INTRODUCTION<\/h2>\n
The\u00a0Water Framework Directive (WFD) (2000\/60\/EC)\u00a0[1] obliges EU Member States to assess the\u00a0hydromorphological status of\u00a0surface waters. Together with biological, chemical, and physico-chemical components, it forms part of\u00a0the\u00a0monitoring of\u00a0the\u00a0ecological status of\u00a0water bodies. The\u00a0term \u201chydromorphology\u201d includes information on geomorphological and hydrological processes occurring in\u00a0watercourses, including their longitudinal, lateral, and vertical continuity. According to the\u00a0WFD, the\u00a0assessment of\u00a0the\u00a0hydromorphology of\u00a0water bodies of\u00a0the\u00a0river category is divided into three main\u00a0elements:<\/p>\n
\n
- \n
- hydrological regime,
\n
\n<\/li>\n - watercourse continuity,
\n
\n<\/li>\n - morphological conditions.<\/li>\n<\/ol>\n
The\u00a0objective of\u00a0the\u00a0hydromorphological assessment is to determine the\u00a0extent of\u00a0anthropogenic influence on water bodies within\u00a0these elements. The\u00a0hydromorphological assessment is used in\u00a0many steps of\u00a0the\u00a0planning process under the\u00a0WFD. It plays a\u00a0role in\u00a0defining water bodies, analysing significant impacts, determining heavily modified water bodies, selecting the\u00a0location of\u00a0monitoring profiles and, last but not least, in\u00a0designing effective measures to achieve good status or potential of\u00a0a\u00a0water body, which is the\u00a0main\u00a0objective of\u00a0the\u00a0WFD. The\u00a0basic legislative document regulating the\u00a0assessment of\u00a0the\u00a0hydromorphological status of\u00a0water bodies at the\u00a0European level is the\u00a0aforementioned WFD. In\u00a0Czech legislation, this issue is regulated by Act No. 254\/2001 Coll., the\u00a0so-called Water Act, and Decree No.\u00a098\/2011\u00a0Coll., which determines the\u00a0method and scope of\u00a0the\u00a0surface water status assessment. The\u00a0correct and consistent implementation of\u00a0the\u00a0WFD in\u00a0accordance with the\u00a0European Union objectives is supported by the\u00a0methodological guidelines of\u00a0the\u00a0Common Implementation Strategy (CIS) and the\u00a0relevant standards. In\u00a0the\u00a0field of\u00a0hydromorphological assessment, these are the\u00a0standards \u010cSN EN 14614\u00a0[2] and \u010cSN\u00a0EN 15843\u00a0[3].<\/p>\n
In the Czech Republic, the hydromorphological status of water bodies is currently formally assessed using the Hydroecological Monitoring (HEM) methodology [4, 5], which has been officially accepted by the Ministry of the Environment (MoE). However, this methodology has only been used to a limited extent and the assessment data have not yet been officially reported as part of regular reports on the status of water bodies. The methodology users often pointed out its time-consuming nature, especially in collecting field data and subsequent calculations, as well as a higher degree of subjectivity in assessing individual indicators. Although the methodology meets the basic requirements of Czech and European legislation, significant progress has been made in the field of assessing the hydromorphology of watercourses since its inception, which has also been reflected in the updates of the relevant standards. This development has shown the need to revise the existing approach so that it better reflects new requirements and current knowledge. In response to these challenges, a new methodology for assessing the hydromorphological status of water bodies was developed within TA CR project No. SS05010135 \u201cDevelopment of a methodology for monitoring and assessing hydromorphological characteristics of watercourses\u201d, referred to by the acronym HYMOS \u2013 Methodology for assessing the ecological status of flowing surface water bodies (river category) using hydromorphological elements. The aim of this article is to briefly introduce this methodology and show its applicability using the example of the assessment of 15 selected water bodies in the Czech Republic.<\/p>\n
METHODOLOGY<\/h2>\n
HYMOS Methodology<\/h3>\n
General characteristics of\u00a0the\u00a0methodology<\/span><\/strong><\/span><\/p>\n
The\u00a0methodology was developed primarily for the\u00a0assessment of\u00a0flowing surface water bodies, both natural and heavily modified. However, it is not intended for the\u00a0assessment of\u00a0artificial water bodies. Considering the\u00a0need for a\u00a0flexible approach to the\u00a0assessment of\u00a0hydromorphology, it was also designed to allow the\u00a0assessment of\u00a0watercourses that are not defined as water bodies. In\u00a0developing the\u00a0methodology, emphasis was placed on the\u00a0legislative framework and standards listed in\u00a0the\u00a0introductory chapter. The\u00a0results of\u00a0the\u00a0European project REFORM (REstoring rivers FOR effective catchment Management)\u00a0[6] and the\u00a0Morphological Quality Index (MQI) methodology\u00a0[7], which was developed within\u00a0the\u00a0aforementioned project, played a\u00a0significant role in\u00a0its development. Based on new findings from the\u00a0REFORM project and the\u00a0MQI methodology, the\u00a0EN 14614 standard (2020, original version approved in\u00a02005) has been updated. The\u00a0procedure for the\u00a0identification of\u00a0significant impacts on morphology and hydrological regime\u00a0[8] was also an important starting point for the\u00a0development of\u00a0the\u00a0new methodology.<\/span><\/p>\n
Based on current requirements and recommendations, the\u00a0HYMOS methodology includes both the\u00a0assessment of\u00a0forms and processes, while monitoring processes not only in\u00a0the\u00a0assessed reach, but also above it, for example influencing sediment transport affecting the\u00a0deepening of\u00a0the\u00a0watercourse downstream. The\u00a0methodology views watercourses as dynamically changing systems that develop over time, with a\u00a0possible change from one channel planform to another. For this reason, the\u00a0methodology does not determine a\u00a0reference status based on archival maps, although archival maps serve as an important basis for identifying anthropogenic modifications in\u00a0the\u00a0past. The\u00a0full version of\u00a0the\u00a0methodology is freely available on the\u00a0official website of\u00a0the\u00a0HYMOS project (https:\/\/hymos.czechglobe.cz\/)\u00a0[9]. From the\u00a0website, the\u00a0user also has access to a\u00a0specialized database\u00a0[10], which contains morphological characteristics of\u00a0water bodies and defined reaches, as well as to a\u00a0web application and software for automating the\u00a0assessment of\u00a0hydromorphological status\u00a0[11].<\/span><\/p>\n
Reference conditions<\/span><\/strong><\/span><\/p>\n
As opposed to previous methodologies, reference conditions are not determined as specific characteristics of\u00a0individual assessed indicators for individual types of\u00a0watercourses, e.g. in\u00a0the\u00a0form of\u00a0precise values of\u00a0the\u00a0variability of\u00a0the\u00a0riverbed width or the\u00a0number of\u00a0natural substrate types. In\u00a0the\u00a0past, this approach often led to inaccuracies in\u00a0the\u00a0assessment. The\u00a0reference conditions are now defined in\u00a0accordance with the\u00a0WFD and the\u00a0findings of\u00a0the\u00a0REFORM project as follows:<\/span><\/p>\n
- \n
- for indicators expressing the\u00a0effects of\u00a0anthropogenic pressures (e.g.\u00a0bank\u00a0stabilization, channel bed modification), reference conditions are defined as the\u00a0absence of\u00a0pressures or their minimal presence, which does not have a\u00a0significant impact on fluvial processes, morphology, or\u00a0natural development of\u00a0the\u00a0channel;<\/span><\/li>\n
- for indicators expressing the\u00a0\u201cfunctionality\u201d of\u00a0a\u00a0watercourse and its response to anthropogenic pressures (e.g. bed substrate, bed elements), reference conditions are defined as the\u00a0presence of\u00a0forms and processes that are expected for a\u00a0watercourse located in\u00a0given physical-geographical conditions (e.g. valley slope and shape, intensity of\u00a0sediment input).<\/span><\/li>\n<\/ul>\n
This method of\u00a0determining reference conditions places higher expert demands on the\u00a0methodology users. In\u00a0order to facilitate the\u00a0assessment as much as possible, a\u00a0hydromorphological typology of\u00a0watercourses was created within\u00a0the\u00a0HYMOS project. It is based on a\u00a0combination of\u00a0the\u00a0following key parameters: valley slope, confinement index (the\u00a0ratio of\u00a0floodplain\u00a0width to channel width), potential input of\u00a0coarse sediments to the\u00a0river, and the\u00a0size of\u00a0a\u00a0watercourse (according to Strahler stream order). Based on these parameters, hydromorphological types of\u00a0watercourses were created, with accompanying descriptions of\u00a0characteristic morphological parameters of\u00a0the\u00a0river. These descriptions serve as a\u00a0guide for hydromorphological assessment. The\u00a0parameters entering the\u00a0typology are also used when dividing water bodies into (relatively) homogeneous reaches, which allows for a\u00a0more accurate and consistent assessment.<\/span><\/p>\n
Division of\u00a0water bodies into reaches<\/strong><\/span><\/p>\n
Water bodies defined in\u00a0the\u00a0Czech Republic often show a\u00a0high degree of\u00a0inhomogeneity. Within\u00a0a\u00a0single water body, there are usually different hydromorphological types of\u00a0watercourses, which differ in\u00a0their response to anthropogenic pressures. This definition is not fully in\u00a0line with the\u00a0WFD requirements or with the\u00a0recommendations of\u00a0the\u00a0CIS Guidelines No.\u00a03 and 10\u00a0[12,\u00a013]. Given the\u00a0requirement to maintain\u00a0the\u00a0existing definition of\u00a0water bodies, it was necessary to divide them into more homogeneous reaches for the\u00a0purposes of\u00a0assessing hydromorphological status. The\u00a0following criteria were used to define the\u00a0reaches:<\/p>\n
- \n
- hydromorphological typology parameters \u2013 valley slope and shape, potential input of\u00a0coarse sediments, and size of\u00a0the\u00a0watercourse;<\/li>\n
- channel planform \u2013 e.g. change from meandering to straight or otherwise modified planform;<\/li>\n
- the\u00a0occurrence of\u00a0structures affecting the\u00a0longitudinal continuity of\u00a0the\u00a0watercourse \u2013 primarily dams of\u00a0water reservoirs, flow-through ponds and other barriers that disrupt the\u00a0flow natural processes and sediment transport;<\/li>\n
- riparian zone use \u2013 changes between natural vegetation cover, cultural landscape, mosaic landscape, and built-up areas serve as placeholder information for potential changes in\u00a0riverbed morphology.<\/li>\n<\/ul>\n
Basic characteristics of\u00a0the\u00a0defined reaches, such as the\u00a0slope of\u00a0the\u00a0valley and the\u00a0watercourse, confinement index, stream order, and other relevant parameters are available in\u00a0a\u00a0publicly accessible database on the\u00a0HYMOS project website\u00a0[10].<\/p>\n
The\u00a0assessment of\u00a0hydromorphological indicatorsis carried out at the\u00a0level of\u00a0these reaches, and the\u00a0methodology allows a\u00a0choice of\u00a0two assessment approaches. Both approaches comply with legislative requirements and their choice is left to the\u00a0methodology user:<\/p>\n
- \n
- Assessment of\u00a0the\u00a0entire reach length: This approach provides the\u00a0most accurate picture of\u00a0hydromorphological status as it reflects all characteristics within\u00a0the\u00a0entire reach. The\u00a0disadvantage is that it is time-consuming, especially when collecting field data.<\/li>\n
- Assessment on a\u00a0shorter representative \u201csub-reach\u201d: Assessment is carried out on a\u00a0selected sub-reach; subsequently, its characteristics are extrapolated to the\u00a0entire reach. This approach is less time-consuming, however, provides less detailed information on the\u00a0hydromorphological status. The\u00a0choice of\u00a0sub-reach is key to ensuring representativeness of\u00a0the\u00a0results.<\/li>\n<\/ol>\n
Indicators for assessing hydromorphological status<\/span><\/strong><\/span><\/p>\n
The\u00a0indicators used to assess the\u00a0hydromorphological status and its elements (hydrological regime, continuity, and morphological conditions) are based on the\u00a0requirements defined in\u00a0the\u00a0\u010cSN EN 14614 standard. The\u00a0selection of\u00a0indicators is based on current scientific knowledge and their demonstrated relationship to the\u00a0assessed biological components, such as fish, macrophytes, or macroinvertebrates.<\/p>\n
Each indicator is defined in\u00a0terms of\u00a0its function in\u00a0the\u00a0assessment and scope of\u00a0application, i.e. for which types of\u00a0watercourses it is applicable. An overview of\u00a0the\u00a0indicators is given in\u00a0Tab.\u00a01<\/span>, which contains a\u00a0brief description of\u00a0the\u00a0assessment method and specifies to which types of\u00a0watercourses the\u00a0given indicator applies. As opposed to previous approaches, it is no longer necessary to record detailed information for indicators, such as percentages of\u00a0bed substrate types or channel bed elements, for assessment purposes. Instead, the\u00a0degree of\u00a0deviation from the\u00a0reference status in\u00a0categories is directly assessed, which significantly reduces the\u00a0time required for data collection in\u00a0the\u00a0field. Indicators are rated in\u00a0three to five categories, which also contributes to reducing the\u00a0degree of\u00a0subjectivity. Field data can be collected directly via a\u00a0form in\u00a0the\u00a0mobile app (a\u00a0web platform adapted for any mobile device), eliminating the\u00a0need for additional transcription of\u00a0data from paper forms. During the\u00a0testing of\u00a0HYMOS methodology, the\u00a0speed of\u00a0assessment was compared with HEM methodology. The\u00a0comparison carried out on 15 selected sections of\u00a0watercourses showed that actual data collection in\u00a0the\u00a0field using HYMOS methodology was approximately twice as fast as when using HEM methodology.<\/p>\n
Tab.\u00a01. Overview of\u00a0assessed indicators, their scope, assessment method and the\u00a0most common data sources for assessment. Indicators highlighted in\u00a0orange are those evaluated using an alternative approach in\u00a0cases where the\u00a0required data \u2013 such as remote sensing data or data from gauging stations are unavailable. The\u00a0letter next to each indicator denotes its affiliation with a\u00a0specific element of\u00a0the\u00a0hydromorphological status (H = hydrological regime, C = continuity, M = morphological conditions)<\/span><\/h5>\n
![\"\"](\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\")
<\/a>\nPrinciple of\u00a0calculating hydromorphological status<\/span><\/strong><\/p>\n
Indicators are assessed in\u00a0categories, each of\u00a0which is assigned a\u00a0point score. This system allows calculation of\u00a0the\u00a0status of\u00a0all hydromorphological status elements (hydrological regime, continuity, morphological conditions), overall hydromorphological status of\u00a0the\u00a0reach and, subsequently, of\u00a0the\u00a0water body. Scoring is based on the\u00a0MQI methodology\u00a0[7] and was validated and adjusted based on data obtained during the\u00a0project to correspond to the\u00a0conditions of\u00a0the\u00a0Czech Republic. The\u00a0point score of\u00a0category 1, which represents the\u00a0reference status, is always 0 and with an increasing value of\u00a0the\u00a0assessment category, which signals a\u00a0higher degree of\u00a0anthropogenic influence, the\u00a0point score also increases.<\/p>\n
The\u00a0assessment of\u00a0the\u00a0hydromorphological condition is calculated as the\u00a0sum of\u00a0points obtained from the\u00a0evaluation of\u00a0individual indicators, which is then divided by the\u00a0maximum possible score for the\u00a0given indicators. Each indicator influences the\u00a0final assessment to a\u00a0different extent. The\u00a0calculation is performed according to the\u00a0following formula:<\/p>\n
<\/a>\nwhere:<\/p>\n
<\/p>\n
HMS\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 hydromorphological status<\/p>\n
Sassessment\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<\/sub>the\u00a0sum of\u00a0the\u00a0points obtained by assessing the\u00a0indicators<\/p>\n
Smax\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<\/sub>the\u00a0maximum sum of\u00a0the\u00a0points for the\u00a0assessed indicators<\/p>\n
Indicators that are not assessed are not included in\u00a0the\u00a0calculation of\u00a0the\u00a0maximum score. This calculation procedure is also used for the\u00a0individual hydromorphological elements.<\/p>\n
When calculating the\u00a0score, the\u00a0assessment reliability is also considered. If the\u00a0assessment of\u00a0an indicator is less reliable (e.g. due to lack of\u00a0or incomplete data), the\u00a0user marks two assessment categories and then the\u00a0difference between these categories is calculated and the\u00a0deviation caused by this uncertainty is included in\u00a0the\u00a0overall score.<\/p>\n
The\u00a0calculated score for hydromorphology and its components ranges from 0 to 1, with a\u00a0value of\u00a01 corresponding to natural conditions and 0 indicating heavily degraded conditions. Threshold values for individual assessment classes are given in\u00a0Tab.\u00a02<\/span><\/em>. Calculations are performed automatically by the\u00a0software, based on the\u00a0assessment entered into the\u00a0form in\u00a0the\u00a0web app.<\/p>\n
Tab. 2. Threshold values for the assessment of hydromorphological status and its elements<\/h5>\n
<\/a>\nFor reporting purposes, assessment result for the\u00a0entire water body must be provided. This can be calculated using the\u00a0following formula:<\/p>\n
<\/a>\nwhere:<\/p>\n
HMSV\u00da<\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 is\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 hydromorphological status of\u00a0the\u00a0water body<\/p>\n
HMSi<\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 hydromorphological status of\u00a0the\u00a0i\u00a0reach<\/p>\n
li<\/sub>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 the\u00a0length of\u00a0the\u00a0i\u00a0reach<\/p>\n
Water body assessment<\/span><\/strong><\/p>\n
HYMOS methodology was applied to 15 selected water bodies, which are evenly represented in\u00a0all main\u00a0river basins of\u00a0the\u00a0Czech Republic \u2013 three water bodies in\u00a0each river basin. For the\u00a0purpose of\u00a0demonstrating applicability of\u00a0the\u00a0methodology, water bodies were selected that cover different hydromorphological types of\u00a0watercourses, i.e. streams with different slopes (high\/low), in\u00a0confined and unconfined valleys, small and large streams, with different intensities of\u00a0coarse sediment input. Another selection criterion was the\u00a0intention to include water bodies with different intensities of\u00a0anthropogenic pressures. An overview of\u00a0the\u00a0selected water bodies, including their division into reaches, is shown in\u00a0Fig.\u00a01<\/em>.<\/span><\/p>\n
<\/a>\nFig.\u00a01. The\u00a0map depicts the\u00a0selected assessed water bodies (their full names are listed in\u00a0Tab.\u00a03<\/em>), the\u00a0division of\u00a0water bodies into reaches (reaches are colour-marked, their numbering corresponds to Tab.\u00a03<\/em>), and the\u00a0parameters used for this division. It also shows the\u00a0sequential numbering of\u00a0reaches and the\u00a0location of\u00a0sub-reaches where field assessments were conducted (abbreviations used: pr\u016ft. rybn\u00edk = flow-through pond, p\u016fd. tvar = channel planform)<\/h6>\n
Indicators 1 to 8 and 18 (listed in\u00a0Tab.\u00a01<\/span><\/em>) were assessed over the\u00a0entire reach length based on remote sensing data. Indicator 9, relating to the\u00a0periodicity and extent of\u00a0floodplain\u00a0flooding, was assessed over the\u00a0entire length, if the\u00a0relevant remote sensing data were available (floodplain\u00a0extent layer for a\u00a05-year recurrence interval). The\u00a0remaining indicators were assessed within\u00a0shorter sub-reaches (Fig.\u00a01<\/span><\/em>). The\u00a0sub-reaches were defined based on an analysis of\u00a0the\u00a0land use in\u00a0the\u00a0strip around the\u00a0watercourse, aerial photographs, virtual<\/p>\n
RESULTS AND DISCUSSION<\/h2>\n
A\u00a0total of\u00a015 water bodies were assessed, which were divided into 50 reaches. For each of\u00a0these reaches, both the\u00a0score for individual elements of\u00a0hydromorphological assessment (hydrological regime, continuity, morphological conditions) and overall hydromorphological status were calculated. Each reach was also assigned to the\u00a0corresponding classification class. The\u00a0summary results are presented in\u00a0Tab.\u00a03<\/span><\/em>.<\/span><\/p>\n
Tab.\u00a03. Results of\u00a0the\u00a0assessment of\u00a0selected water bodies \u2013 results for river reaches and entire water bodies<\/h5>\n
<\/a>\nAlmost half of\u00a0the\u00a0assessed reaches were classified as class 3 based on the\u00a0degree of\u00a0hydromorphological impact. Eleven reaches were in\u00a0good status, nine in\u00a0very good, and seven were assessed as poor. No reach was classified as bad (classification status 5) High status was typical for parts of\u00a0the\u00a0watercourse in\u00a0the\u00a0upper reaches with a\u00a0steep slope, often in\u00a0confined valleys. However, these parts usually only represent a\u00a0smaller proportion of\u00a0total water body length. Longer reaches with high status are only found in\u00a0the\u00a0\u0158\u00ed\u010dka water body, from its source to its confluence with the\u00a0Lu\u010dina watercourse. Reaches in\u00a0confined valleys, where the\u00a0intensity of\u00a0anthropogenic modifications is usually lower (e.g. lower part of\u00a0Hrejkovick\u00fd stream), were also found to be in\u00a0good or high status. Reaches of\u00a0Lipoltovsk\u00fd stream, the\u00a0meandering parts of\u00a0the\u00a0Orlice and the\u00a0\u0160lapanka water bodies can also be described as ecologically valuable.<\/p>\n
Analysis of\u00a0the\u00a0main\u00a0anthropogenic pressures and the\u00a0response of\u00a0watercourses to their effects (Fig.\u00a02<\/span><\/em>) showed that the\u00a0most common reason for the\u00a0impaired result of\u00a0hydromorphological assessment was modification of\u00a0the\u00a0channel planform. This type of\u00a0modification is often associated with low cross-sectional variability and insufficient presence of\u00a0the\u00a0corresponding riverbed elements. Other pressures include disruption of\u00a0the\u00a0watercourse longitudinal continuity, which limits sediment transport and fish migration. In\u00a0more than one third of\u00a0cases, the\u00a0absence of\u00a0bank erosion and large wood also contributed to lower assessment. Field data show that, despite modifications to the\u00a0cross-sectional profile, banks are usually not stabilized over long reaches. This provides a\u00a0suitable condition for spontaneous renaturation during floods, especially in\u00a0streams with higher energy (watercourses with a\u00a0more pronounced slope, flow rate, and narrower undersized channel).<\/p>\n
<\/a>\nFig.\u00a02. Relative frequency of\u00a0occurrence of\u00a0indicators (main\u00a0pressures) contributing\u00a0to\u00a0the\u00a0impaired status of\u00a0assessed reaches<\/h6>\n
For the\u00a0purposes of\u00a0reporting under the\u00a0WFD, it is necessary to calculate the\u00a0hydromorphological status and its elements for water bodies. The\u00a0assessment of\u00a0selected water bodies is given in\u00a0Tab.\u00a03<\/span><\/em>. However, this approach has certain\u00a0limits. Water bodies usually include different hydromorphological types and are exposed to different anthropogenic pressures that differ in\u00a0intensity; from this point of\u00a0view, they are not homogeneous. The\u00a0calculated classification level value is a\u00a0weighted average of\u00a0assessments for individual water body reaches. Analysis of\u00a0selected water bodies shows that the\u00a0calculation for one body can only be sufficient for large watercourses, where anthropogenic influence is manifested over long distances.<\/p>\n
Examples are the\u00a0Oh\u0159e water body from the\u00a0Chomutovka stream to\u00a0the\u00a0mouth of\u00a0the\u00a0Elbe, the\u00a0Lu\u017enice water body from the\u00a0Ne\u017e\u00e1rka iver to the\u00a0Ko\u0161\u00ednsk\u00fd stream, and the\u00a0Ostravice water body from the\u00a0Mor\u00e1vka river to the\u00a0Lu\u010dina stream. In\u00a0the\u00a0case of\u00a0smaller and medium-sized watercourses, assessment for the\u00a0water body is usually too aggregated. A\u00a0good example is the\u00a0B\u011bl\u00e1 water body, from the\u00a0source to the\u00a0Dlouh\u00e1 strouha stream, where reaches in\u00a0a\u00a0confined and unconfined valley alternate, and each of\u00a0these reaches shows a\u00a0different degree of\u00a0anthropogenic influence (Fig.\u00a03<\/span><\/em>). Although it is necessary to calculate values for the\u00a0water body for reporting purposes, more detailed information for individual reaches also represents an important basis that can support more accurate identification of\u00a0critical reaches and more effective design of\u00a0measures by environmental protection authorities and watercourse\u00a0managers.<\/p>\n
<\/a>\nReach 1 \u2013 confined valley with a\u00a0steep slope (over 2\u00a0%), no anthropogenic pressures (high status)<\/h6>\n
<\/a><\/h6>\nReach 2 \u2013 unconfined valley with a\u00a0steep slope (over 2\u00a0%), modified channel morphology and disruption of\u00a0longitudinal continuity (moderate status)<\/h6>\n
<\/a><\/h6>\nReach 3 \u2013 confined valley with a\u00a0slope over 2\u00a0%, anthropogenic pressures caused by local disruption of\u00a0longitudinal continuity and limited connectivity between valley slopes and the\u00a0channel due to road infrastructure (good status)<\/h6>\n
<\/a><\/h6>\nReach 4 \u2013 unconfined valley with a slope of 0.5\u20132 %, local modifications of\u00a0the\u00a0cross-sectional profile (good status)<\/h6>\n
<\/a><\/h6>\nReach 5 \u2013 unconfined valley with a\u00a0slope of\u00a00.5\u20132\u00a0%, flowing through a\u00a0village
\nand its built-up area (moderate status)<\/h6>\n<\/a>\nReach 5 \u2013 unconfined valley with a slope of 0.5\u20132 %, flowing through a village and its built-up area (moderate status)<\/h6>\n
Fig.\u00a03. Reaches of\u00a0the\u00a0B\u011bl\u00e1 water body from its source to the\u00a0Dlouh\u00e1 strouha stream, illustrating the\u00a0variability of\u00a0physico-geographical conditions and the\u00a0influence of\u00a0anthropogenic pressures<\/h6>\n
CONCLUSION<\/h2>\n
In\u00a0this paper, we have presented a\u00a0new methodology for assessing hydromorphological status of\u00a0flowing water bodies. Compared to previous methodologies, the\u00a0main\u00a0advantages can be considered the\u00a0following:<\/p>\n
\n- \n
- Working with distance data
\n10 out of\u00a019 indicators can be assessed based on remote sensing data, with selected indicators already being assessed within\u00a0the\u00a0project.<\/p>\n
\n<\/li>\n - Reducing time requirements
\nThe\u00a0defined methodology, software, and apps enable fast and efficient data collection in\u00a0the\u00a0field and immediate assessment of\u00a0hydromorphological status without the\u00a0need for transcribing field data and further calculations. HYMOS methodology is up to twice as fast as HEM; when testing during the\u00a0project, its user needed only half the\u00a0time compared to the\u00a0user of\u00a0HEM methodology.<\/p>\n
\n<\/li>\n - Reducing subjectivity of\u00a0assessment
\nAssessing indicators in\u00a0categories and the\u00a0method of\u00a0defining the\u00a0assessment increases the\u00a0probability that two different assessors will assess the\u00a0same indicator identically.<\/p>\n
\n<\/li>\n - Ensuring consistency between the\u00a0calculated hydromorphological status and the\u00a0conditions observed in\u00a0the\u00a0field
\nThe\u00a0defined assessment gives the\u00a0assessor greater freedom in\u00a0the\u00a0assessment, thus preventing situations where, in\u00a0the\u00a0past, a\u00a0watercourse was assessed according to a\u00a0type that does not correspond to its actual character.<\/p>\n
\n<\/li>\n - Analysis of\u00a0main\u00a0anthropogenic pressures and response of\u00a0watercourses to their effects
\nAfter calculation, the\u00a0software shows which indicators contributed most to poor hydromorphological status, which allows for precise identification of\u00a0the\u00a0main\u00a0anthropogenic pressures acting in\u00a0the\u00a0assessed reach.<\/li>\n<\/ol>\nHYMOS methodology meets current requirements of\u00a0the\u00a0WFD and the\u00a0\u010cSN\u00a0EN\u00a014614 standard for assessment of\u00a0hydromorphological elements of\u00a0water bodies; it also allows for assessment of\u00a0watercourses that are not defined as water bodies. In\u00a0the\u00a0methodology, watercourses are seen as dynamically changing systems, which shifts the\u00a0emphasis to assessment of\u00a0processes such as sediment transport, bank erosion, or riverbed development. The\u00a0methodology also considers anthropogenic changes above the\u00a0assessed reach, which can affect processes and shapes in\u00a0the\u00a0given reach. Although the\u00a0methodology is designed for a\u00a0comprehensive assessment of\u00a0these processes, it is not intended for monitoring very small changes that are difficult to define with a\u00a0categorized assessment. Compared to previous methodologies, HYMOS methodology brings significant changes in\u00a0the\u00a0approach to assessing hydromorphological status. Nevertheless, a\u00a0number of\u00a0recorded parameters, such as transverse structures in\u00a0the\u00a0channel or stabilization of\u00a0riverbanks and riverbed, remain\u00a0the\u00a0same or differ only minimally. Thanks to this, data obtained using older methodologies can also be used for assessment according to HYMOS methodology, especially if the\u00a0original definition of\u00a0the\u00a0assessed reaches is maintained. In\u00a0the\u00a0event of\u00a0a\u00a0change in\u00a0their definition, the\u00a0need to reassess percentage values related to the\u00a0length of\u00a0the\u00a0reach cannot be ruled out in\u00a0order to correspond to the\u00a0new definition.<\/p>\n
HYMOS methodology allows for assessment of hydromorphological status at the level of individual homogeneous reaches, which provides valuable information for detailed analyses and planning of measures. Based on these partial assessments, an aggregated value of hydromorphological status for the entire\u00a0water body can then be calculated, which is required for reporting purposes in\u00a0accordance with the\u00a0WFD. This combination of\u00a0detailed and aggregated approaches makes HYMOS methodology a\u00a0flexible tool that can be used not only for strategic planning at the\u00a0water body level, but also for assessment of\u00a0local reaches in\u00a0connection with implemented or planned measures.<\/p>\n
Due to the\u00a0project timeframe, it was not possible to use HYMOS methodology for assessing the\u00a0hydromorphological status of\u00a0watercourses in\u00a0the\u00a0third planning cycle. However, its application is expected in\u00a0subsequent planning cycles, which are planned at least at the\u00a0national level. The\u00a0importance of\u00a0the\u00a0hydromorphological status of\u00a0watercourses is also highlighted in\u00a0the\u00a0Nature Restoration Law (Regulation (EU) 2024\/1991), approved last year, which places emphasis on the\u00a0restoration of\u00a0free-flowing rivers. HYMOS methodology\u00a0[9] was developed with these requirements in\u00a0mind and provides broad analytical and methodological support for their fulfilment.<\/p>\n
Acknowledgements<\/h3>\n
The\u00a0creation of\u00a0the\u00a0methodology and the\u00a0preparation of\u00a0this article were supported by the\u00a0project of\u00a0the\u00a0Technology Agency of\u00a0the\u00a0Czech Republic No. SS05010135 \u201cDevelopment of\u00a0a\u00a0methodology for monitoring and assessing hydromorphological characteristics of\u00a0watercourses\u201d.<\/em><\/p>\n
The\u00a0Czech version of\u00a0this article was peer-reviewed, the\u00a0English version was\u00a0translated from the\u00a0Czech original by Environmental Translation Ltd.<\/p>\n","protected":false},"excerpt":{"rendered":"
Assessment of the hydromorphological status and its elements (hydrological regime, continuity, morphological conditions) is part of the monitoring of the ecological status of water bodies. Hydromorphology, as a supporting component of biological assessment, has a significant impact on living organisms in aquatic ecosystems. Based on the Ministry\u2019s request, a new methodology for assessing the hydromorphological status of water bodies category rivers (HYMOS) was developed within the TA CR project. This methodology takes into account new requirements and current knowledge in the field of hydromorphology, while also minimizing the drawbacks of previous methodologies, particularly regarding time and cost efficiency in the assessment process. <\/p>\n","protected":false},"author":8,"featured_media":35028,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[86,93],"tags":[3799,3800,791,786],"coauthors":[3762,3763,3764,597,173,3765],"class_list":["post-35349","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydraulics-hydrology-and-hydrogeology","category-two-articles","tag-hydromorphological-assessment","tag-hymos-methodology","tag-water-body","tag-water-framework-directive"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/35349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=35349"}],"version-history":[{"count":5,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/35349\/revisions"}],"predecessor-version":[{"id":35384,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/35349\/revisions\/35384"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/35028"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=35349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=35349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=35349"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=35349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- Working with distance data
- for indicators expressing the\u00a0\u201cfunctionality\u201d of\u00a0a\u00a0watercourse and its response to anthropogenic pressures (e.g. bed substrate, bed elements), reference conditions are defined as the\u00a0presence of\u00a0forms and processes that are expected for a\u00a0watercourse located in\u00a0given physical-geographical conditions (e.g. valley slope and shape, intensity of\u00a0sediment input).<\/span><\/li>\n<\/ul>\n
- for indicators expressing the\u00a0effects of\u00a0anthropogenic pressures (e.g.\u00a0bank\u00a0stabilization, channel bed modification), reference conditions are defined as the\u00a0absence of\u00a0pressures or their minimal presence, which does not have a\u00a0significant impact on fluvial processes, morphology, or\u00a0natural development of\u00a0the\u00a0channel;<\/span><\/li>\n
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