Praxistest zweier Verfahren zur Unverhältnismäßigkeitsprüfung

摘要

Currently, only 8.2 % of German surface water bodies reach European Water Framework Directive's ambitious goal of a "good ecological status" and many will presumably not reach the aim by 2027, too. The Directive allows less stringent environmental objectives, if a good status is not feasible or disproportionally expensive. Two related procedures to assess the disproportionality of costs, the benchmark approach and the average cost approach, are presented and empirically applied for 164 surface water bodies of a German federal state. The tests show that both approaches are suitable to support the competent authorities in finding consistent and transparent justifications why for certain water bodies reaching a good status might be disproportional. Several variations of the approaches are investigated and sensitivity analyses are conducted for those parameters, which are (necessarily) based on value judgments. The fields of application of the approaches as well as their limitations are discussed. Particularly, if measures for a water body have substantial upstream or downstream effects on other water bodies, as it is typical for measures improving passability, both tested approaches should be replaced by a cost-benefit assessment covering all affected water bodies.