Ft_Jackson_TMDL_Implementation_Plan_12.27.17.pdf

Woolpert Inc.

December 2017 Fort Jackson Environmental Division 1

TMDL Implementation Plan Fort Jackson Environmental Division

December 2017

1 Introduction The Fort Jackson Environmental Division (ENV) has implemented a progressive water quality monitoring program designed to assess the water quality conditions draining Fort Jackson’s cantonment area and to ensure compliance with ENV’s Phase II National Pollutant Discharge and Elimination System (NPDES) permit for its Municipal Separate Storm Sewer System (MS4). ENV’s continuous monitoring data is supplemented by a bacteria grab sample collection program. In accordance with the ENV’s Phase II NPDES permit, the report contained herein provides a description of the ENV monitoring program, including relevant background information and an explanation of program methods, a summary and assessment of the continuous water quality data collected from January 2015 – June 2017, and a prioritization, description, and schedule for implementing Best Management Practices (BMPs) to achieve progress towards addressing the Total Maximum Daily Load’s (TMDLs) wasteload allocation (WLA).

1.1 Background

On January 1st, 2014, the new Phase II NPDES permit issued by the South Carolina Department of Health and Environmental Control (SCDHEC) (Permit No. SCR030000) went into effect. Fort Jackson, as a Phase II permittee, is required to comply with this permit, which includes provisions to create and implement a monitoring plan to assess water quality from the MS4 if located within a TMDL watershed. In 2009, fecal coliform and dissolved oxygen (DO) TMDL requirements were established for the Gills Creek Watershed, thereby requiring the Fort to monitor the water quality of representative MS4 discharges to the water body. Following a period of water quality data collection, the Fort’s permit requires a TMDL Implementation Plan to be submitted by January 1, 2018. This document provides an assessment of the collected monitoring data that discusses any trends observed in the data and plans to implement BMPs to address the DO and fecal coliform TMDLs.

ENV has conducted various water quality monitoring studies in compliance with both its current NPDES permit and its previous NPDES permit. These efforts initially were targeted at assessing water quality impacts of construction activities associated with the ENV MS4 permit. These sampling efforts used a variety of sampling methods such as grab sampling, targeted monitoring of construction activities, and in-situ continuous monitoring. Following the publication of the Gills Creek Watershed DO and fecal coliform TMDLs, ENV focused its monitoring program on a continuous ambient water quality monitoring approach for tributaries draining to the Gills Creek Watershed.

In January 2015, ENV installed a permanent water quality monitoring station in its current location, referred to as “ENV5,” an acronym assigned to this location during the initial sampling site inventory process. The ENV5 station is located on Wildcat Creek, within the boundary of Fort Jackson, providing ENV with access to the monitoring site and draining approximately 40% of the urbanized area within Fort Jackson that is in the Gills Creek TMDL watershed. The ENV5 location has been recording data since January, 2015, and provides a good representation of the water quality of Wildcat Creek as it exits the Fort’s jurisdiction.

1.2 Continuous Water Quality Monitoring

For the past several stages of its monitoring program, ENV has elected to collect high frequency, continuous data, coupled with grab sample data, rather than solely relying on periodic grab sample data to assess water quality. In a continuous monitoring approach, sensors are deployed in a waterbody for extended periods of time, generally 4 to 6 weeks. During these deployments, water quality parameters are sampled at high frequencies, in the case of ENV’s program, at 15-minute increments. Continuous data collection has enabled ENV to observe parameter concentration fluctuations in greater detail, after working hours, and during inclement weather—conditions that would be difficult

December 2017 Fort Jackson Environmental Division 2 to characterize through manual grab sample analysis alone. Additionally, ENV maintains a remote telemetry system which communicates the collected data in real-time to a monitoring website, allowing for efficient personnel response to equipment malfunctions or potential abnormal events.

ENV’s continuous dataset is collected by a multi-parameter data sonde manufactured by Yellow Springs Incorporated (YSI). The specific instrument used to monitor Wildcat Creek is the 6600 V2-2 sonde, which collects 15-minute data for depth, dissolved oxygen (DO), turbidity, specific conductivity, temperature, and pH.

The water quality data collected at the ENV5 station is complemented and informed by grab sample bacteria data, meteorological data, and flow data. These datasets are provided by a Hydrologic Services tipping bucket rain gauge, a Vaisala WXT520 meteorological station located in the Fort and operated by ENV, a Campbell Scientific 451 Series pressure transducer (CS451) located in Wildcat Creek, and a SonTek IQ area-velocity meter installed in Wildcat Creek shortly downstream from the ENV5 station.

1.3 Watershed Description

Figure 1 shows the permanent ENV5 monitoring location and the drainage area corresponding to the monitoring station. The area in gray shows the drainage area captured by the permanent station, ENV5. This drainage area is located entirely within Fort Jackson, and drains approximately two square miles of the Fort’s urbanized area.

Figure 1: Fort Jackson Monitoring Area

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While the ENV5 sampling location is a representative sampling location for Fort Jackson, the watershed draining to this point changed during the monitoring period. The 1,000-year storm event that occurred October 4, 2015 destroyed the dam on Semmes Lake, through which the majority of the ENV5 watershed had previously flowed.

After October 4, Semmes Lake returned to a more stream-like flow. Aerial images of Semmes Lake are shown in Figure 2, below. The 2014 image was collected by Richland County before the historic flood event. The 2015 image was collected by Woolpert on October 6th after the historic flood. While this shift in hydraulics may have an effect on bacteria and DO concentrations downstream, that effect has not been definitively documented with the data collected during this monitoring period. The Fort has adhered to the quarterly monitoring schedule to continue to gain a broader picture of bacteria concentrations leaving the Fort.

Figure 2: Aerial images of Semmes Lake Before (left) and After (right) the Storm on October 4, 2015

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2 Methods The section below describes the methods followed in the ENV monitoring program during the January 2015 – June 2017 data collection period. It includes a description of the procedures for data collection and equipment maintenance, the techniques used to process the collected data, and the assumptions made in comparing the processed data to regulatory guidelines and standards.

2.1 Data Collection

The conclusions drawn from a water quality monitoring program are only as accurate and reliable as the quality of the collected dataset. As such, ENV places a high priority on maintaining its water quality equipment, and incorporating other data only from reliable sources.

2.1.1 Continuous Water Quality Data

The continuous water quality monitoring dataset analyzed in this report was collected by means of a Yellow Springs Instrument (YSI) 6600 V2-2 sonde equipped with sensors that measure the pH, specific conductivity, temperature, dissolved oxygen, turbidity, and depth of the creek at 15-minute intervals. The sonde was removed from the station periodically for calibration. Calibration procedures outlined by the manufacturer were followed to ensure that the water quality sensors were collecting accurate readings.

2.1.2 Grab Sample Water Quality Data

ENV’s NPDES permit required sampling to begin on or after July 1, 2015. In December 2014, the Fort finalized its monitoring plan, titled “Fort Jackson TMDL Monitoring and Assessment Plan for the Gills Creek Watershed: Fecal Coliform.” Due to the change in preferred indicator bacteria by SCDHEC for fresh water recreational use from fecal coliform bacteria to Escherichia coli (E. coli), the pollutant of concern (POC) sampled by Fort Jackson was E. coli, rather than the POC listed in the TMDL.

ENV began a grab sampling program at the location of the permanent monitoring station, ENV5, following the installation of this station and per the Fort’s TMDL Monitoring and Assessment Plan. Under this program, bacteria grab samples are collected by field staff throughout storm event hydrographs, and samples are analyzed by a certified laboratory for E. coli. Samples can only be collected when conditions are safe for field personnel and when sufficient time is allowed for the samples to be delivered to the lab within the required maximum holding time for bacteria samples and within working hours. For these reasons, the dataset of bacteria samples collected during this reporting period does not contain an adequate number of samples for statistical analysis. As additional samples are collected in the future, further analysis will be performed and reported.

2.1.3 Rainfall Data

A HyQyest Solutions tipping bucket rain gauge was installed by ENV on Fort Jackson property during July of 2015.

Prior to this time, rainfall data was obtained via a Weather Underground Personal Weather Station (PWS) (KSCCOLUM29) located within Ft. Jackson.1 This station is located near the corner of Semmes Rd and Chestnut Rd.

Following the installation of a dedicated ENV rain gauge in July of 2015, rainfall data from this location was used to inform the analysis of water quality conditions at ENV5. Daily rainfall data for the monitored period was used for the analysis of water quality data on a seasonal scale. Following manufacturer recommendations, cleaning and a verification test is performed on the HyQyest Solutions tipping bucket rain gauge every six (6) months to ensure it is functioning properly.

2.1.4 Flow Data

Flow data was calculated using a combination of direct measurement and the stage-discharge relationship. Direct velocity and depth measurements were taken in real time using a SonTek IQ installed within a box culvert, and

1 http://www.wunderground.com/personal-weather-station/dashboard?ID=KSCCOLUM29

December 2017 Fort Jackson Environmental Division 5 discharge was calculated using the continuity equation (Q=VA). When depth in the box culvert fell below the minimum operating depth of the IQ (0.4 feet), discharge measurements were performed using a SonTek FlowTracker, and a Campbell CS451 pressure transducer was used to determine stage in 5 minute intervals. The resulting stage-discharge relationship was used only during periods when the level of flow failed to exceed the IQ’s minimum operating depth.

2.2 Data Processing

Before performing any type of analysis on the continuous water quality data, the raw dataset was corrected using specialized software called AQUARIUS, specifically designed for continuous water quality data preprocessing. Time series datasets are corrected to ensure that erroneous data that are not representative of true in-stream conditions are not used in the data analysis process. Such erroneous data can be caused by sensor malfunctions, debris entrapment in the sonde casing, or other unpredictable equipment issues. Because this data is not representative of true in-stream conditions, it is removed before data analysis is performed to avoid introducing any bias into the dataset. Where needed, approximation methods such as linear interpolation and averaging techniques were used to fill data gaps of less than four hours. On days when the sonde was removed for calibration or redeployed after calibration, a complete dataset was not captured. In order to avoid influencing daily averages from the inclusion of partial days of data, the entire day of the dataset was discarded during these calibration periods.

2.3 Data Analyses and Water Quality Standards

Daily and seasonal analyses were performed on the final ENV5 corrected dataset. The data was then compared to a set of water quality standards set by SCDHEC, listed in Table 1 below. It should be noted that the 50 NTU water quality standard is not intended for continuous water quality data or for stormwater runoff. These standards are used here as a basis for assessing water quality conditions, but an exceedance of these values does not necessarily imply an exceedance of these standards.

Table 1: Water Quality Standards2

Parameter Limit/Range Applicability pH 6.0 – 8.5 Freshwaters

DO

Minimum 5 mg/L Daily average values

Minimum 4 mg/L Instantaneous values

Turbidity Maximum 50 NTU Not explicitly a stormwater standard

Temperature Maximum 90 °F This temperature cannot be exceeded as a result of the discharge of heated liquids

E. coli 126 MPN/100mL Geometric mean

349 MPN/100mL Daily maximum

2.4 TMDL Wasteload Allocations

Portions of Fort Jackson’s urbanized area drain to the Gills Creek watershed, which has two (2) TMDLs developed-one for DO and one for fecal coliform bacteria.

The Gills Creek DO TMDL became effective in July 2010 and includes wasteload allocations for non-point source runoff. The Fort’s urbanized area draining to Gills Creek is included in this TMDL. The proposed pollutant load reductions in the TMDL are biochemical oxygen demand (BOD5) and ammonia and include a reduction of 61% and 22%, respectively. Stormwater discharges are required to meet the percentage reduction or the existing in-stream standard for the pollutant of concern, DO, in accordance with their NPDES Permit. Since approved technology exists to monitor in-stream DO concentrations, Fort Jackson elected to demonstrate compliance with the TMDL by

2 SCDHEC. R.61-68, Water Classifications & Standards. June 22, 2012.

December 2017 Fort Jackson Environmental Division 6 monitoring the in-stream DO levels at a representative location within the urbanized area. The in-stream daily average DO values should not fall below a minimum of 5 mg/L with instantaneous values not reading below 4 mg/L, as seen in Table 1.

The Gills Creek fecal coliform bacteria TMDL became effective in July 2010 and includes portions of Fort Jackson’s urbanized area. This TMDL includes wasteload allocations for non-point source runoff that thereby includes these urbanized areas. The percentage reduction necessary to achieve the target load for station C-001, at Devine Street and Gills Creek, and station C-017, located at Bluff Road and Gills Creek, are 97% and 91%, respectively. Fort Jackson demonstrates compliance with this TMDL by including a bacteria sampling program as part of its monitoring program. Bacteria samples are collected at a range of flow conditions and across multiple seasons in order to characterize bacteria levels in streams draining the Fort’s urbanized area.

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3 Results and Discussion The results presented below summarize data from the permanent station on Wildcat Creek (ENV5) collected from January 2015 through June 2017. Summary statistics are presented, followed by a temporal comparison to show trends both across seasons and years. A focused discussion of the recorded dissolved oxygen and E. coli data is included as well, since these parameters have corresponding TMDL’s in effect.

3.1 Summary Statistics

The tables below contain summary statistics calculated from the water quality dataset collected by the continuous monitoring equipment at the ENV5 station. This dataset ranges from January 2015 through June 2017. In Table 2, summary statistics are calculated from a dataset of daily average values. The daily average dataset is used in order to compare recorded values to SCDHEC daily average standards (DO has such a standard), and also to provide a more representative overview of general stream conditions. Table 3 contains the summary statistics calculated from the 15-minute discrete dataset. This table allows for a comparison to SCDHEC discrete water quality standards, and displays the most extreme maximum and minimum values recorded at the station during the two reporting years.

Table 2: Summary Statistics Calculated with Daily Average Dataset

Summary Statistics: Daily Average Water Quality Values, January 2015 - June 2017

Parameter Mean Median Min Max Standard

Deviation

Water Temperature, °F 65 62 44 76 9

Specific Conductivity, mS/cm 0.079 0.078 0.039 0.148 0.015 pH 6.5 6.5 5.6 6.9 0.2

Turbidity, NTU 18.6 10.3 0.4 441.5 30.3

Dissolved Oxygen, mg/L 8.6 8.4 6.4 11.8 1.3

Table 3: Summary Statistics Calculated with 15-minute Continuous Dataset

Summary Statistics: Discrete Water Quality Values, January 2015 - June 2017

Parameter Mean Median Min Max Standard

Deviation

Water Temperature, °F 65 66 39 89 11

Specific Conductivity, mS/cm 0.079 0.078 0.019 0.221 0.016 pH 6.5 6.5 5.5 7.3 0.2

Turbidity, NTU 18.1 8.9 0.1 1243.6 43.1

Dissolved Oxygen, mg/L 8.6 8.4 5.3 12.2 1.3

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3.2 Temporal Comparison

To allow for a seasonal comparison of water quality values, Figure 3 and Figure 4 below display the seasonal average values of each of the five monitored water quality parameters during 2015 (blue), 2016 (red), and 2017 (green). As defined in the Fort’s Monitoring and Assessment Plan, the winter season spans January through March, the spring season spans April through June, the summer season spans July through September, and the fall season spans October through December. In the water temperature and dissolved oxygen figures (Figure 3), a clear seasonal pattern is noted, with higher temperatures and lower dissolved oxygen values in the spring and summer months.

This trend is consistent between the three years, with similar average water temperatures and dissolved oxygen levels across monitored years. The seasonal change in dissolved oxygen concentrations results from the seasonal change in water temperature: at higher temperatures, water is able to hold less oxygen in its dissolved form, and concentrations are seen to decrease. In the colder months, when water temperatures drop, dissolved oxygen concentrations increase as the colder water has a higher capacity to retain dissolved oxygen.

Figure 3: Seasonal Average Water Temperature (Left) and DO (Right) Values at ENV5

The specific conductivity, turbidity, and pH data (Figure 4 on the following page) do not show a distinct seasonal trend. However, there are notable differences in the data between 2015 and 2016. These changes are likely related to the historic flood which occurred in October 2015 and resulted in the failure of the Semmes Lake Dam. This dam was not repaired, and Wildcat Creek now flows freely through this area. The effective removal of the upstream control structure appears to have resulted in a consistent increase in specific conductivity at the ENV5 monitoring station. This may be in part due to damage to sewer line infrastructure and subsequent sewer line repair work as a result of the flood event. An alternate explanation is that the absence of Semmes Lake upstream of the station prevented various biological processes from occurring, resulting in water with a higher ionic concentration in Wildcat Creek in the year following the flood.

The turbidity was also observed to be higher in 2016 compared to 2015 and 2017 for all periods except fall of 2015.

During the fall of 2015, extremely high turbidity values were observed in the aftermath of the historic flood. Even following the period of extreme high turbidity values in the fall of 2015, the winter, spring, and summer seasons all showed higher turbidity levels in 2016 as compared to 2015. A likely explanation for this is the continued impact of the severe erosion caused by the October 2015 flood, which appears to have impacted Wildcat Creek turbidity levels throughout the following year. However, the 2017 turbidity values for the winter and spring seasons show lower levels, on par with 2015 values, indicating a return to conditions that were previously observed before the flood event.

The pH at the ENV5 station also showed notable changes between the 2015 and 2016 years in the fall, spring and summer seasons. The pH values recorded during 2016 were lower than those recorded in the same season of 2015 and the pH values recorded in 2017 were also slightly lower than those recorded in 2016. There are many factors

Winter Spring Summer Fall

W at er T em p er at u re

°F

Winter Spring Summer Fall

D is so lv ed O xy ge n m g/

L)

December 2017 Fort Jackson Environmental Division 9 which impact the pH of a water body, and it is difficult to assess what may have caused the slight change in pH characteristics over the past three years.

Figure 4: Seasonal Average Specific Conductivity (Top Left), Turbidity (Top Right) and pH (Bottom) Values at ENV5

3.3 Dissolved Oxygen

In Figure 5 and Figure 6 below, the distribution of the DO dataset at the ENV5 Wildcat Creek monitoring station is displayed. The cumulative frequency distribution displays the 2015 daily average dataset in blue, the 2016 daily average dataset in red, and the 2017 dataset in green. There was little change in the distribution between the 2015 and 2016 datasets. The 2017 dataset is a partial dataset, only containing data from the winter and spring seasons.

Because of this, the 2017 dataset should not be compared directly to the complete 2015 and 2016 datasets. The cumulative frequency distributions demonstrate that all of the daily average values were well above the SCDHEC daily average standard of 5 mg/L, with a minimum of 6.5 mg/L, 6.4 mg/L, and 7.4 mg/L observed in 2015, 2016, and 2017, respectively. When the 2017 dataset is updated to include a full year of data, the minimum DO concentration will likely be lower than what was observed in this partial dataset.

The box-and-whisker plot (Figure 6) shows summary statistics for each season from winter 2015 to spring 2017, calculated using the discrete 15-minute DO dataset. This figure shows the instantaneous minimum and maximum values. The seasonal pattern in DO (discussed in the “temporal comparison” section) is clearly seen, with higher DO levels in the fall and winter seasons and lower DO levels in the spring and summer. This figure allows for a comparison of the data to the SCDHEC discrete minimum DO standards of 4 mg/L. All of the recorded January 2015 - June 2017 DO values fell well above this minimum standard.

These two figures demonstrate the overall health of Wildcat Creek in the vicinity of ENV5 with respect to dissolved oxygen.

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0.11

Winter Spring Summer Fall

Sp ec if ic

C o n d m

S/ cm

Winter Spring Summer Fall

Tu rb id it y (N

TU

5.0

5.4

5.8

6.2

6.6

7.0

Winter Spring Summer Fall p H

-) 2015

December 2017 Fort Jackson Environmental Division 10

Figure 5: Distributions of Daily Average DO Values at ENV-5 (Note: 2017 dataset is a partial dataset and should not be compared directly to the 2015 and 2016 distributions.)

Figure 6: Seasonal Box and Whisker Distributions Displaying Discrete DO Data

6 7 8 9 10 11 12

C u m m u la ti ve

F re q u e n cy

Dissolved Oxygen (mg/L)

Cumulative Frequency Distribution ENV5 - Daily Average Dissolved Oxygen

January 2015 - June 2017

Win '15 Spr '15 Sum '15 Fall '15 Win '16 Spr '16 Sum '16 Fall '16 Win '17 Spr '17

D is so lv e d

O xy ge n m g/ L)

Seasonal Continuous Monitoring Statistics ENV5 - Discrete Dissolved Oxygen Data

January 2015 - June 2017

50th - 75th Percentile

25th - 50th Percentile

Mean

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3.4 Bacteria

In addition to the continuous water quality monitoring effort in place at the ENV5 station, the Fort also conducts a discrete sample collection program to assess bacteria levels in Wildcat Creek. During the January 2015 – June 2017 monitoring period, 27 grab samples were collected at the ENV5 station during a range of wet and dry conditions and were delivered to certified lab to be analyzed for E. coli, the POC. Table 4 below contains summary statistics for this dataset. Wildcat Creek is classified as a freshwater (FW) waterway by SCDHEC, and therefore has a monthly average E. coli standard of 126 MPN/100 mL, using a geometric mean standard, and a daily maximum E. coli standard of 349 MPN/100 mL. The majority of E. coli samples collected at the ENV5 station during this period showed levels above the daily maximum standard, and the geometric mean of the collected sample dataset is above the monthly average standard. These results indicate that there is a significant source of bacteria in the monitored watershed; however, it is not possible with these results to identify the source of the bacteria. It should also be noted that under the existing Gills Creek TMDL, an MS4 is considered to be in compliance with WLA allocations if it meets the requirements outlined in its NPDES permit. A preliminary comparison of E. coli results to the stream flow at the time of sample collection does not reveal a significant trend, suggesting that there is not a strong correlation between stormwater runoff and bacteria concentrations. Furthermore, the current bacteria dataset does not appear to display any notable seasonality or prevailing increasing or decreasing trend. As additional samples are collected in the future, a more thorough analysis of trends can be conducted.

Table 4: Summary Statistics of E. coli Grab Samples Collected at the ENV-5 Station

Summary Statistics: E. coli Grab Samples, January 2015 – June 2017

Parameter Geometric Mean Median Min Max Count

E. coli 3,294 3,640 320 17,330 27

3.5 Comparison of Pre-Flood and Post-Flood Conditions

Parameter Pre-Flood

Mean

Post-Flood

Mean

Water Temperature (°F)

67 64

Specific Conductivity (mS/cm)

0.065 0.088 pH 6.6 6.4

Turbidity

(NTU)

11.8 22.9

Dissolved Oxygen (mg/L)

8.4 8.7

Table 5: Mean Water Quality Values, January 2015 - June 2017

The table below shows the pre-flood (January 2015 - October 4, 2015) and post-flood (October 5, 2015 - June 2017) mean values generated from the water quality dataset. The pre-flood and post-flood differences are discussed in Sections 3.2 and 3.3.

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4 BMP Implementation The section below discusses the Fort’s plan to implement and evaluate selected BMPs to address the DO and bacteria TMDLs in the Gills Creek TMDL watershed.

4.1 BMP Implementation Prioritized Areas

Fort Jackson’s SMS4 area is approximately 5 square miles which limits the number of areas that can be targeted for BMP implementation.

DO BMP PRIORITIZED AREAS

Proposed BMP: N/A

Prioritized Area:

As discussed in Section 3, the DO data collected at Fort Jackson is meeting the water quality standard and does not require any BMPs to be implemented in order to be in compliance with the TMDL. Areas have not been selected to implement BMPs related to DO at this time.

Underlying Rationale:

N/A

BACTERIA BMP PRIORITIZED AREAS

Proposed BMP: Public Education Program related to Bacteria

Prioritized Area:

This BMP would be implemented in the cantonment area of the Fort and would include targeted educational material towards the specific audiences. Figure 7 shows the watershed areas that contain the urbanized area of the Fort.

Underlying Rationale:

Fort Jackson has a variety of targeted audiences that can be reached through different campaigns. The Fort currently has a public education program, but this will be revamped to include further focus on prioritized groups.

Proposed BMP: Continue Sanitary Sewer System Upgrades

Prioritized Area:

Palmetto State Utility Services (PSUS) continues to perform sewer system upgrades at Fort Jackson, according to their set schedule. These upgrades are focused in the priority areas seen in Figure 8, though have been implemented in other areas of the cantonment area as well.

Underlying Rationale:

Upgrading the sanitary sewer system at the Fort will assist in improving water quality due to correcting any cross connections, repairing any leaks/cracks, and preventing sanitary sewer overflows (SSOs) from occurring in the future. Sanitary sewers are being upgraded throughout the Fort according to a schedule developed by PSUS.

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Proposed BMP: Address Illicit Discharges found During Dry Weather Screening

Prioritized Area:

Fort Jackson developed a schedule for dry weather screening. Each screening point will be visited twice during its assigned year seen in the table below. Figure 8 shows the map for priority areas used for the dry weather screening program.

Phase Screening Point(s)

Timeframe *

A

IDDE-1

IDDE-2

IDDE-3

B

IDDE-4

IDDE-5 2016

C

IDDE-6

IDDE-7

IDDE-8

D

IDDE-9

IDDE-10 2018

Underlying Rationale:

The phases were prioritized based on the high density of aging sewer lines at the Fort, and is a likely source of sanitary sewer overflows and illicit discharges. Within this high priority area of the Fort, there are no outfalls which discharge directly into streams. For this reason, the stormwater system will be sampled at the several locations where the SMS4 exits the Fort’s jurisdiction. The subwatersheds, based on these discharge points, were used to divide the priority area into four sub-areas, to be sampled in four phases. For each of these phases, the relevant discharge point(s) are shown in Figure 8 and are also listed in the table above. During each phase of the dry weather screening program, these screening points will be examined for dry weather flows or suspected illicit discharges twice a year at a minimum. In compliance with Section 4.2.3.2.3.ii.b, the Screening point(s) are the furthest accessible, downstream location in the storm drain system on Fort Jackson property. Although other sub-watersheds are not defined as priority areas, illicit discharges are also eliminated according to the Fort Jackson Illicit Discharge Detection and Elimination Guidance Document. These priority areas will be updated annually to reflect changing priorities.

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Figure 7: Fort Jackson Sub-Watersheds

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Figure 8: Schedule for sewer upgrades and field screening

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4.2 BMPs Considered

DO BMP CONSIDERATION

Proposed BMP: N/A

Action:

As discussed in Section 3, the DO data collected at Fort Jackson is meeting the water quality standard and does not require any BMPs to be implemented in order to be in compliance with the TMDL. If DO data is not meeting the DO standard when data is re-evaluated, then BMPs will be evaluated to determine which would be best for the Fort to implement. At the current time, no BMPs will be implemented.

Explanation of BMP Selection:

N/A

Research on both structural and non-structural BMPs to reduce bacteria levels was conducted to determine which BMPs would be best for Fort Jackson to implement. The Fort will begin implementing the following BMPs and should there be no water quality improvement of the discharges, additional control measures will be considered and changes to this plan will be made accordingly.

BACTERIA BMP CONSIDERATION

Proposed BMP: Public Education Program related to Bacteria

Action:

Upgrade the Fort’s public education program. This includes developing/updating informative brochures, and guidance for specific audiences. These may address observing and reporting illicit discharges, pet waste, and proper disposal of certain wastes. Brochures may be distributed to:

o Neighborhoods

▪ Proper pet waste disposal, illicit dumping, and other disposal of certain wastes.

o School Classes

▪ Proper pet waste disposal and illicit dumping.

o Pet Owners

▪ Proper pet waste disposal.

o High Priority Facility Managers

▪ Proper disposal of wastes, illicit dumping, proper chemical storage, and proper vehicle cleaning.

o Maintenance Staff/Contractors

▪ Proper disposal of wastes, illicit dumping, proper chemical storage, and proper vehicle cleaning.

The Fort will evaluate the number and location of current pet waste stations and see if an Increase in the number of pet disposal stations is necessary, throughout the cantonment area. The Fort will educate the public on the importance of proper disposal of pet waste and what it means for water quality.

Explanation of BMP Selection:

Bacteria is naturally occurring at a certain background level. One thing that can help minimize the amount of extra bacteria added to waterways is educating people on what they can do to help, including the targeted items listed above. The results from the Fort’s public education programs/participation will vary throughout the different watershed sub-basins. The estimated load reductions cannot be predicted prior to program implementation.

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Proposed BMP: Continue Sanitary Sewer System Upgrades

Action:

Palmetto State Utility Services (PSUS) continues to perform sewer system upgrades at Fort Jackson. According to their study released prior to the issuance of this permit, upgrades to the sewer system at Fort Jackson has reduced inflow and infiltration by almost 20% and has also significantly reduced the number of SSOs occurring on post.

Explanation of BMP Selection:

Bacteria is naturally occurring at a certain background level. By upgrading aging sanitary sewer lines, cross connections will be reduced, leaks/cracks will be repaired, and SSOs will be reduced.

Proposed BMP: Address Illicit Discharges found During Dry Weather Screening

Action:

As discussed in Section 4.1, dry weather screening is performed according to the Fort Jackson Illicit Discharge Detection and Elimination Guidance Document. This document also describes the procedures used to track illicit discharges.

Unlike other MS4s, Fort Jackson does not have an escalation procedure as a part of the Enforcement Response Plan, as all of the utilities and structures on the Fort belong to the Federal Government. Once the source of the illicit discharge has been determined, Fort Jackson shall:

o Notify the necessary personnel on the Fort of the problem no later than 48 hours from the time the illicit discharge is confirmed.

o Request the necessary personnel (responsible party) to conduct all necessary corrective actions to eliminate the non-stormwater discharge within 30 days. When, and if, elimination will take longer than 30 days, Fort Jackson will document correspondence and establish a schedule for elimination.

o Conduct a follow-up investigation and/or field screening, to verify that the discharge has been eliminated upon being notified that the discharge has been eliminated.

By eliminating illicit discharges, overall stream health may benefit by removing the addition of untreated discharges that contribute high levels of pollutants. These pollutants may include heavy metals, toxics, oil and grease, solvents, nutrients, viruses, and bacteria to receiving waterbodies. Eliminating this non-stormwater flow may help prevent the degradation of the receiving streams water quality.

Explanation of BMP Selection:

After potential illicit discharges are reported or determined, they are tracked following the Fort Jackson Illicit Discharge Detection and Elimination Guidance Document procedures. Once they are determined to be illicit discharges, they correct the illicit discharge by requesting the responsible party take the appropriate corrective actions. Correcting the determined illicit discharges will benefit water quality and should lower the pollutants in the receiving waterbody and decrease the dry weather loads and bacteria contribution.

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4.3 BMP Implementation Schedule

The following schedules should be followed and adjusted, as necessary, for implementing the BMPs described above.

During this time frame, monitoring will continue as described in the Fort Jackson Monitoring and Assessment Plans for both DO and bacteria. Field screening will also continue following the reported schedule. The monitoring procedures will be adjusted as needed.

Prior to every Annual Report, progress on the schedule for implementing the BMPs will be determined and the collected data will be analyzed to see where progress has been made. The schedule will be adjusted, as needed.

DO BMP IMPLMENTATION SCHEDULE

Proposed BMP: N/A

Schedule:

The DO data collected at Fort Jackson is meeting the water quality standard and does not require any BMPs to be implemented in order to be in compliance with the TMDL. If DO data is not meeting the DO standard when data is re-evaluated, then BMPs will be evaluated to determine which would be best for the Fort to implement and a schedule will be determined.

Monitoring will continue to be collected as described in the Fort Jackson Monitoring and Assessment Plan.

Measure of Progress:

Data will be evaluated prior to every biennial report and the schedule will be adjusted, as needed.

BACTERIA BMP IMPLEMENTATION SCHEDULE

Proposed BMP: Public Education Program related to Bacteria

Schedule:

Measure of Progress:

The progress from this BMP will be measured with the continued field screening and continuous monitoring that are described in the Fort Jackson Illicit Discharge Detection and Elimination Guidance Document and the TMDL Monitoring and Assessment Plan. Progress can be measured by evaluating the data collected and seeing what changes overall have occurred, if any.

Update Public Education Material/Adjust Plan

Continue to Monitor

Evaluate Data and Document Progress

December 2017 Fort Jackson Environmental Division 19

Proposed BMP: Continue Sanitary Sewer System Upgrades

Schedule:

PSUS will continue their effort to upgrade the sanitary sewer system according to their schedule and contract.

Measure of Progress:

The progress from this BMP will be measured with the continued field screening and grab samples collected as described in the Fort Jackson Illicit Discharge Detection and Elimination Guidance Document and the TMDL Monitoring and Assessment Plan. Any available numbers from PSUS will also be used in evaluating the progress of this BMP, including a comparison in the number of SSOs that occur each year at the Fort.

Proposed BMP: Address Illicit Discharges found During Dry Weather Screening

Schedule:

Measure of Progress:

The Fort currently tracks illicit discharges and requires the appropriate corrective action to be taken to eliminate the determined illicit discharges. This program will continue and will be evaluated by determining the number of illicit discharges that are traced to the sanitary sewer system and also based on the bacteria grab samples collected.

4.4 BMP Implementation Evaluation

In order to evaluate the effectiveness of the implemented BMPs, monitoring will continue per the TMDL Monitoring and Assessment Plan, for both the DO and E. coli POCs. This BMP implementation schedule will continue as stated through the current permit term and the next permit term with continued monitoring to evaluate the effectiveness of the BMP(s) installed. This report will be revised based on the evaluated data collected on the implemented BMPs throughout the current and next permit term. Progress on the TMDL Implementation and Analysis will be documented in the Annual Reports. The schedule and plans listed in this document will be included as part of the re-application process. If necessary, BMPs will be adjusted and additional control measures will be implemented in order to achieve progress towards addressing the TMDLs WLA.

Evaluate Data and Document Progress

Continue to Track, Eliminate, and Document

Illicit Discharges

Adjust Program, As Needed