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• Out-of-sample prediction of extreme precipitation using nonstationary models. • Significant trends in data of extreme precipitation are insufficient to warrant the selection of a nonstationary model. • Large prediction uncertainty reduces the support for nonstationary models of extreme precipitation. • (Non)stationary model selection should explicitly account for model complexity. Knowledge of the recurrence intervals of precipitation extremes is vital for infrastructure design, risk assessment, and insurance planning. However, trends and shifts in rainfall patterns globally pose challenges to the application of extreme value analysis (EVA) which relies critically on the assumption of stationarity. In this paper, we explore: (1) the suitability of nonstationary (NS) models in the presence of statistically significant trends, and (2) their potential in modeling out-of-sample data to improve frequency analysis of extreme precipitation. We analyze the benefits of using a nonstationary Generalized Extreme Value (GEV) model for annual extreme precipitation records from Southern Brazil. The location of the GEV distribution is allowed to change with time. The unknown GEV model parameters are estimated using Bayesian techniques coupled with Markov chain Monte Carlo simulation. Next, we use GAME sampling to compute the evidence (and their ratios, the so-called Bayes factors) for stationary and nonstationary models of annual maximum precipitation. Our results show that the presence of a statistically significant trend in annual maximum precipitation alone does not justify the use of a NS model. The location parameter of the GEV distribution must also be well defined, otherwise, stationary models of annual maximum precipitation receive more support by the data. These findings reiterate the importance of accounting for GEV model parameters and predictive uncertainty in frequency analysis and hypothesis testing of annual maximum precipitation data records. Furthermore, a meaningful EVA demands detailed knowledge about the origin and persistence of observed changes. [ABSTRACT FROM AUTHOR]

• Flood resilience approach can drive urban management through better city development. • Residual risk in the decision-making process by flood resilience concept applying. • Assessing interactions between flooding behaviour and urban socioeconomic systems. • Hydrological multi-event scenarios to evaluate flood control measures. • Use of indexes to demonstrate spatially distributed results of flood resilience. Urban flooding is still frequently treated as a direct consequence of excess rainfall, without considering the watershed as an interdependent system connected with the development of its territory. The traditional flood control approach implies in continuous corrective interventions, usually of local character, and resulting from post-events responses. This process requires increasingly large investments to implement (or retrofit) structures capable to accommodate the runoff generated by new urbanized areas. These efforts have not prevented floods from continuing to cause high damages worldwide. Thus, there is a need to change stormwater management strategies, shifting to a risk management approach, not only considering cost-benefit analysis, but also internalizing the residual risk accounting for inherent uncertainties, such as climate change and fast and uncontrolled urban growth. This paper proposes a multi-criteria index, the Urban Flood Resilience index-UFRI, to measure quantitatively urban resilience to floods, supported by a hydrodynamic mathematical model and socio-economic indicators, resulting in spatialized maps as a communicating tool. A case study of an urban watershed in Rio de Janeiro/Brazil is used to demonstrate UFRI potential. [ABSTRACT FROM AUTHOR]

Floods are one of the deadliest natural hazards and are exacerbated by changes in land-use and climate. Urban development decreases infiltration by reducing pervious areas and increases the accumulation of pollutants during dry weather. It also decreases infiltration by reducing pervious areas and increases the accumulation of pollutants during dry periods. During rainy events, there is an increase in pollution concentrations and runoff that may be a source of water supply during drought periods. Modeling the quantity and quality dynamics of stormwater runoff requires a coupled hydrodynamic module capable of estimating the transport and fate of pollutants. In this paper, we evaluate the applicability of a distributed hydrodynamic model coupled with a water quality model (HydroPol2D). First, the model is compared to GSSHA and WCA2D in the V-Tilted catchment, and the limitation of the critical velocity of WCA2D is investigated. We also applied the model in a laboratory wooden board catchment, focusing on the validation of the numerical approach to simulate water quality dynamics. Then, we apply HydroPol2D in the Tijuco Preto catchment, in São Carlos - Brazil, and compare the modeled results with the full momentum solver of the HEC-RAS 2D. This catchment shares similar characteristics with many poorly-gauged and human-impacted catchments worldwide. The implementation of the model, the governing equations, and the estimation of input data are discussed, indicating the challenges and opportunities to scale HydroPol2D into the reality of data scarcity of larger poorly-gauged catchments. For a 1-yr return period of rainfall and antecedent dry days, and assuming an uncertainty of 40% in the water quality parameters, the results indicate that the maximum concentration of total suspended solids (TSS), the maximum load and the mass of the pollutant washed in 30% of the volume are, 456 ± 260 mgL-1km-2, 2. 56 ± 0. 4 kgs-1km-2, and 89 % ± 10 % , respectively. [Display omitted] • A new coupled hydrodynamic and water quality 2D model is developed (HydroPol2D). • The spatial–temporal dynamics of Total Suspended Solids (TSS) is investigated. • We estimate TSS transport rates and first flush for a 1-year return period. • The maximum TSS load is 2. 56 ± 0. 4 kg s − 1 km − 2 for a 40% uncertainty in water quality parameters. • HydroPol2D can also be used for flood inundation mapping, infiltration, and evapotranspiration modeling. [ABSTRACT FROM AUTHOR]

Urban flood management have often focused either on the capacity expansion of drainage systems or on artificial detention storage. While flood control should take part early on urban planning, not enough is known to guide such plans and provide incentive to land use decisions that minimize the vulnerability to localized floods. In this paper, we offer a broader perspective on flood protection, by treating the original hydrologic flow regulation as an environmental service, and exploring how the value of this environmental service drives economic land use decisions that convert original (permeable) land into urbanized (impermeable). We investigate the relationship between land use decisions and their hydrologic consequences explicitly, and use this relationship to simulate resulting land use scenarios depending on the value attached to the environmental service of flow regulation. Rainfall-runoff simulation model results are combined to an optimization model based on two-stage stochastic programming approach to model economic land use decisions. The objective function maximizes the total expected land use benefit in an urban area, considering the opportunity cost of permeable areas in the first stage and the resulting loss of the environmental service of flow regulation on the second stage, under several probable hydrological events. A watershed in the city of Belo Horizonte, Brazil, is used to demonstrate the approach. Different values attached to the environmental service were tested, from zero to higher than the opportunity cost of land, and artificial detention infrastructure was included to calculate the resulting land use change and the loss in the environmental service value. Results indicate that by valuing the environmental service loss and discounting it from the economic benefits of land use, alternative solutions to land use are found, with decreased peak flows and lower flood frequency. Combined solutions including structural and non-structural techniques provide more cost effective results, avoiding both the depletion of the environmental service and the high opportunity cost associated to valuable commercial urban areas. Urban development under such premises will be more resilient and adapted to local flooding, instead of relying on increasingly expensive infrastructure. [ABSTRACT FROM AUTHOR]

• A dye-based modeling approach was made for the first time in a Neoproterozoic karst hydrosystem. • Geo-speleological features association to develop conceptual models of karst systems. • Spatio-temporal resolutions of flow and transport parameters by equilibrium and non-equilibrium models. • Comparison of hydrodynamic behavior of recent karst systems with Neoproterozoic karst. Brazilian Neoproterozoic carbonate rocks, dating from about 740–590 million years ago, contain the oldest karst-structured terrains on Earth, resulting in groundwater flow pathways in highly heterogeneous and anisotropic conduit networks. Unlike Paleozoic and Mesozoic rocks, in Neoproterozoic karst systems, groundwater circulates and stores practically through dissolution features characterized as tertiary porosity, as the rock's primary porosity is recrystallized, considered negligible. However, studies using hydrodispersive equilibrium and non-equilibrium models to estimate flow and transport parameters to base the hydrodynamic behavior of these areas are not common. This paper proposes this, by a set of techniques involving dye tracer tests and the analysis of breakthrough tracer curves (BTCs) in a highly karstified Neoproterozoic terrain. For this, three karst springsheds, in the east, west, and south areas of the São Miguel river watershed, in Alto São Francisco karst region, Brazil, were choose and studied with dye tracer tests using Rhodamine WT and Uranine during dry and wet seasons, associated with regional/local (hydro)geological-structural, geomorphological, and speleological data. The results identified spatial and seasonal variations of water flow and transport parameters, recharge and discharge zones, and water dynamic and speleogenetic evolutions. BTCs models showed the karst systems are very dynamic with seasonal variations, and heterogeneities (bypass, loops and stagnant zones) control the variation of flow and transport parameters. The hydrodispersive parameters (mean flow velocity, and longitudinal dispersion coefficient) and coefficients of non-equilibrium models (partition, β, and mass transfer, ω) show a direct dependence on hydrogeological and speleogenetic contexts. Furthermore, the comparison with other karst systems around the world showed that Neoproterozoic karst has a more stable hydrodynamic behavior under hydrological conditions. [ABSTRACT FROM AUTHOR]

Hydrological models are useful to support ecosystem services restoration. However, when planning the expansion of Nature-based Solutions and Payments for Ecosystem Services, there are requirements including the principle of additionality, representation of multiple runoff mechanisms and calculation of farm-scale spatial outputs and epistemic uncertainty. While addressing these aspects is important to make future planning more effective (investment costs and water benefits) it is also challenging. This paper integrates, in a single modeling framework, the main requirements highlighted. This allows an improved selection of top priority areas with farm-scale spatial resolution and a deeper understanding of how epistemic modeling uncertainty affects the results, which is relevant to evaluate the risks of overestimating ecosystem services benefits. The modeling approach is demonstrated in a case study watershed in the Atlantic Forest biome (Brazil). The PLANS model is introduced, which uses the design of TOPMODEL to simulate both simulates both saturation-excess and infiltration-excess runoff at the farm-scale resolution. Also, it uses a novel saturation index based in a composition of Height Above the Nearest Drainage and Topographical Wetness Index terrain descriptors. We applied the Generalized Likelihood Uncertainty Estimation method, aided by an evolutionary algorithm, to estimate output epistemic uncertainty. Results show that uncertainty substantially affects priority definition (97% ranking change), and that simulated topographic effects can overcome local effects of land cover and soil type. With better data, uncertainty evaluation indicates that the restoration program in the study case could have the cost of its allocation policy reduced by up to 27%, showing that it can be made more cost- effective with the methods proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

• Recovery of hydrological droughts can be 4 times longer than that of meteorological ones. • Recovery time is longest and more severe in dry regions and regions with high water use. • A multi-indicator approach is key to the proper characterization of drought development and propagation. Meteorological droughts propagate through the hydrological cycle causing hydrological droughts and societal impacts. However, the effects of climate and basin characteristics on hydrologic drought propagation vary regionally and remain largely unclear. In this paper, we characterize meteorological and hydrological droughts in 457 basins in Brazil. Using the Standardized Precipitation Evapotranspiration Index (SPEI) and Standardized Streamflow Index (SSI), we investigate hydrologic drought propagation based on differences in drought onset, the center of mass, and time to peak. Additionally, we estimate the recovery time of meteorological and hydrologic drought events. The results indicate that hydrological droughts are usually more long-lasting, severe, and with a slower recovery time compared to meteorological droughts. While the most severe meteorological droughts are observed in humid regions (e.g., Amazon and Southern Brazil), the most severe and long-lasting hydrological droughts are found in the driest region (i.e., Northeast Brazil) or mostly impacted by human activities (i.e., Southeast Brazil). Hydrological droughts in dry regions can take four times longer to recover than meteorological ones. For most regions, the propagation time was slightly different considering the different approaches. Our results highlight the importance of a multi-indicator approach to fully characterize the mechanisms controlling the development and propagation of droughts through the water cycle. [ABSTRACT FROM AUTHOR]

Summary: This paper combines hydrological observations and modelling results of a semi arid catchment in Brazil that could lead to a better understanding of the hydrology of similar catchments in semi-arid regions. The Tapacurá catchment (area 470.5km2) in the Northeast of Brazil was selected for this study. The Distributed Catchment Scale Model, DiCaSM, was calibrated and validated for the stream flows of the Tapacurá catchment. The model performance was further tested by comparing simulated and observed scaled soil moisture. The results showed the ability of the model to simulate the stream flow and the scaled soil moisture. The simulated impacts of climate change of low emission (B1) scenarios, on the worst perspective, indicated the possibility of reduction in surface water availability by −13.90%, −22.63% and −32.91% in groundwater recharge and by −4.98%, −14.28% and −20.58% in surface flows for the time spans 2010–2039, 2040–2069, 2070–2099, respectively. This would cause severe impacts on water supply in the region. Changing the land use, for example by reforestation of part of the catchment area which is currently arable land, would lead to a decrease in both groundwater recharge by −4.2% and stream flow by −2.7%. Changing land use from vegetables to sugar cane would result in decreasing groundwater recharge by almost −11%, and increasing stream flow by almost 5%. The combination of possible impacts of climate change and land use requires a proper plan for water resources management and mitigation strategies. [Copyright &y& Elsevier]

Summary: This paper presents isotopic composition (δ18O, δ2H) of groundwater, lagoon water, and seawater collected in a coastal lagoon system in Southern Brazil as a tool to define groundwater sources within a permeable barrier that separates the lagoon from the ocean. The isotopic signature of the barrier groundwater differs both from the isotopic composition of lagoon water and seawater. The groundwater is significantly lighter, indicating that the major recharge source to the barrier is precipitation, rather than lagoon water. In the southern and central part of the barrier no interaction of groundwater with lagoon water was observed. In the northern part, however, lagoon water intrusion into the barrier was identified. This effect is apparently caused by different vegetation types on the barrier influencing subsurface hydrological processes. The central and the southern areas are characterised by natural dune vegetation (high infiltration, low evapotranspiration rates) whereas the northern part is covered by extensive pine tree plantations (low infiltration, high evapotranspiration rates). The presence of pine trees may enhance lagoon and seawater intrusion into the shallow aquifer and decrease fresh submarine groundwater discharge. [ABSTRACT FROM AUTHOR]

Summary: With the objective of understanding the potential and limitations of available precipitation products for hydrological studies, this paper compares six daily and sub-daily precipitation datasets and their impacts on the water balance of the Negro River basin in the Amazon basin. The precipitation datasets contain gauge-based data [data derived from the Hybam Observatory Precipitation (HOP) dataset and provided by the Climate Prediction Center (CPC)], satellite-based data [the Global Precipitation Climatology Project (GPCP) one-degree daily and TRMM Multisatellite Precipitation Analysis (TMPA) datasets] and model-based data [the NCEP-DOE AMIP-II re-analysis (NCEP-2) and 40-year ECMWF Re-Analysis (ERA-40) datasets]. Each dataset has a common set of meteorological forcing data which are used to run the MGB-IPH hydrological model for the period from January 1998 to August 2002. The average precipitation of all the datasets is 2542mm for the Negro River basin, with a standard deviation of 317mm. TMPA and NCEP-2 have the lowest (2216mm/year) and the highest (3065mm/year) precipitation rates, respectively. The HOP and CPC datasets agree best with observed discharge. GPCP gives the best results among the ungauged datasets, followed by ERA-40. TMPA and NCEP-2 are found to be the least accurate. TMPA can reproduce the water cycles reasonably well, but underestimates the precipitation fields and discharges over the basin, while NCEP-2 is unable to represent the rainfall quantity and cycles, and the water discharge. Results suggest that gauge-based data are still the most representative of the actual precipitation in the northern Amazon basin. However, some satellite and model-based can reproduce fairly well the water cycle at the basin scale and monthly time step. [ABSTRACT FROM AUTHOR]

Summary: The relations between hydrology, geomorphology and vegetation provide the basis for understanding the ecological processes in the floodplains of rivers. In this paper, long-term (1969–2009) local flood characteristics (magnitude, duration, frequency, return period) are quantified for the floodplain of the Cuiabá River (Pantanal wetland in Brazil), using a predictive model based on artificial neural networks (ANNs) with input given by the historic river-level record. Morphological features were then described and their relation to vegetation analyzed and used to reconstruct floods. In addition to the river-level data used to train and validate a three-layer ANN, data were also used from 11 floodplain gauges across a 12km transect lateral to the river, which were monitored during the annual floods of 2004–2007. The resulting neural network gave satisfactory estimates of water depth over the floodplain, with an absolute error of 0.09m not exceeded in 95% of occurrences. The ANN showed that in almost all years, the level reached by the river was high enough to flood the profile completely: the exceptions were 1971 and 2001 when only 50% and 58% was flooded, to mean depths of 0.34 and 0.48m, respectively. The highest flood was that of 1995 when the floodplain was flooded to a mean depth of 2.56m. The median flood event (return period 2years) produced a mean flood depth 1.80m and lasted 119days. Among the most important morphological features is the presence of palaeo-channels which provide hydrological connectivity between the river and the floodplain. The distribution of phytophysiognomic units is significantly influenced by local geomorphology, which determines spatial variation in the magnitude, duration, and frequency of flooding. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a fast and inexpensive method for estimating the bathymetry of hydroelectric reservoirs. Brazil has more than 30 large hydroelectric reservoirs with a combined volume exceeding one billion cubic meters. The hydroelectric sector is responsible for 97% of the energy production in Brazil and is the largest hydroelectric park in the world. Among the variables affecting the environmental impacts of reservoirs, depth plays a major role because it influences the aquatic system hydrodynamics. Reservoir depth distribution (i.e., the bathymetry) is also a fundamental factor controlling the physical–chemical and biological properties of the system. However, the acquisition of bathymetric information for the large reservoirs in Brazil is not a simple task because: (1) most of the topographic maps available in the area of the lake have a very small scale (1:100,000 and smaller), (2) larger charts are the property of the hydropower companies and are classified, and (3) the size of the reservoirs prevent the use of bathymetric surveys. The proposed method of integrating historical and Shuttle Radar Topography Mission (SRTM) topographic data allowed for the estimation of the bathymetry of the Itumbiara reservoir with R 2 =0.98 (n =100, ρ =0.00) and RMSE=3.78m. For researchers who need a rapid and simple method to develop bathymetric maps of hydroelectric reservoirs, the proposed method can provide a simple and fast alternative to more data intensive methods. [Copyright &y& Elsevier]

Summary: Efficient management of water and energy is an important goal of sustainable development for any nation. Streamflow forecasts, have been used in complex optimization models to maximize water use efficiency and electrical energy production. In this paper we develop a statistical model for the long term forecasts of hydroenergy inflow into the Brazilian hydropower system, which consists of more than 70 hydropower reservoirs. At present, the planning of reservoir operation and energy production in Brazil is made with no reliable long term (one season or longer lead times) streamflow forecasts. Here we use the NINO3 index and the main modes of the tropical Pacific thermocline structure as climate predictors in order to achieve skillfull forecasts at long leads. Cross-validated results show that about 50% of the total hydroenergy inflow can be predicted with moderate accuracy up to 20 month lead time. [Copyright &y& Elsevier]

Summary: Rainfall measurements by conventional raingauges provide relatively accurate estimates at a few points of a region. The actual rainfield can be approximated by interpolating the available raingauge data to the remaining of the area of interest. In places with relatively low gauge density such interpolated rainfields will be very rough estimates of the actual events. This is especially true for tropical regions where most rainfall has a convective origin with high spatial variability at the daily level. Estimates of rainfall by remote sensing can be very useful in regions such as the Amazon basin, where raingauge density is very low and rainfall highly variable. This paper evaluates the rainfall estimates of the Tropical Rainfall Measuring Mission (TRMM) satellite over the Tapajós river basin, a major tributary of the Amazon. Three-hour TRMM rainfall estimates were aggregated to daily values and were compared with catch of ground-level precipitation gauges on a daily basis after interpolating both data to a regular grid. Both daily TRMM and raingauge-interpolated rainfields were then used as input to a large-scale hydrological model for the whole basin; the calculated hydrographs were then compared to observations at several streamgauges along the river Tapajos and its main tributaries. Results of the rainfield comparisons showed that satellite estimates can be a practical tool for identifying damaged or aberrant raingauges at a basin-wide scale. Results of the hydrological modeling showed that TRMM-based calculated hydrographs are comparable with those obtained using raingauge data. [Copyright &y& Elsevier]

• Evaporation trends of tropical reservoirs in Brazil were investigated. • Both positive and negative trends in evaporation were observed. • In the industrial region, the negative trend was potentially caused by the impact of pollutant released to the atmosphere. • In the coastal region, the positive trend was related to increasing air temperature. This paper aims to analyze the trends (Mann-Kendall test) of evaporation and climatological variables, including air temperature, relative humidity and wind speed in four reservoirs located in the Brazilian Northeast. The evaporation was estimated through remote sensing using the Surface Energy Balance System for Water (AquaSEBS) model from 1985 to 2018. In addition, it was verified which meteorological parameter has the highest correlation (R2) with the evaporation in order to assess why this process is changing throughout the years in each reservoir. The model performed well, with root mean square error (RMSE) ≤ 1.25 mm/day, percent bias (PBIAS) ≤ 13.70% and coefficient of determination (R2) ≥ 0.51. One reservoir located closer to a coastal zone presented a positive trend (+0.24 mm/34 years), corroborating the measurements of a reference class A pan, and Penman-Monteith equation, while the others, located closer to industrial areas, displayed negative trends (−0.26 to −0.080 mm/34 years). This reduced evaporation was attributed to the impact of industrial pollutant release to the atmosphere, while the increasing effect in the other reservoir was due to its proximity to the coast, which implies an air renewal as the sea breeze contributes for an improvement in the air quality. The meteorological data also presented positive and negative correlations: Temperature exhibited a positive trend (+0.57 °C/34 years), whereas humidity (−4.83%) and wind speed (−0.29 m/s), a negative trend. Evaporation displayed moderate coefficient of determination (R2 > 0.31) with wind speed and humidity. Yet, the reduction of evaporation may be associated with a possible counterbalancing effect of wind speed over humidity. Overall, the results contribute to a better understanding of evaporation trends in a water-scarce region and can be used in a water resources management context as the increasing/reduction of evaporation might significantly impact water availability in this area. [ABSTRACT FROM AUTHOR]

• The roles karst features, urban/industrial growth, and climate in Lake water level depletion. • A new approach for stable isotopic sampling during a pumping test to identify hydraulic connection and GW-lake water mixture. • A 3D-karst conceptual model is presented to explain hydrogeological controls and anthropic effects of the lake depletion. Reduction in volume of surface water bodies can sometimes be associated with hydraulic connections to groundwater aquifers. This is often the case in karstic aquifers that are used for water supply. This paper analyzed possible karst hydrogeological controls and anthropic effects in the depletion of a 1 km2 lake in the municipality of Sete Lagoas, Minas Gerais, Brazil. Several techniques were used for the analyses: long-term pumping test coupled with stable isotopic samplings (18O and 2H) to analyze for hydraulic connections and estimation of groundwater-lake water mixture proportion; geophysical surveys (electrical resistivity image, and vertical electrical sounding) for mapping subsurface discontinuities; potentiometric maps (static and dynamic levels) and urban-industrial expansion of well pumping rates; climatological water budget from 1961 to 2019 for climate variation analyzes; and a 3D-karst hydrogeological modeling. Results show climatic variation combined with urban-industrial expansion increases the demand for water in the region and directly impacts local potentiometric surfaces, and hence the lake water level. Geophysical surveys indicate that lake is karstically structured and identified preferential flowpaths for water infiltration and mixing. The pumping test shows a drawdown stabilization, from a transient-flow regime to a steady-state, indicating a hydraulic connection with a water source that isotopically is more evaporated (common in surface water), which contributes 13% to the mixture. [ABSTRACT FROM AUTHOR]

• Hydroclimatic conditions and water quality affect class A pan coefficients (K) • K-values were correlated with wind speed, air temperature and TP concentration. • Wind-induced phosphorus re-suspension potentially resulted in reduced evaporation. • The impact of K-values on evaporation was negatively related to water availability. The present paper analyses the influence of hydroclimatic forcing and water quality on the evaporation process of Lake Santo Anastácio, a tropical lake with capacity of about 0.4 hm3 and maximum depth of 5 m, located in the city of Fortaleza, Ceará, Brazil. The two-dimensional model CE-QUAL-W2 was used for modelling hydrodynamics and direct evaporation from the lake, and an evaporation estimation equation based on the mass transfer method was calibrated. Subsequently, direct evaporation was modelled while, at the same time, thermal characteristics of the water column were examined. Then, modelled evaporation was compared to measurements obtained over a period of 11 years (2009–2019) with a Class A pan. The results indicated a daily thermal stratification of up to 2 °C. When modelled evaporation was compared with the measurements obtained with the Class A pan, the mean Class A pan coefficients (K) were between 0.66 and 0.69, lower than the values reported in literature, possibly due to the high concentration of pollutants in the lake. Finally, the K coefficients were negatively correlated with wind speed (R2 of 0.51; p -value < 0.05), air temperature (R2 of 0.67; p -value < 0.05) and total phosphorus concentration in the dry period (R2 of 0.41; p -value < 0.05); suggesting that wind-induced phosphorus resuspension attenuated evaporation rates in the lake. These results confirm the direct influence of hydroclimatic conditions and water quality on the evaporation rates of a tropical lake. The impact of different K-values on water availability was also investigated. The results of this study are important to assist in management operations of lakes and reservoirs, mainly in regions which are substantially impacted by evaporation, as is the case of the Brazilian semiarid. [ABSTRACT FROM AUTHOR]