Fort_Jackson_Monitoring_Plan_DO.PDF

Fort Jackson December 2014 TMDL Monitoring and Assessment Plan-Gills Creek

FORT JACKSON

TMDL MONITORING AND ASSESSMENT PLAN

GILLS CREEK WATERSHED: DISSOLVED OXYGEN

2562 Essayons Way Fort Jackson, SC 29207 803-751-6858

December 2014

PREPARED IN ACCORDANCE WITH SCDHEC PERMIT #SCR030000

Table of Contents

*Table of Contents follows section numbers of #SCR030000.

3.2 TMDL Monitoring and Assessment

3.2.1 Introduction

3.2.1.2 Monitoring Plan Requirements

3.2.1.2.1.b Requirements to Monitor the Pollutants of Concern

3.2.1.2.1.i-ii Monitoring and Assessment Plan Details

3.2.1.2.1.iii Monitoring and Assessment Plan Strategy

3.2.1.2.1.d Reporting

Appendix A: Fort Jackson Gills Creek Monitoring Map

List of Tables Table 1: Monitoring Plan Details

Table 2: 3.2.1.2.1.b.i.1-5 Samples and Measurements

Table 3: 3.2.1.2.1.b.iv-x Sampling Details

List of Acronyms and Abbreviations

BOD5 Biochemical Oxygen Demand

CFU Colony Forming Units

DO Dissolved Oxygen

MEP Maximum Extent Practicable

MPN Most Probable Number

POC Pollutant of Concern

SCDHEC South Carolina Department of Health and Environmental Control

TMDL Total Maximum Daily Load

WLA Wasteload Allocation

WQMS Water Quality Monitoring Stations

WWTP Waste Water Treatment Plant

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FORT JACKSON

TMDL MONITORING AND ASSESSMENT PLAN

The following monitoring and assessment plan was developed to meet the requirements of Section 3 of

SCDHEC SMS4 permit number SCR030000.

3.2 TMDL Monitoring and Assessment

3.2.1 Introduction

A Total Maximum Daily Load (TMDL) has been developed for dissolved oxygen (DO) in the Gills Creek watershed, which includes portions of the urbanized area within Fort Jackson. The TMDL became effective in July 2010 and includes wasteload allocations for non-point source runoff that thereby includes these urbanized areas. The proposed pollutant load reductions in the TMDL are biochemical oxygen demand (BOD5) and ammonia. 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, Fort Jackson will demonstrate compliance with the TMDL by monitoring the in-stream standard of DO at a representative location within the urbanized area.

3.2.1.2 Monitoring Plan Requirements

3.2.1.2.1.b Requirements to Monitor the Pollutants of Concern

As stated in Permit Number SCR030000, the following topics will be addressed in Table 1 and Table 2.

i. Samples and measurements taken for the purpose of the TMDL Monitoring Plan shall:

(1) Be representative of the SMS4 discharges,

(2) Be reasonably distributed in time, while maintaining representative sampling,

(3) Not be terminated for the purpose of preventing the analysis results from a permit or water quality violation,

(4) Describe and consider frequency, mass and/or rate of discharge, as appropriate, and,

(5) Be expressed in terms of units or measurements consistent with the requirements contained in the WLA.

ii. The information contained in the TMDL Monitoring Plan shall include:

(1) Monitoring locations, appropriate for representative data collection,

(2) Explanation of why monitoring is being conducted for selected locations,

(3) A description of whether the location(s) are representative and contribute to pollutant loads,

(4) An indication the seasons during which sampling is intended,

(5) The pollutant of concern, or its surrogate(s), as a sampling parameter,

(6) Description of the sampling equipment, and,

(7) A rationale supporting the proposed monitored location(s) as reflective of water quality concerns to the Maximum Extent Practicable (MEP).

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3.2.1.2.1.b.i-ii Monitoring and Assessment Plan Details

Table 1: Monitoring Plan Details

3.2.1.2.1.b.ii.(1) Monitoring location(s) and details on site selection:

In order to better determine Fort Jackson’s contribution to the 74 square mile Gills Creek TMDL watershed, one monitoring station will be installed along Wildcat Creek that drains into Gills Creek.

This station will be located near the Fort Jackson jurisdictional boundary, upstream of the Ewell Rd crossing over Wildcat Creek.

3.2.1.2.1.b.ii.(2) Explanation of why monitoring is being conducted for selected location(s):

Due to the large size of the Gills Creek watershed, multiple entities discharge into the watershed and contribute to the TMDL. The majority of Fort Jackson’s urbanized area, which is similar to the cantonment area boundary, drains to the Wildcat Creek subwatershed of the Gills Creek overall watershed. The station will be installed at the location discussed above, as this site had the largest drainage area and largest amount of urbanized area among possible station candidates, in addition to containing a drainage area that is entirely within Fort Jackson. This potential location will provide a general assessment of dissolved oxygen within the Fort Jackson urbanized area.

3.2.1.2.1.b.ii.(3) Description of whether the location(s) are representative of the MS4 discharge and contribute to pollutant loads:

The selected location provides the most representative data for Fort Jackson’s urbanized area in the

Gills Creek watershed due to the size of the subwatershed and the amount of urbanized area within the subwatershed. Approximately 22 square miles of the Gills Creek watershed is within Fort Jackson’s boundary. Of these 22 square miles, only approximately 4.7 square miles are urbanized area in Fort

Jackson. The proposed monitored subwatershed area is approximately 2 square miles, of which almost entirely is within Fort Jackson’s urbanized area. The selected location drains approximately 40.5% of the total urbanized area within Fort Jackson.

3.2.1.2.1.b.ii.(4) Indication of the seasons during which sampling is intended:

Multiple samples will be collected for storm events at least once per season. Seasons will be described as:

Winter: January 1 to March 31

Spring: April 1 to June 30

Summer: July 1 to September 30

Fall: October 1 to December 31

Samples taken for each storm event will be reasonably distributed in time, pending appropriate weather conditions, watershed hydrologic response, and sample holding times.

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3.2.1.2.1.b.ii.(5) The pollutant of concern, or its surrogate(s), as a sampling parameter:

The proposed pollutant of concern (POC) to be measured by Fort Jackson is dissolved oxygen (DO).

The DO measurements will be collected in situ at the Ewell Rd monitoring station. Luminescent-based detection for dissolved oxygen data will be collected in accordance with 40 CFR Part 136 and according to the ASTM Standard D888-05 Method C. Fort Jackson will install a multi-parameter data sonde with a sensor for the collection of dissolved oxygen.

3.2.1.2.1.b.ii.(6) Description of the sampling equipment:

Fort Jackson will also use a 6600V2-2 multi-parameter data sonde, from YSI, to collect continuous data for dissolved oxygen. Specifically, the dissolved oxygen sensor is the ROX Optical Dissolved

Oxygen Sensor provided by YSI to be used on a 6600V2 multi-parameter data sonde. This is a luminescent-based dissolved oxygen sensor and is beneficial for making long-term oxygen measurements in a variety of environments.

3.2.1.2.1.b.ii.(7) Rationale supporting the proposed monitored location(s) as reflective of water quality concerns to the

MEP:

Regardless of the location(s) selected for sampling, the contributing watershed will always include sources that impact dissolved oxygen that are unrelated to the MS4 and are not within the authority of the MS4 to control. However, as discussed above in 3.2.1.2.1.b.ii.(3), due to the size of the watershed and the amount of urbanized area, this proposed station will be reflective of dissolved oxygen to the

MEP within Fort Jackson’s urbanized area.

Table 2 discusses how samples and measurements taken for the purpose of the TMDL Monitoring Plan shall meet the five points listed in section 3.2.1.2.1.b.i of the SMS4 permit number SCR030000.

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Table 2: 3.2.1.2.1.b.i.1-5 Samples and Measurements

3.2.1.2.1.b.i.1 Be representative of the SMS4 discharges:

The proposed monitoring location will provide representative data from the MS4, as approximately

96% of the subwatershed area in Fort Jackson drains urbanized area.

3.2.1.2.1.b.i.2 Be reasonably distributed in time, while maintaining representative sampling:

Fort Jackson will collect measurements for dissolved oxygen that are reasonably distributed in time, to characterize water quality to the MEP.

3.2.1.2.1.b.i.3 Not be terminated for the purpose of preventing the analysis results from a permit or water quality violation:

Fort Jackson will not terminate sampling for the purpose of preventing the analysis results from a permit or water quality violation.

3.2.1.2.1.b.i.4 Describe and consider frequency, mass and/or rate of discharge, as appropriate:

Fort Jackson will install a Sontek sensor for the direct measurement of continuous flow rates.

3.2.1.2.1.b.i.5 Be expressed in terms of units or measurements consistent with the requirements contained in the WLA:

Sample concentrations for DO will be collected by the YSI 6600-V2 multi-parameter data sonde and expressed as mg/L. This is consistent with the water quality standard for DO in freshwater as stated in the TMDL.

3.2.1.2.1.b.iii Monitoring and Assessment Plan Strategy

The TMDL monitoring plan for Fort Jackson is focused on dissolved oxygen. Samples and measurements collected will be used to characterize the quality and quantity of the permitted discharges to evaluate the progress toward the WLA and/or WQS attainment. In order to do this, Fort Jackson will implement the following strategies to the MEP:

In-stream monitoring, Outfall monitoring.

The monitoring location(s) discussed above in Table 2 was selected based on the following checked boxes: Monitoring locations must include one/all/a combination of the following:

% MS4 area draining to the WQMS, at least 25%, Collection of a representative contributing watershed, Inclusion of the entire TMDL watershed within the MS4.

Table 3 discusses how samples and measurements taken for the purpose of the TMDL Monitoring Plan shall meet the requirements of 3.2.1.2.1.b.iv-x of the SMS4 permit number SCR030000.

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Table 3: 3.2.1.2.1.b.iv-x Sampling Details

3.2.1.2.1.b.vi Method Descriptions:

Luminescent-based detection for dissolved oxygen data will be collected in accordance with 40 CFR

Part 136 and according to the ASTM Standard D888-05 Method C. This luminescence-based sensor procedure measures the light emission characteristics from a luminescence-based reaction that takes place at the sensor-water interface. A light emitting diode (LED) provides incident light required to excite the luminophore substrate. In the presence of dissolved oxygen the reaction is suppressed. The resulting dynamic lifetime of the excited luminophore is evaluated and equated to DO concentration.

3.2.1.2.1.b.vii When no approved analytical method is used:

Not applicable

3.2.1.2.1.b.viii Sampling minimum:

For the monitoring location, in-situ DO measurements shall be collected, at a minimum, of once per season per year.

3.2.1.2.1.b.ix Sample analysis:

In situ measurements for dissolved oxygen will be recorded for DO, the POC.

3.2.1.2.1.b.x Tidal waters:

Not applicable

3.2.1.2.1.d Reporting

Fort Jackson will report on the progress of the characterization of the POC to the Gills Creek watershed.

Resulting data will be included in every annual report following the commencement of monitoring for

TMDL pollutant characterization.

Appendix A

Gills Creek Monitoring Map

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