Knowledge base

Standards, water status assessment, indices - made approachable

Reference articles for people running monitoring and reading water assessments: how to understand classes, ecological and chemical status, assessment elements and regulations.

Ammonia in water: NH₃ or NH₄⁺ - why the form decides toxicity

A laboratory reports ammonium nitrogen (TAN), but for fish and other aquatic organisms only un-ionised ammonia (NH₃) is toxic. Its share depends on pH and temperature - find out when a result is safe.
Algae and blooms in a pond - how to deal with them

A pond turning green is usually the result of an excess of nutrients and sun. What drives algae, which methods really help and what to avoid.
A cyanobacterial bloom - what to do and how to prevent it

A cyanobacterial bloom is a threat to health and the ecosystem. How to recognise a bloom, what to do in the moment (bathing site, pond) and how to reduce the risk in the long term.
Fish kills - causes and what to do

A mass fish kill usually has several possible causes. How to recognise them, what to do first and whom to report it to - a practical guide for those who care for waters.
Self-purification of waters - how a river copes on its own

Waters have a natural capacity for self-purification. What physical, chemical and biological processes lie behind it, what they depend on and why they have their limits.
A water-law permit and report - the basics

Using water often requires water-law consent. What a water-law permit is, what the water-law report is for and when an obligation to monitor comes into play.
Statistics in monitoring - detecting trends and correlations

How to reliably judge whether there is a trend in the data and whether indicators are linked. Basic methods for environmental data: a trend test, correlations and common pitfalls.
Converting concentration units in water analysis (mg/l, µg/l, mol/l)

mg/l, µg/l, mol/l, ppm, forms of nitrogen and phosphorus - concentration units can be a source of mistakes. How to convert them and what to watch for when comparing results from different sources.
Water monitoring in Poland (PMŚ) - surveillance, operational, investigative

The State Environmental Monitoring divides water studies into several types with different aims. How surveillance, operational and investigative monitoring differ and who runs them.
The Water Framework Directive - aims and principles in a nutshell

The WFD is the foundation on which water assessment and protection in the EU rests. What aims it sets, what principles it works by and why everything revolves around water bodies.
Water hardness - units and conversions

Water hardness is given in German degrees, mg CaCO3 per litre, mmol/l and meq/l. What hardness means, how to convert between units and how to read the result.
The macrophyte index (MIR, ESMI) - how aquatic vegetation is assessed

MIR for rivers and ESMI for lakes turn the composition and abundance of aquatic plants into a status assessment. How these macrophyte indices work and what makes up the result.
Carlson's TSI index - how to assess trophic status with a number

Carlson's TSI turns transparency, chlorophyll and phosphorus into a single number describing a lake's fertility. How to calculate it, how to read the scale and what to watch for in interpretation.
BMWP-PL - how to calculate the macroinvertebrate biotic index

BMWP-PL turns a list of macroinvertebrates into a number describing water quality. How the family scoring works, how to calculate BMWP and ASPT, and how to read the result.
The nitrogen and phosphorus cycle in waters - where nutrients come from

Nitrogen and phosphorus drive eutrophication. Where they come from in waters, in what forms they occur and why limiting them is the key to protecting lakes and rivers.
BOD, COD, TOC - indicators of organic matter in water

BOD, COD and TOC describe the content of organic matter and the demand for oxygen. How they differ, what they mean and why together they tell you about a water's loading.
Benthos, plankton, macrophytes - who's who in an aquatic ecosystem

Plankton, benthos, periphyton, macrophytes, nekton - a short, accessible guide to the groups of aquatic organisms and their role in water-quality indicators.
Reference values and background - what to compare results with

The same value can be typical for one water and alarming for another. What reference conditions and geochemical background are and why every water has its own reference value.
Unusual water indicator values - what they can mean

High conductivity, low oxygen, high phosphorus, sudden turbidity - what lies behind unusual readings. An overview of the most common causes of deviations in water-quality indicators.
How to interpret water test results

A number from a water test says little on its own. How to read it: against the standard, the background and the trend, taking context into account - a practical guide to interpreting results.
QA/QC in monitoring - how to ensure data reliability

Data is worth only as much as the trust in it. What QA/QC in monitoring is, how calibration, blanks, duplicates and measurement uncertainty protect the quality of results.
A water-monitoring report - what it should contain

A good report turns data into conclusions. What elements a water-monitoring report should have - from the aim and methodology, through results and assessment, to conclusions and recommendations.
A sampling plan and monitoring programme - how to design it

Good monitoring begins with a plan. How to set the aims, points, frequency and range of indicators so that the data is representative, comparable and useful.
How to prepare data for statistical analysis (R, STATISTICA)

Most of the time in analysis is eaten up by tidying data. How to arrange measurements so they load easily into R, STATISTICA or Python - format, units, missing data and values below the threshold.
Time-series analysis in monitoring - trends, seasonality, anomalies

A single measurement says little - the value is in the series. How to read monitoring time series: recognising trend, seasonality and anomalies, and avoiding common interpretation mistakes.
Exporting measurement data to Excel - good practice

Well-exported data is the basis of analysis. How to organise measurements for Excel, which pitfalls to avoid (dates, units, separators) and how the long format differs from the wide one.
Open environmental data - which sources are worth knowing

Weather, hydrology, air and water quality, maps - much environmental data in Poland is public and free. An overview of the most important sources and what you will find in them.
Telemetry and online sensors in monitoring - automatic data recording

Online sensors and telemetry change monitoring: the data flows in by itself, without field visits. How continuous measurement works, what benefits it brings and what to keep in mind when running it.
How to combine your own measurements with public data (weather, hydrology)

Many environmental measurements only make sense set against weather and hydrology. Why it is worth combining your own data with public sources and how to do it without the tedious stitching of spreadsheets.
GIOŚ data - air and water quality from state monitoring

GIOŚ runs the State Environmental Monitoring and publishes data on air and water quality. Where to find it, what it contains and how to use it as a reference for your own measurements.
IMGW-PIB data - how to download and use it in water monitoring

IMGW-PIB makes meteorological and hydrological data publicly available. How to download it, what it contains and how to use rainfall, temperature or water levels as context for your own measurements.
Environmental quality standards (EQS) and priority substances - the chemical status of waters

The chemical status of waters is assessed against environmental quality standards for priority substances. What EQS and priority substances are and how they differ from specific pollutants.
Ecological potential - assessing heavily modified and artificial waters

Not every water body is assessed like a natural river. What heavily modified and artificial waters are, why their ecological potential is assessed instead of status and what its scale looks like.
Water bodies (JCWP) - what they are and how to find yours

A water body (JCWP) is the basic unit of assessment and management of waters under the Water Framework Directive. What it means, what types of water bodies there are and where to check the one that concerns you.
Eutrophication and trophic status - how the fertility of waters is assessed

Eutrophication is the enrichment of water with nutrients and one of the main problems of lakes. What trophic status is, which indicators describe it and how it relates to the assessment of water status.
Elements of ecological status assessment - biological, physico-chemical, hydromorphological

Ecological status is made up of three groups of elements. Which biological, physico-chemical and hydromorphological indicators decide the class and why biology is decisive.
Ecological vs chemical status of waters - what the difference is

Ecological and chemical status are two separate assessments of surface waters. How they differ, why they are assessed separately and how they combine into the overall status of a water body.
Classes and status of surface water quality - how to read them

Water status is assessed in a single system stemming from the Water Framework Directive. How to understand the classes of ecological status, chemical status and the overall assessment of water bodies (JCWP).
Verifying measuring devices - method comparison

How to check whether a new sensor or online probe agrees with a reference method. Deming regression, Bland-Altman plot, bias and limits of agreement - in plain terms.