Category: Research Sponsored by GWRI

Principal Investigator: Yoko Parmelee (The University Of Georgia)
Principal Investigator: Jackie Sellers (University of Georgia)
Principal Investigator: Ronald M. North (University of Georgia)
Principal Investigator: Hubert A. Pless (The University Of Georgia)

Sponsor: GWRI
Start Date: 1986-06-01; Completion Date: 1986-06-01;
Keywords: financing, pricing, user charges, cost sharing, financial feasibility, economic cost, water rates, repayment, demand, benefit cost analysis, cost allocation, water rights, tariff, market value, water policy.

Description:
As appropriated Federal funds for water resources projects, programs, and services decline the funding needs must be made up by state and local governments and/or by the private sector businesses and consumers. As the responsibility for infrastructure moves to the private sector it is essential for economic efficiency and financial feasibility to price water services at their full cost or at a price that reflects their value to consumers and users in a manner that covers at least the full cost. For all of the flow services produced by water (supply, waste treatment, hydropower), a two part tariff is recommended to reflect a capacity charge and a commodity charge. Tariffs should be set to reflect the high fixed cost of service and to reflect user willingness to pay for essential services. The excess revenue may be used to provide for welfare transfer to low income users or to provide for water related common goods type services such as flood control or environmental enhancement.

The researchers review demand theory and present a case study for price/income elasticities of demand for Georgia municipal systems to illustrate price and income effects on revenues. Similar theoretical constructs are presented for two market pricing solutions and for discriminatory pricing within a market for flow type commodities, both systems intended to generate revenue more closely aligned to market value of the services provided. A second case study is used to show how updated alternative cost pricing will lead to increases of 4-10 times in the revenue received from hydropower generation (capacity and energy). Although some repayments are long term contracts, there are opportunities to renegotiate contracts for better terms to Federal agencies producing and marketing hydropower. Specific details are given for the Southeast Power Administration (SEPA).

Principal Investigator: James L. Anderson (The University of Georgia)

Sponsor: GWRI
Start Date: 1986-07-01; Completion Date: 1986-07-01;
Keywords: Water Analysis, Correlation, Electrochemistry, Spectrophotometry

Description:

Theory was developed and experimentally tested for the response of amperometric electrochemical detectors in thin-layer flow channels, and theory was developed and preliminary experiments initiated for the response of spectroelectrochemical correlation detectors in thin-layer flow channels. The theory for amperometric response was evaluated experimentally for several designs of arrays of thin strip microelectrodes in series on one wall of a flow channel, with long axes perpendicular to flow. The electrode arrays were fabricated microlithographically, using gold conductors on silicon dioxide-covered silicon wafers, and platinum conductors on glass or quartz substrates. Experiments were carried out using flow injection methodology with sufficiently large injected volume to insure attainment of steady-state response. Experimental response was in excellent agreement with theoretical prediction, for a series of uniformly spaced arrays of gold microelectrodes with widely varying spacing and number of electrodes. Optimum progression of microelectrode spacing across the array was investigated theoretically. It was shown that the optimum geometry is a uniform array of strip electrodes of equal size and constant spacing. Experimental results support the theoretical conclusion.

Theory was developed for the correlation detector based on electrochemical and spectrophotometric signals generated simultaneously in a thin-layer detector cell. The optimum geometry for the spectrophotometric optical beam was evaluated based on signal/noise considerations, assuming that shot noise was the dominant noise source.

Optimum response is predicted for illumination parallel to the electrode surface and either parallel or perpendicular to flow. Preliminary experiments are qualitatively consistent with theoretical predictions.

Principal Investigator: Dan M. Skolds (Georgia Institute of Technology)
Principal Investigator: Terry W. Sturm (Georgia Tech)

Sponsor: GWRI
Start Date: 1985-06-01; Completion Date: 1986-06-01;
Keywords: Bed load, Dams, Degradation, Rivers, Scour, Sediment

Description:

The effects of man’s activities on an alluvial river are investigated in this research. Specifically, streambed adjustments downstream of a dam constructed on a wide alluvial river are studied experimentally in a laboratory model of an existing alluvial river. The experimental results show that both scour and fill occur in the river bed downstream of the dam as the result of an alluvial bar moving through the system. The bar originates from the local scour hole just downstream of the outlet structure. The channel becomes choked on one side by the bar, while scour occurs on the opposite side of the channel. A numerical model using the streamtube approach is developed to enable prediction of both scour and fill in the same river cross section. The numerical model is tested for sensitivity to the upstream boundary condition, the sediment porosity, the sediment transport relation, and the numerical time step. When compared with the experimental results, the numerical model results agree with the observed scour and fill trends, but the magnitudes are underpredicted. The streamtube approach was found to be a viable technique for investigating two-dimensional streambed adjustments, but additional refinements related to the fundamental problems of transverse velocity distribution and widening due to streambank failure are needed as these problems are illuminated by further research.

Principal Investigator: George A. Brook (University of Georgia)
Principal Investigator: Chin-Hong Sun (The University of Georgia)

Sponsor: GWRI
Start Date: 1985-08-01; Completion Date: 1985-08-01;
Keywords: Modelling, Simulation, Georgia, Hydrology, Lower Coastal Plain, Watershed, Ground Water, Streamflow

Description:
Overland flow to streams is rare in the Lower Coastal Plain watersheds of Georgia. As a result, commonly-used watershed hydrologic simulation models can not be used to predict streamflow accurately. Therefore, a distributed watershed hydrologic simulation model, named COASTAL, has been developed specifically for the Lower Coastal Plain regions of Georgia, Florida, and South Carolina. A basic assumption of the model, which can be run on a personal computer, is that all streamflow results from ground water discharge into stream channels. COASTAL was developed by combining surface and ground water simulation models. In modelling, the watershed is divided into rectangular grid elements. Input data for each grid element can be obtained easily from topographic maps, soil surveys, aerial photographs and generalized published tables. At least one year of measured daily streamflow data is needed to calibrate the model. Outputs from the model include daily stream discharge, a water budget, and average daily ground water level for each grid element within the watershed.

The model has been tested using data for the Hurricane Creek watershed of Georgia. Correlation coefficients between simulated and measured streamflow were in the range 0.8 to 0.9. Work is presently underway to improve COASTAL by installing an automatic calibration module.

Principal Investigator: M. M. Aral (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1984-08-01; Completion Date: 1985-08-01;
Keywords: Ground water seepage, *Finite element method, Multilayer aquifers, Aquifer management

Description:
In order to effectively monitor and manage aquifers subjected to artificial recharge as well as increased pumping demands, it becomes necessary to analyse their hydrodynamic response. Several mathematical/numerical models are developed earlier to accomplish this purpose in a regional scale for single layer aquifers. In the present study a regional two-dimensional flow analysis is formulated using finite element techniques for multilayer aquifers. The advantages of using finite element analysis for aquifer analysis become evident when attempting to model irregular boundaries and variable inputs such as recharge, pumping and field properties in multilayer systems. Numerical solutions are also presented, which when compared with known analytical solutions show the accuracy levels expected and also some limitations of the model. This study is a preliminary step toward the ultimate goal of predicting and monitoring water quality and quantity in a multilayer aquifer system.

Principal Investigator: Gian S. Ghuman (Savannah State College)

Sponsor: GWRI
Start Date: 1984-08-01; Completion Date: 1985-08-01;
Keywords: groundwater, contamination, leaching, sludge, water quality

Description:

A study was conducted on the City of Savannah’s Water Pollution Control Plant to determine the efficiency of wastewater treatment in the removal of heavy metals. Four periodic samples of influent water, effluent water and sewage sludge were collected in October, December, 84 and March, June, 85 and were analyzed for the concentrations of Mn, Zn, Cd, Cu, Ni and Cr. The concentrations of dissolved heavy metals were slightly greater in the treated effluent water than in the influent water. Separation of sludge was effective in the overall removal of heavy metals from the wastewater. The activated sludge component of effluent water had high concentrations of heavy metals and must be fully removed to minimize the heavy metal content in the discharged water. Among the heavy metals, the total concentrations of Zn, Cu and Ni in the effluent water (both the aqueous and the sludge phases) were decreased, which indicated a material balance of zero for these metals when removal in the separated sludge is considered. On the other hand, the total concentrations of Mn, Cd and Cr were increased in the effluent water as compared to the influent water and it may be possibly due to the influent water samples collected from the outlet in the plant not being truly representative of the material, going in for treatment. A leaching study in PVC columns packed with sludge ash (pH 10.4) was conducted using de-ionized water, lagoon water, and acetic acid 5000 ppm (pH 5.0) as the leaching solutions. All leachates contained very low amounts of heavy metals and the incineration of limed sewage sludge into ash appears to be an efficient method of disposal. High concentrations of heavy metals as insoluble oxides in the sludge ash may prove to be a commercial source in the future for chemical separation.

Principal Investigator: James E. Kundell (The University of Georgia)
Principal Investigator: S. Wesley Woolf (The University of Georgia)

Sponsor: GWRI
Start Date: 1984-07-01; Completion Date: 1985-06-01;
Keywords: coastal marshes, drainage, erosion, estuaries, flood control, forest management, Georgia, land use, law, marshes, salt marshes, soils, urban runoff, vegetation, water management, waterfowl, wetlands.

Description:
Georgia is experiencing “Sunbelt” population growth and expansions in agricultural and forestry production resulting in increased pressure to convert wetlands to other uses. An analysis was undertaken of data generated by the Fish & Wildlife Service’s National Wetland Inventory, Georgia Department of Natural Resources’ Landsat land use study, and Soil Conservation Service’s National Resources Inventory. Wetland acreage, distribution, types, and trends were identified for Georgia. A review of case law and statutory law was conducted and wetland management activities of federal, state, and local governments were determined. Alternative management strategies were identified for Georgia.

Principal Investigator: Peter E. Sturrock (Georgia Institute of Technology)

Sponsor: GWRI
Start Date: 1984-08-01; Completion Date: 1985-08-01;
Keywords: Electrochemical Detection, HPLC, Carbamates, Triazines, 2,4-Dinitroaniline Herbicides.

Description:
The research summarized in this report investigated the application of a new electrochemical detector to the high-performance liquid chromatographic analysis of water for three classes of organic pollutants: carbamate pesticides, 2, 4-dinitroaniline herbicides, and triuine pesticides. The detector is a computer-controlled device capable of being programmed to operate in many modes. Rapid-sweep square-wave voltammetry, the preferred mode of operation where applicable, was applied successfully to the triazine pesticides. For these compounds, the detector is more sensitive than a uv detector, and the swept mode of operation is useful in resolving components not separated completely by the chromatographic column. For the 2, 4-dinitroaniline herbicides, the rapid-sweep square-wave voltammetric mode was also successful. However, no clear advantage over the uv detector is evident. For the carbamate pesticides, the swept mode of operation is not suitable because of the slow kinetics for the electron-transfer reactions. However, a DC mode of operation, with extreme potential pulses for electrode cleaning, was very effective. Several of the carbamates detected in this study have not been detected by electrochemical means before. The limits of detection are much superior to those reported for uv detectors or other electrochemical detectors.

Principal Investigator: Adel Shirmohammadi (University of Maryland)
Principal Investigator: Flavio da Silva (The University of Georgia)
Principal Investigator: Daniel L. Thomas (University of Georgia)
Principal Investigator: E. Dale Threadgill (The University of Georgia)

Sponsor: GWRI
Start Date: 1984-09-01; Completion Date: 1985-08-01;
Keywords: Georgia Flatwoods, irrigation, drainage, subirrigation, water table, models, water use, system design, soil hydraulic properties

Description:

This project was conducted on the SEA-MAR farm located in Pierce County, Georgia on Pelham loamy sand soil. The study area included 40 hectares of land under a drainage-subirrigation system of which 38 hectares were in blueberries, 1 hectare in corn and the remaining 1 hectare in soybeans. The system installation included two different drain spacings of 15.3 and 20 m for comparison purposes. Two types of water table management systems were used. They were an open ditch and a closed system network. Seventeen punch-tape water level recorders were used to measure the water level in the soil profile at midfield (on tiles and midway between the tiles), at the open ditch and closed system control structures (one for each), and in an undrained-nonirrigated section of the farm. A punch-tape rainfall recorder was also used to measure rainfall at the site.

Experimental results showed that using inappropriate design criteria or mismanagement can lead to poor performance of the system. Excessive drainage at the early part of the growing season coupled with slow subirrigation phase due to deep drain tiles (tiles were located too deep in less permeable material) resulted in poor performance of the system in the corn field. This led to crop stress. Proper management of the system in the blueberry field resulted in favorable soil water conditions and excellent crop growth.

DRAINMOD, a water management model for shallow water table conditions, was used to simulate the system performance for the conditions of Flatwoods soils. Simulation results indicated that a drain spacing of 18-20 m is appropriate for combined drainage-subirrigation systems for soils similar to those in Pierce County, Georgia. However, more research is required to develop appropriate design guides for other soil types in the Georgia Flatwoods region.

Overall findings showed that a combined drainage-subirrigation system is an appropriate water management scheme to be used in the Flatwoods of south Georgia. A preliminary economic analysis led us to believe that this system, if properly designed, can save up to $144/ha/yr and $129/ha/yr when compared to center pivot/drainage and traveling gun/drainage systems, respectively.

An initial evaluation of the water resources requirement for drainage-subirrigation systems indicated that more water is needed to achieve the same useable application amount than for other systems (center pivot/drainage and traveling gun/drainage). Hopefully, continued research can provide improved management practices and increase the water use efficiency of drainage-subirrigation systems.

Principal Investigator: Joe B. Birch (The University of Georgia)
Principal Investigator: James L. Cooley (University of Georgia)

Sponsor: GWRI
Start Date: 1980-11-01; Completion Date: 1983-05-01;
Keywords: Biomass, flood adapted, floodplain, forest, hydroperiod, moisture limited, oxygen limited, production, subsidy-stress.

Description:
Floodplain forest biomass production followed a bimodal gradient from the wettest to driest sites. The wettest sites were continually flooded and supported a bicultural water tupelo-baldcypress forest that was highly adapted through an extensive water-root system to constant flooding and periodic flushing by riverine floods. The wood production (6379 kg/ha/yr) of this forest was among the highest of the floodplain forests studied. The next wettest site was flooded much of the year, had waterlogged soil for much of the rest of the year, and had a drained soil surface for extended periods. This tupelo-baldcypress, root oxygen limited, forest did not have a water-root system and had the lowest biomass production (3553 kg/ha/yr) of any of the forests studied. The sites that were flooded during some portion of the year but well drained during most of the growing season while maintaining a relatively available soil moisture level were the most productive (6883 kg/ha/yr) floodplain forests. The forest that was only slightly flooded each year by the highest floods had a much lower biomass production (4623 kg/ha/yr) than the heavily flooded and well drained forest. Sites subjected to intermediate levels of flooding and well drained soils had an intermediate level of biomass production (an average of 5240 kg/ha/yr). The upland hardwood, moisture limited forest that is no longer flooded had a low biomass production (3677 kg/ha/yr) similar to that of the waterlogged soil, tupe10-baldcypress forest.