The impact of river modification and dam operation on floodplain vegetation succession trends in the Kootenai River, USA

A field demonstration project on flexible dam operation at the Managawa dam in the Kuzuryu River Basin has been implemented since 2000. The goal is to restore flow and sediment regimes in the Managawa River, which flows along the Ono-city and is located below the dam. Flexible dam operation stores inflow discharge into a reservoir, which generally uses part of the flood control capacity and appropriately discharges the stored water to the river, also known as the “flood pulse,” for restoring dynamic fluvial systems and the resulting ecological processes. In addition, other options have been carried out in combination with flexible dam operation, for example, sediment replenishment since 2003 and channel rehabilitation since 2007. This article reveals the positive impacts and effectiveness of flexible dam operation, sediment replenishment, and channel rehabilitation, and discusses challenges and future prospects toward translating the field demonstration project into dam management on the ground level. First, we classified reach types to identify the impact of various management options, e.g., flexible dam operation, sediment replenishment, and channel rehabilitation. These management options can influence respected reaches. We conducted a macro-scale analysis to understand the relationship between the aforementioned management options and dynamic fluvial systems, addressing changes in gravel riverbed, vegetation, and habitat types (riffles and pools). Second, a micro-scale analysis was conducted to understand the relationship between the management option and changes in attached algae to sediment and macro-invertebrates, etc. The results show the effectiveness of the middle-scale flood pulse to restore dynamic fluvial systems, increase habitat diversity, and sustain ecological processes. Furthermore, we discussed the impacts of such options on the flow and sediment regimes in Managawa River and revealed that flexible dam operation reduces the occurrence of low flow and midscale floods. It was also revealed methods such as sediment replenishment and channel rehabilitation play an important role in increasing the effectiveness of the middle-scale flood pulse and restoring dynamic fluvial systems, even though sediment replenishment is not sufficient to restore sediment regimes (i.e., bring then back to pre-dam conditions).

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Impacts of the Sanmenxia Dam on the Interaction between Surface Water and Groundwater in the Lower Weihe River of Yellow River Watershed

Water ◽

10.3390/w12061671 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1671 ◽

Cited By ~ 2

Author(s):

Dong Zhang ◽

Dongmei Han ◽

Xianfang Song

Keyword(s):

Surface Water ◽

Rural Areas ◽

Yellow River ◽

Early Stage ◽

Fertilizer Application ◽

River Watershed ◽

Surface Water And Groundwater ◽

Dam Operation ◽

Weihe River ◽

The Impact

Sanmenxia Dam, one of the most controversial water conservancy projects in China, has seriously impacted the lower Weihe River of the Yellow River Watershed since its operation. At the Huaxian Station, the dam operation controls the surface water level and leads to the variation of the surface water–groundwater interaction relationship. The river channel switched from a losing reach during the early stage (1959) to a gaining reach in 2010 eventually. The comparison of tracer (Cl−, δ18O and δ2H) characteristics of surface water in successive reaches with that of ambient groundwater shows that the general interaction condition is obviously affected by the dam operation and the impact area can be tracked back to Weinan City, around 65 km upstream of the estuary of the Weihe River. The anthropogenic inputs (i.e., agricultural fertilizer application, wastewater discharge, and rural industrial sewage) could be responsible for the deterioration of hydro-environment during the investigation periods of 2015 and 2016, as the population and fertilizer consumption escalated in the last 60 years. The use of contaminated river water for irrigation, along with the dissolved fertilizer inputs, can affect the groundwater quality, in particular resulting in the NO3− concentrations ranging from 139.4 to 374.1 mg/L. The unregulated industrial inputs in some rural areas may increase the Cl− contents in groundwater ranging from 298.4 to 472.9 mg/L. The findings are helpful for the improved comprehensive understanding of impacts of the Sanmenxia Dam on the interaction between surface water and groundwater, and for improving local water resources management.

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Vegetation-Groundwater Relationship Model for Subei Lake Watershed and Prediction of Vegetation Succession Rules under Exploitation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.4315 ◽

2012 ◽

Vol 518-523 ◽

pp. 4315-4320

Author(s):

Ying Li ◽

Gui Zhang Zhao ◽

Lei Zeng ◽

Cun Liang Wang

Keyword(s):

Groundwater Level ◽

Aquatic Vegetation ◽

Vegetation Succession ◽

Burial Depth ◽

Exploitation And Utilization ◽

Numeric Simulation ◽

Relationship Model ◽

Salix Matsudana ◽

Semi Arid Region ◽

The Impact

Located in an arid and semi-arid region with low rainfall and high evaporation, the Subei Lake watershed has fragile ecological environment; the impact of groundwater level recession on vegetation ecology is the key problem for the exploitation and utilization of groundwater resource in this region. In this paper, a succession model for vegetation and burial depth of groundwater level was constructed through field survey, and was used along with numeric simulation to predict the change in burial depth of groundwater level in the study area under exploitation and to analyze and predict the vegetation succession rules and processes. It is believed from the study that, while groundwater level falls constantly, the burial depth of groundwater level will increase gradually, and succession will occur gradually from aquatic vegetation to mesophytic and xerophytic vegetations, from Carex L. and Iris ensata Thunb shoaly lands to Achnatherum splendens shoaly lands, from Salix psammophila shrubs to Artemisia desterorum Spreng shrubs, and from Populus simonii to Salix matsudana.

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THE IMPACT OF FLOODPLAIN VEGETATION ON THE EROSION-SEDIMENTATION PROCESSES IN FLUVISOLS DURING FLOOD EVENTS

Applied Ecology and Environmental Research ◽

10.15666/aeer/1703_63496374 ◽

2019 ◽

Vol 17 (3) ◽

Cited By ~ 3

Author(s):

I BELČÁKOVÁ

Keyword(s):

Flood Events ◽

Floodplain Vegetation ◽

The Impact ◽

Sedimentation Processes

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Climate change impact to dam Operation, case study of Darma Dam, West Java

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1212/1/012031 ◽

2022 ◽

Vol 1212 (1) ◽

pp. 012031

Author(s):

A A Kuntoro ◽

D T Ramadhani ◽

A M S Idris ◽

M Farid ◽

M B Adityawan ◽

...

Keyword(s):

Climate Change ◽

Present Condition ◽

Water Volume ◽

Adaptation To Climate Change ◽

Wet Season ◽

West Java ◽

Industrial Sectors ◽

Dam Operation ◽

Average Water ◽

The Impact

Abstract Darma Dam is located in the upstream of Cisanggarung River, Kuningan Regency, West Java Province. Darma Dam construction dated from about 1922. Indonesian government continued the construction and began operating in 1962. With effective storage of about 40 million m3, Darma Dam provides water for about 22 thousand irrigation areas and bulk water for several cities and regencies. Several problems encountered in Darma Dam operation and water management are 1) increasing water demand from domestic and industrial sectors, and 2) high inflow variation during the dry and wet season, resulting in a large amount of water spill from the dam spillway. This paper addressed the impact of climate change on the inflow variation of Darma Dam in the dry and wet seasons. Further analysis shows average water spills from the spillway during the wet season may increase from about 12 million m3/year in the present condition to about 20 million m3/year in 2020-2050, while the average water volume during the dry season may reduce from 22.5 million m3 in the present condition to about 20.7 million m3 in 2020-2050. This study suggests that dam operation need adjustment in the future as part of adaptation to climate change.

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Impacts of Upstream Structures on Downstream Discharge in the Transboundary Imjin River Basin, Korean Peninsula

Applied Sciences ◽

10.3390/app10093333 ◽

2020 ◽

Vol 10 (9) ◽

pp. 3333

Author(s):

Doan Thi Thu Ha ◽

Seon-Ho Kim ◽

Deg-Hyo Bae

Keyword(s):

River Basin ◽

Korean Peninsula ◽

Water Levels ◽

Dam Failure ◽

Water Release ◽

Transboundary River Basin ◽

Operational Rule ◽

Dam Operation ◽

Effective Use ◽

The Impact

The transboundary river basin is a great challenge for water management and disaster reduction due to its specific characteristics. In this study, upstream impacts from natural and artificial sources on the downstream discharge on the Imjin river basin, the well-known transboundary region in the Korean peninsula, were evaluated using a hydrological model integrating a dam operation module at an hourly timescale. The module uses a concept of the AutoROM method as the operational rule to update the dam storage and decide water release. Dam storages were translated into water levels using a water level–storage curve. To quantify the impact of hydraulic structures on the Northern Imjin river basin, change in discharge was analyzed in four flood events (2009, 2010, 2011, and 2012). Dam failure scenarios were developed under conditions of the 2010 flood event, in which the releases of 100%, 80%, 50%, and 20% of water storage of Hwanggang dam were simulated. The results indicate that the amount of water released from upstream dams is the main cause of floods in the downstream region. To reduce the risk of floods in the downstream river basin, an optimal dam operation module and information on upstream dams play an important role and contribute to the effective use of water resources.

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Changes in Floodplain Vegetation Density and the Impact of Invasive Amorpha fruticosa on Flood Conveyance

Journal of Environmental Geography ◽

10.2478/jengeo-2018-0008 ◽

2018 ◽

Vol 11 (3-4) ◽

pp. 3-12 ◽

Cited By ~ 1

Author(s):

Judit Nagy ◽

Tímea Kiss ◽

István Fehérváry ◽

Csaba Vaszkó

Keyword(s):

Land Use ◽

Riparian Forests ◽

Vegetation Density ◽

Floodplain Vegetation ◽

Amorpha Fruticosa ◽

Dense Vegetation ◽

Flood Level ◽

The Impact ◽

Peak Flood

Abstract Flood conveyance of floodplains is significantly influenced by the riparian vegetation cover, since vegetation affects flow velocity, therefore has a considerable impact on flood height and rate and pattern of sedimentation. However, climate change promotes the spread of invasive species, and their rapid growth results in dense vegetation stands, thus they have a significant impact on floodwater hydraulics. The aims of the present study are (1) to analyse the long-term changes in land-use and vegetation density on the Lower Tisza River, (2) to evaluate the role of the invasive Amorpha fruticosa in increasing vegetation density, and (3) to model the effect of dense floodplain vegetation on flood level and flood conveyance. Long-term (1784-2017) changes of land-use suggest that in natural conditions the study area was occupied by wetlands (92%), thus water covered the area for almost the whole year. In the 19th century, after levee constructions the wetlands were replaced by meadows and pastures (94%), then by the end of the 20th century planted and riparian forests replaced these land-covers. As a result, the mean roughness (0.14) of the floodplain has increased threefold until the early 21st century. Today forests are invaded by Amorpha fruticosa, which increases the vegetation density by 3% in riparian forests, by 23% in forest plantations, and by up to 100% in abandoned pastures and a rable lands. According to the results of HEC-RAS (Hydrologic Engineering Center’s River Analysis System) and CES (Conveyance Estimation System) models, if floodplain vegetation was managed and Amorpha fruticosa was cleared from the floodplain, peak flood level would decrease by 15 cm. Due to dense vegetation, the flood conveyance decreased by 4-6%, and the presence of Amorpha fruticosa reduced the flood flow velocities by 0.014-0.016 m/s. Accordingly, clearance of the floodplain from Amorpha fruticosa would have positive effects on flood protection, since peak flood stages would decrease and flood waves would shorten.

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Temporal variation in fish community in the tailrace at Três Marias Hydroelectric Dam, São Francisco River, Brazil

Neotropical Ichthyology ◽

10.1590/s1679-62252012000400006 ◽

2012 ◽

Vol 10 (4) ◽

pp. 731-740 ◽

Cited By ~ 9

Author(s):

Raquel Coelho Loures ◽

Paulo Santos Pompeu

Keyword(s):

Temporal Variation ◽

Fish Community ◽

Migratory Species ◽

Wet Season ◽

Negative Effects ◽

Hydroelectric Energy ◽

Hydroelectric Dam ◽

Dam Operation ◽

The Impact ◽

The Relationship

Damming rivers to generate hydroelectric energy causes a series of changes in the environment, including impacts on the ichthyofauna. Knowledge of the fish community immediately downstream from a hydroelectric dam can help to reduce the negative effects of dam operation, such as fish entrance into the draft tube during turbines maintenance. We evaluated the temporal variation in fish community composition and abundance, near Três Marias Hydroelectric Dam (TMD), and its relationship with abiotic variables. Samples (n = 18) were carried out using gill nets in the tailrace of the dam, over the course of a hydrological year, at six time points during a 24-hour period. Abiotic data were also sampled to assess the relationship with the biotic data. In the tailrace, Characiformes showed the highest richness, while Siluriformes were the most abundant. Of the 33 species sampled, six were migratory. The fish community was significantly different between the dry and wet seasons, with higher abundances during the wet season. In the wet season, the frequency of migratory species in the community rose from 0.7 to 18.3%, and Pimelodus maculatus accounted for 14.5% of the overall abundance. We observed that Characiformes captures occurred mainly in the morning, with peak activity between 5:00 and 9:00 h. Siluriformes showed greater nocturnal activity and were largely captured between 17:00 and 21:00 h. Synchronizing operational maneuvers that represent high risk to the fish with periods of low abundance in the tailrace, i.e., during months of low precipitation, may be a measure to reduce the impact of the operation on the downstream fish community.

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