Effects of wildfire on stream temperatures in the Bitterroot River Basin, Montana

2011 ◽  
Vol 20 (2) ◽  
pp. 240 ◽  
Author(s):  
Shad K. Mahlum ◽  
Lisa A. Eby ◽  
Michael K. Young ◽  
Chris G. Clancy ◽  
Mike Jakober
Keyword(s):  
Water Temperature ◽  
River Basin ◽  
Natural Disturbance ◽  
Maximum Temperature ◽  
Aquatic Species ◽  
Reference Sites ◽  
Temperature Changes ◽  
High Severity ◽  
Maximum Water Temperature ◽  
Maximum Water

Wildfire is a common natural disturbance that can influence stream ecosystems. Of particular concern are increases in water temperature during and following fires, but studies of these phenomena are uncommon. We examined effects of wildfires in 2000 on maximum water temperature for a suite of second- to fourth-order streams with a range of burn severities in the Bitterroot River basin, Montana. Despite many sites burning at high severity, there were no apparent increases in maximum water temperature during the fires. One month after fire and in the subsequent year, increases in maximum water temperatures at sites within burns were 1.4–2.2°C greater than those at reference sites, with the greatest differences in July and August. Maximum temperature changes at sites >1.7 km downstream from burns did not differ from those at reference sites. Seven years after the fires, there was no evidence that maximum stream temperatures were returning to pre-fire norms. Temperature increases in these relatively large streams are likely to be long-lasting and exacerbated by climate change. These combined effects may alter the distribution of thermally sensitive aquatic species.

scholarly journals Long-term changes in the water temperature of rivers in Latvia

2016 ◽  
Vol 70 (2) ◽  
pp. 78-87 ◽  
Author(s):  
Inese Latkovska ◽  
Elga Apsīte
Keyword(s):  
Water Temperature ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Small Rivers ◽  
Positive Trend ◽  
Annual Maximum ◽  
Monitoring Period ◽  
Time Period ◽  
Maximum Water Temperature ◽  
Maximum Water

Abstract The study describes the trends of monthly mean water temperature (from May to October) and the annual maximum water temperature of the rivers in Latvia during the time period from 1945 to 2000. The results demonstrated that the mean water temperatures during the monitoring period from May to October were higher in the largest rivers (from 13.6 °C to 16.1 °C) compared to those in the smallest rivers (from 11.5 °C to 15.7 °C). Similar patterns were seen for the maximum water temperature: in large rivers from 22.9 °C to 25.7 °C, and in small rivers from 20.8 °C to 25.8 °C. Generally, lower water temperatures occurred in rivers with a high groundwater inflow rate, for example, in rivers of the Gauja basin, in particular, in the Amata River. Mann-Kendall test results demonstrated that during the monitoring period from May to October, mean water temperatures had a positive trend. However, the annual maximum temperature had a negative trend.

The increasing of maximum lake water temperature in lowland lakes of central Europe: case study of the Polish Lakeland

2019 ◽  
Vol 55 ◽  
pp. 6 ◽  
Author(s):  
Mariusz Ptak ◽  
Mariusz Sojka ◽  
Michał Kozłowski
Keyword(s):  
Cluster Analysis ◽  
Water Temperature ◽  
Warming Trend ◽  
Maximum Temperature ◽  
Average Value ◽  
Temperature Trends ◽  
Air Temperatures ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Maximum Temperatures

The paper presents the results of time-related changes in maximum temperatures in lakes. The analysis was carried out on the basis of 9 lakes located in the northern part of Poland. The analysis was based on daily water and air temperatures in the period 1971–2015. Mann–Kendall's and Sen's tests were applied to determine the directions and rates of change of maximum air and water temperatures. The average increase of maximum water temperature in analysed lakes was found to be 0.39 °C dec–1, while the warming trend of the maximum air temperature was 0.48 °C dec–1. Cluster analysis (CA) was used to group lakes characterised by similar changes of maximum water temperature. The first group included five lakes in which the values of the maximum temperature trends were 0.41 °C dec–1. In the second cluster the average value of maximum water temperature increase was smaller than in the first cluster (0.36 °C dec–1). Comparing the results of cluster analysis with morphometric data show that in the first cluster lakes are having a greater average depth, maximum depth and water transparency in comparison to the lakes of the second cluster.

Closed Cooling Water Heat Exchanger Design for Higher Tube Inlet Water Temperature

2013 ◽  
Author(s):  
Thomas J. Muldoon ◽  
Joseph A. Bruno
Keyword(s):  
Heat Exchanger ◽  
Water Temperature ◽  
Cooling Water ◽  
Maximum Temperature ◽  
Temperature Changes ◽  
Cooling Water Temperature ◽  
Heat Exchanger Design ◽  
Load Demand ◽  
Service Water ◽  
Winter Operation

When the maximum temperature of cooling water slowly increases with temperature changes and shifting climate patterns, smaller LMTD’s (log mean temperature differences) for the CCW’s to meet the same performance heat rejection. Making the issue more critical is that the peak cooling water temperatures will usually occur at the same time as peak summer load demand. A smaller LMTD means a larger heat exchanger and more effective tubing surface area. More surface, means more tubing or smaller diameter tubing. If the original LMTD was 12 °F, a 1 degree change may mean an increase of 9%. To maintain the same nozzle locations on a replacement exchanger means a smaller tube outside diameter and/or a larger shell. Such increases are necessary for the high summer load conditions with the highest inlet water temperatures. At lower water temperatures, the amount of excess thermal capability can become a performance and corrosion issue as the water flows are modulated to meet temperatures. To help reduce these problems, a design which allows operation with reduced surface at low temperatures is appropriate. The temperature approach (Cooling Water Out – Service Water In) based on the higher inlet cooling water temperature can be significantly smaller than when the CCW was originally designed. This paper will address a design configuration that will work with both higher summer temperature cooling water with the flexibility of using less water for cooler winter operation. The overall affect is less pumping power during colder months, more consistent tube velocities which will help with heat transfer, and minimization of sediment settling in the tubes due to lower velocities.

scholarly journals What causes cooling water temperature gradients in forested stream reaches?

2014 ◽  
Vol 11 (6) ◽  
pp. 6441-6472 ◽  
Author(s):  
G. Garner ◽  
I. A. Malcolm ◽  
J. P. Sadler ◽  
D. M. Hannah
Keyword(s):  
Water Temperature ◽  
Water Column ◽  
Stream Temperature ◽  
Temperature Gradients ◽  
Daily Maximum ◽  
Net Energy ◽  
Net Radiation ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Energy Gains

Abstract. Previous studies have suggested that shading by riparian vegetation may reduce maximum water temperature and provide refugia for temperature sensitive aquatic organisms. Longitudinal cooling gradients have been observed during the daytime for stream reaches shaded by coniferous trees downstream of clear cuts, or deciduous woodland downstream of open moorland. However, little is known about the energy exchange processes that drive such gradients, especially in semi-natural woodland contexts, and in the absence of potentially confounding cool groundwater inflows. To address this gap, this study quantified and modelled variability in stream temperature and heat fluxes along an upland reach of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland) where riparian landuse transitions from open moorland to semi-natural forest. Observations were made along a 1050 m reach using a spatially-distributed network of ten water temperature micro-loggers, three automatic weather stations and >200 hemispherical photographs, which were used to estimate incoming solar radiation. These data parameterised a high-resolution energy flux model, incorporating flow-routing, which predicted spatio-temporal variability in stream temperature. Variability in stream temperature was controlled largely by energy fluxes at the water column–atmosphere interface. Predominantly net energy gains occurred along the reach during daylight hours, and heat exchange across the bed-water column interface accounted for <1% of the net energy budget. For periods when daytime net radiation gains were high (under clear skies), differences between water temperature observations decreased in the streamwise direction; a maximum difference of 2.5 °C was observed between the upstream reach boundary and 1050 m downstream. Furthermore, daily maximum water temperature at 1050 m downstream was ≤1°C cooler than at the upstream reach boundary and lagged the occurrence of daily maximum water temperature upstream by >1h. Temperature gradients were not generated by cooling of stream water, but rather by a combination of reduced rates of heating in the woodland reach and advection of cooler (overnight and early morning) water from the upstream moorland catchment. Longitudinal thermal gradients were indistinct at night and on days when net radiation gains were low (under over-cast skies), thus when changes in net energy gains or losses did not vary significantly in space and time, and heat advected into the reach was reasonably consistent. The findings of the study and the modelling approach employed are useful tools for assessing optimal planting strategies for mitigating against ecologically damaging stream temperature maxima.

scholarly journals Trends in climatic variables and future reference evapotranspiration in Duero Valley (Spain)

2011 ◽  
Vol 11 (6) ◽  
pp. 1795-1805 ◽  
Author(s):  
R. Moratiel ◽  
R. L. Snyder ◽  
J. M. Durán ◽  
A. M. Tarquis
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Reference Evapotranspiration ◽  
Stomatal Resistance ◽  
Dew Point ◽  
Maximum Temperature ◽  
Net Radiation ◽  
Maximum Water ◽  
June July ◽  
The Impact

Abstract. The impact of climate change and its relation with evapotranspiration was evaluated in the Duero River Basin (Spain). The study shows possible future situations 50 yr from now from the reference evapotranspiration (ETo). The maximum temperature (Tmax), minimum temperature (Tmin), dew point (Td), wind speed (U) and net radiation (Rn) trends during the 1980–2009 period were obtained and extrapolated with the FAO-56 Penman-Montheith equation to estimate ETo. Changes in stomatal resistance in response to increases in CO2 were also considered. Four scenarios were done, taking the concentration of CO2 and the period analyzed (annual or monthly) into consideration. The scenarios studied showed the changes in ETo as a consequence of the annual and monthly trends in the variables Tmax, Tmin, Td, U and Rn with current and future CO2 concentrations (372 ppm and 550 ppm). The future ETo showed increases between 118 mm (11 %) and 55 mm (5 %) with respect to the current situation of the river basin at 1042 mm. The months most affected by climate change are May, June, July, August and September, which also coincide with the maximum water needs of the basin's crops.

scholarly journals Threats of global warming to the world’s freshwater fishes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Valerio Barbarossa ◽  
Joyce Bosmans ◽  
Niko Wanders ◽  
Henry King ◽  
Marc F. P. Bierkens ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Water Temperature ◽  
Arid Regions ◽  
Freshwater Fishes ◽  
Geographic Range ◽  
Freshwater Biodiversity ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Riverine Fish

AbstractClimate change poses a significant threat to global biodiversity, but freshwater fishes have been largely ignored in climate change assessments. Here, we assess threats of future flow and water temperature extremes to ~11,500 riverine fish species. In a 3.2 °C warmer world (no further emission cuts after current governments’ pledges for 2030), 36% of the species have over half of their present-day geographic range exposed to climatic extremes beyond current levels. Threats are largest in tropical and sub-arid regions and increases in maximum water temperature are more threatening than changes in flow extremes. In comparison, 9% of the species are projected to have more than half of their present-day geographic range threatened in a 2 °C warmer world, which further reduces to 4% of the species if warming is limited to 1.5 °C. Our results highlight the need to intensify (inter)national commitments to limit global warming if freshwater biodiversity is to be safeguarded.

scholarly journals Design and Fabrication of Solar Water Heater with CPC by using Wafers Packet

2019 ◽  
Vol 8 (3) ◽  
pp. 1175-1178
Keyword(s):  
Natural Circulation ◽  
Current System ◽  
Maximum Temperature ◽  
Prototype System ◽  
Water Heater ◽  
Small Aperture ◽  
Maximum Water Temperature ◽  
Collector Efficiency ◽  
Maximum Water ◽  
Daily Water

The objective of our project is to create a system which can heat water at maximum temperature and give more efficiency than the current system used in the market today for daily water heating purpose and also less costly which is the main factor. So we made a prototype system of less expensive material and another main material such as wafer packet which will absorbs more sunlight. The evacuated collector for natural circulation discharge through single ended water-in-glass evacuated tubes mounted over a diffuse reflector was also taken into consideration. Therefore, the concept of Compound Parabolic Collector (CPC) is used to heat the water and with a small aperture area as compared to other collectors is possible to achieve a maximum water temperature up-to 100°C. The system is of reasonable cost as compared to existing ones. Collector efficiency is nearly 65%, however if all the control about reflecting rays and insulation is used for reducing the heat loss may be efficiency increasable comparably

scholarly journals Maximum Water Temperature Limit in Open-Water Swimming Events

2014 ◽  
Vol 25 (2) ◽  
pp. 245-246
Author(s):  
Filippo Macaluso ◽  
Rosario Barone ◽  
Ashwin W. Isaacs ◽  
Felicia Farina ◽  
Giuseppe Morici ◽  
...  
Keyword(s):  
Water Temperature ◽  
Open Water ◽  
Temperature Limit ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Open Water Swimming
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