Statistical summaries of Michigan streamflow data, duration hydrographs and summaries of flow duration, low flow, high flow, and monthly and annual mean discharge through September 1967

1970 ◽  
Author(s):  
R.L. Knutilla
Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 212 ◽  
Author(s):  
Zhipeng Xu ◽  
Wenfei Liu ◽  
Xiaohua Wei ◽  
Houbao Fan ◽  
Yizao Ge ◽  
...  

Fruit tree planting is a common practice for alleviating poverty and restoring degraded environment in developing countries. Yet, its environmental effects are rarely assessed. The Jiujushui watershed (261.4 km2), located in the subtropical Jiangxi Province of China, was selected to assess responses of several flow regime components on both reforestation and fruit tree planting. Three periods of forest changes, including a reference (1961 to 1985), reforestation (1986 to 2000) and fruit tree planting (2001 to 2016) were identified for assessment. Results suggest that the reforestation significantly decreased the average magnitude of high flow by 8.78%, and shortened high flow duration by 2.2 days compared with the reference. In contrast, fruit tree planting significantly increased the average magnitude of high flow by 27.43%. For low flows, reforestation significantly increased the average magnitude by 46.38%, and shortened low flow duration by 8.8 days, while the fruit tree planting had no significant impact on any flow regime components of low flows. We conclude that reforestation had positive impacts on high and low flows, while to our surprise, fruit tree planting had negative effects on high flows, suggesting that large areas of fruit tree planting may potentially become an important driver for some negative hydrological effects in our study area.


2012 ◽  
Vol 16 (7) ◽  
pp. 2035-2047 ◽  
Author(s):  
K. Stahl ◽  
L. M. Tallaksen ◽  
J. Hannaford ◽  
H. A. J. van Lanen

Abstract. An overall appraisal of runoff changes at the European scale has been hindered by "white space" on maps of observed trends due to a paucity of readily-available streamflow data. This study tested whether this white space can be filled using estimates of trends derived from model simulations of European runoff. The simulations stem from an ensemble of eight global hydrological models that were forced with the same climate input for the period 1963–2000. The derived trends were validated for 293 grid cells across the European domain with observation-based trend estimates. The ensemble mean overall provided the best representation of trends in the observations. Maps of trends in annual runoff based on the ensemble mean demonstrated a pronounced continental dipole pattern of positive trends in western and northern Europe and negative trends in southern and parts of eastern Europe, which has not previously been demonstrated and discussed in comparable detail. Overall, positive trends in annual streamflow appear to reflect the marked wetting trends of the winter months, whereas negative annual trends result primarily from a widespread decrease in streamflow in spring and summer months, consistent with a decrease in summer low flow in large parts of Europe. High flow appears to have increased in rain-dominated hydrological regimes, whereas an inconsistent or decreasing signal was found in snow-dominated regimes. The different models agreed on the predominant continental-scale pattern of trends, but in some areas disagreed on the magnitude and even the direction of trends, particularly in transition zones between regions with increasing and decreasing runoff trends, in complex terrain with a high spatial variability, and in snow-dominated regimes. Model estimates appeared most reliable in reproducing observed trends in annual runoff, winter runoff, and 7-day high flow. Modelled trends in runoff during the summer months, spring (for snow influenced regions) and autumn, and trends in summer low flow were more variable – both among models and in the spatial patterns of agreement between models and the observations. The use of models to display changes in these hydrological characteristics should therefore be viewed with caution due to higher uncertainty.


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 338 ◽  
Author(s):  
Halil Ibrahim Burgan ◽  
Hafzullah Aksoy

Flow duration curve (FDC) is widely used in hydrology to assess streamflow in a river basin. In this study, a simple FDC model is developed for monthly streamflow data. The model consists of several steps including the nondimensionalization and then normalization in case the monthly streamflow data do not fit the normal probability distribution function. The normalized quantiles are calculated after which a back transformation is applied to the normalized quantiles to return back to the original dimensional streamflow data. In order to calculate annual streamflow of the river basin, an empirical regression equation is proposed using the drainage area and the annual total precipitation only as the input. As the final step of the model, dimensional quantiles of FDC are calculated. Ceyhan River basin in southern Turkey is chosen for the case study. Forty-two streamflow gauging stations are considered; two thirds of the gauging stations are used for the model calibration, and one third for validation. The modeled FDCs are compared to the observation and assessed with a number of performance metrics. They are found similar to the observed ones with a relatively good performance; they are good in the mid and high flow parts particularly while the low flow part of FDCs might require further detailed analysis.


2021 ◽  
Author(s):  
Florian Caillon ◽  
Katharina Besemer ◽  
Peter Peduzzi ◽  
Jakob Schelker

AbstractFlood events are now recognized as potentially important occasions for the transfer of soil microbes to stream ecosystems. Yet, little is known about these “dynamic pulses of microbial life” for stream bacterial community composition (BCC) and diversity. In this study, we explored the potential alteration of stream BCC by soil inoculation during high flow events in six pre-alpine first order streams and the larger Oberer Seebach. During 1 year, we compared variations of BCC in soil water, stream water and in benthic biofilms at different flow conditions (low to intermediate flows versus high flow). Bacterial diversity was lowest in biofilms, followed by soils and highest in headwater streams and the Oberer Seebach. In headwater streams, bacterial diversity was significantly higher during high flow, as compared to low flow (Shannon diversity: 7.6 versus 7.9 at low versus high flow, respectively, p < 0.001). Approximately 70% of the bacterial operational taxonomic units (OTUs) from streams and stream biofilms were the same as in soil water, while in the latter one third of the OTUs were specific to high flow conditions. These soil high-flow OTUs were also found in streams and biofilms at other times of the year. These results demonstrate the relevance of floods in generating short and reoccurring inoculation events for flowing waters. Moreover, they show that soil microbial inoculation during high flow enhances microbial diversity and shapes fluvial BCC even during low flow. Hence, soil microbial inoculation during floods could act as a previously overlooked driver of microbial diversity in headwater streams.


CORROSION ◽  
1959 ◽  
Vol 15 (4) ◽  
pp. 29-32
Author(s):  
M. KRULFELD ◽  
M. C. BLOOM ◽  
R. E. SEEBOLD

Abstract A method of applying the hydrogen effusion method to the measurement of corrosion rates in dynamic aqueous systems at elevated temperature and pressure is described. Data obtained in low carbon steel systems are presented, including (1) reproducibility obtained in measured hydrogen effusion rates at a flow velocity of 1 foot per second at a temperature of 600 F and 2000 psi, and (2) a quantitative comparison between the hydrogen effusion rates in static and in low flow velocity dynamic systems at this temperature and pressure. Some observations are included on corrosion rate measurements in a high flow velocity (30 feet per second) loop by the hydrogen effusion method. Implications of these measurements with regard to the comparison between high flow velocity corrosion and low flow velocity corrosion are mentioned and some data indicating high local sensitivity of the hydrogen effusion method are noted. Some possible difficulties involved in the method are pointed out. 2.3.4


Sign in / Sign up

Export Citation Format

Share Document