River inputs are of importance to the evaluation of the environment in the North Sea. Rivers convey freshwater, sediment and nutrients to sea. A number of economically and environmentally important species migrate between freshwater and the sea at different stages of their lives; meaning that the quality of both the marine and the freshwater environment is important to their survival. The aim of the river inputs challenge was to assess the inputs from rivers flowing into the North Sea basin that could be used to evaluate the environment of the North Sea.
For each river inflow a time series covering a ten year period (2005-2015) for the following parameters was required:
- Total nitrogen
Time series data would allow annual inputs and monthly averages, maxima and minima for the ten year period to be calculated.
There were data gaps for all of the variables required for this challenge. With regards to the physio-chemical inputs the minimum, maximum and mean values were not calculated as only three of the countries with rivers inputting to the North Sea Basin held comprehensive data sets. There is also low confidence in the data that has been collected as the upper and lower annual values have been reported as the same, or similar, leading to the conclusion that these are actually averages rather than minima and maxima.
For the biological components, in this case fish species of salmon and eel, only the UK (specifically England) held comprehensive data sets that included abundance of the fish.
As with previous challenges several datasets were not fully useable due to the lack of metadata detailing location or dates of collection. Where data was not geo-referenced it was difficult to determine if it was useful for the challenge.
A main issue identified was that none of the data for the challenge was available from a centralised data portal as was the case with other challenges. Therefore national agencies within those countries with river inputs to the North Sea were contacted which was time consuming and occasionally incurred a data handling charge.
With regards to understanding the general river inputs to the North Sea basin from a geographical perspective i.e. where are they coming from, the challenge was met. However, due to variations in the level of geo-referencing associated with the data, it was not possible to provide a fully geo-referenced spatial presentation of the data. Understanding the inputs over time was not fully met for all countries where rivers input to the North Sea as for most there are only 3 years of data available for use in the challenge.
The data gathered for this challenge was not provided by EMODNet as it was all deemed to be riverine in nature regardless of the fact the rivers flow into a marine area. It would seem that data for transitional waters are not held centrally by EMODNet which has made conducting the challenge difficult. It would therefore be useful if either EMODNet held this data or the issues associated with the data from the European Environment Agency (EEA) i.e. sediment discharges and the Waterbase datasets, were addressed and a link to these placed on the EMODNet home page.
Full information on the data gathered, the adequacy of the information, and the issues identified is presented the Final Project Report.