HOMS COMPONENT

THE INSTRUMENTATION OF FLAT LOW-LYING CATCHMENTS

1.   Purpose and objectives

     To give an account of the techniques employed in instrumenting flat, low-lying catchments for research purposes; to address the problem that most available information on catchment instrumentation applies to areas of high relief.

2.   Description

     This component is a report containing a detailed account of the techniques employed in instrumenting three flat catchments in the UK. The catchment type is defined as below sea-level and requiring pumping to maintain drainage artificially.  Details and maps of the three catchments are given.

     Throughout the report various techniques and problems are discussed for low-lying areas in general, illustrated by examples from the three catchments. Existing data - e.g. water level, rainfall, land level and data from pumping stations - are assessed for their usefulness. Factors affecting the selection of catchments suitable for research are then discussed. These include definition of the boundary and the exact nature of the drainage layout, leakage from the catchment, and the problems arising from culverts and sluices, multi-site pumping and drain obstructions. Catchment surveying is also briefly discussed.

     The report goes on to describe ways of measuring hydrological components including water level, flow rate, rainfall and groundwater levels. Particular reference is made to the density of instrumentation and the type of structures found to be appropriate in catchments with pumping stations and drains. Several photographs give illustrations from the three experimental catchments. Problems affecting measurements - wind, tides, drain weed and vandalism - are discussed and some solutions suggested. There is also a brief reference to data handling techniques.

     Although no data are presented in this report except as examples, a summary of data sets resulting from the experiments in the three catchments forms an Appendix.

3.   Input

     Not applicable.

4.   Output

     Not applicable.

5.   Operational requirements and restrictions

     Not applicable.

6.   Form of presentation

     Report in English: Institute of Hydrology Report no. 105, 48 pages, 19 plates, 11 figures, 5 tables.

7.   Operational experience

     Not applicable.

8.   Originator and technical support

     Institute of Hydrology, Wallingford, Oxon OX10 8BB, UK.

9.   Availability

     From the HOMS National Reference Centre for the United Kingdom.

10.  Conditions on use

     Free of charge.

Last updated: 05 JUL 94)
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