Downstream Temperature Research Articles

Numerical investigation of upward supercritical water flow with Joule heating effect

By using Joule's Law, resistivity equation, Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) functions, and resistivity-temperature correlation established based on the available experimental data, Joule heating heat flux profiles of upward supercritical water heat transfer in the annular tube are modelled and applied as the boundary condition. The calculated wall temperature result is compared to the Razumovskiy et al. experiment dataset. It is discovered that by using the PCHIP-modelled Joule heating profiles, the estimated wall temperature for both the Normal Heat Transfer (NHT) and Deteriorated Heat Transfer (DHT) regimes is comparable to the experiment in terms of trend and magnitude. However, by using the conventional constant heat flux profiles, the upstream and downstream wall temperatures are overestimated and underestimated respectively. This study demonstrated that CFD can adequately replicate experimental heat flux conditions, hence improving CFD estimates of supercritical heat transfer, particularly for the DHT, which has a substantial heat flux variation. With this fine imitation of the Joule heating heat flux, the critical DHT regime can be more accurately predicted.

Experimental Study on the Smoke Temperature Decrease near Natural Vents Induced by Air Entrainment in a Tunnel Fire

Previous studies have shown that there is a large difference in the temperature of smoke in the upstream and downstream of a vertical shaft, but no quantitative study on the subject has been conducted. In this paper, a model experimental test was conducted to study the effect of a natural vertical shaft on the distribution of smoke temperature in tunnel fires. A laser sheet was used as an assisting tool to show the smoke flow field. A series of tests were conducted with shaft heights varying from 0.2 m to 1.2 m and a heat release rate (HRR) of 9 kW, 17 kW, 29 kW, and 65 kW. The entrainment phenomenon around the vertical shaft was analyzed, and the results showed that the amount of fresh air entrainment is the main reason for the temperature decrease in upstream and downstream smoke temperatures. Based on the experimental results, an empirical model for predicting the amount of fresh air entrainment and a prediction model of the downstream smoke temperature were proposed, and the predicted values are in good agreement with the experimental values.

Role of the overshoot in the shock self-organization

A collisionless shock is a self-organized structure where fields and particle distributions are mutually adjusted to ensure a stable mass, momentum and energy transfer from the upstream to the downstream region. This adjustment may involve rippling, reformation or whatever else is needed to maintain the shock. The fields inside the shock front are produced due to the motion of charged particles, which is in turn governed by the fields. The overshoot arises due to the deceleration of the ion flow by the increasing magnetic field, so that the drop of the dynamic pressure should be compensated by the increase of the magnetic pressure. The role of the overshoot is to regulate ion reflection, thus properly adjusting the downstream ion temperature and kinetic pressure and also speeding up the collisionless relaxation and reducing the anisotropy of the eventually gyrotropized distributions.

Effect of edge ion temperature on the divertor tungsten sputtering in WEST

The influence of upstream ion temperature in the scrape-off layer (SOL) on the tungsten (W) sputtering in the divertor is studied in the WEST tokamak. For an almost constant power into the SOL, the upstream ion temperature and its ratio over the electron temperature gradually increase with the decrease of electron density in the SOL. This increment is observed to enhance the energy transfer from ions to electrons. This increases the downstream electron temperature and by coupling of electrons and ions, the impact energy of ions causing W sputtering in the divertor. This enhancement mechanism may become crucial to sputtering the W material for high upstream T i/T e ratio since the impact energy of ions in the divertor would increase accordingly.

Elucidation of exhaust gas recirculation deposit formation mechanism based on chemical analysis of components

To comply with strict emission regulations, vehicles are equipped with exhaust gas recirculation (EGR) systems that control nitrogen oxide emissions by returning part of the exhaust gas to the intake air. However, since deposits form in the EGR piping and valves, leading to pipe clogging, valve sticking, and in the worst case, failure of these components, there is a need to clarify the mechanism of deposit formation to predict and reduce deposit accumulation. While most of the previous studies have focused on the powdery deposits that clog the EGR cooler, this study aims to elucidate the formation mechanism of both the lacquer-like hard deposits and wet soft deposits that cause EGR valve sticking by quantitative and molecular-level analyses. In these experiments, a portion of the exhaust gas from an actual diesel engine without soot removed by diesel particulate filter (DPF) was used. Deposits were continuously generated on a simulated EGR line with a downstream temperature gradient from the engine outlet, while measuring the inner wall temperature. The collected deposits were subjected to comprehensive chemical analysis. The analysis showed that 75 % of the solvent-soluble deposit components were polycyclic aromatic hydrocarbons (PAHs), which were the main component of the hard and soft deposits. Most of the PAHs in the hard deposits that formed at a high inner wall temperature were C17 or higher. The hard deposit with an inner wall temperature of 137 °C contained 0.016 mg/cm2 of 6-ring benzo[ghi]perylene and 0.26 × 10-3 mg/cm2 of 4-ring pyrene. On the other hand, the soft deposit is formed at an inner wall temperature of 80 °C, contained 0.022 mg/cm2 of pyrene, which is significantly more than in the hard deposit. This shows that PAHs in the exhaust gas condense when the gas temperature reaches their dew points, and that the deposits formed at higher inner wall temperatures contain more PAHs with higher boiling points. High-molecular weight aromatic compounds with oxygen and nitrogen functional groups were detected in the solvent-insoluble deposit components. These compounds were found to be derived from the polymerization of oxygenated and nitrogenated PAHs through dehydration condensation and cross-linking reactions.

Numerical study on fire behavior and temperature distribution in a blind roadway with different sealing situations.

Blind roadways have only one portal which connects with other types of mine roadways. Sealing the fire area in a blind roadway is an effective method of disaster relief in a mine. To understand the effect of sealing ratio and sealing distance on fire behavior, Fire Dynamics Simulator (FDS 6.6) was used to study blind roadway fires with different fire scenarios. Results indicate that the smoke flow velocity increases significantly with the increase of sealing distance. The fire in the blind roadway is ventilation-controlled. When the sealing ratio reaches 80%, the fire self-extinguishes completely. Otherwise, the fire experiences an extinguishing-reburning cycle periodically. Besides, an empirical model is proposed to predict the downstream temperature distribution beneath the ceiling in the region from fire source to sealing position. The predictions by the proposed model comply well with the simulation and experimental results from our and others' studies. This study provides new insights into the sealing strategies in blind roadway fires, and the outcomes of the current study are of guiding significance for the fire rescue in the blind roadways or similar structures.

Ceiling temperature distribution and decay in tunnel fires: Effect of longitudinal velocity, bifurcated shaft exhaust and fire location

This paper establishes a model tunnel to investigate the impact of longitudinal velocity (u), bifurcated shaft exhaust velocity (BSEV) and fire location on ceiling temperature and decay. The experimental results show that a longitudinal velocity of 0.6 m/s can control the upstream high temperature within 2.5 m when the distance between fire and shaft (D) is 1.0 m, and further increase in longitudinal velocity has little effect on upstream temperature distribution. Downstream temperature profile should be divided into two cases according to the magnitude of longitudinal velocity: the difference between the temperature decay model in low-speed region (u ≤ 0.5 m/s) and that in the high-speed region (u > 0.5 m/s) is particularly obvious with D at 1.0 m, and the downstream temperature decay rate in the low-speed region is the slowest compared to all the working conditions in this paper. For D more than 1.0 m, the range of high temperature distribution increases with D for certain longitudinal velocities (0.6-0.7 m/s); however, at particularly large longitudinal velocity (0.8 m/s), D has almost no effect on the upstream temperature distribution. The effect of longitudinal velocity on upstream temperature is stronger than that of BSEV. The downstream ceiling temperature decay model is little affected by longitudinal velocity and BSEV with D more than 1.0 m. The temperature decay rate first decreases, then increases, and finally decreases again as the D increases. Existing temperature attenuation models cannot predict the temperature profile in longitudinally ventilated tunnels with BSEV, but the temperature decay model considering fire location proposed in this paper can provide a reference value for tunnels with synergistic ventilation of longitudinal ventilation and BSEV.

Interaction between heterogeneous thermal stratification and wakes of wind turbine arrays

AbstractThe thermal heterogeneity between the land and sea might affect the wind patterns within wind farms (WF) located near seashores. This condition was modeled with a large‐eddy simulation of a numerical weather prediction model (Weather Research and Forecasting) that included the wind turbine actuator disk model (ADM). The assumed condition was that the downstream surface temperature was relatively higher (unstably stratified condition) than the neutrally stratified upstream wind. Under this condition, a thermal internal boundary layer (TIBL) was developed from an area where a step‐changed surface temperature was implemented. The combined effect of the wake deficit due to the WF and velocity recovery as a result of enhanced mixing under unstable stratification showed significant modulation of the wind speed at the hub height when local atmospheric stability affected the wind turbine (WT). We show that TIBL height depends on the variables to be evaluated as the threshold. A precise prediction of the TIBL height is beneficial for better estimation of power generation. A prediction model was proposed as an extension of the internal boundary layer (IBL) model for neutral stratification, and the results tracked TIBL development reasonably well. The effects of WFs on surface properties (e.g., friction velocity, heat flux, and Obukhov length) and the tendency of IBL growth were minor. A single WT wake was also assessed under several TIBL developmental stages (i.e., location) and thermal stratification conditions. The standard deviation of the wake deficit increased vertically during the development stage of the TIBL. In contrast, the coefficients in the horizontal and vertical directions were comparable when the WT was deep inside the TIBL.

Oxidant starvation under various operating conditions on local and transient performance of proton exchange membrane fuel cells

Oxidant starvation in proton exchange membrane fuel cells could cause severe fluctuation on dynamic performance and the significant reduction in durability. In this work, dynamic transfer and distribution characteristics of reactants and water under oxidant starvation are studied by measuring local current densities, temperatures, and the cell voltage in situ. Besides, high frequency resistance and pressure drop along the flow channel at the cathode are obtained to determine the membrane hydration state, and mass transfer and distribution. The effects of cathode humidity, cell temperature and operating modes on the local and overall transient behavior of the cell under oxidant starvation are analyzed. The experimental results show that with the air stoichiometry of 0.8, the current fluctuation distribution is much non-uniform and hydrogen pumping occurs in the downstream. When oxidant starvation occurs under potentiostatic mode, current densities in the upstream gradually increase to the steady-state; while under galvanostatic mode, local current densities in the upstream show overshoots and current variations coefficient along the flow channel are about two times of potentiostatic mode. As cell temperature increases, severe oxygen starvation occurs in the downstream and local temperature differences tend to be larger. When the unhumidified air is supplied into the cell, the combined effect of local membrane hydration state and local oxygen concentration plays a dominant role, leading to greater magnitudes of current fluctuation and higher change rate of current variation coefficient in the downstream.

Ecological responses of spawning habitat suitability to changes in flow and thermal regimes influenced by hydropower operation

AbstractLarge reservoirs and dams can fundamentally alter downstream flow and thermal regimes by resetting the flow and water temperature release boundary conditions, resulting in significant impacts on fish habitat suitability. Therefore, it is critically important to understand how the volume and temperature of dam releases to influence downstream hydraulic and temperature dynamics and predict the ecological responses of fish habitat suitability to these changes. In this study, a physically based coupled model framework was developed to identify the temporal and spatial variations of hydraulic and water temperature regimes and the spawning habitat suitability of four major Chinese carps (FMCC) in the middle reach of the Yangtze River below Three Gorges Reservoir (TGR) responded to different upstream boundary conditions established by dam operation. The results showed that the dam discharge volume from TGR mainly affected the downstream hydraulic regime, while dam discharge temperature would have most impact on downstream water temperature. The spawning habitat suitability of FMCC obviously decreased due to TGR operation, and the declined water temperature suitability and the delayed and narrowed window of suitable water temperature were the main influencing factors. For the purpose of maximizing the spawning habitat suitability of FMCC in the downstream reaches below TGR, dam discharge volume ranged from 10,000 to 22,500 m3/s, and dam discharge temperature varied from 22 to 23.5°C would be recommended as the outflow conditions in the ecological operation of TGR.

Experimental study on temperature characteristics in a subway train carriage with lateral openings in a longitudinally ventilated tunnel

Under the rapid development of subway systems, a fundamental understanding of subway fire safety is critically needed to benefit its designs and assessment. Previous studies on train carriage fires are limited to single-carriage fires under natural ventilation. However, it is still unclear how longitudinal ventilation affects the smoke movement in the train carriage with lateral openings. Therefore, a series of 1:3 reduced-scale experimental tests were conducted to investigate the smoke temperature characteristics in a train carriage located in a longitudinally ventilated tunnel. Under various fire sizes and ventilation rates, the ceiling gas temperature and smoke layer height were measured. Compared to the traditional fire scenario with end openings, the maximum ceiling gas temperature and the downstream temperature distribution decay factor are relatively smaller because of the lateral flame tilt and less heat loss during smoke propagation. The effects of ventilation velocity on the maximum ceiling gas temperature are significantly weakened under the blockage effect of the train carriage. The downstream temperature distribution followed a single exponential attenuation function, independent of the fire size and ventilation rate. However, the upstream temperature distribution is much more complex under the restriction of the end wall. A four-segment model was proposed to predict the upstream temperature distribution based on the relationship between the back-layering length and half the carriage length. The fire size and ventilation rate also show limited influence on the smoke stratification, with a layer height of 0.316 m in the stable region. The research outcomes offer adeeper understanding of the smoke propagation of the subway train carriage fire and a theoretical guide on the designs of future tunnels.

A coupled streamflow and water temperature (VIC-RBM-CE-QUAL-W2) model for the Nechako Reservoir

Study regionNechako Reservoir, British Columbia, Canada. Study focusHydrological regulation affect both hydrological and thermal conditions in the reservoir and downstream reach, subsequently disrupting fish habitats. This paper aims at developing an integrated model simulating physical processes that govern the quantity and quality of inflow, reservoir, and outflow water of the Nechako Reservoir. Such a model would help stakeholders understand the response of in-reservoir water temperature stratification and downstream water temperature to changes in inflow and reservoir operation under future climate change. New hydrological insights for the regionThe model was calibrated against historical reservoir levels and in-reservoir and outlet water temperature field data. The integrated model simulated accurately the wide variation of reservoir levels as well as the in-reservoir water temperature at Kenney Dam and the outlet temperature. Sensitivity analysis shows that reservoir water temperature particularly the epilimnion is sensitive to changes in both meteorological and hydrological forcing. Forcing the model with different outflow scenarios shows the weak sensitivity of temperature of water released to outflow rates. Given epilimnion water releases at the spillway, the Summer Temperature Management Program could be inefficient to provide cool water in the Nechako River during the critical period of salmon migration in a warming climate. However, colder water remains available at depth at Kenney Dam to potentially mitigate and better control downstream water temperature.

Effects of longitudinal wind and sidewall restriction on downstream radiative heat flux and temperature rise distribution in tunnel fires

This paper presents an experimental study on downstream radiative heat flux and temperature rise distribution of tunnel fires under the combined effects of longitudinal wind and sidewall restriction. Two fire locations, i.e., centerline fire and sidewall fire, were considered, and the wind speeds were varied between 0 and 3 m/s. The results show that under smaller ventilation velocity, the downstream radiative heat flux of sidewall fire is larger than that of centerline fire. As the ventilation velocity increases, the radiative heat flux of two fire locations both firstly increase and then decrease with increasing distance. The position of the peak radiative heat flux depends on the evolution of the flame drag and moves away from the fire center with increasing wind speed and heat release rate (HRR). Based on the solid flame assumption, thermal radiation models are proposed and validated by experimental results. A similar spacial distribution trend was observed for temperature rise with varying fire locations and wind speeds. The distance from peak temperature rise to fire center is related to the flame drag front and increases with HRR and ventilation velocity. Finally, correlations for peak temperature rise, its locations and the temperature rise attenuation beyond the peak value were established.

Experimental investigation of the burning characteristics of aviation fuel under atmospheric crosswind conditions

Pool fires caused by leaks of aviation fuels such as RP-5 can result in severe catastrophes. This problem is especially more pronounced in ships and oil tankers. Accordingly, investigation of wind-exposed pool fires is of great significance to the safety of ships. In the present study, an experimental platform was designed and constructed to study the evolutions of flame shape, burning rate, and downstream gas temperature in square aviation fuel pool fires exposed to crosswind. In this regard, different pool side lengths (D = 0.32–0.55 m) and crosswind speeds (V = 0–6.5 m/s) were analyzed. The obtained results show that as the wind speed increased, the flame length and flame tilt angle increased first and then stabilized, and the maximum values almost reached 2.5 m and 90°, respectively. Based on the force analysis, the normalized flame length (L/LV=0) and tangent of flame tilt angle (tanθ) can be expressed by the power function of Forde number (Fr). It is found that the burning rate grew steadily first, followed by a level-off value, and the maximum value is 0.0481kg/(m2.s). Accordingly, a piecewise function based on the boundary theory was proposed to estimate the burning rate. The performed analyses reveal that the downstream gas temperature increased first to a peak value (within 1000 °C) and then decreased. A modified exponential correlation of the decay of the downstream gas temperature (ΔT/ΔTpeak) with the fire distance (x/D') was developed in terms of the heat transfer balance.

Multimodel evaluation of longitudinal stream temperature gradient and dominant influencing factors in Michigan streams

AbstractStream temperature is an important determinant of fish growth, migration, and survival and can thus impact the structure and function of stream ecosystems. Many streams in Michigan and elsewhere in North America receive groundwater inputs that help regulate instream conditions by stabilizing discharge as well as stream temperature. However, groundwater withdrawal can cause reductions in streamflow which typically results in increased summer stream temperatures. Other atmospheric and hydrologic variables (i.e., overland discharge) also impact the rate at which stream temperature changes as it flows downstream. We deployed paired up‐ and downstream water pressure and temperature loggers within 21 stream reaches throughout the state of Michigan to quantify and model relationships between stream discharge, air temperature, and longitudinal change in stream temperature (i.e., temperature gradient). Using multimodel selection criteria, we evaluated the performance of a hierarchical suite of models that predict temperature gradient as a function of potential driving variables. The multimodel selection criteria identified a best‐fitting model that was able to model the diurnal, seasonal, and annual variations in rates of longitudinal temperature fluctuations across most sample streams. Partial regression analysis indicated that proxy variables representing solar radiation at the stream surface were generally the most influential predictors of longitudinal changes in stream temperature, but air temperature and components of streamflow including groundwater input were significant predictors and important in many streams.

Influence of the impoundment of the Three Gorges Reservoir on hydrothermal conditions for fish habitat in the Yangtze River.

The thermal regimes of rivers play an important role in the overall health of aquatic ecosystems. Modifications to water temperature regimes resulting from dams and reservoirs have important consequences for river ecosystems. This study investigates the impacts of the impoundment of the Three Gorges Reservoir (TGR) on the water temperature regime of fish spawning habitats in the middle reach of the Yangtze River, China. Mike 11 model is used to analyze the temporal and spatial variation of water temperatures of the expanse of 400 km along the river, from Yichang to Chenglingji. The water temperature alterations caused by the operation of the TGR are assessed with river temperature metrics. The impact on spawning habitats due to water temperature variation was also discussed in different impoundments of the TGR. The results show that the TGR has significantly altered the downstream water temperature regime, affecting the baseline deviation and phase shift of the water temperature. Such impacts on the thermal regime of the river varied with the impoundment level. The effects of the TGR on the water temperature regime decreased as the distance from the structure to the sample site increased. The water temperature regime alterations have led to the delay of the spawning times of the four famous major carp (FFMC) species. The results could be used to identify the magnitudes of water temperature alterations induced by reservoirs in the Yangtze River and provide useful information to design ecological operations for the protection of river ecosystem integrity in regulated rivers.

Using the ERA5 and ERA5-Land reanalysis datasets for river water temperature modelling in a data-scarce region

It has become apparent in recent decades that river water temperature can have immediate and lasting impacts on aquatic organisms and their lotic habitat. In rivers that are dammed, there is an opportunity and a responsibility to regulate flows in order to control these temperatures to ensure the survival of the fish and other aquatic life. This paper uses a physically based hydraulic model (HEC-RAS) to run a water temperature component, allowing the thermal model to simulate water temperatures at the same hourly time step as the hydraulic model in a data-sparse region using two meteorological reanalysis datasets (ERA5 and ERA5-Land) as inputs allowing for a full representation of the diurnal cycle. This was achieved by making use of the HEC-RAS controller to automate the calibration and subsequent simulation processes. Results show that these products are able to provide high-quality thermal simulations on a 200 km river system in British Columbia, Canada, obtaining mean absolute errors in validation of 0.66 °C and a root mean square error of 0.84 °C. Some of the boundary conditions seemed to have little effect on downstream water temperatures. This is due to the measured point of interest being far enough downstream of the dam that a thermal equilibrium is reached well before. Simulations using shorter river reaches confirm that long lakes in the study region contribute to the thermal equilibrium being attained. There also seems to be a limit to the advantage conveyed by increased spatial density of the data, as results indicate a form of skill plateau after a certain input data density is attained.

Large-Eddy Simulation of two secondary air supply strategies in kraft recovery boilers

Kraft recovery boilers are large scale combustion applications operating on black liquor, a common side-product of the pulp industry. Here, a simplified boiler model utilizing Computational Fluid Dynamics (CFD) with Large-Eddy Simulation (LES) and Lagrangian Particle Tracking (LPT) is explored to better understand the secondary air supply system and the dispersion of sprayed droplets. The unsteady nature of the air jets and droplet dispersion in such context advocates the usage of scale-resolving simulations such as LES. In the present exploratory study, the usage of LES in recovery boiler air jet simulations is piloted for the first time. The air supply system is modeled as high-momentum-flux jets injected to a uniform cross-flow. First, the set-up was verified by performing a mesh sensitivity study. The main observed global flow features included the mixing zones, wall jet and jet impact regions, jet bending in cross-flow, and reverse flow downstream of the jets. Two different engineering relevant air supply systems, a staggered and an in-line configuration, were studied and compared in terms of mixing and droplet dispersion. The main findings of the present study are as follows. First, out of the two studied configurations, the staggered one was observed to provide a more uniform downstream temperature field. Second, the in-line configuration was noted to outperform the staggered configuration in droplet dispersion by having 22% less spray-wall impingement and 15% more droplets landing at the bottom of the furnace. Third, different modes for droplet trajectories were identified based on the global flow structures.

Larval fish sensitivity to a simulated cold-water pulse varies between species and age

The release of cold-water from hypolimnetic zones of impoundments sharply reduces downstream riverine water temperature. This cold-water pollution (CWP) can extend for hundreds of kilometres, severely challenging the physiological ability of aquatic fauna, particularly ectotherms such as fish, to maintain essential processes such as metabolism, development and growth and survival. The impact of CWP on native fish, especially early life stages, is poorly known. We investigated the effect of a 24-hour exposure to a range of environmentally-related water temperatures (8, 10, 12, 14, 16, 18 and 20°C) on three age-classes (<24-hour-old, 7-day and 14-day-old larvae) of two Australian native fish species: Murray cod (Maccullochella peelii) and Macquarie perch (Macquaria australasica). Overall, larvae of M. peelii were more sensitive to lower water temperatures and hence CWP than M. australasica, indicated by higher rates of equilibrium loss. Larvae of M. peelii were most sensitive to exposure at seven days old whereas M. australasica larvae were most sensitive at <24-h-old. Using our results, we modelled pre- and post-impoundment temperature scenarios and estimated the downstream CWP footprint for both species in an Australian river reach. Larvae of M. peelii were predicted to be absent from the first 26 km of river downstream of the impoundment compared with no impact on the distribution of M. australasica. Managing riverine water temperature below impoundments is fundamental to promoting positive outcomes for endemic fish on not only a local, but global basis. This study emphasises the differential impact of CWP among the critical early life stages and fish species and highlights the urgent need to better manage hypolimnetic water releases to improve downstream river ecosystems.

Variable wildfire impacts on the seasonal water temperatures of western US streams: A retrospective study.

Recent increases in the burn area and severity of wildfires in the western US have raised concerns about the impact on stream water temperature–a key determinant of cold-water fish habitats. However, the effect on seasonal water temperatures of concern, including winter and summer, are not fully understood. In this study, we assessed the impact of wildfire burns at Boulder Creek (Oregon), Elk Creek (Oregon), and Gibbon River (Wyoming) watersheds on the downstream winter and summer water temperatures for the first three post-fire years. To obtain results independent of the choice of the analytical method, we evaluated the consequence of each burn using three different statistical approaches that utilize local water temperature data. Our results from the three approaches indicated that the response of water temperatures to wildfire burns varied across seasons and sites. Wildfire burns were associated with a median increase of up to 0.56°C (Standard Error; S.E. < 0.23°C) in the summer mean water temperatures (MWT) and 62 degree-day Celsius (DDC; S.E. < 20.7 DDC) in the summer accumulated degree days (ADD) for the three subsequent years across studied stream sites. Interestingly, these burns also corresponded to a median decrease of up to 0.49°C (S.E. < 0.45°C) in the winter MWT and 39 DDC (S.E. < 40.5 DDC) in the winter ADD for the same period across sites. Wildfire effects on the downstream water temperatures diminished with increasing site distance from the burn perimeter. Our analyses demonstrated that analytical methods that utilize local watershed data could be applied to evaluate fire effects on downstream water temperatures.