ARIS GEORGAKAKOS | Georgia Institute of Technology (original) (raw)

Papers by ARIS GEORGAKAKOS

relation to the state water planning process. GWRI's River Basin Planning Tool (RBPT) was develop... more relation to the state water planning process. GWRI's River Basin Planning Tool (RBPT) was developed specifically for this purpose and is now being applied to assess water supply availability and gaps in various Georgia basins. The results are communicated to 12 Water Councils that have been formed across the state. GWRI provides training to state engineers and their contractors who are involved in these assessments. The RBPT is further developed as more specific assessment needs arise in the planning process. In addition to the Georgia Tech River Basin Planning Tool, GWRI has completed a comprehensive study on the impacts of climate change for the Apalachicola-Chattahoochee-Flint River Basin shared with Alabama and Florida. The study indicates that droughts will most likely intensify having serious implications on water supply, energy generation, and ecological flows. The study is now being expanded to include all Georgia basins. California: Similar work, collaboratively with the Hydrologic Research Center in San Diego, has focused on climate change impacts on the Northern California water resources system (including the Sacramento and San Joaquin River basins). While the nature of the changes is different, due to hydrologic significance of snow melt, the findings are equally important regarding the need for mitigation and adaptation measures. With funding from

This article presents the potential impacts of climate change on the Apalachicola-Chattahoochee-F... more This article presents the potential impacts of climate change on the Apalachicola-Chattahoochee-Flint (ACF) river basin (Figure 1) in the southeast US. The long term future basin inflow sequences corresponding to A1B and A2 climate change scenarios were used to drive a water resources model that incorporates the river network, all storage projects and hydroelectric facilities, water withdrawals and returns, instream flow requirements, and management procedures. The assessment criteria of impacts include reliability of water supply for municipal, industrial, and agricultural users with current demand level (year 2007) and future projection (year 2050); lake levels; environmental and ecological flow requirements; and hydropower generation. Results indicate that, under the climate change scenarios and with the current management procedures, the system will experience severe adverse water resources impacts such as extended reservoir drawdowns (Figure 2), water supply deficits (Figure 3), and frequent violations of instream flow requirements. Adaptive management procedures and modified operation rules are proposed and tested to mitigate the impacts of climate changes. The results indicate that such measures can significantly reduce adverse climate and demand change impacts (Figure 4 and Figure 5), but they need to be institutionalized as part of state and federal agency policies.

Indications of a climatic change on a global

AGU Fall Meeting Abstracts, Dec 1, 2011

ABSTRACT This report describes the results from the second phase of the Integrated Forecast and R... more ABSTRACT This report describes the results from the second phase of the Integrated Forecast and Reservoir Management (INFORM) demonstration project. The project goal was to use operationally available information to produce reliable ensemble forecasts of reservoir inflow for the major reservoirs of Northern California for lead times from six hours to nine months, and to use these forecasts to generate risk‐based trade‐offs between multiple objectives such as hydroelectric energy generation, water conservation, flood control and fisheries to inform planning and operational decisions. A full‐physics high resolution mesoscale model was implemented for the ensemble prediction of surface precipitation and temperature over the project domain in Northern California with lead times out to 16 days with six‐hourly temporal resolution using initial and boundary conditions from the North American Model and the Global Forecast System operational forecast models at the National Centers of Environmental Prediction of the National Oceanic and Atmospheric Administration. An intermediate complexity regional model with high resolution was implemented to downscale the ensemble forecasts from the Climate Forecast System operational model at the National Centers of Environmental Prediction for lead times out to 41 days. Methodologies for model forecast adjustment to comply with the corresponding observations were formulated and tested. Hydrologic models were aligned with the operational flow prediction models of the California Nevada River Forecast Center. Reservoir and river water temperature and river routing models were developed and integrated into the decision model of INFORM and demonstration information was collected and analyzed. A new decision framework to manage forecast uncertainty was also developed and demonstrated. The project resulted in forecasting precipitation and temperature over the subcatchments of the INFORM domain with high verification skill out to a week in advance. Reservoir inflow forecasts were produced for the shorter lead‐times with good verification skill, while reliable long‐range ensemble reservoir‐inflow forecasts were produced for the decision component of the model that provided useful trade‐off information for management decisions. The benefits from including detailed downstream routing and water temperature modeling were also demonstrated. The project resulted in forecasting precipitation and rainfall over the subcatchments of the Integrated Forecast and Reservoir Management domain out to a week in advance. Reservoir inflow forecasts were produced for the shorter lead‐times, while reliable long‐range ensemble reservoir‐inflow forecasts were produced for the decision component of the model that provided useful trade‐off information. The benefits from including detailed downstream routing and water temperature modeling were also demonstrated.

The contents of this report were developed under a grant from the Department of the Interior, U. ... more The contents of this report were developed under a grant from the Department of the Interior, U. S. Geological Survey. However, those contents do not necessarily represent the policy of that agency, and you should not assume endorsement by the Federal Government. The project period from June to August, 1987, was devoted to the development and testing of a computer code implementing the ELQG control method to the Savannah river system. The model was tested in several control and simulation experiments and demonstrated superior computational efficiency and reliability. The results of this analysis constituted the subject of a technical paper presented at the WATERPOWER '87 ASCE conference in Portland, Oregon (August 17-21). This paper is included in Appendix A and summarizes the work performed.

Climate variability and potential change have important implications for the management of the AC... more Climate variability and potential change have important implications for the management of the ACF and ACT river basins. This article discusses these implications using a decision support system developed by the Georgia Water Resources Institute at Georgia Tech. These assessments are made for historical as well as for potential climates generated by General Circulation Models (GCMs). The most important conclusion is that water resources planning and management decisions, including the water compacts being negotiated, should explicitly recognize and address climate variability and uncertainty by being flexible and adaptive.

Water Resources Research, Apr 1, 1998

Data from the regulated 14,000 km 2 upper Des Moines River basin and a coupled forecast-control m... more Data from the regulated 14,000 km 2 upper Des Moines River basin and a coupled forecast-control model are used to study the sensitivity of flow forecasts and reservoir management to climatic variability over scales ranging from daily to interdecadal. Robust coupled forecast-control methodologies are employed to minimize reservoir system sensitivity to climate variability and change. Large-scale hydrologic-hydraulic prediction models, models for forecast uncertainty, and models for reservoir control are the building blocks of the methodology. The case study concerns the 833.8 x 10 6 m 3 Saylorville reservoir on the upper Des Moines River. The reservoir is operated by the U.S. Corps of Engineers for flood control, low-flow augmentation, and water supply. The total record of 64 years of daily data is divided into three periods, each with distinct characteristics of atmospheric forcing. For each climatic period the coupled forecast-control methodology is simulated with a maximum forecast lead time of 4 months and daily resolution. For comparison, the results of operation using current reservoir control practices were obtained for the historical periods of study. Large differences are found to exist between the probabilistic long-term predictions of the forecast component when using warm or cool and wet or dry initial conditions in the spring and late summer. Using ensemble input corresponding to warm or cool and wet or dry years increases these differences. Current reservoir management practices cannot accommodate historical climate variability. Substantial gain in resilience to climate variability is shown to result when the reservoir is operated by a control scheme which uses reliable forecasts and accounts for their uncertainty. This study shows that such coupled forecast-control decision systems can mitigate adverse effects of climatic forcing on regional water resources. 10 6 m 3 multipurpose reservoir in Iowa, north of Des Moines, which accepts inflows from the 14,000-km 2 upper Des Moines River basin (Figure 1). The system objectives include flood control, water supply, and low-flow augmentation. The ability

AGU Fall Meeting Abstracts, Dec 1, 2014

INTRODUcnON Reservoir operation certainly provides ample opportunity to use computer-aided manage... more INTRODUcnON Reservoir operation certainly provides ample opportunity to use computer-aided management tools. Except for simple systems, namely, small, single objective reservoirs, where optimal decisions are obvious, the decision making process must take into account a plethora of complicating factors. •Uncertain inflows, reservoir and river dynamics, hydroelectric plant characteristics, flood and drought concerns, water supply, energy generation commitments and economics, water quality standards, recreational activities, local and regional water use conflicts and legislation, and public opinion are but a few of the parameters influencing reservoir management decisions. Recent reservoir control research advances combined with fascinating developments in the computer industry provide new opportunities for model use in real time reservoir management. Modern reservoir control methods can now handle dimensionally large systems with both multiple objectives and operational constraints. And, of equal importance, control models can now be implemented on readily accessible microcomputers which encourages potential widespread use and numerous practical applications. Combined with interactive inputoutput graphics interfaces, management models can be designed to maximize user involvement and provide intuitive understanding of the computations in progress. This paper reports on a state-of-the-art reservoir control model for the regulation of the Savannah River System. Except for model features, emphasis is also placed on how model usage can be maximized within the current organizational decision framework. MANAGEMENT PRACllCES The real-time operation of the Savannah Reservoir System requires the close collaboration of several agencies. The operational schedules are first tentatively decided on a weekly basis by the U.S. Army Corps of Engineers District in Savannah. These schedules include hydropower energy

Water Sector Policy Review and Strategy Formulation. Land and Water Bulletin 3. FAO and the World... more Water Sector Policy Review and Strategy Formulation. Land and Water Bulletin 3. FAO and the World Bank, Rome.

AGUSM, May 1, 2007

We describe the principle components of a prototype integrated climate-weather-hydrology forecast... more We describe the principle components of a prototype integrated climate-weather-hydrology forecast and reservoir management system suitable for operational implementation, and the initial demonstration of such a system for improving operational forecasting and water resources management in northern California.

Symposium held on the occasion of the 11th annual Founder's Day celebration, marking the lOOt... more Symposium held on the occasion of the 11th annual Founder's Day celebration, marking the lOOth anniversary of the birth of Ivan Allen, Jr., on March 15, 2011 in the Biltmore Hotel Imperial Ballroom.

The following paragraphs summarize the research activity pursued in relation to the aforementione... more The following paragraphs summarize the research activity pursued in relation to the aforementioned research project: 1. Becoming familiar with the Compaq 386/25 microcomputer and support programs. In particular, experience was gained with the operation of the Ryan McFarland FORTRAN compiler and its differences with the main frame FORTRAN programming language. This activity is part: of our effort to understand the limitations of this microcomputer with respect to memory storage and computer time requirements. These limitations will affect the software design. 2. Evaluation of the HEC-1 streamflow forecasting model. HEC-1 is a physically-based model and, with proper calibration, it can be as good streamflow predictor as any other similar model. Additional reason to select HEC-1 is that the C.O.E. has already had valuable experience with its use in the Savannah system. A weakness is that it is strictly deterministic and cannot provide estimates of the forecast errors. This last deficiency can be corrected if available rainfall-runoff data are available to reliably estimate the forecast error statistics. This along with its efficient use on the Compaq 386/25 microcomputer are currently investigated. 3. Development of reservoir characteristic curves. A part of the control program is a detail description of the reservoir dynamics and functions. These characteristics are reflected on the curves reflecting (a) the elevation versus storage relationship, (b) the tailwater versus outflow relationship, and (c) the turbine power output versus net head and discharge relationship. These curves were developed for each reservoir and turbine using nonlinear regression analysis and data from the Savannah River reservoir regulation manual. The regression statistics indicate satisfactory correspondence between the actual and the computed values.

The work described herein aims to assess the impacts of potential climate change on the Apalachic... more The work described herein aims to assess the impacts of potential climate change on the Apalachicola-Chattahoochee-Flint (ACF) and Alabama-Coosa-Talapoosa (ACT) river basins in the Southeastern US. The assessment addresses the potential impacts on watershed hydrology (soil moisture and streamflow) and on major water uses including water supply, drought management, hydropower, environmental and ecological protection, recreation, and navigation. This investigation develops new methods, establishes and uses an integrated modeling framework, and reaches several important conclusions that bear upon river basin planning and management. Although the specific impacts vary significantly with the choice of the GCM scenario, some general conclusions are that (1) soil moisture and streamflow variability is expected to increase, and (2) flexible and adaptive water sharing agreements, management strategies, and institutional processes are best suited to cope with the uncertainty associated with future climate scenarios.

relation to the state water planning process. GWRI's River Basin Planning Tool (RBPT) was develop... more relation to the state water planning process. GWRI's River Basin Planning Tool (RBPT) was developed specifically for this purpose and is now being applied to assess water supply availability and gaps in various Georgia basins. The results are communicated to 12 Water Councils that have been formed across the state. GWRI provides training to state engineers and their contractors who are involved in these assessments. The RBPT is further developed as more specific assessment needs arise in the planning process. In addition to the Georgia Tech River Basin Planning Tool, GWRI has completed a comprehensive study on the impacts of climate change for the Apalachicola-Chattahoochee-Flint River Basin shared with Alabama and Florida. The study indicates that droughts will most likely intensify having serious implications on water supply, energy generation, and ecological flows. The study is now being expanded to include all Georgia basins. California: Similar work, collaboratively with the Hydrologic Research Center in San Diego, has focused on climate change impacts on the Northern California water resources system (including the Sacramento and San Joaquin River basins). While the nature of the changes is different, due to hydrologic significance of snow melt, the findings are equally important regarding the need for mitigation and adaptation measures. With funding from

This article presents the potential impacts of climate change on the Apalachicola-Chattahoochee-F... more This article presents the potential impacts of climate change on the Apalachicola-Chattahoochee-Flint (ACF) river basin (Figure 1) in the southeast US. The long term future basin inflow sequences corresponding to A1B and A2 climate change scenarios were used to drive a water resources model that incorporates the river network, all storage projects and hydroelectric facilities, water withdrawals and returns, instream flow requirements, and management procedures. The assessment criteria of impacts include reliability of water supply for municipal, industrial, and agricultural users with current demand level (year 2007) and future projection (year 2050); lake levels; environmental and ecological flow requirements; and hydropower generation. Results indicate that, under the climate change scenarios and with the current management procedures, the system will experience severe adverse water resources impacts such as extended reservoir drawdowns (Figure 2), water supply deficits (Figure 3), and frequent violations of instream flow requirements. Adaptive management procedures and modified operation rules are proposed and tested to mitigate the impacts of climate changes. The results indicate that such measures can significantly reduce adverse climate and demand change impacts (Figure 4 and Figure 5), but they need to be institutionalized as part of state and federal agency policies.

Indications of a climatic change on a global

AGU Fall Meeting Abstracts, Dec 1, 2011

ABSTRACT This report describes the results from the second phase of the Integrated Forecast and R... more ABSTRACT This report describes the results from the second phase of the Integrated Forecast and Reservoir Management (INFORM) demonstration project. The project goal was to use operationally available information to produce reliable ensemble forecasts of reservoir inflow for the major reservoirs of Northern California for lead times from six hours to nine months, and to use these forecasts to generate risk‐based trade‐offs between multiple objectives such as hydroelectric energy generation, water conservation, flood control and fisheries to inform planning and operational decisions. A full‐physics high resolution mesoscale model was implemented for the ensemble prediction of surface precipitation and temperature over the project domain in Northern California with lead times out to 16 days with six‐hourly temporal resolution using initial and boundary conditions from the North American Model and the Global Forecast System operational forecast models at the National Centers of Environmental Prediction of the National Oceanic and Atmospheric Administration. An intermediate complexity regional model with high resolution was implemented to downscale the ensemble forecasts from the Climate Forecast System operational model at the National Centers of Environmental Prediction for lead times out to 41 days. Methodologies for model forecast adjustment to comply with the corresponding observations were formulated and tested. Hydrologic models were aligned with the operational flow prediction models of the California Nevada River Forecast Center. Reservoir and river water temperature and river routing models were developed and integrated into the decision model of INFORM and demonstration information was collected and analyzed. A new decision framework to manage forecast uncertainty was also developed and demonstrated. The project resulted in forecasting precipitation and temperature over the subcatchments of the INFORM domain with high verification skill out to a week in advance. Reservoir inflow forecasts were produced for the shorter lead‐times with good verification skill, while reliable long‐range ensemble reservoir‐inflow forecasts were produced for the decision component of the model that provided useful trade‐off information for management decisions. The benefits from including detailed downstream routing and water temperature modeling were also demonstrated. The project resulted in forecasting precipitation and rainfall over the subcatchments of the Integrated Forecast and Reservoir Management domain out to a week in advance. Reservoir inflow forecasts were produced for the shorter lead‐times, while reliable long‐range ensemble reservoir‐inflow forecasts were produced for the decision component of the model that provided useful trade‐off information. The benefits from including detailed downstream routing and water temperature modeling were also demonstrated.

The contents of this report were developed under a grant from the Department of the Interior, U. ... more The contents of this report were developed under a grant from the Department of the Interior, U. S. Geological Survey. However, those contents do not necessarily represent the policy of that agency, and you should not assume endorsement by the Federal Government. The project period from June to August, 1987, was devoted to the development and testing of a computer code implementing the ELQG control method to the Savannah river system. The model was tested in several control and simulation experiments and demonstrated superior computational efficiency and reliability. The results of this analysis constituted the subject of a technical paper presented at the WATERPOWER '87 ASCE conference in Portland, Oregon (August 17-21). This paper is included in Appendix A and summarizes the work performed.

Climate variability and potential change have important implications for the management of the AC... more Climate variability and potential change have important implications for the management of the ACF and ACT river basins. This article discusses these implications using a decision support system developed by the Georgia Water Resources Institute at Georgia Tech. These assessments are made for historical as well as for potential climates generated by General Circulation Models (GCMs). The most important conclusion is that water resources planning and management decisions, including the water compacts being negotiated, should explicitly recognize and address climate variability and uncertainty by being flexible and adaptive.

Water Resources Research, Apr 1, 1998

Data from the regulated 14,000 km 2 upper Des Moines River basin and a coupled forecast-control m... more Data from the regulated 14,000 km 2 upper Des Moines River basin and a coupled forecast-control model are used to study the sensitivity of flow forecasts and reservoir management to climatic variability over scales ranging from daily to interdecadal. Robust coupled forecast-control methodologies are employed to minimize reservoir system sensitivity to climate variability and change. Large-scale hydrologic-hydraulic prediction models, models for forecast uncertainty, and models for reservoir control are the building blocks of the methodology. The case study concerns the 833.8 x 10 6 m 3 Saylorville reservoir on the upper Des Moines River. The reservoir is operated by the U.S. Corps of Engineers for flood control, low-flow augmentation, and water supply. The total record of 64 years of daily data is divided into three periods, each with distinct characteristics of atmospheric forcing. For each climatic period the coupled forecast-control methodology is simulated with a maximum forecast lead time of 4 months and daily resolution. For comparison, the results of operation using current reservoir control practices were obtained for the historical periods of study. Large differences are found to exist between the probabilistic long-term predictions of the forecast component when using warm or cool and wet or dry initial conditions in the spring and late summer. Using ensemble input corresponding to warm or cool and wet or dry years increases these differences. Current reservoir management practices cannot accommodate historical climate variability. Substantial gain in resilience to climate variability is shown to result when the reservoir is operated by a control scheme which uses reliable forecasts and accounts for their uncertainty. This study shows that such coupled forecast-control decision systems can mitigate adverse effects of climatic forcing on regional water resources. 10 6 m 3 multipurpose reservoir in Iowa, north of Des Moines, which accepts inflows from the 14,000-km 2 upper Des Moines River basin (Figure 1). The system objectives include flood control, water supply, and low-flow augmentation. The ability

AGU Fall Meeting Abstracts, Dec 1, 2014

INTRODUcnON Reservoir operation certainly provides ample opportunity to use computer-aided manage... more INTRODUcnON Reservoir operation certainly provides ample opportunity to use computer-aided management tools. Except for simple systems, namely, small, single objective reservoirs, where optimal decisions are obvious, the decision making process must take into account a plethora of complicating factors. •Uncertain inflows, reservoir and river dynamics, hydroelectric plant characteristics, flood and drought concerns, water supply, energy generation commitments and economics, water quality standards, recreational activities, local and regional water use conflicts and legislation, and public opinion are but a few of the parameters influencing reservoir management decisions. Recent reservoir control research advances combined with fascinating developments in the computer industry provide new opportunities for model use in real time reservoir management. Modern reservoir control methods can now handle dimensionally large systems with both multiple objectives and operational constraints. And, of equal importance, control models can now be implemented on readily accessible microcomputers which encourages potential widespread use and numerous practical applications. Combined with interactive inputoutput graphics interfaces, management models can be designed to maximize user involvement and provide intuitive understanding of the computations in progress. This paper reports on a state-of-the-art reservoir control model for the regulation of the Savannah River System. Except for model features, emphasis is also placed on how model usage can be maximized within the current organizational decision framework. MANAGEMENT PRACllCES The real-time operation of the Savannah Reservoir System requires the close collaboration of several agencies. The operational schedules are first tentatively decided on a weekly basis by the U.S. Army Corps of Engineers District in Savannah. These schedules include hydropower energy

Water Sector Policy Review and Strategy Formulation. Land and Water Bulletin 3. FAO and the World... more Water Sector Policy Review and Strategy Formulation. Land and Water Bulletin 3. FAO and the World Bank, Rome.

AGUSM, May 1, 2007

We describe the principle components of a prototype integrated climate-weather-hydrology forecast... more We describe the principle components of a prototype integrated climate-weather-hydrology forecast and reservoir management system suitable for operational implementation, and the initial demonstration of such a system for improving operational forecasting and water resources management in northern California.

Symposium held on the occasion of the 11th annual Founder's Day celebration, marking the lOOt... more Symposium held on the occasion of the 11th annual Founder's Day celebration, marking the lOOth anniversary of the birth of Ivan Allen, Jr., on March 15, 2011 in the Biltmore Hotel Imperial Ballroom.

The following paragraphs summarize the research activity pursued in relation to the aforementione... more The following paragraphs summarize the research activity pursued in relation to the aforementioned research project: 1. Becoming familiar with the Compaq 386/25 microcomputer and support programs. In particular, experience was gained with the operation of the Ryan McFarland FORTRAN compiler and its differences with the main frame FORTRAN programming language. This activity is part: of our effort to understand the limitations of this microcomputer with respect to memory storage and computer time requirements. These limitations will affect the software design. 2. Evaluation of the HEC-1 streamflow forecasting model. HEC-1 is a physically-based model and, with proper calibration, it can be as good streamflow predictor as any other similar model. Additional reason to select HEC-1 is that the C.O.E. has already had valuable experience with its use in the Savannah system. A weakness is that it is strictly deterministic and cannot provide estimates of the forecast errors. This last deficiency can be corrected if available rainfall-runoff data are available to reliably estimate the forecast error statistics. This along with its efficient use on the Compaq 386/25 microcomputer are currently investigated. 3. Development of reservoir characteristic curves. A part of the control program is a detail description of the reservoir dynamics and functions. These characteristics are reflected on the curves reflecting (a) the elevation versus storage relationship, (b) the tailwater versus outflow relationship, and (c) the turbine power output versus net head and discharge relationship. These curves were developed for each reservoir and turbine using nonlinear regression analysis and data from the Savannah River reservoir regulation manual. The regression statistics indicate satisfactory correspondence between the actual and the computed values.

The work described herein aims to assess the impacts of potential climate change on the Apalachic... more The work described herein aims to assess the impacts of potential climate change on the Apalachicola-Chattahoochee-Flint (ACF) and Alabama-Coosa-Talapoosa (ACT) river basins in the Southeastern US. The assessment addresses the potential impacts on watershed hydrology (soil moisture and streamflow) and on major water uses including water supply, drought management, hydropower, environmental and ecological protection, recreation, and navigation. This investigation develops new methods, establishes and uses an integrated modeling framework, and reaches several important conclusions that bear upon river basin planning and management. Although the specific impacts vary significantly with the choice of the GCM scenario, some general conclusions are that (1) soil moisture and streamflow variability is expected to increase, and (2) flexible and adaptive water sharing agreements, management strategies, and institutional processes are best suited to cope with the uncertainty associated with future climate scenarios.