River Habitat Modification Class England (2025)

River Habitat Survey Habitat Modification Score (HMS) and Habitat Modification Class (HMC) is an indication of artificial modification to river channel morphology. To calculate the HMS for a site, points are allocated for the presence and extent of artificial features such as culverts and weirs and also modifications caused by the re-profiling and reinforcement of banks (Habitat Modification Score Rules 2003). Greater and more severe modifications result in a higher score. The cumulative points total provides the Habitat Modification Score (HMS). A Habitat Modification Class (HMC) protocol has been developed which allocates the condition of the channel in a site to one of five modification classes, based on the total score (1 = near-natural; 5 = severely modified). In contrast to HQA, higher HMS scores reflect more artificial intervention and modification of the river channel within a site. RHS made an important contribution to development of the CEN guidance standard for assessing the hydromorphological features of rivers and is a recommended method for the agreed protocol for field survey and recording of morphological features. RHS was also used to help develop and test the associated CEN guidance standard on determining the degree of modification on river hydromorphology. In the UK, RHS has been used for several Water Framework Directive (WFD) purposes, helping to identify water bodies in ‘reference condition’, those classified as ‘heavily modified’ and also assessing morphological pressures affecting river catchments. The STAR (STAndardisation of River Classifications) project was a research initiative funded by the European Commission and was completed in 2005. The main aim was to provide standard biological assessment methods compatible with WFD requirements. It also set out to develop a standard for determining the class boundaries of ‘ecological status’ and another one for inter-calibrating existing methods. In Austria, The Czech Republic, Denmark, Germany and Italy ‘core’ RHS sites were chosen to reflect a gradient in habitat and morphology degradation. Results from the STAR project were published in a special issue of Hydrobiologia in 2006.河流生境调查生境改造评分（Habitat Modification Score, HMS）与生境改造等级（Habitat Modification Class, HMC）是表征河道地貌受人工改造程度的量化指标。为计算某一调查点位的HMS，需依据涵洞、堰坝等人工设施的存在情况与影响规模，以及岸坡重塑与加固引发的河道改造情况赋予对应分值（依据2003年版《生境改造评分规则》）。改造程度越高、影响越严重，所得累计分值也就越高，所有分值的累计总和即为该点位的生境改造评分（HMS）。研究人员已开发生境改造等级（HMC）评定规程，可根据点位的总评分将河道状况划分为5个改造等级：1级代表近自然状态，5级代表严重改造状态。与栖息地质量评估（HQA）不同，HMS分值越高，代表点位内河道受到的人工干预与改造程度越强。河流生境调查（River Habitat Survey, RHS）对欧洲标准化委员会（Comité Européen de Normalisation, CEN）河流水文地貌特征评估指南标准的制定具有重要贡献，同时也是野外调查与记录河道地貌特征的公认规程推荐方法。RHS还被用于协助制定并测试欧洲标准化委员会（CEN）有关评估河流水文地貌改造程度的配套指南标准。在英国，RHS已应用于多项《水框架指令》（Water Framework Directive, WFD）相关工作，包括识别处于“参考状态”与“严重改造状态”的水体，以及评估影响河流流域的地貌压力因素。河流分类标准化（STAndardisation of River Classifications, STAR）项目是由欧盟委员会资助的研究计划，于2005年完成，其核心目标是提供符合《水框架指令》（WFD）要求的标准化生物评估方法。此外，该项目还致力于制定“生态状态”等级边界标准，以及搭建现有评估方法的互校准框架。在奥地利、捷克共和国、丹麦、德国与意大利，研究人员选取了“核心”RHS调查点位，以覆盖生境与地貌退化的梯度范围。STAR项目的研究成果于2006年发表于《水生生物学（Hydrobiologia）》期刊特刊。