10 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo • Rough and Finished Grading • Pipe Material (primarily underdrain) • Soil Media / Planting Media • Other Bulk Material (pea gravel, clean-washed gravel, base course gravel and bedding material) • Pavement/Concrete/Curbs • Mulch • Vegetation Because there are many factors that affect the capital costs of structural BMPs besides the treatment volume, such as development type (new development, redevelopment, retrofit), native soil infiltration rate, site slope, pretreatment requirements, existing infrastructure, and large event/overflow safety, a range of costs is included as part of the cost estimation. While the costs for the effort were calculated on a national scale using literature and bid tabs from across the country, an approach was developed using Bureau of Labor Statistics data for stormwater construction equipment, material and labor to tailor estimated costs to the St. Louis region. Other factors that can often influence costs such as: land acquisition, project purpose (e.g., demonstration project), regulatory and permitting requirements, utility conflict resolution, design, union/non-union rates, and level of experience of designers and contractors were not included as a part of the cost estimation. The three-step cost estimation approach is briefly summarized below as follows: • Step 1: Size BMPs – assume a 1-acre drainage area and use the 1.14-inch design storm for the study area to compute the design volume of runoff required for each BMP for a 1- acre residential (typically low estimate because of lower impervious surface density) and 1-acre commercial lot (typically higher estimate because of greater impervious surface density requiring a larger treatment volume and therefor larger treatment facility). • Step 2: Apply Cost Curve –determine cost curves function for each scenario and obtain low/high cost estimation range for BMPs to meet design requirements. Report cost estimate as a range comprised of the low residential estimate (assumed to be 35% site imperviousness) and the high commercial estimate (assumed to be 65% site imperviousness) to effectively bracket costs. Of note, if impervious density is greater, than a higher cost would be needed to capture and treat the associated design volume. • Step 3: Apply Cost Regionalization and Inflation Adjustment – Convert national itemized unit cost estimates from RS Means, built projects, bid tabs, and other data sources, using stormwater construction specific regional cost adjustment factor based on Bureau of Labor Statistics data for St. Louis from Step 1. An inflation adjustment factor was applied as needed to obtain 2015 estimates (the most recent complete year for Bureau of Labor Statistics data). The result of applying the three-step cost estimation approach is shown in Table 5. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 11 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table 5 Estimates of Probable BMP Construction and Maintenance Costs per Acre of Drainage Area Treated. Post-Construction BMPS Initial Capital Cost Estimate Range* (Treatment for a 1-acre site) Annual Maintenance Cost Estimate Range (Per System) Low High Low High Bioretention $ 10,800 $ 25,400 $ 900 $ 4,000 Infiltration BMPs $ 4,800 $ 29,000 $ 700 $ 4,400 Engineered Swales $ 3,500 $ 17,600 $ 200 $ 1,300 Permeable Pavement $ 8,200 $ 27,600 $ 800 $ 3,100 Cisterns $ 12,400 $ 21,600 $ 200 $ 700 Ponds $ 9,000 $ 30,800 $ 700 $ 4,900 Surface Sand Filters $ 14,400 $ 38,800 $ 900 $ 3,200 Underground Sand Filters $ 17,000 $ 50,200 $ 1000 $ 3,700 Underground Manufactured Filters $ 12,200 $ 39,300 $ 1,100 $ 4,600 HDS Units $ 14,100 $ 42,200 $ 1,000 $ 3,700 *Cost curves are not on a per acre basis as many costs are necessary for the first unit of BMP. Subsequent/additional costs may not be linear and may not have a one to one relationship with area. Approximate volume of treatment for the 1-acre site was about 1,450-2,700 ft3. Sizing for cost estimation is based on an assumed volumetric capture (about one inch) but does not include achieving a required level of performance. To rank the structural BMPs, the average capital and maintenance costs were computed and BMPs were ranked and placed into tiers representing similar costs between BMPs. The relative capital cost and maintenance scores for each BMP were assessed for an estimated 20-year life cycle cost to capture the long-term maintenance cost estimates along with initial capital costs. The BMPs were then ranked according to their scores. The results are summarized in Table 6. A lack of data on post-construction ordinances and the advanced structural BMPs resulted in these management strategies receiving no cost score to prevent comparison and potential biases between BMPs of known and unknown costs. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 12 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table 6 Rankings Based on Estimates of Probable Capital and Maintenance Costs Tier BMP Estimated Cost Score 1 Engineered Swales 3.0 Cisterns 2.5 Bioretention 2.4 Infiltration BMPs 2.4 Ponds 2.3 Permeable Pavement 2.2 2 Underground Manufactured Filters 1.6 Surface Sand Filters 1.6 HDS Units 1.4 Underground Sand Filters 1.0 3 Stream Buffer NA Tree Preservation Ordinance NA Impervious Area Reduction NA Enhanced Biofilters NA Subsurface Flow Wetlands NA Not applicable (NA) was assigned to BMPs that did not have available cost information. Site-Specific Considerations for Using Structural BMP Rankings An important component of post-construction runoff control programs, relative to the iterative process of removing pollutants to the MEP, is the process for accounting for site-specific feasibility issues and constraints. This issue is typically addressed in BMP technical guidance manuals for new and redevelopment (and possibly in stormwater ordinances as well), and each MS4 permittee or jurisdiction may choose to exercise their authority and level of prescriptiveness differently. As one example, the Orange County Technical Guidance Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 13 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Document10 establishes detailed infeasibility criteria for each BMP type. Below are some very basic infeasibility criteria examples and their implications for BMP suitability relative to the BMP ranking established herein: • Infiltration constraints (e.g., tight soils and shallow bedrock or groundwater that would prohibit infiltration based options) – At sites where such constraints exist, ponds, subsurface flow wetlands, and enhanced biofilters are treatment-only BMPs that are acceptable alternatives based on demonstrated pollutant removal performance. • Limited space for BMP footprint (e.g., steep slopes within the site) – In this case, permeable pavement is an acceptable and effective option to retain/treat stormwater where the BMP area is incorporated into the development footprint. Also, enhanced biofilters typically have a larger treatment capacity (i.e., can be built smaller, while still treating the same design flowrate or volume) than similarly sized, higher ranked BMPs. • Large design volumes requiring treatment (e.g., significant impervious area within the site) – This constraint could make some BMP types infeasible unless implemented in combination with others (e.g., large cisterns may be impractical). In general, project applicants should be encouraged to consider the benefits of BMP combinations (e.g., treatment trains, distributed BMPs), where appropriate. Finally, and related to both MEP and necessary components of any BMP technical guidance manual, since this BMP ranking evaluation assumed all BMP types are sized the same, clear design storm guidance should accompany any BMP selection guidance that is provided to project applicants. NON-STRUCTURAL BACTERIA AND NUTRIENT BMP EVALUATION To better understand the extent to which non-structural BMPs are currently being implemented to target bacteria and nutrients, stormwater program managers from MSD and seven other MS4 communities were surveyed. These communities were selected based on their geographic distribution and ease of obtaining information. Furthermore, although MSD is a Phase II MS4, both Phase I and II communities were included in the survey. Both Phase I (large) and II (small) systems were surveyed since MSD’s stormwater system is more comparable in size to Phase I communities; however, it is controlled under Phase II regulations and permit requirements. The number of MS4 communities surveyed in each EPA region included: 10 County of Orange, 2013. Technical Guidance Document (TGD) for the Preparation of Conceptual/Preliminary and/or Project Water Quality Management Plans (WQMPs). December 20, 2013. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 14 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo • MSD (EPA Region 7 – Phase II Community) • EPA Region 7 – Phase I Community (2) • EPA Region 7 – Phase II Community (1) • EPA Region 4 – Phase I Community (1) • EPA Region 4 – Phase II Community (1) • EPA Region 5 – Phase II Community (2) Program managers were presented with a list of potential bacteria and nutrient BMPs that could be implemented under each of the six MCMs required by Phase II MS4 regulations. These BMPs were developed from suggestions presented in the literature11 and best professional judgment (see Table A-5 for the list of BMPs). Program managers were asked to identify BMPs from the list that are currently being applied within their system. It should be noted that the list of BMPs was not intended to be all-encompassing. Rather, it reflects those BMPs most commonly considered to be effective for managing bacteria and nutrients For those BMPs being applied, the managers were then asked to qualitatively assess the degree to which each is implemented using the following categories: • High (green) – BMP is used with active management, measurement, or tracking. • Medium (yellow) – BMP implemented but with limited measurement or tracking measurement. • Low (red) – BMP implemented intermittently but few to no measurements or tracking. • None (blank) – BMP unused or unknown. To assist in making meaningful comparisons between the qualitative assessment results, each community response was converted to a relative score (high = 3, medium = 2, low = 1, none = 0). Converted response scores were then summed and standardized for each BMP category to develop a normalized implementation score that ranges from 0 to 1. The normalized implementation scores serve to represent the degree to which each BMP is implemented across the surveyed communities. For a given BMP category, values near 0 indicate that few of the surveyed communities use the BMP with limited implementation; values near 1 indicate that most surveyed communities use the BMP with active implementation. For this evaluation, normalized community scores were interpreted using the following scale: 11 Urban Water Resources Research Council (UWRRC). 2014. Pathogens in Urban Stormwater Systems. Environmental and Water Resources Institute. American Society of Civil Engineers. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 15 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo • Less than or equal to 0.4 – Limited implementation. The BMP may not be applicable to or appropriate for many communities. MSD should generally consider them to be low priority BMPs. • Between 0.4 and 0.6 – Moderate implementation. The BMP is commonly used and should be considered for MSD’s program, if applicable. • Greater than 0.6 – High implementation. The BMP is commonly used in most communities. MSD should generally consider these to be high priority BMPs and identify opportunities to include within the stormwater program. Results of the evaluation show that the implementation of non-structural bacteria and nutrient BMPs varies between MCMs and across the surveyed communities (Figure 2). In general, BMPs under MCMs #1 (public education and outreach) and #6 (pollution prevention and good housekeeping) have limited implementation, with several BMPs scoring between 0 and 0.4 for all of the communities. The primary exceptions to this limited implementation are pet waste and fertilizer outreach programs under MCM #1. In contrast, many BMPs under MCMs #3 (illicit discharge detection and elimination) and #5 (post-construction stormwater management) have scores between 0.6 and 1, indicating that these BMPs are generally implemented actively by all of the communities. Results from MCM #2 (public involvement and participation) suggest that most BMPs are consistently but moderately implemented by the communities (scores of 0.4 to 0.6). The community survey scores were compared to those from MSD’s program to evaluate the District’s current progress relative to other established programs and identify potential areas for future enhancement. An overview of results for MSD’s stormwater program relative to the surveyed communities for each MCM is included below. An overview of results for MSD’s program relative to the surveyed communities for each MCM is included below. • MCM #1 – Public Education and Outreach: Most BMPs are implemented to a limited degree (score of less than 0.4) across the surveyed communities. Similarly, MSD does not use many of the BMPs that were reviewed. With the exception of fertilizer outreach efforts, BMPs that MSD does apply are implemented more actively relative to the other MS4s. • MCM #2 – Public Involvement and Participation: With the exception of downspout disconnection and site designs (BMP 2.7), BMPs under this MCM are at least moderately implemented across the communities. MSD implements most of the BMPs to a comparable or greater degree than the other communities. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 16 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo • MCM #3 – Illicit Discharge Detection and Elimination: In general, these BMPs are highly implemented across the communities. MSD implements a majority of BMPs under this MCM to a comparable or greater degree than the other communities. • MCM #4 – Construction Site Stormwater Runoff Control: MSD’s implementation of the two BMPs reviewed under this MCM are generally comparable to the other communities. • MCM #5 – Post-Construction Stormwater Management: BMPs under this MCM are actively implemented across the communities. MSD implements a majority of BMPs to a comparable or greater degree than the other communities. • MCM #6 – Pollution Prevention and Good Housekeeping: Implementation of BMPs under this MCM was mixed across the surveyed communities. The BMPs that MSD does apply are generally implemented more actively relative to the other communities. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 17 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Figure 2. Summary of Non-Structural Bacteria and Nutrient BMP MS4 Community Survey Results. Normalized implementation scores were calculated based on the degree to which each BMP is implemented across the surveyed communities. For a given result, values near 0 indicate that few communities use the BMP with limited implementation; values near 1 indicate that most communities use the BMP with extensive implementation. For BMP identification numbers, refer to the community survey results in Table A-5. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 18 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo As MSD investigates enhancements to their stormwater programs over time, program managers should initially focus on evaluating high priority (scores greater than 0.6) BMPs from the community survey that are either not widely used or currently have limited implementation in the St. Louis area. These include a using a public reporting tool (BMP 3.6), improving existing septic system inventory activities (BMP 3.8), and increasing street sweeping frequency (BMP 6.8). Once high priority BMPs have been addressed, MSD should review the moderately-implemented (scores of 0.4 – 0.6) community survey BMPs to determine if they can be used or improved. These BMPs include: • Conducting private fertilizer education programs (BMP 1.3), • Creating a tree sale program (BMP 2.2), • Increasing the number and accessibility of public trash cans and pet waste stations (BMP 2.6), • Improving baseflow source identification practices (BMP 3.1), • Conducting instream algae monitoring (BMP 3.10), • Improving construction site runoff control procedures on small sites (BMP 4.2), and • Establishing a septic system elimination program (BMP 3.9). MSD has recently worked to eliminate some septic systems in the St. Louis City and County area as part of their Sewer Connection and Septic Tank Closure Program. Funding for this program included a one-time allocation of approximately $2 million from MSD’s Project Clear. MSD and their co-permittees should review the efficacy of the recent elimination program and determine its viability as a permanent BMP going forward. BMPs identified as having limited implementation in the community survey should be considered a low priority for potential incorporation into MSD’s stormwater management program. These BMPs should be reviewed over time as resources permit. Other Considerations that Affect MEP for Non-Structural BMPs While it is useful to understand MCM implementation by other MS4 communities across the country to help establish what MEP is, MEP is also established in part by standard guidance. For example, in ASCE’s Pathogens in Urban Stormwater Systems12 report and presentations, it is 12 Urban Water Resources Research Council (UWRRC). 2014. Pathogens in Urban Stormwater Systems. Environmental and Water Resources Institute. American Society of Civil Engineers. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 19 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo noted that non-structural BMP selection should be agency-specific (and thus not be designed to precisely match the actions of other communities) and based on local sources. Local sources of nutrients and bacteria should first be identified based on existing available GIS and monitoring data, local knowledge and observations, and special studies. Then sources should be prioritized based on risk level (e.g., human waste presents a greater illness risk than non-human and non- fecal bacteria, certain forms of nutrients are more bioavailable or controlling in the eutrophication process), and controllability. Once local sources are prioritized, then non- structural source control BMPs should be selected to specifically target the highest priority sources. This process, as documented through nationwide guidance, further helps to establish the MEP. An example process for bacteria is described here. Bacteria sources are typically ubiquitous in the urban environment and numerous sources could contribute to excessive levels in urban waterbodies. Therefore, a list of general urban sources and identification of non-structural BMPs to address these typical sources would likely be too broad to develop a tailored non-structural BMP program for each subwatershed or MS4 community. Guidance for identifying subwatershed or MS4 community-specific bacteria sources can be found in the ASCE publication, Pathogens in Urban Stormwater Systems, including: • GIS mapping and analysis of infrastructure and analysis of monitoring data to identify potential problem areas; • Meeting with field staff and others with experience in the subwatershed to compile their local knowledge; • Subwatershed-specific observations; • Enhanced illicit discharge detection and elimination (IDDE) investigations of MS4, including microbial source tracking and traditional tools (e.g., CCTV and dye testing). This source inventory could then be categorized and prioritized based on controllability and public health risk, with human, non-human, and non-anthropogenic sources representing high, medium, and low risk categories, respectively. Then non-structural BMPs could be selected to effectively target the high and medium risk categories as comprehensively as possible and as available funding allows. The ASCE pathogen publication provides examples of cost-effective potential BMPs that may be considered based on the source identification findings, including: • Sewer repairs where enhanced IDDE investigations have shown wastewater collection systems leaking into the MS4 • Education/outreach to residential homeowners on limiting fertilizer application • Improved prevention/housekeeping practices to limit fertilizer use by municipal operations • Pet waste disposal ordinances in areas of high pet density. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 20 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Ultimately it may be more effective to aggressively implement a fewer number of BMPs that are targeted to highest priority sources than to attempt to match the level of BMP implementation of most other MS4 communities. For example, while resource intensive, septic inspection/inventory and illicit connection detection are two of the most important BMPs for controlling human waste and pathogens. MSD is implementing these BMPs at a “medium” or lower level. With increased resources, efforts could be focused in high priority areas to better match the state of the practice as documented in available nationwide guidance. SUMMARY AND NEXT STEPS Several new state regulatory requirements will impact how MSD administers their stormwater management program. These new requirements will require MSD to evaluate and identify BMPs that reduce bacteria and nutrients in stormwater runoff to the MEP. To assist MSD in characterizing MEP for bacteria and nutrient, MSD’s existing structural and non-structural BMPs were evaluated relative to the state of the practice and other MS4 programs. Significant findings from this evaluation include the following: • The top ranked structural BMPs (with a combined cost and benefit score above 4, as shown in Table 7) were those that reduce runoff volume through infiltration or capture or had advanced flow through designs. Few flow-through structural BMPs have effluent concentrations that consistently meet water quality criteria for bacteria and nutrients (only ponds). • Approximately 70% of the built or planned structural BMPs in the MSD MS4 area are ranked in the top three for benefits and have average scores (approximately 2) for costs. • Post-construction ordinances and very basic structural BMPs were top ranked based on costs, however these BMPs provided only minimal benefits. • The treatment structural BMPs that incorporate advanced design characteristics (e.g., subsurface flow wetlands and enhanced biofilters) provide top ranked benefits, however, their poor costs rankings can be prohibitive for some implementation scenarios. • Site-specific feasibility issues and constraints can dramatically affect the performance and costs of BMP types and should be considered early in the planning process. • Going forward, MSD should focus on evaluating high priority (scores of greater than 0.6) BMPs from the community survey that are either not widely used or currently have limited implementation in the St. Louis area. Once high priority BMPs have been addressed, MSD should review the moderately-implemented (scores between 0.4 and 0.6) community survey BMPs to determine if they can be used or improved. Community survey BMPs with limited implementation (scores less than 0.4) should be reviewed as resources become available. Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 21 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo • A comprehensive source identification and prioritization process directing the implementation of non-structural BMPs can dramatically affect the effectiveness and efficiency of the program. Table 7 Benefits and Estimates of Probable Capital and Maintenance Costs BMP Estimated Benefits Score (Out of 3) Estimated Cost Score (Out of 3) Infiltration BMPs 2.9 2.4 Subsurface Flow Wetlands 2.8 NA Ponds 2.6 2.3 Enhanced Biofilters 2.5 NA Bioretention 2.4 2.4 Permeable Pavement 2.0 2.2 Surface Sand Filters 1.8 1.6 Underground Sand Filters 1.8 1 Underground Manufactured Filters 1.5 1.6 HDS Units 1.5 1.4 Cisterns 1.4 2.5 Impervious Area Reduction 1.4 NA Engineered Swales 1.3 3.0 Stream Buffer 1.2 NA Tree Preservation Ordinance 1.2 NA Not applicable (NA) was assigned to BMPs that did not have available cost information. Results of this evaluation can be used to help review the MSD BMP Toolbox (http://www.stlmsd.com/what-we-do/stormwater-management/bmp-toolbox) and identify potential areas to enhance BMP implementation. Some preliminary examples include: • Highlighting the importance of implementing BMPs that focus on bacteria and nutrient reduction. • Providing guidance for the selection of BMPs capable of achieving bacteria and nutrient reduction given site-specific conditions (e.g., land use, space constraints, rainfall patterns, Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 22 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo etc.) or identified sources (e.g., residential and municipal over-fertilization, dumpsters, washdown and grease traps at food outlets). • Providing additional BMP design guidance related specifically to bacteria and nutrient removal including: o Vegetation selection o Outlet controls/contact time guidance o Media selection and specification o Removal of compost/alternative soil amendments (a source of nutrients) o Incorporation of saturated zone for bacteria and/or nitrogen removal o Incorporation of an activated alumina layer for phosphorus removal o Other pertinent design information based on findings from literature ***** Bacteria and Nutrient BMP Strategy Review December 23, 2016 Page 23 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo ATTACHMENT A BMP EVALUATION RESULTS MSD Structural BMP Evaluation December 23, 2016 Page 24 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table A-1. Benefit Scores for Each Structural Best Management Practice (BMP)/Target Pollutant Combination E. Coli Treatment Nitrite (NO2) + Nitrate (NO3) as Nitrogen Treatmentd Total Phosphorus Treatment Post-Construction Structural BMPs BMP Database Category Median Effluent Concentration (colonies /100ml) Statistically Significant Removal (Y/N) Score Median Effluent Concentration Statistically Significant Removal (Y/N) Score Median Effluent Concentration Statistically Significant Removal (Y/N) Score (mg/L) (mg/L) Bioretention Bioretention 101 Y 3 0.37 N 1 0.24 N 1 Infiltration BMPs Not Available Not Available 3 Not Available 3 Not Available 3 Engineered Swales Biofilter - Grass Swale 4,182 N 1 0.22 N 1 0.171 N 1 Permeable Pavement Porous Pavement Not Available 3 1.35 N 3 0.1 Y 3 Cisterns Not Available Not Available 1 Not Available 1 Not Available 1 Ponds Retention Pond 100 Y 3 0.13 Y 2 0.091 Y 2 Surface Sand Filters Media Filter 420a Y 2 0.57 N 1 0.089 Y 2 Underground Sand Filters Media Filter 420a Y 2 0.57 N 1 0.089 Y 2 Underground Manufactured Filters Manufactured Device - Filtration 910b N 1 0.29c N 1 0.06 Y 2 HDS Units Manufactured Device - Physical 910b N 1 0.36c Y 2 0.22 Y 2 a. The International Stormwater BMP Database does not have sufficient data for Media Filter E. coli effluent concentrations; therefore, the reported fecal coliform was evaluated. b. The BMP Database does not have sufficient data for Manufactured Devices (Filtration and Physical) E. coli effluent concentrations; therefore, the reported fecal coliform was evaluated. c. The BMP Database does not have sufficient data for Manufactured Devices (Filtration and Physical) NO2 + NO3 as Nitrogen effluent concentrations; therefore, NOx as Nitrogen was evaluated. d. NO2 + NO3 as Nitrogen was evaluated since it had the most results in the BMP Database. MSD Structural BMP Evaluation December 23, 2016 Page 25 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table A-2. Additional Benefit Scores for Each BMP/Targeted Benefit Combination Other Water Quality Treatment Flood Management Habitat / Environmental Community Enhancements Post-Construction Structural BMPs Sediment Reduction Metals Reduction Score Volume Reductiona Peak Flow Reduction Score Habitat Creation Score Enhancement/ Creation of Public Use Areas Educational Opportunities Community Aesthetics Score Bioretention High High 3.0 High Medium 2.5 High 3.0 High High High 3.0 Infiltration BMPs High High 3.0 High High 3.0 Medium 2.0 Medium High Medium 2.3 Engineered Swales Medium Medium 2.0 Low Low 1.0 Medium 2.0 Medium Medium Medium 2.0 Permeable Pavement Medium Medium 2.0 Medium Medium 2.0 Low 1.0 Low Medium Low 1.3 Cisterns High Medium 2.5 High Medium 2.5 Low 1.0 Low Medium Medium 1.7 Ponds High High 3.0 Low High 2.0 High 3.0 High High High 3.0 Surface Sand Filters High High 3.0 Low Low 1.0 Low 1.0 Low Medium Low 1.3 Underground Sand Filters High High 3.0 Low Low 1.0 Low 1.0 Low Low Low 1.0 Underground Manufactured Filters High High 3.0 Low Low 1.0 Low 1.0 Low Low Low 1.0 HDS Units Medium Medium 2.0 Low Low 1.0 Low 1.0 Low Low Low 1.0 Post-Construction Ordinances Stream Buffer Medium Medium 2.0 Low Medium 1.5 High 3.0 High Medium High 2.7 Tree Preservation Ordinance Low Low 1.0 Medium Low 1.5 High 3.0 High Medium High 2.7 Impervious Area Reduction Medium Medium 2.0 Medium Medium 2.0 Medium 2.0 High Low Medium 2.0 Advanced Structural BMPs Enhanced Biofilters (e.g., Bioretention with underdrains) High High 3.0 Medium Medium 2.0 High 3.0 Medium High High 2.7 Subsurface Flow Wetlands High High 3.0 Medium Medium 2.0 High 3.0 High High High 3.0 a. It is assumed that all the BMPs are sized to treat the same design storm (e.g., bypass from a flow through BMP such as engineered swales, sand filter, pond, etc. would be as frequent as from a retention BMP such as bioretention, infiltration basin, etc.). For this reason, both bioretention and cisterns are assumed to have high volume reduction. MSD Structural BMP Evaluation December 23, 2016 Page 26 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table A-3. Summary of Structural BMP/Benefit Scoring Target Pollutant Benefitsa Additional Benefits E. Coli Total Nitrogen Total Phosphorus Other Water Quality Flood Management Habitat/ Environmental Community Enhancements Total Score Rank (out of 15) Weighting 30% 15% 15% 15% 10% 7% 8% 100% Post-Construction Structural BMPsb % of BMPs Built or Planned 1-3 1-3 1-3 1-3 1-3 1-3 1-3 3 Bioretention 48% 3.0 1.0 1.0 3.0 2.5 3.0 3.0 2.4 5 Infiltration BMPs 1% 3.0 3.0 3.0 3.0 3.0 2.0 2.3 2.9 1 Engineered Swales 4% 1.0 1.0 1.0 2.0 1.0 2.0 2.0 1.3 13 Permeable Pavement 18% 3.0 1.0 2.0 2.0 2.0 1.0 1.3 2.0 6 Cisterns 1% 1.0 1.0 1.0 2.5 2.5 1.0 1.7 1.4 11 Ponds 1% 3.0 2.0 2.0 3.0 2.0 3.0 3.0 2.6 3 Surface Sand Filters 4% 2.0 1.0 2.0 3.0 1.0 1.0 1.3 1.8 7 Underground Sand Filters 1% 2.0 1.0 2.0 3.0 1.0 1.0 1.0 1.8 8 Underground Manufactured Filters 1% 1.0 1.0 2.0 3.0 1.0 1.0 1.0 1.5 9 HDS Units 6% 1.0 2.0 2.0 2.0 1.0 1.0 1.0 1.5 9 Total systems install on new or redevelopment since 2006 4,516 Post-Construction Ordinances Stream Buffer NA 1.0 1.0 1.0 2.0 1.0 3.0 3.0 1.2 15 Tree Preservation Ordinance NA 1.0 1.0 1.0 1.0 1.0 3.0 2.0 1.2 14 Impervious Area Reduction NA 1.0 1.0 1.0 2.0 2.0 2.0 2.0 1.4 12 Advanced Structural BMPs Enhanced Biofilters NA 3.0 1.0 3.0 3.0 1.0 3.0 3.0 2.5 4 Subsurface Flow Wetlands NA 3.0 3.0 3.0 3.0 1.0 3.0 3.0 2.8 2 a. BMPs with high volume reduction (see the Flood Management category in Table A-2) have a target pollutant benefit of 5. For BMPs with medium volume reduction have 1 point added to each target pollutant effluent concentration score b. The permitted structural BMP "storm credits" and "other" are not included in the BMP scoring because of the variety of approaches used in each of those categories MSD Structural BMP Evaluation December 23, 2016 Page 27 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table A-4. Summary of Structural BMP/Cost Scoring Initial Capital Cost Estimate Rangea Annual Maintenance Cost Estimate Range Averaged Score (out of 3) Rank (out of 10) (Treatment for a 1-acre site) (Per System) Post-Construction Structural Controls Low High Average Low High Average Bioretention $7,800 $25,400 $16,600 $4,000 $2,450 $19,050 2.4 3 Infiltration BMPs $4,800 $29,000 $16,900 $4,400 $2,550 $19,450 2.4 4 Engineered Swales $3,500 $18,700 $11,100 $1,300 $750 $11,850 3.0 1 Permeable Pavement $8,200 $27,600 $17,900 $3,100 $1,950 $19,850 2.3 5 Cisterns $12,400 $21,600 $17,000 $800 $500 $17,500 2.5 2 Ponds $9,000 $26,900 $17,950 $4,500 $2,600 $20,550 2.3 6 Surface Sand Filters $14,400 $38,800 $26,600 $3,200 $2,050 $28,650 1.6 8 Underground Sand Filters $16,200 $50,200 $33,200 $3,700 $2,350 $35,550 1.0 10 Underground Manufactured Filters $12,200 $39,300 $25,750 $4,600 $2,850 $28,600 1.6 7 HDS Units $14,100 $42,200 $28,150 $3,700 $2,350 $30,500 1.4 9 Post-Construction Ordinancesb Stream Buffer NA NA Tree Preservation Ordinance NA NA Impervious Area Reduction NA NA Advanced Structural Controlsb Enhanced Biofilters NA NA Subsurface Flow Wetlands NA NA a. Cost curves are not on a per acre basis as many costs are necessary for the first unit of BMP. Subsequent/additional costs may not be linear and may not have a one to one relationship with area. Approximate volume of treatment for the 1-acre site was about 1450-2700 ft3. Sizing for cost estimation does not include achieving a required level of performance. b. Cost estimates were not available for post-construction ordinances or advanced structural BMPs, therefore relative costs were assigned using best professional judgment. MSD Structural BMP Evaluation December 23, 2016 Page 28 MOW5165E | St. Louis | 2016(1223)_MSD_BMP_Evaluation_Memo Table A-5. Non-Structural Bacteria and Nutrient Best Management Practice (BMP) MS4 Community Survey Results.