Identification
- Title
- NRW Freshwater Lake Macroinvertebrates
- Abstract
Freshwater macroinvertebrates are used as an indicator of water quality and Lake flow requirements due to the relative immobility and abundance. This dataset contains site, sample, metric and taxa information from freshwater Lake macroinvertebrate surveys carried out across Wales by Natural Resources Wales and former Environment Agency Wales since 1997 and onwards. These surveys are conducted as part of on-going monitoring of Lake water quality for legislative requirements and to meet business needs.
Lake invertebrate data is collected using different sampling methods. Lake invertebrate kick samples use the same 3-minute technique as in rivers and are used as part of the WFD process to assess acidification within lakes. Chironomid Exuviae Technique (CPET) which assesses the population of Chironomids within the lake to help assess nutrient and pH conditions within the waterbody.
A strict methodology is applied when sampling for freshwater Lake macroinvertebrates. There is a core network of sites which are monitored on a three-yearly rolling programme. These sites are located where risk assessment has shown significant risk of failure of WFD ecological quality standards. In addition sites may be sampled for investigative work, or on an ad hoc basis. Sampling areas are located with a larger survey area and must be representative of the overall survey area. Once samples are collected they are sent NRW ecology laboratories for identification using standard methodologies, employing a strict Analytical Quality Control (AQC) procedure.
Once the data is collated in the central database, it has then been extracted and QA'd before being published. It is important to note that this dataset will include some sampling events from recent months where sampling has been undertaken but laboratory analysis has not been completed, therefore the full complement of taxa for that sampling event will not yet be uploaded. These records will be completed in future data uploads from NRW to the NBN Atlas. This dataset also includes records for some non-macroinvertebrate species, such as birds and fish, that were either observed or collected during sampling. Any non-target organisms collected during sampling were immediately returned to the Lake.Redactions
Some information has be redacted to make the data openly available. This includes
- Third party data
- Data collected for ongoing investigations
- Cancelled or incomplete surveys
- Location of protected species where releasing details of their location could have a detrimental effect e.g. freshwater pearl mussels.
Update Frequency
This data is continually updated. CPET samples are taken between April and October (4 samples spread evenly) whilst lake kick samples are taken in Spring only (March-May). Data from survey seasons is often not enter at the time of capture and can be several months before its is entered into the system. The external dataset is updated monthly to include new data, and may also contain corrections to previously published data due to quality assurance work.
Information Warnings
- We do our best to avoid data quality problems, but as these datasets reflect the data we hold, they may contain errors
- The data is provided as a set of related data tables due to the quantity and structure of the data. A basic understanding of ecology and relational data is assumed.
- Data related to pollution incident investigations or protected species information is not released as locational information of these sites may be detrimental to ongoing investigations or species protection.
- Not all sites have environmental base data listed.
Further Information
Please see the following documents for further information
Attribution statement
Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
- Licence
- Open Government Licence for Public Sector Information (OGL)
-
Copyright:
- Publication date
- 22 April 2025
- Type
- Spatial data
- Category:
- Environment
- Regions
- Global
- Approved
- Yes
- Published
- Yes
- Featured
- No
- Group
- Natural Resources Wales
Information
- Spatial extent
- Projection system
- EPSG:27700
- Extension x0
- 146597.199797902
- Extension x1
- 355308.0
- Extension y0
- 164586.296917809
- Extension y1
- 395984.199957072
Features
Contact
- opendata@naturalresourceswales.gov.uk
- Organisation
- Natural Resources Wales
References
- Link online
- /layergroups/geonode:nrw_lake_macroinvertebrates
- Metadata page
- /layergroups/geonode:nrw_lake_macroinvertebrates/metadata_detail