Interception loss from the Tamaulipan matorral thornscrub of north-eastern Mexico: an application of the Gash analytical interception loss model

In a semi-arid plant community dominated by the Tamaulipan matorral of north-eastern Mexico the quantitative importance of interception loss and the applicability of the Gash analytical rainfall interception loss model were evaluated. Interception loss was estimated from measurements of incident precipitation and throughfall. Rainfall was measured in one rain gauge, and throughfall in 220 cylindrical and four trough collectors randomly located within a 30 m×20 m plot. A total of 36 rainfall events were observed from September 1995 to April 1997. An independent interception loss data set collected from April 1997 to March 1998 was utilized to test the goodness of fit of the Gash analytical model to rainfall interception. Total observed interception loss was 17.053% and 16.055% for the cylindrical and trough collector systems, respectively, while total predicted interception loss, employing the Gash model, was 116.058 mm (17.054%) and 104.056 mm (16.055%), respectively. The Gash model fitted the independent data set well because it estimated 84.051 mm (18.054%) while observed interception loss was 83.056 mm (18.053%). Possible methods of improving interception loss estimates are also addressed.