Large numbers of dead freshwater crayfish were reported in the…
WFD update – assigning status to all unmonitored identified waterbodies
The WFD requires that all identified waterbodies are assigned a status to determine if a waterbody has achieved its environmental objective. Just under 60% of Ireland’s surface and groundwater bodies are assigned status based on the results of monitoring. This means that the remaining waterbodies that are not monitored (i.e. 40%) must be assigned a status by other means. These assigned statuses are now available on catchments.ie data pages and the EPA Water Map. This article briefly outlines the current methodologies used to assign status to unmonitored identified WFD river waterbodies.
The Water Framework Directive requires that status be assigned to all identified surface and groundwater bodies and sets out in detail how status should be assigned. Monitoring all water bodies is not logistically feasible so the EPA has grouped similar water bodies together and interpolated data for the purpose of assigning status. This is allowed for by the Directive if enough water bodies are monitored within a group to provide an accurate assessment of status of that group.
In Ireland, just under 60% of identified water bodies have been assigned a status based on the results of monitoring which means that 40% of waterbodies require status to be assigned by other means such as grouping and expert judgement.
Assigning status to these water bodies has important implications for regulatory authorities who are unable to evaluate proposed works by reference to the requirements of the Water Framework Directive without status first being assigned by the EPA for identified water bodies.
Assigning status to unmonitored waterbodies
A similar approach based on water body grouping and where necessary the use of expert judgement has been used for each of the surface water categories (i.e. rivers, lakes, estuaries and coastal waters). For example, the steps taken to assign status to unmonitored river water bodies was as follows:
- a statistical model using updated datasets was used to group water bodies with similar physical characteristics and catchment pressures. Information on water body typology, risk assessment, and modelled nutrient loadings (SLAM model) was used in this step. A monitored water body within the group of water bodies was used to donate status to its closest unmonitored neighbour.
- any available supplementary information about the unmonitored water body was used to validate the outputs of the first step. Supplementary information was taken from local catchment assessments undertaken by LAWPRO; available information on nutrient levels, the status of water bodies directly upstream or downstream of the unmonitored water body and information on land use (e.g.% arable, % urban). Where the supplementary information was not in agreement with the outputs of step 1 expert judgement was used to change the output if there was sufficient evidence in the supplementary information to do so.
The outcome of applying this combined approach is that 98% (3120 water bodies) of all identified river water bodies (3192) have now been assigned a status based either on the results of monitoring (74%), water body grouping (17%) or expert judgement (7%). The results obtained from all methods combined is consistent with the results from the monitored water bodies.
Because of these changes, over 93% of all WFD water bodies in the State will have a status reported for the 3rd Cycle River Basin Management Plan. European reporting allows status to be reported based on monitoring, grouping or expert judgement. This percentage is now more in line with the level of reporting seen across Europe where close to 96% of all surface water bodies had a status reported in the last RBMP.
Status can be viewed for all waterbodies on the EPA Water Map and also on the individual waterbody pages on catchments.ie Data pages. The data pages also indicate how status was assigned and the confidence in that assessment.