Hydrology, sediment transport and erosion in Longyeardalen (Research in Svalbard RiS ID 11641)

This is a long term monitoring program performed at The University Centre in Svalbard (UNIS) in collaboration with Geological Survey of Norway (NGU), Longyearbyen Lokalstyre and the Norwegian Water and Energy Directorate (NVE).

The monitoring was initiated in 2018 and continues to run thanks to support of UNIS BSc course (AG221) and MSc program

The project includes:

1. Hydrological monitoring of Longyearelva 

2. Investigation of suspended sediment and bedload transport in Longyearelva

3. Investigation of riverbed erosion

4. Identification and monitoring of geohazards in Longyeardalen

5. Investigation of erosion in Longyeardalen

6. Creation of 3D models (DEM) of Longyearelva as well as Larsbreen and Longyearbreen margins, moraines and their forefields 

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Hydrological monitoring

A monitoring station is established every melt season since 2018 at the bridge on the north side of Longyearelva by the entrance to the fjord (see picture to the right)

The station consists of a data logger recording hourly values of water level in Longyearelva from the very beginning of snowmelt in June until the freez-up in October.

In addition to freshwater discharge, water quality is monitored by hourly recordings of electrical conductivity.

 

In the picture to the left two UNIS and NTNU MSc students Lene Pallesen and Marthe Ottem are getting ready to set up the monitoring station in June 2021. They will be responsible for maitanance and data collection throughout the summer as part of their Msc thesis projects 

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Monitoring of suspended sediment transport and bedload transport

To know how much fine suspended sediments is being moved every summer by Longyearelva, water samples are being taken four times a day with the use of the automatic pump sampler

After collection, the water is filtered and sediment dried and weighted. 

Knowing water discharge allows to quantify daily sediment fluxes from Longyeardalen as well as total sediment transport into Adventfjorden throughout the entire summer.

Lene and Marthe, MSc students, installing pressure transducer measuring water level

June 2021

Red rocks are placed in the river to monitor bedload transport

The rocks are sorted according to size and every row consist of a different size of rocks.

The biggest rocks are usually placed up stream while the smallest downstream

During the summer water will move the rocks, which ones and how much will depend on the river discharge

At the end of the summer the movement of rocks will be measured and erosive power of the river will be estimated.