Related Experiment Video
Updated: Mar 11, 2026
12:44
Watershed Planning within a Quantitative Scenario Analysis Framework
Published on: July 24, 2016
8.7K
Spatial and temporal dynamics of macrophyte cover in a large regulated river
A Tena1, D Vericat2, L E Gonzalo1
1Fluvial Dynamics Research Group (RIUS), University of Lleida, Lleida, Catalonia, Spain.
Journal of Environmental Management
|November 29, 2016
Summary
Dams in the Ebro River have promoted aquatic macrophyte growth by altering flow and sediment. Macrophyte cover increased over time, enhancing riverbed stability and necessitating improved flow management strategies.
Area of Science:
- Riverine ecology
- Environmental science
- Hydrology
Background:
- River Ebro basin extensively dammed, altering flow regimes, bed stability, and water clarity.
- These changes create optimal conditions for aquatic macrophyte proliferation.
- Macrophytes impact river geomorphology and ecosystem functioning.
Purpose of the Study:
- Analyze temporal and spatial changes in macrophyte cover in the lowermost Ebro River.
- Investigate the relationship between macrophyte distribution and flow hydraulics, channel geometry, and sedimentology.
- Evaluate the impact of natural floods and artificial flushing flows on macrophyte cover.
Main Methods:
- Series of field campaigns conducted between 2009 and 2010.
- Spatial analysis of macrophyte distribution in relation to hydraulic and geomorphological factors.
- Temporal analysis of macrophyte cover changes in response to flow events.
Main Results:
- Macrophyte cover showed a variable spatial pattern, with highest densities in riffles and lowest in pools.
- Water depth and riverbed grain-size distribution (D84) were key factors controlling plant cover.
- Macrophyte proportion increased from spring to autumn, reaching 40% channel surface cover.
- Despite flushing flows, mean macrophyte cover increased by 19% over the study period, enhancing riverbed stability.
Conclusions:
- Macrophyte proliferation in the Ebro River is significantly influenced by dam-induced hydrological alterations.
- Existing management strategies, such as flushing flows, have limited long-term effectiveness in controlling macrophyte growth.
- Improved management is necessary, including complementary measures like pre-flow discharge reduction, mechanical removal, and increased winter flood frequency.
Related Concept Videos
01:24Rapidly Varying Flow
585
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
585
02:41Responses to Drought and Flooding
12.3K
Water plays a significant role in the life cycle of plants. However, insufficient or excess of water can be detrimental and pose a serious threat to plants.
12.3K
01:30Typical Model Studies
667
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
667
01:17Design Example: Analyzing Capacity Contours for Flood Risk Assessment
347
Flood risk assessment involves careful planning and analysis to ensure the safety of communities near water retention structures. Capacity contours are a vital tool in this process, as they illustrate the potential spread of water at specific levels in a given area. In the context of building a bund across a small valley, these contours play a critical role in evaluating the safety of nearby residential areas.In this example, the bund is intended to store stormwater in the valley. The engineers...
347