Spatial and Temporal Patterns in Baseflow Recession in the Continental United States

Abstract

Baseflow is often treated according to a unique storage‐discharge relationship. However, recent innovations in baseflow recession analysis have allowed novel findings regarding the variability of both the stability of baseflow and its nonlinearity (i.e., the concavity of the hydrograph), as well as the regional clustering of these characteristics. We investigate spatial and temporal patterns in the character of baseflow recession for over 1,000 watersheds in the continental United States. We discover seasonal patterns in both the stability and nonlinearity of baseflow which vary systematically across large regions. Further, we relate these baseflow characteristics to their potential physical drivers, including estimates of evapotranspiration, watershed storage, the distribution of watershed storage, and precipitation. While coincident watershed storage is the best predictor of baseflow stability in many regions (particularly the Appalachian Mountains), evapotranspiration from 2 to 3 months previous is the best predictor of baseflow stability in other regions (particularly the Pacific Northwest). We also discuss the novel finding that baseflow nonlinearity has increased significantly in most watersheds across the United States since 1980.

Drought Propagation in Contiguous U.S. Watersheds: A Process‐Based Understanding of the Role of Climate and Watershed Properties

“…Beck et al (2013) explained that under these climatic conditions, most of the watershed storage after recharge events was lost to ET due to the high atmospheric demand of water; as a result, baseflow did not vary significantly in response to the storage changes. Recently, Tashie, Pavelsky, and Emanuel (2020) also demonstrated the important role played by ET in affecting the baseflow recession characteristics in the watershed of the United States. Many other studies have also found climate properties such as aridity index, mean annual precipitation, and timing of precipitation to influence the streamflow recession behavior in watersheds (Cooper et al, 2018; Krakauer & Temimi, 2011; Peña‐Arancibia et al, 2010; van Dijk, 2010).…”

Including Regional Knowledge Improves Baseflow Signature Predictions in Large Sample Hydrology

“…Recession analysis has been used extensively to quantify the drainage behavior of catchments (Brutsaert & Nieber, 1977; Jachens et al, 2020; Tashie et al, 2020; Roques et al, 2017). It is often assumed that the relationship between the rate of change of streamflow and streamflow follows a power law.…”

“…We use the median exponent β m to describe a catchment's average recession behavior. We do not use the parameter α as it is strongly influenced by seasonal variations in catchment wetness and evapotranspiration (e.g., Dralle et al, 2015; Tashie et al, 2020).…”

Watershed‐Scale Effective Hydraulic Properties of the Continental United States

“…The effective hydraulic properties of the aquifer(s) that actually sustain baseflow have long been estimated by watershed hydrologists using hydrograph recession analysis. Here, we briefly summarize the applications of and assumptions underlying traditional hydrograph recession analysis, though we refer readers to the recession literature for a detailed accounting (Brutsaert & Nieber, 1977; Harman & Kim, 2019; Kirchner, 2009; Tallaksen, 1995; Tashie, Pavelsky, & Emanuel, 2020; Troch et al., 2013). We also outline recent reinterpretations of these methods in the following Section 1.1.2, give a more thorough description of the specific methods applied here in Section 2, and describe underlying uncertainties in Section 4.…”

“…Because the character of baseflow recession (and therefore the properties of the subsurface that are sustaining it) has been shown to vary systematically with antecedent conditions (Biswal & Nagesh Kumar, 2015; Shaw & Riha, 2012; Tashie, Pavelsky, & Emanuel, 2020), recession analysis is better seen as providing a snapshot of the effective hydraulic properties that are instantaneously sustaining baseflow (Tashie, Pavelsky, & Band, 2020). That is, recession analysis effectively integrates the hydraulic properties of only the portions of the watershed that are actively contributing to streamflow processes, which vary with time according to patterns in storage and climate.…”