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The method based on original metric called Hydromorphological Index for Rivers (HIR) was developed in 2017 for the purpose of the monitoring of the hydromorphological status of flowing waters in Poland. It fulfils the requirements of the EU Water Framework Directive (WFD). It allows the assessment of both lowland rivers as well as mid-altitude and highland streams. The proposed system can be used to assess the natural and heavily modified rivers as well as artificial channels. The basis of the proposed system is a field survey, which is supplemented by the analysis of Geographic Information Systems (GIS) data and remote sensing materials. The analysis of the GIS data and remote sensing materials already enable to estimate preliminary classification of the hydromorphological status of the non-surveyed water bodies. On the basis of the field survey, the principal HIR value can be estimated for the considered river site and comparing with the reference conditions, the hydromorphological quality status in the five-class system can be calculated. The properly selected, representative survey sites (one or more depending on the heterogeneity of the environment), enable the classification and evaluation of entire surface water bodies in the framework of the national environmental monitoring. The GIS component of the HIR proved to be useful in verifying the determination of heavily modified water bodies and in assessing the needs of river restoration. It was also applied in the development of the National river restoration program for predicting the impact of the proposed restoration measure on the state of hydromorphology.

The Macrophyte Index for Rivers (MIR) was developed in 2007, and it was one of the first biological methods developed in Poland under the requirements of the Water Framework Directive to assess the ecological status of running waters. It is based on the quantitative and qualitative evaluation of 153 indicator taxa. The aim of this study was to evaluate the ability of the MIR method to detect trophic degradation in rivers and to compare its efficiency with other macrophyte metrics. Our investigation was based on 100 sites, representing a very clear gradient from near oligotrophic to eutrophic conditions. The results showed that macrophytes can be distinguished in terms of their ecological requirements for nutrient concentration in water, and this can be used to develop an effective system of freshwater assessment. The MIR was shown to be the indicator most strongly correlated with various forms of nutrients, and it was demonstrated that calibration of the macrophyte method to local biogeographical conditions resulted in greater effectiveness of the assessment method.

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The variation of a number of parameters characterizing aquatic plant assemblages in rivers across a wide trophic gradient was investigated to evaluate their usefulness for a Polish national river monitoring system. Analyses were conducted at 100 sites included in the national river monitoring system, representing a uniform river type, i.e., small- and medium-sized lowland rivers with a sandy substrate. Results of botanical surveys, which were supplemented with comprehensive monthly quality records, were obtained from the national monitoring database. By analyzing the Jaccard distances of the botanical metrics using the adonis function, the variation in species composition between rivers of different trophic status was determined. The group consisting of the most degraded rivers was the most homogeneous in terms of botanical composition. The cleanest rivers displayed a high level of heterogeneity within their group, as numerous different unique species were found there at low frequencies. The variation of the macrophyte metrics used to assess the ecological status (Macrophyte Index for Rivers (MIR) and River Macrophyte Nutrient Index (RMNI)) reflected a trophic gradient. We confirmed that vegetation diversification along a trophic gradient is evident enough to detect degradation in a five quality class system.