Abstract

The Samal ' a River in western Guatemala is critical for sustaining diverse agricultural production systems, from staple crop production in the upper basin to sugar cane in the lowlands. The streamflow from the Samal ' a River also supports hydroelectric power generation within the basin. The wat... Show moreThe Samal ' a River in western Guatemala is critical for sustaining diverse agricultural production systems, from staple crop production in the upper basin to sugar cane in the lowlands. The streamflow from the Samal ' a River also supports hydroelectric power generation within the basin. The watershed is home to more than a hundred settlements including cities, towns, and villages, some of which have experienced extreme hydrological events, including destructive flooding from the river. However, the Samal ' a River streamflow record, only 38 years in length (1979-2016), is too short to assess the full range of hydrological variability for this economically important region, including Guatemala's second largest city -Quetzaltenango. This paper presents a tree-ring based reconstruction of mean August streamflow for 125 years (1889-2013). Our results suggest that annual tree-ring width measurements from Abies guatemalensis are correlated with monthly mean streamflow records in the upper Samal ' a River basin. This association seems to be modulated in part by variability in the ENSO 3.4 region in the Pacific Ocean, suggesting decreased streamflow during the warm events of the sea surface temperature in the Pacific Ocean. The record indicates that single year events of low streamflow dominate the record. Nevertheless, a period of up to 8 consecutive years below-average streamflow is shown in the record between 1905 and 1912. Overall, this extended record of streamflow suggests that tree-ring studies in the area have the potential to provide useful inputs in the future that can be utilized by stakeholders and decision-makers within the Samal ' a watershed involving the management of discharge for crop irrigation, hydropower production, and disaster mitigation. Show less