Temporal Changes in Streamflow and Attribution of Changes to Climate and Landuse in Wisconsin Watersheds

Abstract

Previous historic trends analyses on 21st Century hydrologic data in the United States generally focus on annual flow statistics and have continued to use USGS hydro-climatic data network (HCDN) stations, although post-1988 diversions and runoff regulations are not reflected in the HCDN. Using a more recent dataset, Geospatial Attributes of Gages for Evaluating Streamflow, version II (GAGES II), compiled by Falcone (2012), which includes more watersheds with reference conditions, a comprehensive analysis of changes in seasonal, and annual streamflow in Wisconsin watersheds is demonstrated. Given the pronounced influence of seasonal hydrology in Wisconsin watersheds, the objective of this study is to elucidate the nature of temporal (annual, seasonal, and monthly) changes in runoff. Considerable temporal and regional variability was found in annual and seasonal streamflow changes between the two historic periods 1951-1980 and 1981-2010 considered in the study. For example, the northern watersheds show relatively small changes in streamflow discharge ranging from À6.0 to 4.2%, while the southern watersheds show relatively large increases in streamflow discharge ranging from 13.1 to 18.2%. To apportion streamflow changes to climate and nonclimatic factors, a method based on potential evapotranspiration changes is demonstrated. Results show that nonclimatic factors account for more than 60% of changes in annual runoff in Wisconsin watersheds considered in the study.

Use of long‐term (40+ year) trend data to evaluate management actions on brown trout,Salmo trutta,populations in groundwater‐fed streams

“…Improved land use practices, such as contour ploughing and use of grassed waterways to reduce soil erosion (Trimble, 2013), were predicted to increase water infiltration and subsequent discharge of cold, clear groundwater into streams. In addition, precipitation has increased throughout the Driftless Area (Dauwalter & Mitro, 2019), and collectively, these factors probably explain increased baseflow documented in several streams (Gyawali, Greb, & Block, 2015; Juckem, Hunt, Anderson, & Robertson, 2008), including one of the LTM streams (Hoxmeier & Dieterman, 2019). Increased baseflow is hypothesised to have mediated water temperatures, leading to more overall habitat volume supporting improved recruitment and higher abundance of juveniles, adults and total brown trout biomass.…”

Tendências hidrológicas na bacia hidrográfica do rio Juquiá, São Paulo

“…Variações na intensidade, frequência, duração e tipo das chuvas têm sido observadas interanualmente (TRENBERTH, 2011). Concomitantemente, alterações na cobertura do solo de bacias hidrográficas tendem a impactar as características hidrológicas das mesmas (GYAWALI et al, 2015;SOUZA-FILHO et al, 2016). Tais mudanças podem representar tendências tanto de aumento quanto de redução nos totais precipitados e, consequentemente, alterações no regime fluviométrico.…”

Impact of Land Use and Climate Change on Streamflow: An Assessment Using a Semi-Empirical Model in the Guishui Watershed of North China

“…Despite the clear motivations of most afforestation programs, the consequences of increased forest coverage are often ambiguous. For example, streamflow has been reported to both decrease and increase in various studies depending on many factors [13][14][15][16]. To make the issue more complex, this problem is strongly influenced by ongoing climate change, which alters climatic conditions and thereby changes both natural vegetation [17][18][19] and the human use of catchments worldwide [20,21].…”