Skip to main content


Title: River quality survey NRA Northumbria and Yorkshire region GQA assessment 1994. Part 1 Reach classification. Freshwater rivers and canals
Author: National Rivers Authority Northumbria and Yorkshire Region
Document Type: Monograph
To allow the development of a National method of evaluating water quality, the rivers in all the NRA regions of England and Wales have been divided into reaches, which are numbered using a coding system based on the hydrological reference for each river basin. Each classified reach then has a chemistry sample point assigned to it and these sample points are regularly monitored for Biochemical Oxygen Demand (BOD), Dissolved oxygen (DO) and Total Ammonia. The summary statistics calculated from the results of this sampling are sent to a National Centre where the GQA Grades are calculated. A National report is produced and each region can then produce more detailed reports on the quality of their own rivers. For Northumbria and Yorkshire Region, this Regional Report has been divided into two parts. This report represents the part 1 (Reach classification). This report contains a listing of the river reaches within the region, with their start and finish grid reference, approximate length, and the 1990 and 1994 GQA class for each reach. The reference code of the chemistry sample point used to classify the reach is also included. A sample point may classify several reaches if there are no major discharges or tributaries dividing those reaches. The sample point used to classify a reach may change and the classification is therefore calculated using the summary statistics for each sample point that has been used over the past three years. In a few cases, this results in a reach having a classification for 1994 although there is no sample point listed for the reach.
Publisher: National Rivers Authority
Publication Date: 1995
Publication Place: Leeds
Subject Keywords: RiversWater qualityNational planningPollutant load
Geographic Keywords: EnglandWales
Extent: n.p. [136]
Total file downloads: 71

Download PDF    Display PDF in separate tab