Shoal Creek Watershed Assessment
November 2009
Produced for:
100 S. Hill Street Griffin, GA 30224
Produced by:
2110 Powers Ferry Road SE Suite 202 Atlanta, GA 30339 Shoal Creek Watershed Assessment November 2009
Table of Contents
List of Tables ...... iii
List of Figures ...... iv
Appendices ...... iv
1 Executive Summary...... 1
2 Introduction...... 3
3 Shoal Creek Watershed Characterization...... 4 3.1 City of Griffin, Shoal Creek Watershed, and Wastewater Service Area...... 4 3.2 Natural Features ...... 10 3.3 Environmentally Sensitive Areas ...... 10 3.4 303(d) Listed Waterbodies...... 13 3.4.1 Biota (sediment)...... 13 3.4.2 Downstream Impairment ...... 14 3.5 Significant Facilities and Activities ...... 14 3.5.1 Water Supplies...... 14 3.5.2 Wastewater and Stormwater Facilities...... 14 3.5.3 Agricultural Operations ...... 15 3.5.4 Solid and Hazardous Waste and Toxic Releases ...... 15
4 Data Collection...... 16 4.1 Water Quality Data ...... 16 4.1.1 Monitoring Stations ...... 16 4.1.2 Monitoring History ...... 20 4.2 Land Use Data...... 22 4.3 Biological/Habitat Data...... 26 4.3.1 2000 Biological/Habitat Data ...... 26 4.3.2 2004/2005 Biological/Habitat Data ...... 26 4.3.3 2008/2009 Biological/Habitat Data ...... 27 4.4 Other Monitoring Data...... 27 4.4.1 Geomorphic Assessment...... 27 4.4.2 Sediment Evaluation...... 28 4.4.3 North Griffin Regional Detention Pond Water Quality Monitoring ...... 28
i Shoal Creek Watershed Assessment November 2009
4.4.4 Oakview Detention Pond Water Quality Monitoring ...... 29 4.4.5 LSPC Hydrology and Water Quality Modeling...... 29
5 Data Analysis...... 31 5.1 Water Quality Analysis...... 31 5.1.1 Temperature...... 32 5.1.2 Oxygen Demand ...... 32 5.1.3 Turbidity ...... 35 5.1.4 Nutrients ...... 36 5.1.5 Metals and Toxic Organic Compounds ...... 39 5.1.6 Sediment Samples...... 43 5.1.7 Fecal Coliform...... 45 5.1.8 North Griffin Regional Detention Pond...... 47 5.2 Land Use Analysis ...... 48 5.3 Biological Analysis ...... 51 5.3.1 Biological/Habitat Assessment 2000 ...... 51 5.3.2 Biological/Habitat Assessment 2004/2005 ...... 51 5.3.3 Biological/Habitat Assessment 2008/2009 ...... 53 5.3.4 Biological/Habitat Summary ...... 54
6 Constituents & Areas of Concern...... 56
7 References ...... 58
ii Shoal Creek Watershed Assessment November 2009
List of Tables
Table 3-1. Listed Species in Spalding County...... 11
Table 3-2. TMDL for Wasp Creek ...... 13
Table 4-1. Monitoring Stations...... 17
Table 4-2. Summary of Sampling Conducted in the Shoal Creek Watershed Since 2001...20
Table 4-3. Sample Events ...... 20
Table 4-4. Land Use Classification...... 23
Table 5-1. Consensus-Based Effect Concentrations for Pollutants in Freshwater Sediments44
Table 5-2. North Griffin Regional Detention Pond Pollutant Removal Efficiency...... 48
Table 5-3. Impervious Area of Monitoring Station Subwatersheds ...... 51
Table 5-4. Summary of Biological Assessments ...... 54
Table 5-5. Scores for Comparable FIBI Metrics from 2005 to 2009 Assessments ...... 55
iii Shoal Creek Watershed Assessment November 2009
List of Figures
Figure 3-1. City of Griffin Watersheds ...... 6
Figure 3-2. Shoal Creek Wastewater Service Area, Permitted Facilities, Septic Systems, and 303(d) Streams ...... 7
Figure 3-3. Aerial Photograph of Shoal Creek Service Area...... 8
Figure 3-4. Topographic Map of Shoal Creek Service Area...... 9
Figure 3-5. National Wetland Inventory Wetlands in Shoal Creek Service Area...... 12
Figure 4-1. Water Quality Monitoring Stations ...... 18
Figure 4-2. City of Griffin Water Quality Reference Monitoring Station ...... 19
Figure 4-3. Existing Land Use and Sampling Site Subwatersheds...... 24
Figure 4-4. Future Land Use and Sampling Site Subwatersheds...... 25
Figure 5-1. Existing Land Use by Subwatershed...... 50
Appendices Appendix A - Shoal Creek Stream Gage and Rainfall Data Appendix B- Habitat/Biological Assessments (2000, 2005 & 2009) Appendix C - Shoal Creek Geomorphic Assessment Appendix D - Shoal Creek Sediment Evaluation Appendix E - Watershed Hydrology Modeling Report for the City of Griffin Watersheds Appendix F - Water Quality Report for the City of Griffin Watersheds Appendix G - Water Quality Assessment Charts and Graphs Appendix H - Priority Pollutant Scan Results
iv Shoal Creek Watershed Assessment November 2009
1 Executive Summary
As an integral part of their on-going Stormwater Management Program, and in an effort to prepare for future growth and redevelopment, the City of Griffin recently initiated a comprehensive evaluation of all watersheds within its jurisdiction to determine the overall health of their streams, and to identify needed improvements. This program is consistent with the permitting requirements of the National Pollution Discharge Elimination System (NPDES) in which the Georgia Environmental Protection Division (Georgia EPD) mandates that permittees conduct watershed assessments and prepare watershed protection plans as a prerequisite to permit reissuance or increasing wastewater discharges. In fulfillment of the City’s Stormwater Management Program and NPDES permitting needs, this Watershed Assessment presents and discusses the results of data collection in the Shoal Creek Wastewater Service Area, and identifies the sources of current water quality problems in order to provide a technical foundation for the management strategies to be developed as part of the management plan. Components of the Assessment include: water quality and sediment analysis at twelve sample sites in the Watershed to determine the levels of fecal coliform, nutrients, organic contaminants and metals; and land- use characterization to identify potential stressors to the Watershed. A biological analysis is also included, based on biological/habitat assessments that were conducted as part of the ongoing watershed monitoring, including detailed habitat, macroinvertebrate and fish community assessments. The Shoal Creek Wastewater Service area includes portions of three watersheds, Shoal Creek, Heads Creek, and Wasp Creek, all of which drain to the Flint River. Georgia EPD does not list Shoal Creek on its 303(d) list of impaired streams that do not meet their designated uses. However, the receiving water for Shoal Creek, Wildcat Creek in western Spalding County, is on the not supporting list for fecal coliform. Heads Creek, which accepts flow from two small sub-basins included in the Shoal Creek Assessment, is listed due to impaired biota due to sediment, but the listed reach is approximately two miles downstream of the service area. Wasp Creek, which is in the Shoal Creek service area, is listed for not supporting its designated use of fishing. The criterion violated is Biota. The 303(d) listing attributes the impairments to nonpoint sources. A Total Maximum Daily Load (TMDL) for five miles of Wasp Creek was finalized in 2008. Several data sources were used in this report to evaluate the relative water quality of the Shoal Creek Watershed within the City of Griffin. The data sources are as follows: • An initial Shoal Creek Watershed Assessment (2002) • Current City of Griffin sampling in the Shoal Creek Watershed • Land-use identification within the drainage area of water quality sampling sites • Shoal Creek Sediment Evaluation (2005) • Shoal Creek Geomorphic Assessment (2004) • Three Biological/Habitat Assessment reports (2000, 2005, & 2009) prepared for the City of Griffin Watersheds
Since the initial Shoal Creek Watershed Assessment that was conducted in 2001, monitoring stations have been revised to better reflect the needs of the monitoring program and the conditions of the watershed, and in 2004 the Georgia EPD issued new Watershed Assessment and Protection Plan Guidance documents. Per the Georgia EPD comments on the original Assessment, the City has made the appropriate changes and updated all of the sampling data. This assessment concludes that in the Shoal Creek service area, state water quality standards are being violated based on biota, dissolved oxygen, pH, and fecal coliform. Also of some concern with regards to water quality are occasional high concentrations of phosphorus and total Kjeldahl nitrogen at various sites
1 Shoal Creek Watershed Assessment November 2009 throughout the service area. Additionally, there is some concern about the detection of lead at one of the headwater sample locations. Pollutants detected in the Shoal Creek service area all appear to be originating from non-point sources, which have caused water quality, hydrology, and habitat impacts. Land use analysis reveals that, within the Shoal Creek service area, there is a high percentage of impervious surface cover in the Shoal Creek and Heads Creek Watersheds, which is usually associated with degraded physical and biological stream conditions. A breakdown of existing land use data shows that there is a high percentage of Residential Development, as well as significant areas of Commercial, Industrial, and Institutional land uses in the Shoal Creek service area. Agricultural land exists outside of city limits within the service area. Some growth and development is expected between now and 2024, but there are no projected land use changes that would be expected to significantly affect sediment, nutrients, fecal coliform, dissolved oxygen, or temperature within surface waters.
2 Shoal Creek Watershed Assessment November 2009
2 Introduction
The City of Griffin is seeking reissuance of its National Pollutant Discharge Elimination System (NPDES) permit for its municipal wastewater treatment plant in the Shoal Creek service area. The effluent from Shoal Creek Wastewater Treatment Plant (WWTP) is pumped to the Blanton Mill Spray Application Site and does not discharge directly to Shoal Creek at this time. As a part of issuance of NPDES point source permits, the State of Georgia Environmental Protection Division (Georgia EPD) has adopted a watershed approach for evaluating point and nonpoint sources of pollution and NPDES permit requirements. Georgia EPD requires permit applicants to develop a watershed management plan that addresses ongoing land uses and discharges as well as impacts of future growth and increased discharges that may affect water quality. The Georgia EPD’s May 6, 2004 Guidance for developing the watershed management plan includes three components: a Watershed Monitoring Plan, a Watershed Assessment, and a Watershed Protection Plan (GA DNR 2004). The City of Griffin, in preparation for its wastewater treatment plant NPDES permit renewal, must develop watershed plan documents that meet the Georgia EPD requirements. This NPDES required watershed approach mirrors the City’s assessment and planning approach for its Stormwater Management Program: linking discharge and development activities in the watershed with impacts to water quality, hydrology, and habitat. Since 2001, the City has implemented a monitoring program in coordination with the Georgia EPD for the Shoal Creek Watershed. An initial Watershed Assessment was prepared for Shoal Creek in 2002, and was based on data collected from July through November of 2001. To fulfill NPDES requirements, this Assessment is now being updated to comply with the 2004 Watershed Assessment Guidance (GA DNR 2004). A Shoal Creek Monitoring Plan was prepared in May 2009, and documents the City’s past monitoring program as a formal submittal pursuant to the NPDES permit. The Monitoring Plan describes the watershed, identifies environmental influences in and around the service area, and describes the monitoring sites and methodologies in detail. The Monitoring Plan has been reviewed and approved by the Georgia EPD. This Shoal Creek Watershed Assessment is the second in the series of watershed management plan documents. Per EPD guidance, the objectives of this report are to: 1. Evaluate the current water quality conditions in the Shoal Creek Watershed Service Area and determine whether the waters meet their designated uses. 2. Determine the probable cause of any current impairment by identifying the major point and non- point pollutant sources within the service area watershed. 3. Predict the effects future growth will have on current water quality conditions. 4. Support the development of watershed management strategies to restore and protect the health of the service area watershed and maintain water quality standards for its designated uses. Once the EPD reviews and concurs with this Assessment, a Watershed Protection Plan will be developed as the final component of the watershed management plan.
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3 Shoal Creek Watershed Characterization
3.1 City of Griffin, Shoal Creek Watershed, and Wastewater Service Area The Shoal Creek watershed, depicted in Figure 3-1, is located in the Flint River Basin, and its headwaters are located on the west side of Griffin, Georgia. Located south of the metro Atlanta Region, the City of Griffin is 13.9 square miles in area and had a population of 23,451 at the time of the 2000 census. As with many cities and towns in Georgia, the City of Griffin sits astride a major watershed boundary. Originally situated around a railroad junction, the City of Griffin has developed along the divide between the Upper Ocmulgee River system to the east and the Upper Flint River system to the west. Six watersheds within the City of Griffin are contained within these two river systems (see Figure 3-1). The Cabin Creek watershed eventually drains to the Ocmulgee River. The Heads Creek, Shoal Creek, Wasp Creek, Honey Bee Creek, and the Potato Creek watersheds eventually drain to the Flint River. The City of Griffin lies at the headwaters of all these watersheds. The Shoal Creek Watershed covers approximately 3,127 acres on the western side of Griffin. The far east boundary of the watershed is located downtown, near 9th Street. To the south the boundary generally follows Poplar Street. To the north the boundary follows along the Norfolk Southern rail line heading toward Experiment. The watershed eventually stretches from West McIntosh Road in the north to the intersection of the Highway 19 By-Pass and the Norfolk Southern rail line in the south. The Georgia Experiment Station, Griffin Tech Institute, The Griffin Water Works and Griffin High School are within the watershed in the areas along the By-Pass. West of the by-pass the Watershed includes the Griffin Country Club and the surrounding residential area, and outside the City boundaries it encompasses portions of the State Experimental Farms. The engineering design award winning North Griffin Regional Detention Pond is found near Ellis Road. This facility is improving water quality in the Shoal Creek Watershed by filtering stormwater through a wetland system in a tributary of Shoal Creek. The City of Griffin operates the Shoal Creek Wastewater Treatment Plant (WWTP) in tandem with the Blanton Mill Land Application System to service the western portion of Griffin and Spalding County. The Shoal Creek service area is approximately 9,400 acres and includes portions of the Shoal Creek, Heads Creek, and Wasp Creek watersheds. The boundaries of the Shoal Creek service area and the three watersheds included within it are shown in relation to the City of Griffin in Figure 3-2. The City of Griffin has no current plans to expand the Shoal Creek service area. The most common land uses in the Shoal Creek service area are residential areas. Significant commercial areas exist within the service area as well as a few industrial developments and institutional areas. Agricultural land exists outside of city limits within the service area. The Shoal Creek service area within the City of Griffin consists of the main stem of Shoal Creek and one major tributary on the southwest side of Griffin. The main Shoal Creek stem originates near Lyndon Avenue and flows generally west under the bypass, through the State Experimental Farms, under North Pine Hill Road, into the Griffin Country Club Lake, and out of the Lake beyond the City boundary where the southwest tributary joins. The southwest tributary originates in the Oakdale area, flows southwest under the bypass and Carver Road, flows directly west under South Pine Hill Road, flows to the northwest under Poplar Street and State Route 16, skirts the western boundary of the Griffin Country Club golf course, and joins with the main Shoal Creek stem just west of the City boundary. A significant portion of the Heads Creek watershed is included within the service area. This area is on the north side of the City and west of the Norfolk Southern rail line. West of the service area, Shoal Creek
4 Shoal Creek Watershed Assessment November 2009 joins with Heads Creek to form Wildcat Creek in western Spalding County. Wildcat Creek flows a short distance before entering the Flint River. Wasp and Little Wasp creeks, although not direct tributaries to Shoal Creek, are included in the Shoal Creek service area and drain the southern portion of the service area. A 2006 aerial photograph of the service area is shown in Figure 3-3, and a topographic map of the service area is shown in Figure 3-4.
5 Shoal Creek Watershed Assessment November 2009
City of Griffin Watersheds Waterway Cabin Creek Watershed Major Waterway Heads Creek Watershed Waterbody Honey Bee Creek Watershed City Limits Potato Creek Watershed 8-Digit HUC Boundary Shoal Creek Watershed
Wasp Creek Watershed Indi an T C C ho r F le mp eek l ar T i C so n re n o t e w k C W R k re ree e a i C k l o v r i ea g o e B a r L l s R o
e n iv y g e
C r B
r r a e n e c k h
k H ee eads C Cr reek e om es bl ou Tr
reek ds C Hea C a b Sho in Sho al Cr C al C eek re re e ek k G r a p B e r u C s I re h so y n e B k B C r u r a c e nc k e h C k re P e o k F t la H a
t L t o o C W i n r t ee t C a e l k e y s r
e p W B e
C e k a e
r s e p C e
r k C k e
e r e e e r B k e e Ocmulgee C v Flint ils k
h k c C River ir e re River B e e
r k Basin Basin C
s
T E n u d i i
k r e l n C E p r ik e e e k
C
r e ek e e Cr Hardin Creek k r rne Tu City of Griffin Watersheds 0241 Kilometers NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet Turner Creek Map produced 08-10-2009 - H. Fisher 0241 Miles
Figure 3-1. City of Griffin Watersheds
6 Shoal Creek Watershed Assessment November 2009
Septic Systems Cabin Creek Service Area
Permitted Facilities Potato Creek Service Area
Stormwater Facilities Shoal Creek Service Area
k
Cabin Creek Watershed e City Limits e
r
C Heads, Shoal, and Wasp Creeks Watersheds
s
305b/303d Assessed Streams d
a
Potato Creek Watershed e
Not Supporting H Supporting Other Watersheds F Notlin Assessed t R iv er Oakview Detention Pond
North Griffin Regional Detention Facility S R 9 2
H RD INTOS W MC
N
EX
P
RESS
W
AY
Shoal Creek
1 4 / 9 1
Y
W Sh H oa l C re ek
r e W TAYLOR ST iv
R H W t Y
6 1 n 1 9 R / i S 4
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Shoal Creek WWTP AEP Industries (TRI) Shoal Creek RD N LO Wasp Creek BU Landfill ZE RD N H O o S n M e IA y L IL B W e e k e C re Shoal Creek - r C e F s e in k l lk a E Blanton Mill Site t C k r e ee (NPDES) k re
C t a l F LaFarge Griffin Concrete Plant (TRI)
Shoal Creek Wastewater Service Area, Permitted Facilities, 0120.5 Septic Systems, and 303(d) Streams Kilometers
NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 0120.5 Map produced 07-30-2009 - P. Cada Miles
Figure 3-2. Shoal Creek Wastewater Service Area, Permitted Facilities, Septic Systems, and 303(d) Streams
7 Shoal Creek Watershed Assessment November 2009
Legend
City Limits Existing Service Areas Cabin Creek Potato Creek Shoal Creek
Cabin Creek and Shoal Creek Wastewater Service Area 0120.5 2006 Aerial Coverage (source: NAIP) Kilometers
0120.5 NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet Miles Map produced 07-30-2009 - P. Cada
Figure 3-3. Aerial Photograph of Shoal Creek Service Area
8 Shoal Creek Watershed Assessment November 2009
Legend
City Limits Existing Service Areas Cabin Creek Potato Creek Shoal Creek
Shoal Creek Wastewater Service Area 00.81.60.4 USGS Topographic Map Kilometers
NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 000.4 .81.6 Map produced 07-30-2009 - P. Cada Miles
Figure 3-4. Topographic Map of Shoal Creek Service Area
9 Shoal Creek Watershed Assessment November 2009
3.2 Natural Features The watershed occurs within the Southern Outer Piedmont Ecoregion (Griffith et al., 2001). Considered the non-mountainous portion of the old Appalachian Highland by physiographers, the northeast- southwest trending Piedmont ecoregion comprises a transitional area between the mostly mountainous ecoregions of the Appalachians to the northwest, and the relatively flat coastal plain to the southeast. It is a complex mosaic of Precambrian and Paleozoic metamorphic and igneous rocks with moderately dissected irregular plains and some hills. The soils tend to consist of a finer texture than is commonly found in coastal plain regions. Once largely cultivated, much of this region has reverted to pine and hardwood woodlands, and, more recently, spreading urban- and suburbanization. The Southern Outer Piedmont ecoregion has lower elevations, less relief, and less precipitation than the Southern Inner Piedmont, which occurs further to the north. Loblolly-shortleaf pine is the major forest type, with less oak-hickory and oak-pine than in Southern Inner Piedmont. Gneiss, schist and granite are the dominant rock types, covered with deep saprolite and mostly red, clayey subsoils. The majority of soils are Kanhapludults. The southern boundary of the ecoregion occurs at the Fall Line, where unconsolidated coastal plain sediments are deposited over the Piedmont metamorphic and igneous rocks. Due to the topography in this region, streams in the Shoal Creek Watershed are described as high gradient (riffle/run prevalent) streams. The average annual precipitation in the region of the watershed is 49.29 inches per year based on data from a weather station in Experiment, Georgia (SRCC, 2007). March is the wettest month of the year, receiving an average of 5.61 inches of rainfall.
3.3 Environmentally Sensitive Areas Shoal Creek and its tributaries are arguably the most environmentally sensitive areas within the Shoal Creek service area. Most of the upland areas are developed. There are no natural parklands or recreational lakes within the service area. Table 3-1 identifies species occurring in Spalding County that are listed as Threatened or Endangered, or of Special Concern by the Federal and State governments (GA DNR, 2009). These species may potentially occur in the Shoal Creek watershed. The Georgia Department of Natural Resources, Wildlife Resources Division has a recorded occurrence of the Alexander Rock Aster, a rare plant, occurring in USGS quarter quad Griffin South, GA NE, which includes a large portion of the Shoal Creek service area. There is also a recorded occurrence of the Oval Pigtoe, an endangered mollusk, in quarter quad Brooks, GA SE, which includes the most western tip of the Shoal Creek service area. No natural communities are listed in Spalding County. National Wetland Inventory (NWI) Wetlands are depicted in Figure 3-5. There are a few, isolated wetlands within the service area, as well as linear, floodplain wetlands along portions of Shoal Creek, Heads Creek, and Wasp Creek. These wetland areas should not be subject to alteration or degradation. Protection for these areas is provided by the State of Georgia through “Criteria for Wetlands Protection,” which describes for local governments minimal considerations for wetlands protection in the land use planning process. According to the Federal Emergency Management Agency flood maps, floodplains are located in the Shoal Creek service area, primarily along Shoal Creek and Heads Creek and their tributaries. Within the City of Griffin, these areas are managed by Griffin’s Floodplain Management Ordinance, which emphasizes protection of human property.
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Table 3-1. Listed Species in Spalding County
Federal State Species Common Name Status Status
Invertebrate Alasmidonta triangulata Southern Elktoe E Anodontoides radiatus Rayed Creekshell T Elliptio purpurella Inflated Spike T Hamiota subangulata Shinyrayed Pocketbook E E Medionidus penicillatus Gulf Moccasinshell E E Pleurobema pyriforme Oval Pigtoe E E Quincuncina infucata Sculptured Pigtoe S3 Utterbackia peggyae Florida Floater S2 Fish Cyprinella xaenura Altamaha Shiner T Notropis hypsilepis Highscale Shiner R Plants Aster avitus Alexander Rock Aster S3 E- Listed as endangered T- Listed as threatened S2- Imperiled in state because of rarity (6 to 20 occurrences) S3- Rare or uncommon in state (on the order of 21 to 100 occurrences)
11 Shoal Creek Watershed Assessment November 2009
City Limits Existing Service Areas 305b/303d Assess ed Streams Water Cabin Creek Not Supporting NWI Wetlands Potato Creek SupportingTroublesome Creek Shoal Creek Not Assessed Heads Creek
Sho al C reek
k
e H e r o k n C k e e t e y e a e l r
r B F C e
C s e
n i C
sp k r l a e E e W k
Cabin Creek and Shoal Creek Wastewater Service Area 0120.5 National Wetlands Inventory (NWI) Wetland Areas Kilometers
NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 0120.5 Map produced 07-30-2009 - P. Cada Miles
Figure 3-5. National Wetland Inventory Wetlands in Shoal Creek Service Area
12 Shoal Creek Watershed Assessment November 2009
3.4 303(d) Listed Waterbodies The EPD, in compliance with the Clean Water Act, has developed a listing of water quality impaired streams in Georgia. The listing is subdivided into several categories: streams that do not support their designated use, reservoirs and lakes not fully supporting their designated use, and estuaries not fully supporting their designated use. Streams are color coded according to their designations on Figure 3-2. Shoal Creek and its tributaries were not assessed, and are therefore not listed for any impairment on the Georgia EPD 2008 303(d) list; however, Wasp Creek, which is in the Shoal Creek service area, is listed for not supporting its designated use of fishing. The criterion violated is Biota. The 303(d) listing attributes the impairments to nonpoint sources. A Total Maximum Daily Load (TMDL) for five miles of Wasp Creek was finalized in 2008. The listed area is from the Wasp Creek headwaters to its confluence with Little Wasp Creek; some of which is within the Shoal Creek service area. The TMDL for Wasp Creek is summarized in Table 3-2.
Table 3-2. TMDL for Wasp Creek
Load Allocation Margin of Waste Load Allocation Percent Parameter (LA) Safety TMDL (WLA) Reduction Non-Point (MOS) Biota (Sediment) 0.3 tons/yr 37.1 tons/yr implicit 5.5 tons/day 0% 2008 TMDL report
The TMDL is the total amount of pollutant that can be assimilated by the receiving water body while achieving water quality standards. A TMDL is comprised of the sum of individual waste load allocations (WLAs) for point sources, and load allocations (LAs) for both non-point sources and natural background levels for a given watershed. In addition, the TMDL must include a margin of safety (MOS), either implicitly or explicitly, that accounts for the uncertainty in the relation between pollutant loads and the quality of the receiving water body. Conceptually, this definition is denoted by the equation: TMDL = Σ WLAs + Σ LAs + MOS
3.4.1 Biota (sediment) The Biota Impacted designation indicates that studies have shown a modification of the biological community; more specifically, fish. During 1998-2003, the Department of Natural Resources (DNR) Wildlife Resources Division (WRD) conducted studies of fish populations in the Flint River Basin. WRD used the Index of Biotic Integrity (IBI) and modified Index of Well-Being (IWB) to identify affected fish populations. The IBI and IWB values were used to classify the populations as Excellent, Good, Fair, Poor, or Very Poor. Stream segments with fish populations rated as Poor or Very Poor were listed as Biota Impacted, and were included in the partially supporting or not supporting list. The Wasp Creek stream segment was rated as Very Poor, and placed on the 303(d) list as partially supporting its designated use. The Biota Impacted designation indicates that studies have shown a significant modification of the biological community. The TMDL for Wasp Creek was completed in 2008. The Flint River Basin, along with the Chattahoochee River Basin, were the basins of focused monitoring in 2000 and will again receive focused monitoring in 2010. One goal of the focused basin monitoring is to continue to monitor 303(d) listed waters. Therefore, additional monitoring of these streams will be
13 Shoal Creek Watershed Assessment November 2009 initiated as appropriate during the next monitoring cycle to determine if there has been improvement in the biological communities. INITIAL TMDL IMPLEMENTATION PLAN SEDIMENT (BIOTA IMPACTED) 2008 The 2008 Initial TMDL Implementation Plan includes a list of best management practices and provides for an initial implementation demonstration project to address one of the major sources of pollutants identified in this TMDL while State and/or local agencies work with local stakeholders to develop a revised TMDL implementation plan. It also includes a process whereby GA EPD and/or Regional Development Centers (RDCs) or other GA EPD contractors will develop expanded plans.
3.4.2 Downstream Impairment Downstream of the service area, Wildcat Creek and Heads Creek are also listed for impairment on the EPD 2008 303(d) list. The entire length of Wildcat Creek is listed due to excessive levels of fecal coliform bacteria and Heads Creek from the Heads Creek reservoir downstream to the confluence with Wildcat Creek is listed for impaired biota due to sediment, for its designated use of fishing. EPD completed TMDLs in 2003 for both of these streams to address the water q uality issues. Since Wildc at Creek receives flow from only tw o tributaries, Shoal and Heads, water q uality issues in the Shoal Creek watershed may impact Wildcat Creek.
3.5 Significant Fa cilities and Activit ies
3.5.1 Water Supplies There are no reservoirs within the Shoal Creek service area, but the Heads Creek Reservoir, a City of Griffin water supply, receives inflow from the headwaters of Heads Creek, which is within the Shoal Creek service area. The Shoal Creek service area is roughly 1.5 miles east (and upstream) of the reservoir intake. The intake is just above the Central Georgia Railroad crossing. Wasp Creek drains to Potato Creek, which is a water supply for the City of Thomaston in Upson County. The Shoal Creek service area southern boundary is approximately 7 miles upstream of the Potato Creek- Wasp Creek confluence. The City of Thomaston has three intakes on Potato Creek: the first is just below Red River, the second is just below Drake Creek, and the third is just below Ten Mile Creek. The City of Griffin has two water supply intakes along the Flint River. One is 20 miles downstream of the service area, just upstream of Still Branch, which is the first reservoir intake downstream of the service area. The other intake is upstream of the Horton Creek confluence, which is upstream of the Wildcat Creek confluence and, therefore, not affected by the service area.
3.5.2 Wastewater and Stormwater Facilities One NPDES permitted facility is associated with the Shoal Creek service area: the Shoal Creek Blanton Mill Land Application Site (Figure 3-2). The Shoal Creek WWTP pumps treated municipal wastewater to the Blanton Mill Land Application Site, located downstream of the Wildcat Creek confluence, and outside of the service area. According to available location information in EPA databases, no NPDES permitted industrial facilities occur within the service area. Although the service area is sewered, some residential properties continue to use onsite wastewater systems. The locations of septic systems, as provided by the Spalding County Health Department, are depicted on Figure 3-2. Griffin was the first local government in the state of Georgia to set up a stormwater utility. The utility charges a fee for residences and commercial developments, which funds the treatment and control of
14 Shoal Creek Watershed Assessment November 2009 stormwater runoff before it is discharged to surface water. Stormwater structures under political jurisdiction are identified on Figure 3-2. The City of Griffin stormwater is permitted under the Georgia Phase II NPDES General Permit. The City published their Stormwater Master Plan in 2003, which can be accessed through the City’s stormwater website: http://www.griffinstorm.com/sw/Links/StormwaterUtility/MasterPlan/MasterPlanIndex.htm The Master Plan includes an NPDES Stormwater Permitting Phase II Action Plan to address Phase II regulatory requirements. Future land disturbing activities will likely occur due to construction, and these activities will be regulated by the City’s erosion and sediment control ordinance. There is currently one active construction site in the Shoal Creek Watershed with a Notice of Intent (NOI). This is for a parking lot for the University of Georgia Griffin Campus. There are two innovative detention ponds used to treat stormwater in the Shoal Creek service area: the North Griffin Regional Detention Pond and Oakview Detention Pond. The detention ponds were designed to improve water quality and control flooding in urbanized areas by including construction of rock dams, wetlands, and outlet devices to remove pollutants.
3.5.3 Agricultural Operations There are no large agriculture operations existing within the Shoal Creek Watershed, such as commercial forestry or confined animal feeding operations (CAFOs). However, timber harvesting by private, non- industrial landowners occurs annually, and some of these activities may take place within the watershed. The Georgia Experimental Farms is located in the Shoal Creek Watershed, along the By-Pass. Small horse and cattle farms exist outside city limits as well as hay and row crop operations. No agricultural land application sites exist in the watershed, according to the Georgia EPD Land Application Site (LAS) GIS database, last updated in 1999.
3.5.4 Solid and Hazardous Waste and Toxic Releases According to the June 2009 EPA Envirofacts GIS Database, no facilities in the Shoal Creek Watershed are listed by EPA as Comprehensive Environmental Response, Compensation and Liability (CERCLA) sites, or Resource Conservation and Recovery Act (RCRA) sites. Two Toxic Release Inventory (TRI) sites occur in the Shoal Creek service area, AEP Industries and LaFarge Griffin Concrete Plant. One landfill is located within the Shoal Creek Watershed according to the Georgia EPD landfill GIS database last updated in 1999. This facility is the Shoal Creek Landfill located near Shoal Creek, upstream of the Shoal Creek WWTP and within the service area. The municipal phase of this landfill is closed, and it is currently used as a construction and demolition landfill only. No other municipal or hazardous waste facilities or industries exist within the service area or watershed according to the Georgia Hazardous Site Inventory, last updated in 1999 and available from the Georgia GIS Data Clearinghouse. The Shoal Creek Landfill and TRI sites are shown on Figure 3-2.
15 Shoal Creek Watershed Assessment November 2009
4 Data Collection
4.1 Water Quality Data
4.1.1 Monitoring Stations The City has conducted a comprehensive program of water quality sampling in the Shoal Creek watershed for several years. Monitoring Stations are depicted in Figure 4-1 and listed in Table 4-1. In the summer of 2001, a monitoring program was initiated that included 14 weeks of both in-situ and laboratory grab samples in the first year. Sampling continued thereafter, and this sampling has been used to establish current levels of water quality and detect any changes to water quality over time. When the monitoring program was initiated, there were 10 sample sites in the service area that were used to obtain in-situ and grab samples (SC1 through SC 8, HC1, and HC2). Several of these stations have been revised to better reflect the needs of the monitoring program and the conditions of the watershed. Stations SC0 and SC10 were added in March 2005, and Stations HC1, SC1, SC3, SC4, SC6, SC7, and SC8 were decommissioned in the fall of 2004. This assessment only examines data through July of 2009. However, the Georgia EPD has recommended some changes to monitoring stations that will be reflected in the long term monitoring plan for the Shoal Creek Watershed Protection Plan. In the future, HC2 will no longer be used, and a new station HC3 will be added near the service area boundary along a Heads Creek tributary. Sampling will also be conducted at a new station WC1 along Wasp Creek. The drainage areas of the sample locations are representative of the major land uses and the 303(d)-listed waterbodies in the service area. Since no future service area expansion is proposed, the monitoring station selection considered the existing service area only. Flow in the Shoal Creek watershed leaves and reenters Griffin jurisdiction in several areas. SC0, SC5 and SC10 all monitor water quality leaving the Griffin political boundaries. Because Wildcat Creek receives flow from Shoal Creek, and also Heads Creek, water quality issues identified by this Shoal Creek Watershed Assessment have some impact on downstream areas. SC0 and SC5 are the most downstream stations, which could be used to reflect input from Shoal Creek watershed into Wildcat Creek. Any water quality impacts by future changes to land use or areas of new growth will be reflected in these most downstream stations as well. SC2 is located in Shoal Creek at North Pine Hill Road on the west side of the City. This station best serves to monitor the water quality leaving the experimental farm area. Heads Creek water quality will be monitored at HC3. This station is located near the service area boundary along a Heads Creek tributary and measures the water quality that is leaving the City of Griffin. Wasp Creek water quality will be monitored at WC1. This station is located near the service area boundary along Wasp Creek and will measure the water quality that is leaving the City of Griffin. The City of Griffin has also collected water quality reference data, since March 2005, from station REF-1 at the location shown in Figure 4-2. This site is located within the lower Piedmont eco-region Stream gage data were obtained from USGS station 02344478 (Shoal Creek at Shoal Creek Road, near Griffin, GA) and daily rainfall data were obtained from the Georgia Automated Environmental Monitoring Network (GAEMN) University of Georgia, Georgia Experiment Station weather station. Flow data, discharge data, and rainfall data are included in Appendix A.
16 Shoal Creek Watershed Assessment November 2009
Table 4-1. Monitoring Stations
Site ID Sampling Start Sampling End Description Site Selection Rationale (Griffin ID) Date Date
SC0 – Shoal Shoal Creek west of Measures water quality leaving Creek the Griffin Country March 17, 2005 Present Shoal Creek Lake area and the (WQ38) Club Griffin jurisdiction
SC1 – Shoal Shoal Creek west of Measures Water Quality Leaving Creek the Griffin Country July 31, 2001 Sept. 22, 2004 Griffin Jurisdiction (WQ24) Club
SC2 – Shoal Measures Water Quality Re- Shoal Creek @ North Creek July 31, 2001 Present Entering Griffin from the Pine Hill Road (WQ25) Experiment Station Farms
SC3 – Shoal Measures Water Quality Leaving Shoal Creek @ Creek July 31, 2001 Sept. 22, 2004 Griffin Jurisdiction and Entering Highway 19/41 Bypass (WQ26) Experiment Station Farms
SC4 – Shoal Shoal Creek Main Measures Water Quality Leaving Creek Stem Tributary @ July 31, 2001 Sept. 22, 2004 Griffin Jurisdiction and Entering (WQ27) Highway 19/41 Bypass Experiment Station Farms
SC5 – Shoal Southwest Tributary @ Measures Water Quality Re- Creek Southwest Corner of July 31, 2001 Present Entering from Spalding County (WQ28) Griffin Country Club and Leaving Griffin Jurisdiction
SC6 – Shoal Measures Water Quality Leaving Southwest Tributary @ Creek July 31, 2001 Sept. 22, 2004 Griffin Jurisdiction and Entering South Pine Hill Road (WQ29) Spalding County
SC7 – Shoal Measures Combined Southwest Tributary @ Creek July 31, 2001 Sept. 22, 2004 Griffin/Spalding County Water Carver Road (WQ30) Quality from Headwaters Drainage
SC8 – Shoal Shoal Creek @ Measures Water Quality from Creek July 31, 2001 Sept. 22, 2004 Lyndon Road Downtown Headwaters Area (WQ31)
Measures water quality from Shoal SC10 – Shoal Shoal Creek @ Creek headwater originating in Creek March 17, 2005 Present Highway 19/41 Griffin and entering Experiment (WQ39) Station Farms
HC1 – Heads Heads Creek Tributary Measures Water Quality Leaving Creek July 31, 2001 Sept. 22, 2004 @ Rosewood Road Griffin Jurisdiction (WQ32)
HC2 – Heads Heads Creek Tributary Measures Water Quality Leaving Creek July 31, 2001 July 6, 2009 @ Lucky Street Griffin Jurisdiction (WQ33)
HC3 – Heads Heads Creek Tributary Measures Water Quality Leaving Creek near service area Future Future Griffin Jurisdiction (WQ41) boundary
WC1 – Wasp Wasp Creek near Measures Water Quality Leaving Future Future (WQ42) service area boundary Shoal Creek Service Area
REF-1 Brittens Creek, March 17, 2005 present Water quality reference site (WQ 40) Meriwether County
17 Shoal Creek Watershed Assessment November 2009
Shoal Creek WWTP Cabin Creek Service Area
Stream Gage Potato Creek Service Area
Current Sample Sites Shoal Creek Service Area Cabin Creek Watershed Previous Sample Sites Heads, Shoal, and Wasp Creeks Watersheds City Limits Potato Creek Watershed Streams Other Watersheds Major Roads
HC 3 DOBBINS MILL RD
S R 9 HC 1 2 HC 2
N
E
X
P
R
E S SC 3 S k W e Cre A in USGS 20344478 Y SC 10 Cab SC 1 SC 2 SC 8 SC 0
Creek Shoal
Shoal Creek W TAYL OR ST SC 4 E TAYLOR ST
WWTP H 6 W
Y 1 T
R 1 S 9 S
/
4
1
L
L
I
H
SC 5 S
Is o n B SC 6 ranc SC 7 h
D R N Was O RD p C L reek U N B SO E M 19/41 WY Z
A H LI IL W H o k n e e e y r B ee C C s r in ee lk WC 1 k E
00.5 12 Shoal Creek Sample Site Locations Kilometers NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 010.5 2 Map produced 10-10-2009 - P. Cada Miles
Figure 4-1. Water Quality Monitoring Stations
18 Shoal Creek Watershed Assessment November 2009
F la S t Clayton County k Fulton County a M ree Legend C nd o C r y rn es K e C in at S N g P e e re k a C k h k d k ek e s re e e (! Monitoringo Station r e h e e e Existingo Service Areasr k r r a n C C C t C l r u C e C k ln h e e ee a c County BoundariesL r Cabin Creek k r r e k r Cr W i e i k a n e a ug B e e Co e k C e k k e Streams Potato Creekr r e C r e C C r g l e C y a n r o I e i h nd City Limits Shoala Creek r Ga S k m e G y ia P W C n h p re C c ek o e C o Henry County r n Rock Branch e k e r r l e a e s To k r F C e e B l l Fayette County a k y w t a A n o C C n a a h r l r t k i iv e S i e ee g l k o e r l e c C a e k r u k h ea e B R S Ke r g C k i C C ve re r e ek e Coweta County e r ck e r o k C k h d e c d re s n d C a Ha a e r in B L e W P i H e n t L h e e i D a t t C C P l e Spalding County a t e a bi l d r n e e C W O S re y a e Creek hoa ek h k k dcat Shoa l B Wil l Creek Cr it C e r e r ek a e e B n O Ga k uc c b I a le B r s k h ra o C k nch e n re v B e C i ra k r R F n e W c k t la h e e n t e a r k i C C l k r s the F re an W e e p P e k r L h C o i C k r t e e e n e s r e g O n C i k r a B e k v k l r a C E a e T n B r S e u c h e L r o n h a k e ls w p C k i re e i k e s e k re C REF-1 C C h r e Ha r rc rdin C e (! i E e reek B e l k k k i k n e s re B l C k Pike County k il ee r e r a M e C e Littl n c
Meriwether County Cr h P
o o k t K ee w ek r e a C r t e ut Still Branch d C n B la o aln ull C e Go n r P W ree e k C T l h C r h c e r Lamar County r n h ek e e e a c re k e e r n C a n m k B k r ai s Cree B t i Pappy n l s s ou e t M N m h i ig o C S n S r r reek J P K r e Rose C o p i a un r s e c d in k k C g C S s re u e Can C B T r C k e Cr e ll eek re a e iv ree e s n e a k in m k n M r C k C Rive h i r i l ed e l r e R l c e e k C e C k e k k an
r M r k k e e e r e k r e e e e r e re B c e e C e C C C k r F k k r uc g r
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B k C t e T n B k e t a r i C l e r City of Griffin Water Quality Reference Station 0512.5 c 0
e n l r eo n L s h e a g I d Pi w Kilometers r n a NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet o Be C c
c T Map produced 12-09-2008 - H. Fisher k t h e
s re 0482 f C i a ud Harris County M Talbot County Upson CountyMiles w C S
Figure 4-2. City of Griffin Water Quality Reference Monitoring Station
19 Shoal Creek Watershed Assessment November 2009
4.1.2 Monitoring History Initial Shoal Creek Watershed sampling took place from July 31, 2001 to November 27, 2001. The City started its long-term monitoring in August of 2003 with semi-annual measurements in 2004 and then quarterly sampling beginning in 2005, with two wet and two dry weather samples collected each year. This schedule ensures that all water quality parameters (in-situ and laboratory grab samples) are collected, captures critical conditions such as low flow and high temperature, confirms that the water quality standards are being met, and can be used to demonstrate effects of stormwater during high flow conditions or non-storm related stressors. A minimum of three dry weather samples, one wet weather sample, and one w et-weather comp osite sample is suggested by Georgia EPD Guidance (GA DNR, 2005a). The City has performed more than the suggested number of dry and wet weather samples. A wet-weather composite sample will be performed in fiscal year 2010-2011. Since the program’s initiation, the City of Griffin conducted a total of 41 sampling events between July 2001 and July 2009. These sampling events monitored the majority of water quality and biological parameters recommended in EPD Guidance. In addition to regular water quality analysis, the City also conducted pollutant scanning and sediment sampling for several additional constituents. The Shoal Creek Monitoring Plan (May 2009) provides details on sampling methods, parameters, frequency, and detection limits. Table 4-2 briefly outlines the historical sampling that has occurred in the watershed. Table 4-3 provides the details of each sampling event. Some parameters were measured at site (in-situ) and others were measured in a laboratory from samples collected at site. Laboratory analyses were performed by either the City of Griffin or Analytical Services, Inc. Sampling procedures and techniques are detailed in the Shoal Creek Monitoring Plan.
Table 4-2. Summary of Sampling Conducted in the Shoal Creek Watershed Since 2001
Sample Type Shoal Creek Guidance
Total amount of Sample Events 41 4
Wet Weather Events 18 1
Dry Weather Events 23 3
In-Situ Sampling 39 -
Fecal Coliform Sampling 39 samples 2 geometric means
Laboratory Grab Sampling 25 -
Priority Pollutants Sampling 1 Not required
Sediments Sampling 2 Not required
Wet Weather Composite Sample 0 1
Table 4-3. Sample Events
Sample Event Fecal Laboratory Priority In-Situ Sediments Date Classification Coliform Grab Pollutants
7/31/01 Wet All Sites All Sites
8/7/01 Dry All Sites All Sites
20 Shoal Creek Watershed Assessment November 2009
Sample Event Fecal Laboratory Priority In-Situ Sediments Date Classification Coliform Grab Pollutants
8/14/01 Wet All Sites All Sites All Sites
8/21/01 Dry All Sites All Sites All Sites
7/31/01 Wet All Sites All Sites
8/7/2001 Dry All Sites All Sites
8/14/2001 Wet All Sites All Sites
8/21/2001 Dry All Sites All Sites
8/28/01 Dry All Sites All Sites
9/4/01 Wet All Sites All Sites All Sites SC1, SC5
9/11/01 Wet All Sites All Sites
9/17/01 Dry All Sites All Sites
9/25/01 Wet All Sites All Sites
10/2/01 Dry All Sites All Sites All Sites
10/9/01 Dry All Sites All Sites
10/16/01 Dry All Sites All Sites
10/23/01 Dry All Sites All Sites
10/30/01 Dry All Sites
11/6/01 Dry All Sites All Sites
11/27/01 Wet All Sites
9/2/03 Dry All Sites All Sites All Sites All Sites
2/27/04 Wet All Sites All Sites All Sites
9/22/04 Dry All Sites All Sites
3/17/05 Wet All Sites All Sites All Sites
5/25/05 Dry All Sites All Sites All Sites
8/25/05 Wet All Sites All Sites All Sites
11/7/05 Dry All Sites All Sites All Sites
2/8/06 Wet All Sites All Sites All Sites
5/23/06 Dry All Sites All Sites All Sites
8/21/06 Wet All Sites All Sites All Sites
11/13/06 Dry All Sites All Sites All Sites
2/5/07 Dry All Sites All Sites All Sites
6/13/07 Wet All Sites All Sites All Sites
8/7/07 Dry All Sites All Sites All Sites
21 Shoal Creek Watershed Assessment November 2009
Sample Event Fecal Laboratory Priority In-Situ Sediments Date Classification Coliform Grab Pollutants
11/15/07 Wet All Sites All Sites All Sites
3/26/08 Dry All Sites All Sites All Sites
7/14/08 Wet All Sites All Sites All Sites
8/21/08 Dry All Sites All Sites All Sites
12/10/08 Wet All Sites All Sites All Sites
2/23/09 Dry All Sites All Sites All Sites
7/6/09 Wet All Sites All Sites All Sites
8/11/09 Dry All Sites All Sites All Sites Note: “All sites” includes all sites being monitored as of the sample date. 7/31/01-09/22/2004: Sites SC1 through SC9, HC1 & HC2 3/17/2005-0 8/11/2009: Sites SC0, SC2, SC5, SC10, HC1 & HC2
In fiscal year 2010- 2011, one composite sample wil l be p erformed at SC10 that covers the complete hydrogra ph during a wet weather event. Also beginning in fiscal year 2010-2011 , the City w ill begin sampling fecal coliform between May and October in order to determine the geometric mean of bacteria in the watershed. E. coli will be sampled once per y ear beginning in fiscal year 2 010-2011.
The City will begin sampling hardness, as calcium c arbo nate (CaCO3), in fiscal year 2010-2011. This sampling w ill allow the City to c alculate dissolved metals concentrations based on the total metal concentrations sam pled for cadmium, co pper, lead, and zinc. The City may also decide to continue priority pollutant scans and sediment sampling at their discretion.
4.2 Land Use Data Land use is examined based on parcel data from the City of Griffin and Spalding County, and impervious coverage data from University of Georg ia’s Natural Resources Spatial Analysis Lab (NRSAL) Georgia Land Use Trends (GLUT). Land use data can be used to identify areas of increased impervious runoff, or areas that may be contributing particular pollutants, which can then be associated with the hydrologic and environmental char acteristics of the cor responding d rainage areas. Table 4-4 lists some basic land use classes and the average percent imp ervious for each, adapted from Technical Report 55 (TR-55), developed by the Natural Resource Conservation Service (USDA, 1986).
22 Shoal Creek Watershed Assessment November 2009
Table 4-4. Land Use Classification
Avg. Land Use Description Imperviousness Residentia l (town houses) 1/8 acre or less average lot size 65% Residential 1/4 acre average lot size 38% Residential 1/3 acre average lot s ize 30% Residential 1/2 acre average lot s ize 25% Residential 1 acre average lot si ze 20% Residential 2 acre average lot size 12% Commercial Shopping Centers/Offices/Institutional 85% Industrial Factories /Warehouses /etc. 72% Open Space Lawns/Golf Courses/etc. 0% Forests/Heavy Tree Canopy and Ground Wooded 0% Cover
Mapped land use for the subwatersheds draining to each Shoal Creek monitoring station may be found in Figure 4-3. A Future Land Use Map that includes City of Griffin and Spalding County data is shown in Figure 4-4.
23 Shoal Creek Watershed Assessment November 2009
City of Griffin LU/LC Sample Site
l Shoal Creek Subwatershed " " a " v. ict A B n "A" "B" C ev. . . " De Dev. d. " d. " tio Resid l D l l City Limits si si sid sid. sid ia ia a e e titu rc r ss Distr s Re Re Re sity e enti e In y n Water ity R ity R ty y e m id sin s s sit si D m Indust u n n n n sit e e n m Stream De De d Res D D De diu d Co ned e h h w w w e n n o o o n n L L L Me n Pla Wastewater Service Areas Central B Hig Hig Pla Pla Cabin Creek Service Area Spalding County LU/LC Potato Creek Service Area Shoal Creek Service Area l l l a a na nti erci tio e m tu m facturing sid o sti e . and Resid.C /In R g e A Manu ffic O
HC 3 HC 1 HC 2
SC 3 SC 10 SC 1 SC 2
SC 0 SC 8
SC 4
SC 5
SC 6 SC 7
WC 1
Shoal Creek - Existing Land Use for 021 Sample Site Subwatersheds Kilometers
NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 021 Map produced 09-22-2009 - P. Cada Miles
Figure 4-3. Existing Land Use and Sampling Site Subwatersheds
24 Shoal Creek Watershed Assessment November 2009
City of Griffin Predicted LU/LC Sample Site
Shoal Creek Subwatershed . b l l l n d id. ss se a a e s sid e ion cia u ri n tio e Hu o Util. e n sit er o st va City Limits Resid. ssional sin n h u uti r m./ y R y e w a m re d tit it f Bu to r m In m o T ns o nsity R d e Co I onse Water e Pr o wn ic l ./C o o a /C p /Undevelop rh D n rial/Wa s t w D ice o Off st n o ff b io u Stream L O h g d acan High Densit n /Recr. Tra V Re I k Medium Dens eig t Wastewater Service Areas N Par igh L Cabin Creek Service Area Spalding County Predicted LU/LC Potato Creek Service Area Shoal Creek Service Area y l d n k id. r re ia ial e til. r s st u e e lt erc str atio cu u e For ri m d m./U cr ity Resid. m In m Netwo s l, Plann o e nsity R Ag a Re c e Co ri /C a st p. & u s ks Sp w D d n r n o In ra e L Med. Den T Pa Op
HC 3 HC 1 HC 2
SC 3 SC 10 SC 1 SC 2 SC 0 SC 8
SC 4 SC 5
SC 6 SC 7
WC 1
Shoal Creek - Predicted Future Land Use for 021 Sample Site Subwatersheds Kilometers
NAD_1983_StatePlane_Georgia_West_FIPS_1002_Feet 021 Map produced 09-22-2009 - P. Cada Miles
Figure 4-4. Future Land Use and Sampling Site Subwatersheds
25 Shoal Creek Watershed Assessment November 2009
4.3 Biological/Habitat Data Monitoring the biological component of the waterways within the watershed is integral, along with assessing water quality, in order to determine current condition or any impairment(s) that may exist. Biological criteria are used to assess the integrity of the watershed and are based on the premise that an aquatic community’s structure and function provide critical information about the quality of surface waters. The City of Griffin has conducted three Biological Assessments to date (2000, 2004/2005, and 2008/2009).
4.3.1 2000 Biological/Habitat Data As part of the City of Griffin watershed monitoring program, the City assesses conditions of biotic integrity and habitat within the three main watersheds draining Griffin (Cabin Creek, Potato Creek, and Shoal Creek). An analysis of habitat, macroinvertebrate communities, and fish communities was conducted by CCR Environmental, Inc. of Atlanta, Georgia during the summer of 2000. Conditions of biotic integrity were assessed at three monitoring stations located in the three major Griffin watersheds. The Shoal Creek monitoring station was located on Shoal Creek at North Pine Hill Road, and corresponds to water quality monitoring station SC2. The water quality reference site in Meriwether County (Figure 4-2) was also used as a biological reference site for habitat and macroinvertebrate assessments. Habitat assessments were conducted in accordance with the Georgia DNR protocol using the Habitat Assessment Worksheet for riffle/run habitat (GA DNR 1999 [draft]). At each site, all individual habitat parameters were scored, and a total score was obtained. The habitat scores were then used to derive an ecological condition rating: • Optimal - meets natural expectations, • Suboptimal - less than desirable but satisfies expectations in most areas, • Marginal - moderate levels of degradation with severe degradation at frequent intervals in area, and • Poor - substantially altered with severe degradation.
The habitat score at each monitoring station was compared to the habitat score at the reference site to classify each site on the basis of its similarity to expected conditions: comparable to reference, similar to reference, partially similar to reference, or dissimilar to reference. The benthic macroinvertebrate community was assessed under a modified Georgia Bioassessment Protocol (GBP) (GA DNR, 1999 [draft]). Percent comparability of each site's total GBP score to the reference site's total GBP score was used to determine ecological condition of the study site: Very Good, Good, Fair, Poor, or Very Poor. The fish community was assessed using the Index of Biotic Integrity (IBI) criteria developed for fish communities in the Piedmont Ecoregion of Georgia (GA DNR, 2000 [draft]). IBI scores are categorized into five integrity or quality classes: Excellent, Good, Fair, Poor, and Very Poor. Habitat assessments and benthic macroinvertebrate collections at all sites were conducted on May 9, 2000; fish were collected at the three monitoring stations on May 11, 2000. The 2000 Biological Assessment report, including methodologies and results, is included in Appendix B.
4.3.2 2004/2005 Biological/Habitat Data Biological monitoring stations were revised after the initial study in 2000. The three initial monitoring stations were replaced by 15 stations within and around the city limits, representing the three main watersheds. The stations occurring within the Shoal Creek watershed are sites that are also used for water
26 Shoal Creek Watershed Assessment November 2009 quality sampling, SC0, SC2, SC5, SC10, and HC2, as shown in Figure 4-1. The location of these monitoring stations allows the City to evaluate the effect of water quality on the biological integrity of Shoal Creek and Heads Creek. Macroinvertebrate and habitat sampling were conducted at each of these sites. Fish community sampling was only conducted at stations SC2 and SC5. These sites were chosen for fish assessment because they receive the greatest surface runoff from the service area compared to other sites. Tetra Tech conducted biological monitoring in 2004/2005. The sites were sampled for benthic macroinvertebrates and physical habitat in November 2004. Sites SC2 and SC3 were revisited, as well as the reference site in Meriwether County, Georgia, to sample fish in January 2005. The reference site is the same as that used for water quality sampling (Figure 4-2). Benthic macroinvertebrates were sampled following revised protocols developed by GA EPD (2004 [draft]), and the data analyzed using the Benthic Macroinvertebrate Index (BMI) developed and calibrated by Columbus State University (Gore et al. 2004 [draft]) for streams in the Southern Outer Piedmont Ecoregion. Fish were sampled and the data analyzed using the IBI criteria developed by Georgia DNR (2000 [draft]) for streams in the Georgia Piedmont Ecoregion. Sampling methodology and results of the 2004/2005 biological assessment are included in the 2005 Biological Assessment in Appendix B.
4.3.3 2008/2009 Biological/Habitat Data CCR Environmental, Inc. conducted biological monitoring in 2008/2009. Monitoring was conducted using updated GA DNR protocols for benthic macroinvertebrates (GA DNR 2007) and fish (GA DNR, 2005b). The monitoring stations used in 2008/2009 are the same as those used in 2004/2005, however the reference site in Meriwether County, GA was not used. This reference site was deemed unnecessary since the fish and macroinvertebrate indices already incorporate established ecoregional reference site data into their ratings. Fish sampling was conducted at sites SC2 and SC5 in August 2008. Habitat assessments and benthic macroinvertebrate collections were performed in January and February 2009. Sampling methodology and results of the 2008/2009 biological assessment are included in the 2009 Biological Assessment in Appendix B. Per a request from Georgia EPD, monitoring station HC3 (shown on Figure 4-1) will be added as a site for future biological monitoring and monitoring will be discontinued at station HC2. However, these changes and are not factored into this assessment.
4.4 Other Monitoring Data
4.4.1 Geomorphic Assessment The City of Griffin conducted a preliminary geomorphic assessment prior to 2001 that focused on locating degraded stream segments in the upper reaches of the watershed. All streams within the City were generally classified based on the following categories: • Restoration – Highly degraded, acceptable for full streambed and streambank restoration. • Restoration or Enhancement – Moderately degraded, acceptable for restoration of streambank or streambed. • Enhancement – Slightly degraded, acceptable for enhancement of aquatic habitat. • Preservation – Intact streambed or riparian corridor acceptable for permanent preservation.
27 Shoal Creek Watershed Assessment November 2009
The existing condition of streams and associated riparian corridors within the City were classified as highly degraded resulting from streams having been channelized and severely entrenched by high velocity runoff. Streams within the city limits were visually assessed and preliminarily categorized for enhancement, restoration and preservation and were incorporated into the City’s GIS database according to restoration potential (Philips et al., 2001). In 2004, the city performed additional geomorphology work on the Shoal Creek watershed, above the Griffin Country Club Lake. At least 120 sites were assessed. Impacts from urban, upland, and natural activities were described for each site, as well as suspected sediment source hotspots and other potential influences on the stream channels. This assessment, conducted by Tetra Tech, included written characterizations of the stream, maps illustrating assessment results in terms of channel erosion activity, and photographs of assessment sites. The assessment was carried out by a fluvial geomorphologist walking on the stream bed and conducting Rapid Geomorphic Assessments (RGAs). The 2004 Shoal Creek Geomorphic Assessment is included as Appendix C, entitled Stream Channel Stability Assessment of the Shoal Creek Watershed. The 2004 Geomorphic Assessment attributed sediment loadings in Shoal Creek to sources both in the channel and in the adjacent uplands. Several channel erosion hot spots were identified in the main stem and in some tributaries of Shoal Creek, where the most severe erosion was actively occurring. Also, based on land use data and known sediment delivery ratios typical for small watersheds it was suggested that agricultural and construction site land uses are the dominant upland sediment sources for this watershed. A large headcut was identified on one of the tributaries of Shoal Creek that could migrate upstream and eventually cause the upstream dam to fail (Site 43 on Map 3 of Appendix C).
4.4.2 Sediment Evaluation A sediment evaluation of Shoal Creek was conducted in 2004/2005 to determine the origin of the sediment that had accumulated in the Griffin County Club Lake. A series of soil samples were collected from along Shoal Creek and from the bottom of the Griffin Country Club Lake. Samples were analyzed to evaluate the concentration of Aluminum Sulfate and Arsenic in the soil and to determine if there was any obvious trend in these concentrations that could be traced to the City of Griffin Drinking Water Treatment Plant (DWTP) or the University of Georgia Experiment Station. Arsenic has been historically used as an herbicide by various entities. Arsenic can also be naturally occurring in soil or caused by industrial pollution. Aluminum Sulfate (Alum) is used as a flocculant to reduce the turbidity of water and also used in growing crops to change the pH of or to acidify soils. The evaluation concluded that the sediment that had accumulated in the Country Club Lake was likely the result of a combination of stream channel erosion and other upland sources. The study could not determine the amount of sediment that could have been the result of the backwashing process at the Water Treatment Plant since an estimated concentration of solids that were released during the backwashing process was unknown. The geometric mean concentration of Aluminum Sulfate collected from downstream of the Water Treatment Plant was less than the geometric mean concentration collected from upstream of the Water Treatment Plant. It is important to note that the DWTP discharged filter backwash to Shoal Creek until 1987, but has since discharged the backwash to the sanitary sewer system. The Shoal Creek Sediment Evaluation is included as Appendix D.
4.4.3 North Griffin Regional Detention Pond Water Quality Monitoring The City of Griffin completed construction of the North Griffin Detention Pond in 1998. It is located within the 180-acre North Griffin Drainage Basin, within the SC2 sub-watershed. The pond provides detention for the upstream drainage, eliminating downstream flooding while utilizing a natural wetland system to provide water quality enhancement for the sub-basin.
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The second phase of the project, completed in 1999, involved construction of a bio-engineered wetland system within the pond, planted with vegetation specifically selected to promote the breakdown of contaminants present in the stormwater runoff. The vegetated pond holds stormwater draining from the basin and releases the water slowly into an established forested wetland downstream. The system has been shown effective in reducing some pollutants by 90 percent. The Project was constructed using, in part, funds from a Clean Water Act Section 319 Grant. There are four water quality sample locations throughout the system. Sampling and analysis has been conducted since 1999 and includes the following constituents:
• Total Suspended Solids • Dissolved Oxygen • Total Dissolved Solids • pH • Turbidity • Specific Conductance • Nitrate Nitrogen • Oil & Grease • Nitrite Nitrogen • Total Petroleum Hydrocarbons • Nitrate/Nitrite Nitrogen • Fecal Coliform • Biochemical Oxygen Demand • Total Copper • Total Phosphorus • Total Lead • Total Kjeldahl Nitrogen • Total Zinc • Chemical Oxygen Demand
The Final Report for this Watershed Project was completed in 2003 (Paragon, 2003), and is available on the City of Griffin’s Stormwater Department website: http://www.griffinstorm.com/sw/Projects.htm.
4.4.4 Oakview Detention Pond Water Quality Monitoring The Oakview Drainage Improvement Project consisted of retro-fitting an existing stormwater pond that provided detention for 55 acres of commercial and multi-family residential development. The previous detention pond was undersized and did not provide the desired level of flood control. The City of Griffin undertook the task of re-designing the existing pond and downstream drainage network to the appropriate engineering standards. At the same time, the City saw an opportunity to incorporate a water quality enhancement component into the redesigned pond that ultimately resulted in a comprehensive design that addressed both water quality protection and flood control. The project was constructed in 2002. The Oakview Pond is just upstream of sample station HC1. This Project was constructed using, in part, funds from a Clean Water Act Section 319 Grant. Water quality monitoring is no longer being conducted at the Oakview Pond.
4.4.5 LSPC Hydrology and Water Quality Modeling In 2006, Tetra Tech prepared a Watershed Hydrology Report and a Water Quality Report for the City of Griffin Watersheds. The Watershed Hydrology Modeling Report presents the results for the modeling calibration and validation of the Cabin Creek (HUC8 No. 03070103, Upper Ocmulgee), Shoal Creek, Potato Creek, Heads Creek, and Honeybee Creek (HUC8 No. 03130005, Upper Flint) Watersheds. The Water Quality Report presents the results of the preliminary water quality calibration of the same watersheds. The Loading Simulation Program C++ (LSPC) was used to represent the hydrological conditions. This model is capable of representing loading, both flow and water quality, from nonpoint and point sources. The watershed model represented the variability of nonpoint source contributions through dynamic representation of hydrology and land practices. The model included all point and nonpoint source contributions. In 2008, Tetra Tech updated the hydrology model to include two
29 Shoal Creek Watershed Assessment November 2009 additional years of data. The Watershed Hydrology Modeling Report is included as Appendix E and the Water Quality Report is included as Appendix F. No scenarios have been run using these models.
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5 Data Analysis
5.1 Water Quality Analysis The water quality data analysis, with regard to the current Shoal Creek sampling effort, has been broken down into categories of similar constituents. These categories are formulated as follows: • Temperature • Oxygen Demand consisting of o Dissolved Oxygen o Biochemical Oxygen Demand o Chemical Oxygen Demand • Sediment Load expressed as Turbidity • Nutrients consisting of o Total Phosphorus o Orthophosphate o Nitrogen • Metals and Toxic Organic Compounds consisting of o pH o Specific Conductivity o Salinity o Total Zinc o Total Copper o Total Cadmium o Total Lead o Toxic Organic Compounds • Sediment Samples • Fecal Coliform Also included in this section is an analysis of the water quality of the North Griffin Regional Detention Pond. Note that the Shoal Creek water quality sample sites were not all monitored concurrently. Sites SC1 through SC9, HC1, and HC2 were monitored from July 31, 2001 through September 22, 2004, and sites SC0, SC2, SC5, SC10, HC1, and HC2 were monitored March 17, 2005 through July 6, 2009. Sites SC2, SC5, HC1, and HC2 are the only sites that have been monitored over the entire period.
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5.1.1 Temperature Human activity has affected the temperature of rivers and streams in many ways. One of the most significant mechanisms that increase water temperature is thermal pollution. Industries, such as nuclear power plants, may cause thermal impacts by discharging water used to cool machinery. Thermal impacts may also come from stormwater running off warmed urban surfaces, such as streets, sidewalks, and parking lots. The temperature of streams and rivers is also affected by the loss of riparian buffers, e.g., trees that provide shade, thereby exposing the water to more direct sunlight. Soil erosion can also contribute to warmer water temperature. As discussed later in this section, many types of activities, including the removal of streamside vegetation, overgrazing, poor farm practices, and construction, can cause soil erosion. Soil erosion raises water temperatures because it increases the amount of suspended solids carried by the river, making the water cloudy or turbid. Cloudy water absorbs the sun’s rays, causing water temperature to rise. Changes in water temperature have a profound affect on the stream ecosystem. As water temperature rises, the rate of photosynthesis and plant growth also increases. The additional plants eventually die and are decomposed by bacteria that consume oxygen. Therefore, as temperature and the rate of photosynthesis increases, so does the need for oxygen in the water (biochemical oxygen demand or BOD). The metabolic rate of organisms also rises with increasing water temperature, resulting in even greater oxygen demand. The life cycles of aquatic insects tend to speed up in warm water. Animals that feed on these insects can be negatively affected, particularly birds that depend on insects emerging at critical time periods during their migratory flights. Most aquatic organisms have adapted to survive within a range of water temperatures. Some organisms, such as trout and stonefly nymphs, prefer cooler water while others thrive under warmer conditions, e.g., carp and dragonfly nymphs. As the temperature of a stream or river increases, the warm water organisms will replace the cool water species. Few organisms can tolerate extremes of heat or cold. Temperature also affects the sensitivity of aquatic life to toxic wastes, parasites, and disease. For example, thermal pollution may cause fish to become more vulnerable to disease, either due to the stress from rising water temperatures or the resulting decrease in dissolved oxygen. Assessment: Georgia Water Use Classifications and In-stream Water Quality Standards for designated uses require that for streams with a designated use of Fishing, water temperature is not to exceed 900F and discharge to a stream cannot produce a temperature increase of more than 50F above intake temperature. All stream temperature measurements taken in the Shoal Creek Watershed, as shown in Appendix G, are well below the 90° F (32° C) maximum specified by EPD. It is clear that water temperature is not a problem in the Shoal Creek watershed.
5.1.2 Oxygen Demand
5.1.2.1 Dissolved Oxygen Dissolved oxygen (DO) is essential for the maintenance of healthy streams and rivers. The primary source of dissolved oxygen in water comes from the atmosphere through physical mixing at the air- surface water interface. Algae and rooted aquatic plants also release oxygen into streams and lakes through photosynthesis. Most aquatic plants and animals need oxygen to survive. Waters with consistently high levels of dissolved oxygen are generally considered healthy and stable ecosystems capable of supporting many different species of aquatic organisms.
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Levels of dissolved oxygen in aquatic ecosystems vary significantly depending on a number of factors. Physical influences, such as volume of discharge and water temperature directly affect oxygen concentration with levels increasing with increased mixing rates as well as decreasing temperature. During dry periods, e.g. in the summer, flow may be reduced and air and water temperatures are often higher. Both of these factors tend to reduce dissolved oxygen levels. In the spring, wet weather increases flow resulting in greater mixing and dissolution of atmospheric oxygen. Large daily fluctuations in dissolved oxygen are also characteristic of bodies of water with extensive plant growth. Levels rise in the morning through the afternoon as a result of photosynthesis, reaching a peak in late afternoon. Photosynthesis stops at night, but plants and animals continue to respire and consume oxygen. As a result, dissolved oxygen levels fall to a low point just before dawn. This phenomenon is more common in lakes and impounded rivers, than in fast flowing streams. The main factor contributing to significant changes in dissolved oxygen concentrations is the build-up of organic wastes, including leaves, feces, etc. Organic waste can enter rivers in many ways, such as in sewage, urban and agricultural runoff, or in the discharge of animal feeding operations and other industrial sources. A primary component of urban and agricultural runoff is fertilizers that stimulate the growth of algae and other aquatic plants. As plants die, aerobic bacteria consume oxygen in the process of decomposition. Many other kinds of bacteria also consume oxygen while decomposing sewage and other organic material in the river. Depletions in dissolved oxygen concentration cause major shifts in the kinds of aquatic organisms found in water bodies. Species that cannot tolerate low oxygen levels - mayfly and stonefly nymphs, caddis fly and beetle larvae, bass and trout – will be replaced by fewer kinds of pollution tolerant organisms, such as worms and fly larva, carp and catfish. Nuisance algae and anaerobic organisms may also become abundant in waters with low levels of dissolved oxygen. Assessment: Streams with a designated use of Fishing must have dissolved oxygen (DO) levels greater than 5 mg/L daily average and not less than 4 mg/L at all times to meet Georgia EPD water quality criteria for waters supporting warm water species of fish. Average DO concentrations are above 5.0 mg/L at all sites except SC1, which has an average of 4.89 mg/L. This sample station represents, for the most part, flow from the Griffin Country Club Lake. The Lake is relatively large, covering approximately 35 acres. Under normal flow conditions, the lake discharges water from its lower depths, and the water then continues downstream. Sediment deposition in the Lake may be negatively impacting dissolved oxygen. The sample station directly upstream of the Lake did not exhibit problems with dissolved oxygen, which indicates the Lake is the likely cause of lowered DO downstream. There were individual measurements from sites SC1, SC7, SC8, HC2, and SC0 that were below the absolute State minimum of 4.0 mg/L for waters supporting warm water species of fish. Sample site SC0 is just upstream of Site SC1, and essentially replaced site SC1 as the monitoring station just downstream of the Griffin Country Club Lake in 2005. Individual DO concentrations at this site have dipped below 4.0 mg/L during the past four summers. Site HC2 is the only other site that has had measurements below 4.0 mg/L since 2001. Sample station HC2 represents the smallest sub-watershed in the Shoal Creek Assessment and would probably be the most affected by warm weather and low-flow drought conditions. Dissolved oxygen levels and average DO concentrations are shown in Appendix G.
5.1.2.2 Biochemical Oxygen Demand (BOD) In streams, macroinvertebrates and bacteria transform organic matter. Biochemical oxygen demand (BOD) is a measure of the quantity of oxygen used by these microorganisms in the aerobic oxidation of organic matter. Typically the BOD measurement is conducted over a 5-day period and termed BOD5. Although this is not the ultimate oxygen demand the organic material may place on the water, the 5-day period has become the convention for reporting BOD. Measuring ultimate BOD would require several
33 Shoal Creek Watershed Assessment November 2009 weeks or more so the 5-day period has become standard. There is also some opinion that in most natural systems, after five days the oxygen demand source will have moved a considerable distance downstream, thus altering the representative nature of the original sample. The downstream flow produces mixing with other flow sources, dissolved oxygen gain and loss, and other changes that are not related to the oxygen demand characteristics of the original sample. So the BOD5 test is considered a measurement of the immediate impact within the area of the sample. There are many natural and human sources of organic material in aquatic ecosystems. Natural sources include organic matter from wetlands, bogs, and riparian vegetation, especially leaf fall. Human sources of organic material can be derived from point as well as non-point sources. Examples of point sources include pulp and paper mills, food processing industries, and wastewater treatment plants. Non-point sources of organic material are often more challenging to identify. They include: urban runoff that carries sewage from leaking sanitary sewer connections into storm drains; pet wastes from streets and sidewalks; nutrients from lawn fertilizers; leaves; grass clippings; and paper from residential areas. Runoff from agricultural fields carries nutrients, like nitrogen and phosphates, which stimulate plant growth that, in turn, leads to more plant decay over time. Nutrients have been shown to be a prime contributor to high oxygen demand in many water bodies. Runoff from animal feeding operations may also carry fecal material into rivers increasing biological oxygen demand. Finally, impounded river reaches collect organic wastes from upstream areas. Once settled in quieter waters, bacteria utilize oxygen to transform the organic matter. Percent saturation (dissolved oxygen) values in waters with much plant growth and decay often fall below 90 percent. In rivers and streams with high BOD levels, aerobic bacteria consume much of the available dissolved oxygen; little is available for other aquatic organisms. Organisms that are more tolerant of low dissolved oxygen levels may appear and become numerous. Examples include carp, midge larvae, and sewage worms. Organisms that are intolerant of low oxygen levels, such as the caddis fly larvae, mayfly nymphs, and stonefly nymphs, will not survive. As organic pollution increases, the ecological stable and complex relationships present in waters containing a high diversity of organisms is replaced by low diversity of pollution-tolerant organisms. Assessment: There is no specific State standard for BOD in surface water. However, there is a limit applied to wastewater discharges from sewage treatment plants. For example, the Potato Creek Wastewater Treatment Plant has a maximum limit ranging from a monthly average of 10 mg/L (August through September) to a monthly average of 30 mg/L (December through April). Typically, BOD levels from 3 to 5 mg/L are considered moderately clean while levels below 3 mg/L are considered very good. In 2001, the laboratory was unable to process the BOD tests at a detection limit below 5 ppm (mg/L). Under these circumstances, it is customary to calculate an average based on one- half the detection limit of the test for all below detection limit results. Using this convention, all sites have less than 5 mg/L average BOD in 2001. BOD measurements are shown in Appendix G. All individual site measurements were less than or equal to 15 mg/L. BOD site averages for the entire monitoring period (Appendix G) range from 1.58 mg/L (SC5) to 2.86 mg/L (SC3), though not all sites were monitored concurrently, as noted in Table 4-1. REF-1 had an average BOD of 1.58 mg/L over its monitoring period. Although the detection limit issue does cloud the results, the BOD results, particularly when compared to typical wastewater discharge limits, do not appear to be a problem. When examined in conjunction with the dissolved oxygen measurements, there is not an indication of excessive BOD levels in the Shoal Creek Watershed.
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5.1.2.3 Chemical Oxygen Demand (COD) COD is a measured quantity that does not depend either on the ability of microorganisms to degrade the material or on knowledge of the particular substances in question. When analyzing for COD, a strong chemical oxidizing agent is used to oxidize the organics rather than relying on microorganisms to do the job. This means the COD test will only take a matter of hours as compared to a BOD test of 5-days or more. The COD test, however, does not distinguish between the oxygen demand that will be felt in the natural environment and the chemical oxidation of inert organic matter. A COD measurement is typically higher than a BOD5, although for some easily biodegradable matter the two can be similar. For this reason, the COD test is used as a rapid way to estimate the amount of ultimate BOD. Assessment: COD measurements are shown in Appendix G. BOD and COD site averages for the entire monitoring period are also shown in Appendix G. Average COD levels are much higher than average BOD levels, which is expected. When examined in conjunction with the dissolved oxygen measurements, there does not appear to be a problem with oxygen demand in the Shoal Creek Watershed.
5.1.3 Turbidity Turbidity is a measure of the relative clarity of water; the greater the turbidity, the murkier the water. Turbidity increases as the result of suspended solids in water that reduce the transmission of light. Suspended solids vary depending upon the source of the material, ranging from clay, silt, and plankton, to industrial wastes and sewage. High turbidity may be caused by soil erosion, waste discharge, urban runoff, and abundant bottom feeders (such as carp) that stir up bottom sediments, or algal growth. The presence of suspended solids may cause color changes in water, from nearly white to red-brown, or green from algal blooms. At higher levels of turbidity, water loses its ability to support a diversity of aquatic organisms. Murkier waters become warmer as suspended particles absorb heat from sunlight, causing oxygen levels to fall. Photosynthesis decreases because less light penetrates the water causing further decreases in oxygen content. The combination of warmer water, less light, and oxygen depletion makes it impossible for some forms of aquatic life to survive. Suspended solids affect aquatic life in other ways. Suspended solids can clog fish gills, reduce growth rates, decrease resistance to disease, and prevent egg and larvae development. Particles of silt, clay and organic materials settle to the bottom, especially in slower moving rivers and streams. These settled particles could smother the eggs of fish and aquatic insects, as well as suffocate newly hatched insect larvae. Material that settles into spaces between rocks makes these microhabitats unsuitable for mayfly nymphs, stonefly nymphs, caddis fly larvae, and other aquatic insects living there. Turbidity measurements are reported as nephelometric turbidity units (NTUs). There is a maximum limit which ranges from 50 NTUs to 750 NTUs listed in Georgia EPD’s Construction Activity NPDES discharge permit. In Appendix B of this permit, there are two tables listing limit NTU requirements based on the size of the construction site and the drainage area of the receiving stream, as well as whether it is a cold water or warm water fishery. The lowest maximum limit value of 50 NTUs is found in the warm water table. Assessment: EPA Rules and Regulations (391-3-6-.03) state that all waters shall be free from turbidity which results in a substantial visual contrast in a water body due to a man-made activity. Since no quantity is specified for this standard, the NPDES permit lowest maximum limit allowed for discharge from a construction site (50 NTUs) can be used as a reference point. Turbidity measurements and average turbidity levels are presented in Appendix G. In general, each monitoring station had one or two turbidity measurements that
35 Shoal Creek Watershed Assessment November 2009 exceeded 50 NTUs. Sites SC1 and HC1 are the only sites in the Shoal Creek Watershed that never had a measurement that exceeded 50 NTUs. Site SC1 is directly downstream of the Griffin Country Club Lake and Site HC1 is directly downstream of the Oakview Detention Pond. This indicates that these ponds are effectively reducing turbidity by allowing fine particles to settle out before water is released downstream. The reference site, REF-1, had the highest recorded measurement (228 NTUs) following a large storm event. High turbidity measurements are generally associated with wet weather events, but three of the measurements that exceeded 50 NTUs, at sites SC2, SC3, and SC4, were from dry weather sampling events. In these instances, the turbidity could have been the result of construction or agricultural activities. There is no site that is consistently higher than the others, so it doesn’t appear that land use practices at any particular location are causing chronic turbidity problems. There is not a great deal of new development occurring in the Shoal Creek Watershed, although it only takes one or two disturbed sites without adequate erosion control to critically increase turbidity.
5.1.4 Nutrients
5.1.4.1 Total Phosphorus
Phosphorus is usually present in natural waters as phosphate (PO4-P). Organic phosphate is a part of living plants and animals, their by-products, and their remains. Inorganic phosphates include the ions = (H2PO-2, HPO=4, and PO 4) bonded to soil particles, and phosphates present in laundry detergents. Phosphorus is an essential element for life. It is a plant nutrient needed for growth, and a fundamental element in the metabolic reactions of plants and animals. Plant growth is limited by the amount of phosphorus available. In most waters, phosphorus functions as the growth limiting factor because it is usually present in very low concentrations. Any unattached or “free” phosphorus, in the form of inorganic phosphates, is rapidly taken up by algae and larger aquatic plants. Because algae only require small amounts of this nutrient to live, excess phosphorus causes extensive algal growth called “blooms.” Algal blooms are a classic symptom of cultural eutrophication. Cultural eutrophication, the human-caused enrichment of water with nutrients (usually phosphorus), is the primary cause of most eutrophication today. Natural eutrophication also takes place today but is insignificant by comparison. Phosphorus taken from natural sources generally becomes trapped in bottom sediments or is rapidly taken up by aquatic plants. For example, forest fires are natural events that cause eutrophication. Lakes that receive no inputs of phosphorus from human activities age very slowly. Phosphorus comes from several sources, including: human wastes, animal wastes, industrial wastes, fertilizers, and human disturbance of the land and its vegetation. Sewage from wastewater treatment plants and septic systems are major sources of phosphorus in many aquatic ecosystems. Storm sewers can also recieve flow from leaking sanitary sewer connections. Sewage from these leaks can be carried into waterways from rainfall. Phosphorus from animal wastes sometimes finds its way into rivers and lakes in the runoff from animal feeding operations. Soil erosion from agricultural and construction activities is also a primary contributor of phosphorus to many water bodies. Fertilizers used for crops, lawns and home gardens usually contain phosphorus, and when used in excess, the nutrient usually ends up in streams, rivers, and lakes. Draining swamps and marshes for farmlands, housing, commercial, and/or industrial parks releases nutrients like phosphorus that have remained dormant in years of accumulated organic deposits. In addition, drained wetlands no longer function as filters of silt and phosphorus, allowing more runoff – and phosphorus - to enter waterways. Shallow lakes and impounded river reaches, where the water is shallow and slow moving, are the most vulnerable to the effects of cultural eutrophication. As mentioned previously, phosphorus stimulates the growth of algae and rooted vegetation, the latter that takes up phosphorus previously locked in bottom
36 Shoal Creek Watershed Assessment November 2009 sediments and releases it to water, causing further eutrophication. As eutrophication increases, swimming and boating may become impossible. Eventually, the entire lake or river stretch may fill with aquatic vegetation. The advanced stages of cultural eutrophication can produce anaerobic conditions in which oxygen in the water is completely depleted. These conditions occur near the bottom of a lake or impounded river stretch, and produce gases like hydrogen sulfide, unmistakable for its “rotten egg” smell. Total phosphorus should not exceed 0.1 mg/L in streams that do not discharge directly into lakes or reservoirs (Muller and Helsel, 1996). Sites generally had one or two individual measurements that exceeded 0.1 mg/L. Site SC8 is the only site that never exceeded 0.1 mg/L. Individual measurements in Shoal Creek were all below 0.5 mg/L. The Shoal Creek sites all have average Phosphorus concentrations less than or equal to 0.1 mg/L. Reference site REF-1, however, has an average total phosphorus concentration of 0.14 mg/L. Refer to Appendix G for total phosphorus levels and average total phosphorus levels.
5.1.4.2 Orthophosphate Orthophosphate is the form of phosphorus that is directly usable by plants, so it immediately begins to act as a fertilizer once it is released. As with total phosphorus, an orthophosphate level above 0.1 mg/L is a cause for concern. All the Shoal Creek sample locations averaged 0.03 mg/L or less, and had no individual measurements greater than 0.08 mg/L. Reference site REF-1 had one measurement of 1.0 mg/L and one measurement of 0.37 mg/L. Refer to Appendix G for orthophosphate levels and average orthophosphate levels.
5.1.4.3 Nitrogen Nitrogen is an element needed by all living plants and animals to make protein. In aquatic ecosystems, nitrogen is present in many forms. Nitrogen is a much more abundant nutrient than phosphorus in nature. It is more commonly found in its molecular form (N2), which makes up 79 percent of the air we breathe. This form is useless for most aquatic plant growth. Blue-green algae, the primary algae of algal blooms, are able to use N2 and convert it into other forms of nitrogen, specifically: ammonia (NH3) and nitrate - (NO 3), that plants can take up through their roots and use for growth. Animals obtain the nitrogen they need by either eating aquatic plants or eating other aquatic organisms that feed upon the plants. As aquatic plants and animals die, bacteria break down large protein molecules into ammonia. Ammonia is - - then oxidized by other bacteria to form nitrites (NO 2) and nitrates (NO 3). Excretions of aquatic organisms are very rich in ammonia, although the amount of nitrogen they add to waters is usually small. Duck and geese, however, contribute a heavy load of nitrogen (from excrement) in areas where they are plentiful. Through decomposition of dead plants and animals, and the excretions of living animals, nitrogen that was previously “locked-up” is released. There are also bacteria that can - transform nitrates (NO 3) into free molecular nitrogen (N2). The nitrogen cycle begins again if this free molecular nitrogen is converted by blue-green algae into ammonia and nitrates. Because nitrogen, in the form of ammonia and nitrates, acts as a plant nutrient, it also causes eutrophication. As described in the previous section on phosphorus, eutrophication promotes plant growth and decay, which in turn increases biological oxygen demand. However, nitrogen, unlike phosphorus, rarely limits plant growth, so plants are not as sensitive to increases in ammonia and nitrate levels. Sewage is the main source of nitrates added by humans to rivers. Sewage enters waterways in inadequately treated wastewater from sewage treatment plants, in the effluent from leaking sanitary sewer connections, and from poorly functioning septic systems. Septic systems, more common in rural areas, generally treat waste from a single household. If these systems are located too close to the water table or if the systems are not emptied periodically, nutrients and bacteria can get into the drinking water supply
37 Shoal Creek Watershed Assessment November 2009 from a nearby well or can travel through the ground or through surface runoff to nearby streams and lakes. Water containing high nitrate levels can cause a serious condition called methemoglobinemia, if used to make infant milk formula. This condition prevents the baby’s blood from carrying oxygen; hence the nickname “blue baby” syndrome. Two other important sources of nitrates in water are fertilizers and runoff from cattle feedlots, dairies and barnyards. High nitrate levels have been found in groundwater beneath croplands due to excessive fertilizer use, especially in heavily irrigated areas with sandy soils. Stormwater runoff can carry nitrate- containing fertilizers from farms and lawns into waterways. Similarly, places where animals are concentrated, such as feedlots and dairies, produce large amounts of waste rich in ammonia and nitrates. If not properly contained and treated, bacteria and nutrients can seep into groundwater or be transported to surface waters. As discussed previously, eutrophication can limit organism diversity, recreational opportunities, and property values. Typically, concentrations of total nitrate nitrogen above 10 mg/L, nitrite above 0.1 mg/L, ammonia nitrogen above 2 mg/L, and total Kjeldahl nitrogen above 2 mg/L are a concern, and suggest that actions should be taken to identify sources and limit inputs of nitrogen in the ecosystem of concern. Nitrate/Nitrites Nitrate is the most common form of nitrogen found in water. It is not particularly toxic itself, but infants can potentially convert nitrates to highly toxic nitrites creating a toxic blood oxygen condition. Therefore, a drinking water standard exists for both nitrates and nitrites. The EPA has established a maximum contaminant level (MCL) of 10 mg/L (as nitrogen) for nitrate in drinking water (Muller and Helsel, 1996). Nitrate levels and average nitrate levels are shown in Appendix G. The highest individual nitrate measurement was 2.4 mg/L and average nitrate levels range from 0.62 mg/L to 1.32 mg/L, all much less than the 10 mg/L standard for concern. None of the Shoal Creek sites had nitrite measurements over the 0.1 mg/L standard for concern, but reference site REF-1 had one measurement greater than 1 mg/L. Ammonia Nitrogen Ammonia nitrogen is the main product produced from the decomposition of plant and animal material. Ammonia nitrogen in the NH3 form is extremely toxic to fish populations even at low levels and can cause various problems including, a reduction in hatching success, reduction in growth rate and morphological development, and pathologic changes in tissues of gills, livers, and kidneys. In most natural surface waters, total ammonia concentrations greater than about 2 mg/L exceed the chronic exposure criteria for fish (Muller and Helsel, 1996). None of the Shoal Creek sites had ammonia measurements over the 2.0 mg/L standard for concern. Ammonia levels and average ammonia levels are shown in Appendix G. Total Kjeldahl Nitrogen This is a measure of both the ammonia and organic forms of nitrogen. A concentration of 2.0 mg/L is considered a critical level to water quality and organism health. Individual total Kjeldahl nitrogen (TKN) measurements exceeded 2.0 mg/L at four of the twelve sample stations (SC2, SC5, HC2, and SC0), with the highest recorded measurement of 10 mg/L occurring at site HC2. All of the TKN averages are below 2.0 mg/L. TKN levels and average TKN levels are shown in Appendix G.
5.1.4.4 Nutrient Assessment Two of the six constituents used to assess nutrient levels (phosphorous and TKN) were found to have individual measurements of some concern in the Shoal Creek Watershed. Since total Kjeldahl nitrogen
38 Shoal Creek Watershed Assessment November 2009 was found at elevated levels at sites where ammonia was never at a level of concern (SC2, SC5, HC2, and SC0), some organic nitrogen loading may be occurring in these areas. Site averages for each of the nutrients examined are below the standards for concern. Incidences of nutrient measurements occurring at elevated levels are rare, and do not indicate persistent conditions. Nor do the measurements point to any subwatershed as being particularly problematic. Nutrient loading does not appear to be a serious problem in Shoal Creek, but some impairment may be occurring from the occasional spikes in phosphorous and TKN levels.
5.1.5 Metals and Toxic Organic Compounds Volcanic eruptions, weathering of rock, and other natural processes continually introduce and cycle metals in the environment. This geological weathering is responsible for the background levels of metals found in rivers and lakes. Natural processes and cycles are often disrupted by human activity such as mining (e.g., lead, silver, copper, and iron ore) and manufacturing processes that redistribute and concentrate metals in the environment. Metals are often found in the effluent of various manufacturing processes, including: lead and nickel in battery manufacturing, copper from the textile industry, silver in photographic film production, and iron ore in steel production. Other point sources, like sewage effluent, may contain elevated levels of copper, lead, zinc, and cadmium. Some of this increase has been linked to corrosion within the wastewater collection system. Non-point sources of pollution include both urban and rural runoff. Urban stormwater runoff carries increased metal loadings, especially during the initial “first flush” phase of the rain event. Stormwater carries lead deposited on streets and parking lots from car exhaust, oil and grease, zinc in motor oil and grease, and copper worn from metal plating and brake linings. In rural areas, sediments eroding from croplands carry cadmium, and even uranium, which are both found in some phosphate fertilizers. Herbicides used to control weeds may also contain arsenic. In addition, metals used in products common to our daily life, like cars, eventually end up in landfills, or their by-products can be transported via stormwater to a nearby water body. Many metals are essential for plant and animal growth and metabolism. Nickel, zinc, and copper are considered essential elements. Essential trace metals, at excessive levels, become toxic to invertebrates and fish. Often the difference between non-toxic and toxic levels is minute. Non-essential elements, such as cadmium, mercury, and lead, are toxic even at very low levels. Toxicity refers to the potential harmful effects, both lethal as well as non-lethal, of a chemical upon a living organism. Potential effects may include the inability to reproduce, behavioral changes, and/or changes in growth and development. It is often difficult to differentiate the many interconnected effects related to toxic metals. For example, a fish that is stressed by accumulation of metals may become physically less able to avoid predation. The toxicity of heavy metals to aquatic organisms depends upon many factors, including the bio- availability of metals to organisms. Organisms take up metals through ingestion of food, through adsorption onto membranes (gills), and transport through the skin. Bio-availability, in turn, is influenced by water hardness, pH, life cycle, and age of the organism, and water temperature. With increasing water hardness, the toxicity of metals decreases, as they are adsorbed onto insoluble carbonate compounds. A lowering of the pH increases the solubility of metals in solution. Below a pH of 5.5, aluminum and mercury levels may be a threat to aquatic life. Concentrations of metals, like mercury, are often higher in older organisms. An increase in water temperature increases metabolism and quickens the intake of metals as well. Metals are adsorbed onto organic material and so are found concentrated in bottom sediments. Organisms that inhabit metal-laden sediment, e.g., Tubifex, exhibit high levels of metals. People who eat bottom-feeding fish like carp and catfish on a frequent basis may be at increased health risk.
39 Shoal Creek Watershed Assessment November 2009
5.1.5.1 pH
Water (H2O) contains both H+ (hydrogen) ions and OH- (hydroxyl) ions. The pH test measures the H+ ion concentration of liquids and substances, with resulting values reported on a scale from 0 to 14. Pure deionized water contains equal numbers of H+ and OH- and has a neutral pH of 7. If a water sample has more H+ than OH- ions, it is considered acidic and has a pH of less than 7. If a sample contains more OH- than H+ ions, it is considered basic with a pH greater than 7. It is important to note that for every one-unit change on the pH scale, there is approximately a ten-fold change in how acidic or basic the sample is. In the U.S., the pH of natural water is usually between 6.5 and 8.5, although wide variations can occur. In many parts of the country, increased amounts of nitrogen oxides (NOx) and sulfur dioxide (SO2), primarily from automobile and coal-fired power plant emissions, are converted to nitric acid and sulfuric acid in the atmosphere. These acids combine with moisture in the atmosphere and fall to earth as acid rain or snow that has impacted thousands of lakes (e.g. northeastern U.S.). Geology can also affect the acidity of local water. Acid mine drainage from mining operations have impacted streams and rivers in the southeastern U.S. as well as many other parts of the country. If limestone is present, its alkaline characteristics can act to neutralize the effect the acids have on lakes and streams. Water bodies most heavily impacted by acid rain are downwind of urban/industrial areas and do not have any limestone to buffer the impact of the acidity of the water. Changes in the pH value of water are important to many organisms as they have adapted to life in water of a specific pH and may die if it changes even slightly. This has occurred to brook trout in some streams in the Northeast. Impacts to biological communities are observed in streams that receive acid rain and acid snow melts in the spring. Immature stages of aquatic insects and young fish are extremely sensitive to pH values at or below 5.0. Very acidic waters can also cause heavy metals, such as copper and aluminum, to be released into the water. Heavy metals accumulate on the gills of fish or cause deformities in young fish, reducing their chance of survival. At extremely high or low pH values (e.g., 9.6 or 4.5) the water becomes unsuitable for most organisms. Georgia Water Use Classifications and In- stream Water Quality Standards for designated uses require that pH levels be between 6.0 and 8.5. Average pH levels in the Shoal Creek Watershed all fall within the minimum and maximum pH levels set forth by the State. Several individual measurements did fall outside of the state standards. Sites SC4, SC7, HC1, and HC2 each had measurements less than 6.0, though none were extreme. Reference site REF-1 had a single pH measurement of 3.56 that was extremely low. There do not appear to be any chronic pH problems in the Shoal Creek Watershed. Measured pH levels and average pH values are shown in Appendix G.
5.1.5.2 Specific Conductivity Specific conductance (conductivity) is a numerical expression of water’s ability to conduct an electrical current. It is typically measured in microsiemens per centimeter (uS/cm). Values of high specific conductance reflect the presence of high concentrations of total dissolved solids or potentially dissolved metals. Conductivity of rivers in the United States generally ranges from 50 to 1500 uS/cm. Studies of inland fresh waters indicate that streams supporting good mixed fisheries have a range between 150 and 500 uS/cm (US EPA, 1997). Conductivity outside this range could indicate that the water is not suitable for certain species of fish or macroinvertebrates. All conductivity measurements in the Shoal Creek watershed were less than 250 uS/cm. However, the reference site, REF-1, had four measurements greater than 500 uS/cm in 2005 and 2006 Conductivity is not a concern in the Shoal Creek watershed. Conductivity levels and average conductivity values are shown in Appendix G.
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5.1.5.3 Salinity Salinity is the mass of dissolved salts, present in the form of charged ions, in a given volume of water; and may include sodium, calcium and magnesium (positive ions) and chloride, carbonate and bicarbonate and sulfate (negative ions). Dissolved salts impart distinctive physical characteristics to the water body, such as salty taste (sodium salts) or hardness (calcium salts). The level of dissolved salts in fresh water streams is important ecologically. Salinity changes can affect aquatic ecosystems directly by changing the relative proportions of solutes and the solubility of dissolved gases such as oxygen and nitrogen, or indirectly by modifying the species composition of the ecosystem. Aquatic organisms vary greatly in their ability to tolerate changes, but many species are able to adapt to only a very narrow range of salinities, so it is important that levels do not fluctuate greatly from natural conditions. Salinity is typically measured on what is termed the practical salinity scale (PSS). The scale is exactly what its name implies - A practical scale based on the precise measurement of the electrical conductivity of a range of solutions of known salinity. It was created by a multi-national team to obtain a uniform method for reporting salinities so that results obtained from different sources can be directly compared. The relationships derived from the scale relate salinity, conductivity, temperature & pressure and uses a standard salinity solution as a datum point. This is taken to have a conductivity of 42.914 mS/cm at 15ºC and atmospheric pressure. Practical salinity is a ratio and therefore does not have units, but it can be correlated to specific conductivity. Normal seawater has a specific conductivity in the range of 50,000 - 60,000 uS/cm. As a percentage, normal seawater has a salinity of 3.3%. Shoal Creek sites all had salinity measurements less than or equal to 0.06 (PSS). Salinity is not a concern in the Shoal Creek watershed. Salinity levels and average salinity values are shown in Appendix G.
5.1.5.4 Total Zinc The Georgia EPD has set for freshwater ecosystems an acute and chronic maximum standard of 65 µg/L (0.065 mg/L) for the dissolved fraction of zinc. Acute levels are those in which aquatic life will suffer deleterious effects after a short period of exposure, typically one hour. Chronic levels are those in which aquatic life will suffer deleterious effects after a prolonged exposure, typically four days. The dissolved fraction of zinc is a function of total hardness. Currently, the City of Griffin has data on total zinc concentrations, but does not have hardness data which would be necessary to convert the total concentrations to the dissolved concentrations. Total zinc levels and average total zinc values are shown in Appendix G. This data shows the relative distribution of zinc throughout the watershed, but can not be directly related to the state toxicity standards. The City will begin sampling hardness, as calcium carbonate (CaCO3), in fiscal year 2010-2011. This sampling will allow the City to calculate dissolved metal concentrations based on measured total metal concentrations.
5.1.5.5 Total Copper The Georgia EPD has set for freshwater ecosystems an acute maximum standard of 7.0 µg/L (0.007 mg/L) and a chronic maximum standard of 5.0 µg/L (0.005 mg/L) for the dissolved fraction of copper. The dissolved fraction of copper is a function of total hardness. Currently, the City of Griffin has data on total copper concentrations, but does not have hardness data which would be necessary to convert the total concentrations to the dissolved concentrations. Total copper levels and average total copper values are shown in Appendix G. This data shows the relative distribution of copper throughout the watershed, but can not be directly related to the state toxicity standards. The City will begin sampling hardness, as calcium carbonate (CaCO3), in fiscal year 2010-2011. This sampling will allow the City to calculate dissolved metal concentrations based on measured total metal concentrations.
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5.1.5.6 Total Cadmium and Total Lead The City of Griffin measures Total Cadmium and Total Lead at all sample sites. Neither of these metals were ever measured above detection limits during the monitoring period.
5.1.5.7 Toxic Organic Compounds Like metals, organic chemical contaminants, such as pesticides, polycyclic aromatic hydrocarbons, and other chlorinated compounds can interfere with normal biological processes or even be lethal to aquatic organisms in certain conditions. These chemicals are produced and released into the environment as point source pollution through inadequate treatment of by-products of industrial processes, households products (e.g., bleach and drain cleaners), or as non-point source pollution through street runoff, atmospheric deposition, herbicide and insecticide runoff from croplands and residential areas, etc. Some toxins bind to soil particles and are easily washed into water bodies where they cause an overall decline in numbers and types of aquatic organisms found there. Some types of midges and aquatic worms are more tolerant than other organisms, so their numbers may increase although overall stream diversity will go down. Toxic organic compounds can enter the food chain through organisms that process sediment. As other animals eat these organisms, they are in turn eaten by larger animals higher in the food chain. Thus, toxins can accumulate in a process called bioaccumulation. In larger fish, toxins can cause lesions and deformities. Many of these contaminants are difficult to monitor directly and so require more expensive and time- consuming laboratory tests of water samples. Often, a Priority Pollutant scan will be carried out to determine if toxic organic chemicals are present. This analysis results in the measurement of numerous compounds, including nearly 35 volatile organics, 60 chlorinated aromatics, 26 pesticides, 10 herbicides, as well as 15 metals. If the results indicate that one or more of the chemicals are present at levels of concern (above U.S. Environmental Protection Agency Water Quality Criteria), additional samples will likely be taken in hopes of effectively characterizing the extent and source of the pollutant into the system. In addition, macro-invertebrates and fish samples may be collected and analyzed to determine if levels in their tissue are a concern to human health. Laboratory toxicity testing of sediments and water using a variety of sensitive aquatic species may also be carried out to evaluate overall impacts to the aquatic ecosystem and human health. A Priority Pollutant scan was conducted for a wet event at samples from two strategic sample locations. The sample sites selected for Priority Pollutant scans were SC1 and SC5. The selection of these sites for a Priority Pollutant sample during an increased runoff event ensured that the major portions of the Shoal Creek Watershed would be represented by a sample. The presence of any of the 129 separate compounds at problematic levels would indicate a problem somewhere in the study area and would warrant additional investigation. No toxic organic compounds were detected in the Priority Pollutant scans. Zinc was found at site SC1 (26 µg/L) and at site SC5 (21 µg/L), but both measurements were below the acute (and chronic) state standard of 65 µg/L. Laboratory reports for the Priority Pollutant scans are found in Appendix H.
5.1.5.8 Metals and Toxic Organic Compound Assessment Some of the Shoal Creek sample sites have occasionally had pH measurements that are below the state minimum of 6.0. However, the instances are rare, and there have not been measurements below 6.0 since 2005. The pH levels in the Shoal Creek Watershed do not appear to be a serious concern. The presence of zinc and copper throughout the watershed is a potential concern, though their presence is not surprising. These metals are commonly detected in urban watersheds. Copper and zinc are toxic when they are present at high enough concentrations; once hardness data is collected in this watershed, the
42 Shoal Creek Watershed Assessment November 2009 dissolved fractions of these metals can be calculated to determine whether or not state water quality standards are being violated. The source of Copper throughout the Watershed is likely from automobile brake pads, though it can also originate from agricultural operations or industrial facilities. It should be noted that studies have shown that the copper from stormwater runoff, particularly brake pad-derived copper is in nontoxic/non-available forms (Lee and Jones-Lee, 2000).
5.1.6 Sediment Samples Sediments containing elevated levels of nutrients, metals and organic pollutants have been found in freshwater, estuarine, and marine ecosystems though out the world. While some of these contaminants are present in elevated concentrations as the result of natural processes, in most cases inputs are derived from anthropogenic sources, such as effluent discharge, non-point sources, spills, atmospheric deposition, etc. A study on sediment contamination in surface waters in the United States found that thousands of waterbodies in hundreds of watersheds throughout the country contain sampling stations classified as Tier 1, a designation for sites where associated adverse effects on aquatic life or human health are probable. Several watersheds found in Georgia and neighboring states have been identified as containing areas of probable concern for sediment contamination, including: Lower Savannah, Cumberland-St. Simons, Middle Chattahoochee-Lake Harding, and the Middle Tennessee-Chickamauga (US EPA 2004). In addition, there were 4,249 fish advisories in the U.S. in 2008, many of which may be traced to sediment contaminants (US EPA, 2009). Contaminated sediments can cause either immediate or long-term deleterious (e.g., impaired growth or reproduction, lesions) effects on organisms. Bioaccumulation of chemicals is also a concern from both ecological and public health perspectives. The three potential routes of exposure to benthic organisms are the sediments themselves (e.g., ingestion), interstitial (pore) water (e.g., across respiratory surfaces and across body walls), and/or overlying water. It is important to note that toxicity and bio-availability of sediment-sorbed contaminants are linked to a number of factors, including: sediment collection, storage and handling; routes of exposure; presence of other chemicals; type of organism and feeding habits; and modifying factors (e.g., sediment characteristics). A thorough understanding of these factors is essential for designing and interpreting site-specific sediment quality assessment studies. It is equally important in the identification and implementation of effective remedial alternatives for reducing/eliminating the risks posed by contaminated sediments.
Determining Site-Specific Impacts from Contaminated Sediments Although the knowledge base about the nature and extent of contaminated sediments has grown in the past ten years, many questions remain with respect to determining site-specific impacts to both the environment and public health. For example, there is presently no clear understanding of the overall impacts of contaminated sediments at the community or ecosystem level. We can measure toxicological impacts as well as tissue uptake of chemicals to sensitive species in the laboratory, however extrapolation of this information into the field is often difficult and controversial. We can also measure chemical concentrations in sediment, but current approaches for predicting bio-availability in organisms are few and often inaccurate. Nevertheless, many advances in sediment quality assessment have been made in recent years. Currently available methodologies can be grouped in five main categories: sediment chemistry, tissue chemistry, sediment toxicity, community structure, and pathology. In an ideal world, all five components would be utilized to assess sediment quality providing maximum information about the ecosystem. In the real world, however, resources are limited so environmental managers must balance level of effort with type/quality of information needed for effective decision-making. The current recommendation is to take a phased approach to sediment quality assessment, beginning with a limited sampling effort to collect baseline data to determine the general types and concentrations of pollutants that may be present. If contaminants are found to occur above recommended thresholds (to be discussed below), a
43 Shoal Creek Watershed Assessment November 2009 comprehensive sampling and testing protocol (including laboratory toxicity and bioaccumulation studies, and field tissue studies) should then be carried out to determine the nature and extent of the sediment contamination. This information can be used later in the process to identify remedial approaches that may be used to reduce risk to the environment and public health. It should be noted that the design of the sediment quality study is site-specific and should be developed using input from all stakeholders. This is especially important when contamination is extensive, and the costs of both assessment and cleanup are high. In the initial screening level study, identification of potential chemicals of concern can be done by evaluating potential sources of current as well as historical point and non-point source pollution into the ecosystem. Sediment samples should consist of the fine-grained material from depositional areas. As mentioned previously, careful sample design, collection and processing is vital to sediment integrity, which, if disrupted, influences their chemical composition and toxicity, thereby making accurate assessment of sediment quality extremely challenging. Sediment chemistry data can be evaluated through the use of numerical sediment quality guidelines (SQG) to estimate the potential for adverse effects to biota. Within the last twenty years, SQGs for freshwater, estuarine, and marine ecosystems have been developed using a variety of approaches. Each of these approaches has certain advantages and disadvantages that influence their application in the sediment quality assessment process. A group of researchers compiled the various published SQGs to develop a list of consensus-based SQGs for 28 chemicals of concern (i.e., metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and pesticides) in freshwater sediments (MacDonald et al., 2000). For each contaminant of concern, two values were developed: a threshold effect concentration (TEC) – the concentration of contaminants below which the incidence of toxicity to sediment-dwelling organisms was not expected to occur; and a probable effect concentration (PEC) – the concentration of contaminants above which the incidence of toxicity to sediment-dwelling organisms was expected to occur. Careful evaluation of these thresholds using data from field studies conducted throughout the nation suggests that these SQGs are a useful tool for evaluating sediment quality data in Georgia’s freshwater ecosystems. The recommended TECs and PECs are found in the following table.
Table 5-1. Consensus-Based Effect Concentrations for Pollutants in Freshwater Sediments Metals (in mg/kg DW)
Parameter Methodology Detection Limit TEC PEC Arsenic EPA 7060 3 9.79 33.0 Cadmium EPA 6010 0.99 0.99 4.98 Chromium EPA 6010 1 43.4 111 Copper EPA 6010 2 31.6 149 Lead EPA 6010 2.5 35.8 128 Mercury EPA 7471 0.18 0.18 1.06 Nickel EPA 6010 2 22.7 48.6 Zinc EPA 6010 2 121 459
Polycyclic Aromatic Hydrocarbons (in µg/kg DW)
Parameter Methodology Detection Limit TEC PEC Anthracene EPA 8310 33 57.2 845 Fluorene EPA 8310 33 77.4 536 Naphthalene EPA 8310 33 176 561
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Phenanthrene EPA 8310 33 204 1170 Benz[a]anthracene EPA 8310 33 108 1050 Benzo(a)pyrene EPA 8310 33 150 1450 Chrysene EPA 8310 33 166 1290 Dibenz[a,h]anthracene EPA 8310 33 33.0 NA Fluoranthene EPA 8310 33 423 2230 Pyrene EPA 8310 33 195 1520 Total PAHs EPA 8310 33 1610 22800
Polychlorinated Biphenyls (in µg/kg DW)
Parameter Methodology Detection Limit TEC PEC Total PCBs EPA 8082 33 59.8 676
Organochlorine Pesticides (in µg/kg DW)
Parameter Methodology Detection Limit TEC PEC Chlordane EPA 8081 17 3.24 17.6 Dieldrin EPA 8081 3.3 1.90 61.8 Sum DDD EPA 8081 6.6 4.88 28.0 Sum DDE EPA 8081 6.6 3.16 31.3 Sum DDT EPA 8081 6.6 4.16 62.9 Total DDTs EPA 8081 6.6 5.28 572 Endrin EPA 8081 6.6 2.22 207 Heptachlor epoxide EPA 8081 3.3 2.47 16.0 Lindane (gamma-BHC) EPA 8081 3.3 2.37 4.99
Assessment Sediment samples were collected at all monitoring sites in the Shoal Creek Service Area on two occasions, November 27, 2001 and September 2, 2003. Six metals were detected: c hromium, nickel, arsenic, copper, zinc, and lead. Chromium, nickel, arsenic, copper, and zinc were each detected below the TEC level listed in Table 5-1. Lead was detected at 52 mg/Kg at site SC8 in 2003. This mea surement is above the TEC concentration, but below the PEC concentration liste d in Table 5-1. No Polyc yclic Aromatic Hydrocarbons, Poly chlorinated Biphenyls, o r Organochlo rine Pesticides were detected in any of the sediment samples. However, some of the detection limits are above the TEC levels while they are all below the PEC levels. Sediment contamination does not appear to b e a serious prob lem in th e Shoal Creek Watershed, but sedimen t monitoring should co ntinue to be con ducted every f ew years to identify any changes that occur, particularly for lead, which was detected ab ove Threshold E ffect Con centrations.
5.1.7 Fecal Coliform Fecal coliform bacteria are found in the feces of humans and other warm-blooded animals. These bacteria can enter rivers through direct discharge from mammals and birds, from ag ricultural and storm runoff carrying animal waste, an d from human sewag e discharged into the water. Fecal coliform bacteria by themselves are not pathogen ic. Pathogenic organisms that cause diseases and ill nesses inc lude not only bacteria, but viruses and parasites as well. Fecal coliform bacteria occur naturally in the human
45 Shoal Creek Watershed Assessment November 2009 digestive tract and aid in the digestion of food. In infe cted individua ls, pathogenic organisms are found along with fecal coliform bacteria. Pathogens are relatively scarce in water, making them difficult and time-consuming to monito r. Instead, fecal coliform levels are monito red because of the correlation betwe en fecal colifor m counts and the presence of pathogenic organisms. If an analysis indicates the prese nce of fecal col iform cou nts are higher than 200 colonies per 100 milliliters (CFU/100 mL) of stream water sampled, the potential for pathogenic organisms to be present also exists. A person swimming in such waters has a grea ter chance of getting sick from swallowing disease-causing organisms, or from pathogens ente ring the bo dy through cuts in the skin, the nose, mouth, or the ears. Diseases and illness su ch as typhoid fe ver, gastro enteritis, dysentery, and ear infections can be contracted in waters with high fecal coliform counts. Cities and small towns sometimes contribute human wastes to local rivers through their sewer systems. A sewer system is a network of underground pipes that carry wastewater. In a separat e sewer s ystem, sanitary wastes flow through sanitary sewers and are treated at the w astewater treatment plant. Storm sewers carry stormwater runoff from streets, and discharge untreated stormwater directly into streams and rivers. Rainfall can wash animal wastes produced by pets, birds, squirrels, etc. from lawns, sidewalks, and streets into streams. Rainfall can also flush fecal coliform from sanitary sewer overflows into streams. In a combined sewer system, both sanitary wastes and storm runoff are tre ated at the wastewater treatment plant. Griffin has separate sewer sys tems to handle stormwa ter and sanitary flows. Stormw ater is directed into the streams while sanitary flow s are directed to the various Water Po llution Control Plants. T he Shoal Creek Wastewater Treatment P lant does not discharge to Shoal Creek, but routes its discharge to the Blanton Mill Land Application System facility. Georgia has several sets of Stan dards depending on the water use classific ation of the water body in question. The following stand ard applies to streams used for fishing : “For the mont hs of Ma y through October, when water contact recrea tion activities are expected to occur, fecal coliform not to exceed a geometric mean of 200 per 100 mL based on at least four samples collected from a given sampling site over a 30-day period at intervals not less than 24 hour s. Should water quality and sa nitary stu dies show fecal coliform levels from non-human sources exceed 200/100 mL (geometric mean) occasionally, then the allowable geometric mean fecal coliform shall not exceed 300 per 100 mL in lakes and reservoirs and 500 per 100 mL in free flowing freshwater streams. For the months of November through April, fecal coliform not to exceed a geometric mean of 1,000 per 100 mL based on at least four samples collected from a given sampling site over a 30-day period at intervals not less than 24 hours and not to exceed a maximum of 4,000 per 100 mL for any sample….” Assessment Fecal Coliform has not yet been sampled in such a way that the geometric mean can be calculated according to EPD methodology. Beginning in fiscal year 2010-2011, the City will begin sampling fecal coliform between May and October in order to determine the geometric mean of bacteria in the watershed. However, fecal coliform data has been collected for several years, and can provide information that would help to identify problem areas. Fecal Coliform levels are presented in Appendix G. Average fecal coliform levels are also presented in Appendix G, depicting averages of samples collected May through October and those collected November through April. The winter averages for site SC10 exceeded the State criteria for geometric mean fecal coliform levels, with a winter average of 1113/mL, due to two high measurements that were taken during wet weather events. The average for reference site REF-1 exceeded the State standard, solely due to one large storm event in 2008. The State standard of 4,000 colonies/100 mL (instantaneous max) for winter months was also exceeded at site SC10 and the reference site, on one occasion each; both were associated with a large storm event in 2008 that had greater than two inches of rainfall in a two-day period. Although it does not constitute a violation, there were other fecal coliform measurements that exceeded 4000 colonies/100 mL in summer months, all
46 Shoal Creek Watershed Assessment November 2009 were recorded during wet weather sampling events. Since there are no studies at this time that indicate the fecal coliform is from non-human sources, the stricter standards of 200 colonies/100 mL for free flowing streams is used as a reference point for summer months. Site averages are above State standards at all sample sites except for SC1 for summer months. It may be advantageous for the City of Griffin to identify the source of fecal coliform in the Shoal Creek watershed, similar to the Bacterial Identification Study that was done for Potato Creek. As there are no sites that have consistently higher levels than other sites, it can be assumed that the source is widespread throughout the watershed. A large portion of the land draining to Shoal Creek Service Area monitoring stations is residential. This makes pet waste a possible candidate for the primary source of fecal coliform bacteria, since all pet waste that is not picked up, is washed into the stormwater system, and discharged to streams without any treatment. Waste from wild animals such as geese, ducks, deer, etc., may also be contributing to the problem.
5.1.8 North Griffin Regional Detention Pond As described in section 4.4.3, water quality sampling has been conducted at this stormwater detention facility since 1999. However, since 2002, only two sampling events have occurred, one on November 11, 2007, and one on December 11, 2008. Both of these were wet-weather sampling events. Table 5-2 presents the average concentrations of various parameters at the pond influent (location 1) and the pond effluent (location 2), and the pollutant removal efficiency for each parameter. The 2007-2008 data do not indicate that pollutant reductions are occurring within the pond for most parameters. The reasons for this are not clear. Future monitoring will be useful in understanding the situation more fully. Unfortunately, it is difficult to get an accurate estimate of the pollutant removal efficiency of the pond given the current sampling methods. The 2007 and 2008 sampling events results are from grab samples that were taken approximately at the same time and are not flow weighted or complete hydrograph samples.
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Table 5-2. North Griffin Regional Detention Pond Pollutant Removal Efficiency 1999-2002 Sampling Location 1 Location 2 Pond Influent Pond Effluent (Average (Average Average Annual 1999-2002 1999-2002 Pollutant Removal Parameter Results) Results) Efficiency Total Suspended Solids (mg/L) 74.57 49.64 33% Nitrate Nitrogen (mg/L) 0.47 0.18 62% Nitrite Nitrogen (mg/L) 0.03 0.06 -100% Total Phosphorus (mg/L) 0.24 0.11 54% Total Kjeldahl Nitrogen (mg/L) 3.41 1.37 60% Chemical Oxygen Demand (mg/L) 61.56 42.81 30% Fecal Coliform (#/100mL) 21963.31 812.13 96% Total Zinc (mg/L) 0.20 0.11 45%
2007-2008 Sampling* Location 1 Location 2 Pond Influent Pond Effluent Average Average Average Annual 2007-2008 2007-2008 Pollutant Removal Parameter Results Results Efficiency Total Suspended Solids (mg/L) 5.50 6.00 -9% Nitrate Nitrogen (mg/L) 0.90 0.50 44% Nitrite Nitrogen (mg/L) 0.01 0.01 0% Total Phosphorus (mg/L) 0.08 0.18 -133% Total Kjeldahl Nitrogen (mg/L) 1.00 1.15 -15% Chemical Oxygen Demand (mg/L) 19.00 26.00 -37% Fecal Coliform (#/100mL) 1760.00 2852.50 -62% Total Zinc (mg/L) 0.12 0.10 17% *Sampling was conducted on November 15, 2007 and December 11, 2008 0.24 inches of rain was recorded on November 15, 2007 1.05 inches of rain was recorded on December 10, 2008 and 1.08 inches of rain was recorded on December 11, 2008
5.2 Land Use Analysis It is evident from the 2006 aerial photograph (Figure 3-3) that a large portion of the Shoal Creek Service area is developed, particularly within the City of Griffin limits. Existing Land Use, as shown in Figure 4- 3, is broken down by the drainage area, or subwatershed, of each monitoring station in Figure 5-1, below. This chart shows that there is a high percentage of Residential Development in the Shoal Creek drainage area. There are also significant areas of Commercial, Industrial, and Institutional land uses. Agricultural land exists outside of city limits within the service area. The percentage of impervious area for each subwatershed, as derived from University of Georgia’s GLUT GIS data, is presented in Table 5-3, below. The average percentage of impervious area that is draining to monitoring stations from within the Shoal Creek service area is 17.25 percent. Approximately 17 percent of the land that drains to the monitoring stations lies outside of the service area, and this land has an average impervious area of 6.49 percent. The effects of impervious surface cover resulting from urbanization on various physical and biological stream variables is well documented (Paul and Meyer, 2001). The largest decreases in biological diversity and IBI scores for fish and macroinvertebrates are generally seen between 10% and 25% impervious surface cover. Since most of the Shoal Creek and Heads Creek subwatersheds in Table 5-3 fall in the upper end of this range, it can be assumed that a great deal of stress is being placed on the biotia in these creeks as a result of increased runoff, higher peak discharges, shortened lag times, and habitat degradation that is
48 Shoal Creek Watershed Assessment November 2009 resulting from these hydrologic changes. The Wasp Creek Watershed still has a relatively low percentage of impervious surface coverage, with an estimate of 9 percent impervious within the Shoal Creek service area. Land uses categories on the Future Land Use map (Figure 4-4) are quite different than the categories on the Existing Land Use map (Figure 4-3), which makes a direct comparison difficult. However, future land use predictions for Griffin are detailed in the City of Griffin Comprehensive Plan (City of Griffin, 2004). Based on population projections, it is expected that residential land use will increase by approximately 4% by the year 2024. Industrial, Commercial, and Public/Institutional land uses are also expected to increase to maintain the per capita rate. Transportation/ Communication/ Utility land use will increase at a slower rate than other land uses due to the fact that existing facilities can service increased densities. The parks/ recreation/ conservation land use category is projected to increase in order to maintain the City’s core system of park lands. The future land use plan calls for the expansion of the parks and recreation system primarily through a network of trails and greenways. Based on projections of the additional acreage needed to support anticipated population growth, the remaining undeveloped land in Griffin in 2025 would total 834 acres. In 2004, there was an estimated 1,712 acres of undeveloped land. The City of Griffin has numerous opportunities for infill and redevelopment. The Future Land Use Plan outlined in the City’s Comprehensive Plan encourages mixed-use redevelopment of corridors where public services are currently available. Spalding County, which had a population of 54,117 in 2000, is expected to grow to between 75,900 (low projection) and 103,000 (high projection) residents by 2025 (Spalding County, 2004). It can be expected that some of this growth will occur in unincorporated Spalding County, on the outskirts of Griffin. The Future Land Use map, however, does not indicate any land use changes that would dramatically affect impervious surface coverage or water quality. Much of the county land that drains to the Shoal Creek service area will remain in land uses such as low and medium density residential, agriculture, and forestry. There appear to be some small areas of new Industrial and Commercial development, but the acreage is not extensive. One potentially significant Land Use change that is identified in the Spalding County Comprehensive Plan (Spalding County, 2004), is the addition of an Open Space Network throughout the County, consisting of undeveloped land set aside permanently for common use. This network, which is primarily located along streams, should add some additional protection to surface waters beyond the protection already offered by minimum stream buffer regulations in Spalding County. Areas proposed for Open Space Network in the vicinity of Shoal Creek Service Area are identified in Figure 4-4, and include many linear areas bordering Shoal Creek, Heads Creek and Wasp Creek. Although there will be some growth and development in the Shoal Creek service area between now and 2024, the increase in land required for additional residences, businesses, and public/institutional facilities is not great, and can be accomplished to a large degree through infill and redevelopment, particularly within the City of Griffin. All new development will be required to use stormwater Best Management Practices (BMPs), and comply with regulations concerning development within wetlands and stream buffers. Flows may increase slightly through the addition of some impervious area, but will likely be mitigated through stormwater detention ponds and other BMPs. The City and County also seem committed to the preservation of open space and parkland, particularly in the vicinity of streams. There are no projected land use changes that would be expected to significantly affect sediment, nutrients, fecal coliform, dissolved oxygen, or temperature within the stream systems. Given the scenario presented here, it is expected that land use changes in the Shoal Creek service area will help maintain current water quality and possibly serve to improve it.
49 Shoal Creek Watershed Assessment November 2009
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0% SC0 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SC10 HC1 HC2 HC3 WC1
3500
3000
2500
2000 Acres 1500
1000
500
0 SC0 SC1 SC2 SC3 SC4 SC5 SC6 SC7 SC8 SC10 HC1 HC2 HC3 WC1
Agricultural and Residential (County) Commercial (County) Manufacturing (County) Office/Institutional (County) Residential (County) Central Business District High Density Resid. "A" High Density Resid. "B" Institutional Low Density Resid. "A" Low Density Resid. "B" Low Density Resid. "C" Medium Density Resid. Planned Commercial District Planned Indust. Development Planned Resid. Development Figure 5-1. Existing Land Use by Subwatershed
50 Shoal Creek Watershed Assessment November 2009
Table 5-3. Impervious Area of Monitoring Station Subwatersheds
Subwatershed Percent Impervious SC0 22.36 SC1 22.48 SC2 29.40 SC3 39.29 SC4 34.69 SC5 15.18 SC6 25.26 SC7 27.74 SC8 38.46 SC10 38.07 HC1 42.61 HC2 31.40 HC3 14.85 WC1 9.00
5.3 Biological Analysis
5.3.1 Biological/Habitat Assessment 2000 Habitat conditions were rated “sub-optimal” at the Shoal Creek station being only “partially similar” to the reference site. This actually makes it the most similar in habitat conditions to the references site of the Griffin sample sites. There was, however, obvious impact from sedimentation and silt deposition. Biotic indices (GBP and IBI) rated the Shoal Creek station as having “Very Poor” biotic integrity based on analysis of macro-invertebrate and fish communities. Instantaneous in-situ water quality measurements were generally acceptable for the protection of aquatic life. Most likely, biotic integrity has been greatly influenced by degraded habitat conditions, particularly from sedimentation. No portion of Shoal Creek appears on the 303(d) impaired waters list. However, based on the 2000 biological assessment results, inclusion on the list for “biota impacted” would be justified.
5.3.2 Biological/Habitat Assessment 2004/2005
In the 2004/2005 assessment, the Shoal Creek sites were determined to have marginal (SC0, SC2, SC5 and HC2) to marginal/suboptimal (SC10) physical habitat conditions, with ratings of “dissimilar” (SC0, SC2, SC5 and HC2) and “partially similar” (SC 10) to the reference site based on the habitat scores. The Shoal Creek sites were all categorized as “impaired” based on benthic macroinvertebrate condition, with SC0 and SC5 receiving a “fair” and SC2, SC10, and HC2 receiving “poor” condition ratings. SC2 received a “very poor” fish condition rating, and SC5 receiver a “fair” fish condition rating. Excessive
51 Shoal Creek Watershed Assessment November 2009 erosion and sedimentation were found to be major stressors in the watershed, limiting overall improvement of biological condition.
SC0 - Shoal Creek Mainstem Below Confluence with Southwest Tributary This site is located on Shoal Creek mai nstem just below the confluence with Southwest Tributary downstream of Griffin Country Club Lake. The biological condition received a “fair” rating based on the macroinvertebrate assessment, however, it just made the cut-off between “poor” and “fair” classifications, with a BMI score of 54. This site received the second highest Beck’s BI score (12), indicating the presence of numerous intolerant and moderately intolerant taxa. Three beetle taxa, two scraper taxa, and one swimmer taxon were also present in the sample. The organisms found most often were Rheotanytarsus (Diptera: Chironom idae, tolerance value [t.v.] = 6) and Cheumatopsyche (Trichoptera: Hydropsychidae, t.v. = 5). The physical habitat at this site was rated “dissimilar” (56%). Epifaunal substrate, bank stability, embeddedness, and frequency of riffles all scored low. The presence of a utility clearing along the left bank lowered the riparian score dras tically. Pebble count data at this site indicated that 61% of the channel is composed of fine sedimen ts. SC2 –Shoal Creek Mainstem (Down stream Reach) Located on Shoal Creek approximately 100 m upstream of North Pine Hill Road crossing, this site received a “poor” condition rating based on the macroinvertebrate assessment, with a BMI score of 30. Of the 238 individuals in the subsample, 194 were midges (82%). This site also received a low score for Beck’s BI due to a lack of intolerant taxa present. Polypedilum (t.v. = 6) was the most common organism, comprising 58% of the subsample. For fish condition, this site received a “very poor” (21) rating. Of the seven species collected, two were pollution tolerant, yellow bullhead (Ameiurus natalis) and dixie chub (Semotilus thoreauianus). This site received the lowest scores possible for seven metrics. The IBI score was further reduced due to the proportion of individuals present with external anomalies (6.6%). Physical habitat condition at this site received a “dissimilar” (53%) rating. Bank stability, frequency of riffles, epifaunal substrate, embeddedness, and sedimentation all scored low at this site. Furthermore, 57% of the bottom substrate was comprised of fine sediment. SC5 – Southwest Tributary to Shoal Creek This site is located on Southwest Tributary at the southwest corner of Griffin Country Club, off Westminster Road. Based on the benthic macroinvertebrate community, biological condition was rated as “poor” (43). Eighty-four percent of the individuals found in the subsample were chironomids. Only one scraper taxon and one beetle taxon were present. The most common organism in the subsample was Polypedilum (t.v. = 6). While the benthic macroinvertebrate community was rated on the high end of the “poor” category, fish condition received a “fair” rating. A total of 14 species were present at this site; however, three were pollution tolerant (brown bullhead; Ameiurus nebulosus, yellow bullhead; Ameiurus natalis, and dixie chub; Semotilus thoreauianus). Sensitive species and native suckers were not found at this location. The physical habitat at this site was rated “dissimilar” (55%). Bank stability and vegetative protection scored “very poor” due to the highly incised channel. The proximity of the golf course on the right bank reduced the riparian score significantly. Embeddedness, sediment deposition and epifaunal substrate also scored low. Pebble count data indicate a high proportion of fine sediment (66%) in the stream channel. SC10 - Shoal Creek Mainstem (Upstream Reach)
52 Shoal Creek Watershed Assessment November 2009
Located on Shoal Creek approximately 200 m downstream of Highway 19 crossing, this site received a “very poor” (23) condition rating based on the macroinvertebrate assessment. While the proportion of midges was relatively low (45%), this site had the highest proportion of worms (Oligochaeta) at 9.6%. This site also had one of the lowest scores for Beck’s BI (4). Hydropsyche (Trichoptera: Hydropsychidae, t.v. = 6) and Polypedilum (t.v. = 6) were the most common organisms in the subsample. Physical habitat condition was rated as “partially similar” (60%). Categories that scored low were epifaunal substrate, frequency of riffles, sediment deposition, and embeddedness. Channel flow scored in the high suboptimal range, however, this was likely due to recent heavy rains and may not have been representative of normal baseflow conditions. There was also a dominating presence of trash in the stream, which can be attributed to the proximity of a shopping center upstream where the riparian buffer zone has been replaced with a parking lot. Fine sediments were also shown to dominate the bottom substrate (60%). HC2 – Heads Creek Tributary This site is on Heads Creek Tributary approximately 100 m downstream of Lucky Road crossing. Based on the macroinvertebrate assessment, the biological condition received a “poor” (35) rating. The organisms found most often were Polypedilum (t.v. = 6) and Phaenopspectra (Diptera: Chironomidae, (t.v. = 7). There was a high proportion of chironomids (84%) and oligochaetes (2%) present, and only one swimmer tax and one scraper taxa were represented. Physical habitat condition at this site received a “dissimilar” (52%) rating. Due to the incised nature of the channel, bank stability and bank vegetative protection scored low. Frequency of riffles, epifaunal substrate, embeddedness, and sediment deposition all scored low at this site. Pebble count data indicate that 61% of the bottom substrate was comprised of fine sediment. REF-1 – Britten Creek Reference Site, Meriwether County This site is located on Britten Creek approximately 50 m upstream of Halls Mill Road. Benthic macroinvertebrates were previously sampled and evaluated at this location as part of the CCR, 2000 Biological Assessment, and more recent data from five well-classified reference sites in the Southern Outer Piedmont Ecoregion (Gore et al. 2004) was available for comparison, thus, it was not necessary to sample them at this location. Results of fish community sampling produced a “good” (50) rating. Sixteen species, including two sensitive species (highscale shiner; Notropis hypsilepis, and spotted sucker; Minytrema melanops) were present. Seven metrics received the highest possible scores and the rest scored in the middle range. All physical habitat parameters were ranked as optimal or in the upper suboptimal category. This site had an overall physical habitat score of 169 out of 200 maximum points.
5.3.3 Biological/Habitat Assessment 2008/2009 In the 2008/2009 assessment, the Shoal Creek sites were determined to have marginal (SC0, SC5 and HC2), marginal/suboptimal (SC2), and suboptimal (SC10) ecological conditions based on the habitat scores. All Shoal Creek sites received a biological condition rating of “poor” based on BMI index scores. SC2 received a “very poor” fish condition rating and SC5 received a “fair” fish condition rating.
53 Shoal Creek Watershed Assessment November 2009
5.3.4 Biological/Habitat Summary The same sites assessed during the 2008/2009 study were also assessed/monitored in 2004/2005. In order to evaluate long-term trends at these sites, it is critical to compare the original data with the current data. A summary of the physical habitat, benthic macroinvertebrate, and fish community assessments is presented in Table 5-4. Habitat assessment scores are comparable between the studies. The habitat score increased at SC2 by 21 points (24% increase) and increased at SC10 by 21.5 points (21% increase), indicating a slight improvement in ecological condition at these sites. The habitat score decreased at site HC2 by 21.5 points (22% decrease). There appears to have been little to no change at SC0 and SC5, which had very similar habitat assessment scores for both studies. Some of the scoring differences may be due to changes in scorers (different individuals from the original study) and in habitat assessment forms used (protocol/habitat assessment forms changed slightly from 2005 to 2009). In 2006, new BMI metrics were developed by the GA DNR for Southern Outer Piedmont Subecoregion (45b). Macroinvertebrate data from 2004/2005 was re-analyzed and scored using the 2008/2009 metrics. This conversion allowed for an equitable comparison between the two studies/datasets. Using the converted 2004/2005 data, all sites showed a decrease in BMI scores of at least 10% from 2004/2005 to 2008/2009, with sites SC0 and SC5 dropping into the Poor category, and the other sites remaining in the Poor category. Again, some of the changes may be attributed to changes in the GA DNR/EPD protocol in the intervening years, but these changes should be minor since the data were re-scored and reanalyzed. Finally, fish community conditions did not appear to change much between the studies. The IBI integrity rating is Very Poor at site SC2 and Fair at site SC5 for both studies. Analysis of 2008/2009 fish data differed slightly from analysis of 2004/2005 data in that some of the metrics used to calculate the FIBI index score are not the same between the two assessments due to the updated Georgia FIBI protocols. Nine of the thirteen metrics are generally comparable between the two protocols, and scores for those metrics are presented in Table 5-5 for comparison. The scores for these metrics are similar between the 2005 and the 2009 assessments, supporting the conclusion that the fish community did not change much between the studies.
Table 5-4. Summary of Biological Assessments
Station Assessment Habitat BMI IBI
Ecological Index Narrative Taxa Score Condition Score Condition Score/Rating Richness SC0 2008/2009 95.5 Marginal 31 Poor N/A N/A 2004/2005 94 Marginal 35 Fair N/A N/A SC2 2008/2009 110 Marginal/Suboptimal 20 Poor 20/Very Poor 8 2004/2005 89 Marginal 25 Poor 22/Very Poor 7 SC5 2008/2009 86 Marginal 22 Poor 38/Fair 13 2004/2005 93 Marginal 37 Fair 38/Fair 14 SC10 2008/2009 123.5 Suboptimal 20 Poor N/A N/A 2004/2005 102 Marginal/Suboptimal 24 Poor N/A N/A HC2 2008/2009 68.5 Marginal 18 Poor N/A N/A 2004/2005 88 Marginal 28 Poor N/A N/A * 2004/2005 BMI scores in this table have been recalculated using metrics from the 2008/2009 study
54 Shoal Creek Watershed Assessment November 2009
Table 5-5. Scores for Comparable FIBI Metrics from 2005 to 2009 Assessments
SC2 Value Metrics (Score) SC5 Value (Score)
2009 Metric/2005 Metric 2009 2005 2009 2005
Number of Native Fish Species/ Number of Native Fish Species 8(1) 7(1) 13(3) 14(5)
Number of Benthic Invertivore Species/ Number of Benthic Invertivore Species 0(1) 0(0) 2(5) 1(3)
Number of Lepomis Species/ Number of Native Sunfish Species 3(5) 3(5) 2(3) 3(5)
Number of Native Round-Bodied Sucker Species/ Number of Native Sucker Species 0(1) 0(1) 0(1) 0(1)
Number of Sensitive Species/ Number of Sensitive Species 0(1) 0(1) 1(1) 0(1)
Evenness/ Evenness 78.5%(5) 64%(3) 65.1% (3) 60%(3)
Proportion of Generalist Feeders and Herbivores/ Proportion of Omnivores 46.7%(1) 0%(5) 33.1%(3) 14%(3)
Proportion of Individuals as Insectivorous Cyprinids/ Proportion of Individuals as Insectivorous Cyprinids 0%(1) 0%(1) 59.7%(5) 60%(5)
Proportion of Indiiduals with DELT Anomalies/ Proportion of Individuals with External Anomalies 0%(0) 7%(-4) 0%(0) 1%(0)
55 Shoal Creek Watershed Assessment November 2009
6 Constituents & Areas of Concern
Shoal Creek and its tributaries are experiencing ecological degradation that is typical of urban watersheds. The streams have been affected directly through channelization, and indirectly through changes in surrounding land use and the resulting changes in volume, velocity, and quality of stormwater runoff. These alterations to the land also lead to increased instream bank erosion. As noted in the Geomorphic Assessment, there are several areas of severe erosion along the ma in reach of Shoal Creek and its tributaries, including a large headcut that could migrate upstream and eventually cause the upstream dam to fail (Site 43 on Map 3 of Appendix C). The percent of impervious area in the service area wat ershed is approximately 17.25 percent. This high percentage of impervious surface cover can be expected to result in hydrologic conditions and ensuing habitat conditions that only allow the survival of the most tolerant aquatic organisms. Pollutants Water quality analysis reveals that state water quality standards are being violated based on biota, DO, pH, and fecal coliform. Impaired biota is indicated by a “Very Poor” IBI score for fish at site SC2. Standards for pH were violated as indicated by individual measure ments less than 6.0 at sites SC4, SC7, HC1, and HC2. DO standards were violated as indicated by an average DO concentration less than 5.0 mg/L at site SC1, and individual measurements less than 4.0 mg/L a t sites SC 1, SC7, SC 8, HC2, a nd SC0. Fecal coliform standards were violated based on an individual measurement greater than 4,000 colonies/100 mL at site SC10 during winter months, an average feca l coliform count that exceeded 1000 colonies/100 mL at site SC10 during winter months, and average fecal coliform counts that exceeded 200 colonies/100 mL for all sites except for SC1 during summer months. Also of some concern with regards to water quality are the occasional high concentrations of phosphorus and total Kjeldahl nitrogen at various sites throughout the service area. The presence of zinc and copper throughout the watershed is a potential concern. Copper and zinc are toxic to aquatic o rganisms w hen they are present at high enough concentrations. Lastly, there is some concern about the detection of lead in the sediment at sample site SC8 in 2003. The measured concentration was above the TEC concentration, but below the PEC concentration. Neither Shoal Creek nor Heads Creek are on EPA’s 303(d) list of impaired streams for those portions of the streams that are within or just downstream of the Shoal Creek service area; however, based on the findings of this assessment, both Shoal Creek and Heads Creek have, at certain points in time, qualified for impairment based on pH, DO, and fecal coliform, and Shoal Creek would be qualified for biota impairment for the designated use of Fishing. Once hardness data is collected in this watershed, the dissolved fractions of copper and zinc can be calculated to determine whether or not state toxicity standards are being violated. Sources Non-point source pollution is likely responsible for all of the water quality impairments in the Shoal Creek Service area watershed. Most of the pollutants were only present at elevated levels on rare occasions, and the elevated levels were seen at locations throughout the watershed. A potential cause of the consistently low DO at site SC1 may be the Griffin Country Club Lake that is directly upstream. Monitoring at this site ended in 2004, but site SC0, which is located in essentially the same place, has had low DO measurements in 2007, 2008, and 2009. Fecal coliform appears to be a problem that is ubiquitous in the watershed. Given the high percent of residential land that drains into Shoal Creek and Heads Creek, pet waste is certainly contributing to this problem, and could potentially be the primary source of fecal coliform bacteria. Zinc and copper are likely originating from roadways through the use of automobiles.
56 Shoal Creek Watershed Assessment November 2009
Initial Ideas for Watershed Management and Protection To address the impaired biota and water quality in the Shoal Creek service area, it will be necessary to examine the ways that non-point source pollution is entering the surface waters. It is important that stormwater Best Management Practices are appropriately selected and implemented at strategic locations throughout the watershed. The focus should be on reducing flows, and providing and maintaining appropriate sediment and erosion control features. This will have a significant influence on the long-term condition of surface waters in the Shoal Creek service area, and the waters downstream. It would also be advantageous for the City of Griffin to identify the source of fecal coliform bacteria in the Shoal Creek watershed, similar to the Bacterial Identification Study done for Potato Creek.
57 Shoal Creek Watershed Assessment November 2009
7 References
City of Griffin. 2004. City of Griffin 2024 Comprehensive Plan. Georgia Department of Natural Resources (GA DNR ) 1999. (draft) Standard Operating Procedures: Freshwater Macroinvertebrate Biological Assessment. Georgia Department of Natural Resources, Water Protection Branch. Atlanta, GA. Georgia Department of Natural Resources (GA DNR). 2000 (draft). Standard Operating Procedures for Conducting Biomonitoring on Fish Communities in the Piedmont Ecoregion of Georgia. Georgia Department of Natural Resources, Wildlife Resources Division, Fisheries Section. Georgia Department of Natural Resources (GA DNR ). 2004. Watershed Assessment and Protection Plan Guidance Phase II. Watershed Assessments. Georgia Department of Natural Resources, Environmental Protection Division. Georgia Department of Natural Resources (GA DNR ). 2005a. Watershed Assessment and Protection Plan Guidance Phase I. Watershed Monitoring Plans. Georgia Department of Natural Resources, Environmental Protection Division. Georgia Department of Natural Resources (GA DNR ). 2005b. Part 1: Standard Operating Procedures for Conducting Biomonitoring on Fish Communities in Wadeable Streams in Georgia. Georgia Department of Natural Resources, Wildlife Resources Division, Fisheries Management Section. Georgia Department of Natural Resources (GA DNR ). 2007. Macroinvertebrate Biological Assessment of Wadeable Streams in Georgia: Standard Operating Procedures. Georgia Department of Natural Resources, Environmental Protection Division, Watershed Protection Branch. Atlanta, GA. Georgia Department of Natural Resources (GA DNR ). 2009. Georgia Rare Species and Natural Community Information. http://www.georgiawildlife.org/documentdetail.aspx?docid=89&pageid=1&category=conservation Georgia Environmental Protection Division (GA EPD). 2004 (draft). Standard Operating Procedures: Freshwater Macroinvertebrate Biological Assessment. Gore, J.A., J.R. Olsen, D.L. Hughes, and P.M. Brossett. 2004 (draft). Reference conditions for wadeable streams in Georgia with a multimetric index for the bioassessment and discrimination of reference and impaired streams. Ecoregion Reference Site Project. Phase 1. Final Report. Columbus State University, Columbus, GA. Griffith, G.E., J.M. Omernik, T. Foster, and J.A. Comstock. 2001. Ecoregions of Georgia. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Corvallis, OR. Lee, G.F. and Jones-Lee, A. 2000. “Regulating Copper in Urban Stormwater Runoff,” Timely Topics, NorCal SETAC News 11:(No 2) 10-11, June (2000) MacDonald, D. D. , C. G. Ingersoll and T. A. Berger. 2000. Development and Evaluation of Consensus- Based Sediment Quality Guidelines for Freshwater Ecosystems. Archives of Environmental Contamination and Toxicology. 39(1): 20-31. Mitchel, Mark and William Stapp. 1994. Field Manual for Water Quality Monitoring - An Environmental Education Program for Schools. Muller, David K. and Dennis R. Helsel. 1996. U.S. Geological Survey Circular 1136- Nutrients in the Nation's Waters--Too Much of a Good Thing?
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Paul, Michael J. and Judy L. Meyer. 2001. Streams in the Urban Landscape. Annual Review of Ecology and Systematics. 32:333-65. Paragon Consulting Group. 2003. Section 319(h) Non-point Source Pollution Control Program, Watershed Protection Final Report, City of Griffin, North Griffin Drainage Basin. Platkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M. Hughes. 1989. Rapid Bioassessment Protocols for Use in Streams and Rivers: Benthic Macroinvertebrates and Fish. EPA/444/4-89-001. U.S. EPA, Assessment and Watershed Protection Division, Washington, D.C. Philips, L., J. E. Erik, and M.B. McLeod. 2001. City of Griffin Stream Bank Restoration Program. Proceedings of the 2001 Georgia Water Resources Conference. Southeast Regional Climate Center (SRCC). 2007. Experiment, Georgia (station 093271), period of record: 6/1/1900 to 6/30/2004. Retrieved 4 Aug. 2009
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