Category: Research Sponsored by GWRI

The FY 2012 state funding (104B) provided to the Georgia Water Resources Institute from the United States Geological Survey through the National Institutes for Water Resources was used to support critical research needs, graduate education, and information dissemination in the State of Georgia. The following projects were funded as part of the program:

1. Impact of Upstream Water Use on Salinity and Ecology of Apalachicola Bay; P. Roberts; Georgia Institute of Technology.
2. Monitoring Diurnal and Seasonal Cycle of Evapotranspiration over Georgia using Remote Sensing Observations; J. Wang; Georgia Institute of Technology.

The FY 2011 state funding (104B) provided to the Georgia Water Resources Institute from the United States Geological Survey through the National Institutes for Water Resources was used to support critical research needs, graduate education, and information dissemination in the State of Georgia. Four sub‐grants supported the following projects:

1. Flood Risk and Homeowners’ Flood Risk Perceptions: Evidence from Property Prices in Georgia; S. Ferreira; University of Georgia
2. Assessment of endocrine disruption in fish and estrogenic potency of waters in Georgia; R. Bringolf, C. Jennings, J. Zuiderveen; University of Georgia and Columbus State University.
3. Impact of Upstream Water Use on Salinity and Ecology of Apalachicola Bay; P. Roberts; Georgia Institute of Technology.

Additionally, GWRI co-sponsored the Georgia Water Resources Conference held in April 2011.

The FY 2008- FY 2010 state funding (104B) provided to the Georgia Water Resources Institute from the United States Geological Survey through the National Institutes for Water Resources was used to support critical research needs, graduate education, and information dissemination in the State of Georgia.

The research projects supported during this time span can be found in the three year Evaluation Report.

Principal Investigator: Boris Mizaikoff (Georgia Tech)

Sponsor: GWRI
Start Date: 2002-09-01; Completion Date: 2004-09-01;
Keywords: Water Quality, Surface Water, Toxic Substances

Problem and Research Objective:

Increasing pollution of water resources has stimulated the development of sensor systems capable of screening organic pollutants in the aquatic environment. Especially in urban areas, increasing concentration of volatile organic compounds in surface and ground water threaten primary sources of drinking water. Hence, there is a substantial demand for in-situ, continuously operating and reliable analysis methods emphasizing selective determination of abundant pollutants, such as chlorinated hydrocarbons (CHCs), pesticides or the broad class of endocrine disrupting compounds (EDCs).

The main goal of this research project is the optimization, application and validation of infrared chemical sensor systems for the determination of organic pollutants such as chlorinated hydrocarbons, pesticides or endocrine disrupting compounds in the Rottenwood Creek stream, an urban stream located in the metro Atlanta area. This stream is affected by residential, commercial and industrial land use. Synthetic sensing interfaces (‘biomimetics’) based on sol-gels and imprinted polymers emphasizing selective analyte recognition will be combined with existing infrared sensor systems already established by our research group. Following optimization of the instrument in the laboratory and validation with real-world samples, measurements at Rottenwood Creek are envisaged as representative example of an urbanized water resource.

Principal Investigator: Seth Rose (Georgia State University)

Sponsor: GWRI
Start Date: 2003-03-01; Completion Date: 2004-02-28;
Keywords: Base Flow, Isotope Hydrology, Georgia Piedmont Watersheds, Middle Oconee River basin, Age-dating of water

Abstract:

The proposed research addresses the scale problem in surface water hydrology; specifically it focuses upon using isotope and geochemical tracers to assess the effects of basin scale upon base flow generation. It is expected that the temporal and spatial varitions with respect to major ion concentrations, stable oxygen and strontium isotope ratios, environmental tritium concentrations will reveal useful information pertaining to how recharge is eventually processed as base flow within Piedmont Province watersheds. The key question is whether the contribution of water to a large watershed comes solely from small watersheds (i.e. local flow systems) or whether a regional flow system transports base flow to higher order Piedmont streams. The investigation of seasonal isotopic variability of base flow on different spatial scales along with rainfall and shallow ground water should provide a wealth of interpretable data that can be used to address this question. The proposed utilization of strontium isotope ratios (a tracer of the lithogenic contribution to water chemistry)likely represents the first such study of its kind in this setting. The proposed study area is the Middle Oconee River basin which is located in a relatively underdeveloped region between Atlanta and Athens, Georgia.

Principal Investigator: Stuart Pocknee (University of Georgia)
Principal Investigator: Calvin Perry (University of Georgia)
Principal Investigator: Craig Kvien (University of Georgia)
Principal Investigator: George Vellidis (University of Georgia)

Abstract:

Agricultural water use is a major portion of total water consumed in many critical regions of Georgia. Georgia has over 9000 center pivot systems, watering about 1.1 million acres (445,000 ha). Many fields irrigated by these systems have highly variable soils with areas ranging from very sandy to very heavy as well as non-cropped areas. Current irrigation systems are not capable of varying the water application rate to meet the needs of plants on different soil types nor capable of stopping application in non-cropped inclusions. This limitation results in over-applying or under-applying irrigation water. In addition, five years of drought and a lawsuit over Georgia water use by Florida and Alabama have prompted a renewed interest in water conservation methods by the general public, which is becoming increasingly insistent that agriculture do it’s part in conserving water.

The University of Georgia / NESPAL Precision Ag Team has developed a prototype method for differentially applying irrigation water to match the precise needs of individual sub-field zones. Recognizing that water is the major yield determiner in nearly all agricultural settings, the original interest lay in varying application rates from a precision crop production viewpoint. However, it was quickly apparent that a method for varying irrigation across a field could also lead to substantial water savings. The method is referred to as Variable-Rate Irrigation (VRI). This system easily retrofits onto existing center pivot irrigation systems.

This research is expected to accomplish the following:
To complete the development of the VRI system that will enable growers to conserve irrigation water while enhancing profitability – both accomplished through site-specific water management. To gather needed application data to verify uniform and variable application rates are being achieved. To gather data needed to verify calculated water savings are being achieved and yields are being enhanced. To gather the economic information needed to effectively manage and justify such variable-rate systems.

Sponsor: GWRI
Start Date: 2003-03-01; Completion Date: 2004-02-28;
Keywords: irrigation management, water use efficiency, agriculture

Principal Investigator: Kevin H. Barnes (University of Georgia)
Principal Investigator: Byron J. Freeman (University of Georgia)

Sponsor: GWRI
Start Date: 1996-04-01; Completion Date: 1996-04-01;
Keywords: suspended sediment, NTU, TSS, fish, biodiversity

Description:

Excessive sedimentation and high levels of turbidity threaten the native fish species of Georgia by destroying habitat and by impairing fish feeding and spawning. To propose water quality standards for suspended sediments that would be protective of Georgia’s diverse freshwater fish fauna (283 spp.), we have searched existing records of suspended sediment concentrations (measured as turbidity in NTUs) and fish collections taken throughout rivers and streams in Georgia. We focused our attention on rivers and streams above the fall line, where the greatest number of threatened fish species are found and where excessive sedimentation is the greatest problem. We searched 36 years of water quality data and over 20,000 records of fish collections in Georgia. Only 0 – 8% of the sediment sampling stations in four major river basins in this part of the state (Mobile, Apalachicola-Chattahoochee-Flint, Altamaha, and Tennessee) have contemporaneous fish and sediment data. Hence we conclude that adequate measures of suspended sediment are lacking in areas of high fish diversity, and therefore field work in representative basins is needed to test the proposed relationships between suspended sediments and fish diversity that we developed from this very limited data base.We analyzed the existing fish and sediment data by examining the percentage of suspended sediment samples that exceed 25, 50, and 100 NTU and by comparing the feeding and spawning guilds of fishes at sites with different exceedence characteristics. We then used these data to hypothesize suspended sediment regimes that would be protective of the native fish assemblages. Based on fish and sediment data from Yellow River and Falling Creek, we hypothesize that in the Piedmont physiographic province, native fishes would be protected if random monthly samples of turbidity never exceed 100 NTU, if less than 5% of samples exceed 50 NTU, and if less than 20% of samples exceed 25 NTU. Based on fish and sediment data from three sites in the Conasauga River, we hypothesize that in the Ridge and Valley physiographic province, native fishes would be protected if monthly random samples of turbidity never exceed 25 NTU. These more stringent standards appear necessary because of the nature of the sediments in this physiographic province and because of the vulnerability of the fishes in this region to sedimentation. These hypotheses require field testing.

Principal Investigator: Terry W. Sturm (Georgia Tech)

Sponsor: GWRI
Start Date: 2003-03-01; Completion Date: 2004-02-28;
Keywords: fluid flow, hydraulics, instream flow, river beds, rivers, sedimentation, sediment load, sediment TMDL, nonpoint pollution, urban hydrology

Abstract:

Sediment loads and water quality are inextricably linked in Georgia streams, particularly in urban areas in the piedmont region where fine-grained sediments contribute turbidity in the water column and deposition in downstream areas. Urbanization results in increased washload to the stream due to runoff from construction sites that are inadequately protected by erosion control measures. In addition, the runoff volume and peak discharge increase due to an increase in impervious area on the watershed. The result is a loss of equilibrium in the sediment regime of the stream. The consequences include bank erosion, degradation, loss of aquatic habitat and spawning areas, inhibition of photosynthesis due to turbidity in the water column, increased water treatment costs, loss of reservoir storage capacity, and transport of contaminants associated with fine sediments. The resulting impairment of water quality has to be addressed with respect to compliance with section 303(d) of the Clean Water Act. In particular, where excess sediment loads threaten the biological integrity of streams, TMDLs (total maximum daily loads) must be established to quantify allowable sediment loads for the purpose of controlling the sources of water quality impairment. The development of TMDLs for sediment is complex because of various in-stream processes that contribute to the problem as well as watershed sources of sediment. The objectives of the proposed research are to develop a procedure for: (1) measuring sediment loads in streams due to both watershed sediment yield and in-stream processes; and (2) evaluating the contribution of in-stream processes such as bed and bank erosion to the sediment budget of stream reaches selected for establishment of TMDLs. The objectives will be achieved through a combination of field measurements on an urban stream and numerical modeling of sediment loads and stream stability.

Principal Investigator: Paul Work (GTREP – Savannah)

Sponsor: GWRI
Start Date: 2002-03-01; Completion Date: 2003-02-28;
Keywords: Sediment, Non Point Pollution, Surface Water

Description:

This report discusses the techniques for data collection in Hartwell Lake and presents the analyzed data. Three types of data were collected in Hartwell Lake between February 10th and February 13th, 2003: bathymetry, velocity and shoreline position data. Depth data were collected using a dual frequency depth measuring system. Velocity data were measured using a 1200 kHz Acoustic Doppler Current Profiler (ADCP), and shoreline data were provided by a differential global positioning system (GPS). During the bathymetric surveys and velocity measurements a handheld GPS was also integrated with the devices for navigation.

Comparison of bathymetric surveys to previous surveys provided by USACE indicated approximately 2  0.27 meters of deposition over 40 years within the thalweg.

The hydrodynamics of the lake were modeled using a numerical model previously. In this study, surface velocities are measured in the main pool of the lake to validate results of the numerical model. Strong winds (more than 4 times the historical average) from the southwest were observed during the measurement period. Maximum measured surface velocities at several transects were ~50 cm/s and average velocities were ~25 cm/s.

Principal Investigator: Judith Meyer (University of Georgia)

Sponsor: GWRI
Start Date: 2001-03-01; Completion Date: 2002-02-28;
Keywords: Ecosystem processes, Basin-wide analysis for water management, Solute transport, Flow regime, Apalachicola-Chattahoochee-Flint River Basin

Problem and Research Objectives:

The quantity and timing of river flow is critical to the ecological integrity of river systems (Poff et al.1997). Flow is strongly correlated with physical and chemical characteristics of the river such as channel shape, water temperature and velocity,and habitat type and complexity (Jowett and Duncan 1990,Poff et al.1997). Five main components of the flow regime impact ecological processes:magnitude of discharge at critical time periods,frequency of the various discharge magnitudes,duration of time associated with a particular discharge,timing or predictability of discharge events of particular magnitudes,and the rate of change of hydrologic conditions (Richter et al. 1996,Poff et al.1997) .These five components of the flow regime influence the ecological dynamics of river systems directly and indirectly by affecting water quality, energy sources,physical habitat,and biotic interactions (Karr 1991,Poff et al.1997).

Although there are many different types of hydrologic and channel alterations that result in changes to the flow regime,dams are one of the most conspicuous and prevalent forms of flow alteration on large and some smaller rivers and streams.In the contiguous United States,there are only 42 rivers with greater than 200 river kilometers unregulated by major dams (Benke 1990).Though there have been a number of studies of the impacts of dams on channel morphology (Ligon et al.1995),fish (Moyle et al.1998), habitat availability (Bogan 1993),and riparian species survival and recruitment (Rood et al.1995),less is known about the impact of dams and flow regime on basic ecosystem processes such as nutrient uptake and metabolism,especially in larger rivers.In many cases,these ecosystem processes are directly linked to the ecosystem services (e.g.water supply,pollution control, and fisheries)expected from the river system.

We are studying the relationship between flow and nutrient uptake and metabolism on the Chattahoochee River below Atlanta.The fixation of energy through primary production and the subsequent release through respiration are primary ecosystem functions,and the addition or loss of energy to the system can influence energy flows in downstream systems.In order to determine net addition or loss of energy to the system, net daily metabolism can be calculated.Net daily metabolism is defined as the difference between gross primary productivity and total system respiration (Bott 1996). Metabolism has been shown to vary with high stream discharge as a result of shifts in primary production (Uehlinger and Naegeli 1998).However,relationships between net daily metabolism and low flow conditions are uncertain,particularly in large river systems.

The uptake and processing of nutrients by rivers is essential to maintaining downstream and instream water quality.In unregulated rivers,the downstream ecosystems that could be affected by high nutrient loadings are typically estuaries. However,in regulated rivers,there are typically a series of reservoirs that are connected by sections of flowing water.This is the situation on the Chattahoochee River.In addition,the flowing river section between Lake Lanier and West Point Lake receives approximately 220 million gallons a day of wastewater treatment plant effluent (Frick et al.1996).The retention and transformation of the nutrients associated with these inputs is essential to maintaining water quality in this section of the river and in West Point Lake.Nutrient uptake length is the length of stream traveled by the average nutrient molecule in the water column before being taken up by biota (Stream Solute Workshop 1990).Nutrient uptake lengths in small streams is related to discharge (Stream Solute Workshop 1990).Uptake lengths in streams receiving wastewater treatment plant effluent are typically much longer than uptake lengths in streams with similar discharge but no wastewater inputs (Marti et al.In press).However,it is uncertain how nutrient uptake lengths vary with low flows in large rivers.

Our objectives were to determine how net ecosystem metabolism and nutrient uptake lengths vary with discharge under baseflow conditions in the Chattahoochee River below Atlanta.In addition,we wanted to determine the importance other factors that may influence metabolism and nutrient uptake such as temperature,total suspended solids,light,dissolved organic carbon,water column chlorophyll a concentrations,and nutrient concentrations.We hope that these analyses will help to give a better understanding of how flow regime influences ecosystem processes in a regulated river.