Effects of low flow and co-occurring stressors on structural and functional characteristics of the benthic biofilm in small streams

2020 ◽  
Vol 733 ◽  
pp. 139331 ◽  
Author(s):  
Annette Baattrup-Pedersen ◽  
Daniel Graeber ◽  
Helena Kallestrup ◽  
Kun Guo ◽  
Jes Jessen Rasmussen ◽  
...  
Keyword(s):  
Low Flow ◽  
Functional Characteristics ◽  
Small Streams

scholarly journals Distribution of Agonostomus monticola and Brycon behreae in the Río Grande de Térraba, Costa Rica and relations with water flow

2010 ◽  
Vol 8 (4) ◽  
pp. 841-849 ◽  
Author(s):  
Thiago Cotta Ribeiro ◽  
Gerardo Umaña Villalobos
Keyword(s):  
Costa Rica ◽  
Peak Flow ◽  
Low Flow ◽  
Main Stream ◽  
Main River ◽  
Small Streams ◽  
Study Population ◽  
June July ◽  
Fish Habitats ◽  
Made In

Fish monthly samples were made in three tributaries and in the main stream in order to study population dynamics and the influence of flow on abundance of Agonostomus monticola (Mugilidae) and Brycon behreae (Characidae) in the basin of Térraba River Basin (Costa Rica). Flow was seasonal in these rivers, with peak flow in October. Recruitment was different among the species, B. behreae recruited from January to June and A. monticola all year round with a peak in June-July and October-November. Juveniles were more abundant in smaller streams. Abundance was higher in general during low flow and low turbidity periods. The results suggest that the streams have an important role in the maintenance of both species in the ecosystem, where juveniles can use the streams as nursing habitats during their development, allowing these small streams to be considered as essential fish habitats. Also, it was determined that the increased volume and turbidity of water can significantly affect the proportion of adults and juveniles between the main river and its tributaries.

Nutrient retention efficiency of small regulated streams during the season of low-flow regime in Central Lithuanian lowland

2013 ◽  
Vol 45 (3) ◽  
pp. 357-367 ◽  
Author(s):  
Valerijus Gasiūnas ◽  
Jelena Lysovienė
Keyword(s):  
Flow Regime ◽  
Empirical Equation ◽  
Nutrient Retention ◽  
Low Flow ◽  
Treated Wastewater ◽  
Pollution Load ◽  
Retention Efficiency ◽  
Total N ◽  
Small Streams ◽  
Total P

Small streams are polluted with nutrients when crude or partially treated wastewater flows from settlements. The aim of the study was to determine the efficiency of small streams to self-purify themselves of nutrients during the season of low-flow regime. The study was carried out in five regulated streams with catchments of up to 30 km2 in the Central Lithuanian lowland. The retention of nitrogen (N) and phosphorus (P) compounds was studied up to 5.2 km downstream from the settlements. Owing to the pollution load from settlements, the concentrations of total N increased from 2.0–3.0 above the settlements to 6.75 ± 2.07 mg L−1 below; the concentrations of total P increased from 0.03–0.07 to 0.56 ± 0.30 mg L−1, with the stream's ecological state deteriorating to ‘poor’ and ‘bad’. For the calculation of total N retention, with respect to the pollution load and the distance from the settlement, an empirical equation was derived. Calculations show that with a pollution load of 2.0 g N m−3 at 5.0 km distance, around 90% of total N can be retained. However, when the load is threefold greater, at the same distance only 65% of total N is retained. As a result of self-purification processes only about 50% of total P may be retained.

scholarly journals Key Planning Questions to Consider in Small Stream Hydrometric Monitoring

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Robin Pike ◽  
Neil Goeller ◽  
Jonathan Goetz ◽  
Sarah Crookshanks
Keyword(s):  
Flow Measurement ◽  
Data Availability ◽  
Low Flow ◽  
Small Stream ◽  
Equipment Availability ◽  
Small Streams ◽  
Standard Operating ◽  
Channel Control ◽  
Hydrometric Station ◽  
Key Questions

This article provides key questions to consider when planning and operating a small stream hydrometric station. Office planning components include defining hydrometric monitoring objectives; the availability of hydrometric expertise; resource availability; safety plans and standard operating procedures; equipment availability (hydrometric station installation and streamflow measurement); sampling frequency and data availability; permissions and permitting requirements; data processing, access, and archiving; and metadata requirements. Key parts of field-based hydrometric planning include site safety; site accessibility; flow variability; channel control features; flow containment, diversions and additions; low flow considerations; high flow considerations; flow measurement challenges in small streams; benchmarks and survey criteria; and public safety and vandalism. Theoverall  goal of the article is to help non-professionals collect better hydrometric data and to highlight the varied planning aspects of typical hydrometric installations and operations.

Flow trends in Western Hungary

2020 ◽  
Author(s):  
Kevin Mátyás ◽  
Katalin Bene ◽  
Róbert Koch
Keyword(s):  
Water Resources ◽  
River Basin Management ◽  
High Flow ◽  
Low Flow ◽  
Full Time ◽  
Available Water ◽  
Time Period ◽  
Small Streams ◽  
Time Periods ◽  
The Individual

<p>Knowledge of available water resources is essential in water management and water policy. In accordance with the EU Water Framework Directive, Hungary reviews and updates its assessment of water balance through the River Basin Management Plan (RBMP) every 7 years. In many cases, the available water resources in the RBMP for small streams are based on expert judgment, since it is not always possible to measure the actual water level or discharge. Consideration of climate change and its effects is also a big question: what are the effects of these changes on small streams, and is there a trend in the runoff?</p><p>For water managers, water scarcity and abundance are major concerns. To address this issue, our study focused on high-flow and low-flow signatures. This paper presents flow trends during the last 36 years in Western Hungary. During the period 1980-2016, daily discharge measurements were collected at 74 small streams. Twelve flow signatures were selected for trend analyses. Trends were determined for three time periods: the full measured time period at each station, and two eighteen-year periods between 1980-1998 and 1999-2016. At each location, trends were determined with 10% significance using the Mann-Kendall test.</p><p>The results show that in the low-flow signatures, no significant changes in flow trends occur at the individual watershed and regional scales during the two eighteen-year time periods, as well as during the full time period. In contrast, high-flow signatures have significantly changed for all three time periods, at both the individual and regional scales.</p><p>This work was undertaken as part of a project funded by the EFOP-3.6.1-16-2016-00017.</p>

scholarly journals Hydrogeological approach to the regional analysis of low flow in medium and small streams of the hilly and mountainous areas of Serbia

2006 ◽  
pp. 9-28
Author(s):  
Zoran Nikic
Keyword(s):  
Regional Analysis ◽  
Low Flow ◽  
Small Rivers ◽  
Medium Size ◽  
Analysis Method ◽  
Independent Variables ◽  
Small Streams ◽  
Catchment Areas ◽  
Dependent Variables

During the long rainless spells of the dry season, flows in medium and small streams get reduced to what is generally known as "low flow". For ungauged streams, the controlling "low flows" are determined using the regional analysis method. In the presently described exploration, the method applied was based on the assumption that dry weather discharges in medium and small rivers depended on the hydrogeological conditions. The controlling effect of hydrogeology on the natural low flow in medium and small streams of the hilly and mountainous part of Serbia was analyzed applying the theory of multiple linear regression. The thirty-day minimum mean 80 and 95 per cent exceedance flows were taken for dependent variables, and quantified hydrogeological elements as independent variables. The analysis covered streams that had small or medium size catchment areas. The treated example encompassed sixty-one gauged catchments. The resulting regional relations for the thirty day minimum mean 80 and 95 per cent exceedance flows are presented in this paper. The quality of the established relation was controlled by relevant statistic tests.

scholarly journals A Consideration of the Estimation of the Design Flood for Small Basin in Gangwon Yeongdong Region

2020 ◽  
Vol 20 (5) ◽  
pp. 33-45
Author(s):  
Young Jun Kim ◽  
Dong Ho Kang ◽  
Byung Sik Kim
Keyword(s):  
Human Life ◽  
Estimation Method ◽  
Small River ◽  
Low Flow ◽  
Design Flood ◽  
Tracking Method ◽  
Flood Volume ◽  
Small Streams ◽  
Flood Estimation ◽  
Small River Basin

Due to the recent increase in heavy localized rain caused by climate change, the risk of flooding in mountainous areas and small streams is growing daily. To prevent damage to human life and property, it is necessary to accurately estimate the amount of design flood in the small river basin. Recently, the Standard Guidelines for Flood Estimation (Ministry of Environment, 2019) have been proposed to reduce uncertainties such as the subjective interpretations of engineers, which differ in the flood dischargeestimation, and to ensure a certain level of uniformity. However, in the case of Gangwon region,where the watershed area is small and the channel slope is steep, it is necessary to carefully approach the application of Clark’s watershed tracking method, suggested in the standard guidelines. As Gangwon-Yeongdong region is expected to be more sensitive to localized heavy rainfall due to the influence of the Taebaek Mountains andhas a relatively steeper watershed mean slope and euro slope than other regions, this study compares and analyzes the results of Clark’s basin tracking method and the “rational method”, to derive a more reasonable flood calculation method. Additionally, it suggests an appropriate flood discharge estimation method for the small river in Gangwon-Yeongdong region. Consequently, the flood amount can reasonably be calculated by applying a rational formula rather than Clark’sbasin tracking method, in which the flood volume is underestimated, when calculating the flood volume of a small river in Yeongdong, Gangwon Province, which has a low flow effect of less than 5 km<sup>2</sup>.

951: “Experience in the Treatment of Low Flow Priapism”; A Novel, Easy and Effective Technique: A Long-Term, Binational, Multi-Institutional Study in 18 Patients Over 8 Years

2007 ◽  
Vol 177 (4S) ◽  
pp. 314-315
Author(s):  
Jose A. Medina Machuca ◽  
Jose A. Medina Coello ◽  
Hugo Manzanilla ◽  
Francisco A. Gutierrez
Keyword(s):  
Low Flow ◽  
Effective Technique
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