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<br /> <br />f!2 <br />~f <br />"!!--. <br />t' <br /> <br />... <br /> <br />J,' <br /> <br />..' <br /> <br />'T <br /> <br />RECe.\'JEO <br /> <br />~~~ 'l 7 ~99 <br />coloradO w~srd <br />consllf'l"UOll <br /> <br />!I <br /> <br />ELSEVIER <br /> <br />Journal <br />of <br />Hydrology <br /> <br />lournal of Hydrology 216 (1999) 137-144 <br /> <br />Technical note <br /> <br />Recording rainfall stratigraphy: a modified storage gauge for <br />measuring rainfall events <br /> <br />E.J. Brown, W.E. Bardsley* <br /> <br />!r <br /> <br />DlIpartmenr of earth Science!, University of Waikato. Private Bag 3105, Hamilton New ~aland <br />Received 7 January 1998; received in revised form 4 November 1998; accepted 16 November 1998 <br /> <br />Abstract <br /> <br />Standard storage rain gauges preserve nothing of the magnitude of individual rainfall events. A low~technology modified <br />storage gauge is described which records event magnitudes but not their timing. A float in the gauge contains a collimated <br />radioactive source which has its intensity calibrated so that each rainless period generates a line on a protected film. Rainfall <br />event magnitudes are recorded as the vertical inrervals between consecutive horlzontallines on the film. That is. the record <br />represents a stratigraphic column of rainfall events at the gauge location. A network of the gauges allows significant rainfall <br />event "layers" to be linked through space analogous to stratigraphic correlation. iO 1999 Elsevier Science B.V. All rights <br />reserved. <br /> <br />Keywords: Rainfall; Measurement; Techniques; Instruments <br /> <br />1. Introduction <br /> <br />The importance of accurately measuring small- <br />scale spatial variation of rainfall events has been iden- <br />tified in a variety of scientific studies (Berndtsson and <br />Niemczynowicz. 1988; Goodrich et al.. 1995; Faures <br />et aI., 1995; Desa and Niemczynowicz, 1996; Loukas <br />and Quick, 1994; Loukas and Quick. 1996. However, <br />there may be considerable cost involved in setting up <br />a sufficiently large number of recording gauges to give <br />the required degree of spatial resolution of the events. <br />At the more basic level of rainfall recording, <br />national networks of storage gauges contribute on- <br />going input to climatology and hydrology data <br />bases. Such networks are inexpensive but provide <br />limited rainfall infonnation. For example, monthly <br />storage gauge readings do not allow determination <br /> <br />. Corresponding author. Fax: + 64 7 854 0115; e-mail: <br />web@waikalo.ac.nz <br /> <br />of whether the rainfall totals represent a few large <br />rainfall events or the combined effect of a large <br />number of smaIl events. <br />For both project-specific and basic rainfall record- <br />ing, it would be desirable to have low-cost storage <br />gauges available which preserve the record of rainfall <br />events for later analysis. This article describes a <br />simple modified storage gauge which has the potential <br />to meet this need without creating too much additional <br />cost. <br /> <br />2. The experimental gauge <br /> <br />The new gauge is henceforth referred to as the <br />"stillstand" rain gauge because it is essentially a <br />storage gauge modified to allow a marking process <br />to take place at the gauge water level during rainless <br />periods. The stillstand mark is created using a float <br />within the gauge, which holds a sealed radioactive <br /> <br />0022.1694199/$ _ see front matter C 1999 Elsevier Science B.V. All righls reserved. <br />PH: 50022-1694(98)00294.7 <br />