DEL107 – 11201882 Dune dynamics and preservation in the River Waal, using Multibeam and Parametric Echo Sounding (PES) [Acronym: PES-Waal]

Aanleiding van het project

Dune dynamics and preservation in the River Waal, using multibeam (MBES) and parametric echo sounding (PES).
River dunes are common in most low-land rivers in the world, including the Dutch rivers (Fig. 1), and play a central role in sediment transport and deposition processes (Kleinhans, 2001, Best, 2005). The variability in dune height and dynamics depends on parameters such as discharge (Julien and Klaassen, 1995, Wilbers and Ten Brinke, 2003, Cisneros et al., 2019) and determines the navigability of rivers (e.g. Amsler and Garcia, 1997; www.covadem.org).
Figure 1: Bathymetric map, showing bedforms in the Waal near Waardenburg.
Although river dunes have been studied extensively (e.g. Kleinhans, 2002, Best, 2005, and references therein, Cisneros et al., 2019), and although net sediment budgets due to downstream migrating dunes can be estimated from dune tracking (Wilbers and Ten Brinke, 2003), net volumes as calculated from the net changes in bed level in MBES time series do not fully explain the bedload sediment fluxes in rivers, nor how much sediment is being stored (preserved) in the river bed or what time scales are involved.
Dune preservation is crucial in the understanding of the spatial and temporal variations in sediment transport and deposition rates in rivers (i.e. KIA and NKWK questions) and can be studied from internal dune structures (Paola and Borgman, 1991, Leclair and Bridge, 2001, Reesink et al., 2015, Van de Lageweg et al., 2016). Using the high-resolution acoustic technique Parametric Echo Sounder (PES), we may observe the internal structures and reactivation (erosion) surfaces of bedforms in the subsurface of river beds (Sambrook Smith et al., 2013; and Fig. 2: unpublished data by courtesy of J. Best).
Figure 2: Example of sub-bottom PES data of internal structures of bedforms and reactivation surfaces in the Mekong river, Cambodia. For scale: one block in the grid is 10 m horizontally and 1 m vertically (Figure remains copyright of Jim B

Doel van het project

The aim of this project is to generate new fundamental knowledge on the spatial and temporal variations in the preservation and reactivation of river dunes in the subsurface of the river Waal. The time scales that are involved will follow from this research. This project will contribute to the understanding of sediment transport and deposition processes in rivers and the long-term behaviour of rivers.
Hereto, the main project objectives are:
– to research the applicability of innovative geophysical techniques in two field surveys in time, in which we combine high-resolution parametric echo sounding (PES) data with simultaneous multibeam echo sounding (MBES, preferably bathymetric and backscatter) data and sediment cores (cores only with the second survey) for future linking of internal dune structures to their morphodynamics and sediment characteristics.
– to analyse the PES data
– to establish dune preservation and reactivation from observed internal structures of each of the PES-surveys and in the period between the two surveys
Since, to our knowledge, this is the first time that PES will be conducted in Dutch rivers, we will test the performance of PES in three different parts of the Waal with varying grain sizes (e.g. gravel/sand/finer sediments), but more importantly, the three sites are selected to investigate the role of grain-size distribution in flow and bed dynamics upstream and downstream. Furthermore, we will conduct two PES surveys in time, in order to estimate what temporal scales play a role in the dune dynamics and their preserved internal structures.
The PES survey sites and timing will be attuned to the ongoing multibeam monitoring, so that the new datasets flawlessly fit in the longer time series, and will be co-ordinated by Van den Herik and Rijkswaterstaat. The sub-bottom PES data will be accompanied by vibrocoring for geological verification and grain size analyses in the lab. Coring locations and timing will again have to be attuned with

Omschrijving van de activiteiten

Work package 1: design of PES surveys, acquisition of PES and MBES data and coring:
(Dec 2019 – Nov 2020)
– to assemble existing data: complete bi-weekly, high-resolution MBES time series of the Waal that we already have available for 2005-2015 between Slijk-Ewijk and Ochten, previous grain size data, hydrodynamic data from Rijkswaterstaat, and geological data of the Waal (e.g. TNO’s DINO-database),
– to preliminary analyse selected multibeam datasets of the bi-weekly time series for the purpose of designing the PES surveys
– to design the PES surveys (sites, estimate of period between two PES surveys, route, speed, etc)
– to conduct the field surveys; these are planned early in the project and to fit into the ongoing MBES monitoring.
– to collect 18 vibrocores with the 2nd PES survey, based on the preliminary observations of the 1st PES survey to plan locations
Work package 2: data analyses:
(Mar 2020 – Mar 2021)
– preliminary analysis of river dune dynamics of selected MBES bathymetry time series. (budget limit constrains us to processing the newly acquired MBES bathymetry data in WP1 and a small number of existing datasets)
– analysis of PES data acquired in WP 1
– if MBES backscatter was successfully acquired in WP1, processing the backscatter data
Work Package 3: interpretation of results:
(Sep2020 – Dec 2021)
– to interpret sedimentary structures in the shallow subsurface and establish dune preservation and reactivation from observed internal structures of each of the PES-surveys and in the period between the two surveys
– if MBES backscatter was successfully acquired in WP1, river bed sediment classification of backscatter data
(The coupling dune preservation from PES data to dune morphodynamics from the bi-weekly MBES time series is future research, intended in ‘TKI phase 2’ to be applied for in 2020.)
Work Package 4: reporting and dissemination:
(Mar 2021 – Dec 2021)
– writing up final project report
– abstract, presenting

Verwachte resultaten

Volgnr Wat Wanneer (jaar)
1
survey design (incl. PES, MBES and vibrocoring)
2019 and prior to each survey in 2020
2
New data from surveys in the Waal:
– 2 PES datasets in time (new in the world)
– 2 MBES bathymetry datasets (and MBES backscatter if possible)
– 18 sediment cores (Note that the descriptions and grain size analyses are planned in “Phase 2”, still in 2020)
2020
3
New knowledge:
a. new insights in the preservation and reactivation of dunes from PES data
b. time scale of temporal variations in erosion, sediment transport and deposition at 3 sites in the Waal,
c. the role of grain size in dune dynamics
2020 & 2021
4
Dissemination of results:
a. project website
b. progress reports online
c. if a M.Sc. internship is carried out: MSc dissertation
a. 2020 (set-up <3 months after start project)
d. final project report
e. abstract and conference presentation
b. 2020-2021
c. 2020-2021
d. 2021
e. 2021

Innovativiteit

1. New technique, new knowledge and new in the Netherlands – yet proven to be successful elsewhere:
PES was never used in Dutch rivers before to investigate the preservation of river dunes. PES was applied by Prof. Best’s team in the Ríos Bermejo and Paraná, Argentina (Sambrook Smith et al., 2013, Sambrook Smith et al., 2016) and the Mekong river, Cambodia (see Fig. 2, as for yet unpubl. data of J. Best) and was demonstrated to be successful as a technique in sandy and finer sediments. If we manage to collect also multibeam backscatter data (in addition to the MBES bathymetry), then we can make a high-resolution map of bed sediment types that cannot be done with the classical (currently used) method using sampling. To date, in the NLds, shorter MBES time series were used to analyse the net bed level differences and dune tracking in order to calculate net bedload transport volumes. Dune preservation in the subsurface provides crucial insight for reconstructing true bedload transport and deposition processes and what time scales (storage times) are involved. This new approach not only means adding crucial (and, to date, missing) information for studying sediment transport in Dutch rivers, butalso provides us with a new type of data and new insights in river dune preservation and reactivation in river systems, not existing in the Netherlands so far. Hence, this project ‘imports’ this knowledge to the Netherlands in a valuable knowledge transfer through superb international collaboration with knowledge institutes, government and industry, thereby strengthening our knowledge position in Delta Technology.
2. Unique-in-the-world datasets towards 3D and an unprecedented handle on time:
The combination of morphodynamics of the bed (2-D surface), PES (looking into the subsurface) in time series and sediment cores to interpret the sub-surface data makes this approach unique in the world (not in any river was this combination of data ever acquired). This approach l

Valorisatie

Welk product (zie boven)? Product (see above) Wie gaat het gebruiken? Who will be using it? Wie gaat ervoor zorgen, en hoe? Who will be responsible for this and how will this be done?
PES survey design
– Van den Herik in this project and beyond;
– others (industry/knowledge institutes) who want to design their own surveys
– Deltares/UIUC/UU/VdH/RWS jointly plan the surveys
– PES-surveys need to be fitted in the ongoing RWS MBES monitoring (VdH, RWS)
new data (PES, MBES, core)
– UIUC, UU, Deltares in this project and beyond
– core data to go into DINO-database (public access)
VdH will conduct the survey (vessel, crew); UIUC will instruct and supervise on board; Deltares will assist on board, both technically (e.g. pole to mount PES) and scientifically; RWS will fit this project in the regular MBES surveying schedule.
new knowledge
– scientists, applied researchers, students
– managers and industry (surveyors, consultants)
all knowledge partners
interim reporting and final project report
– applied scientists, river managers and industry, students
– all partners contribute to the report;
– Deltares PI will finalise the interim and final reports
– Deltares will make reports accessible on project website (public access)
Project website
– public
– TKI team will set up the site
– all partners provide info for website
– Deltares PI is responsible for updating the website info
abstract, conference presentation
– peer researchers, conference attendees, students
– joint effort all partners
– first author will be corresponding author

Link naar projectresultaten…