Report No FR0391
URBAN RUNOFF DATA COLLECTION
The WURD database has been strengthened by the addition of more rainfall-runoff events of greater duration and extremity than previously. Additional knowledge has been gained concerning the accuracy and reliability of conventional flow measuring techniques in large diameter sewer pipes.
The main objective of this work has been to identify additional rainfall runoff events from instrumented urban catchments in Coventry, Leicester, Derby and Oxhey. These data are then included in the national WURD database, held at the Institute of Hydrology, for possible future updates of sewerage hydraulic analysis models.
Additionally, this report compares the modern rainfall runoff response for the Oxhey catchment with data collected in the 1950's.
Oxhey also provided the opportunity to evaluate the performance of the doppler velocity and depth method of sewer flow measurement in a large diameter pipe.
The limitations of existing sewerage hydraulic models are apparent to many users. Many of these limitations arise from the paucity of relevant data for model development.
Over time the size and integrity of an urban catchments impervious area will change and therefore the runoff response might be expected to alter.
Doppler velocity and depth flow metering is commonly used in sewer flow surveys. Although originally this method was designed for pipes up to 0.45 m in diameter it is now commonplace in much larger pipes.
The data collection programmes at Coventry, Leicester and Derby are terminated in March 1994.
The data collection programme at Oxhey is continued so that:
Unprocessed gully meter data, held at The Institute of Hydrology, for Bracknell, Wallingford, Nottingham and Stevenage are filed in the WURD database.
VI RESUME OF CONTENTS
This report briefly describes the urban catchments at Coventry, Leicester, Derby and Oxhey and how they have been instrumented. The twelve events that have been added to the WURD database are presented graphically, together with some summary statistics.
Data have been collected at Oxhey to assess the doppler velocity and depth flow measurement technique and to investigate how runoff from the catchment may have changed since the 1950's. These data are presented graphically and some initial conclusions made.
Copies of the report are available from FWR, price £15.00, less 20% to FWR Members.