Ramesh Teegavarapu

Ramesh Teegavarapu
Florida Atlantic University | FAU · Department of Civil, Environmental and Geomatics Engineering

Ph.D. P.E.

About

145
Publications
11,108
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Introduction
Dr. Ramesh Teegavarapu (Dr. T.) is currently a professor and graduate program Director & coordinator in the Department of Civil, Environmental and Geomatics department at Florida Atlantic University (FAU), Boca Raton, Florida and founder and leader of the Hydrosystems Research Laboratory (HRL) in the department. Lab: hrl.fau.edu Dr. T.’s major research focus area is Precipitation Analysis and Estimation http://faculty.eng.fau.edu/ramesh/precipitation-research/

Publications

Publications (145)
Article
Full-text available
Understanding the impact of climate change and human activities on the hydrological cycle of any watershed can provide a scientific basis for regional water resource planning, flood management, and disaster mitigation. An improved three-parameter hydrological model (CM) based on monthly water balance using an exponential equation to depict the dist...
Article
Scale-dependent and -independent error and performance measures are used to evaluate hydrologic forecasting and simulation models. However, these single-valued measures may not always provide a comprehensive assessment of model performance developed for a specific hydrologic process and application. A new frequency-based performance measure (FBPM)...
Chapter
Mean areal precipitation (MAP) estimate continues to serve as one of the essential inputs to lumped hydrologic simulation models. Accurate MAP estimates require error and gap-free precipitation measurements from rain gauge monitoring networks and bias-corrected weather radar and satellite-based quantitative precipitation estimates (QPEs). MAP estim...
Article
Joint variations of precipitation (P) and temperature (T) under the influence of climate variability are examined in this study. Individual and joint influences of Atlantic multidecadal oscillation (AMO) and El Niño southern oscillation (ENSO) on P and T variability in a tropical region (i.e., Florida) are investigated. A rank-based association mea...
Article
Full-text available
Accurate long-term streamflow forecast is essential to alleviate and solve the water security problems related to flood and drought disaster warnings. In this study, a new strategy by forecasting monthly streamflow is proposed and four different scenarios are designed for the evaluation of different roles of baseflow and surface runoff on performan...
Article
Understanding the influences of local hydroclimatology and two large‐scale oceanic‐atmospheric oscillations (i.e., Atlantic Multidecadal Oscillation (AMO) and El Niño‐Southern Oscillation (ENSO)) on seasonal precipitation (P) and temperature (T) relationships for a tropical region (i.e., Florida) is the focus of this study. The warm and cool phases...
Article
Full-text available
Baseflows are one of the important components of streamflows and the influences of climate change and variability on changes in baseflows in space and time can aid in the management of low flows in watersheds. This study focuses on influences of climate variability on baseflows manifested through individual and coupled oceanic-atmospheric oscillati...
Article
Assessment of stationarity in any hydroclimatic time series is a vital task for hydrologic design and climate change assessments. Methods that rely on the presence of statistically significant trends or change points to derive inferences about stationarity may fail to check for all the time-invariant characteristics of time series. An approach that...
Article
Full-text available
Flood risk analysis is the instrument by which floodplain and stormwater utility managers create strategic adaptation plans to reduce the likelihood of flood damages in their communities, but there is a need to develop a screening tool to analyze watersheds and identify areas that should be targeted and prioritized for mitigation measures. The auth...
Article
Full-text available
Trends in baseflows based on observed daily streamflow data are evaluated in this study at several sites in the least anthropogenically affected watersheds in the USA. Trends were determined for annual maximum, annual mean, and annual median baseflow. Baseflow values derived at 574 stations in the USA for the 44 years from 1970 through 2013 are ana...
Article
Predicting and mapping high water table elevation in coastal landscapes is critical for both science application projects like inundation risk analysis and engineering projects like pond design and maintenance. Previous studies of water table mapping focused on the application of geostatistical methods, which cannot predict values beyond an observa...
Article
Full-text available
The aim of this research is the detection and analysis of existing trends in the Meta River, Colombia, based on the streamflow records from seven gauging stations in its main course, for the period between June 1983 to July 2019. The Meta River is one of the principal branches of the Orinoco River, and it has a high environmental and economic value...
Conference Paper
El Niño southern oscillation (ENSO) events throughout the world are known to influence regional (or local) hydroclimatic variability and changes in essential climatic variables (i.e., temperature, precipitation, and others). Variations in temperature extremes influenced by ENSO may lead to spatial and temporal variability of energy consumption and...
Article
Full-text available
A comprehensive assessment and bias corrections of two gridded daily precipitation products, based on gauge-only and multi-satellite observations, are undertaken in this study using independent rain gauge data in and around the Kabini River (KR) basin in South India. The KR basin, with complex terrain, highly variable precipitation and heterogeneou...
Article
Full-text available
Baseflow estimation and evaluation are two critical and essential tasks for water quality and quantity, drought management, water supply, and groundwater protection. Observed baseflows are rarely available and are limited to focused pilot studies. In this study, an exhaustive evaluation of four different baseflow separation methods (HYSEP, WHAT, BF...
Article
Full-text available
A Mixed-Integer Nonlinear Programming (MINLP) model is formulated and solved in this study to optimize environmental sustainability of flood control, drainage, and irrigation (FCDI) projects in the deltaic regions of Bangladesh. The model optimizes the value of integrated resource benefit, a dimensionless variable defined to measure the environment...
Article
Euclidean distance-based spatial interpolation methods that are conceptually simple are commonly used for the imputation of missing precipitation and other hydroclimatic variable datasets. Improved variants of these methods are essential as Euclidean distance will not always serve as an appropriate surrogate that can quantify the inter-gauge relati...
Chapter
Since the introduction of environmental legislation and directives in Europe, the impact of combined sewer overflows (CSO) on receiving water bodies has become a priority concern in water and wastewater treatment industry. Time-consuming and expensive local sampling and monitoring campaigns have been carried out to estimate the characteristic flow...
Conference Paper
Full-text available
Historically, water quality analysis and water management planning have been dependent on accurate assessment of baseflows. Understanding the relationship between oceanic-atmospheric variability and baseflow changes in the continental United States that is beneficial for water resources management is the focus of this study. Baseflows obtained from...
Article
This study proposes an integrated approach by combining a pattern recognition technique and a process simulation model, to assess the impact of various climatic conditions on influent characteristics of the largest Italian wastewater treatment plant (WWTP) at Castiglione Torinese. Eight years (viz. 2009–2016) of historical influent data namely infl...
Article
The accuracy of gridded precipitation data depends on the availability of a uniformly spaced rain gauge network and an appropriate spatial interpolation method that considers the rainfall variability and other factors that influence the precipitation patterns in the region of interest. In the current study, conceptually superior variants of a widel...
Article
Full-text available
Since the introduction of environmental legislations and directives, the impact of combined sewer overflows (CSO) on receiving water bodies has become a priority concern in water and wastewater treatment industry. Time-consuming and expensive local sampling and monitoring campaigns are usually carried out to estimate the characteristic flow and pol...
Article
Full-text available
Runoff generation process in any watershed is mainly affected by precipitation, land use and land cover, existing soil moisture conditions and losses. Shallow groundwater table conditions that occur in many regions are known to affect the soil moisture retention capacity, infiltration and ultimately the runoff. A methodology that links soil moistur...
Article
Streamflow time series often provide valuable insights into the underlying physical processes that govern responses of any watershed to storm events. Patterns derived from time series based on repeated structures within these series can be beneficial for developing new or improved data-driven forecasting models. Data-driven models, artificial neura...
Article
Full-text available
Two screening methods aimed at selection of predictor variables for use in a statistical downscaling (SD) model developed for precipitation are proposed and evaluated in this study. The SD model developed in this study relies heavily on appropriate predictors chosen and accurate relationships between site-specific predictand (i.e. precipitation) an...
Article
Design storms are used for the sizing of urban drainage systems and for delineating floodplains. Recorded rainfall extremes are commonly used to develop design storms with the assumption of stationarity. However, the projections provided by climate models indicate a continued increase in the magnitude and frequency of rainfall extremes. Therefore,...
Chapter
Sustainable water resource planning for climate change is a process of assessing risks related to climate change, evaluating and selecting strategies that are based on current hydrological knowledge, using climate models, monitoring existing conditions, and providing guidelines for adaptation and the optimal use of available water resources for the...
Chapter
Climate variability and change are expected to bring several changes to hydrologic cycles and regimes in different parts of the world. Natural climate variability based on large-scale, global inter-year, quasi-decadal and decadal, and multidecadal-coupled oceanic–atmospheric oscillations (e.g., El Niño Southern Oscillation (ENSO), Atlantic Multidec...
Article
Variants of spatial interpolation and data-driven methods to fill gaps in daily precipitation records are developed and evaluated in this study. The evaluated methods include variations of inverse distance and correlation weighting procedures, linear weight optimization and artificial neural networks. An already existing method, support vector logi...
Article
This study focuses on the assessment of biases from infilling missing precipitation data on the detection of long-term change using parametric and non-parametric statistical techniques. Long-term historical precipitation data available for almost 100 years at 53 rain gages in south Florida, USA, with gages having varying lengths of missing data are...
Book
This book discusses different aspects of water resources, ranging from hydrology and modeling to management and policy responses. Climate changes and the uncertainty of future hydrological regimes make sustainable water resources management a difficult task, requiring a set of approaches that address climate variability and change. The book focuses...
Article
Full-text available
SUMMARY OF RECOMMENDATIONS FOR POLICYMAKERS ON ADAPTION TO CLIMATE CHANGE IN WATER ENGINEERING
Article
Assessment of radar-based precipitation estimates using rain gauge observations is a critical exercise in evaluating pre-and postcorrected (gauge-adjusted) radar-based precipitation data. A comprehensive assessment framework combining several visual, quantitative, and statistical measures, indexes, and skill scores is proposed and developed for eva...
Article
Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.
Article
A methodology for optimal ground-based sensor network design for an evapotranspiration (ET) estimation method which uses solar radiation as the only parameter is developed and evaluated in this study. The methodology employs geospatial analyses and a geostatistical approach, and data from ground-based sensors and satellite-based estimates of solar...
Article
Full-text available
Several statistical downscaling models have been developed in the past couple of decades to assess the hydrologic impacts of climate change by projecting the station-scale hydrological variables from large-scale atmospheric variables simulated by general circulation models (GCMs). This paper presents and compares different statistical downscaling m...
Article
New optimal proximity-based imputation, K-nearest neighbour (K-NN) classification and K-means clustering methods are proposed and developed for estimation of missing daily precipitation records. Mathematical programming formulations are developed to optimize the weighting, classification and clustering schemes used in these methods. Ten different b...
Conference Paper
Following September 11, 2001, numerous security policies were created which have caused a number of unique challenges in planning for the transportation networks. In particular, there is a need to enhance security by improving collaboration between various transportation modes. Improved intermodal connectivity has, therefore, been identified as one...
Article
Understanding the influences of Atlantic multidecadal oscillation (AMO) and El Niño southern oscillation (ENSO) on regional precipitation extremes and characteristics in state of Florida is the focus of this study. Exhaustive evaluations of individual and combined influences of these oscillations using, descriptive indices-based assessment of stati...
Article
Spatial interpolation methods used for estimation of missing precipitation data generally under and overestimate the high and low extremes, respectively. This is a major limitation that plagues all spatial interpolation methods as observations from different sites are used in local or global variants of these methods for estimation of missing data....
Article
A simulation model is developed to understand the dynamic behavior of a hydraulically coupled multiple reservoir system when operated in real-time. An object-oriented simulation environment conceived on the principles of system dynamics (SD) is used for the development of the model. The modeling process consists of developing causal loop, stock and...
Article
Stormwater system management in urban watersheds is often achieved by effective design and use of detention ponds which help mitigate impacts of urban drainage from water quantity and quality perspectives. The costs associated with these tasks for management can be minimized considering the fulfillment of objectives of environmental and regulatory...
Article
[1] Precipitation as an important component of hydrologic cycle bears a significant influence on hydrologic design and water resources management. The uncertainties associated with future climate change coupled with limitations of climate change models and uncertainties in projections, our inability to quantify these introduce additional complexiti...
Article
[1] Optimal operation models for a hydropower system using new fuzzy multiobjective mathematical programming models are developed and evaluated in this study. The models use (i) mixed integer nonlinear programming (MINLP) with binary variables and (ii) integrate a new turbine unit commitment formulation along with water quality constraints used for...
Conference Paper
Several statistical downscaling models have been developed in the past couple of decades to assess the hydrologic impacts of climate change by projecting the station-scale hydrological variables from large-scale atmospheric variables simulated by general circulation models (GCMs). GCMs have a good chance to capture the large-scale circulation patte...
Conference Paper
Internal modes of climate variability defined as teleconnections have known to have an effect on precipitation extremes relating to magnitude and frequency. Evaluation of influences of climate variability on storm event characteristics, especially the interevent time definition (IETD) defined by minimum dry period between storm events is the main f...
Conference Paper
Statistical downscaling modeling-based results often depict biases and are incapable of reproducing the variances and approximating the distributions of the predictands. This paper proposes a multi-objective optimization framework to reduce biases resulting from the limitations of the transfer function methods adopted under statistical downscaling...
Conference Paper
Deterministic and stochastic weighting methods are the most frequently used methods for estimating missing rainfall values at a gauge based on values recorded at all other available recording gauges. However, spatial interpolation methods used for estimation of missing precipitation data at a site seldom check for their ability to preserve site and...
Conference Paper
Given the climate variability and change throughout the world, local level continuous assessment of storm event characteristics is critical for analyzing adequacy of existing urban drainage infrastructures and for updating the critical rainfall information for future hydrologic designs. Given such new information, it is instructive to analyze this...
Article
Optimal operation models for a hydropower system using partial constraint satisfaction (PCS) approaches are proposed and developed in this study. The models use mixed integer nonlinear programming (MINLP) formulations with binary variables. The models also integrate a turbine unit commitment formulation along with water quality constraints used for...
Conference Paper
New optimal proximity-based imputation, k-nn (k-nearest neighbor) classification and k-means clustering methods are proposed and developed for estimation of missing precipitation records in this study. Variants of these methods are embedded in optimization formulations to optimize the weighing schemes involving proximity measures. Ten different bin...
Conference Paper
Watershed run-off models were mostly developed using point rainfall observations in the past. For several decisions making, water quality model using watershed run-off models. The water quality modeling can be done in a better manner if radar rainfall data is used in the modeling process. However, radar rainfall is not directly available for this p...
Conference Paper
Deterministic and stochastic weighting methods are the most frequently used methods for estimating missing rainfall values at a gauge based on values recorded at all other available recording gauges. However, spatial interpolation methods used for estimation of missing precipitation data at a site seldom check for their ability to preserve site and...
Conference Paper
Bias corrections of radar data using ground truth is essential and critical step in generation of viable precipitation data sets. The improvement in the radar data achieved through the correction procedures depend on several factors including available rain gage data, gage density and reliability of ground truth. Availability of rain gage data at t...
Conference Paper
Precipitation being a vital input for many hydrological modeling studies has a direct bearing on the water resources modeling and management at different spatial and temporal scales. According to Intergovernmental Panel on Climate Change (IPCC), frequency of extreme precipitation events is expected to increase in future with no consistent trend in...
Conference Paper
Two major teleconnections, AMO (Atlantic multi-decadal oscillation) and ENSO (El Niño southern oscillation) under cool and warm cycles (phases) influencing precipitation patterns in Florida are assessed in this study. Temporal shift in the occurrences of precipitation extremes and changes in the magnitudes of these extremes are evaluated in differe...
Article
New mathematical programming models are proposed, developed and evaluated in this study for estimating missing precipitation data. These models use nonlinear and mixed integer nonlinear mathematical programming (MINLP) formulations with binary variables. They overcome the limitations associated with spatial interpolation methods relevant to the arb...
Article
Geo-spatial interpolation methods are often necessary in instances where the precipitation estimates available from multisensor source data on a specific spatial grid need to be transformed to another grid with a different spatial grid or orientation. The study involves development and evaluation of spatial interpolation or weighting methods for tr...
Article
Management of water resources has become more complex in recent years as a result of changing attitudes towards sustainability and the attribution of greater attention to environmental issues, especially under a scenario of water scarcity risk introduced by climate changes and anthropogenic pressures. This study addresses the optimal short-term ope...
Article
Use of appropriate functional reflectivity (Z)-rainfall rate (R) relationships is crucial for accurate estimation of precipitation amounts using radar. The spatial and temporal variability of several storm patterns combined with subjectivity in application of a specific functional Z-R relationship for a particular storm makes this task very difficu...
Article
Assessment of spatial and temporal extreme precipitation events due to climate variability and change is critical for future hydrologic design. Evaluation of these extremes in the past has been limited to evaluation of annual and partial duration series. However, climate-change sensitive hydrologic design requires evaluation of precipitation extrem...
Article
Two major teleconnections, AMO (Atlantic multi-decadal oscillation) and ENSO (El Niño southern oscillation) under cool and warm cycles (phases) influencing precipitation patterns in Florida are assessed in this study. Temporal shift in the occurrences of precipitation extremes and changes in the magnitudes of these extremes are evaluated in differe...
Article
Spatial interpolation methods used for estimation of missing precipitation data at a site seldom check for their ability to preserve site and regional statistics. Such statistics are primarily defined by spatial correlations and other site-to-site statistics in a region. Preservation of site and regional statistics represents a means of assessing t...
Article
The timing and spatial distribution of extreme precipitation and peak discharge events along with the conveyance capacity of the hydraulic structures in a basin determine the extent of flooding. Assessment of spatial and temporal distribution of extreme precipitation and stream discharges and consequent evaluation of streamflow response considering...
Article
Assessment of long-term trends in extreme precipitation data is critical for hydrologic design. Understanding of such trends is also essential from a climate change perspective and requires an extensive evaluation of trends in different temporal slices of historical precipitation data series. The current study focuses on evaluation of these trends...
Conference Paper
Total maximum daily loads (TMDLs) for different water quality constituents were developed for many creeks, which are listed by United States Environmental Protection Agency (USEPA) 303(d) document. When available data for estimation of loads are uncertain, the TMDL decisions are also affected. To provide flexibilities for the decision maker, in thi...
Article
The impact of climate change on hydrologic design and management of hydrosystems could be one of the important challenges faced by future practicing hydrologists and water resources managers. Many water resources managers currently rely on the historical hydrological data and adaptive real-time operations without consideration of the impact of clim...
Conference Paper
In the current study the use of optimal spatial interpolation and data driven models for infilling of rain gage data using NEXRAD based precipitation estimates is investigated. A total of 12 optimization model formulations were proposed, developed and were implemented in this study. The optimization models were developed using nonlinear and mixed i...
Conference Paper
Uncertainty assessment of hydrologic model inputs and outputs is generally achieved by using Monte Carlo perturbation schemes adopted for specific input parameters. Several variants of perturbation schemes ranging from simple random sampling to Latin-hypercube sampling schemes are used in hydrologic modeling for uncertainty estimation purposes. Thi...
Conference Paper
Inter-event Time Definition (i.e., minimum dry period between storm events, or IETD) is a very crucial parameter that is often neglected in the analysis of rainfall time series. Based on an IETD, a long-term rainfall record can be analyzed for different storm event characteristics such as rainfall event volume, duration, intensity and inter-event t...
Article
Use of appropriate reflectivity (Z)-rain rate(R) relationships is crucial for accurate estimation of precipitation amounts using radar. The spatial and temporal variability of several storm patterns combined with availability of several variants of Z-R relationships makes this task very difficult. This study evaluates the use of optimization models...