Representation of Bi‐Directional Fluxes Between Groundwater and Surface Water in a Bucket‐Type Hydrological Model

Abstract

In most bucket‐type hydrological models, water can only flow from the groundwater to the stream and the flux is based on the groundwater storage. However, many catchments have losing stream sections, where streamflow recharges the groundwater. We developed a formulation to represent groundwater recharge by streamwater in a bucket‐type model and tested this formulation for the Panola Mountain Research Watershed to demonstrate its function and assess its performance. The upper reach of the Panola catchment is often dry and highly affected by flow from a bedrock outcrop; further downstream the stream is perennial. We simulated streamflow with the fully lumped version of a bucket‐type model and compared it to (a) a variant with sub‐catchments to more realistically represent the low storage and quick response from the bedrock outcrop and (b) a variant that also includes the bi‐directional exchange between the groundwater and the stream. For all three model variants, we compared simulated and observed streamflow and groundwater dynamics. Although the gain in overall model performance by including the bi‐directional exchange between the groundwater and the stream was small, the explicit representation of this exchange led to better streamflow simulations during drying‐down and wetting‐up periods. For Panola the fluxes along the stream appeared less important than subsurface drainage from the upper sub‐catchment to the downstream sub‐catchment. We recommend considering the bi‐directional fluxes between groundwater and the stream in bucket‐type hydrological models where these processes are important, and the focus of the simulations is on low flow conditions.

Catchment Properties Shape Seasonal Variation in Groundwater‐Surface Water Interaction—Geogenic Silica as a Proxy for Hydrological Turnover Induced Mixing

“…Here, the model performance enhancement was small. However, the explicit representation of bidirectional exchange led to better streamflow simulations during drying-down and wetting-up periods (Staudinger et al, 2021). Mallard et al (2014) present an empirical equation based on stream discharge magnitudes and drainage area to scale up observed HT to the catchment scale and along the stream network.…”

“…A few studies only, try to explore spatial effects of GW‐SW interaction on groundwater fluxes and indirect GW recharge on the scale of an alluvial aquifer section using hydrodynamic numerical groundwater models (e.g., Wöhling et al., 2020). The consideration of HT on the catchment scale in hydrological bucket‐type models, for example, the HBV‐model (Bergström, 1995) has been tested currently (Staudinger et al., 2021), using an additional catchment scale bidirectional exchange bucket to integrally simulate the delay effect of equilibrium driven stream bank storage within the near stream groundwater on peak flows. Here, the model performance enhancement was small.…”

Changes in water age during dry-down of a non-perennial stream

“…However, by definition, nonperennial streams become disconnected from groundwater inputs at some point in time throughout the year. Thus, stream-aquifer interactions in non-perennial streams are bidirectional in space and time (Staudinger et al, 2021), meaning that non-perennial streams can serve as focal areas of regional groundwater recharge for some period of the year, while contributing water, solutes, and materials to downstream perennial waters during the rest of the year. Indeed, non-perennial streams, especially in karst regions, are a dynamic and critical interface between the landscape, regional aquifers, and navigable waters, with far-reaching implications for water management and policy.…”

High‐resolution mapping of available water content in Senegal using iSDA Africa dataset and USDA Rosetta3 model

“…This metric represents the total amount of water that can be stored in the soil and made available to plants under normal conditions. AWC is an important parameter in bucket‐type models, used in hydrological (e.g., HBV, Seibert & Bergström, 2022; Staudinger et al, 2021) and crop modelling (e.g., DSSAT, Jones et al, 2003; AquaCrop, Salman et al, 2021; SARRA‐H/O, Baron et al, 2003; Dingkuhn et al, 2003) applications.…”