Estimating bankfull discharge and depth in ungauged estuaries

Gisen, Jacqueline Isabella Anak; Savenije, H. H. G.

doi:10.1002/2014wr016227

Cited by 39 publications

(48 citation statements)

References 37 publications

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“…The general finding that width increases with tidal prism and with discharge is in agreement with studies in other environments such as rivers, deltas and tidal creeks (Lacey, ; Leopold and Maddock, ; Langbein, ; Hey and Thorne, ; Savenije, ; Sassi et al., ; Gisen and Savenije, ; Lanzoni and D'Alpaos, ). However, deviations from ideal estuaries (Langbein, ; Gisen and Savenije, ) or rivers (Lacey, ; Leopold and Maddock, ; Hey and Thorne, ; Savenije, ) are present: (i) no significant relations were found between estuary depth and tidal prism, which shows in the wider scatter in supplementary Figure A.12b than in Figure a; (ii) non‐ideal estuaries are generally wider and have larger cross‐sectional areas than rivers and ideal estuaries under equal discharge (supplementary Figure A.12b), because their width is typically equal to the sum of the ideal width and the excess width, which is determined by the antecedent topography that was present before Holocene transgression.…”

Section: Resultssupporting

confidence: 90%

“…The along‐channel variation is of the same magnitude as the scatter in the dataset and illustrates that a certain width may be found with different tidal prisms, depending on the amount of excess width at that location. The exponential fits for these three cases are similar to the relations proposed by Langbein () for ideal estuaries and Gisen and Savenije (), who predicted channel width based on the upstream bankfull river discharge and a typical estuary convergence length.…”

Section: Resultssupporting

confidence: 83%

“…Many relations were proposed in the past for hydraulic geometry of rivers and tidal systems (Lacey, ; Leopold and Maddock, ; Langbein, ; Hey and Thorne, ; Savenije, ; Sassi et al. , ; Gisen and Savenije, ) (supplementary Table B.2). However, there are two issues in applying these relations to tidal systems.…”

Section: Resultsmentioning

confidence: 99%

“…Previously, relations were derived for specific tidal systems (Sassi et al. , ; Gisen and Savenije, ; Lanzoni and D'Alpaos, ) and as a function of independent, external boundary conditions, in particular river discharge, tidal amplitude and estuary mouth dimensions (Davies and Woodroffe, ; Townend, ). For rivers, it was shown that channel forming or bankfull discharge is an appropriate indicator to predict channel width (Lacey, ; Leopold and Maddock, ; Hey and Thorne, ; Savenije, ; Kleinhans and van den Berg, ).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Topographic forcing of tidal sandbar patterns for irregular estuary planforms

Leuven

Haas

Braat

et al. 2017

Earth Surf Processes Landf

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Estuaries typically show converging planforms from the sea into the land. Nevertheless, their planform is rarely perfectly exponential and often shows curvature and the presence of embayments. Here we test the degree to which the shapes and dimensions of tidal sandbars depend on estuary planform. We assembled a dataset with 35 estuary planforms and properties of 190 tidal bars to induce broad-brush but significant empirical relations between channel planform, hydraulic geometry and bar pattern, and tested a linear stability theory for bar pattern. We found that the location where bars form is largely controlled by the excess width of a channel, which is calculated as the observed channel width minus the width of an ideal exponentially widening estuary. In general, the summed width of bars approximates the excess width as measured in the along-channel variation of three estuaries for which bathymetry was available as well as for the local measurements in the 35 investigated estuaries. Bar dimensions can be predicted by either the channel width or the tidal prism, because channel width also strongly depends on local tidal prism. Also braiding index was predicted within a factor of 2 from excess width divided by the predicted bar width. Our results imply that estuary planform shape, including mudflats and saltmarsh as well as bar pattern, depend on inherited Holocene topography and lithology and that eventually convergent channels will form if sufficient sediment is available.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Topographic forcing of tidal sandbar patterns for irregular estuary planforms

Leuven

Haas

Braat

et al. 2017

Earth Surf Processes Landf

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“…O 'Brien, 1969;Eysink, 1990;Friedrichs, 1995;Lanzoni and D'Alpaos, 2015;Gisen and Savenije, 2015;Leuven et al, 2017).…”

mentioning

confidence: 99%

Morphology of bar-built estuaries: relation between planform shape and depth distribution

Leuven

Selaković

Kleinhans

2018

Preprint

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Abstract. Fluvial-tidal transitions in estuaries are used as major shipping fairways and are characterised by complex bar and channel patterns with a large biodiversity. Habitat suitability assessment and study of interactions between morphology and ecology therefore require bathymetric data. While imagery offers data of planform estuary dimensions, only for a few natural estuaries bathymetries are available. Here we study the relation between along-channel planform geometry, obtained as the outline from imagery, and hypsometry, which characterises the distribution of along-channel and cross-channel bed-levels. 5We fitted the original function of Strahler (1952) to bathymetric data along four natural estuaries. Comparison to planform estuary shape shows that hypsometry is concave at narrow sections with large channels, while complex bar morphology results in more convex hypsometry. We found a relation between hypsometric function shape and the degree to which the estuary width deviates from an ideal convergent estuary, which is calculated from river width and mouth width. This implies that the occurring bed level distributions depend on inherited Holocene topography and lithology. Our new empirical function 10 predicts hypsometry and along-channel variation in intertidal and subtidal width. Combination with the tidal amplitude allows an estimate of inundation duration. A validation of the results on available bathymetry shows that predictions of intertidal and subtidal area are accurate within a factor 2 for estuaries of different size and character. Locations with major human influence deviate from the general trends, because dredging, dumping, land reclamation and other engineering measures cause local deviations from the expected bed-level distributions. The bathymetry predictor can be used to characterise and predict 15 estuarine subtidal and intertidal morphology in data-poor environments.

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Estimating river discharge using multiple‐tide gauges distributed along a channel

2016

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Reliable estimation of freshwater inflow to the ocean from large tidal rivers is vital for water resources management and climate analyses. Discharge gauging stations are typically located beyond the tidal intrusion reach, such that inputs and losses occurring closer to the ocean are not included. Here, we develop a method of estimating river discharge using multiple gauges and time‐dependent tidal statistics determined via wavelet analysis. The Multiple‐gauge Tidal Discharge Estimate (MTDE) method is developed using data from the Columbia River and Fraser River estuaries and calibrated against river discharge. Next, we evaluate the general applicability of MTDE by testing an idealized two‐dimensional numerical model, with a convergent cross‐sectional profile, for eighty‐one cases in which nondimensional numbers for friction, river flow, and convergence length scale are varied. The simulations suggest that MTDE is applicable to a variety of tidal systems. Model results and data analyses together suggest that MTDE works best with at least three gauges: a reference station near the river mouth, and two upstream gauges that respond strongly to distinct portions of the observed range of flow. The balance between tidal damping and amplifying factors determines the favorable location of the gauges. Compared to previous studies, the MTDE method improves the time resolution of estimates (from 2.5 to <1 week) and is applicable to systems with mixed diurnal/semidiurnal tides. However, model results suggest that tide‐induced residual flows such as the Stokes drift may still affect the accuracy of MTDE at seaward locations during periods of low river discharge.

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Estimating bankfull discharge and depth in ungauged estuaries

Cited by 39 publications

References 37 publications

Topographic forcing of tidal sandbar patterns for irregular estuary planforms

Topographic forcing of tidal sandbar patterns for irregular estuary planforms

Morphology of bar-built estuaries: relation between planform shape and depth distribution

Estimating river discharge using multiple‐tide gauges distributed along a channel

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