Rapid and Accurate Estimates of Streamflow Depletion Caused by Groundwater Pumping Using Analytical Depletion Functions

Abstract

Reductions in streamflow due to groundwater pumping (“streamflow depletion”) can negatively impact water users and aquatic ecosystems but are challenging to estimate due to the time and expertise required to develop numerical models often used for water management. Here we develop analytical depletion functions, which are simpler approaches consisting of (i) stream proximity criteria, which determine the stream segments impacted by a well; (ii) a depletion apportionment equation, which distributes depletion among impacted stream segments; and (iii) an analytical model to estimate streamflow depletion in each segment. We evaluate 50 analytical depletion functions via comparison to an archetypal numerical model and find that analytical depletion functions predict streamflow depletion more accurately than analytical models alone. The choice of a depletion apportionment equation has the largest impact on analytical depletion function performance and equations that consider stream network geometry perform best. The best‐performing analytical depletion function combines stream proximity criteria which expand through time to account for the increasing size of the capture zone; a web squared depletion apportionment equation, which considers stream geometry; and the Hunt analytical model, which includes streambed resistance to flow. This analytical depletion function correctly identifies the stream segment most affected by a well >70% of the time with mean absolute error < 15% of predicted depletion and performs best for wells in relatively flat settings within ~3 km of streams. Our results indicate that analytical depletion functions may be useful water management decision support tools in locations where calibrated numerical models are not available.

Streamflow depletion from groundwater pumping in contrasting hydrogeological landscapes: Evaluation and sensitivity of a new management tool

“…Groundwater pumping can negatively affect rivers, lakes, wetlands, and other surface water bodies by reducing groundwater discharge into them or, in severe cases, inducing infiltration through the streambed. Combined, these impacts are known as streamflow depletion (Barlow & Leake, 2012;Zipper et al, 2019A).…”

“…To advance the application of analytical models in real-world settings with multiple stream segments and complex stream networks, Zipper et al (2019A) developed analytical depletion functions (ADFs), which combine (1) stream proximity criteria, to determine which stream segments are most likely to be affected by a pumping well;…”

Significant baseflow reduction in the Sao Francisco River Basin

“…Persistent groundwater depletion has widely been reported in both regionally and [17][18][19][20][21][22][23][24], and quantifying groundwater depletion has been facilitated by the advent of the Terrestrial Water Storage (TWS) product measured by the Gravity Recovery and Climate Experiment (GRACE) satellite [25]. Additionally, groundwater withdrawals can decrease river flow where the stream and aquifer are hydraulically connected [26], a phenomenon known as streamflow depletion [27][28][29]. Globally, groundwater withdrawals are high and environmental streamflow limits are known to be severely exceeded in many locations [30], showing that groundwater use has increased water scarcity.…”

Cannabis and residential groundwater pumping impacts on streamflow and ecosystems in Northern California

“…To simulate monthly pumping schedules developed in section 2.1, we used the superposition approach described in Jenkins (1968). This analytical depletion function was tested against 49 other analytical depletion functions and found to produce the most accurate estimates of depletion for the Navarro River Watershed across a number of performance criteria (Zipper et al 2019a). Analytical depletion functions were implemented using the streamDepletr package (Zipper 2019) for R, and described in detail in the Supplemental Information and Zipper et al 2019a.…”

“…Here, we ask, what are the potential impacts of ongoing groundwater pumping for cannabis cultivation in the Navarro River Watershed (California, USA) on streamflow and aquatic ecosystems? We answer this question using an analytical depletion function, a newly developed tool for estimating streamflow depletion with low data and computational requirements (Zipper et al 2019a), to evaluate streamflow depletion caused by groundwater pumping for cannabis cultivation and contextualize this depletion via comparison to pumping for residential groundwater use. Specifically, we ask:…”