# Documentation of Reused Data

**Dataset Name:** Daily discharge timeseries for the Lower Oder River system
**Version:** 1.0
**Description**: Daily discharge time series from hydrological monitoring stations along the Lower Oder River and its major tributaries (Nysa or Lusatian Neisse, and Warta Rivers). 
Data originate from a database initially compiled in the the Global Runoff Data Centre (GRDC), in turn feeding from national hydrological services 
(Bundesanstalt für Gewässerkunde (BfG) for the stations on the German-side, and Instytut Meteorologii i Gospodarki Wodnej (IMGW) for the stations on the Polish side). 
This dataset is subset to include only stations located in the lower part of the river network (kms ≥ 500) to match the spatial domain of the Lower Oder River analyses.

## 1\. Source Information

**Original Sources:** Global Runoff Data Centre (GRDC); Federal Institute of Hydrology (BAfG), Germany; Institute of Meteorology and Water Management (IMGW), Poland.

**URL/DOI:** 
GRDC: https://portal.grdc.bafg.de
IMGW: https://danepubliczne.imgw.pl/
BfG: https://www.pegelonline.wsv.de/webservices/files/ 

**Citation:**
GRDC: The Global Runoff Data Centre, 56068 Koblenz, Germany
IMGW: Institute of Meteorology and Water Management - National Research Institute || Instytut Meteorologii i Gospodarki Wodnej – Państwowy Instytut Badawczy (IMGW-PIB)


## 2\. Data Collection Details

**Collection Method:** Daily discharge observations from hydrometric stations operated by national hydrological services, compiled by the GRDC. Measurements follow national hydrological monitoring standards and reporting protocols.

**Geographic Location:** Oder River basin across Czechia, Poland, and Germany. Only stations at or downstream of river kilometer 500 are included in the Lower Oder subset.

**Temporal Coverage:** Differing length. For sites within the GRDC database, timeseries go back as early as 1949, and reach as late as 2021. This is indicated under 'dataFrom' and 'dataTo' columns.
Records were extended by downloading the most recent data from the corresponding source, to match current dynamics with accounts of long-term variability.
Further stations with very recent data (> 2017) within the Polish monitoring program were included only to account for short-term dynamics.

## 3\. Data Structure

**Data Type:** Quantitative

**Format:** CSV

**File Structure:** `Each row corresponds to one station–day observation. Columns include:
siteID (original station name)
oder_km (river kilometer of the station along the Oder longitudinal reference, based on an OpenStreetMap-based vector delineation of the river network)
ntwrk_pos (network position; typically "1_main")
River (river or waterway name)
month (numeric month)
season (meteorological season)
date (date of observation)
Discharge_m3s (daily discharge in m³ s⁻¹)
dataFrom (start date of the reporting series for each station record)`

## 4\. Access and Use Conditions

**License:** Open data with attribution requirements under GRDC/BAfG/IMGW data policy.

**Restrictions:** Users must cite the GRDC and the national hydrological agencies (BAfG, IMGW) when reusing these data.

## 5\. Data Quality and Validation

**Quality Assurance Procedures:**

Data imported as provided by GRDC and national agencies; metadata was checked for consistency in location and reporting period.
Further continuity assessments were carried out to identify and avoid artificial shifts in the timeseries, especially when switching source.

**Known Issues:**

Interpolation or reconstruction periods may exist for some stations, depending on national reporting practices, that were not indicated in the queried databases.

## 6\. Contact Information

**Dataset Curator:**
Paula Torre Zaffaroni Department of Ecohydrology and Biogeochemistry Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany paula.torre.zaffaroni@igb-berlin.de

## 7\. Data Provenance

**Transformations and Analyses:** Standardisation of column names and temporal fields across sources; addition of meteorological season and monthly identifiers.

**Record of Changes:**
v1.0 (2025-11-03): Initial extraction and harmonisation performed for external analysis.

## 8\. Additional Notes
When reusing the data, please cite the sources of the original databases. 