Geomorphic and vegetation changes in a meandering dryland river regulated by a large dam, Sauce Grande River, Argentina

Casado, Ana; Peiry, Jean‐Luc; Campo, Alicia María

doi:10.1016/j.geomorph.2016.05.036

Cited by 33 publications

(21 citation statements)

References 53 publications

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“…This results in a smaller, more stable channel, accommodated within the larger predam channel—a process termed accommodation adjustment (Gramms & Schmidt, ; Petts, ). These post dam river channel changes often result in impaired ecological character (Petts, ; Shafroth, Perry, Rose, & Braatne, ; Casado, Peiry, & Campo, ).…”

Section: Introductionmentioning

confidence: 99%

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

Rose

Erskine

Miners

2019

River Research & Apps

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The construction of dams significantly alters flow and sediment regimes with subsequent deleterious effects on the morphological and ecological character of rivers.Effective experimental floods can ameliorate the downstream geomorphic impacts of dams. The traditional view is that large floods are required to perform effective geomorphic work, and the geomorphic outcomes of small floods are often overlooked. Many river restoration frameworks do not consider small floods. Yet, there is evidence that the hydrological characteristics that ameliorate specific geomorphic impacts in a river are unique to each river, and a customised approach to setting the right mix of floods (including small experimental floods) is needed. In this study, we modify an existing flood effectiveness model developed for large floods, for determining the geomorphic effectiveness of small floods in a highly regulated Australian river. Two flood classes were added to the model (medium peak stream power and moderate total energy expenditure), and the flood power characteristics were rescaled to reflect the relative difference in the magnitude of the small floods and the magnitude of the geomorphic work performed. Using a step-wise approach, this customised model determined the geomorphic effectiveness of small floods.The best flood for ameliorating the geomorphic impacts of flow regulation had medium to long duration (10 to 51 days), high peak unit stream power (77 to 123 Wm −2 ) and moderate to large total energy expenditure (78,600 to 342,320 × 10 3 J). This approach to determining flood effectiveness for small floods is applicable to other geomorphically impacted river channels downstream of dams and can be used to inform experimental flood releases for geomorphic outcomes.

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Section: Introductionmentioning

confidence: 99%

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

Rose

Erskine

Miners

2019

River Research & Apps

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“…En este escenario los suelos se muestran más permeables y resistentes a la erosión, afectando a la dinámica sedimentaria e hidrológica a escala de cuenca (Gallart y Llorens, 2004;Piégay et al, 2004;Beguería et al, 2006;. La reducción de la escorrentía superficial reduce la conectividad de las laderas con los cauces, apareciendo depósitos de sedimentos fluviales que se estabilizan y revegetan (Sandercock y Hooke, 2011;Casado et al, 2016), mientras que los cauces activos se estrechan y excavan el lecho fluvial (Simon y Darby, 2002).…”

Section: Introductionunclassified

Presión antrópica sobre cuencas de drenaje en ecosistemas frágiles: variaciones en las existencias (stock) de carbono orgánico asociadas a cambios morfológicos fluviales

Halifa-Marín

Pérez‐Cutillas

Almagro

et al. 2019

CIG

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Anthropic changes in the drainage area of catchments can influence dominant erosion processes and sediment sources and mobilize specific carbon pools. It also causes changes in the sedimentary dynamics and thus in the fluvial morphology. At the same time fluvial morphologies can create the conditions for stabilizing organic carbon (OC) in sediments by burial, carbon preservation, slowing down mineralization processes, and terrestrial or aquatic plant colonization. All this might have a significant impact on the fluvial carbon sink or sources. This work explores the impact of changes in the drainage area (reforestation, check-dam building, agricultural abandonment) on fluvial morphology and on the sedimentary carbon sink of an arid and erodible catchment. The methodological approach combines cartographic analysis of land use, geomorphological photointerpretation of the channel and slope-channel connections in 1956 and 2016. Furthermore, soil and sediment sampling across the catchment for organic carbon stock determination was carried out. The watershed underwent a drastic transformation of land use from 1956, changing from an agrarian scenario to a forest pattern in 2016. This evolution altered sedimentological dynamics and fluvial morphologies. The active channel was narrowed (52%) whereas bank erosion (77%) and the adjacent gullies (11%) increased. The inner alluvial plain increased up to 31% and alluvial fans up to 37%. In addition, vegetation in the channel increased up to 16%. All this led to an increase of the total OC pool of fluvial sediments (12%), slightly above than the increase of OC total pool in the soils of the catchment (10%). The ratio of the OC stock sediments/soils was > 0.8, which indicates the large capacity of carbon sequestration of fluvial sediments, with OC stocks larger than those of agricultural soils. It was found that the geomorphological dynamics plays an important role in the OC fluvial flows. In scenarios of channel narrowing and vegetation encroachment of fluvial morphologies, the sediments can stabilize and generate OC sinks. These processes of OC sequestration in dry and ephemeral channels can have a large relevance for various ecosystem services and should be considered in the management of fluvial sedimentary areas.

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“…However, this state is disrupted owing to changes in flow and sediment conditions after a dam begins operation. A series of adjustments are needed in downstream river channels to achieve a new equilibrium relationship between channel morphology and the altered flow and sediment conditions (Petts and Gurnell, 2005;Ma et al, 2012;Vadnais et al, 2012;Casado et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Distribution of erosion intensity in the Jingjiang reach influenced by the Three Gorges Dam

Han

Sun

2018

Earth Surf Processes Landf

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Elucidation of the fluvial processes influenced by dams provides better understanding of river protection and basin management. However, less attention has been given to the erosion intensity distribution of riverbeds and its association with channel morphology and hydrological conditions. Based on hydrological and topographic data, the spatial and temporal distributions of erosion intensity (2002–2014) influenced by the Three Gorges Dam (TGD) were analyzed for the Jingjiang reach of the Yangtze River. The mechanisms underlying the distribution of erosion intensity in response to hydrological conditions were investigated. The results are as follows: (1) The erosion intensities of different discharges were not uniform, and moderate flow (10 000–27 000 m3/s) produced the largest erosion magnitude among all flow ranges. Owing to the hydrological changes caused by flood reduction and prolongation of moderate flow duration after the TGD began operating, up to 70% of the erosion amount was caused by moderate flows. (2) The lateral distribution of erosion intensity was extremely uneven, as the proportion of cumulative erosion of the low‐flow channel within the bankfull channel reached 88% in 2013. This caused the channel to become narrower and deeper. (3) The longitudinal distribution of erosion intensity was inhomogeneous. The erosion intensity in the wide reaches was greater than that in the narrow reaches, leading to smaller differences in channel morphology along the river. (4) Changes in hydrological conditions influenced by the TGD, significant reduction of sediment concentration along with flood abatement, and increased duration of moderate flow discharges were the main factors affecting erosion distribution in the post‐dam period. Our conclusions can be applied to the Yangtze River as a basis for riverbed change estimations, and river management strategies. Copyright © 2018 John Wiley & Sons, Ltd.

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Geomorphic and vegetation changes in a meandering dryland river regulated by a large dam, Sauce Grande River, Argentina

Cited by 33 publications

References 53 publications

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

Presión antrópica sobre cuencas de drenaje en ecosistemas frágiles: variaciones en las existencias (stock) de carbono orgánico asociadas a cambios morfológicos fluviales

Distribution of erosion intensity in the Jingjiang reach influenced by the Three Gorges Dam

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