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Georgia Water Resources Conference
Georgia Water Resources Conference
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ItemThe impact of on-site wastewater treatment systems on the nitrogen load and baseflow in urbanizing watersheds of Metropolitan Atlanta, Georgia(Georgia Institute of Technology, 2013-04) Oliver, C. ; Risse, L. Mark ; Radcliffe, David E. ; Habteselassie, M. ; Clarke, John S.On-site wastewater treatment systems (OWTSs) are widely used in the Southeastern United States for municipal wastewater treatment. As urban and suburban populations increase, the use of OWTSs is expected to further increase. This region heavily depends on surface waters for its water supply, therefore, the impact of OWTSs on surface water quality and quantity must be investigated. Conventional OWTSs can be potential sources of N pollution for groundwater and streams that can cause human health concerns and stimulate algal growth resulting in eutrophication. The overall goal of this project is to determine the impact of OWTSs on the N load and baseflow in urbanizing watersheds of Ocmulgee and Oconee River basins in Georgia. This paper presents preliminary results of the differences in the N load and baseflow as well as other water quality indicators such as electrical conductivity (EC) and chloride (Cl-) in streams of watersheds impacted by high (HD) and low density (LD) OWTSs. Synoptic samples and discharge measurements of 24 watersheds were taken 3 times per year in fall, spring, and summer under baseflow conditions. EC and Cl- concentrations were significantly higher in HD OWTS watersheds for all three sampling events. N concentrations were not statistically different between HD and LD watersheds for all three sampling events. Baseflow measurements in the fall and spring were not statistically different between HD and LD watersheds, but summer measurements were significantly higher in the HD watersheds. The results indicate the presence of OWTS effluent in streams of watersheds with HD OWTSs, while N analysis indicates a reduction in concentration through dilution and denitrification. However, increased baseflow in watersheds impacted by HD OWTSs results in an increase in total N load. Further analysis is needed to accurately determine and quantify the impact of OWTSs on water quality and quantity at the watershed-scale.
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ItemPhosphorus and Sediment in Headwater Streams Draining Poultry Operations in the Upper Etowah River Basin, Georgia(Georgia Institute of Technology, 2007-03) Romeis, Josh ; Jackson, C. Rhett ; Radcliffe, David E. ; Risse, L. Mark ; Bryant, J.A 1.5-year monitoring program was initiated in January 2005 to support a University of Georgia study aimed at evaluating nutrient trading opportunities for phosphorus (P) in the upper Etowah River basin in Georgia. Twelve first-order streams were instrumented with hydrologic monitoring equipment and automated samplers. Nine streams drain agricultural (AG) watersheds predominated by poultry operations but different in terms of land use history, best management practices, soil test P (STP) concentrations, and other factors. Three streams drain forested (FORS) watersheds. The monitoring program consisted of biweekly grab sampling coupled with stormchasing. From preliminary results, median low-flow and stormflow concentrations of total P (TP) in astreams were 0-1 and 1-3 orders of magnitude greater, respectively, than in FORS streams. The 3 highest median stormflow TP concentrations in AG streams were observed where 3 of the 4 highest STP concentrations were observed. Median low-flow total suspended solids (TSS) concentrations in AG streams were 0-1 order of magnitude greater than in forested streams. Median stormflow concentrations of TSS between the two land use types were within the same order of magnitude. Streamflow, STP, event mean concentrations, and other variables may be important for estimating P loads from agricultural watersheds monitored for the study.
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ItemModeling Phosphorus Loading to Lake Allatoona: Implications for Water Quality Trading(Georgia Institute of Technology, 2007-03) Radcliffe, David E. ; Lin, Z. ; Risse, L. MarkLake Allatoona, a large reservoir north of Atlanta Georgia that drains an area of about 2870 km2, is threatened by excessive algal growth and scheduled for a phosphorus (P) TMDL. In this paper, we use the Soil Water Assessment Tool (SWAT) computer model to estimate the total P load to Lake Allatoona during the periods 1992-1996 and 2001-2004. We also use the model to estimate the contribution from different sources in the watershed. The total P load to Lake Allatoona increased by 20% between the two time periods. The contribution from point sources decreased from 30% to 13% of the total load due to permit restrictions on P for poultry processing plants. The largest nonpoint source of P was estimated to be forest land use in 1992-1996 accounting for 31% of the load and urban land use in 2001-2004 accounting for 50% of the load. Poultry/cattle land use accounted for 18% in 1992-1996 and 15% in 2001-2004. The implications for a program to trade P credits are: 1) point sources and poultry/cattle operations account for similar percentages of the current load, 2) urban development accounts for most of the current P load and should be brought into a trading program, 3) poultry processing plants that have not upgraded to better P removal technology might trade their current load to wastewater treatment facilities that accept their wastewater, 4) cattle in streams and row crops are not large sources according to our model, and 5) there is little net loss of P to streams during transport to Lake Allatoona so distance of a source from the lake may not be important in a trading scheme.
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ItemLand use effects on suspended sediment yield in six small Georgia watersheds(Georgia Institute of Technology, 2005-04) Bradshaw, J. Kenneth ; Radcliffe, David E. ; Lichtenstein, Karin ; Bakker, Mark ; Jackson, Rhett ; Markewitz, Daniel ; Risse, L. MarkIn Georgia, over 600 stream segments are scheduled for TMDL development due designated use. Seventy-seven stream segments are listed for excessive sediment. The state does not have quantitative standards for the regulation of sediment concentration. The development of sediment yields using appropriate reference streams with minimum development may be a way to determine what the maximum daily sediment loading should be for impaired streams. This study was initiated to compare water quality in six streams with differing land use. This paper focuses on suspended sediment comparisons among the six streams. Two streams drain areas that are entirely forested and these represent reference streams for the purpose of this study. Two streams drain areas that are predominately agricultural (one dairy and the other a combination of poultry and cattle), and two streams drain areas that are in subdivisions with septic systems. Suspended sediment concentrations (SSC) and stream stage were measured during base flow and storm flow conditions. Annual sediment and water yields were calculated and for each stream for the years 2003 and 2004. Average SSC ranged from 155 to 720 mg/L and was lowest in one of the forested steams and highest in the dairy stream. Sediment yield ranged from 0.91 to 10.11 Mg/ha/yr and was lowest in one of the forested steams and highest in the dairy stream. In general, the forested streams had the lowest sediment yields, the agricultural watersheds had the highest sediment yields, and the suburban streams were intermediate.
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ItemAWARE Team Activities in Georgia(Georgia Institute of Technology, 1999-03) Risse, L. Mark ; Radcliffe, David E. ; Harris, Glen ; Newton, G. Larry ; Worley, John ; Cabrera, Miguel L.This paper will discuss the development of the AWARE (Animal Waste Awareness in Research in Extension) team and some of its recent activities. It will cover the goals of the team and how it functions to obtain these goals. It will also discuss some of the tools the team uses including the webpage, listserve, and meetings and discuss how they are helping people throughout the state with information exchange on animal waste management issues. It will also discuss some of the AWARE teams past activities and plans for future activities.
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ItemRole of a Stakeholder Advisory Group in Developing C.A.F.O. Regulations in Georgia(Georgia Institute of Technology, 1999-03) Radcliffe, David E. ; Risse, L. Mark ; Thompson,JustineIn June, 1998 the State Environmental Protection Division (EPD) convened a group of approximately 90 stakeholders with an interest in regulations for concentrated animal feeding operations (CAFO's). The members represented public interest groups, producers, academia, and state and federal agencies. They were asked to consider revisions to the current requirements for National Pollution Discharge Elimination System (NPDES) permits for CAFO's and the creation of several size categories with escalating requirements. Currently permits are required for animal feeding operations with more than 1,000 animal units (AU) and a wet manure system. Four subcommittees were formed consisting of 12-14 members each: 1) size classification and regulatory system, 2) location restrictions, odors, and setbacks, 3) nutrient management and monitoring, and 4) design and administration. There was consensus to require nutrient management plans, training and certification of operators, and riparian buffers for operations larger than 300 AU. There was no consensus on whether a smaller size category starting at 100 AU should be required to register, or a large category starting at 2,000 AU should require more stringent measures. There was agreement for location restrictions for recharge areas, deep sands and wet soils, endangered species habitat, the 11 counties of Coastal Management Area, impaired streams, and wild and scenic rivers.